For more than three decades, Dr. Michael Merzenich has been a leading pioneer in brain plasticity research. In addition to teaching and doing research at the University of California, San Francisco, he is a member of the National Academy of Sciences and the recipient of numerous awards and prizes. Dr. Merzenich’s work has been covered in the New York Times, the Wall Street Journal, Time and Newsweek. He has appeared on Sixty Minutes II, CBS Evening News and Good Morning America. He earned his BS degree at the University of Portland and his Ph.D. at Johns Hopkins.
What’s the most exciting thing you’re working on these days?
I’ve been working with psychiatrists from Yale and UCSF on intensive training for individuals who have developed schizophrenia. I can’t tell you exactly what we’re doing, but we’re trying to drive the brain in a corrective direction.
We’ve trained quite a few active schizophrenics, and we have had big effects on them. The question is, can we prevent this illness from happening in the first place, or change the probability that a young person will collapse into it if they have an inherited weakness for this condition. I’m excited because I think to use the brain’s natural resources to help fix itself so that it basically doesn’t suffer a catastrophe like this would be just a fabulous thing.
The other thing I’m having lots of fun with has to do with the brain and predictions. It’s a little bit hard to explain, but let me try. If you hear something or see something that’s familiar, you immediately make associations to other things that relate to it. You predict what should happen next.
A simple example would be that after just a few notes, you know that you are listening to "Twinkle, twinkle, little star." Your brain is making a forward prediction, which it continually does each moment in time. You can think of these predictions as being the motor that drives our stream of consciousness. As you listen to someone talk, you’re continuously making predictions about the little pieces of successive sound. And the completeness and accuracy of what you hear largely comes from those predictions.
We know that in many human maladies, this machinery is broken. It’s catastrophically broken in a psychotic patient, who can’t control predictions at all. We’ve been studying these processes in rats, and we can now see how it works. And we can also see how to improve it.
I’m really excited about this because I think it is an aspect of dysfunction in the brain that nobody has fully appreciated. And when we apply our knowledge, I think we’re going to have a powerful impact.
What types of applications do you think we can look forward to seeing in the future?
We’re going to get better and better at dealing with cognitive loss and motor loss, both of which come from the normal process of aging. You know, if you live long enough, Alzheimer’s becomes almost a certainty. If you live to be 85, there’s more than a 50% chance you’ll be cognitively impaired and not be able to take care of yourself. We’ve got to change this picture.
What we’re trying to do is strengthen brains enough so that their functionality can be sustained longer and longer, so more people can live to the end of their lives with good control of their cognitive abilities. I think we’re going to get better and better at training brains in ways that have prophylactic benefits.
Another thing we’ve been working on is dealing with cognitive losses that occur as a product of the vicissitudes of life. There are about 5 million Americans a year who have a direct trauma to the brain. There’s another million a year that undergo high levels of chemotherapy or radiation. One in five of those people will be cognitively or neurologically impaired for the rest of their days. Another related problem is brain infections, the common source of which is AIDS, but can also come from Lyme disease and West Nile virus. People don’t realize that these infections can lead to long-term impairment.
Again, we’re having very positive results with this population by training their brains to get more out of them. We’re doing it by using adult versions of Fast ForWord exercises. But we’ve also extended the exercises to include vision training and other areas Fast ForWord doesn’t address.
Let’s switch for a moment to an average person who lives in the modern world and has to assimilate an incredible amount of information. Do you think the average adult can benefit from retraining the brain? And is this something we should all be thinking about doing?
Absolutely. I think that no child or adult is getting the most out of their brain. That’s because we focus on content acquisition. We read a lot, we’re active in listening. And our knowledge base grows throughout our lifetime. In that respect, the average 70-year-old is advantaged over the average 20-year-old.
But when it comes to doing a job well, it’s a whole other story, because there’s more that contributes to performance than just knowledge. There’s the speed at which you can work on a problem and come to a solution. Content is a critical asset, but how fast your brain works is just as critical. That’s why we’re looking to improve the ability the brain has to take in and process information. It’s what Fast ForWord does for children, and it’s what we’re focused on doing for older individuals. You can improve a brain at any age. If you improve the speed and processing abilities of a 60-year-old, given the greater content of their brain, that person is going to run circles around your average 20-year-old.
Let’s talk about young children for a minute. Given what you have found out about how children’s brains develop, should we be educating our children differently from the way we’ve been doing it for centuries?
I think so. One of the things we’ve gotten into in our modern era is the notion that we have to teach every child to know the same things as every other child. In my opinion, that’s quite wrongheaded. It doesn’t reflect what makes a child effective in the real world. What you want to do is to set up the child to be as efficient as possible in acquiring new information regardless of the content domain. The rest takes care of itself.
Of course, every kid needs to know certain things as a member of society, in preparation for life and for being part of our culture. But beyond that, the most important thing is teaching the brain to learn how to learn. That enables every kid, no matter what their interest is, no matter what their profession eventually becomes, or what hobbies they develop, to make the most of it.
What’s being done these days in the rest of the world in the area of brain research and the application of neuroscience?
Some of the best things are being done in the Netherlands, Germany, Britain, Sweden, France and Spain. In all of these countries there are research groups trying to create brain science-based programs to benefit both normal and cognitively impaired populations. But 95% or more of that effort is directed toward drug development, although there’s an increasing interest in developing non-drug strategies.
Over the past couple of decades, there seems to have been an explosion in the number of children suffering from autism and other brain-based disorders. What are your thoughts on this?
The Centers for Disease Control believes that somewhere over the past 20 years there has been as much as a tenfold increase in the incidence of autism. It’s a massive societal problem. We’ve gone from a place where autism was a rare human condition to one where it now occurs in one out of 150 births.
It’s a complicated issue. Autism is actually a severe form of what used to be simple language impairment. We have studied this by creating animal models of autism, primarily in rats. We believe that the fundamental fault is a "noisier" than normal brain that forms early in life. This is a brain that is struggling to organize itself in the face of internal noisiness, you could say.
What can increase this noise? There are any number of factors in the environment, but my own opinion is that it is environmental toxins that are the issue. My primary suspects are PCBs and DBDEs, which are closely related organic molecules. DBDEs, commonly known as fire retardant chemicals, are doubling in the environment every two to five years.
We’ve raised young rats under conditions in which their brains are noisy. When you add PCBs on the level in which it’s been recorded in human breast milk, it has devastating effects on the brains of these rats. I’m not saying we know for sure that this is true in humans, but it is suspect.
Another possible source of autism is the noisy environments in which infants are being reared these days. Today we raise babies in the den. There’s a television playing in most houses for many hours every day. A lot of people put their babies in front of the TV in the first year of life. That’s a lot of visual and auditory noise for an infant.
None of this bodes well for the future.
It doesn’t. But we do learn. If we are, in fact, poisoning our environment, it will be a great lesson to us. It will make the asbestos scare look like small potatoes. Imagine if we find out that fire retardant chemicals are really a root cause of the increase in autism. Think of how hard it’s going to be to get rid of them. They’re everywhere. In every appliance, every computer console, the telephone you’re holding to your ear.
In spite of this, do you feel optimistic about the future?
When you’re older, there’s a tendency to be a little bit pessimistic. You wonder if the human race is smart enough to deal with these problems before they do us in. I think we need to be slapped around a few times. Actually, we have been, but have we learned from it? I wouldn’t bet the farm on that. But I’m very optimistic about translational neuroscience doing more and more good in the world. And really, that’s all I can control.