Recent replies to "What´s the Real Role of Inhibition?"

Reply from chris lofting

chris lofting — Fri, 16 May 2008 13:06:47 -0000

Alfredo,

We move here into the form of primary emotions grounded in our primate natures and so shareable with other neuron-dependent, emotion-driven, life forms as compared to the development of secondary emotions in tandem with what those emotions depend upon for their existence in humans, a sense of SELF.

The literature indicates that that sense of self develops in the first 24 months of life and is trainable as such from then onwards (and so the development to varying degrees of guilt)

Consciousness overall appears to come out of regulation and on into mediation dynamics, the realm of the asymmetric mediating the anti-symmetric (parts focus) and the symmetric (wholes focus). The CONTROL factor brings out the inhibiting nature of consciousness on our primate instincts and brings out the parallel processing of our primate natures and our conscious, unique being, natures. This gets us into a focus on delayed gratification over immediate and so of planning and pre-empting outcomes as compared to ‘instinctive’ reactions.

Delay requires inhibition and as such a degree of suffering is considered acceptable for the sake of the long term, pleasurable gain later on – even to the extent where such a perspective grounds certain religious schoolsc and includes individual suffering for the sake of the collective.

This focus on delay and so allowing for reflection etc moves us into second order cybernetics and so enter the realm of Varela, Luhmann etc covering the dynamics of such regardless of local form of expression (e.g. the neurology) in that the regulation factor applies at all scales, be it of the neuron or of a human collective.

The association of delay and consciousness maps to the realm of the asymmetric and out of that the generation of language – and so more inhibition allows for precision in the ultimate form of syntax where the rigour present, and so the inhibiting overall of choices, brings out precison in communication. This indicates that the path of transcendence is through language and so through inhibition that can then lead to excitation.

Our primary emotions are more magnitudinal and so scalar and lacking the vector quality needed for precision in communication and so in development of consciousness.c Secondary emotions, covering the inhibiting nature of guilt, bring out the overall regulation of behaviour by consciousness and so the developent of consciousness from a mediating/regulating realm reflected in delay dynamics and so the dynamics of soma and synaptic gap as compared to dendrites and axon.

IOW stimulus-response is a dendrite-to-axon dynamic covering instincts etc (and then collectives of neurons working as if one neuron but with high bandwidth); only with hormone densities in the synaptic gaps and synchronisation/recruitment dynamics with the soma do we introduce delay and so cover inhibition and the benefits of.

Reply from Alfredo Pereira Jr

Alfredo Pereira Jr — Fri, 16 May 2008 11:45:03 -0000

Dear Chris:

Discoveries about the promiscuity of opposite feelings/emotions in the context of brain activity bring new and unexpected possibilities for psychological theorizing, as in the context of your IDM model or based in classical philosophy (e.g., Hegelian dialectics).
The most interesting aspect, in my view, is that the conversion of opposites is related to the role of inhibitory processes in the brain. This kind of phenomenon implies that inhibition is not just the negation (suppression) of activity that generates feelings/emotions, but also is creative or generative of feelings/emotions.

Best

Alfredo

Reply from chris lofting

chris lofting — Thu, 15 May 2008 23:33:18 -0000

Alfredo, in the IDM material I bring out this link in the form of an emotion link covering passion in the form of sexual love and grief as opposite sites of the same coin – passion.

In the same material is the focus of sexual love and anger sharing the same space in that they both stem for communicating intent in dealing with context – in particular to replace the existing with one’s own – either by eradication (anger) or replication (sex).

These primitive emotions become refined into richer formats (e.g. self-respect, singlemindedness of anger, or discernment from grief etc)

Reply from Alfredo Pereira Jr

Alfredo Pereira Jr — Thu, 15 May 2008 20:22:06 -0000

A recent paper in Nature Neuroscience (see Abstract below) is important for this forum.
Alfredo

Nature Reviews Neuroscience 9, 314-320 (April 2008) | doi:10.1038/nrn2333

A common neurobiology for pain and pleasure
Siri Leknes & Irene Tracey

Abstract
Pain and pleasure are powerful motivators of behaviour and have historically been considered opposites. Emerging evidence from the pain and reward research fields points to extensive similarities in the anatomical substrates of painful and pleasant sensations. Recent molecular-imaging and animal studies have demonstrated the important role of the opioid and dopamine systems in modulating both pain and pleasure. Understanding the mutually inhibitory effects that pain and reward processing have on each other, and the neural mechanisms that underpin such modulation, is important for alleviating unnecessary suffering and improving well-being.

Source: Nature Neuroscience

Reply from Alfredo Pereira Jr

Alfredo Pereira Jr — Tue, 06 May 2008 03:01:29 -0000

[I am resending this message with some corrections]

Dear Sergio:

Since Jazz involves so rich mental (and corporal) activity, I am glad that
neuroscience is beginning to study brain activity of musicians as they play, but the
referenced study seems to be too simplistic in associating musical creativity with
a decrease in neuronal inhibition. One inference that could be made is that
inhibition is related to obeying rules. However, this interpretation is
mistaken, since Jazz has its own rules as you mentioned. The second possibility is that the decrease of inhibition is part of the creativity process (following rules while recombining patterns into a new musical form).

Best Regards from cold Botucatu

Alfredo

Reply from Sergio Basbaum

Sergio Basbaum — Fri, 02 May 2008 15:34:31 -0000

Dears Chris & Alfredo & all,
I’d just like to make a comment regarding the affirmation that Jazz is “free of rules”, which I think does not consider what really is to play jazz.
As a cultural form firmly stabilished by means of its practice in a variety of approaches, jazz may be everything but purely free: it has its own rules, whose origins can be traced in the melting of African oral traditions and European musical material (chords, scales, etc…). The emergency of what can be called its “modern” form can be found in the 1940s, with the so called “Bebob” generation, which in fact stabilished the rules for playing a music that would promove improvisation, would combine individual expression with collective effort, would—most of all—“swing”, and would be theoretically and technically sophisticated. Thus, it has clear structures and an amount of technical and theoretical knowledge over which a musician must have domain in order to play. So, for its practioners, certainly there are clear rules, and all varieties of forms and styles clearly dialogue with this model, either reinforcing its strenghth or being a deviation of it. (to show that art is not “freedom” in the terms common-sense believes it is would demand another discussion…).

However, I do think Jazz is an excelent case through which to discuss consciousness, cognition and conscious behavior, since to play this game (let’s assume it as a game for a minute), one has to deal with a lot of very sophisticated superior and linguistic tasks (scales, phrasing, chords), while at the same time doing it very fast, interacting with the actions of the group, taking decisions which are expected not only to be “correct” but to reach a certain aesthetic level , and also carry on certain emotion, thus being expression. Also, one has to deal with tempo, rythmic impositions, thus involving motor functions and the body as a whole, otherwise there’s no swing. I think Jazz, for the amazing complexity of its rules and the seemingly freeness of its final aspect is a real great situation to discuss embodyness, representation, decision-making, integration of linguistic features, memory, projection of action in time, etc… As a jazz player myself, I know very well that to feel free playing demands a lot of complex expertise. It’s a really great field to deal with cognition.

all the best for you all from rainy Sao Paulo

Sergio

Reply from chris lofting

chris lofting — Fri, 25 Apr 2008 11:03:45 -0000

How come the last bit of my post had lines placed through the text!?

Oh well – just to add a point – whatever is developed to protect is open to exploitation and at the same time whatever is developed for exploitation elicits a focus on protection from such!

Socially, if X is exploited but that exploitation is then ‘banned’ so protection systems develop in competition to ‘refine’ the banning mechanism!

When protection systems become refined so exploitation emerges in defeating such systems – etc etc etc – and this at ALL scales, be it neurons or people.

Chris.

Reply from chris lofting

chris lofting — Fri, 25 Apr 2008 10:57:55 -0000

Alfredo, you wrote:

“In this context, are sensations produced by excitatory processes while inhibitory processes only attenuate them, or do inhibitory processes also generate sensations? “

neurotransmitters/modulators drive the GABA/Glutamate ‘final decision’ points – e.g. serotonin drives GABA in that it stimulates production of such to be produced to then inhibit. The issues with serotonin densities will vary sensations and that includes feelings of ‘self’, i.e. depression or ‘god in the head’ syndrome!

If you analyse the self-referencing of the fight/flight dichotomy through the amygdala so the elements of that dichotomy are ‘like’ glutamate and GABA - we see interdigitations across the amygdala of ‘fightflightfightflightfightflight’. This format immediately implies self-referencing at work in that to get that level of high precision interdigitations requires a good degree of self-referencing the original dichotomy. What all of THAT indicates is that ‘feelings’ cover a dimension derived from self-referencing fight/flight, and as I have shown elsewhere we can derive the set of basic emotions from consideration of that self-referencing.

NOW apply the same dynamic to the emergence of hormones covering ‘contract/expand’ or ‘inhibit/excite’ or the expressed format in GABA/Glutamate or serotonin/dopamine(aminergics) etc

Wherever we look we will see these patterns at all scales since the primary adaptation of the neuron circa 600 million years ago was to information in the form of parts/wholes. This adaptation has been through heuristics and spanning millions of years – consciousness comes along and can reduce understanding to ‘a few thousand’ years (and these days our understanding develops exponentially and even hyperbolically!)

“The gear analogy suggests that inhibitory processes also produce conscious sensations.
Or does the balancing generate an intermediary product (e.g. dopamine release) that is the closest responsible for conscious sensation?”

Dopamine maps to management of precision (and so dominates cerebellum dynamic etc). Its development maps to times of a limibic system dominance (extending the noreadrenaline dynamics). We then move on to neuropeptides in the neocortex – FAR more efficent, compact, LOTS of choices, much higher precision dynamics and yet conserving in energy in their overall form (small strings of amin acids as compared to the chunky nature of dopamine, serotonin etc)

GIVEN the dynamics of nature, any methodology used to CONTROL and so PROTECT is then open for exploitation – ‘capitalism/socialism’ do not just operate at the cultural level! ;-) (and neuroeconomics is bring out that dynamic)

It is noteworthy that a property of mediation is DELAY Libet shows this at the neocortical level and inhibit/excite links to the soma of neurons allow for this – synchronisations and abilities to break/make instincts. Thus a possible source of development of consciousness from synaptic gap and soma managements where these positions reflect ‘gearing’ and so control. The basic neuron as such is pure stimulus-response. IT is the DELAY elements that lead to emergence of consciousness etc (IMHO ;))

Chris.

Reply from Alfredo Pereira Jr

Alfredo Pereira Jr — Fri, 25 Apr 2008 09:14:05 -0000

Dear Chris:

The operation of the whole Glutamate/GABA excitatory/inhibitory balancing can be compared to the gears of a machine, as you did.
In this context, are sensations produced by excitatory processes while inhibitory processes only attenuate them, or do inhibitory processes also generate sensations?
The gear analogy suggests that inhibitory processes also produce conscious sensations.
Or does the balancing generate an intermediary product (e.g. dopamine release) that is the closest responsible for conscious sensation?

Best

Alfredo

Reply from chris lofting

chris lofting — Fri, 25 Apr 2008 04:06:35 -0000

An essential feature of Jazz etc is being ‘free’ and so relaxing of rules of conduct etc.

If we map out the dynamics of brain rhythms we cover gamma (80Hz down) to delta (2Hz). What this brings out is the dynanics of gear usage and so analogy to one of our inventions – the engine. An engine is designed to run ‘full throttle’ (6000 revs etc) and CONTROL of such is through the use of gears – as is consciousness an agent of control (mediation) when applied to instincts/habits. Freedom is the release from rules (symmetry breaking) or the distortion of rules – this gets into the symmetric nature of law and the topological dynamics as laws are stretched/bent etc.

The GAMA/Glutamate dichotomy operating on the neurology covers the gearing issues in dealing with reality and covers the play of anti-symmetric/symmetric through the use of mediation – the asymmetric – where from such develops categories of meaning and on into language creation.

Reply from Alfredo Pereira Jr

Alfredo Pereira Jr — Wed, 12 Mar 2008 14:49:18 -0000

The interpretation of the (below) reported experiment may be essentially wrong. fMRI measurement is related to Local Field Potentials including inhibitory activity. IOW, the brain consumes arterial blood to generate inhibitory activity, i.e. excitation of inhibitory and hyperpolatization of excitatory neurons. Inhibitory activity can produce as much fMRI signals as excitatory activity.
Alfredo

Bold look at the brain on jazz finds creativity soars when inhibition takes 5

By Lauran Neergaard
ASSOCIATED PRESS

11:23 a.m. March 10, 2008

WASHINGTON – Scientists inspired by the legendary improv of Miles Davis and John Coltrane are peering inside the brains of today’s jazz musicians to learn where creativity comes from. Think dreaming.
This isn’t just a curiosity for jazz fans but a bold experiment in the neuroscience of music, a field that’s booming as researchers realize that music illuminates how the brain works. How we play and hear music provides a window into most everyday cognitive functions – from attention to emotion to memory – that in turn may help find treatments for brain disorders.

Creativity, though, has long been deemed too elusive to measure. Saxophonist-turned-hearing specialist Dr. Charles Limb thought jazz improvisation provided a perfect tool to do so – by comparing what happens in trained musicians’ brains when they play by memory and when they riff.

“It’s one thing to come up with a ditty. It’s another thing entirely to come up with a masterpiece, an hourlong idea after idea,” explains Limb, a Johns Hopkins University otolaryngologist whose ultimate goal is to help the deaf not only hear but hear music.

How do you watch a brain on jazz? Inside an MRI scanner that measures changes in oxygen use by different brain regions as they perform different tasks.

You can’t play trumpet or sax inside the giant magnet that is an MRI machine. So Limb and Dr. Allen Braun at the National Institutes of Health hired a company to make a special plastic keyboard that would fit inside the cramped MRI with no metal to bother the magnet.

Then they put six professional jazz pianists inside to measure brain activity while they played straight and when they improvised. They played, right-handed, both a simple C scale and a blues tune that Limb wrote, appropriately titled “Magnetism.” Through earphones, they listened to a prerecorded jazz quartet accompaniment, to simulate a real gig.

Getting creative uses the same brain circuitry that Braun has measured during dreaming: First, inhibition switched off. The scientists watched a brain region responsible for that self-monitoring, the dorsolateral prefrontal cortex, shut down.

Then self-expression switched on. A smaller area called the medial prefrontal cortex fired up, a key finding as Braun’s earlier research on how language forms linked that region to autobiographical storytelling. And jazz improvisation produces such individual styles that it’s often described as telling your own musical story.

More intriguing, the musicians also showed heightened sensory awareness. Regions involved with touch, hearing and sight revved up during improv even though no one touched or saw anything different, and the only new sounds were the ones they created.

That doesn’t necessarily mean this is the center of creativity. The brains of highly trained musicians might work differently than an amateur pianist’s, or a painter’s, or a writer’s, something Limb and Braun hope to test next.

“We’re all creative every day. Are our brains doing the same things?” asks Braun, who studies the relationship of language and music at NIH’s National Institute on Deafness and Other Communication Disorders.

The study’s biggest significance isn’t what it found but that it could be performed at all, opening new avenues of brain research.

“Improvisation always has a sort of magical quality associated with it. People think when you’re improvising you have some sort of inspiration that’s not measurable,” says Dr. Robert Zatorre of the Montreal Neurological Institute, a pioneer in the neuroscience of music and himself a classical organist. “They went forward where everyone else feared to tread.”

Neuroscientists call the brain plastic, meaning it has remarkable flexibility to rewire itself. Unraveling how those circuits get modified in turn helps researchers hunt treatments for brain disorders – and the same circuits that process music show strong relationships with other key brain regions. Studies show that patients learning to speak again after a stroke may improve faster if they sing rather than recite, for example. Zatorre’s team is finding parallels between tone-deafness and the reading disability dyslexia.

“What we’re doing is not necessarily trying to say, ‘Well, if we use music it will help Parkinson’s patients walk.’ It might, yes, and there is some evidence it does so,” says Zatorre, whose institute this summer hosts an international conference on music and the brain.

Instead, the quest is to “understand the rules by which the brain changes its organization. That’s what we need to know,” he adds.

Creativity comes in because its root is the spontaneity that defines everyday life. Consider conversation: Hopkins’ Limb wants to image the brains of jazz musicians “trading fours,” where one improvises four bars and the next answers back with four new bars – a musical conversation he believes comparable to the talking kind.

And no, Limb doesn’t think he’s diminishing the magic of music by finding its cerebral underpinnings.

“It’s like knowing how an airplane flies. It’s still pretty magical.”

Reply from Alfredo Pereira Jr

Alfredo Pereira Jr — Thu, 24 Jan 2008 00:37:11 -0000

Dear Mike:

Thank you again for the clarifications!
What am I interested in?
There are two kinds of approach to the relation of brain activity with consciousness: a) cness depending on higher (i.e. over baseline) spiking rates; b) cness being produced by Local Field Potentials.
In the context of a, inhibition is opposed to conscious processing. In the context of b, inhibition must contribute to cness, since it contributes to the magnitude of LFPs.
As I adopt b, I am interested in knowing how inhibitory activity could contribute to cness.

As LTD seems to use a different mechanism, I opened another forum topic to discuss the relation of LTD with consciousness (if any).

Another issue that is attracting my attention is the possible contribution of the observation of behavior of genetically altered animals for the study of cness. Some signaling molecules may contribute more than others for some kinds of conscious processing, and therefore it is predictable that knocking out these molecules cognitive impairment related to cness will occur. If a genetic modification allows inhibitory neurons to get excited, but blocks their (GABAergic) inhibitory action on excitatory (e.g. pyramidal) neurons, some behaviorally detectable alteration of cness may occur. If it is just like epilepsia, then we can conclude that GABAergic function is only limiting excitation (in this case it is functionally similar to LTD). If something more occurs, we can conclude that inhibitory activity has a constructive role for cness.

Best Regards,

Alfredo

Reply from Mike Hemberger

Mike Hemberger — Wed, 23 Jan 2008 21:49:39 -0000

Correction:
I think that simple terms like global inhibition will not enrich our mechanistic understanding on neuronal states mediating conscious states.

Reply from Mike Hemberger

Mike Hemberger — Wed, 23 Jan 2008 21:47:11 -0000

I don’t know exactly how the GABAb is constituted. As far as I know potassium but I don’t want to rule out chlorid besides.
I mean its just a different mode of inhibiton, (i) there is the GABAa mediating chlorid influx and therefore depends to be shunting (more precise, brings the membrane potential closer to the equilibrium potential for chlorid, that is – as far we know- around -70 to -75 mV). The chlorid conductance therefore “clamps” the membrane potential near the normal resting potential by counteracting incoming depolarizing potentials.
(ii) potassium flux mediated hyperpolarization (as described above).
Actually what are you intersted in alfredo, is it more (or at least for the first step) enabaling factors of consciousness or conscious states?
I think that simple terms like global inhibition will enrich our mechanistic understanding on neuronal states mediating conscious states. Inhibition certainly computes! Thats important for everything downstream…
Regards,
Mike

Reply from Alfredo Pereira Jr

Alfredo Pereira Jr — Wed, 23 Jan 2008 10:53:35 -0000

Dear Mike:

Thanks for the clarification.
Besides potassium, also chloride ions are involved (?)

Best

Alfredo

Reply from Mike Hemberger

Mike Hemberger — Wed, 23 Jan 2008 00:21:01 -0000

Dear Alfredo,
as far as I know LTD is a mechanism mostly governed by excitatory transmission, so LTD = reduction of the strength of a particular excitatory synapse.
A “global” hyperpolarization could be produced by GABAb receptors (as far as I know mostly permeable to potassium, therefore pushing the postsynaptic membrane potential near/shortly to the equilibrium potential for this particular ion ~ -100 mV).
I don’t know, however, how prominent this inhibition is in neuronal microcircuits.

Reply from Alfredo Pereira Jr

Alfredo Pereira Jr — Tue, 22 Jan 2008 12:44:31 -0000

A brief erratum concerning my last post: I am not really sure if the LTD (Long-Term Depression) process causes hyperpolarization in the same way that inhibition does. Therefore my reasoning (letter “b” in the text) should be restricted to GABAergic inhibitory action.
Alfredo

Reply from Noah Gray

Noah Gray — Fri, 18 Jan 2008 16:35:51 -0000

Basically, some neurons in flatworms, insects, arthropods, or other more simple organisms express GABA and are thus presumed to be inhibitory. The vast diversity of the mammalian inhibitory system (cell types, functions, morphology, Ca2+ handling, etc…) exhibits a complexity that has not been observed in these other creatures, suggesting that the expansiveness of the inhibitory network developed later, in an evolutionary sense. That was all I wanted to stress regarding that point.

Reply from Alfredo Pereira Jr

Alfredo Pereira Jr — Fri, 18 Jan 2008 08:50:10 -0000

Dear All:

The discussion has been very interesting and instructive, making me think about two or three factors that make inhibitory activity so complex:

a) inhibitory activity always has an excitatory phase (the excitation of inhibitory neurons);

b) there are two kinds of effects of inhibitory transmission on excitatory neurons: reducing excitation locally (post-synaptically) and producing global hyperpolarization (at least in the hippocampus – see studies on Long-Term Depression);

c) (the most intriguing issue, not found in the books, maybe my error of interpretation) physically speaking, hyperpolarization generates larger membrane electromagnetic fields (than depolarization), and therefore should correspond to stronger BOLD and MEG signals!

The role of inhibitory activity for gamma (mentioned in Mike’s last post) is another ingredient for the complexity, but maybe the relevant inhibition occurs only at the thalamus (see e.g. the Steriade model). If it is also neocortical then I would agree that relating the BOLD signal with consciousness is problematic. My tendency is to think that the connection is valid – the problem is to understand how different factors involved in the BOLD signal are more or less related to consciousness.
There is a discussion of this issue in the paper “Meta-Potentiation” by myself and Furlan (preprint published in Nature Precedings, Neuroscience section, linked in the BPCC group’s bibliography).

Best Regards,

Alfredo

Reply from Mike Hemberger

Mike Hemberger — Thu, 17 Jan 2008 22:22:04 -0000

Dear Noah,
could you please cite a paper that shows: “But, I will say that it is extremely interesting that inhibition and inhibitory neurons evolved much later than the more primitive glutamatergic transmission.”
or do you mean develop instead of evolve?

I just read the comments briefly but, logothetis also shows that the BOLD correllates best with gamma freq. and another paper shows that gamma freq is mostly carried by inhibitory neurons (Hasenstaub & McCormick in Neuron). But in general I would be very very careful with the BOLD signal and its link to consciousness, or at least the statements about consciousness extracted from the BOLD. We no almost nothing about BOLD and its not resolved enough to yet (celllevel).
In recent years another silent paradigm shift (at least for me) comes from in vivo patch clamping in awake animal, showing the sparsness of neuronal firing. the next question is: Who fires at such high freqs as reported in the last tens of years?
Another important favt about inhibition is that most of the inhibtion is shunting rather than purely inhibiting. also I’m not aware of traveling inhibitory postsynaptic potentials from dendrites to the soma, instead there seem to be differnet networks inhibiting different pyramidal compartments (e.g. soma) which presumably results in the negativity, lowering of activtiy of pyramids.

Is someone aware of studies combining single cell patch clamp recordings with bold mesurements? This would be of great interst to me,
thanks and regards,
Mike