Consciousness


The following are bits of writing from many sources such as personal correspondence, posts to on-line discussion groups, notes, and occasionally even some journaling. All of this is informal in nature, but contains some interesting and/or useful information.

Part I
[Posted to the neuroscience group on MySpace.com]
Just to clarify, I'm not saying there is a "constitution" that all neuroscience must follow, just that you pointed out in the previous post several of the basic principles that apply broadly to neurons and could reasonably be implicated in many processes such as learning and memory, sensory/motor processing, etc.
For example, "protein structures and polarity determine where the vote is sent" pretty much applies universally to all neurons. In order to pin down a particular phenomenon like we're trying to do here with consciousness, you have to find out what is going on that is uniquely correlated with that phenomenon. In other words, when rods and cones are stimulated, visual pathways are activated and vision results. If you're studying a given emotional state, then you look at which regions are active (e.g., the amygdala in fear-based responses). And so on.
Of course, how do you test for consciousness? I'm sure so much must be occurring differently in a sleeping individual vs. a waking one (e.g., vision isn't active when your eyes are closed) that it's hard to draw a comparison there. Maybe someone reading this can offer a target for this kind of study? Or, better yet, point us to existing studies so we don't have to wonder "what if...?"

Part II
[Posted to the neuroscience group on MySpace.com]
>the concept of a localized 'observer' seems too much like a reversion to the belief in a homunculus.
I haven't read the arguments either for or against this model. I realize this notion leads to an infinite regression (i.e., "Well what's inside the head of the homunculus?"), but I don't know enough about this area to replace what is obviously an outdated model with anything more sophisticated.
>and no, i haven't seen altered states.
You didn't miss anything. It has an interesting premise that I'm not going to give away in case anyone does eventually see it, but it's a dull film.
>so perhaps the 'you' (cuz i want to be philosophical too) is unique in so much as your inheritance is...coupled with neural strength due to learning from the environment
>so the stronger the connection...the faster the signal...the more likely that that network is to send its signal of excitation or inhibition and influence the subsequent place than any other connection. the brain is kind of like a democracy...with each cell casting a vote:
>the stimulus determines which regions vote, genes dictate how they vote, conditioning and structure (enzymes, catalysts, etc.) determine how fast they vote, and protein structures and polarity determine where the vote is sent. the fastest vote wins...and the most of the same vote to get there first determines action or thought
I think we accept all of the above as basic tenets of the design of most neuro-systems. The mystery lies in how these things (and/or others) give rise to the phenomenon of consciousness (or whatever it is we're talking about).
No, I don't have a solution either or I'd be in Stockholm picking up my medal.

Part III: experimental design
[Posted to the neuroscience group on MySpace.com]
That's a good one, but not for neuroscience.
I don't mean to belittle your submission in and of itself, but we have to have something measurable if we're going to subject consciousness to hypothesis testing.
I'm sure there are a lot of good semantic definitions that are cute, clever, entertaining, etc., but unless we can actually "isolate" consciousness under controlled conditions, it's kind of hard to say that we're all talking about the same thing. That isn't to say there's no subjective elements at play in research, but we have to nail something down before we can all be on the same page.
For example, in testing emotions, you can't get, say, a rat to fill out a questionnaire about how frightened (s)he was upon being startled. Instead, if you're looking at fear, then you put the rat in a "startle chamber." You scare the rat with an overwhelming stimulus (e.g., a loud noise) and the rat jumps. The magnitude of the jump is registered through a piezo-electric sensor that is activated by movement and the resulting signal is quantified. The values recorded then reflect the intensity of the emotion of fear (or at least how startled the rat was).
That may be indirect, but you can at least make comparisons across the results. That's what makes it science. (And sorry if that startled any animal lovers.)

Part IV
[Posted to the neuroscience group on MySpace.com]
A fMRI or PET scan approach like you're suggesting assumes that consciousness has been localized and we can monitor activity in that region. While many regions influence conscious awareness (e.g., our visual cortex, just to pick a really obvious one), they don't seem to be the "seat" of consciousness.
As far as I know, there are no knock-out mutants for consciousness. (Although, yes, being knocked out would render you unconscious, but that's a different story.) Unlike the aforementioned H.M., I haven't heard of any individuals who lack a specific region through surgery, injury, or altered development that resulted in them being impaired in their consciousness. Then again, we still haven't pinned it down to something we can compare

Part V
[Posted to the neuroscience group on MySpace.com]
That parallels with how memory is viewed. While specific memories (or facets of memories) are stored in specific regions (e.g., visual memories in the visual system, kinesthetic in the cerebellum, etc.), the process seems to be a generalized biochemical phenomenon between a couple cells at a time.
However, the odd thing is that, whereas you have a collection of memories, consciousness seems to be something central, like there's only one of it. And it's you. You can lose specific memories, but your consciousness (i.e., the core awareness of self) seems to always be there from moment to waking moment. The mystery is how a distributed phenomenon can have a singular outcome.

Part VI
[Posted to the neuroscience group on MySpace.com]
From Ian:
>so it's the integrative factor between observation and memory, a lens or perspective used in the interpretation.
I think this discussion is vacillating between two facets of "consciousness." They overlap, but I think they're distinct enough from one another that we ought to identify which we're talking about as we proceed.
The first of these is the idea that consciousness is this central awareness of self (I'm writing off-line; better summaries of this were put forward in this thread). In other words, there's a little (wo)man in your head who monitors everything and is conscious of the fact that (s)he exists and is "you" in a very definite sense.
What you mentioned above touches (as I read it) more on the second definition: That consciousness is aware not simply of self but of sensory input. Hence we have "altered states of consciousness" achieved through sensory deprivation or modification of senses through pharmacological manipulation. (Anyone besides me and Lost Psycho ever see "Altered States" starring William Hurt? It has examples of both approaches.)
Naturally, consciousness is informed in either case by sensory input (among other things), but I've been thinking in terms of the first definition where it's just you knowing you exist. (And maybe I ought to put "you" in quotes again just to be all philosophical about it.)
>How about the influence and universality of biochemistry?
I'm not sure what you're getting at here. There are a lot of ubiquitous reactions. However, I don't know that I would implicate, say, the Krebs cycle directly in consciousness. (Yes, I know if you universally stopped that reaction, you wouldn't say consciousness for long, but you see where I'm going). It's more about the specific arrangement of neurons (along with which kind are present and their respective properties). That is largely under the control of gene expression, although gene expression is also under the influence of experience. People (Republicans, especially) seem to forget that a lot of the time.

Part VII
[Posted to the neuroscience forum on MySpace]
>I guess i don't understand the question that isn't being answered.
We still don't have an operational definition of consciousness. Without that, no one has enough of a handle on the concept of consciousness that they can address any questions about it.
For example, in studies of learning and memory, Eric Kandel used habituation (i.e., getting use to a stimulus) as a measure of learning. In this case it was withdrawl of a "fin" by a sea slug. He showed that the behavior of the animal changed according to its experience. From there he did work on the cellular level and won the Nobel Prize in 2000 for his work in unraveling the biochemistry behind this change.
Before you can go chasing after something as intangible and ethereal as consciousness, you have to nail it down to something you can measure in the lab. The discussion in this thread has already shown we all have different ideas about specifically what consciousness is and how to approach it. If a consensus cannot be reached on just this fundamental level, then no matter what you may find somewhere down the line in your research, you will have trouble convincing anyone that you actually discovered anything about consciousness. Everyone may agree you found something, but not that you are actually working with consciousness.
This has been an issue with Kandel as well. Many people think his findings with regard to habituation are interesting, but there is some skepticism that this is really getting at learning and memory. In other words, maybe he is looking at a parallel phenomenon or only one type of learning when, in fact, many are involved, etc.
I don't mean to bring you down or to discourage your or anyone else's thinking in this area, but you have to establish this benchmark up front before you can even begin generate testable hypotheses.

Part VIII
>It boils down to a plato-like dualism.
I think you're thinking of the Cartesian model of mind/body (after Decartes), but, yeah. And it would be nice if everyone got past this and recognized that not just mental illness, but *all* mental processes (so far as we have been able to determine) have a physical basis. So long as we are biological entities, we will have the potential to be affected by physical influences.
>I feel the main problem is a kind of chicken-and-the-egg situation where we can't say for sure which came first
Speaking of philosophy, the problem with this view is that it is linear and modernist when a post-modern view would be more appropriate. The interaction between genes and behavior is a dynamic, on-going process, not a singular trajectory. Further, the interaction is not unidirectional either. There is constant recursion that might read as: "world affects us, gene expression is changed, behavior is changed, world affects us differently, gene expression is changed accordingly, behavior is again affected," and so on. Cause and effect are still present, but the concepts of independent and dependent variables get blurry.
I gave one particularly dramatic example in an earlier thread that used the Grand Canyon Tiger Salamander, and there are many others I could cite a little closer to home. Some of these are similarly dramatic like PTSD, but even basic everyday learning fits the recursive model above.
In the case of depression, there's an example of this recursion in the symptoms themselves. Physical activity and mental processes are connected bi-directionally. If you're depressed, you tend to be physically inactive. If you're inactive, your depression is likely to intensify. Of course, getting a depressed person to engage in physical activity is difficult by virtue of their mental state, but that's an example of the recursion process I want to emphasize. The pathology emerges from behavior and biology feeding off of one another.




Copyright Alexplorer.

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