SGU Episode 409
|
This episode needs: transcription, links, 'Today I Learned' list, categories, segment redirects. Please help out by contributing! |
How to Contribute |
| SGU Episode 409 |
|---|
| 18th May 2013 |
 |
| (brief caption for the episode icon) |
| Skeptical Rogues |
| S: Steven Novella |
B: Bob Novella |
R: Rebecca Watson |
J: Jay Novella |
E: Evan Bernstein |
| Guest |
HB: Heather Berlin |
| Quote of the Week |
Every kid starts out as a natural-born scientist, and then we beat it out of them. A few trickle through the system with their wonder and enthusiasm for science intact. |
| Links |
| Download Podcast |
| Show Notes |
| Forum Discussion |
Introduction
You're listening to the Skeptics' Guide to the Universe, your escape to reality.
This Day in Skepticism (01:27)
- May 18 1896: 1300 people were trampled to death at a celebration for Nicholas II when a rumor spread that there wasn't enough beer and pretzels for everyone.
News Items
Your Senses in Space (05:27)
Talking Plants (14:48)
Flowing Glass (19:14)
- National Geographic: Fossil Amber Challenges Theories About Glass
Book Review: Ender's Game (24:25)
Who's That Noisy? (30:14)
- Answer to last week: Desert Rain Frog
Questions and Emails
Question #1: Water Heaters (32:37)
- What is the proper temperature for a home water heater?
Question #2: Atacama Specimen (34:00)
- We received many questions about the 6 inch alleged alien known as the Atacama Specimen.
Advertisement for Euro Skeptics' Congress (40:07)
Interview with Heather Berlin (41:00)
S: Joining us now is Heather Berlin. Heather, welcome to The Skeptic's Guide.
H: Thank you! I'm great to be here.
S: And Heather is an assistant professor of psychiatry and neuroscience at Mount Sinai School of Medicine. She just gave an excellent talk at NECSS this year, where we met her for the first time, and just had to have her on the show. So thanks again for joining us.
So Heather, you're a neuroscientist with an interest in the neurological basis of mental illness; but you also wanted to chat with us tonight about the neuroscientific basis of consciousness. So why don't you tell us about that?
H: Well, what first got me interested in neuroscience was this conundrum. When I discovered myself in the world and having all of these experiences and feelings and emotions, I just found myself here, and thought, where do all these thoughts come from? So I was quite young. I remember I was about five years old. And I asked my father one day, I said, “Where do my thoughts come from? And can I keep them when I die?” Because I had this sort of obsession with death.
Well, he said, “They come from your brain.” And I said, “Well, how?” And he said, “Well, I'm not quite sure. But maybe when you grow up, you should become a psychiatrist and figure that out.” So, that wasn't really where all the answers were, but that began my quest to try to understand how our brain creates out thoughts and our consciousness and our awareness.
And my quest was kind of trying to cheat death. As I went on through my studies, I did discover that when the brain goes, your thoughts go. But I remain fascinated with how they're interrelated and connected.
S: So tell me how you conceptualize how the brain produces consciousness. I know there isn't any one final answer to that. But how would you explain that?
H: Well, there are a lot of different theories out there. There's the sort of main question this field is trying to understand what they call the neural correlates of consciousness, which means that any thought, percept, feeling, has a distinct set of neurons that fire – for example, give you the sensation of seeing the color red, or smelling a rose.
What neuroscientists are trying to do now is to track the specific set of neurons that correspond to any one percept. So with modern technology, we're getting closer and closer to be able to do that. Once we can solve that problem; once we can say, map out the neural correlate to every thought you have, the next question becomes – they call it the easy problem – the next question is what they call the hard problem; and that is, why is it that these neurons firing, and these neural transmitters slushing around, how does that correlate to this what feels as a metaphysical perceptions.
And we might not ever be able to understand that fully. At least some people say that we might never be able to understand that because we're sort of limited by the very apparatus that we're trying to study. We're limited by cognitive capacity of our brain to understand how the very thing works.
S: Yeah, that's what philosophers call qualia. Why do we actually experience red? And what's the difference between neurons firing in our brain, doing some calculation, and other neurons firing and giving us something that we subjectively experience.
My personal take on it, I like Daniel Dennett's approach in that, well maybe there's not really -
B: P-zombie?
S: He does not agree with the p-zombie idea. He thinks that there is no hard problem; that once you solve all the easy problems, that's consciousness. It's an emergent property, and there is nothing else that you need to explain. Do you know what I mean? What are your thoughts on that?
H: Yeah, it's a very popular view. I think it kind of explains away the problem, but it's not very satisfactory, at least to me, because he almost explains away consciousness itself. And I've had some discussions with him. For example, the idea of the experience one has of pain. He'll say that's almost an illusion. You're not actually experiencing pain.
You get into these philosophical debates. And I, as a neuroscientist who just tries to look at the data – but one theory of consciousness that I like, and it's becoming increasingly popular in the world of conscience research is a theory by someone named Giulio Tononi called the integrated information theory of consciousness.
And that idea is basically that any system that has a high degree of differentiated integrated information has some level of consciousness. And he has this calculation which he calls phi. It's a measure of consciousness. So basically, it means consciousness is substrate-independent. So you could have it in a brain because it happens to be a system that has a high degree of integrated differentiated information.
But it can also eventually be in a computer. So it's substrate-independent. And it's an information processing type of theory of consciousness.
B: How substrate-independent are we talking? Could you have tinkertoys that, if it's big and complex enough, could it experience some level of consciousness?
H: Yeah. But the problem is it would have to be so complex, it would be very difficult. You'd have to have tinkertoys that probably go from here to the Moon and back again to get to such a level of complexity that it has any kind of an experience.
So, the criticism of Giulio's view is that it borders on panpsychism because basically it means that anything can have some degree of consciousness. And then consciousness loses its meaning, because if any system can have let's say a low degree of what he calls phi, which is a measure of consciousness, then what does this really mean? Then anything can have a certain degree that any system, no matter how small, would have a certain level of consciousness. So that's sort of one of the criticisms.
J: Heather, I think we need to define system a little bit because when you used the idea of say, building this really complicated system of legos or whatever, that was Bob's example, I would imagine that there are a few things that have to be present. The consciousness has to be able to communicate to different components of itself. And the workings of our brain uses electricity to communicate to itself, and to do what it does, right?
So I would imagine that you'd need some type of way for those components to communicate with each other, and over long distances it would be really slow. It wouldn't be able to do what we do, right?
H: So, the example that Giulio uses, there are bits of information. So if this bit is on, how it connects to the bit next to it. But the example that he would use is that, he would say for example, you have these diodes in a camera. And if one of them goes off, the one next to it is not affected. So that would be no degree of integration of information. But if you have one bit, or let's say a neuron, and whether it fires or not affects the neuron next to it, whether that fires or not. That would be integrated information.
So you have to have a high degree across many, many bits of integrated information to create a system that is interconnected so that when one neuron or bit fires in one area, it can affect one other neuron many neurons away because the whole system is interconnected.
S: So, here's what I find unsatisfactory about that however. So, correct me if I'm wrong, but are you saying that it's merely a factor of the degree of complexity, of interconnectedness in communication? Because there are parts of the brain that are just as complex as other parts of the brain, and don't seem to have any conscious – like the cerebellum is always my favorite example.
The cerebellum's just about as complex as the cerebrum. But as far as I know, there's no cerebellar consciousness. So it's not just the complexity, the interconnectedness. It's gotta be wired to produce consciousness in some way.
H: I agree. Another one of my criticisms of Giulio's theory is that – because I'm also very interested in the unconscious. There are many, many very complex processes that are outside of awareness that go on to affect our behavior, so they're meaningful, right?
So the question is, if those processes that are occurring outside of awareness that go on to affect our behavior, they must also have a high degree of integration of information. There's a lot of complex processing that goes on outside of awareness. In fact, most of what a complex processing that occurs goes on outside of awareness.
For example, when you take in a bunch of facts, and they say “sleep on it,” basically your unconscious is processing that information. You wake up, and then you have the answer, or you have a flash of insight, right? The moment of insight.
So what I would argue is that those unconscious processes could also have a high degree of integrated information, and that would go against Giulio's theory.
S: Exactly.
H: But what he says is basically, it's a theory that needs to be tested. And if you can show that you have an hypothesis, and you can either prove it or disprove it, then you can modify the theory. The other problem with the theory is that it's so complex, it's so difficult to actually quantify this measure of phi, they can't even do it in a small system; maybe eight, I think, or twelve points of information. They're starting to try to calculate it now.
But it's so difficult to actually quantify that it's hard to use it experimentally. But the point is that at least it is a theory. It's starting to help give a framework for all the experiments that are going on in the world of consciousness research. Because ultimately we do need a theory of consciousness so we can decide whether, does a baby have it? Does a computer have it? Does a person in a comatose state have it? We ultimately need an overarching theory.
Another theory is Bernie Baars' theory of consciousness as well. There are a few theories out there. But I think you gotta start somewhere. And as a neuroscientist, you kind of just get into the nitty gritty, and start with just basic experiments to try to understand consciousness.
S: I agree with you Heather. What I'm really fascinated about is the difference between conscious and subconscious processing; what is the difference? That's the essence of the question that we're trying to answer here?
H: Yeah, so assuming that the brain is turned on. So it's important to distinguish between wakefulness – that is the brain being awake, and not being in a comatose state, or a drug-induced state, or in deep sleep. So assuming the brain is fully turned on and awake, then you can say, “Okay, you are conscious of a particular thing in the environment versus not conscious of other things that are happening.
And where does that take place? What in the neurocircuitry, differentiates something that you're consciously aware of versus what you're not aware of? And experiments are starting to sort of suss that out.
One idea is that what brings a certain percept into awareness is synchronized firing of neurons across the brain. So that is neurons firing – and usually people talk about this in a forty hertz oscillation. So in the gamma range of firing. Somehow that syncs up neurons, and neurons that kind of fire together, and they call it a coalition of neurons firing together is what you're aware of at any given moment.
And those coalitions can form and stay in consciousness for a second or two. They can last longer if you attend to something. So if you attend to something, you can keep a coalition of neurons in consciousness for longer. And then they kind of die out. And a new coalition of neurons emerges, and they're all starting to fire in sync, and fire together. So that's one theory of why certain things are conscious at any given moment versus other things.
S: So there's a certain threshold of enough neurons firing together that then you become aware of whatever it is they're quote-unquote “thinking” about. Is that what you're saying? Less than that, and that's a subconscious process that just hasn't risen to the level of awareness.
H: Yes. And it also helps what they call the binding problem. So, there's no man in the machine, where all the information comes together and there's someone's sort of viewing it like a movie, this Cartesian theater. But really, let's say you have neurons firing in the visual cortex in the auditory cortex, maybe in the motor cortex, and they're not all coming together in one place, but they're firing in these separate areas in sync, in a similar range. That's what brings them together.
J: I always understood it like the conscious part of your brain is really perched on top of all this other function, like a lot of function that's going on. It's kind of like we're experiencing a very narrow corridor of what's actually happening in our brain, because all the other supporting functions are doing all these different things that we really don't want to be aware of. They need to happen behind the scenes, right?
H: Yeah. So consciousness has a very limited capacity. Much of what's going on is happening outside of awareness. It also takes a lot of energy for things to be in consciousness. So it's a very selected bit of information that comes into awareness at any given time. Most of what's happening is happening behind the scenes.
S: And from what you're saying then, can different parts of the brain be conscious at different times? Or I guess different parts of the brain are contributing to your consciousness of the moment?
H: Yeah, I would say it more the way you said it in the latter. I wouldn't say that different parts of your brain are conscious. But I would say that different parts of your brain are contributing to consciousness more or less at any given time.
Basically, a big question is how much of the brain do you need for consciousness? Because you can get huge lesions, and the brain might work with these brain lesions, and they're still conscious. They might have specific deficits in consciousness. For example, they can't see color any more, or they can't see different things in space. But they're still aware.
So how much of the brain do you actually need for there to still be conscious awareness? And this is a question we don't know.
S: Yeah, clinically, the rule of thumb is you need your brainstem and one hemisphere. But it may be less than that. But if you have one hemisphere, you can be conscious.
H: Yeah, but I think you can have even less than that. I mean, some argue you don't even need a cortex. That's quite controversial; that I would have to disagree with. But there is evidence from children who are born without cortexes, that they have some type of what might be consciousness, or at least feeling. They might feel something.
S: Let's move now to more about your personal research involving mental illness. Can you tell us what you're doing?
H: Right now I'm doing research to try to understand the neural basis of impulsive and compulsive disorders, particularly, more recently I've been focusing on Obsessive–compulsive disorder. We're trying to understand what the neurocircuitry that's involved with the disorder so that we can hopefully develop better treatments for the disorder.
The research involves near-imaging studies. And we're also doing something called deep brain stimulation, which is a new, novel treatment for treatment-resistant OCD.
S: Can you define for us, or encapsulate what you found so far? What's the malfunction? What's happening in people who have OCD?
H: There's a number of things going on. The thing that we're focusing on is a malfunction in the subcortical part of the brain called the basal ganglia. What I'm looking at in particular is people who have contamination type OCD. These are people who have obsessions that they're going to get some sort of disease. Or they think things are contaminated, and they don't want to touch them. And then in order to relieve the anxiety that's produced by these obsessions, they engage in these compulsions like, for example, washing their hands over and over again.
What we're looking at is actually that instead of it being a top-down disorder - that is, the thoughts that are the primary thing that are controlling the disorder and causing the behavior – we think it's more of a bottom-up. And by that I mean it's a sensory processing deficit that occurs first, which then leads to the behaviors that then leads to the cognitive functions.
What we're finding is that people with contamination type OCD are hyper-sensitive to disgust, both disgusting images, and we're also doing something right now looking at odor in the scanner. And we're finding that they're hyper-sensitive to disgusting odors.
And the part of the brain that has to do with disgust is called the insula. And they have hyper-insula activation compared to healthy people.
R: What sort of odors do you use in the lab?
H: We're giving them odors of feces, of garbage, and urine.
R: Are these the actual products? Or have you formulated a synthetic feces?
H: They are synthetic. Interestingly, the OCD patients, a couple of them are very concerned. They want to know, is it the real product? Or is it synthetic? So it is synthetic, but it does smell very real.
J: Heather, I can be all those. Call me if you need me. If you need something really over the top, just shoot me an email, and I'll help you out.
H: When we run out of odors, I'll give you a call. But yeah, it's actually very novel. We built this thing called an olfactometer that we can distribute the scents in the scanner. We also give them pleasant scents as well, like banana, and chocolate, and vanilla.
So they react normally to the positive smells, but they seem to be hyper-sensitive to the negative smells. So the next step actually is we're working on this project called real-time feedback. It's basically neural feedback. They're given in real time information in the scanner. They can look at their own brain activation. And just like bio-feedback, when you're sort of given your heartbeat information, and told to do what you can to try to lower it. We're telling them the same thing.
This is your insula firing. And we show it to them in real time. And we say, “Now try to do some strategy that can get yourself to decrease that insula activation. And in healthy people, so far, they're able to do that. They can devise some sort of strategy to down regulate their insula activation. And what that does in essence is it decreases their disgust response. So the next step would be to try to do it in OCD patients using this neural feedback.
S: But do you think – so essentially here, there's a relationship between the cortex and deep regulatory parts of the brain, like the basal ganglia. And what you're saying is that you think that the primary malfunctions in the primitive regulatory parts of the brain, like the basal ganglia, and not in the cortex of patients with OCD, is that what you're saying?
H: It's a circuit. So the circuit that's involved with an OCD involves the basal ganglia and involves the cortex in particular, the prefrontal cortex is known to be involved. And now we know the insula seems to be involved as well. So it's a circuit.
For the people who are treatment-resistant – so those are people who have tried every drug, and they're very very severe. They can go in and get these electrodes implanted, which basically stimulate the parts of the basal ganglia. And they're permanently implanted. They're connected to a battery pack that's implanted just under the chest skin. And it actually stimulates these subcortical areas.
And we're not sure exactly what it's doing, if it's acting to act as a lesion, or if it's acting to stimulate a circuit that was previously faulty. But we know it's doing something to the circuitry that's problematic in OCD patients. And it's helping them.
S: Heather, I have to ask this of all of my neuroscience colleagues that I interview. So I have tangled with dualists quite a bit on my blog. And one thing they all say, whether it's Deepak Chopra or whoever is that, “Oh! Neuroscientists today know that the brain doesn't cause consciousness. They're sort of abandoning the materialist paradigm of consciousness in droves.” And yet I have yet to meet a neuroscientist who actually thinks that.
So, for the record, what's your take on dualism, and the notion of whether or not the physical processes of the brain can completely explain consciousness as a phenomenon?
H: I'm certainly not a dualist. I don't know any, not a single colleague who would claim to be a dualist. As a neuroscientist, I'm pretty much a materialist. Consciousness, there's no such thing as disembodied consciousness. Consciousness doesn't exist outside of the brain. And the brain is who you are! If you get a lesion in the brain, you have a deficit in consciousness. If you knock out the brain stem, you're no longer conscious.
It's a clear one to one correspondence, or clear relationship in that level. And I have yet to meet a neuroscientist who's a dualist. Descartes was a dualist, but he wasn't a neuroscientist, right? So, I don't know of any!
Even Freud, Sigmund Freud, who came up with this whole theory of mind, he was a neuroscientist. And he ultimately believed that all of his ideas, it is instantiated in the brain. He just didn't have the technology at that time to understand it. But he even made a little neural sketch of what he thought the neural basis of repression was.
So even one of the greatest theorists of trying to understand the minds completely believed that it was all instantiated in the brain.
S: So what you're saying is that Deepak Chopra can suck it?
(Laughter)
H: Don't quote me on that! I'll get hate letters!
S: All right. Well, Heather, thank you so much for joining us. This was a great discussion. We really enjoyed it.
H: Thank you for having me.
Science or Fiction (1:02:24)
Item #1: Corn and celery are both members of the Zea genus. Item #2: Cauliflower, mustard and turnip are all members of the same genus, Brassica. And item #3: Tomatoes and potatoes are both members of the same genus, Solanum.
Skeptical Quote of the Week (1:14:12)
Every kid starts out as a natural-born scientist, and then we beat it out of them. A few trickle through the system with their wonder and enthusiasm for science intact.
Carl Sagan
Announcements (1:14:48)
S: The Skeptics' Guide to the Universe is produced by SGU Productions, dedicated to promoting science and critical thinking. For more information on this and other episodes, please visit our website at theskepticsguide.org, where you will find the show notes as well as links to our blogs, videos, online forum, and other content. You can send us feedback or questions to info@theskepticsguide.org. Also, please consider supporting the SGU by visiting the store page on our website, where you will find merchandise, premium content, and subscription information. Our listeners are what make SGU possible.
References
|
|
|