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could be a cross section... but it isn´t. relax :)
just some ink :) 2 captures blended together.
enjoy :)
365 #192 - 16 -February -2008
mood: brainstorming
music: don't you know who i think i am - fall out boy
i would be a greater genius?! :-D
alternate title: "sometimes i feel like i think too much"
sometimes you just think about everything all at once, don't you ever feel like that?! this has been one of those days..
*somewhat inspired by escher's rind (and on that matter just check this one by cayusa)
*check the making of.
Barriers surrounding this art exhibit have been removed. Visitors are invited to approach and touch the exhibit, crawl underneath it but not to use it as a swing or as a tree to climb.
My hands are still sore after a sprawl while walking the dogs last night. It was a bit of a struggle to hold the camera steady. And yes Ralph, these pictures were once again taken during my so called long lunch breaks.
Neuron 2010, MCA, Circular Quay, Sydney, Australia (Monday 10 May 2010 @ 1:51pm).
Por favor, no usar esta imagen sin mi permiso explícito.
Please, don´t use this image without my explicit permission.
UN MISMO PATRÓN DE RAMIFICACIÓN.
A SAME BRANCHING PATTERN.
Comparación:
- Izquierda.- Microfotografía del Hipocampo de Rata. ( Detalle ).
El hipocampo es una estructura cerebral implicada en los procesos de Memoria.
Escalas aprox.
1 centimetro = 8 micrometros.
1 micrometro = 0,001 milímetros
- Derecha.- Fotografía de los árboles del Cantón de Ferrol ( A Coruña ).. Manipulada.
Escala aprox.
1 centímetro = 70 centímetros.
Si deseas alguna aclaración técnica puedes leer la introducción del Album.
Comparison:
- Left.-Nervous tissue. Microphotography of Rat Hippocampus. ( Detail ).
The Hippocampus is a Brain area implicated in Memory processing.
- Measurements. ( More or less ).
1 centimeter = 8 micrometer.
1 micrometer= 0,001 milimeter.
- Right.- Plants.
Photography of trees in " Cantón ". Ferrol ( A Coruña ).. Manip.
Measurements. ( More or less ).
1 centimeter = 70 centimeter.
For more technical details, please, read the Album introduction.
The dogs belonging to the piano's fairies can be found in a wide variety of colours. They are sometimes described as white with red ears may be found in all colours of the keybord.
In Kabbalah, Renaissance magic, and alchemy, the language of the birds was considered a secret and perfect language and the key to perfect knowledge, sometimes also called the langue verte, or green language (Jean Julien Fulcanelli, Heinrich Cornelius Agrippa de occulta philosophia,A black dog is a spectral or demonic entity found primarily in the folklore of the British Isles."Their discovery that certain neurons have “music selectivity” stirs questions about the role of music in human life. Why do our brains contain music-selective neurons? Could some evolutionary purpose have led to neurons devoted to music? McDermott says the study can’t answer such questions. But he is excited by the fact that it shows music has a unique biological effect. 'We presume those neurons are doing something in relation to the analysis of music that allows you to extract structure, following melodies or rhythms, or maybe extract emotion,' he says." The black dog is essentially a nocturnal apparition, some of them shapeshifters, and are often said to be associated with the Devil or described as a ghost or hellhound. Its appearance was regarded as a portent of death. It is generally supposed to be larger than a normal dog and often has large glowing eyes.[ It is sometimes associated with electrical storms (such as Black Shuck's appearance at Bungay, Suffolk) and also with crossroads, places of execution and ancient pathways. The origins of the black dog are difficult to discern. It is uncertain whether the creature originated in the Celtic or Germanic elements of British culture. Throughout European mythology, dogs have been associated with death. Examples of this are the Cŵn Annwn (Welsh),Garmr (Norse) and Cerberus (Greek), all of whom were in some way guardians of the Underworld. This association seems to be due to the scavenging habits of dogs. It is possible that the black dog is a survival of these beliefs. Black dogs are generally regarded as sinister or malevolent, and a few (such as the Barghest and Shuck) are said to be directly harmful. They may also serve as familiar spirits for witches and warlocks. Some black dogs, however, such as the Gurt Dog in Somerset and the Black Dog of the Hanging Hills in Connecticut,are said to behave benevolently. Some, known as guardian black dogs, guide travellers at night onto the right path or guard them from danger.his thought leads to another, which takes us into unexplored and perhaps unexplorable regions of Greek religious history. The chief claim made in Pithetaerus's preposterous speech to the Birds is, after all, partly true. The Birds were objects of worship to the Minoans and the early inhabitants of Greece before Zeus and his Olympian commando descended upon the peninsula. Birds were not gods; Pithetaerus does not quite say they were. Yet the bird perched on the sacred Double Axe or the pillar-tree was the Numen of the axe or the tree. Technically, the Language of the Birds - as it was often described in folk tales and myths in general - literally referred to what anyone might assume it did: the way birds communicate. And, to be able to understand this language endowed one with special powers, knowledge and abilities. As time went on, however, the phrase took on more occult implications. in medieval France it became the secret "Green Language" of the Freemasons and Knights Templar - la langue des oiseaux - and was possibly also utilized by the Troubadours (or Trouvères). During the Renaissance, there were apparently a number of musical languages inspired by birdsong, although at least a few of these were probably composed of simple signals in ways similar to those used by the indigenous peoples of the Americas and elsewhere.When I first began using the phrase "the Language of the Birds" to describe my own understanding of mysticism, I had almost no formal knowledge of the phrase's history; I had initially found it in reference to a Sufi text, and was attracted to it in a poetic sense. After all, the phrase has a nice resonance to it. Eventually, however, I began to equate it with language of the higher consciousness, specifically that of the creative muse and its role in automatism. At the same time, you began to intuit there was a transdimensional aspect to it, which you referred to as "the memory of sound". That is, while there is the physicality of sound and its effect on our senses, there are also immaterial, subliminal codes embedded in sound which effect us both emotionally and spiritually in ways that are not currently understood. In this sense, music is, in fact, magic.The Minoans believed, as Nilson says, that the gods - or, to put it more exactly, the divine power - appeared in the form of birds. Again, the most important and wide-spread method of communication with the divine power was by augury. The birds knew the weather; they knew when good luck or bad was to be expected; they gave clear warning of the future to those who could read their messages. Could they have known what was coming so well unless indeed it was partly they who made it come? "Sometimes mythological birds create more than the physical world. Cultures in northern Europe and Asia credited birds with establishing their social orders, especially kingships. A golden-winged eagle was said to have put the first Mongol emperor on his throne. The Japanese believed that sacred birds guided their second emperor in conquering his enemies before the founding of his dynasty. The Magyar people claimed that a giant eagle, falcon, or hawk had led their first king into Hungary, where he founded their nation. The Magyars looked upon this bird as their mythical ancestor...Many myths have linked birds to the arrival of life or death. With their power of flight, these winged creatures were seen as carriers or symbols of the human soul, or as the soul itself, flying heavenward after a person died. A bird may represent both the soul of the dead and a deity at the same time. Some cultures have associated birds with birth, claiming that a person’s soul arrived on earth in bird form."Lastly, we come to the Music Box, the third element of this introduction. Portions of it first made its appearance on this blog in February around Valentine's Day, and was meant to be the metaphorical fulcrum about which my "Ode to Love" was spun. That particular post died in the water, however - for numerous reasons - and, although the initial post is still online - and might be referred to in the future - you may as well consider this one its replacement.
In "Still Life with Music Box" the floating panels of the box I created last month have finally come together into an actual (although virtual) object. In order to visualize the box, I inadvertently made a model of it with cardboard and inkjet prints and then snapped its photograph. A great deal more work was involved, but amongst the objects, only three were entirely contrived... and I'm guessing it's pretty obvious which ones. I'm no master, but I did the best I could (without driving myself insane). (Hint: The wooden table supporting the objects is real enough - it was created by my grandfather at some point around the turn of the last century.)
As it so happens, as lyrical as the music box appears, it's creation was the result of a geometrical inquiry... an inquiry that's particularly relevant in any discussion of love and alchemy when you come right down to it, but I'll save the geometry for the next post and reflect on the music box's general importance here; that is, in its role as a generator of music, and, at the same time, a collector of love tokens, that is, a keepsake box.
Initially, I referred to the music box as the "Love Box"... totally overlooking the fact that the actual term is American slang for a certain portion of a woman's anatomy. That being said, that "love box" has the particularly feminine connotations it does, is not really inappropriate here. Woman, after all, do have a peculiar predilection for keeping memorable items in special boxes, especially as young girls. Our little magic boxes... full of talismanic detritus we've collected over the years... a coin, jewelry, a shred of hair, a crumbling flower head, a photo, a signature, stones, bones... whatever. Generally the tokens are kept to remind us of lovers or loved ones... small trophies for experiences that may eventually retreat into a mental shadowland in the same way the objects themselves have retreated into the shadowy recesses of the box. But, no matter. The box becomes a sort of artificial memory bank... a collection of three-dimensional objects representing transdimensional events in the same way a collection of symbols do.
In the end, whether we're talking about musical codes, alchemical codes, or the enigmatic chemistry of love and attraction, some type of hidden language is involved... as is some kind of communication that lies outside the bounds of what is consciously understood. When we find ourselves in tears while listening to an old, wistful tune, or find ourselves suddenly uplifted by the memory of a lover's smile, although utterly immaterial, the experience is real, and has as much power to move us, inspire us, and inform us as any collection of words (up to and including the ones you are presently reading)! And that, is the Language of the Birds.
As it stands, for all our technological prowess, we, as a species, have not inwardly changed very much from the days our savage ancestors danced naked around a fire; the difference being, our savage ancestors very likely understood a few things we modern specimens of humanity have forgotten. And, one of those "things" is the origin of music. My guess is that if prehistoric humans could somehow convey to us certain facets of our prehistory, they might inform us that humans did not, after all, invent music. The were taught.
Well, do the math. Songbirds are thought to have evolved 50 million years ago in an area which is now Australia. Modern humans, on the other hand, are generally considered to have arisen out of Africa a paltry 250,000 years old. In other words, birds were singing millions of years before humans even discovered the coveted fire they'd eventually dance around."Their discovery that certain neurons have “music selectivity” stirs questions about the role of music in human life. Why do our brains contain music-selective neurons? Could some evolutionary purpose have led to neurons devoted to music? McDermott says the study can’t answer such questions. But he is excited by the fact that it shows music has a unique biological effect. 'We presume those neurons are doing something in relation to the analysis of music that allows you to extract structure, following melodies or rhythms, or maybe extract emotion,' he says."
"As Spring reaches its midpoint, night and day stand in perfect balance, with light on the increase. The young Sun God now celebrates a hierogamy (sacred marriage) with the young Maiden Goddess, who conceives. In nine months, she will again become the Great Mother. It is a time of great fertility, new growth, and newborn animals."
- From a short entry for the Wiccan holiday, Ostara (March 20th), found on this page.
"Hieros gamos or Hierogamy (Greek ἱερὸς γάμος, ἱερογαμία "holy marriage") refers to a sexual ritual that plays out a marriage between a god and a goddess, especially when enacted in a symbolic ritual where human participants represent the deities.
The notion of hieros gamos does not presuppose actual performance in ritual, but is also used in purely symbolic or mythological context, notably in alchemy and hence in Jungian psychology.
In Wicca, the Great Rite is a ritual based on the Hieros Gamos. It is generally enacted symbolically by a dagger being placed point first into a chalice, the action symbolizing the union of the male and female divine in the Hieros gamos. In British Traditional Wicca, the Great Rite is sometimes carried out in actuality by the High Priest and High Priestess."
- From the Wiki entry for Hieros gamos.
"One of the most fascinating explorations of the psychological analogues of alchemy was given to us by Jung in a lengthy essay not usually classified as one of his alchemical writings, entitled The Psychology of the Transference. In this study Jung employed the ten pictures illustrating the opus of alchemical transormation contained in a classic called Rosarium Philosophorum (Rosary of the Philosophers), where the dual powers of the "King" and "Queen" are shown to undergo a number of phases of their own mystico-erotic relationship and eventually unite in a new, androgynous being, called in the text "the noble Empress". The term "transference is used by Jung as a psychological synonym for love, which in interpersonal relations as well as in depth-psychological analysis serves the role of the great healer of the sorrows and injuries of living."
- From "Alchemical Eros" via C. G. Jung and the Alchemical Renewal by Stephen A. Hoeller, (an article from the Gnosis magazine archive).
"In this hermetic side of alchemy, the "philosopher's stone", supposed to to be the most tangible and dense crystalization or condensation of a subtle substance, became a metaphor for an inner potential of the spirit and reason to evolve from a lower state of imperfection and vice (symbolized by the base metals) to a higher state of enlightenment and perfection (symbolized by gold). In this view, spiritual elevation, the transmutation of metals, and the purification and rejuvenation of the body were seen to be manifestations of the same concept."
- From the Crystalinks entry for Philospher's Stone.
***
But, what do we really mean by phrases like "the realm of the psyche" or "spiritual elevation"? Obviously, this question (in various forms) has been at the heart of the world's philosophy the millisecond humanity became disconnected from its initial source. At some point, we simply forgot. No longer having any real understanding of our essential natures we - specifically those of us in the west - allowed the various spin-doctors to take over. "And all the king's horses and all the king's men, couldn't put Humpty (the egg) together again... "
Except for one thing. In spite of the failure on the part of "the king and his men", there is one force that could - and one force that always will - "put" us together again, and that is the force of Love. While the physical aspect of Love exists and is very important to us in a biological and psychological sense, Love also reminds us that we are, in essence, immaterial entities. We know that we are truly alive because we love. We are assured our lives have meaning because we love. We conceive of things like "eternity" and "forever" because we love.... and we know Love, like Life itself, cannot simply dissipate because, although it influences the material realm, it is not really of it. Love knows no atrophy.
Alchemy itself, as a psuedo-science and precursor to chemistry, was primarily founded upon the concept that there was some substance - the Philopher's Stone - that when procured a certain way via certain rituals could transform base materials literally into gold. This, in any case, is the general fable. But when one takes a peek at all the literature, and all the various graphic material pertaining to alchemy and the alchemists, one thing immediately becomes clear: alchemy was no mere chemistry experiment.
But, just what was alchemy exactly? What was really meant by "the Great Work"? In reality, there is no exact definition of alchemy. It seems to have slowly evolved both in the East and in the West, and, at all times, to have been both an exoteric as well as an esoteric inquiry. On one hand, the quest was to cure disease, attain immortality and transmute base substances... on the other the goal was divine and spiritual knowledge and the perfection of the soul. The Great Work was generally in reference to creating or attaining the Philosopher's Stone, but once again, the "stone" had both material and mystical properties. One might say the stone itself was merely metaphorical for a sublime state of being or for the secret of creation itself.
One might go further and intuit the true Philosopher's Stone was the force of Love, but this side of alchemy has been mostly ignored except in Hermetic philosophy, in which the heiros gamos (see quotes above), or the "mysterium conjunctionis" is a crucial part of the philosophy. It was not lost on Carl Jung, however, who wrote in Volume 14 (translatable text) of his Collected Works:
“In light of eternity, it is a wedding, a mysterium conjunctionis. The soul attains, as it were its missing half, it achieves wholeness.”
LOOK KG 243 racer from late 1990's built with Columbus Neuron steel. Components are generally 2000's - but a mix of new and old.
Photo: Thomas Ohlsson Photography
www.thomasohlsson.com | 500px | Facebook | Flickr | Instagram
Left: This is your brain. Right: This is your brain after intermittent binge drinking.
DURHAM, N.C. -- Studies have demonstrated how just a few sessions of binge drinking during adolescence can knock out neurons (shown in blue arch) in the hippocampus, the brain’s memory core.
But researchers at Duke Medicine have found that binge drinking can also send hippocampal cells called astrocytes (shown in green) awry later in adulthood, potentially impairing the brain’s ability to form new synapses and heal itself from injury.
The study, published November 5 in Alcoholism: Clinical & Experimental Research, used a rodent model as a surrogate for the adolescent human brain. The researchers exposed the animals to alcohol doses that would result in a blood-alcohol concentration of about .15 in humans.
Researchers didn’t see immediate effects on astrocytes, but once the animals reached adulthood, the cells appeared to go into overdrive.
Image credit: Mary-Louise Risher/Duke Medicine
This image is not owned by the NIH. It is shared with the public under license. If you have a question about using or reproducing this image, please contact the creator listed in the credits. All rights to the work remain with the original creator.
NIH funding from:
The National Institute on Alcohol Abuse and Alcoholism (NIAAA),
The National Institute on Drug Abuse (NIDA)
Cracking day today, sun was out and not a drop of rain, so went for walk with the girlfriend up the local woods, took the camera along too,Haven't done one of these shots before so thought i would try one as we were out.
shot of the trees then when i got home,went crazy with the hue slider,liking the green ;)
Created by Natasha Molotkova of PaperGraphic.
Blogged: www.allthingspaper.net/2013/07/new-quilled-work-from-pape...
LOOK KG 243 racer from late 1990's built with Columbus Neuron steel. Components are generally 2000's - but a mix of new and old.
Photo: Thomas Ohlsson Photography
www.thomasohlsson.com | 500px | Facebook | Flickr | Instagram
Por favor, no usar esta imagen sin mi permiso explícito.
Please, don´t use this image without my explicit permission.
Mejor sobre negro. Haz click en la foto.
Better on black.Just click on the pic.
Corteza Cerebral de Erizo de tierra.
En esta estación del año, de árboles con ramas desnudas, yo os muestro estas otras ramas, las neuronales del " Bosque Cerebral ".
Proceden de mis trabajos de investigación en el cerebro de diferentes mamíferos. Son fotografías obtenidas con microscopio sobre material teñido de forma que las neuronas se visualizan en color pardo-negro sobre fondo amarillento.
Así visto, el Bosque Cerebral me parece un elemento muy sugestivo.
Mi pretensión en esta foto y en todas las del album, es únicamente ESTÉTICA, no científica, y así os pido que lo mireis.
Si deseais alguna aclaración técnica podeis leer la introducción del Album.
Hedgehog Cerebral Cortex.
In this season of naked branches in the trees, i show you these neuronal branchings on Cerebral Trees. They come from my research works about differents mammals´ brains. These are micro-photographies on stained matherial, so the neurons appear in dark brown-black on yellow background.
I think this Brain Forest is a very attractive and aesthetic element. So, my aim in this picture and in the album is JUST AESTHETIC, no scientific, and like that you should look at it.
For more technical details, please, read the album introduction.
Un buen amigo alguna vez sabiamente dijo: hormona mata neurona.
---
A good friend once wisely said: hormone beats neuron.
Por favor, no usar esta imagen sin mi permiso explícito.
Please, don´t use this picture without my explicit permission.
Proceso:
Arriba.- Izda. Microfotografía de Cerebro
( Sistema Límbico ) de
rata, mostrando una N.
Bipolar ( Dcha.) y un
elemento glial. ( Izda.).
Dcha. Escaneado en grises.
Abajo.- " Neurona Bipolar ama...".
Dibujo a mano.
Process:
Above.- Left.-Microphotography of rat
Brain ( Limbic System ),
showing a Bipolar Neur.
( Right ) and a Glial
element. ( Left )
Right.- Scanned in grey.
Below.- " Bipolar Neuron loves...".
Hand-Drawn.
Neuron is a European collaboration project to develop a UCAV demonstrator, Unmanned Combat Aerial Vehicle. Six aviation industries are participating. The work packages being managed by Saab relate to low signature (stealth) technology, flight testing, aerodynamics, avionics, fuel system, the critical part of the ground station, as well as the design and production of the main fuselage. The crafts’ length is 10 metres, width 12 metres and weight 7 tonnes. The first flight is planned for 2012.
Nation of China systematically organizes itself to operate just like a brain, with each individual acting as a neuron (forming what has come to be called a "Blockhead")Chinese thought, including seemingly disparate fields such as geomancy or Feng shui, astrology, traditional Chinese medicin, as seen on "Floating Perspective," a technique which displaces the static eye of the viewer and highlights the differences between Chinese and Western modes of spatial representation. It summarizes these into three ways of minor, middle and great achievement, and illustrates each with charts, explanations and formulae..The 5-volumed Record of the Realization of Perfection by the Concourse of Immortals of West Mountain ( 《西山群仙會真記》 Xishan Qunxian Huizhen Ji ) was authored by Shi Jianwu and compiled by Li Song. Shi, whose title was "The Perfect Man of Huayang" ( 華陽真人 Huayang Zhenren ) lived during the Tang Dynasty. After his success in the national civil service examinations, Shi remained secluded as a Daoist on the West Mountain (present Jiangxi province) to cultivate the Dao. But some say that there were two men named "Shi Jianwu". the Comprehensive Annotated Bibliography of the Four Repositories ( 《四庫提要》 Siku Tiyao ) say some Daoists, under the name of Shi, wrote this book during the Jin and Yuan Dynasties. Still some hold that the book should have been completed no later than the Northern Song. The preface by the author states, the book, in secret accordance with earlier and later sages, imitating the number of five agents ( 五行 Wuxing ) and corresponding to the pure Yang one-breath ( 純陽一氣 Chunyang Yiqi ), expounds the mystery and supreme truth of the Zhong-Lu lineage in one five-volume book. The contents, similar to the Transmission of Dao by Zhongli Chuan and Lü Dongbin ( 《鍾呂傳道集》 Zhinglu Chuandao Ji ), explains the ways of inner alchemy, citing the Supreme Hidden Book ( 《太上隱書》 Taishang Yinshu ), Record of the Western Mountain ( 《西山記》 Xishan Ji ), Numinous Treasure Book of Inner Contemplation ( 《靈寶內觀經》 Lingbao Neiguan Jing ), the Book of Communion with the Mystery ( 《通玄經》 Tongxuan Jing ) and quotations of the immortals Ge, Yin and Lu. The theme, based on Three Ways Unified and Normalized ( 《參同契》 Cantong Qi ), expounds the theory about increasing and reducing fire ( 抽添 Choutian ) and the practice that leads to liberation.
en.daoinfo.org/wiki/Record_of_the_Realization_of_Perfecti...
Neuron 2010 by Roxy Paine, a 44-year old New York artist, is for exhibition in
The 17th Biennale of Sydney (12 May - 1 Aug 2010). The exhibition, directed by David Elliott, and titled The Beauty of Distance: Songs of Survival in a Precarious Age will showcase new and recent works by Sydney and international artists at Sydney's leading cultural institutions, contemporary art spaces and heritage sites.
Roxy Paine had made a series of large structures based on the forms of trees with their roots exposed that have been handmade out of industrial stainless steel pipe. These works are generically called Dendroids. Neuron 2010 continues this idea, focusing even more on dandrites and synapses, the means by which information, knowledge and experience are electronically transmitted through a body........[excerpts from information board]
Neuron 2010, MCA, Circular Quay, Sydney, Australia (Tuesday 4 May 2010 @ 8:51am).
Nearly everyone has had headache pain, and most of us have had it many times. A minor headache is little more than a nuisance that's relieved by an over-the-counter pain reliever, some food or coffee, or a short rest. But if your headache is severe or unusual, you might worry about stroke, a tumor, or a blood clot. Fortunately, such problems are rare. Still, you should know when a headache needs urgent care and how to control the vast majority of headaches that are not threatening to your health. Headache is defined as a pain arising from the head or upper neck of the body. The pain originates from the tissues and structures that surround the skull or the brain because the brain itself has no nerves that give rise to the sensation of pain (pain fibers). The thin layer of tissue (periosteum) that surrounds bones, muscles that encase the skull, sinuses, eyes, and ears, as well as thin tissues that cover the surface of the brain and spinal cord (meninges), arteries, veins, and nerves, all can become inflamed or irritated and cause headache. The pain may be a dull ache, sharp, throbbing, constant, intermittent, mild, or intense. Headaches can be more complicated than most people realize. Different kinds can have their own set of symptoms, happen for unique reasons, and need different kinds of treatment. Once you know the type of headache you have, you and your doctor can find the treatment that’s most likely to help and even try to prevent them.
Headache is the symptom of pain anywhere in the region of the head or neck. It occurs in migraines (sharp, or throbbing pains), tension-type headaches, and cluster headaches.Frequent headaches can affect relationships and employment. There is also an increased risk of depression in those with severe headaches. Headaches can occur as a result of many conditions whether serious or not. There are a number of different classification systems for headaches. The most well-recognized is that of the International Headache Society. Causes of headaches may include fatigue, sleep deprivation, stress, the effects of medications, the effects of recreational drugs, viral infections, loud noises, common colds, head injury, rapid ingestion of a very cold food or beverage, and dental or sinus issues.The pain you feel during a headache comes from a mix of signals between your brain, blood vessels, and nearby nerves. Specific nerves of the blood vessels and head muscles switch on and send pain signals to your brain. But it's not clear why these signals turn on in the first place. People often get headaches because of:
Illness: such as an infection, cold, or fever. They’re also common with conditions like sinusitis (inflammation of the sinuses), a throat infection, or an ear infection. In some cases, the headaches may be the result of a blow to the head or rarely, a sign of a more serious medical problem. Stress: Emotional stress and depression as well as alcohol use, skipping meals, changes in sleep patterns, and taking too much medication. Other causes include eyestrain and neck or back strain due to poor posture. Your environment, including secondhand tobacco smoke, strong smells from household chemicals or perfumes, allergens, and certain foods. Stress, pollution, noise, lighting, and weather changes are other possible triggers. Headaches, especially migraine headaches, tend to run in families. Most children and teens (90%) who have migraines have other family members who get them. When both parents have a history of migraines, there is a 70% chance that their child will also have them. If only one parent has a history of these headaches, the risk drops to 25%-50%.
Doctors don’t know exactly what causes migraines. A popular theory is that triggers cause unusual brain activity, which causes changes in the blood vessels there. Some forms of migraines are linked to genetic problems in certain parts of the brain. Too much physical activity can also trigger a migraine in adults. Treatment of a headache depends on the underlying cause, but commonly involves pain medication. Some form of headache is one of the most commonly experienced of all physical discomforts. About half of adults have a headache in a given year. Tension headaches are the most common, affecting about 1.6 billion people (21.8% of the population) followed by migraine headaches which affect about 848 million (11.7%)
There are more than two hundred types of headaches. Some are harmless and some are life-threatening. The description of the headache and findings on neurological examination, determine whether additional tests are needed and what treatment is best. Once you get your headaches diagnosed correctly, you can start the right treatment plan for your symptoms. The first step is to talk to your doctor about your headaches. She’ll give you a physical exam and ask you about the symptoms you have and how often they happen. It’s important to be as complete as possible with these descriptions. Give your doctor a list of things that cause your headaches, make them worse, and what helps you feel better. You can track details in a headache diary to help your doctor diagnose your problem. Most people don’t need special diagnostic tests. But sometimes, doctors suggest a CT scan or MRI to look for problems inside your brain that might cause your headaches. Skull X-rays are not helpful. An EEG (electroencephalogram) is also unnecessary unless you have passed out when you had a headache. If your headache symptoms get worse or happen more often despite treatment, ask your doctor to refer you to a headache specialist. If you need more information, contact one of the organizations in the resource list for a list of member doctors in your state.
Your doctor may recommend different types of treatment to try. She also might recommend more testing or refer you to a headache specialist. The treatment you need will depend on a lot of things, including the type of headache you get, how often, and its cause. Some people don’t need medical help at all. But those who do might get medications, counseling, stress management, and biofeedback. Your doctor will make a treatment plan to meet your specific needs. Once you start a treatment program, keep track of how well it’s working. A headache diary can help you note any patterns or changes in how you feel. Know that it may take some time for you and your doctor to find the best treatment plan, so try to be patient. Be honest with her about what is and isn’t working for you. Even though you’re getting treatment, you should still steer clear of the things you know can trigger your problem, like foods or smells. And it’s important to stick to healthy habits that will keep you feeling good, like regular exercise, enough sleep, and a healthy diet. Also, make your scheduled follow-up appointments so your doctor can see how you’re doing and make changes in the treatment program if you need them.
Headaches are broadly classified as "primary" or "secondary". Primary headaches are benign, recurrent headaches not caused by underlying disease or structural problems. For example, migraine is a type of primary headache. While primary headaches may cause significant daily pain and disability, they are not dangerous. Secondary headaches are caused by an underlying disease, like an infection, head injury, vascular disorders, brain bleed or tumors. Secondary headaches can be harmless or dangerous. Certain "red flags" or warning signs indicate a secondary headache may be dangerous.Occurring in about three of every four adults, tension headaches are the most common of all headaches. In most cases, they are mild to moderate in severity and occur infrequently. But a few people get severe tension headaches, and some are troubled by them for three or four times a week. The typical tension headache produces a dull, squeezing pain on both sides of the head. People with strong tension headaches may feel like their head is in a vise. The shoulders and neck can also ache. Some tension headaches are triggered by fatigue, emotional stress, or problems involving the muscles or joints of the neck or jaw. Most last for 20 minutes to two hours.If you get occasional tension-type headaches, you can take care of them yourself. Over-the-counter pain relievers such as acetaminophen (Tylenol, other brands) and nonsteroidal anti-inflammatories (NSAIDs) such as aspirin, naproxen (Aleve, other brands), or ibuprofen (Motrin, Advil, other brands) often do the trick, but follow the directions on the label, and never take more than you should. A heating pad or warm shower may help; some people feel better with a short nap or light snack. If you get frequent tension-type headaches, try to identify triggers so you can avoid them. Don't get overtired or skip meals. Learn relaxation techniques; yoga is particularly helpful because it can relax both your mind and your neck muscles. If you clench your jaw or grind your teeth at night, a bite plate may help. If you need more help, your doctor may prescribe a stronger pain medication or a muscle relaxant to control headache pain. Many people with recurrent tension-type headaches can prevent attacks by taking a tricyclic antidepressant such as amitriptyline (Elavil, generic). Fortunately, most people with tension-type headaches will do very well with simpler programs. 90% of all headaches are primary headaches. Primary headaches usually first start when people are between 20 and 40 years old. The most common types of primary headaches are migraines and tension-type headaches.[6] They have different characteristics. Migraines typically present with pulsing head pain, nausea, photophobia (sensitivity to light) and phonophobia (sensitivity to sound). Tension-type headaches usually present with non-pulsing "bandlike" pressure on both sides of the head, not accompanied by other symptoms. Other very rare types of primary headaches include: cluster headaches: This type is intense and feels like a burning or piercing pain behind or around one eye, either throbbing or constant. It’s the least common but the most severe type of headache. The pain can be so bad that most people with cluster headaches can’t sit still and will often pace during an attack. On the side of the pain, the eyelid droops, the eye reddens, pupil gets smaller or the eye tears. The nostril on that side runs or stuffs
They’re called “cluster headaches” because they tend to happen in groups. You might get them one to three times per day during a cluster period, which may last 2 weeks to 3 months. Each headache attack last 15 mins to 3 hours and often wakens the patient from sleep. The headaches may disappear completely (go into "remission") for months or years, only to come back again. Cluster headaches affect men 3-4 times more often than women.short episodes (15–180 minutes) of severe pain, usually around one eye, with autonomic symptoms (tearing, red eye, nasal congestion) which occur at the same time every day. Cluster headaches can be treated with triptans and prevented with prednisone, ergotamine or lithium. trigeminal neuralgia or occipital neuralgia: shooting face pain hemicrania continua: continuous unilateral pain with episodes of severe pain. Hemicrania continua can be relieved by the medication indomethacin.
primary stabbing headache: recurrent episodes of stabbing "ice pick pain" or "jabs and jolts" for 1 second to several minutes without autonomic symptoms (tearing, red eye, nasal congestion). These headaches can be treated with indomethacin. primary cough headache: starts suddenly and lasts for several minutes after coughing, sneezing or straining (anything that may increase pressure in the head). Serious causes (see secondary headaches red flag section) must be ruled out before a diagnosis of "benign" primary cough headache can be made. primary exertional headache: throbbing, pulsatile pain which starts during or after exercising, lasting for 5 minutes to 24 hours. The mechanism behind these headaches is unclear, possibly due to straining causing veins in the head to dilate, causing pain. These headaches can be prevented by not exercising too strenuously and can be treated with medications such as indomethacin. primary sex headache: dull, bilateral headache that starts during sexual activity and becomes much worse during orgasm. These headaches are thought to be due to lower pressure in the head during sex. It is important to realize that headaches that begin during orgasm may be due to a subarachnoid hemorrhage, so serious causes must be ruled out first. These headaches are treated by advising the person to stop sex if they develop a headache. Medications such as propranolol and diltiazem can also be helpful.
hypnic headache: moderate-severe headache that starts a few hours after falling asleep and lasts 15–30 minutes. The headache may recur several times during night. Hypnic headaches are usually in older women. They may be treated with lithium.
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Headaches may be caused by problems elsewhere in the head or neck. Some of these are not harmful, such as cervicogenic headache (pain arising from the neck muscles). Medication overuse headache may occur in those using excessive painkillers for headaches, paradoxically causing worsening headaches.More serious causes of secondary headaches include: meningitis: inflammation of the meninges which presents with fever and meningismus, or stiff neck
bleeding inside the brain (intracranial hemorrhage)
subarachnoid hemorrhage (acute, severe headache, stiff neck WITHOUT fever) ruptured aneurysm, arteriovenous malformation, intraparenchymal hemorrhage (headache only)
brain tumor: dull headache, worse with exertion and change in position, accompanied by nausea and vomiting. Often, the person will have nausea and vomiting for weeks before the headache starts. temporal arteritis: inflammatory disease of arteries common in the elderly (average age 70) with fever, headache, weight loss, jaw claudication, tender vessels by the temples, polymyalgia rheumatica acute closed angle glaucoma (increased pressure in the eyeball): headache that starts with eye pain, blurry vision, associated with nausea and vomiting. On physical exam, the person will have a red eye and a fixed, mid dilated pupil. Post-ictal headaches: Headaches that happen after a convulsion or other type of seizure, as part of the period after the seizure (the post-ictal state) Gastrointestinal disorders may cause headaches, including Helicobacter pylori infection, celiac disease, non-celiac gluten sensitivity, irritable bowel syndrome, inflammatory bowel disease, gastroparesis, and hepatobiliary disorders. The treatment of the gastrointestinal disorders may lead to a remission or improvement of headaches.
The brain itself is not sensitive to pain, because it lacks pain receptors. However, several areas of the head and neck do have pain receptors and can thus sense pain. These include the extracranial arteries, middle meningeal artery, large veins, venous sinuses, cranial and spinal nerves, head and neck muscles, the meninges, falx cerebri, parts of the brainstem, eyes, ears, teeth and lining of the mouth.Pial arteries, rather than pial veins are responsible for pain production. Headaches often result from traction to or irritation of the meninges and blood vessels. The nociceptors may be stimulated by head trauma or tumors and cause headaches. Blood vessel spasms, dilated blood vessels, inflammation or infection of meninges and muscular tension can also stimulate nociceptors and cause pain. Once stimulated, a nociceptor sends a message up the length of the nerve fiber to the nerve cells in the brain, signaling that a part of the body hurts.
Primary headaches are more difficult to understand than secondary headaches. The exact mechanisms which cause migraines, tension headaches and cluster headaches are not known. There have been different theories over time which attempt to explain what happens in the brain to cause these headaches.
Migraines are currently thought to be caused by dysfunction of the nerves in the brain. This condition is accompanied by intense headaches. These headaches are often described as pounding, throbbing pain. They can last from 4 hours to 3 days and usually happen one to four times per month. Along with the pain, people have other symptoms, such as sensitivity to light, noise, or smells; nausea or vomiting; loss of appetite; and upset stomach or belly pain. When a child has a migraine, she may look pale, feel dizzy, and have blurry vision, fever, and an upset stomach.Migraines occur less often than tension-type headaches, but they are usually much more severe. They are two to three times more common in women than men, but that's small consolation if you are among the 6% to 8% of all men who have migraines. And since a Harvard study of 20,084 men age 40 to 84 reported that having migraines boosts the risk of heart attacks by 42%, men with migraines should take their headaches to heart. Neurologists believe that migraines are caused by changes in the brain's blood flow and nerve cell activity. Genetics play a role since 70% of migraine victims have at least one close relative with the problem. Migraine triggers. Although a migraine can come on without warning, it is often set off by a trigger. The things that set off a migraine vary from person to person, but a migraine sufferer usually remains sensitive to the same triggers. A small percentage of children's migraines include digestive symptoms, like vomiting, that happen about once a month. Previously, migraines were thought to be caused by a primary problem with the blood vessels in the brain.This vascular theory, which was developed in the 20th century by Wolff, suggested that the aura in migraines is caused by constriction of intracranial vessels (vessels inside the brain), and the headache itself is caused by rebound dilation of extracranial vessels (vessels just outside the brain). Dilation of these extracranial blood vessels activates the pain receptors in the surrounding nerves, causing a headache. The vascular theory is no longer accepted. Studies have shown migraine head pain is not accompanied by extracranial vasodilation, but rather only has some mild intracranial vasodilation.
Currently, most specialists think migraines are due to a primary problem with the nerves in the brain. Auras are thought to be caused by a wave of increased activity of neurons in the cerebral cortex (a part of the brain) known as cortical spreading depression followed by a period of depressed activity. Some people think headaches are caused by the activation of sensory nerves which release peptides or serotonin, causing inflammation in arteries, dura and meninges and also cause some vasodilation. Triptans, medications which treat migraines, block serotonin receptors and constrict blood vessels. People who are more susceptible to experience migraines without headache are those who have a family history of migraines, women, and women who are experiencing hormonal changes or are taking birth control pills or are prescribed hormone replacement therapy. Tension headaches are thought to be caused by activation of peripheral nerves in the head and neck muscles Cluster headaches involve overactivation of the trigeminal nerve and hypothalamus in the brain, but the exact cause is unknown.
Edit: Hurray for the GFP Nobel Prize. Aside from just green, it is a wonderful rainbow of tools providing results...
20X magnification of the somatosensory cortex of a mouse brain slice. These little guys have green flourescent protein (GFP) from a jelly-fish expressed in a subset of their neurons. Layer V neuron cell bodies are the teardrop shaped things at the bottom and then the dendrite reaches up like a tree to then bifurcate near the top (pial surface).
That the sperm of a man be putrefied by itself in a sealed cucurbit for forty days with the highest degree of putrefaction in a horse’s womb, or at least so long that it comes to life and moves itself, and stirs, which is easily observed. After this time, it will look somewhat like a man, but transparent, without a body. If, after this, it be fed wisely with the Arcanum of human blood, and be nourished for up to forty weeks, and be kept in the even heat of the horse’s womb, a living human child grows therefrom, with all its members like another child, which is born of a woman, but much smaller.Comparisons have been made with several similar concepts in the writings of earlier alchemists. Although the actual word "homunculus" was never used, Carl Jung believed that the concept first appeared in the Visions of Zosimos, written in the third century AD. In the visions, Zosimos encounters a priest who changes into "the opposite of himself, into a mutilated anthroparion".The Greek word "anthroparion" is similar to "homunculus" – a diminutive form of "man". Zosimos subsequently encounters other anthroparion in his dream but there is no mention of the creation of artificial life. In his commentary, Jung equates the homunculus with the Philosopher’s Stone, and the "inner man" in parallel with ChristIn Islamic alchemy, Takwin (Arabic: تكوين) was a goal of certain Muslim alchemists, a notable one being Jābir ibn Hayyān. In the alchemical context, Takwin refers to the artificial creation of life in the laboratory, up to and including human lifeThe homunculus continued to appear in alchemical writings after Paracelsus' time. The Chymical Wedding of Christian Rosenkreutz (1616) for example, concludes with the creation of a male and female form identified as Homunculi duo. The allegorical text suggests to the reader that the ultimate goal of alchemy is not chrysopoeia, but it is instead the artificial generation of man. Here, the creation of homunculi symbolically represents spiritual regeneration and Christian soteriology In 1775, Count Johann Ferdinand von Kufstein, together with Abbé Geloni, an Italian cleric, are reputed to have created ten homunculi with the ability to foresee the future, which von Kufstein kept in glass containers at his Masonic lodge in Vienna. Dr. Emil Besetzny's Masonic handbook, Die Sphinx, devoted an entire chapter to the wahrsagenden Geister (scrying ghosts). These are reputed to have been seen by several people, including local dignitaries The homunculus is commonly used today in scientific disciplines such as psychology as a teaching or memory tool to describe the distorted scale model of a human drawn or sculpted to reflect the relative space human body parts occupy on the somatosensory cortex (the "sensory homunculus") and the motor cortex (the "motor homunculus"). Both the motor and sensory homonculi usually appear as small men superimposed over the top of precentral or postcentral gyri for motor and sensory cortices respectively. The homunculus is oriented with feet medial and shoulders lateral on top of both the precentral and the postcentral gyrus (for both motor and sensory). The man's head is depicted upside down in relation to the rest of the body such that the forehead is closest to the shoulders. The lips, hands, feet and sex organs have more sensory neurons than other parts of the body, so the homunculus has correspondingly large lips, hands, feet, and genitals. The motor homunculus is very similar to the sensory homunculus, but differs in several ways. Specifically, the motor homunculus has a portion for the tongue most lateral while the sensory homunculus has an area for genitalia most medial and an area for visceral organs most lateral.[11][12] Well known in the field of neurology, this is also commonly called "the little man inside the brain." This scientific model is known as the cortical homunculus.In medical science, the term homunculus is sometimes applied to certain fetus-like ovarian cystic teratomae. These will sometimes contain hair, sebaceous material and in some cases cartilagous or bony structures
Homunculi can be found in centuries worth of literature. These fictions are primarily centred around imaginative speculations on the quest for artificial life associated with Paracelsian alchemy. One of the very earliest literary references occurs in Thomas Browne's Religio Medici (1643), in which the author states:I am not of Paracelsus minde that boldly delivers a receipt to make a man without conjunction,.The fable of the alchemically-created homunculus may have been central in Mary Shelley's novel Frankenstein (1818). Professor Radu Florescu suggests that Johann Conrad Dippel, an alchemist born in Castle Frankenstein, might have been the inspiration for the fictional Victor Frankenstein. German playwright Johann Wolfgang von Goethe's Faust, Part Two (1832) famously features an alchemically-created homunculus.[15] Here, the character of Homunculus embodies the quest of a pure spirit to be born into mortal form, contrasting Faust's desire to shed his mortal body to become pure spirit. The alchemical idea that the soul is not imprisoned in the body, but instead may find its brightest state as it passes through the material plane is central to the character.The homunculus legend, Frankenstein and Faust have continued to influence works in the twentieth and twenty-first century. The theme has been used not only in fantasy literature, but also to illuminate social topics. For instance, the British children's writers Mary Norton and Rumer Godden used homunculus motifs in their work, expressing various post-war anxieties about refugees, persecution of minorities in war, and the adaptation of these minorities to a "big" world.[17] W. Somerset Maugham's 1908 novel The Magician utilises the concept of the homunculus as an important plot element. David H. Keller’s short story "A Twentieth-Century Homunculus" (1930) describes the creation of homunculi on an industrial scale by a pair of misogynists. Likewise, Sven Delblanc’s The Homunculus: A Magic Tale (1965) addresses misogyny and the Cold War industrial-military complexes of the Soviet Union and NATO.The eye listens to the green rays which draw its peripheries bright of life, the electric energy resembles this lighting yet only due to a green filter and an under exposure of the edges of the image.The homunsculus and the metallic embryon is the fairy Tale of the Green Snacke
At the UCSF Decoding the Brain Academy last night, Dr. Tomasz Nowakowski plotted the progress of neurons sequenced over time, including the project planned for 2025. It has been following a Moore’s Law-like exponential curve for a decade now. So, we should have a sequence of every one of the 86 billion neurons in a human brain by 2032, and maybe all the glial cells too.
Why sequence every cell? The genetic makeup varies, as does the methylation. On the left, you can see clustering analysis of 121 different cell types in the thalamus alone. Out neurons are very different, and they vary over time. I was reminded of an amazing discovery Ed Boyden of MIT shared with me — they found HIV-like encodings being expressed in human neurons. This might be a transposon-like viral vector for horizontal gene transfer in the brain. This is a controversial finding, partially because it is difficult to detect the signal from the noise of the delta from the human reference genome, which is still Craig Venter. I asked Ed how many neuron types does he suspect we’ll find? “An infinite number. They are all different.”
When we asked Nowakowski about the compute capacity of a neuron, he lit up with excitement. By analogy to our machine learning neural nets with back prop, we now know that our neurons don’t just adjust weights at the synapse. Firing-feedback adjusts the weights in all of the ~1000 inputs embedded in the dendrite of each neuron. This is called synaptic tagging, and it serves as an overlay to the relaxation back to a nominal rate of firing, a process that is not fully understood.
From the other speakers on stage, left to right:
• Shawn Hervey-Jumper: in 50 years of neurosurgery advances, we have added just 4 months to expected lifespan
• Mercedes Paredes: in the pre-natal and infant brain (up to 6 months), neurons migrate great distances (1-10cm) by sending out an axon and pulling the neuron cell body along, a sequence of push and pulls. For a sense of scale, if the neuron was a car, it is like driving across America. How do they navigate over these distances?
• Christine Liu: We can keep brain tissues alive for weeks now (for glass probe insertion into neural cell bodies). Learning how to juggle can increase cortical thickness by 3%.
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Another from last Thursdays visit to Canary Wharf Winter Lights Festival, this time it's 'Neuron' by Juan Fuentes.
This for me was one of the moer interesting installations but without my tripod I've not really been able to do it justice.
Click here to see more photos from Canary Wharf : www.flickr.com/photos/darrellg/albums/72177720298516472
From Canarywharf.com, "This newly commissioned installation is inspired by the intricate network of neural connections in the human brain. The vast three-dimensional structure composed of thousands of luminous filaments that interweave and intricately connect, aims to make the incredibly complex concept of the human brain into a tangible, and beautiful art object. Each filament represents a neuron, and their interconnection symbolizes neuronal synapses, where the transmission of electrical and chemical signals take place."
© D.Godliman
nEUROn et Rafale M en vol au-dessus du porte-avions Charles de Gaulle.
Essais à la mer afin d'étudier l'utilisation d'un drone de combat dans un contexte naval.
© Dassault Aviation - A. Pecchi
Neuronal cells were cultured in a microfluidic device with channels to induce guidance of axons. We load the device with nanorods which penetrate into the cells and we study how those rods move inside the axons. Cells have been fixed and plastified with resin (thin layer plastification, procedure developed in our lab) such that both the rods and the cells are preserved and visible. In fact we can distinguish between the penetrating rods and those which just stay outside the cell.
Courtesy of Dr. Francesca Santoro , Stanford University - Chemistry Department
Image Details
Instrument used: Helios NanoLab
Voltage: 5kV
Detector: BSE
I posted my two "Strangers in the Atacama" Sets to quite a few groups a while back. I will not post all the images again tothose groups, but I am re-posting this one image to a few selective groups along with an invitation to read the story again because I have expanding the ending quite a bit and have taken the story further. For new groups I have just joined, you get the whole treatment ;>)
For folks who did not have a chance see the two sets and read the story the first time, I invite you to have a look. The begins on the set thumbnail page: www.flickr.com/photos/retrorocketrick/sets/72157627217616...
The treatment effects that were not in the original unaltered image (which are included in this set), are mine, for better or for worse, and were done in Photoshop Elements 7.
There was at least 10 layers to this scene, and about 8 hrs work in this one image, before I hit the "merge" button. (whew!)
I would really enjoy substantive comment. So often we, as Flickr members, post only one or two words about someone's efforts, or posts one of those pre-made "awards" which really says nothing, nor provides any human feedback.
I challenge those that take the time to read these words, to come up with some subnative comment(s) that says "Wowzer" about you and your imagination. If you would like to expand, or add your own thoughts to the story just post it in the thread's comment box. Sooooo here is a chance to dust off your creative neurons and let them roam freely around in your three-shelled cranium. Come on, don't be chicken!
Reading the story on the set thumbnail page can be rather tedious so I would suggest you copy and paste both parts into whatever word processor you are using. Print a copy use it, as you look at the applicable set images.
Thanks,
~retrorocketrick
**************** By the way:
--The background desert is the Atacama in Peru/Chile. - been there and have the tee shirt to prove it!
--A lot of the building were taken from my photos of Casa Mila in Barcelona.
-- The cliff I lifted from a photo I took in the Paracas National Reserve in Peru
-- and the lone survivor, sitting there licking his wounded hand, was lifted from an photo I took in the Mangrover Forests of Peru.
--The shack was in the original photo. In this first set, at the end I have include photos of our actual train ride through the Atacama.
In Atacama Desert of Chile
The octopus (plural octopuses) is a soft-bodied, eight-limbed mollusc of the order Octopoda (/ɒkˈtɒpədə/, ok-TO-pə-də). Around 300 species are recognised, and the order is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, the octopus is bilaterally symmetric with two eyes and a beak, with its mouth at the center point of the eight limbs.[a] The soft body can rapidly alter its shape, enabling octopuses to squeeze through small gaps. They trail their eight appendages behind them as they swim. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates.
Octopuses inhabit various regions of the ocean, including coral reefs, pelagic waters, and the seabed; some live in the intertidal zone and others at abyssal depths. Most species grow quickly, mature early, and are short-lived. In most species, the male uses a specially adapted arm to deliver a bundle of sperm directly into the female's mantle cavity, after which he becomes senescent and dies, while the female deposits fertilised eggs in a den and cares for them until they hatch, after which she also dies. Strategies to defend themselves against predators include the expulsion of ink, the use of camouflage and threat displays, the ability to jet quickly through the water and hide, and even deceit. All octopuses are venomous, but only the blue-ringed octopuses are known to be deadly to humans.
Octopuses appear in mythology as sea monsters like the Kraken of Norway and the Akkorokamui of the Ainu, and probably the Gorgon of ancient Greece. A battle with an octopus appears in Victor Hugo's book Toilers of the Sea, inspiring other works such as Ian Fleming's Octopussy. Octopuses appear in Japanese erotic art, shunga. They are eaten and considered a delicacy by humans in many parts of the world, especially the Mediterranean and the Asian seas.
ETYMOLOGY AND PLURALISATION
The scientific Latin term octopus was derived from Ancient Greek ὀκτώπους, a compound form of ὀκτώ (oktō, "eight") and πούς (pous, "foot"), itself a variant form of ὀκτάπους, a word used for example by Alexander of Tralles (c. 525–605) for the common octopus. The standard pluralised form of "octopus" in English is "octopuses"; the Ancient Greek plural ὀκτώποδες, "octopodes" (/ɒkˈtɒpədiːz/), has also been used historically. The alternative plural "octopi" is considered grammatically incorrect because it wrongly assumes that octopus is a Latin second declension "-us" noun or adjective when, in either Greek or Latin, it is a third declension noun.
Fowler's Modern English Usage states that the only acceptable plural in English is "octopuses", that "octopi" is misconceived, and "octopodes" pedantic; the latter is nonetheless used frequently enough to be acknowledged by the descriptivist Merriam-Webster 11th Collegiate Dictionary and Webster's New World College Dictionary. The Oxford English Dictionary lists "octopuses", "octopi", and "octopodes", in that order, reflecting frequency of use, calling "octopodes" rare and noting that "octopi" is based on a misunderstanding. The New Oxford American Dictionary (3rd Edition, 2010) lists "octopuses" as the only acceptable pluralisation, and indicates that "octopodes" is still occasionally used, but that "octopi" is incorrect.
ANATOMY AND PHYSIOLOGY
SIZE
The giant Pacific octopus (Enteroctopus dofleini) is often cited as the largest known octopus species. Adults usually weigh around 15 kg, with an arm span of up to 4.3 m. The largest specimen of this species to be scientifically documented was an animal with a live mass of 71 kg. Much larger sizes have been claimed for the giant Pacific octopus: one specimen was recorded as 272 kg with an arm span of 9 m. A carcass of the seven-arm octopus, Haliphron atlanticus, weighed 61 kg and was estimated to have had a live mass of 75 kg. The smallest species is Octopus wolfi, which is around 2.5 cm and weighs less than 1 g.
EXTERNAL CHARACTERISTICS
The octopus is bilaterally symmetrical along its dorso-ventral axis; the head and foot are at one end of an elongated body and function as the anterior (front) of the animal. The head includes the mouth and brain. The foot has evolved into a set of flexible, prehensile appendages, known as "arms", that surround the mouth and are attached to each other near their base by a webbed structure. The arms can be described based on side and sequence position (such as L1, R1, L2, R2) and divided into four pairs. The two rear appendages are generally used to walk on the sea floor, while the other six are used to forage for food; hence some biologists refer to the animals as having six "arms" and two "legs". The bulbous and hollow mantle is fused to the back of the head and is known as the visceral hump; it contains most of the vital organs. The mantle cavity has muscular walls and contains the gills; it is connected to the exterior by a funnel or siphon. The mouth of an octopus, located underneath the arms, has a sharp hard beak.
The skin consists of a thin outer epidermis with mucous cells and sensory cells, and a connective tissue dermis consisting largely of collagen fibres and various cells allowing colour change. Most of the body is made of soft tissue allowing it to lengthen, contract, and contort itself. The octopus can squeeze through tiny gaps; even the larger species can pass through an opening close to 2.5 cm in diameter. Lacking skeletal support, the arms work as muscular hydrostats and contain longitudinal, transverse and circular muscles around a central axial nerve. They can extend and contract, twist to left or right, bend at any place in any direction or be held rigid.
The interior surfaces of the arms are covered with circular, adhesive suckers. The suckers allow the octopus to anchor itself or to manipulate objects. Each sucker is usually circular and bowl-like and has two distinct parts: an outer shallow cavity called an infundibulum and a central hollow cavity called an acetabulum, both of which are thick muscles covered in a protective chitinous cuticle. When a sucker attaches to a surface, the orifice between the two structures is sealed. The infundibulum provides adhesion while the acetabulum remains free, and muscle contractions allow for attachment and detachment.
The eyes of the octopus are large and are at the top of the head. They are similar in structure to those of a fish and are enclosed in a cartilaginous capsule fused to the cranium. The cornea is formed from a translucent epidermal layer and the slit-shaped pupil forms a hole in the iris and lies just behind. The lens is suspended behind the pupil and photoreceptive retinal cells cover the back of the eye. The pupil can be adjusted in size and a retinal pigment screens incident light in bright conditions.Some species differ in form from the typical octopus body shape. Basal species, the Cirrina, have stout gelatinous bodies with webbing that reaches near the tip of their arms, and two large fins above the eyes, supported by an internal shell. Fleshy papillae or cirri are found along the bottom of the arms, and the eyes are more developed.
CIRCULATORY SYSTEM
Octopuses have a closed circulatory system, in which the blood remains inside blood vessels. Octopuses have three hearts; a systemic heart that circulates blood around the body and two branchial hearts that pump it through each of the two gills. The systemic heart is inactive when the animal is swimming and thus it tires quickly and prefers to crawl. Octopus blood contains the copper-rich protein haemocyanin to transport oxygen. This makes the blood very viscous and it requires considerable pressure to pump it around the body; octopuses' blood pressures can exceed 75 mmHg. In cold conditions with low oxygen levels, haemocyanin transports oxygen more efficiently than haemoglobin. The haemocyanin is dissolved in the plasma instead of being carried within blood cells, and gives the blood a bluish colour.
The systemic heart has muscular contractile walls and consists of a single ventricle and two atria, one for each side of the body. The blood vessels consist of arteries, capillaries and veins and are lined with a cellular endothelium which is quite unlike that of most other invertebrates. The blood circulates through the aorta and capillary system, to the vena cavae, after which the blood is pumped through the gills by the auxiliary hearts and back to the main heart. Much of the venous system is contractile, which helps circulate the blood.
RESPIRATION
Respiration involves drawing water into the mantle cavity through an aperture, passing it through the gills, and expelling it through the siphon. The ingress of water is achieved by contraction of radial muscles in the mantle wall, and flapper valves shut when strong circular muscles force the water out through the siphon. Extensive connective tissue lattices support the respiratory muscles and allow them to expand the respiratory chamber. The lamella structure of the gills allows for a high oxygen uptake, up to 65% in water at 20 °C. Water flow over the gills correlates with locomotion, and an octopus can propel its body when it expels water out of its siphon.
The thin skin of the octopus absorbs additional oxygen. When resting, around 41% of an octopus's oxygen absorption is through the skin. This decreases to 33% when it swims, as more water flows over the gills; skin oxygen uptake also increases. When it is resting after a meal, absorption through the skin can drop to 3% of its total oxygen uptake.
DIGESTION AND EXCRETION
The digestive system of the octopus begins with the buccal mass which consists of the mouth with its chitinous beak, the pharynx, radula and salivary glands. The radula is a spiked, muscular tongue-like organ with multiple rows of tiny teeth. Food is broken down and is forced into the oesophagus by two lateral extensions of the esophageal side walls in addition to the radula. From there it is transferred to the gastrointestinal tract, which is mostly suspended from the roof of the mantle cavity by numerous membranes. The tract consists of a crop, where the food is stored; a stomach, where food is ground down; a caecum where the now sludgy food is sorted into fluids and particles and which plays an important role in absorption; the digestive gland, where liver cells break down and absorb the fluid and become "brown bodies"; and the intestine, where the accumulated waste is turned into faecal ropes by secretions and blown out of the funnel via the rectum.
During osmoregulation, fluid is added to the pericardia of the branchial hearts. The octopus has two nephridia (equivalent to vertebrate kidneys) which are associated with the branchial hearts; these and their associated ducts connect the pericardial cavities with the mantle cavity. Before reaching the branchial heart, each branch of the vena cava expands to form renal appendages which are in direct contact with the thin-walled nephridium. The urine is first formed in the pericardial cavity, and is modified by excretion, chiefly of ammonia, and selective absorption from the renal appendages, as it is passed along the associated duct and through the nephridiopore into the mantle cavity.
NERVOUS SYSTEM AND SENSES
The octopus (along with cuttlefish) has the highest brain-to-body mass ratios of all invertebrates; it is also greater than that of many vertebrates. It has a highly complex nervous system, only part of which is localised in its brain, which is contained in a cartilaginous capsule. Two-thirds of an octopus's neurons are found in the nerve cords of its arms, which show a variety of complex reflex actions that persist even when they have no input from the brain. Unlike vertebrates, the complex motor skills of octopuses are not organised in their brain via an internal somatotopic map of its body, instead using a nonsomatotopic system unique to large-brained invertebrates.
Like other cephalopods, octopuses can distinguish the polarisation of light. Colour vision appears to vary from species to species, for example being present in O. aegina but absent in O. vulgaris. Researchers believe that opsins in the skin can sense different wavelengths of light and help the creatures choose a coloration that camouflages them, in addition to light input from the eyes. Other researchers hypothesise that cephalopod eyes in species which only have a single photoreceptor protein may use chromatic aberration to turn monochromatic vision into colour vision, though this sacrifices image quality. This would explain pupils shaped like the letter U, the letter W, or a dumbbell, as well as explaining the need for colourful mating displays.
Attached to the brain are two special organs called statocysts (sac-like structures containing a mineralised mass and sensitive hairs), that allow the octopus to sense the orientation of its body. They provide information on the position of the body relative to gravity and can detect angular acceleration. An autonomic response keeps the octopus's eyes oriented so that the pupil is always horizontal. Octopuses may also use the statocyst to hear sound. The common octopus can hear sounds between 400 Hz and 1000 Hz, and hears best at 600 Hz.
Octopuses also have an excellent sense of touch. The octopus's suction cups are equipped with chemoreceptors so the octopus can taste what it touches. Octopus arms do not become tangled or stuck to each other because the sensors recognise octopus skin and prevent self-attachment.
The arms contain tension sensors so the octopus knows whether its arms are stretched out, but this is not sufficient for the brain to determine the position of the octopus's body or arms. As a result, the octopus does not possess stereognosis; that is, it does not form a mental image of the overall shape of the object it is handling. It can detect local texture variations, but cannot integrate the information into a larger picture. The neurological autonomy of the arms means the octopus has great difficulty learning about the detailed effects of its motions. It has a poor proprioceptive sense, and it knows what exact motions were made only by observing the arms visually.
Ink sac
The ink sac of an octopus is located under the digestive gland. A gland attached to the sac produces the ink, and the sac stores it. The sac is close enough to the funnel for the octopus to shoot out the ink with a water jet. Before it leaves the funnel, the ink passes through glands which mix it with mucus, creating a thick, dark blob which allows the animal to escape from a predator. The main pigment in the ink is melanin, which gives it its black colour. Cirrate octopuses lack the ink sac.
LIFECYCLE
REPRODUCTION
Octopuses are gonochoric and have a single, posteriorly-located gonad which is associated with the coelom. The testis in males and the ovary in females bulges into the gonocoel and the gametes are released here. The gonocoel is connected by the gonoduct to the mantle cavity, which it enters at the gonopore. An optic gland creates hormones that cause the octopus to mature and age and stimulate gamete production. The gland may be triggered by environmental conditions such as temperature, light and nutrition, which thus control the timing of reproduction and lifespan.
When octopuses reproduce, the male uses a specialised arm called a hectocotylus to transfer spermatophores (packets of sperm) from the terminal organ of the reproductive tract (the cephalopod "penis") into the female's mantle cavity. The hectocotylus in benthic octopuses is usually the third right arm, which has a spoon-shaped depression and modified suckers near the tip. In most species, fertilisation occurs in the mantle cavity.
The reproduction of octopuses has been studied in only a few species. One such species is the giant Pacific octopus, in which courtship is accompanied, especially in the male, by changes in skin texture and colour. The male may cling to the top or side of the female or position himself beside her. There is some speculation that he may first use his hectocotylus to remove any spermatophore or sperm already present in the female. He picks up a spermatophore from his spermatophoric sac with the hectocotylus, inserts it into the female's mantle cavity, and deposits it in the correct location for the species, which in the giant Pacific octopus is the opening of the oviduct. Two spermatophores are transferred in this way; these are about one metre (yard) long, and the empty ends may protrude from the female's mantle. A complex hydraulic mechanism releases the sperm from the spermatophore, and it is stored internally by the female.
About forty days after mating, the female giant Pacific octopus attaches strings of small fertilised eggs (10,000 to 70,000 in total) to rocks in a crevice or under an overhang. Here she guards and cares for them for about five months (160 days) until they hatch. In colder waters, such as those off of Alaska, it may take as much as 10 months for the eggs to completely develop. The female aerates the eggs and keeps them clean; if left untended, many eggs will not hatch. She does not feed during this time and dies soon afterwards. Males become senescent and die a few weeks after mating.
The eggs have large yolks; cleavage (division) is superficial and a germinal disc develops at the pole. During gastrulation, the margins of this grow down and surround the yolk, forming a yolk sac, which eventually forms part of the gut. The dorsal side of the disc grows upwards and forms the embryo, with a shell gland on its dorsal surface, gills, mantle and eyes. The arms and funnel develop as part of the foot on the ventral side of the disc. The arms later migrate upwards, coming to form a ring around the funnel and mouth. The yolk is gradually absorbed as the embryo develops.
Most young octopuses hatch as paralarvae and are planktonic for weeks to months, depending on the species and water temperature. They feed on copepods, arthropod larvae and other zooplankton, eventually settling on the ocean floor and developing directly into adults with no distinct metamorphoses that are present in other groups of mollusc larvae. Octopus species that produce larger eggs – including the southern blue-ringed, Caribbean reef, California two-spot, Eledone moschata and deep sea octopuses – do not have a paralarval stage, but hatch as benthic animals similar to the adults.In the argonaut (paper nautilus), the female secretes a fine, fluted, papery shell in which the eggs are deposited and in which she also resides while floating in mid-ocean. In this she broods the young, and it also serves as a buoyancy aid allowing her to adjust her depth. The male argonaut is minute by comparison and has no shell.
LIFESPAN
Octopuses have a relatively short life expectancy; some species live for as little as six months. The giant Pacific octopus, one of the two largest species of octopus, may live for as much as five years. Octopus lifespan is limited by reproduction: males can live for only a few months after mating, and females die shortly after their eggs hatch. The larger Pacific striped octopus is an exception, as it can reproduce multiple times over a life of around two years. Octopus reproductive organs mature due to the hormonal influence of the optic gland but result in the inactivation of their digestive glands, typically causing the octopus to die from starvation. Experimental removal of both optic glands after spawning was found to result in the cessation of broodiness, the resumption of feeding, increased growth, and greatly extended lifespans. It has been proposed that the naturally short lifespan may be functional to prevent rapid overpopulation.
DISTRIBUTION AND HABITAT
Octopuses live in every ocean, and different species have adapted to different marine habitats. As juveniles, common octopuses inhabit shallow tide pools. The Hawaiian day octopus (Octopus cyanea) lives on coral reefs; argonauts drift in pelagic waters. Abdopus aculeatus mostly lives in near-shore seagrass beds. Some species are adapted to the cold, ocean depths. The spoon-armed octopus (Bathypolypus arcticus) is found at depths of 1,000 m, and Vulcanoctopus hydrothermalis lives near hydrothermal vents at 2,000 m. The cirrate species are often free-swimming and live in deep-water habitats. Although several species are known to live at bathyal and abyssal depths, there is only a single indisputable record of an octopus in the hadal zone; a species of Grimpoteuthis (dumbo octopus) photographed at 6,957 m. No species are known to live in fresh water.
BEHAVIOUR AND ECOLOGY
Most species are solitary when not mating, though a few are known to occur in high densities and with frequent interactions, signaling, mate defending and eviction of individuals from dens. This is likely the result of abundant food supplies combined with limited den sites. The larger Pacific striped octopus however is social, living in groups of up to 40 individuals that share dens. Octopuses hide in dens, which are typically crevices in rocky outcrops or other hard structures, though some species burrow into sand or mud. Octopuses are not territorial but generally remain in a home range; they may leave the area in search of food. They can use navigation skills to return to a den without having to retrace their outward route. They are not known to be migratory.
Octopuses bring captured prey back to the den where they can eat it safely. Sometimes the octopus catches more prey than it can eat, and the den is often surrounded by a midden of dead and uneaten food items. Other creatures, such as fish, crabs, molluscs and echinoderms, often share the den with the octopus, either because they have arrived as scavengers, or because they have survived capture. Octopuses rarely engage in interspecific cooperative hunting with fish as their partners. They regulate the species composition of the hunting group - and the behavior of their partners - by punching them.
FEEDING
Nearly all octopuses are predatory; bottom-dwelling octopuses eat mainly crustaceans, polychaete worms, and other molluscs such as whelks and clams; open-ocean octopuses eat mainly prawns, fish and other cephalopods. Major items in the diet of the giant Pacific octopus include bivalve molluscs such as the cockle Clinocardium nuttallii, clams and scallops and crustaceans such as crabs and spider crabs. Prey that it is likely to reject include moon snails because they are too large and limpets, rock scallops, chitons and abalone, because they are too securely fixed to the rock.
A benthic (bottom-dwelling) octopus typically moves among the rocks and feels through the crevices. The creature may make a jet-propelled pounce on prey and pull it towards the mouth with its arms, the suckers restraining it. Small prey may be completely trapped by the webbed structure. Octopuses usually inject crustaceans like crabs with a paralysing saliva then dismember them with their beaks. Octopuses feed on shelled molluscs either by forcing the valves apart, or by drilling a hole in the shell to inject a nerve toxin. It used to be thought that the hole was drilled by the radula, but it has now been shown that minute teeth at the tip of the salivary papilla are involved, and an enzyme in the toxic saliva is used to dissolve the calcium carbonate of the shell. It takes about three hours for O. vulgaris to create a 0.6 mm hole. Once the shell is penetrated, the prey dies almost instantaneously, its muscles relax, and the soft tissues are easy for the octopus to remove. Crabs may also be treated in this way; tough-shelled species are more likely to be drilled, and soft-shelled crabs are torn apart.
Some species have other modes of feeding. Grimpoteuthis has a reduced or non-existent radula and swallows prey whole. In the deep-sea genus Stauroteuthis, some of the muscle cells that control the suckers in most species have been replaced with photophores which are believed to fool prey by directing them towards the mouth, making them one of the few bioluminescent octopuses.
LOCOMOTION
Octopuses mainly move about by relatively slow crawling with some swimming in a head-first position. Jet propulsion or backwards swimming, is their fastest means of locomotion, followed by swimming and crawling. When in no hurry, they usually crawl on either solid or soft surfaces. Several arms are extended forwards, some of the suckers adhere to the substrate and the animal hauls itself forwards with its powerful arm muscles, while other arms may push rather than pull. As progress is made, other arms move ahead to repeat these actions and the original suckers detach. During crawling, the heart rate nearly doubles, and the animal requires ten or fifteen minutes to recover from relatively minor exercise.
Most octopuses swim by expelling a jet of water from the mantle through the siphon into the sea. The physical principle behind this is that the force required to accelerate the water through the orifice produces a reaction that propels the octopus in the opposite direction. The direction of travel depends on the orientation of the siphon. When swimming, the head is at the front and the siphon is pointed backwards, but when jetting, the visceral hump leads, the siphon points towards the head and the arms trail behind, with the animal presenting a fusiform appearance. In an alternative method of swimming, some species flatten themselves dorso-ventrally, and swim with the arms held out sideways, and this may provide lift and be faster than normal swimming. Jetting is used to escape from danger, but is physiologically inefficient, requiring a mantle pressure so high as to stop the heart from beating, resulting in a progressive oxygen deficit.
Cirrate octopuses cannot produce jet propulsion and rely on their fins for swimming. They have neutral buoyancy and drift through the water with the fins extended. They can also contract their arms and surrounding web to make sudden moves known as "take-offs". Another form of locomotion is "pumping", which involves symmetrical contractions of muscles in their webs producing peristaltic waves. This moves the body slowly.
In 2005, Adopus aculeatus and veined octopus (Amphioctopus marginatus) were found to walk on two arms, while at the same time mimicking plant matter. This form of locomotion allows these octopuses to move quickly away from a potential predator without being recognised. A study of this behaviour led to the suggestion that the two rearmost appendages may be more accurately termed "legs" rather than "arms". Some species of octopus can crawl out of the water briefly, which they may do between tide pools while hunting crustaceans or gastropods or to escape predators. "Stilt walking" is used by the veined octopus when carrying stacked coconut shells. The octopus carries the shells underneath it with two arms, and progresses with an ungainly gait supported by its remaining arms held rigid.
INTELLIGENCE
Octopuses are highly intelligent; the extent of their intelligence and learning capability are not well defined. Maze and problem-solving experiments have shown evidence of a memory system that can store both short- and long-term memory. It is not known precisely what contribution learning makes to adult octopus behaviour. Young octopuses learn nothing from their parents, as adults provide no parental care beyond tending to their eggs until the young octopuses hatch.
In laboratory experiments, octopuses can be readily trained to distinguish between different shapes and patterns. They have been reported to practise observational learning, although the validity of these findings is contested. Octopuses have also been observed in what has been described as play: repeatedly releasing bottles or toys into a circular current in their aquariums and then catching them. Octopuses often break out of their aquariums and sometimes into others in search of food. They have even boarded fishing boats and opened holds to eat crabs. The veined octopus collects discarded coconut shells, then uses them to build a shelter, an example of tool use.
CAMOUFLAGE AND COLOUR CHANGE
Octopuses use camouflage when hunting and to avoid predators. To do this they use specialised skin cells which change the appearance of the skin by adjusting its colour, opacity, or reflectivity. Chromatophores contain yellow, orange, red, brown, or black pigments; most species have three of these colours, while some have two or four. Other colour-changing cells are reflective iridophores and white leucophores. This colour-changing ability is also used to communicate with or warn other octopuses.
Octopuses can create distracting patterns with waves of dark coloration across the body, a display known as the "passing cloud". Muscles in the skin change the texture of the mantle to achieve greater camouflage. In some species, the mantle can take on the spiky appearance of algae; in others, skin anatomy is limited to relatively uniform shades of one colour with limited skin texture. Octopuses that are diurnal and live in shallow water have evolved more complex skin than their nocturnal and deep-sea counterparts.
A "moving rock" trick involves the octopus mimicking a rock and then inching across the open space with a speed matching the movement in the surrounding water, allowing it to move in plain sight of a predator.
DEFENCE
Aside from humans, octopuses may be preyed on by fishes, seabirds, sea otters, pinnipeds, cetaceans, and other cephalopods. Octopuses typically hide or disguise themselves by camouflage and mimicry; some have conspicuous warning coloration (aposematism) or deimatic behaviour. An octopus may spend 40% of its time hidden away in its den. When the octopus is approached, it may extend an arm to investigate. 66% of Enteroctopus dofleini in one study had scars, with 50% having amputated arms. The blue rings of the highly venomous blue-ringed octopus are hidden in muscular skin folds which contract when the animal is threatened, exposing the iridescent warning. The Atlantic white-spotted octopus (Callistoctopus macropus) turns bright brownish red with oval white spots all over in a high contrast display. Displays are often reinforced by stretching out the animal's arms, fins or web to make it look as big and threatening as possible.
Once they have been seen by a predator, they commonly try to escape but can also use distraction with an ink cloud ejected from the ink sac. The ink is thought to reduce the efficiency of olfactory organs, which would aid evasion from predators that employ smell for hunting, such as sharks. Ink clouds of some species might act as pseudomorphs, or decoys that the predator attacks instead.
When under attack, some octopuses can perform arm autotomy, in a manner similar to the way skinks and other lizards detach their tails. The crawling arm may distract would-be predators. Such severed arms remain sensitive to stimuli and move away from unpleasant sensations. Octopuses can replace lost limbs.
Some octopuses, such as the mimic octopus, can combine their highly flexible bodies with their colour-changing ability to mimic other, more dangerous animals, such as lionfish, sea snakes, and eels.
PATHOGENS AND PARASITES
The diseases and parasites that affect octopuses have been little studied, but cephalopods are known to be the intermediate or final hosts of various parasitic cestodes, nematodes and copepods; 150 species of protistan and metazoan parasites have been recognised. The Dicyemidae are a family of tiny worms that are found in the renal appendages of many species; it is unclear whether they are parasitic or are endosymbionts. Coccidians in the genus Aggregata living in the gut cause severe disease to the host. Octopuses have an innate immune system, and the haemocytes respond to infection by phagocytosis, encapsulation, infiltration or cytotoxic activities to destroy or isolate the pathogens. The haemocytes play an important role in the recognition and elimination of foreign bodies and wound repair. Captive animals have been found to be more susceptible to pathogens than wild ones. A gram-negative bacterium, Vibrio lentus, has been found to cause skin lesions, exposure of muscle and death of octopuses in extreme cases.
EVOLUTION
The scientific name Octopoda was first coined and given as the order of octopuses in 1818 by English biologist William Elford Leach, who classified them as Octopoida the previous year. The Octopoda consists of around 300 known species and were historically divided into two suborders, the Incirrina and the Cirrina. However, more recent evidence suggests that Cirrina are merely the most basal species and are not a unique clade. The incirrate octopuses (the majority of species) lack the cirri and paired swimming fins of the cirrates. In addition, the internal shell of incirrates is either present as a pair of stylets or absent altogether.
FOSSIL HISTORY AND PHYLOGENY
Cephalopods have existed for 500 million years and octopus ancestors were in the Carboniferous seas 300 million years ago. The oldest known octopus fossil is Pohlsepia, which lived 296 million years ago. Researchers have identified impressions of eight arms, two eyes, and possibly an ink sac. Octopuses are mostly soft tissue, and so fossils are relatively rare. Octopuses, squids and cuttlefish belong to the clade Coleoidea. They are known as "soft-bodied" cephalopods, lacking the external shell of most molluscs and other cephalopods like the nautiloids and the extinct Ammonoidea. Octopuses have eight limbs like other coleoids but lack the extra specialised feeding appendages known as tentacles which are longer and thinner with suckers only at their club-like ends. The vampire squid (Vampyroteuthis) also lacks tentacles but has sensory filaments.
The cladograms are based on Sanchez et al., 2018, who created a molecular phylogeny based on mitochondrial and nuclear DNA marker sequences.
RNA EDITING
Octopuses and other coleoid cephalopods are capable of greater RNA editing (which involves changes to the nucleic acid sequence of the primary transcript of RNA molecules) than any other organisms. Editing is concentrated in the nervous system and affects proteins involved in neural excitability and neuronal morphology. More than 60% of RNA transcripts for coleoid brains are recoded by editing, compared to less than 1% for a human or fruit fly. Coleoids rely mostly on ADAR enzymes for RNA editing, which requires large double-stranded RNA structures to flank the editing sites. Both the structures and editing sites are conserved in the coleoid genome and the mutation rates for the sites are severely hampered. Hence, greater transcriptome plasticity has come at the cost of slower genome evolution. High levels of RNA editing do not appear to be present in more basal cephalopods or other molluscs.
RELATIONSHIP TO HUMANS
CULTURAL REFERENCES
Ancient seafaring people were aware of the octopus, as evidenced by certain artworks and designs. For example, a stone carving found in the archaeological recovery from Bronze Age Minoan Crete at Knossos (1900–1100 BC) has a depiction of a fisherman carrying an octopus. The terrifyingly powerful Gorgon of Greek mythology has been thought to have been inspired by the octopus or squid, the octopus itself representing the severed head of Medusa, the beak as the protruding tongue and fangs, and its tentacles as the snakes. The Kraken are legendary sea monsters of giant proportions said to dwell off the coasts of Norway and Greenland, usually portrayed in art as a giant octopus attacking ships. Linnaeus included it in the first edition of his 1735 Systema Naturae. One translation of the Hawaiian creation myth the Kumulipo suggests that the octopus is the lone survivor of a previous age. The Akkorokamui is a gigantic octopus-like monster from Ainu folklore.
A battle with an octopus plays a significant role in Victor Hugo's book Travailleurs de la mer (Toilers of the Sea), relating to his time in exile on Guernsey. Ian Fleming's 1966 short story collection Octopussy and The Living Daylights, and the 1983 James Bond film were partly inspired by Hugo's book.
Japanese erotic art, shunga, includes ukiyo-e woodblock prints such as Katsushika Hokusai's 1814 print Tako to ama (The Dream of the Fisherman's Wife), in which an ama diver is sexually intertwined with a large and a small octopus. The print is a forerunner of tentacle erotica. The biologist P. Z. Myers noted in his science blog, Pharyngula, that octopuses appear in "extraordinary" graphic illustrations involving women, tentacles, and bare breasts.
Since it has numerous arms emanating from a common centre, the octopus is often used as a symbol for a powerful and manipulative organisation, company, or country.
DANGER
Octopuses generally avoid humans, but incidents have been verified. For example, a 2.4-metre Pacific octopus, said to be nearly perfectly camouflaged, "lunged" at a diver and "wrangled" over his camera before it let go. Another diver recorded the encounter on video.
All species are venomous, but only blue-ringed octopuses have venom that is lethal to humans. Bites are reported each year across the animals' range from Australia to the eastern Indo-Pacific Ocean. They bite only when provoked or accidentally stepped upon; bites are small and usually painless. The venom appears to be able to penetrate the skin without a puncture, given prolonged contact. It contains tetrodotoxin, which causes paralysis by blocking the transmission of nerve impulses to the muscles. This causes death by respiratory failure leading to cerebral anoxia. No antidote is known, but if breathing can be kept going artificially, patients recover within 24 hours. Bites have been recorded from captive octopuses of other species; they leave swellings which disappear in a day or two.
FISHERIES AND CUISINE
Octopus fisheries exist around the world with total catches varying between 245,320 and 322,999 metric tons from 1986 to 1995. The world catch peaked in 2007 at 380,000 tons, and fell by a tenth by 2012. Methods to capture octopuses include pots, traps, trawls, snares, drift fishing, spearing, hooking and hand collection. Octopus is eaten in many cultures and is a common food on the Mediterranean and Asian coasts. The arms and sometimes other body parts are prepared in various ways, often varying by species or geography. Live octopuses are eaten in several countries around the world, including the US. Animal welfare groups have objected to this practice on the basis that octopuses can experience pain. Octopuses have a food conversion efficiency greater than that of chickens, making octopus aquaculture a possibility.
IN SCIENCE AND TECHNOLOGY
In classical Greece, Aristotle (384–322 BC) commented on the colour-changing abilities of the octopus, both for camouflage and for signalling, in his Historia animalium: "The octopus ... seeks its prey by so changing its colour as to render it like the colour of the stones adjacent to it; it does so also when alarmed." Aristotle noted that the octopus had a hectocotyl arm and suggested it might be used in sexual reproduction. This claim was widely disbelieved until the 19th century. It was described in 1829 by the French zoologist Georges Cuvier, who supposed it to be a parasitic worm, naming it as a new species, Hectocotylus octopodis. Other zoologists thought it a spermatophore; the German zoologist Heinrich Müller believed it was "designed" to detach during copulation. In 1856 the Danish zoologist Japetus Steenstrup demonstrated that it is used to transfer sperm, and only rarely detaches.
Octopuses offer many possibilities in biological research, including their ability to regenerate limbs, change the colour of their skin, behave intelligently with a distributed nervous system, and make use of 168 kinds of protocadherins (humans have 58), the proteins that guide the connections neurons make with each other. The California two-spot octopus has had its genome sequenced, allowing exploration of its molecular adaptations. Having independently evolved mammal-like intelligence, octopuses have been compared to hypothetical intelligent extraterrestrials. Their problem-solving skills, along with their mobility and lack of rigid structure enable them to escape from supposedly secure tanks in laboratories and public aquariums.
Due to their intelligence, octopuses are listed in some countries as experimental animals on which surgery may not be performed without anesthesia, a protection usually extended only to vertebrates. In the UK from 1993 to 2012, the common octopus (Octopus vulgaris) was the only invertebrate protected under the Animals (Scientific Procedures) Act 1986. In 2012, this legislation was extended to include all cephalopods in accordance with a general EU directive.
Some robotics research is exploring biomimicry of octopus features. Octopus arms can move and sense largely autonomously without intervention from the animal's central nervous system. In 2015 a team in Italy built soft-bodied robots able to crawl and swim, requiring only minimal computation. In 2017 a German company made an arm with a soft pneumatically controlled silicone gripper fitted with two rows of suckers. It is able to grasp objects such as a metal tube, a magazine, or a ball, and to fill a glass by pouring water from a bottle.
WIKIPEDIA
Close-up of neurons in a mouse with the neurodegenerative disease Niemann-Pick type C1. A major way to assess the impact of a potential therapeutic on the central nervous system is to assess cerebellar pathology in mice.
Credit: I. Williams, National Institute of Child Health and Human Development, NIH