[Fis] Fwd: Further comments

[jose luis perez velazquez]

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From: jose luis perez velazquez <jlpvjlpv at gmail.com>
Date: Wed, Jan 9, 2019 at 12:51 PM
Subject: Further comments
To: <fis-request at listas.unizar.es>


      Colleagues, thank you all for your comments to our New Year's digital
seminar. I will try to answer some things in those comments  received so
far in a more or less compact manner.

      *Francesco R*. points out different notions of consciousness, and
also of entropy. Let us clarify some things that, perhaps because of the
word limitations, were not made apparent in the “talk” and of course more
details can be found in the two PRE papers listed in the references.
Nonetheless, let me say for now that we deal with *conscious awareness*, we
prefer not to delve into the diverse connotations of consciousness
(Edelman’s primary consciousness, higher-order etc.), rather our study
deals in fact more with *optimality of sensory awareness* than with
consciousness itself (even though these two are absolutely related, of
course). Let me explain why because that was something we could not
describe in the text due to the space limit.



     Briefly, as can be seen in our PRE 2016 paper, the entropy associated
with subjects closing their eyes is lower than that calculated with eyes
open. Obviously, one is equally conscious with eyes open or closed (unless
one is sleeping!). Thus, what does this mean? In animals like us that
depend almost totally in visual input, stopping visual stimuli to the brain
causes remarkable changes in brain dynamics. To wit, the appearance of very
rhythmic oscillation, the alpha rhythm, in parieto-occipital cortex (but it
can be recorded as well in frontal and temporal areas). Some studies have
found that brain complexity is lower and its structure more organised with
eyes closed (I don’t exactly remember but I think they used graph theory or
similar), not too surprising after we see the very periodic and beautiful
alpha; hence, not surprising either that this “more organised brain” is
manifested in our study showing lower entropy. For these reasons, we tend
to think that our entropy reflects more *optimality of sensory
manipulations* rather than “pure” consciousness (for visual animals like
us, being blind is not optimal at all!).



     And this brings us to Francesco’s comment on the diverse entropies
(which I will call from now on S for short… my fingers are getting tired of
typing). There are indeed different notions of S and this is why it is
important to specify what S is being computed. In our case it is the S
associated with the *number of configurations of connected
signals/networks.* *Pedro C.M*., in two of his points, refers to entropy,
for instance: “ if the inner processes ring some alarm, that entropy would
escalate enormously”. This in fact cannot occur in our case, because the S
has a maximum value for certain number of configurations of connections,
namely, when the number of connected signals are the same as the not
connected. This is why the S graphs in the papers (and in my cartoon in the
talk) are inverted Us, a Gaussian basically – the maximum S is at the top
of the curve, it cannot increase any further. Many of the S values we see
in awake-eyes open are close to this top, hence almost maximal.  It is
important to emphasise again that we are evaluating the number of
configurations of connections, the fact we go one step further and obtain
an S adds very little in terms of concept but makes the wording and data
presentation easier. That is, in awake-eyes open we have near maximal
number of possible configurations (our microstates), and the macrostate is
represented by all those configurations. For those into chemistry, this is
akin to chemical equilibrium: equilibrium is found at the top of the
Gaussian where the quantity of the two molecules of a chemical reaction
(for the sake of simplicity let’s assume it is a reaction involving 2
molecules) is the same, and far from equilibrium we have lots of one
molecule and little of the other. Sorry for this digression into chemistry,
but I am a biochemist after all.



        So this is our S, but if we were to consider the S applied to other
aspects, say, ions/molecules, it would be different. Just extract the brain
of a mouse and homogeneize it (a common biochemical technique to make
neuronal milk shake). The S of molecules has increased vastly, complete
disorder of ions and molecules. But this is not the S we are talking about
here. That molecular mess cannot process any information/sensory input
because there is no organization of cell networks, connections and all
that.  Can our S capture brain dynamics, as *Pedro* asks? To some extent,
but only in its global character, this is then reason for the second PRE
paper, “Consciousness as a *global property* of brain dynamic activity”, where
we used LZC which allowed us to capture the “microscopic” dynamics, the
fluctuations in the configurations of connections that our S cannot
capture. By the way, Pedro, when you say “All the brain areas relatively
silent in the left side of your figure, when transiently connected with
some portion of the central cluster of the conscious space”  I am not sure
you understood the figure, the x-axis does not represent “silence”, or
activity, in brain areas, it is number of synchronous channels:  in the
left the number of synchronised networks is lower, but those nets may be
very active, just not synchronised. Higher activity does not always lead to
more synchrony, to wit, right at the start of epileptic seizures, when the
cellular activity begins to grow, there is normally a decrease in synchrony
(which then increases during the ictal event).



*      Loet L.,* *Joseph B., *and *Francesco *have related points
mentioning Prigiogine’s order through fluctuations and emergence. My
opinion is that S is a concept humans created to characterise/understand
phenomena, but I would not claim it is the cause of processes (like H.
Haken thought as well, in his “Information and self-organization” book). It
is for this reason we normally use the terms “S associated with…” in our
papers. It is hard, in open, complex systems, to talk about cause and
effect. As *Joseph B*. mentions, the emergent entity being actualized is
not totally separate from states from which it emerged. Remember Haken’s
enslaving principle.  The “control mechanisms” (Loet’s words) that may
exist operating in neural feedback loops are hard to disentangle, because,
due to the enslaving, one microscopic aspect may become a macroscopic
“force” at some level. *Alexander F*. mentions their theory about the
nested hierarchy of brain processes and talks about causal relations. But
as for our study,  we don’t know. All we can say is that awareness is
associated with larger number of possible configurations of connections
among brain areas that may be needed for the integration and segregation of
sensory-motor activities. We are now, as an extension of our work, trying
to come up with an evolution law, something that will allow us to make some
predictions about what can be found in certain brain states. This evolution
equation may be related to the probability of connections, but we are not
sure yet… this is something for another talk.

       Let me mention too that fluctuations are fundamental for pattern
formation, and in the nervous system we talk about fluctuations in
synchrony that, perhaps via dynamical bifurcations (the existence of
bifurcations in brain activity, at least in epilepsy, has been obtained *in
vivo: ‘*Dynamical regimes underlying epileptiform events: role of
instabilities and bifurcations in brain activity’  Perez Velazquez et
al.,  *Physica
D*, 186, 205-220, 2003), create patterns of organised neuronal activity. It
is this organised activity pattern that is the fundamental for a proper,
healthy brain information processing. In seizures you find lot of synchrony
with not enough variability in the configurations of connections, hence not
good for sensorimotor processing, thus loss of awareness is common during
seizures. There is an extensive literature suggesting that variability in
brain activity is associated with good health -- not only in
neurophysiology, but also in cardiac activity, hormonal concentrations etc…
Variability makes you healthy!).



     Sorry we missed, in our papers, to mention some parallels of our
results with* Alexander F’s *Operational Architectonics*, *above all that
phenomenal consciousness refers to a higher level of organization in the
brain. We will take note of this for future publications.



   And finally, let me mention that I tend to agree with Pierre Gloor in
his view of consciousness that he expounded in ‘Consciousness as a
neurological concept in epileptology: a* c*ritical review' (*Epilepsia *27
(Suppl. 2): S14-S26, 1986): “Consciousness cannot therefore be external to
itself; it cannot be an “object, out there”; it thus cannot be observed. If
I may be allowed to use the metaphor of describing consciousness as the
*only* window through which we can look at the world, then it follows that
when looking through this window we cannot see the window itself, even
though it, too, is part of the world. Consciousness thus conceived is not
an objectively verifiable datum; it therefore cannot be defined, and its
very nature is not accessible to any form of objective analysis”.

 Like Gloor, I do not want to search for strict definitions of
consciousness, rather for properties of it, which can be investigated, e.g.
memory, self-awareness, motor actions etc.  To me, consciousness, like
life, can be best defined by enumerating properties rather than by a strict
sentence.



   This is all for now. My colleague Ramon, I am sure, will have more
things to add and comment.



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