Freeman, Walter J. (2007) elaborates the topic in his paper: Indirect biological measures of consciousness from field studies of brains as dynamical systems

I personally doubt that criticality will help us pin down the dynamic basis of conscious perception. I go with Christof Koch and Horace Barlow in thinking that we need to focus  more on the significance of the firing of individual neurons. There may well be avalanches but that does not mean that each signal is not conveying some specific information of its own - and we want to know what that is and why it has signalled. Ideas like 'ignition' or 'phase transition' are evocative but I doubt that they lead to useful predictions. What they may illustrate is that perception is a competitive business in which many many bits of data vie for salience. But we know that must be so.

Just remind that Tononi was looking for a system with maximal Integration and information, critical state has them both, actually, the best solution for Information integration might be a critical state.

I do agree that each part shares its own information, but our perception consists of many many parts, as you said, and they should share it together while the system enters a "state".

maybe that state is an avalanche

Dear Abolfazl,

I have to say that I do not understand these claims. Tononi talks of integration in a new sense that he has devised, the relevance of which to consciousness I find hard to understand. He talks of information of a sort that he says is not Shannon information but a new sort called intrinsic information that he has devised. Again, I am unclear what it tells us about consciousness. Moreover, my understanding is that the special behaviour of a critical state has a lot to do with dynamic dispositions being correlated and correlation is the opposite of information - it is redundancy.

I am sceptical about the idea of a brain being a system in a state. Tononi uses models based on digital electronic systems (automata) that do sit in 'states' during time frames but nerves do not have this feature. Their dynamics are different - and Tononi rightly points out in IIT 3.0 that it cannot be applied to brains (somewhat surprisingly for a theory devised to understand brains). Brains do not enter states. We are conscious all day long. The avalanche behaviour looks to be to do with switching salience in pre-conscious pathways, like scene changing in a play, which is very interesting but nothing to do with the richness of the information in consciousness I think.

To my mind one should always resist the temptation to treat something as 'a system'. Truly understanding complex dynamics depends on understanding the component elements and their interrelations regardless of any concept of a system. Looking for a system oversimplifies and leads to non-local explanations that in the end have no explanatory value. Causal dynamics in science must always be local down to the level of individual modes of excitation. For crystals and paramagnetism mode domains can be very large but I have not yet seen a reason to doubt that brains obey locality down to the neuron level, as in the neuron doctrine.

Recent work on Astrocytes suggests that they contribute to gamma wave coherence which might be part of the story in criticality. However whether this takes us any further in the approach to consciousness depends on whether or not you think that consciousness requires great coherence to exist. Instead, I think that it is involved in the conversion between implicit priming memory and implicit delay type memory, which is a previous stage to consciousness, and contributes to it, but isn't the cause.

I think to blame criticality for consciousness is to make consciousness arcane and only specialists need to apply to figure out how it works. Instead evidence seems to support a more prosaic description such as a reflexive re-entry at a certain place in the brain.

Domassio's work on the brain stem seems to suggest an early link between consciousness and Brain development that then has been incrementally added to by evolution a number of times, which is why I support the triune model of consciousness.

Based loosely on Macleans triune model of the brain, it suggests that there are three evolutionary epoches during which innovations to the brain resulted in changes to the nature of consciousness. the Reptile brain, the old mammal brain, and the primate brain each have offered their own innovations to the Domasio core consciousness.

The Reptile consciousness is a purely reactive consciousness, the old mammalian conciousness has emotional consciousness, and the primate consciousness allows out of band thinking to add to consciousness.

This suggests that the consciousness falls in the brain stem with reflexive re-entry by  at least three different classes of reactions.

Part of the problem we have with attempting to study this, is that imaging tends to be much more difficult the deeper into the brain we go. You can't get much deeper than the brainstem.

Dear Jonathan

I think the critical state can help information processing by maximizing repertoire of the system. ( correlation length mutual information diverges at critical point, In statistical mechanics, the correlation function is a measure of the order in a system). so a critical state maximizes the capability of the brain to process different information and enter different states.

I agree that if sb looses the track of local interaction and single unit dynamics will loose the entire phenomenon. but criticality appreciates the local dynamics and that's threshold dynamics in the neurons. ie. they fire when their inputs push them to a threshold then they collapse (fire) and then the next one does the same and.... an avalanche happens.

Criticality is in its infancy. although I personally think there might be more than criticality in the brain.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3429078/

Dear Graeme

I personally doubt the notion that brain stem accounts for the consciousness. brain stem seems to be a power plant for the cortex. not imaging but lesion studies showed the role of brain stem in consciousness. I think power plant scenario goes well with evidence.

sleep studies, comatose patients, imaging studies showing the cortical activity etc.

I was wondering if you can elucidate the Idea a little bit more.

Thank you Abolfazl, I will attempt to though I despair of the details. It seems that Maclean got the Reptile part of the brain wrong. Mammals branched off before reptiles in the Cade analysis.

In any case, the idea is that evolution has brought a number of versions of the brain into existence over time. While the exact nature of the evolution of the brain is still controversial the idea is that Human consciousness is the result of a process of evolution that resulted in the development of the modern brain.

The evolution of the brain brings with it, a more elaborated brain, with greater capabilities by picking up on specific epoches in the process we can see a sort of progression from basic core consciousness to a more fully elaborated human consciousness.

While I am not sure of the exact epoches to use, and we can be sure that within those epoches some species may tend to reduce their elaborations rather than increase them, The idea is that the process of elaboration took time, and was done in stages.

We only have the end results to work from, which means that we have lost some of the information in between losing some of the enabling steps due to die offs and extinctions. As well, evolutionary evidence does not stay still, some portion of the evidence is always changing, so even the less elaborated brains that exist today are probably not the same as the ones that existed in prehistoric times.

But beyond all those caveats, we can see a sort of progression of elaborations that might explain the eventual development of the human brain.

I am currently studying an introductory work on comparative neuro-anatomy of Vertebrates under the mentorship of John LaMuth. So hopefully my theory of consciousness will develop under his tutelage.

In any case, the idea of brain development in stages brings with it, the idea of a progression of stages that results eventually in the human brain. This should be seen as different from scala Naturalae in that it doesn't assume that the human brain is the pinnacle of evolution, just the most elaborated of the brains under study.

Evolution moves in both the direction of elaboration and simplification, depending on the ecological niche of the species, so it is possible that a simplified species is actually better evolved for its niche than humans are for theirs.

Whether or not we look to cade analysis, consciousness probably developed in stages along with the brain. My research is attempting to find a model that will explain the complexity of human consciousness in the best way possible while it assures that the complexity grows according to recognizeable steps.

Context level shifts can describe simple rules and plans via complex contextual interactions.

I agree with Abolfazl Alipour