How the Brain Does Consciousness: Biological Research Perspectives

[Piggy]

What evidence is there that what we think is "now" is actually half a second ago? It sounds reasonable to me, but I don't know how you could possibly go about testing it. The only experiments I've ever heard of had, in my opinion, questionable methodology.

Well, first of all, there's just the mechanics of the situation. We're not aware of raw input, but rather of highly coordinated internal impulses well downstream from the input.

Take, for example, the McGurk effect:



This demonstrates that our experiences are post-filtering, post-coordination, and that takes time due to neural distances.

The phenomenon of emotional blindness is a similar example, in which people have emotional responses but are not aware of their emotional states. That's because the neural pathways which make emotional states available to conscious awareness are downstream from the pathways that allow us to have emotional reactions.

The emotion comes first, then the feeling. (Although we tend to think of the two as one and the same.)

I don't have any of the experiments at hand which have resulted in the (roughly) half-second measurement, but perhaps others here will have some links.

 

[Beelzebuddy]

I had intended for the following to be my first post in the forum, but by the time the staff eventually got around to approving my registration, the causative thread had quite dropped off and trust me, it wasn't worth bumping. Still, enjoy.


Somewhere in Beelzebuddy's frontal cortex, a neuron fired.

The firing of the neuron was random, like a coin flip is random. That is, not TRULY random, not a quantum process - the temperature was high enough to quickly collapse any putative waveform - but difficult to predict. If you knew every eddy of the local atmosphere, you could correctly call a coin in the air, and if you knew the state of every afferent onto this neuron, you likewise could have accurately predicted this event.

The neuron's activity didn't mean much by itself. It had already fired several times that second. Its efforts had been wasted, like Twilight fanfiction, half its action potentials stillborn due to lateral inhibition and the other half falling on deaf ears. So to speak.

This time was different. This time, the prevailing local activity responsible for fueling the inhibitory gating was unstable from fighting homeostatic mechanisms for the last second or so. This time, our neuron activated one of its peers, which had itself almost decided to fire and was teetering on the brink. Then it and its buddy excited a mutual colleague. Then another, and another. Old friends, whose long-acetylated tubulin circuity had been lying dormant for just this moment. New acquaintances, whose active synapses were so fresh they hardly had any molecular infrastructure at all.

One neuron acting alone means nothing. But a million neurons in sync make a Pattern.

Within a few hundred milliseconds, the growing mosaic of activity had gathered enough momentum to wrest control of the lateral inhibitory system from the dominant pattern. Armed with inhibition, our new pattern could dampen any upstart cells trying to wrest their throne in a similar fashion. The unexpected strength of the pattern spurred the supporting glial network into action as well, which dilated capillaries for more oxygen, swept up stray neurotransmitter, and generally stabilized the system. This activity was in it for the long haul: 5, maybe even 10 seconds. Though it was top dog for the moment, the pattern had to work fast. Already homeostasis, a catchall term for the brain's myriad stalwart defenses against obsession and epilepsy, was beginning to set in.

Like the firing of the first neuron, the pattern was seemingly random, but really not. In another frontal cortex, or in another part of Beelze's brain, it would have been meaningless nonsense. Yet it had formed again and again in the past, with minor variations each time, in response to similar stimuli. This active pattern wasn't caused by a thought, and it didn't cause a thought. It was a thought. Someone familiar with Beelze's cortex, watching the activity build, would have known at once what it meant: that someone was wrong on the Internet.

Communication with the other lobes linked desire to detail. Where? The hippocampus (aided by the temporal lobe) chimed in: the Randi forums. Who? The parietal cortex wasn't too sure about this, but it had to be someone. Y'know, people. About what? According to a different bit of the frontal cortex, the brain's function and "consciousness," possibly the second most misunderstood and abused scientific term after "quantum."

The active patterns tried to engage the motor cortex, but couldn't muster the pep. Freakin' everything tries to hit the motor cortex, it wasn't about to get into gear over a bit of nerdrage. Luckily, just then aid came from an unexpected source - collaterals down to the left amygdala had returned with a fresh supply of outrage. THAT was worth acting on. Now something had to be done.

But, like so many other things, it couldn't be done immediately. There was a great deal of prep work to do first, and it had been a long few seconds. For now, the pattern was content to die back in favor of its successor, a thought which went something along the lines of "now how the hell do I register on this forum?"

This post brought to you in part by the pathetic fallacyTM. The pathetic fallacyTM: it wants to be used!

 

[Piggy]

One of the key principles to keep in mind regarding the brain and consciousness is that the brain can do quite a bit more than folks generally think it can without referring anything through the modules responsible for conscious awareness.

One of the most surprising experimental results, for me, is that people with certain types of blindness can sense a person's emotional state from their facial expressions, without even being aware that they're looking at a face (except for the fact that they've been told that they are).

This works because our ability to read faces -- presumably because it is so important from an evolutionary point of view -- doesn't bother with the relatively slow routes through the conscious modules.

In fact, we engage in unconscous mimicry of other people's body language in a much narrower time frame than is possible for any behavior involving conscious awareness.

With faces, impulses that allow us to associate an expression with an emotion take a short-cut to the amygdala, so that even if the connection to the visual cortex is severed, a person still gets a sympathetic resonance, and can guess the emotion of the face s/he's not even aware that s/he's seeing.

 

[Earthborn]

RadioLab reported on the underlined part. Experiments indicate this is a retroactively constructed illusion.

Really? I wonder how they figured that out. It seems quite relevant to the topic and would further show that we can't really trust our idea of when consciousness starts and stops. Do you have a link?

Can I interject at this point and say that "sofia", both as an acronym and expanded, is an absolutely horrible term?

I think it is a cute acronym, but a useless term in these discussions. When talking about a difficult to define philosophical concept such as "consciousness", the discussion doesn't become clearer by someone insisting on using a term consisting of four other problematic philosophical concepts. And for someone wanting to discuss "the science not the philosophy" (whatever that means) of consciousness it seems exactly the wrong term. "Sofia" is the greek word for wisdom, and the source of the word filosofia.

True, but research demonstrates that consciousness is a resource hog.

Which research?

One of the most surprising experimental results, for me, is that people with certain types of blindness can sense a person's emotional state from their facial expressions

I am assuming you mean a type of blindsight where people can see but not be consciously aware that they are seeing. Calling it a type of blindness is confusing, as that would suggest the eyes aren't functioning. It is more a type of seeing.

 

[Earthborn]

If consciousness is really such a resource hog, and the brain can do such a lot without it, it seems likely to me at least some people live without it. Natural selection isn't 100% effective at weeding out the most crippling conditions, so it is difficult to imagine how weed out an effective way to save energy.

Piggy's idea of consciousness raises the question: is a P-Zombie not only theoretically possible, but could it arise out natural influences? It also offers a way to answer the question, because it allows us to distinguish between P-Zombies and non-P-Zombies.

All we have to do is measure how much energy their brain uses. If consciousness is such an energy intensive process and it is theoretically possible to have a functioning brain that doesn't have it, then we should be able to find people whose brain uses vastly less energy.

 

[Squeegee Beckenheim]

Well, first of all, there's just the mechanics of the situation. We're not aware of raw input, but rather of highly coordinated internal impulses well downstream from the input.

Take, for example, the McGurk effect:



This demonstrates that our experiences are post-filtering, post-coordination, and that takes time due to neural distances.

The phenomenon of emotional blindness is a similar example, in which people have emotional responses but are not aware of their emotional states. That's because the neural pathways which make emotional states available to conscious awareness are downstream from the pathways that allow us to have emotional reactions.

The emotion comes first, then the feeling. (Although we tend to think of the two as one and the same.)

I don't have any of the experiments at hand which have resulted in the (roughly) half-second measurement, but perhaps others here will have some links.

As I've said twice now, it seems to make sense. But what I'm asking for is the actual experimental evidence that this is the case.

 

[ThunderChunky]

The word "consciousness" has various usages. For the purposes of this thread, the stipulative definition of the term is a functional one: Consciousness is what our brains are doing when we're awake, and when we're dreaming, which it is not doing when we're asleep and not dreaming or in a profound state of anesthesia. In other words, it's what our brains begin to do when we wake up from a dreamless sleep, and what they stop doing when we fall into dreamless sleep or are put into deep anesthesia or pass out.

How useful is that definition? Maybe you could expand on it. Saying consciousness is "what the brain does" seems rather weak and circular.

Fortunately, my body is smart enough to take action before I'm consciously aware.

That reminds me of an interesting metaphor. Consciousness is like a man riding an elephant (which is the unconscious processes). The rider can guide the elephant and is aware of what the elephant is doing in the moment. At times the rider feels like he is in control of the elephant, but if the elephant wants to do something...there is no stopping it.

 

[MuDPhuD]

Beerina's link to Francis Crick's research is the only actual science so far in this thread. I saw him speak (at the Society for Neuroscience convention) on this research long ago, but haven't heard of any breakthroughs over the past 15 years. He was the only hard core Neuroscientist at the time who had the guts to proclaim "CONSCIOUSNESS NOW" and actually implement a neurophysiological investigation of consciousness. Most people at the time thought he had gone off the deep end, and maybe he had.

Thanks for reminding me. I'm going to look into it.

BTW, How we Decide, by Jonah Leher, is an interesting book which talks extensively about the unconscious activities of our brains and their influence on consciousness. Our conscious awareness is only the tip of the iceberg that is brain activity.

 

[ThunderChunky]

How useful is that definition? Maybe you could expand on it. Saying consciousness is "what the brain does" seems rather weak and circular.

As a followup, is there an objective way to measure whether something or someone is in a 'conscious' state?

 

[nescafe]

Somewhere in Beelzebuddy's frontal cortex, a neuron fired.

<stuff>

One neuron acting alone means nothing. But a million neurons in sync make a Pattern.

<more stuff>

Someone familiar with Beelze's cortex, watching the activity build, would have known at once what it meant: that someone was wrong on the Internet.

<even more stuff>

Freakin' everything tries to hit the motor cortex, it wasn't about to get into gear over a bit of nerdrage.

I salute you, sir.

 

[Piggy]

Which research?

Well, this research, for example: Brain Energy Use Key To Understanding Consciousness

High levels of brain energy are required to maintain consciousness....

 

[Piggy]

I am assuming you mean a type of blindsight where people can see but not be consciously aware that they are seeing. Calling it a type of blindness is confusing, as that would suggest the eyes aren't functioning. It is more a type of seeing.

These people are blind. Impluses from their sensory apparatus cannot be transmitted to the areas of the brain responsible for conscious awareness. They have no awareness at all of anything they're seeing.

If you were in this state, you would certainly consider yourself blind.

Of course, this is not the same physical damage as, say, folks have whose eyes are absent.

But it is this particular type of blindness that can tell us something about how consciousness operates in the brain, which is why I reference it.

Not all of the impulses from the eyes travel the same path as do the impulses involved in recognizing emotions from facial expressions, and this is precisely why it is interesting and informative for studies of consciousness.

 

[Piggy]

Piggy's idea of consciousness raises the question: is a P-Zombie not only theoretically possible, but could it arise out natural influences? It also offers a way to answer the question, because it allows us to distinguish between P-Zombies and non-P-Zombies.

I am going to have to call you out here for posting off-topic.

This thread is very explicity about brain research and how such research contributes to our understanding of consciousness.

You are now leaving that topic and delving into an area which many other threads have dealt with, but which is clearly off-topic here.

If you want to discuss p-zombies, there are plenty of other places where you can have such a discussion, but this isn't one of them.

Thanks.

 

[Piggy]

As I've said twice now, it seems to make sense. But what I'm asking for is the actual experimental evidence that this is the case.

As I said in the post you cite, the McGurk effect is evidence in that regard, but I don't have at hand a citation for the actual measurement; perhaps others here will be able to provide that for you.

 

[Piggy]

How useful is that definition? Maybe you could expand on it. Saying consciousness is "what the brain does" seems rather weak and circular.

Regardless, that is the stipulative definition offered for the purposes of this thread. (You may want to read the link provided by Beerina for a perspective on why such functional definitions are necessary at this stage of the research.)

If you would like to have a discussion using a different stipulative definition, then I would recommend starting a separate thread.

Thanks.

 

[Piggy]

As a followup, is there an objective way to measure whether something or someone is in a 'conscious' state?

We're getting there.

See, for example, this study identifying signature brain waves associated with conscious states.

 

[Piggy]

Here're some suggestions

A few points from the article that I'd like to call out here:

We think that most of the philosophical aspects of the problem should, for the moment, be left on one side, and that the time to start the scientific attack is now.

This is the tack also intended by this thread.

That does not mean that other approaches are not valid. It's just that this particular thread is concerned with biological approaches, specificially the insights arising from research on animal brains. That's what this thread is about.

It is probable that at any moment some active neuronal processes in your head correlate with consciousness, while others do not; what is the difference between them?

Gazzaniga describes the problem, which he calls the "explanatory gap", this way: Even if we were to discover all of the neural correlates of consciousness (NCCs) tomorrow, we would still have no way of determining why any particular neural state is correlated with a particular conscious experience and not some other conscious experience or no experience at all.

Given that fact, we have obvioulsy not yet discovered the theoretical framework which will allow us to understand how the brain creates consciousness.

Gazzaniga compares it to the ancients' inability to connect sound, light, and the ripples on a pond, which to us are tied together by the notion of waves.

We know that not all of the brain's activity is involved in the production of conscious awareness. And we have some experimental evidence that is beginning to clarify that distinction. But it's early yet.

What's surprising, in fact, is the range of ability of the non-conscious modules, which can perceive, remember, act, and even learn.

Everyone has a rough idea of what is meant by being conscious. For now, it is better to avoid a precise definition of consciousness because of the dangers of premature definition. Until the problem is understood much better, any attempt at a formal definition is likely to be either misleading or overly restrictive, or both.

This is still the case more than a decade later.

When one clearly understands, both in detail and in principle, what consciousness involves in humans, then will be the time to consider the problem of consciousness in much simpler animals. For the same reason, we won't ask whether some parts of our nervous system have a special, isolated, consciousness of their own. If you say, "Of course my spinal cord is conscious but it's not telling me," we are not, at this stage, going to spend time arguing with you about it. Nor will we spend time discussing whether a digital computer could be conscious.

This is merely one of the reasons why the issue of conscious machines is excluded from this thread.

Self-consciousness -- that is, the self-referential aspect of consciousness -- is probably a special case of consciousness. In our view, it is better left to one side for the moment, especially as it would be difficult to study self-consciousness in a monkey.

Ditto.

The remainder of the article discusses visual consciousness in particular, which is a more narrow topic than this thread is open to, so I will stop there, although I recommend the article to anyone interested in the subject.

 

[Earthborn]

Well, this research, for example: Brain Energy Use Key To Understanding Consciousness

Note that these researchers use a different definition of consciousness than what you are using:

At its simplest, consciousness can be defined as the ability to respond meaningfully to external stimuli.

In fact it is the sort of consciousness that you said you didn't want to talk about:

For the purposes of this thread, consciousness does NOT mean only "waking awareness"

Also the study is done on rats, for which it is an open question whether they have the "Sense of Individual Awareness" you are describing. Lastly it is done by scientists who are not so sure consciousness is a property of the brain...

The finding has profound implications for our understanding of the connection between the brain and consciousness, Shulman said. "You can think of consciousness not as a property of the brain, but of the person."

... even though you said you want to limit the discussion to the brain.

We're getting there.

See, for example, this study identifying signature brain waves associated with conscious states.

Doesn't seem relevant to the kind of consciousness you want to talk about either. No attempt is made to determine whether the same things occur during dreaming.

If you were in this state, you would certainly consider yourself blind.

Yes, I would consider myself blind. But blindness in these people is sort of an illusion; as they can respond meaningfully to visual stimuli.

Not all of the impulses from the eyes travel the same path as do the impulses involved in recognizing emotions from facial expressions, and this is precisely why it is interesting and informative for studies of consciousness.

I agree that it is tremendously interesting, but I am not so sure it tells us a lot about the nature of consciousness yet. It seems to me more of a problem research into consciousness has yet to tackle.

You are now leaving that topic and delving into an area which many other threads have dealt with, but which is clearly off-topic here.

I don't think it is off-topic. It is relevant to your claim that consciousness is a "resource hog" and that yet natural selection has favoured it. If it really requires so much resources, then there must have been times and places where it wasn't favoured and it would be likely that there is considerable variation in consciousness in humans.

 

[Piggy]

As I've said twice now, it seems to make sense. But what I'm asking for is the actual experimental evidence that this is the case.

Here is one article that you might find interesting on that point.

Now You See It, Now You Know You See It

There is a tiny period of time between the registration of a visual stimulus by the unconscious mind and our conscious recognition of it -- between the time we see an apple and the time we recognize it as an apple. Our minds lag behind our eyes, but by how long? And how does this affect our reactions to the world around us?

Some estimates say the time delay lasts only 100 milliseconds, others say 500 milliseconds. A new study by Tel Aviv University psychologists says that the answer is somewhere close to the latter, but can vary depending on the complexity of the stimulus....

 

[Piggy]

A couple of articles regarding the abilities of the brain to perform tasks without involving the modules that handle conscious awareness:

Unconscious Learning Uses Old Parts of the Brain

A new study from the Swedish medical university Karolinska Institutet provides evidence that basic human learning systems use areas of the brain that also exist in the most primitive vertebrates, such as certain fish, reptiles and amphibians. The study involved an investigation into the limbic striatum, one of the evolutionarily oldest parts of the brain, and the ability to learn movements, consciously and unconsciously, through repetition....

Subliminal Learning Demonstrated In Human Brain

Although the idea that instrumental learning can occur subconsciously has been around for nearly a century, it had not been unequivocally demonstrated. Now, a new study published by Cell Press in the August 28 issue of the journal Neuron used sophisticated perceptual masking, computational modeling, and neuroimaging to show that instrumental learning can occur in the human brain without conscious processing of contextual cues....