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Science Talk August 8, 2007 -- Better Brains: The Revolution in Brain Science
Steve: Welcome to Science Talk, the weekly podcast of Scientific American for the seven days starting August 8th. I am Steve Mirsky. This week on the podcast:
Begley: If you look at the lavishly illustrated brain books, where one region is zoned for lets say, vision, that's what it now turns out can be overturned.
Steve: That's journalist, Sharon Begley, and we'll hear from her this week, plus we'll test your knowledge about some recent science in the news. Sharon Begley is senior science writer at Newsweek Magazine and she is the author of the book, Train Your Mind, Change Your Brain, [about] how a new science, reveals our extraordinary potential to transform ourselves. The conventional wisdom in neuroscience has long been that our adult brains are pretty much hardwired. By the time we are three, structure and function are pretty much fixed, but recently there's been a shift in that thinking with new experiments revealing that we not only have the ability to change the structure of our brains, but that we in fact continually grow new neurons right on through to old age. More surprising is that we change our brain—and not only through behavior, just thinking in certain ways can change structure and function. Scientific American’s Christie Nicholson recently spoke with Begley about this groundbreaking research and just what it takes to change your brain.
Nicholson: One of the center points of the book is this idea of neuroplasticity and neurogenesis, so I guess we should start by explaining what those are.
Begley: Neuroplasticity means just what the two parts of the word would suggest, neuro refers to the brain and plasticity refers to the ability of the brain to change itself, to change its structure and function. So you can think of plasticity as synonymous with malleability; and this is a quite recent realization because for more than a century, the dogma had been that the adult human brain is pretty much locked in place after, you know the ripe old age of three, in terms of its structure and function. I mean of course we could tinker around the edges, new synapses would form as we learned new skills, as we formed memories. But the basics were, as I say, very much in place and not a whole lot was changeable there, which had very depressing ramifications, when you think about it either in terms of recovery from stroke or the ability to surmount a mental illness. Again if the main message is that the adult brain cannot change in a fundamental way, then again it really limits the possibilities for human transformation.
Nicholson: And neurogenesis is that ...
Begley: Neurogenesis means the production of new neurons, again in the brain, which just as with neuroplasticity was thought to be impossible. The old idea looked at it sort of from a theoretical perspective, asking, "Well, is it reasonable to think that the adult brain could produce new neurons and if so, where would they go and what would they do?",and once the analogy of the brain as a really smart computer took hold
in. Through the '50s and '60s, people started to think, "Well, no it's not reasonable because just as you can't take a perfectly well functioning computer and throw in a bunch of wires or circuit boards at random and think that things would turn out well; well, say you can't just grow a bunch of new neurons in the brain and think that would have any beneficial effect." And again just as with neuroplasticity, that too has now been overthrown in this case, in the last decade actually, and we now know that the adult brain not only produces new neurons but that those new neurons are functional.
Nicholson: I guessed one thing that I was wondering about and wondered why the dogma had persisted for so long given that the general public, if we had said, "Well, we've discovered this new thing called neuroplasticity that the brain can change", well, you say, "Well, duh, we learn throughout our lives, we don't stop learning at the age of 20."So what is the revolutionary part of this that makes it so striking?
Begley: What the neuroplasticity revolution is saying is that if you look at the lavishly illustrated brain books, where one region is zoned for lets say, vision and another region is zoned for moving your left index finger, in other words, all of these little and large regions have specific functions, that's what it now turns out can be overturned or overruled as it were. That depending on the experiences you have, really the life you lead, that sort of new fangled phrenology indeed can be overwritten. It can be erased. New functions can be assigned to existing structures and similarly if a particular circuit is overactive or underactive, that too is amenable to change. And in many cases if those circuits had been the basis for, lets say, mental illness. And I use that example only because it’s the best studied; again, you are not stuck with that overactivity or underactivity.
Nicholson: Yeah! One of the striking pieces of research—and you cover a tremendous amount of literature in the book—is that this idea that the visual cortex—which has always been assumed to be for vision and strictly that—actually can change its function.
Begley: That was one of the most astonishing things. The visual cortex is this huge chunk of real estate in the back of your brain; it's basically just above the hairline and it takes up an estimated one-third of the brain. It's clearly something that is laid down genetically because when babies are born, when indeed all mammals are born, they have a region of the brain that if nothing weird happens, if they just develop as they should, that region handles input from the eyes. But just as you said, in some people either because of brain damage or retinal damage, they are blind either from birth or from a very, very early age and I am emphasiz[ing]
e on early age because although neuroplasticity is possible throughout the lifespan, there is no question that it gets less strong as we get on in years. So, the experiments have shown that in someone who is congenitally blind or who lost his or her vision in early childhood, its like the visual cortex is sitting there waiting for signals to come, but they are not coming; either because they are stopped right at the eyes or at a way station in the brain, but for whatever reason, signals from the eye are not reaching the visual cortex. Well, you know, not to belabor the analogy, but its like, you know, a lighthouse keeper waiting for the great ships to pass by and now we are in the age of aviation, and there is nothing to do. So, the lighthouse keeper gets a new job. He gets retrained, he gets you know, a new career and that's what the visual cortex does. The experiments have shown that in people who have lost their vision at an early age, the visual cortex can for instance process sound and that seems to underlie why people who are blind are really, really good at auditory processing. They can pick up sounds that you and I can never perceive and then the visual cortex can also in some people begin processing sensory, somatosensory feelings.
Nicholson: The Braille reading.
Begley: Exactly! So, this is the fingertip sensation, and again if you are blind and if you start to learn braille, it doesn't have to be that early, it can be an adolescence or young adulthood. Again the visual cortex was not getting anything from the eyes, but its suddenly getting a tsunami of input from the fingertips as people learn to read braille and it turns out the visual cortex now processes these sensory feelings. And there is a third one. There is so far,
have[has] been one sensory region, the visual cortex changing jobs to process a different sensation, but one of the basic five senses are there—hearing or feeling. In some people, the visual cortex—again it's not receiving any signals from the retina—starts to process language. It does things like semantics and grammar, which is just a completely different kind of function than basic sensory processing, but somehow again the visual cortex was not doing what genetics or nature wired it up to do, but instead its getting a lot of linguistic input, so its starting to parse the meanings of words and of sentences. So again the bottom line seems to be that the brain is wired for all sorts of things that we normally don't have. But if the circumstances are right, if unusual demands are placed on the brain, then it can, you know, rise to the challenge, and you know, sort of meet that challenge.
Nicholson: Another incredible challenge rising—speaking of rising to meet a challenge—is that in stroke patients and Edward Taub’s research, and that's a different sort of thing in the sense that he constrained, that you can go ahead and mix them (laughs), but that was amazing in terms of giving someone a challenge.
Begley: Well, it was and it was one of the first manifestations of how neuroplasticity could be tapped to help people. Taub had been doing a great deal of research on primates and he got into a great deal of trouble for it. But he went on, he rehabilitated himself and he began to wonder if the damaged region in someone who has suffered a stroke, that's not coming back, but what if a different part of the brain could sort of pitch in for that damaged region. So in a not a typical stroke, lets say, the region in your right motor cortex that controls your left arm has been damaged and the immediate result of course is that your left arm is paralyzed; it hangs uselessly at your side. Taub had the idea instead of helping stroke patients get through their days by doing everything with their right hand, which many people have learned to do, I mean, rehabilitation has done wonders for stroke patients, but not all of them, but he thought "Well, lets do something that's completely counter-intuitive’. Let's restrain that good arm, in this case, the right arm." He has people just put it in a, you know, little sling and wearing [an] oven mitt
en on their hands so that they are not tempted to use that right arm or that right hand. And he and his team, it's the most laborious thing you’ve ever seen. You sit there and watch these people and it takes half an hour just for them to reach out for instance and pick up a peg to put it in a hole, which is one of the therapies that they are doing. And they do it for typically 8 hours a day—it's a full-time job, 5 days a week for a couple of months at least, whereas typical rehab is a couple, of three hours a day, may be two or three times a week. So Taub immediately realized that if you are going to change the brain, it really does have to be a full-time job. Anyway to cut to the bottom line, what he found is not only do people whose left or right arm, whose left or right leg have been paralyzed by stroke, not only can they regain that function, but what was so fascinating was how they regained that function. So, what he did was you know just standard brain imaging to see which regions of the brain are active when they were moving—let's keep to the example of moving their left arm. Again, in most people who are wired the way most of us are, the brain region that controls that, is the right motor cortex; again, in this example, that region was knocked out by a stroke. It turns out that the region on the mirror image side, in this case the left motor cortex, has suddenly started moving the left arm. The left motor cortex used to move the right arm, it still does, but now it has taken on a second job or in some patients, because its not uniform, a region just forward of the damaged region in the right motor cortex called the premotor cortex has started to be essentially the primary motor cortex and moved that left arm. So here is a striking example, getting back to your very first question of how a region of the brain that had been zoned for one thing, again either moving the other side of the body or sort of preparing the primary motor cortex to move, had taken on a whole new function because new demands were placed on it. So when we talk about neuroplasticity, changing brain structure and function, that really is a striking example because, again, if you look on your, well, you know, pretty little brain diagram, this little region was labeled, move left arm, and this region was labeled, move right arm, but instead the move right arm region is now moving the left arm also.
Nicholson: Yeah, now it's amazing. And one of the other interesting things in terms of looking at the dogma and how long it lasted for; and what's kind of continued more recently—a leap forward into kind of more genetic determinism in that the genes dictate who we are and that we have limited capacity for change, specifically they do with free will. And the research that you said in your book, really brings back this idea that we do have a capacity of free will, so when Taub's patients are actually forced to use their damaged arm, you won't say damage[d] arm, but damaged area of the brain that functions with the arm, that's one thing, but for those that aren't even physically restrained but use their mental ability to change their brain—that actually by thinking—and I was thinking of the example of, well it's a musical example actually. Maybe you could talk about that.
Begley: The virtual piano players?
Nicholson: Yeah! The virtual piano players, I mean this is an example of that just by mere thinking.
Nicholson: You are actually affecting ...
Begley: This sort of sequence of research in neuroplasticity has been—first they established that the adult brain can change through things like Taub's work where the sensory input was different or actually in patients who are blind, where they are getting greater sensation arriving at the brain from their fingertips. So once they've laid that foundation that the brain has the capacity for change, then the obvious question is, well what can change it? So yes different sensory input can change it, but how about input not from the outside world but from within the skull. So the experiment you are referring to had a bunch of volunteers come into a lab at one of the Harvard Medical School Hospitals and half of them would sit in front of a piano keyboard five days a week for several hours a day and play a little, actually just one handed, a five-finger little piano exercise and another group of people would sit at the keyboard, but rather than actually having their fingers touch the keys, they would just look at the musical notation and think about it. So after five days what did the scientists find? Well, you can comparably guess the punch line: Even in the so-called virtual piano players—those whose fingers had not touched a single key, but who had just thought about it—the region of the brain that controls the right fingers had expanded just as much as in the brains of the people who had physically and literally been you know, had their fingers dancing along the keyboard for a week. So that was a very striking example of how thinking, how just something happening inside the brain itself with no input from the outside world can change the physical structure of the brain. And I keep saying physical structure, because to me if a region that had originally been zoned for one function is now performing a different function
and[then] certainly you know you are not getting new neural tissue here. The brain has to make do with what it has. So if the area that controls the right hand's fingers had gotten bigger. Well it had encroached on some other territories that would have taken on a new function; that to me is a change in the structure and function of the brain and that has now been the basis for asking, "Well, what other thoughts can change the brain and in what way?"
Nicholson: Right, presumably, you know, athletes, I think, have known this for sometime in terms of Olympic skiers. I remember, they would stand at the top of the hill before they race and actually close their eyes and sway their body, imagining going down the hill in a certain way—and anyone whose been kind of coached in those kinds of talents has it—visualize yourself going through the exam; imagine yourself going through the ski hill, but maybe science has to catch up with what you've seen in your life or what.
Begley: Well, I think that's a good example, but there is no question anymore that mental practice has physical consequences. Another example is practicing a diving turn or forehand in tennis, anything where there is a sequence of motions, moving different parts of the body in a highly choreographed sequence; and there it turns out that just as with the piano players, as you think, "’Okay, you know, lift right hand, step back, move shoulders this way"; whatever the sequence happens to be, the thought of doing that is strengthening the synaps[se]
is, probably on the motor cortex as well as in the premotor cortex. So that when you initiate that sequence in real life, the right subsequent circuits or neurons are more likely to fire efficiently, to fire quickly with results in your doing, you know—you are executing a terrific forehand or perfect diving turn or, you know, getting, really nailing, that slam course. So yes, I mean, just as you are saying that athletes and coaches had intuited or found through experience that this works, now we have a firm, you know, neuroscientific basis for recognizing it
Nicholson: And not only thinking through physical motion, but then moving into some of the research that you talked about, depression and obsessive-compulsive disorder—OCD.
Begley: Well, that's exactly the sequence that the research has taken. Again establishing a sensory input can change the brain. Then establish[ing] that thinking can change the motor cortex, in which regions of the brain handle movement. Then the question is, well, what else can thinking do? So one of the earliest experiments on this, was, as you say, with patients who suffer from obsessive compulsive disorder; and this worked because it was pretty clear exactly what region of the brain had gone wrong to cause this illness; and it's a region centered, it's a buried surface in the center of the brain, centered on a little circuit called the anterior cingulate, and it basically just is over firing, it's overactive. And it's called the worry circuit, because in people with OCD, one of the symptoms is just chronically worrying that they left the stove on or they left the front door unlocked or that the door knob is covered with, you know, pathogens. So because the scientists knew what region was overactive, they had some idea of what they should be targeting. And this researcher at U.C.L.A.—his name is Jeffrey Schwartz—who had been himself a practitioner of Buddhism and in particular a form of meditation called, mindfulness, got the idea of training patients to think about their thoughts. So when the idea that something is wrong, again a typical OCD thought arose, he taught them two things. One, realize it's not real: It's not really the case that the stove is on; it's not really the case that your front door is unlocked; it's just a brain glitch, just an errand signal from a region that is overactive for no good reason. And then he taught them—over-simplifying here but—think about something else; redirect your thoughts to a more productive, a more therapeutic activity, I mean, just like gardening. We are not talking about, you know, doing your (unclear 20:58) or anything but just something diverting, but something that requires at least some of your attention. Anyway again the bottom line is, when patients learn to do this—it's a four-step process—the region of the worry circuit became much less overactive. It showed normal activity and not surprisingly their symptoms were much, much less frequent; they were less strong. And these people were able to get on with their lives as they had not been before. So
they only have [here is] a case of [how] just thinking in a certain way had altered activity in a crucial brain circuit.
Nicholson: What are your predictions for the next 10 years in terms of brain research if you dare, I dare ask you?
Begley: Sure. I think that we have seen only the opening wedge of what neuroplasticity can do. And the reason I say that is that if you look at the problems or the just general subjects where we have seen that the brain can change, it has followed a fairly predictable course. In the first step, you identify what's wrong in the brain. In the case of a stroke, you say, the lesion is here. In the case of OCD, you say, the overactivity is in this circuit. In the case of dyslexia—which is another illness where neuroplasticity has been engaged—it's an inability to process very staccato auditory sounds. So again what has gone wrong in the brain? The second question is okay, what input or the,—literally—input in other words from the outside world can change it, or input just generated internally can change it? And again, just as with the stroke work, it was figured out that if you force the bad arm or the bad leg to move even though the patient doesn't think it can; if in the case of OCD, you direct the patient's thoughts to something else, if in [a] case of dyslexia, you pipe into the ears certain kind of drawn out speech—those inputs alter the region of the brain, the circuit that had gone wrong. So then you start to ask, "Well,what are some of the other brain diseases where we know sort of what's gone wrong", and you start looking at schizophrenia and autism and even multiple sclerosis people are talking about, aging, Alzheimer's and Parkinson's. You know, Christie if you ask me bet a nickel, I would say that schizophrenia is more likely to be amenable first to input or to neuroplasticity; Alzheimer's where you have actual whole-cell death of synapses and neurons, just feels like it will be much harder. You know on the other hand, a particular region of the brain is damaged in Alzheimer's, so could you train a different region to take over the damaged part? Who knows? I think if we've learnt anything from the last, really just five years of neuroscience, it's that we have in the past solved the brain shore, we have dismissed the possibilities as impossible; and if the neuroplasticity revolution has taught us anything, it's that we should be more open minded about how the brain can change and what it can do and our ability to figure out how to elicit those changes.
Nicholson: Sharon, thank you so much for spending time with us today; we really enjoyed it.
Begley: Thank you, Christie, it was great.
Steve: Sharon Begley's book again is called Train Your Mind, Change Your Brain. Begley is also the author of the cover story on the August 13th issue of Newsweek about the global warming denial machine; and you can also check out the article in the August issue of Scientific American titled, "The Physical Science Behind Climate Change". We'll be right back.
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Steve: Now it's time to play TOTALL.......Y BOGUS. Here are four science stories; only three are true, see if you know which story is TOTALL.......Y BOGUS.
Story number 1: A test of preschoolers found that they've been so influenced by advertising, that they overwhelmingly prefer the exact same food put in McDonald's packaging versus in unbranded packaging.
Story number 2: Researchers in Kenya have encouraging results in a study of an unusual weapon against malaria: Tilapia fish.
Story number 3: Researchers are developing a flashlight that could be shined into somebody's eyes to nauseate them.
And Story number 4: In other invention news, a company is creating a parking meter that sends out a limited field electromagnetic poles to deaden your car battery, should you let the time expire. Cops would then collect fines on the spot in return for a boost.
Time is up.
Story number 1 is true. Preschoolers preferred food in McDonald’s packaging versus the exact same food in unbranded packaging, even if the food was carrots. For more, check out the August 7th episode of the daily Scientific American podcast, 60-Second Science.
Story number 2 is true. Tilapia fish might make a good antimalarial weapon, because they like to eat the mosquitoes that spread the disease. In tests in western Kenya, the introduction of the fish caused the local mosquito population to plummet by 94 percent and local people can also feed on the fish that fed on the mosquitoes, which is much better than having the malaria mosquitoes feed on them.
And Story number 3 is true. Researchers are trying to make a flashlight that would enable police to disorient or nauseate somebody they are trying to catch. The flashlight pulses very bright light and if that hits your eyes, you get nauseous or possibly vertigo. It's not entirely understood why that works, but perhaps future cops will yell, "Stop or I'll shine".
All of which means that Story number 4 about the battery-deadening parking meter is TOTALL.......Y BOGUS. But what is true is that Vancouver-based Photo Violation Technology Corporation is currently testing a smart parking meter in Vancouver and Niagara Falls, New York. The meter can tell you that your time is expiring by giving you a phone call and it will also accept additional payment by phone. The meter also provides an Internet hot spot; you can surf while parked, but be careful about violating your time. The meter will photograph your license plate and rat you out to the authorities.
Well that's it for this edition of the weekly Scientific American podcast. You can write to us at email@example.com, check out news articles at our Web site, www.sciam.com and the daily SciAm podcast, 60-Second Science is at the Web site and at iTunes. For Science Talk, the weekly podcast of Scientific American, I am Steve Mirsky. Thanks for clicking on us.