Wednesday, January 30, 2008

SomaSimple Pain Consensus

Lately Luke Rickards DO, a moderator at SomaSimple, initiated this consensus. Several people contributed their thoughts and eventually agreed on the following, reproduced here in its entirety:
"Behind the scenes at SomaSimple the moderators study continuously, deal with the issues inherent to our task and decide together how we can advance our mission of sharing relevant and rational information about therapy theory and practice.

Recently Luke Rickards listed ten things he felt we now know about the nature of painful sensation. It has since been modified and referenced and you’ll see the document below. We have had an intricate and prolonged conversation about each point, and now invite your questions and commentary. The following list has been compiled in an effort to present you with succinct points derived from contemporary pain related research so that you may better understand the view points of the moderators and many of the regular posters at SomaSimple. The list is subject to change as our understanding improves.

As with all statements born of scientific reasoning these are provisional, but we feel at least a few will stand the test of time. For those interested in gaining a more detailed understanding of the generalized items on the list, we recommend reading the material referenced in the bibliography.


The Moderators"

Nothing Simple - Ten Steps to Understanding Manual and Movement Therapies for Pain

1. Pain is a category of complex experiences, not a single sensation produced by a single stimulus.

2. Nociception (warning signals from body tissues) is neither necessary nor sufficient to produce pain. In other words, pain can occur in the absence of tissue damage.

3. A pain experience may be induced or amplified by both actual and potential threats.

4. A pain experience may involve a composite of sensory, motor, autonomic, endocrine, immune, cognitive, affective and behavioural components. Context and meaning are paramount in determining the eventual output response.

5. The brain maps peripheral and central neural processing into each of these components at multiple levels. Therapeutic input at a single level may be sufficient to resolve a threat response.

6. Therapies that are most likely to be successful in treating non-pathological pain are those that address unhelpful cognitions and fear concerning the meaning of pain, introduce movement in a non-threatening internal and external context, and/or convince the brain that the threat has been resolved.

7. Manual and movement therapies may affect peripheral and central neural processes at various stages:
- transduction of nociception at peripheral sensory receptors
- transmission of nociception in the peripheral nervous system
- transmission of nociception in the central nervous system
- processing and modulation in the brain

8. The corrective physiological mechanisms responsible for resolution are inherent. In non-pathological pain states a therapist need only provide an appropriate environment for their expression.

9. There is little correlation between tissue length, form or symmetry and the prevalence of pain. Manually applied forces will almost never directly result in clinically relevant and lasting change in tissue length, form or symmetry. The effects of manual therapy are more plausibly regarded as the result of reflexive neurophysiological responses.

10. Neuromuscular reconditioning is best initiated after near or full resolution of the pain experience. Conditioning for the purpose of fitness and function or to prompt exercise-induced analgesia can be performed concurrently but threat and nocebo should be considered. Conditioning should be conducted in the knowledge that there is no substantial evidence that posture, muscular weakness or weight are risk factors for neuromusculoskeletal pain.


Pain: The Science of Suffering - Patrick Wall
The Challenge of Pain - Patrick Wall, Ronald Melzack
Explain Pain - David Butler, Lorimer Moseley
The Sensitive Nervous System - David Butler
Phantoms in the Brain - V. S. Ramachandran
Topical Issues in Pain Vol's 1-5 - Louis Giffiord (ed)
The Feeling of What Happens - Antonio Damasio
Clinical Neurodynamics - Michael Shacklock
Eyal Lederman - The Science and Practice of Manual Therapy

Research articles:
Melzack R. Pain and the neuromatrix in the brain. J Dental Ed. 2001;65:1378-82.
Craig AD. Pain mechanisms: Labeled lines versus convergence in central processing. Ann Rev Neurosci. 2003;26:130.
Craig AD. How do you feel? Interoception: the sense of the physiological condition of the body. Nature Rev Neurosci. 2002;3:655-66.
Henderson LA, Gandevia SC, Macefield VG. Somatotopic organization of the processing of muscle and cutaneous pain in the left and right insula cortex: A single-trial fMRI study. Pain. 2007;128:20-30.
Olausson H, Lamarre Y, Backlund H, Morin C, Wallin BG, Starck G, Ekholm S, Strigo I, Worsley K, Vallbo AB, Bushnell MC. Unmyelinated tactile afferents signal touch and project to insular cortex. Nature Neurosci. 2002;5:900–904.
Moseley GL. A pain neuromatrix approach to patients with chronic pain. Manual Ther. 2003;8:130-40.
Moseley GL. Unravelling the barriers to reconceptualisation of the problem in chronic pain: The actual and perceived ability of patients and health professionals to understand the neurophysiology. J Pain. 2003;4:184-89.
Moseley GL, Arntz A. The context of a noxious stimulus affects the pain it evokes. Pain. 2007;133(1-3):64-71.
Moseley, GL, Nicholas, MK and Hodges, PW. A randomized controlled trial of intensive neurophysiology education in chronic low back pain. Clin J Pain. 2004;20:324-30.
Crombez G, Vlaeyen JWS, Heuts PH et al. Pain-related fear is more disabling than pain itself. Evidence on the role of pain-related fear in chronic back pain disability. Pain. 1999;80:329-40.
Zusman M. Forebrain-mediated sensitization of central pain pathways: 'non-specific' pain and a new image for manual therapy. Manual Ther. 2002;7:80-88.
Dorko B. The analgesia of movement: Ideomotor activity and manual care. J Osteopathic Med. 2003;6:93-95.
Threlkeld AJ. The effects of manual therapy on connective tissue. Phys Ther. 1992;72:893-902.
Lederman E. The myth of core stability. Retrieved at:

Sunday, January 27, 2008

The Fish With Arm Bones

Tiktaalik rosae is the name Neil Shubin's team gave a fossil they found in the Canadian Arctic a couple years ago. Shubin's book, Your Inner Fish, describes the dig and the excitement that surrounded the discovery of what Shubin calls a "fishapod".

The book is a great read - full of evolutionary and embryologic connections. You'll learn where spines and skeletons come from, what genes we share with our insect and worm relations, why hernias and knee injuries have come to plague the human species. You'll learn all about how gill arches turned into inner ear bones and throat cartilages, how head bones form, why the development of a mobile neck (present in Tiktaalik) was a revolution in evolution (it freed the upper limbs to do one thing while the head did another).

I was hoping for a fuller examination of the evolution of the nervous system, but alas, such an examination was beyond the scope of this book apparently. There are a few tidbits on brainstem function and central pattern generators, and why the phrenic and vagus nerves emerge so soon and dangle dangerously outside the spinal column before reaching their destinations.

It is hard to put this book down if you have any sort of interest in the human body, whether it is a third-person or first-person interest. It will leave the reader feeling an integrated part of all nature through time. I recommend reading it together with Into the Cool (much of which is available free online in the link provided) and dazzle gradually, both of which are co-written by Dorion Sagan. For more about the evolution of the nervous system itself, Up From Dragons is a fairly good read, yet another Dorion Sagan co-write. (How can you tell I'm a big Dorion Sagan fan?)

Saturday, January 26, 2008

Hippocampus, theta waves and movement VII

Vanderwolf wanted to sort out what would happen with direct brain stimulation as opposed to merely observing slow wave in conjunction with spontaneous behaviors.

Vanderwolf (p. 33) is careful to point out that:
"..the fact hippocampal rhythmical slow waves occur in close correlation with certain patterns of movement does not necessarily mean that hippocampal activity has a role in causing the movement. It is well recognized that correlation does not prove causation."
He goes on to say,
"It is apparent that some motor patterns, including the various forms of locomotion, head movements, spontaneous changes in posture, and manipulating objects with the forelimbs, are invariably accompanied by hippocampal rhythmical slow wave activity, while other motor patterns, including alert immobility, licking, biting, chewing, face-washing, and such gross motor patterns as the startle response and the writhing-stretching movements of giving birth, are generally accompanied by an irregular pattern of hippocampal activity. These hippocampo-behavior relations occur during both spontaneous behavior and the behavior elicited by hypothalamic stimulation. The two different classes of behavior cannot be distinguished on the basis of extent of muscular activity, degree of arousal, stress, or excitement and have no particular relation to the often stressed polarity of learning and instinct. How should all of this be interpreted and what should these classes of behavior be called?"

To me this is the crux of the matter, and why I'm busy reading this book. To continue:
"Animal behaviorists, following a proposal by Wallace Craig in 1918, often distinguish appetitive from consummatory behavior. Walking toward food is an appetitive behavior; eating the food, a consummatory behavior. Prior to Craig's suggestion, Charles Sherrington (1906) had suggested a distinction betwen precurrent reactions (similar to Craig's appetitive behavior) and consummatory reactions, stressing the dependence of the first type on distance receptors (vision, audition, olfaction) and of the second type on contact receptors (touch, taste). However, John Hughlings Jackson, an English neurologist writing well before either Sherrington or Craig, had suggested a continuum in the basis of motor control ranging from most voluntary to most automatic or reflexive... Consequently, I began to refer to behaviors consistently accompanied by hippocampal rhythmical slow wave as "voluntary" and behaviors not consistently accompanied by this wave form as "automatic." However, the attempt to apply Jacksonian terminology to hippocampal-behavioral relations was not welcomed."

Instead he categorized behaviors into Type I and Type II.
Here is the list:

Type I (slow wave hippocampal activity always present):
walking, running, swimming, rearing, jumping, digging, manipulating objects with forelimbs, isolated movements of head or of one limb, shifts of posture.
Related terms: voluntary, appetitive, instrumental, purposive, operant, or "theta" behavior.

Type II (irregular wave activity):
alert immobility in any posture, licking, chewing, chattering teeth, sneezing, startle response, vocalization, shivering, tremor, face-washing, scratching fur, pelvic thrusting, ejaculation, defecation, urination, piloerection.
Related terms: autonomic, reflexive, consummatory, respondent, "non-theta" behavior.

So, after all this investigating of this interesting material I don't think I'm any closer to knowing where ideomotor movement might fit, but at least I know more about hippocampal wave associated movement than I used to.

Tuesday, January 22, 2008

Hippocampus, theta waves and movement VI

Throughout the 70's a lot of research was done that tried to show a relation between hippocampal activity and memory. Vanderwolf says,
"Much of this we simply ignored, hoping that such research would die out as more and more people became aware of the relation between hippocampal activity and motor activity."
A paper was published in Science suggesting that hippocampal slow waves were transmitted to the neocortex during the formation of a memory trace. Vanderwolf writes:
"We knew that the neocortex generates large amplitude rhythmical 7-9 Hz waves of its own" independent of the hippocampus, which "unlike the hippocampal waves, are driven by inputs from the thalamus and occur spontaneously at times during waking repeating the experiments and collecting additional data Peter and I were able to show that the results reported in the Science paper were due to a)failure to distinguish two very different waveforms which happen to overlap in frequency, b) failure to take account of the relation between cerebral activity and motor activity."
They published their results in 1982. Similarly, Vanderwolf and a colleague deconstructed a paper which proposed a link between hippocampal waves and sniffing behavior, and published their own findings in 1992. They noted that furthermore, hippocampal wave activity was not associated with alert immobility, mating behavior, giving birth, or fighting. Rather, it was found during walking or running, or during the carrying of pups - any time locomotion occurred.

Monday, January 21, 2008

Hippocampus, theta waves and movement V

In 1957 a paper appeared (Scoville and Milner) "claiming that hoppocampal lesions produced amnesia." In a paper two years later, Vanderwolf says:
"Grastyan and his colleagues reported that hippocampal rhythmical slow waves were characteristic of the early stages of learning when the cats displayed prominent orientating reactions (the what-is-it reactions of Pavlov) but that both the orienting responses and the associated rhythmical slow waves disappeared when the learned behavior had become well seemed to me that a different interpretation was more probable. Early in training, extensive exploratory movements such as walking, rearing, and head movement are likely to occur but later when the learned behavior is well-established, unnecessary motor activity tends to disappear."

It seemed researchers were trying to link hippocampus with learning and memory. Vanderwolf didn't buy this. He had already noted the sorts of movements that were associated with hippocampal slow wave formation, and reasoned that
"if one were to compare the electromyographic activity of somatic muscles during spontaneous behavior before and after training, extensive changes would, no doubt, be observed but this would not mean that muscles are directly involved in learning and memory. Similarly, training-induced changes in hippocampal activity may be a consequence of a role played by the hippocampus in control of motor activity."

Vanderwolf devised a way to test his hunch, providing data that showed hippocampal slow wave present during continuous running or walking. If the animal stopped moving the hippocampal rhythmical waves were always interrupted. Long-continued practice didn't necessarily result in disappearance or even any change at all in the rhythmical slow waves of the hippocampus. His data re-confirmed that hippocampal slow wave activity was present during "varying untrained spontaneous motor acts".

More about this to follow.

Friday, January 18, 2008

Hippocampus, theta waves and movement IV

In part III I brought some of the info from Vanderwolf's book to do with movement, types of movement, and their association with hippocampal wave function. On p. 16 he says:
".. in 1962 (we) had shown that rhythmical waves could occur in the thalamus and hippocampus slightly in advance of overt motor activity. ...I had no accurate means of determining the precise instant of movement onset and.. spontaneous movements do not have an abrupt onset. Spontaneous walking, for example, is usually preceded by small head movements and adjustments in posture (intention movements). What was need was an abrupt transition from complete immobility to vigorous gross movement of the type that is consistently accompanied by hippocampal waves."
To solve this problem he designed a box with a metal floor into which a rat could be placed and a small shock delivered to its feet, part of a training process teaching them to jump out of the box; i.e., shock was not part of the experimental design, just the jump-from-inside-the-box training.
"..a trained rat could be placed gently on the floor, standing on its hind legs. After a delay of several seconds during which the rat stood motionless, the hind legs would extend suddenly, propelling the rat to the top of the box. A movement-sensing device mounted on the box recorded the onset of this jump with an accuracy of a few milliseconds."
Vanderwolf found that rhythmical waves of 6-7 Hz could occur several seconds prior to the jump. Beginning about a second before the jump the frequency increased to 8-12 Hz, peaking at jump initiation, continuing until the rat landed on the "safe" shelf.
"The data from this experiment suggested that the hippocampus might have some role in both planning and the performance of a motor pattern. It also suggested a problem which subsequently became a major focus of my research. If the rhythmical waves of the hippocampus are related to motor activity, how is it possible that these waves can be present during relatively long intervals (several seconds) when a rat is absolutely motionless?"
Meanwhile, in a nearby lab the hippocampus of New Zealand white rabbits showed rhythmical activity being elicited with visual and auditory input only, no visible motor activity, something not noted in rats.

REM sleep presented another exception to the idea that hippocampal rhythmical activity was associated with movement, and was noted by Vanderwolf in the late 60's.
"The onset of REM sleep in a rat is always associated with an utter collapse of any pre-existing muscle tone. Thus, if a rat falls asleep in a crouched sitting posture, as they sometimes do, the onset of REM sleep is associated with the body slumping down limply on the floor. Despite this, bursts of muscular twitches occur periodically in the limbs, trunk, and especially in the vibrissae. Rhythmical slow waves occurred in the hippocampus throughout an episode of REM sleep, with higher frequency waves occurring during the muscular twitches than during the inter-twitch intervals. An interpretation of this curious phenomenon was suggested by research originating with Otto Pompeiano of the University of Pisa.It appears that brain motor systems generally are in a state of high activity during REM sleep but that overt expression of this activity is blocked by a powerful inhibition of spinal motor neurons and of reflex afferents to those neurons. Consequently, instead of running, jumping, etc. the animal lies limply on the floor, twitching slightly. The hippocampal record then is related to motor activity during REM sleep as well as during waking."
At this point Vanderwolf teamed with Bob Sainsbury and two students, Brian Bland and Ian Whishaw, to continue the work at U. of Western Ont.

Next: hippocampal slow waves, learning and instinctive behavior.

Thursday, January 17, 2008


I read on Mindblog this morning about an essay by a Danish science writer named Tor Nørretranders, called Permanent Reincarnation. It's one of the loveliest things I've ever read at Edge. So lovely that I'm going to replicate vast swathes of it here.
"My body is not like a typical material object, a stable thing. It is more like a flame, a river or an eddie. Matter is flowing through it all the time. The constituents are being replaced over and over again.

A chair or a table is stable because the atoms stay where they are. The stability of a river stems from the constant flow of water through it."

That sounds very Tao-like.. talk of rivers, never standing in the same river twice, etc.. Nørretranders goes on:
"98 percent of the atoms in the body are replaced every year. 98 percent! Water molecules stays in your body for two weeks (and for an even shorter time in a hot climate), the atoms in your bones stays there for a few months. Some atoms stay for years. But almost not one single atom stay with you in your body from cradle to grave.

What is constant in you is not material. An average person takes in 1.5 ton of matter every year as food, drinks and oxygen. All this matter has to learn to be you. Every year. New atoms will have to learn to remember your childhood.

These numbers has been known for half a century or more, mostly from studies of radioactive isotopes. Physicist Richard Feynman said in 1955: "Last week's potatoes! They now can remember what was going on in your mind a year ago."

But why is this simple insight not on the all-time Top 10 list of important discoveries? Perhaps because it tastes a little like spiritualism and idealism? Only the ghosts are for real? Wandering souls?

But digital media now makes it possible to think of all this in a simple way. The music I danced to as a teenager has been moved from vinyl-LPs to magnetic audio tapes to CDs to Pods and whatnot. The physical representation can change and is not important — as long as it is there. The music can jump from medium to medium, but it is lost if it does not have a representation. This physics of information was sorted out by Rolf Landauer in the 1960'ies. Likewise, out memories can move from potato-atoms to burger-atoms to banana-atoms. But the moment they are on their own, they are lost.

We reincarnate ourselves all the time. We constantly give our personality new flesh. I keep my mental life alive by making it jump from atom to atom. A constant flow. Never the same atoms, always the same river. No flow, no river. No flow, no me.

This is what I call permanent reincarnation: Software replacing its hardware all the time. Atoms replacing atoms all the time. Life. This is very different from religious reincarnation with souls jumping from body to body (and souls sitting out there waiting for a body to take home in).

There has to be material continuity for permanent reincarnation to be possible. The software is what is preserved, but it cannot live on its own. It has to jump from molecule to molecule, always in carnation.

I have changed my mind about the stability of my body: It keeps changing all the time. Or I could not stay the same."

This is a lovely meditation on being a speck of conscious awareness in a physicality, even if that "I" is just an illusion arising from that very physicality whose business seems to be to recycle material. Who says atheists can't enjoy the occasional spiritual perspective on existence once in awhile? It's heartening, calming, comforting, beautiful. It gives one a sense of being part of the whole, not a separated aberration. I like the idea that life is a river that I am permanently part of.. Sometimes it may feel necessary to focus, like if I were white water rafting in a hailstorm, but most of the time it feels like I'm on my back in an inner tube, just floating along and watching the banks pass by on a warm sunny day. Not so bad. Parts will all end up somewhere just as they do now anyway, endlessly recycled.

Here is his bilingual blog. Thank you Tor.

Sunday, January 13, 2008

Hippocampus, theta waves and movement III

A description of the following rat behaviors and accompanying rhythms appears next.

Sleep to waking:

1. Sleep: neocortex waves went from low voltage fast activity to large amplitude, irregular slow waves.

2. Startle out of sleep with a noise: rat
"would leap to its feet, startled, its head up, eyes wide open, then stand motionless."
Large slow waves of the neocortex were replaced by low voltage higher frequency record (neocortical activation) but no rhythmical waves from hippocampus, instead a pattern of irregular waves with low amplitude.

From this Vanderwolf concluded that
"the rhythmical hippocampal waves had nothing to do with arousal or alerting; they were specifically related to a class of movements that did not include the startle response."

During movement:

3. In the waking rat: sensory stimuli generally elicited hippocampal rhythmical slow activity only if they also elicited a certain type of motor activity.
".. a great variety of visual, auditory, tactile and olfactory stimuli elicited both hippocampal rhythmical slow activity and a behavioral response that included head movements, stepping and locomotion."

4. Rats hung vertically by their front paws: No hippocampal activity was recorded while they just hung there, front paws clutched over the top of a vertical board.
"Rhythmical waves always appeared, however, when a rat pulled itself up, climbing to the top of the board."

Vanderwolf concluded that rhythmical hippocampal waves accompany certain phasic movements not static muscular exertion. Furthermore, maintenance of an immobile standing posture on two legs or four, was not associated with rhythmical slow hippocampal activity.


5. Grooming: Rat sits up on hind legs and uses front paws to rub its mouth, face, eyes and whiskers, followed by nibbling of own flanks, hind legs, abdomen. Movements are vigorous, but generally not accompanied by rhythmical hippocampal waves. By contrast, while resting, even just a small movement of one forepaw was regularly accompanied by rhythmical hippocampal waves.

Conclusion: two qualitatively distinct classes of behavior: one accompanied by waves and one not.

6. Grooming: occasional bursts of clear rhythmical waves lasting a second or two at most, occurred during long grooming sessions. They were accompanied by changes in posture, transitions from the rat paying attention to/grooming one area of the body, to paying attention to/grooming another area.

Conclusion: rat grooming behavior consists of two kinds of movement, 1) stereotyped licking, biting fur, rubbing of forepaws over face, without hippocampal slow wave; 2) changes in posture, accompanied by rhythmical slow activity in the hippocampus.

7. Grooming behavior, plus startle: Two possible reactions: rat becomes immobile (freezing behavior) without hippocampal slow wave accompaniment, however, if head movements or locomotion were chosen by the rat, rhythmical waves would appear.

Eating and drinking:

8. Approach to food, snatching it, running off with it: continuous rhythmical waves were recorded.

9. During chewing and handling of food with forepaws: Rhythmical hippocampal activity was present at the onset of eating a large food pellet, but as the pellet got smaller so did the hippocampal activity.

10. Sniffing behavior: vigorous sniffs with small head movements - no associated slow rhythmical wave from hippocampus associated.

11. Approach to/retreat from water dish was accompanied by rhythmical hippocampal waves but not the act of drinking itself.

12. Rhythmical hippocampal waves were found to have no specific relation to exploratory behavior in general sense. On the other hand, changing posture of head while eating or changing posture while grooming are well-practiced and are accompanied by slow wave activity.

Next, Vanderwolf looked deeper at premotor activity.

Friday, January 11, 2008

Hippocampus, theta waves and movement II

The first problem Vanderwolf tackled was to get a clear reading, using rats. Finally he placed one electrode "near the surface of the alveus or in the stratum oriens and a second electrode in the vicinity of the hippocampal fissure." These are small bits of hippocampal gross anatomy. He then got wave potentials that occurred in opposite phase and that were easy to distinguish from neocortical waves.

He says:
"When, at last, adequate slow wave signals from the hippocampus were recorded, their relation to behavior became very obvious. Gross movements such as walking, struggling to escape from my hand, or rearing up on the hind legs were invariably accompanied by rhythmical potentials potentials of about 8-9 Hz but a more irregular pattern punctuated at irregular intervals by large spike-like potentials (sharp waves), occurred whenever the rat stood still. However, it also became apparent that a number of smaller movements such as turning the head, changing posture while resting, or moving a forepaw in isolation, were also reliably accompanied by rhythmical waves but both the amplitude and frequency (6-7 Hz) of these waves was less than it was during walking or struggling."

This information was obtained on rats, but humans and rats share mammalian brain structures. Walking sounds like a good thing to do for the hippocampus - make big waves so the 10,000 new baby neurons that form in there every day get some big wave stimulation.

Monday, January 07, 2008

Hippocampus, theta waves and movement

I've been reading another book about this topic, An Odyssey Through the Brain, Behavior and the Mind, by C.H. Vanderwolf, found by following a trail from the Buzsáki book I was absorbed in all fall, Rhythms of the Brain. I will bring a summary of info here, direct from this book, about which behaviors with which Vanderwolf found theta rhythm associated and those he didn't. But first, an introduction:

Vanderwolf was born and raised in rural Alberta which provided him much opportunity to observe animals in nature, on his way to becoming one of the world's foremost theta rhythm researchers. This book is the story of his research, partly autobiographical but mostly about what he discovered, and includes a defense of his anti-"mentalist" stance in research on behavior. In the 1964 he began his own research on rhythmical hippocampal activity. He says (p.3):
"The program of research that I had in mind was based on certain philosophical presuppositions. Most investigators in the brain-behaviour field, both in 1964 and at present, assume that the ultimate problem for neuroscience is to provide an explanation of the human mind. More specifically, this is usually taken to mean discovering the neural basis of consciousness and its subprocesses such as perception, attention, memory, cognition, emotion, motivation, etc. I was very suspicious of this entire enterprise and gradually came to believe that the traditional categories of the mind did not provide a valid natural subdivision of different brain functions."

He wanted to approach research from nature's own direction (p. 4):
"During my career as a student, I had taken several laboratory courses in mammalian physiology, pharmacology and biochemistry and had been much attracted by the idea that a living animal can be regarded as an enormously complex machine whose operations are all potentially explicable in physical and chemical terms. Most of the brain, it seemed to me, was dedicated to the control of motor activity (behavior). If the entire forebrain and midbrain are surgically removed from an animal (leaving an island of the hypothalamus to permit operation of the pituitary gland), respiratory, cardiovascular, digestive, and excretory functions proceed almost normally but spontaneous behaviour is abolished. Such a decerebrate animal can no longer walk about, feed itself, groom itself, seek shelter, avoid enemies, find a mate, or care for its young. Therefore, it must be that what the intact brain does is generate all of these (and more) varied behavioural performances. To say that a decerebrate animal has no behaviour because it is unconscious seemed to me to be no explanation at all but merely a restatement of the problem in more obscure terms."

Thursday, January 03, 2008

Not so SAD anymore

After going into detail about SAD, and now being comfortably back from it, in retrospect I see that it was a good thing to go consciously through that whole process in wide-awake observant detail; in retrospect it looks like it was just a simple mental molt, something that needn't have too big a deal made over it in the future. In me, like in many other kinds of mammals, it seems to be a light dependent or seasonal molt.

All sorts of animals - insects and birds and reptiles and even monkeys and apes molt: why should we humans not have the pleasure? Just because we no longer have a fluffy pelt? It's something that can be ignored but why would we want to do that if we are trying to learn to live in harmony with our own deep rhythms?

Like many other things we humans have sublimated or evolved new strategies for, our molting is now experienced mainly at a symbolic level, I suppose. It may feel intense at the time, and confusing, but like any other sort of molt, SAD leaves the human organism renewed with a shiny fresh mental coat, fewer mental parasites attached, more room to breathe, more comfortable emotionally. There will always be a sense of vulnerability associated, and some raw emotional processing to do, but really, it's necessary once in awhile, and it sure feels good once it's over with.

Tuesday, January 01, 2008

Scholarpedia online neuroscience encyclopedia

I've added a new link to the menu on the right, to Scholarpedia's Encylopedia of Computational Neuroscience. (I learned about this through a blogpost by Mo, at Neurophilosophy, a blog I check every day. Thank you Mo.)

I look forward to more articles going up over there, but for now, this one on grid cells by Edvard Moser pertains to much of the reading/blogging I've been doing since September. I feel that at least part of my job as a human primate social groomer is to read and understand and strive to make more sense of what I do in light of all this lovely information.

Here are a few more that Mo has already preselected:
1. Mirror neurons by Giacomo Rizzolatti
2. Synesthesia by V.S. Ramachandran
3. Neural correlates of consciousness by Chris Koch

Here are a few more I checked out:

1. Synfire chains Definition:
"a feed-forward network of neurons with many layers (or pools). Each neuron in one pool feeds many excitatory connections to neurons in the next pool, and each neuron in the receiving pool is excited by many neurons in the previous pool. When activity in such a cascade of pools is arranged like a volley of spikes propagating synchronously from pool to pool it is called a synfire chain."

2. LTD, or long-term depression Definition:
"Long-term depression (LTD) is a weakening of a synapse after a short series of presynaptic action potentials or asynchronous presynaptic and postsynaptic activity. LTD is distinguished in homosynaptic LTD, heterosynaptic LTD and associative LTD."
(I think this is more along the lines of synaptic inhibition. I'm sure there must have been a good reason to change the name to depression, although I can't imagine what it might have been.)

3. Brain
Seems like it would be something one could slide past, yet it's definitely worth a read.
"Function: The intimate relation of the brain to the sense organs points to the brain’s essential role as an information handling device. Meaningful events to which the animal reacts are but rarely signaled by a single sense organ. More commonly it is a combination of information from different sensory modalities that gives away the aggressor, or the prey, or the sexual partner, or the dangerous cliff etc. Thus the brain is there to make concepts out of sensations, at a higher level of abstraction. It is not only the different senses that contribute to the formation of concepts. Equally important, the monitoring of motor behavior, both in its planning and in its execution, provides crucial information necessary for the correct interpretation of any situation signaled by the senses. All of this requires a brain."

4. Intrinsic plasticity Definition:
"the persistent modification of a neuron’s intrinsic electrical properties by neuronal or synaptic activity. It is mediated by changes in the expression level or biophysical properties of ion channels in the membrane, and can affect such diverse processes as synaptic integration, subthreshold signal propagation, spike generation, spike backpropagation, and meta-plasticity. The function of intrinsic plasticity in behaving animals is uncertain but there is experimental evidence for several distinct roles: as part of the memory engram itself, as a regulator of synaptic plasticity underlying learning and memory, and as a component of homeostatic regulation.
It is important to note that intrinsic plasticity is distinct from synaptic plasticity"

5. High-conductance state

6. Various systems models: Ermentrout-Kopell Canonical Model (aka theta model); XPPAUT; FitzHugh-Nagumo Model; Morris-Lecar Model; Rall model;

7. Cortical memory

8. Synergetics Definition:
"Synergetics deals with material or immaterial systems, composed of, in general, many individual parts (Haken 2004, see also Springer series in Synergetics, about 80 volumes). It focuses its attention on the spontaneous, i.e. self-organized emergence of new qualities which may be structures, processes or functions."

9. Various networks: Hopfield Network; Kohonen network;

10. Neuron

11. Reward, reward signals

12. Stomatogastric ganglion (of crustaceans, sort of a mini-brain)

13. Thalamus Excerpt:
"A consideration of the complexity of thalamic cell and circuit properties puts a lie to the old notion that thalamus represents a simple, machine-like relay of information to cortex. We can now be certain of two major concepts to replace this. The first is that the thalamus represents a last bottleneck of information flow, providing a convenient substrate to influence that flow. This is achieved by the many modulatory pathways that innervate relay cells to influence relay function in numerous ways. One detailed above is the burst/tonic transition in the firing mode of relay cells, but this is just the tip of the iceberg. We need much more information about the many ways thalamic circuitry controls information flow to cortex.
The second point is that the role of thalamus is not limited to getting information to cortex in the first place, which is the role of first order relays, but also continues to function in the higher order cortico-thalamo-cortical pathways, thereby providing an essential, ongoing function for cortical processing. This dramatically alters long-standing views of cortical processing, and we need to know much more about the different roles of cortico-thalamo-cortical versus direct corticocortical pathways in cortical functioning."

14. Binding by Synchrony Excerpt:
"One of the coordinating mechanisms appears to be the synchronization of neuronal activity by phase locking of self-generated network oscillations."

15. Fast Oscillations

16. Blindsight

17. Up and down states

There are about 500 more articles coming along or already written. They are listed alphabetically by author (first names, only up to "L" for some strange reason) here.