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Correlates of Consciousness

  1. Dec 15, 2003 #1
    Are there some particular types of neurons, distributed over the visual neocortex, whose firing directly symbolizes the content of visual awareness? One very simplistic hypothesis is that the activities in the upper layers of the cortex are largely unconscious ones, whereas the activities in the lower layers (layers 5 and 6) mostly correlate with consciousness. I have wondered whether the pyramidal neurons in layer 5 of the neocortex, especially the larger ones, might play this latter role.

    These are the only cortical neurons that project right out of the cortical system (that is, not to the neocortex, the thalamus or the claustrum). If visual awareness represents the results of neural computations in the cortex, one might expect that what the cortex sends elsewhere would symbolize those results. Moreover, the neurons in layer 5 show a rather unusual propensity to fire in bursts. The idea that layer 5 neurons may directly symbolize visual awareness is attractive, but it still is too early to tell whether there is anything in it.

    I believe that once we have mastered the secret of this simple form of awareness, we may be close to understanding a central mystery of human life: how the physical events occurring in our brains while we think and act in the world relate to our subjective sensations—that is, how the brain relates to the mind.

    What do you PF hypothes-izers think of this?
  2. jcsd
  3. Dec 16, 2003 #2
    I think you are right about the possible ramifications of this kind of discovery.

    Personally, I really like William H. Calvin's hypothesis on this (as put forth in The Cerebral Code: Thinking a thought in the Mosaics of the mind), which is a selectionist idea (basically, the idea that Darwinian processes (not just natural selection, but all of the Darwinian evolutionary processes) in the neocortex are what produce conscious experience), but with an extra facet: He thinks he's identified the most fundamental structure of perception, the "stupid demons" of Dennett's theory, the so-called "Hebbian" (after Donald Hebb) cell-asemblies. He believes that they are hexagonal patterns of synchronously firing pyrimidal interneurons, each from its own triangular array. IOW, the synchronously-firing neurons form triangular arrays of "flashing" self-stimulation (that's leaving aside the spatiotemporal "new" firings, in which case self-stimulation would obviously not be necessary), and one member from each array fires along with five other neurons (each a member of another array) thus producing hexagonal shape, with a "hot-spot" in the center.

    This is an over-view, and I probably couldn't explain it as well as he can, so you should probably read the book. Be warned, however: if anything that I said above seemed "beyond" what you're used to (more technical than you can "keep up with") use the glossary constantly (and keep a dictionary handy too...or, at least, I do ) .
  4. Dec 18, 2003 #3
    Has anyone heard of Calvin's hexagon theory before?
  5. Dec 27, 2003 #4
    Its already been established that Internal Monologue (which arises from the Corpus Callosum) plays a major part in self-awareness.

    There are no "consciousness neurons", but all the parts of your brain work together to make humans the conscious devils that they are. (Devils? )
  6. Jan 2, 2004 #5
    Re: Re: Correlates of Consciousness

    I agree with most of this...but, please be more specific as to how the Corpus Callosum produces Internal Monologue.
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