How the Brain Does Consciousness: Biological Research Perspectives

[Piggy]

I don't think so.
The original experiments were done by Sperry. This guy knows less than my average intro psych student. Why should I have to pay any attention to his BS?

I left my book again, but I'm pretty sure he was referring to his own split brain studies there. This guy is Michael Gazzaniga, btw. (And you've got some damn smart students!)

 

[Piggy]

Anything beyond direct reference to peer reviewed research is "philosophical" to you. That's your problem. If you want to ever actually "understand" things you have to make some abstractions and connections in your own head, and be willing to call it "inference" instead of "philosophy."

This thread is not the whole world.

There are some articles I've read recently on consciousness that I think are very interesting, for instance, but they're not sufficiently research-based for me to post them here.

Did you want to make a point about the relationship between the visual system and consciousness?

If so, you could just make it, you know, instead of starting what feels a lot like a Platonic dialog.

But yeah, when we get away from discussing brain research, and start into an exchange about abstractions -- however interesting they may be (seriously, no sarcasm there) -- then we're getting into a philosophical approach, which I'd rather not get into here.

 

[Piggy]

Doesn't seem like the "discussion" anyone else is after, perhaps that is why the thread is so slow.

It very well may not be a popular subject. That's ok. I don't care how slow the thread goes, as long as I get to see stuff like yy2bggggs posted from time to time.

And I don't mind talking about any issue related to the research, as long as it is, you know.

Speculating about areas that the research hasn't yet clarified, tho, is just that, speculation, which can be discussed endlessly while going nowhere, so starting a thread explicitly about brain research was the simplest way to control that.

I mean, look, if I try to brush you off and I'm wrong, I've probably just lost the train of the discussion -- just remind me of what studies we're talking about.

 

[Piggy]

Ah, see, now we are having a discussion.

Also, now you have a conundrum, because the above conclusion doesn't play well with your desire to limit the discussion to "actual research" and not delve into the "assumptions and suppositions" one can make using such research as evidence. A direct conclusion from the above might be:

1) The brain behavior required for consciousness doesn't depend on visual input (it might still use the visual system somehow), which means any references you make to studies that use visual input need to be framed in that context -- something you have not done because you are so hesitant to draw any hard conclusions. Why does consciously monitoring for a stimulus allow us to perceive it so much better? Well, if such behavior doesn't directly depend on the kind of stimulus in question, there are a number of inferences one can make about how the mechanics behind it might be organized. And there is no reason to doubt the validity of such inferences -- neuroscientists aren't necessarily smarter than you or I, piggy, they just chose a different line of work.

For instance, your refusal to answer the simple question of what your own conclusions are regarding the nature of human consciousness is bewildering to me. Are you afraid to be wrong? Thats the point of a forum, making posts and learning from your mistakes.

2) The brain behavior required for consciousness does depend on visual input, in a person who can see, and the brain behavior required for consciousness doesn't depend on visual input in a person who is blind. In which case, the only way to make sense of a "generic" human consciousness is to abstract away from the direct topography of seeing and blind people and look at the kind of information processing pathways their brains have in common -- somethign you seem categorically unwilling to do, because it involves computer science and modeling and all sorts of ideas that can't be gotten with a scalpel/microscope/ MRI machine alone.

3) The brain behavior required for consciousness depends on visual input in both blind and seeing people, meaning blind people are not conscious. Obviously this isn't a serious contender.

Let's see if I can keep this from getting philosophical...

The brain behavior required for consciousness doesn't depend on visual input (it might still use the visual system somehow), which means any references you make to studies that use visual input need to be framed in that context

The most prominent studies in that area depend on that context, in fact. For instance, the cited studies on recognition of emotion in human faces and on brain behavior during conscious and subliminal perception of images.

Why does consciously monitoring for a stimulus allow us to perceive it so much better? Well, if such behavior doesn't directly depend on the kind of stimulus in question, there are a number of inferences one can make about how the mechanics behind it might be organized.

Sometimes it will depend on the kind of stimulus, since our brains are built to quickly recognize certain things, such as snakes, large predators, human faces, and biological motion.

As for why volitional attention and prediction increase the speed and accuracy of detection, I'd go back to the study of predictive imagery. If you're primed to look for something you're familiar with, you've got an overlaid imagined pattern that you can include in your predictions.

And sure, there are inferences to be drawn from brain studies in this area, and there's no problem with drawing them.

Now, I will say, tho, that inferences can get dicey pretty quickly. For instance, I don't know of any way to be sure that consciousness is actually involved in the process of being put on notice to be on the lookout for something, or is simply aware of it.

For instance, your refusal to answer the simple question of what your own conclusions are regarding the nature of human consciousness is bewildering to me.

I think the question was about what I "believe" about consciousness.

I don't mind discussing conclusions drawn from brain studies, my conclusions or anyone else's.

I've mentioned some in earlier posts.

But I'm not about to simply expound on a general theory of consciousness. (Not in this thread, anyway. )

The brain behavior required for consciousness does depend on visual input, in a person who can see, and the brain behavior required for consciousness doesn't depend on visual input in a person who is blind. In which case, the only way to make sense of a "generic" human consciousness is to abstract away from the direct topography of seeing and blind people and look at the kind of information processing pathways their brains have in common -- somethign you seem categorically unwilling to do, because it involves computer science and modeling and all sorts of ideas that can't be gotten with a scalpel/microscope/ MRI machine alone.

Like I've said, computers are great tools. I've cited a couple of studies already in which simulated neural networks were used in conjunction with brain research.

Obviously, consciousness does not depend on vision. So, we expect that the patterns seen in the anesthesia study, for instance, hold for seeing and blind patients.

This fact does not, in any way, hamper brain research on consciousness. And obviously, much of that research will focus on operations that seeing and blind people have in common.

Nor does it mean that computer simulations are of no value. It's just that folks are doing a lot more with computers than happens to be on-topic for this thread.

 

[Jeff Corey]

I left my book again, but I'm pretty sure he was referring to his own split brain studies there. This guy is Michael Gazzaniga, btw. (And you've got some damn smart students!)

I can't believe Gazzaniga would say such a thing as"With special equipment, you can tell the right hemisphere to do something by giving a visual command to one eye, such as "pick up a banana."
Are you sure he stated that?

First, no special equipment is needed to present a visual command to one eye. An eyepatch or some duct tape would do the trick.
Second, stimuli presented to one eye would end up in both occipital lobes because of the hemidecussation of the optic nerves at the optic chiasma.
Third, most students were able to answer the question on tests that asked ""In the "split brain" operation, the person's __________ ________ is severed. Because most people process speech in the ____ hemisphere, that means they can not name objects in the ____visual field."

 

[rocketdodger]

Now, I will say, tho, that inferences can get dicey pretty quickly. For instance, I don't know of any way to be sure that consciousness is actually involved in the process of being put on notice to be on the lookout for something, or is simply aware of it.

Have you thought about it?

Because if do think about it, it becomes apparent that the distinction between "put on notice" and "simply aware" is rapidly muddied, to the point where the phrases "put on notice" and "simply aware" don't even mean anything.

 

[Piggy]

Have you thought about it?

Because if do think about it, it becomes apparent that the distinction between "put on notice" and "simply aware" is rapidly muddied, to the point where the phrases "put on notice" and "simply aware" don't even mean anything.

Yeah, I agree with that.

 

[Piggy]

I can't believe Gazzaniga would say such a thing as"With special equipment, you can tell the right hemisphere to do something by giving a visual command to one eye, such as "pick up a banana."
Are you sure he stated that?

First, no special equipment is needed to present a visual command to one eye. An eyepatch or some duct tape would do the trick.
Second, stimuli presented to one eye would end up in both occipital lobes because of the hemidecussation of the optic nerves at the optic chiasma.
Third, most students were able to answer the question on tests that asked ""In the "split brain" operation, the person's __________ ________ is severed. Because most people process speech in the ____ hemisphere, that means they can not name objects in the ____visual field."

That's how it is in the Harper Collins edition of Human. Could be that the words "one half of" were omitted ("by giving a visual command to one half of the eye") and not noticed, or that only one eye was used... I'm pretty sure I recall Gazzaniga using equipment to present commands to half the visual field.

 

[Piggy]

Heard a very interesting Radio Lab segment on the subject of consciousness today.

You can find it here.

Piece on / interview with Christof Koch.

One of the hallmarks of properly functioning consciousness is coordination (e.g. the McGurk effect, which is clearly the result of pre-conscious activity because the sound we hear can't be "flipped" like, say, a stick-figure cube).

And we don't see colors, really, we see things that are certain colors. Actual experience of a color without a thing to be that color is difficult to imagine (although that's what some folks experience).

The piece/interview references the case of a woman who occasionally lost her time/motion coordination, and her experience of motion would freeze, although her sense of the passage of time was intact.

By the time we're consciously aware of anything, it's become some particular kind of thing that we're capable of being consciously aware of (hence the time lag noted elsewhere -- the binding takes time) which is determined by how our brains are built, which is determined by evolution.

Our brains are born with a way of understanding the world, in terms of objects, animals, plants, relationships, probabilities, and physics. The better we get at testing babies, the younger we find this innate way of dealing with the world.

Other brains are different. Bird brains may well have an experience of magnetic fields that is impossible for primate brains to imagine.

Anyway, Koch is apparently finishing up Crick's final work, and it sounds like they're talking about a potential candidate for the brain real-estate that may be responsible for doing the coordination. Should be interesting.

 

[Piggy]

The concept of fluidity is popping up a lot in what I'm reading. (Links appreciated)

Here's a little random thing, Creating Simplicity: How Music Fools the Ear

It suggests that the compressability of Beethoven's music is at least part of what makes it enjoyable, and that the compressability of all music is part of what makes it more enjoyable than static.

Fwiw, studies cited in Human concur that fluidity -- i.e., the brain's ability to recognize things quickly and easily -- is highly correlated with, well, liking stuff.

I love all this technical jargon.

Anyway, to wax philosophical, I wonder if we might get a special kick from a situation in which the conscious mind perceives something as complex but for other areas of the brain it requires a small investment. That could be the basis of a joy in solving problems, which has a clear evolutionary advantage.

 

[Varanid]

our brains are built to quickly recognize certain things, such as snakes,

Got a source for that (asked in completely non-antagonistic way)?
You may very well be right, but my experience is quite the opposite. Most people are terrible at resolving a snake in situ.

No derail intended, just curious.

 

[Piggy]

Got a source for that (asked in completely non-antagonistic way)?
You may very well be right, but my experience is quite the opposite. Most people are terrible at resolving a snake in situ.

No derail intended, just curious.

Oh, I don't mean we recognize what kind of snake, just that we recognize snakes. In fact, we over-recognize snakes (react to snakelike things that turn out not to be snakes).

We share this behavior with a few other species.

I've got print cites, not necessarily links, if you still want them.

ETA: Btw, I don't at all mind being asked for sources, and that's never a derail as far as I can see.

 

[Dancing David]

Piggy, Just as an aside, our brains are built to recognise patters, I am not sure that the patterns fro spiders or sankes are hardwired with any preferences.

 

[Piggy]

Piggy, Just as an aside, our brains are built to recognise patters, I am not sure that the patterns fro spiders or sankes are hardwired with any preferences.

It certainly seems to be the case for snakes.

Also, I recently read about a study on wombats who have been isolated from predators on an island for nearly 10,000 years, and they still have a freeze response to stuffed predators but not to other stuffed animals or objects.

 

[Piggy]

Human deals with all sorts of brain matters, not just consciousness, but the current chapter I'm on is explicitly on consciousness, so I thought I'd post a few key passages. (I highly recommend reading the entire book, btw.)

In each case, ellipses indicate an omission, and any bolding is mind.

Before delving into what is known about the basic neural architecture of consciousness, Gazzaniga opens with a discussion of intentionally altered states of consciousness, then moves on to natural variations in state:

.... We are always tampering with an aspect of our existence we still can't define: phenomenal conscious experience.

Consciousness comes in many flavors. Anyone who has taught an introductory college class... has seen them all. There may be a couple of party-hearty frat boys in the back row, dozing.... These two are not conscious. Up a couple of rows is the scammer checking out the hot babe across the aisle.... He is conscious, but not of you; nor are the three girls down the way who are passing notes to each other and suppressing their merriment. Another has a tape recorder going and is finishing up a paper for another class, and will be conscious of you later. The front-row kids are sippin' their coffee, taking notes furiously and occasionally nodding in agreement; at least they are conscious of you....

We have talked about two aspects of brain function: the non-conscious goings on and the conscious goings on, the latter being what... Michael Posner... calls alertness. We have already seen that a considerable amount of processing, one might even say most of it, occurs without our being aware of it undercover. It hasn't been easy figuring out the content of all the nonconscious goings on that have been elucidated so far, for the simple reason that it doesn't bubble up to our consciousness. Researchers have had to devise tricky experiments to reveal their presence.

From there, he considers the "[mystery of] how a perception... enters into consciousness from the nonconscious depths", and adopts Antonio Damasio's division between "core consciousness" and "extended consciousness".

Core consciousness is what goes on when the on-off switch is flipped on and an organism is awake and aware of one moment, now, and one place, here. It is alert and not concerned with the future or the past. This consciousness is not aware of self and is not uniquely human. It is, however, the foundation that is necessary to build increasingly complex levels of... extended consciousness..... The highest level is knowing... what that cake will do to your waistline, and caring. I know for sure that dogs do not care about their waistlines.

From there, he begins discussing the architecture, beginning with "the 'on' switch" in the brain stem. I'll pick up there later, gotta go back to work now.

 

[Beelzebuddy]

You mean the reticular activating system, I'm sure. You should just read the wikipedia link; it'll be shorter, more informative, and less filled with only mostly-accurate layspeak.

I'm still not sure what we're supposed to be talking about here. This whole topic seems to be your personal notes on reading some other book which marginally-correctly summarizes other papers. The papers are there. Read them, draw your own conclusions, so you don't have to depend on an appeal to authority. Or at least read to the end of the book first and tell us what his conclusions are so we can talk about them instead.

 

[Piggy]

You mean the reticular activating system, I'm sure. You should just read the wikipedia link; it'll be shorter, more informative, and less filled with only mostly-accurate layspeak.

I'm still not sure what we're supposed to be talking about here. This whole topic seems to be your personal notes on reading some other book which marginally-correctly summarizes other papers. The papers are there. Read them, draw your own conclusions, so you don't have to depend on an appeal to authority. Or at least read to the end of the book first and tell us what his conclusions are so we can talk about them instead.

Gazzaniga does a really good job of pulling it all together. As for his being only marginally correct, I mean, come on, the guy's a top researcher in the field, published out the wazoo, he knows what he's talking about.

And layspeak's fine with me, as long as it gets the idea across.

I'm posting some from Human, some from articles in The Cognitive Neurosicences, and some from online sources like Science Daily. Whatever I run across that fits.

The 8th chapter of Human is entirely about the topic of this thread, so I'm going to post the key points here. (No book reports, I always hated them.)

For some, these points will be well known already, and not of much interest. On the other hand, that's not going to be true for everybody.

Of course, if you're tired of it being only me posting stuff, you could post something on brain research into consciousness, but unless I read you wrong -- and maybe I do -- you don't think the field is much worth talking about, correct?

ETA: Well, obviously that's wrong, because you just did post a link on the brain and consciousness. Sorry about that, my apologies.

This thread may wind up becoming my personal notes vault, I suppose, or if enough interesting stuff gets posted, a few more folks might come across it who join in.

 

[Beelzebuddy]

Of course, if you're tired of it being only me posting stuff, you could post something on brain research into consciousness

... you've never actually read a single thing I posted beyond what it took to make a token response, did you?

 

[Piggy]

... you've never actually read a single thing I posted beyond what it took to make a token response, did you?

In fact, I was just about to start a post with "This will overlap somewhat with Beelzebuddy's link...."

Look, I'm sorry I was a snot early in the thread. I was just paranoid about things spinning off into zones where I've seen other threads go.

The thing is, it seems unlikely to me that we're going to disagree about what goes on in the brain. I doubt we have a substantive difference.

 

[Piggy]

This is going to overlap somewhat with Beelzebuddy's link, and the diagram there will be useful.

Gazzaniga starts with groups of neurons in the brain stem, of course (emphasis from original).

Some are required for consciousness, and those are connected with the intralaminar nuclei (ILN) of the thalamus. Others are required to modulate consciousness, like a rheostat; they make up part of the arousal system. These are connected to the basal forebrain, the hypothalamus, and directly to the cortex.

Footnote: The basal forebrain is located where the name implies... near the base of the front of the brain. These structures are important in the brain's production of a chemical widely distributed in the brain called acetylcholine, which affects the ability of brain cells to transmit information to one another. Basal forebrain neurons that use acetylcholine... are involved in attention and memory. Inhibiting these chemicals is one of the mechanisms that causes sleep. Recently it has been shown that the posterior hypothalamus also plays a major role in arousal and sleep, and has neurons that act like a toggle switch... or a "flip-flop" circuit between wakefulness and sleep.

He discusses the minimum hardware required for core consciousness, beginning with "the neurons that connect the brain stem with the intralaminar nuclei of the thalamus".

There are two ILNs in the thalamus, one in the right side and one in the left. The thalamus itself... sits astride the midline, smack dab in the center of the brain. Small, strategically placed bilateral lesions to the ILN in the thalamus turn consciousness off forever, although a lesion in one alone will not. If the ILNs of the thalamus don't get their input from the connections to the brain stem, they are likewise kaput. So we have the first step on the road to consciousness: The connection of the brain stem to the thalamus must be active, and at least one of the ILNs must be up and running.

So where from there?

Neuronal connections link [the thalamus] to specific regions all over the cortex, and those regions send connections straight back to the thalamus. It has connection loops, which will become important a little later.... The ILNs themselves connect to the anterior portion of the cingulate cortex. Lesions anywhere from the brain stem to the cingulate cortex can disrupt core consciousness.

But at the cingulate cortex, just above the corpus callosum connecting the two hemispheres, "core consciousness and extended consciousness overlap".

Damasio reports that patients with lesions in their cingulate cortex have disuprtions in both core and extended consciousness, but oftentimes can recover core consciousness.

.... During the performance of conscious tasks, connections from the cingulate cortex to brain areas supporting the five neural networks for memory, perception, motor action, evaluation, and attention activate.... While engaging in a wide assortment of conscious tasks that require different types of brain activity, another area of the brain also is always activated, along with the anterior cingulate cortex (ACC). That was [sic] the dorsal lateral prefrontal cortex (dlPFC). And it is no coincidence that these two areas have reciprocal connections -- more loops.... And... the dlPFC is also a hotbed of connections to the same five neural networks mentioned above.

From there, he moves on to "extended consciousness and modularity".