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Evidence for Globalized Consciousness

  1. Jun 13, 2012 #1

    Pythagorean

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    new article (note, the above quote is from the news article, so subject to journalist interpretations):

    http://neurosciencenews.com/conscious-perception-global-neural-networks-prefrontal-cortex/

    peer reviewed article:

    http://www.cell.com/neuron/abstract/S0896-6273(12)00380-7
     
  2. jcsd
  3. Jun 18, 2012 #2
  4. Jun 18, 2012 #3
    This is saying that visual consciousness is located in the temporal lobes and also in the lateral prefrontal cortex. I am not seeing how this supports the view it's global, as the article asserts it does. Some piece of that reasoning is missing as far as I can see.
     
  5. Jun 18, 2012 #4

    Pythagorean

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    the two camps have been localized vs. global. Global really just means not localized. I.e. distributed... that there's no "seat of consciousness"
     
  6. Jun 18, 2012 #5
    Where do the localizers localize it to, the thalamus?
     
  7. Jun 19, 2012 #6

    Pythagorean

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    Last edited by a moderator: May 6, 2017
  8. Jun 19, 2012 #7
    A guy named Hypnagogue who used to post here brought the claustrum to me attention once (he'd probably been reading about Crick) but this is the first I've heard of the precuneus being a suspect. It seems that two separate things are being discussed, though. In your article the issue is consciousness of the visual field. The precuneus is asserted to have bearing on sense of self. These could both be true and non-contradictory.
     
    Last edited by a moderator: May 6, 2017
  9. Jun 19, 2012 #8
    I also think we need to remember that localising the "seat of consciousness" is a bit of a copout. We have localised it to the brain so far but we still have no clue how it works. Localising it to an area of the brain would be much the same. It would certainly be interesting and would direct further research, but it wouldn't be much of an answer to the real mystery of consciousness.
     
  10. Jun 19, 2012 #9
    It would only be a copout if you stopped there and thought you'd explained consciousness. If it is localized, though, you won't be able to explain anything until you find the location and analyze what's happening there.
     
  11. Jun 19, 2012 #10

    Pythagorean

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    You'd have to have accepted distributed consciousness already to see consciousness as something that can be divided functionally like that :)
     
  12. Jun 19, 2012 #11
    I think that brings up a nuance in the distributed/localised debate. Different aspects could be localised in different brain areas, but there is a stronger sense of distribution in which no aspect of consciousness might be localised any single brain area. This would be the case if visual consciousness was itself distributed throughout the brain, and so was the sense of self etc. I would probably favour the stronger form of distributed consciousness. Bear in mind also that our overall consciousness seems take take place after the integration of the various senses and the sense of self etc.
     
  13. Jun 19, 2012 #12
    You bastard! Saw right through me! :)
     
  14. Jun 19, 2012 #13
    I don't know if there are any "schools of thought" that assert this, but my own notion is that consciousness is a collection of tiny parts, pixels as it were. A firing neuron may be the equivalent of a pixel. Groups of neurons that fire in response to the same things, say stimulation by light wavelength (color perception), constitute a kind and level of consciousness unto themselves. Were there some primitive life form that only had this kind of neuron (and accompanying receptors) we could call it conscious, but it would, of course, be a very limited consciousness compared to ours.

    By this reasoning, if you cover an eye with your hand you are subtracting some consciousness. Close both eyes, you subtract more. Go to sleep and you subtract a very large chunk.

    Someone could easily consider this simplistic, I'm aware. It ignores the whole issue of "intelligence" among other things.
     
  15. Jun 19, 2012 #14
    I would tend to side with the predictive models of perception (and by extension consciousness). These theories model perception as the result of an internal, heirarchical, top down set of predictions which attempt to "explain away" the incoming sense data. In this way, a group of neurons don't fire in response stimulation by a wavelength of light in a bottum up constructive manner. In fact, neural signals should represent the error between prediction and incoming data according to these models.

    To me this seems to provide a more integrated and less atomistic view of consciousness. I also think it is more in line with the fact that we are conscious at all. A passive, bottom up filter between sensory input and motor output would intuitively seem less conscious than a system which generates an internal model of the external world and attempts to predict the incoming stream of sense data.
     
  16. Jun 19, 2012 #15

    apeiron

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    Yes, this is simplistic. :smile:

    It is not a case of local vs global but about how the two things work together. So "a state of conscious awareness" is both a highly particular state (the brain is intent on some single focal view) and also a highly general state (at the same time, it is actively pushing everything else it "knows" into the background).

    So where it comes to neural firings, the dog that didn't bark, my dear Watson, is also part of the state.

    All neurons are firing off all the time. Unless they are dead. But firing rates get suppressed, become unsynchronised, etc, if the brain wants to push "what they are saying" into the background.

    This is why some theories of consciousness (like one of Crick's multiple attempts to locate a seat of awareness) stress the thalamus, a crucial bottleneck in orchestrating what cortical activity is currently being enhanced, and what suppressed.

    But the prefrontal is also very active in this same orchestration (reaching down to the thalamus to control it) so can also seem to be a seat of consciousness (of the spotlight of attention).

    So a better mental image is to think of the brain as a buzzing confusion of neural rustling - the kind of day-dreamy unfocused awareness you get when idling. Which can then be kicked into states of high-contrast representation by turning up some neurons/circuits, and suppressing the contributions of others.

    In this way, consciousness is the result of local~global differentiation and integration. The whole of the brain is always involved. But locally, some activity is ramped up, other activity suppressed. And the dogs that don't bark count along with the dogs that do so far as the final experience goes.

    This explains stuff like priming or the fact you only notice the hum of the fridge when it switches off. Your brain was representing the hum, but it was also suppressed to the level when it was not part of your focal spotlight. But the sudden absence of a now expected part of your mental background is the dog that stopped barking. And so the brain shifts its focus to find out what happened exactly.
     
  17. Jun 19, 2012 #16
    This all makes sense, and it describes what my mind always seems to be up to, but it seems you are equating attention with consciousness. I would class them as two separate considerations.
     
  18. Jun 19, 2012 #17

    apeiron

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    No, it would be the sucessfully attended plus the successfully ignored that adds up to some particular state of consciousness in this view. If there is a spotlight of attention, then by the same token there is the penumbra of all that is not being attended - or rather actively suppressed.

    So attention leads to what is reportable. And that can seem like all that matters. But you may know from fine arts 101 that they start you off by focusing on negative space so that you "really see things". You can't have the light without the shade, the object without the context. So you have to step back and learn to clearly see all the things you had learnt to ignore.
     
  19. Jun 20, 2012 #18
    This all makes sense and is plausible, but it doesn't particularly explain why we would become conscious of the difference between prediction and data stream, or why that difference would become conscious of itself. How is that difference manifested in neuronal activity? Suppose you can tell me exactly: the predicting neurons do this and the data neurons do that, and there's this difference between the two. How does that difference become a conscious experience while the other activity remains unconscious?
     
  20. Jun 20, 2012 #19

    apeiron

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    There aren't these two types of neurons. Instead the brain generates a predictive state in the neurons - a mental image of what is likely to happen - and then what happens gets matched against the prediction.

    This happens all the way down to the "input" level as shown by the way retinal ganglion cells fire off ahead of an expected event.

     
    Last edited by a moderator: May 6, 2017
  21. Jun 20, 2012 #20
    OK, it's the same neurons experiencing both the prediction and the actual data. Same question though: how is the difference between the two transformed into "consciousness"?

    I saw Ramachandran on TV many years back pointing this out: we are only conscious of differences. That stuck with me.

    But this leads to the same question I asked madness. How does difference become consciousness? Why doesn't a table become conscious when I press on it as I do? The table experiences just as much difference in pressure. I have neurons firing and the table doesn't. There has to be something unique about the firing of a neuron that it leads to me becoming conscious of the table while the table remains unconscious of me. That's my reasoning.

    I'm guess I'm betraying a prejudice for EM activity as the root of consciousness because consciousness seems to demand something dynamic and "electrical".
     
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