An interview with neurologist Prof. David Presti

TRP: What are your comments on the current state of brain science?

DP: Well, brain science is a very exciting frontier. Everyone makes the connection between our brains and our behavior and we believe that our brain has a lot to do with our behavior.  The evidence for that is pretty direct; that is, if you damage the brain you get profound changes in behavior that don't happen if you damage other parts of the body. So we put it together that there is a relationship there. With the advances in technology that have happened in the last twenty years that have now been applied to brain science, it is possible to ask and get answers to very interesting questions that we never had ways to ask before. It's a combination of being interesting and being do-able. Outer space and trying to see whether there's life on other planets and exploring the large-scale structure of the universe is also very interesting and exciting but we can't do it. We don't have the technology available. But with the brain, there are profoundly interesting questions that can now be asked with imaging technologies, things like functional magnetic resonance imaging, PET scans, ways to actually see what's happening in a living human brain. So we might actually be able to get some information about what are the processes in the brain that correspond to mental states like awareness and changes in consciousness and these sorts of things.

Is the whole right brain/left brain dichotomy still considered valid or has it been pretty much shelved as another fad?

It's definitely considered valid. There's a way in which the whole left brain/right brain specialization got overly magnified by the popular press. But it's very clearly still true that the two halves of the brain do different things. There are a lot of similarities between what they do and there are profound differences. This can now be very clearly visualized with the functional imaging techniques. There are differences in the functioning in the hemispheres. The old description of the left hemisphere is that it is more language-oriented, logical, linear, mathematical, and that still holds up for some things. And the right hemisphere is more Gestalt, non-verbal, big-picture stuff — that's still accurate and these things will show up on functional imaging. The old EEGs (electroencephalographs) were too crude really to show the differences the way the new technology can.

You can localize, say, picking up objects, but what about mapping something like discoursing on economics or creating poetry? How will that ever be mapped?

It's a long way off. There is this tendency to build up a lot of information about what parts of the brain are doing what when, but it may not really be telling you that much. So at the same time you need to have cleverly designed experiments which will help address the really interesting questions. So we have on the one hand the building up of an increasingly large amount of knowledge and information about the brain, and although that may not answer the big questions, it will form a landscape upon which those questions can be asked and data that can be drawn from in the future.  As far as being able to talk about what's going on in the brain when we philosophize or discourse about economics or create poetry — that's a long way off. However, I think it's within the realm of what we will be able to ask within the next few years with these new technologies. We still have no real operational definition of what states of consciousness really are or mental states or thoughts with particular content or emotions. We believe that this is all related to nerve cell activity in the brain in certain circuits going on and certain neural transmitters being released. We don't know how that is actually related to subjective experiences. That's really the biggest gap which is of interest in addressing scientifically. We're building up more and more knowledge of neural transmitters and receptors and how different chemicals affect them. But how this actually ties in to the kinds of states of brain functions that we experience as thoughts and emotions and particular creative acts like poetry, we have no ideas at this point.

Still "forbiddingly alien".

Yeah. Although not beyond the realm of being able to ask questions. A few years ago we had no idea how to do this. But now we are getting a better sense about how to ask the big picture questions.

Have you heard about E.O. Wilson's idea of  "Mind Script"? That you could create a language from mental imaging just by viewing brain function while it's doing something and then taking those coordinates and condensing them in something like different Chinese ideograms?

If we were able to map brain activity carefully enough and then produce some way of stimulating that activity, that's not too far out. In a crude way that's already done. For example, we know that the rear part of the brain is involved in vision and analyzing information that comes into our eyes, to give us the experience of the visual world. So when we see stuff there's all kinds of complicated electrical activity going on all over our brains but especially in the posterior part. If we take a magnetic stimulating device, which is basically just a little magnetic coil, and put it above the back of the brain outside the skull, just set it there next to the head, and give it a jolt of electricity to produce a magnetic field that then goes through the skull and electrically zaps the neurons in there so they start firing, you can actually generate visual images in people. But it's rather random; we don't know how to produce a carefully designed enough outside electromagnetic stimulus to produce some predictable response in a person's visual experience, but you can get them to see flashes of light and hallucinatory stuff like that. Or if you stimulate the front part of the brain that controls movement, you can get jerking of the arms and stuff like that. So in a crude way we can stimulate the brain from the outside and get people to experience things. And as we get more and more refined in our ability to map brain function and then create stimulating devices to stimulate it we may be able to do stuff like that.

It's also now possible to implant electrical stimulating devices in the brain. The one place this is done so far is in the treatment of Parkinson's disease. Parkinson's disease is a movement disorder due to a loss of particular neurons from cell death, probably as a result of exposure from toxins of various sorts that we are all exposed to. Patients lose the ability to initiate movements and they suffer from severe tremors and so forth. This affects a large number of people, especially elderly people. A stimulating electrode can be implanted in a particular part of the brain called the motor thalamus, and actually overcome some of the problems that Parkinsonian patients have. When they experience their symptoms in a severe way they have a little switch they can turn on, which is imbedded in their shoulder, and they can use a magnet to run over the switch and turn it on.

Is that happening now?

Yes. These surgeries are being done quite frequently and they work. If you can implant an electrode in that part of the brain and stimulate it, in principal you can implant an electrode anywhere in the brain and stimulate it. You can imagine having an electrode implanted in the circuitry that controls mood in some way, so that when you stimulated these circuits you would feel better. That's theoretically possible. We think we know enough about some of this circuitry now to make some guesses as to where they are.

Do you think these circuitry boxes are the wave of the future for teeny-boppers? Something fun to do at parties?

I don't. It's much too complex an enterprise. We're talking big-time brain surgery here to implant these things. This is not something you do on the weekend. But on the other hand these external stimulating devices, if they could ever be refined and perfected enough to actually target particular areas of the brain, it's conceivable that might lead to some sort of external stimulation.

A lot of people think that would be the summum bonum of advertising: You could beam a desire into someone's brain... like if the Gap could get a control tower and zap people...

Yeah, with a trans-cortical stimulating device. But I don't think the Gap's going to be able to do this. To actually be able to stimulate a particular pathway so specifically as to generate the thought of a particular product — I don't rule anything out as being possible at some point in the future, but that is so inconceivable...

Is it really? It seems like television is the device influencing the most brains.

It is being done through the media. It's absolutely being done through television, radio, other sorts of advertising. But it's not being done directly to the neural circuitry.

It seems like a lot of neuroscience just views the human body and brain as a brute machine.

That certainly is the stance of most science and most biological science, that the organism is treated more or less like a machine. A definable or knowable mechanical structure, at the atomic or molecular level. And behaviors are related to the operations of chemicals and physical processes going on at the molecular level at a machine-like way. The human brain is by far the most complex structure we know of in the universe: a hundred billion or more nerve cells, each of which is connected to hundreds or thousands of other nerve cells. It's phenomenally complex. But the underlying guiding hypothesis, so to speak, is that as we learn more and more about the brain, we will somehow be able to intervene in the processes in some way, as I've already described in the treatment of Parkinson's disease for example.

What do you think the future of Prozac is? It has swept the Western world in a revolutionary way.

It is a revolution. The new generation anti-depressant medications, of which Prozac was the first to come on the market, are very profoundly affecting our conception of the brain and our understanding of brain chemistry. It truly is a revolution. I like to point to various things that I think were revolutionary in the history of brain chemistry, and I think Prozac and the other medications in its class are the most recent example of that. It has made neural chemistry something more than just the esoterica of brain science. It's now cocktail party discussion. Into the popular press. Into the daily newspaper. You can now open up a newspaper and see pictures of neurons releasing serotonin. It's now clear that small amounts of chemicals can have a profound impact on the function of the brain and through that, the behavior of people. Now, what that means for society is very interesting and I think we have an experiment in progress here. Millions of people are taking these medications for long periods of time. Originally they were intended for severe depression. But it has become apparent that they seem to help the functioning of people who aren't clinically depressed. Many people respond very positively to the things they feel they're getting from these drugs. There don't seem to be severe toxic effects that have come out in any way at this point. We don't know what the future will hold. This is an experiment in progress. We don't know what the implications are of taking something for ten, twenty, thirty years, perturbing the body chemistry for that long. Maybe nothing, maybe something.

There must be something. There are occasional violent outbreaks with people on Prozac.

I question that - at least according to the statistical analysis that I've read. There are so many people taking the medications that there will be a base rate that will commit violence or suicide. My reading of the literature is that there is no higher frequency in violence or suicide. But in fact, what happens is the media often focuses on that, when something does happen. For example, there's an article that I often use in class about a guy who three or four years ago tried to set off a bomb in the New York subway. He had a bomb on him, and he got busted. It said in the news article that he was taking Prozac. They said it twice, at the beginning of the article and at the end of the article. So people read that and they see it twice. The first thing they see in the article and the last thing they see in the article. But down the page, same paper, same day, there was another article about a police officer who committed suicide. It didn't say he wasn't on Prozac in that article, he probably wasn't, otherwise they would have mentioned it. The point is, these things happen all the time, and it's never pointed out when folks aren't on Prozac, but it's always or frequently pointed out when they are. So there is a perception that these kinds of things happen more often.

It's true, it does seem to get sensationalized. But I find it hard to believe that there's no correlation at all. For instance, one of the assassins at Columbine was on Luvox. I'm not saying Luvox was the reason it happened but that it must have been a factor, because those medications are involved in directly affecting the perception and emotional states of the brain. The drug is manipulating the brain's chemistry in uncertain, yet significant ways.

But I think it's important to point out that without very careful analysis, in a controlled way, of who is taking what and who is committing what kinds of behaviors, you can't make statements that Luvox had anything to do with this guy's behavior. The guy was pretty screwed up before he started taking these medications.

What about the controversy of MDMA toxicity and the brain?

Whenever we impose chemicals into the normal balance of the complex chemistry of our brain, there is a potential for adverse things to happen. And MDMA is an example, at least based on animal studies, that can have toxic effects on serotonin nerve cells, in that it causes a deterioration of the nerve terminals, some of which regrow with time and some of which don't seem to, according to limited studies in monkeys and rats. We don't know what the implications are for people. It also, of course, has a history of being a very useful drug in psychotherapy and so forth. So it's unfortunate that it may have these effects on serotonin brain chemistry too. But I think more research is needed, and some degree of caution is needed. I find it disturbing that there are people out there who take multiple doses of MDMA week after week after week, in the rave scene and so forth. We don't know what the implications of that are going to be. I hope there is a way to stay in contact with those folks and continue to study them over time, because, again, that's an experiment in progress. I think we need to be cautious about what the long term effects might be.

On a national night time radio show, called "Love Line," a doctor and a loud-mouth sidekick field questions from troubled people, mostly teens. A kid called up and wanted to know about LSD. The doctor wanted to dissuade him from using the drug and told him and all the listeners it was a "neurotoxin."

First of all, you have to find out what he meant by that. I can tell you what we know about LSD. There's no data that suggests that LSD has any direct lethal effect on brain cells. For a healthy person, there's evidence that suggests that LSD used appropriately does not cause any adverse consequences. At the same time, there are cases of small numbers of people that report long-term perceptual and emotional instability that may be associated with LSD use. Any time you have a problem with visual perception that doesn't go away, that suggests there has been some kind of long term or permanent change in the circuitry in some way. This has never been studied in any kind of detailed way. It's not even certain that it's due to LSD. But there does seem to be an association there. It's a relatively small number of people compared to the millions that have been exposed to it. But in the usual interpretation of what we mean by "neurotoxic", no, there's no evidence that LSD is neurotoxic. Up to this point, that is.

What do you think is the real basis behind the drug war?

It's complex. Part of it has to do with historical accident and the resulting economic enterprises that generate it. In this country, alcohol and tobacco are the historically accepted drugs. They were the ones that society decided to adopt way back when; in fact, this country was partly founded as a place to grow tobacco. Tobacco was discovered in the Americas and when the rest of the world became addicted to it, people discovered they could make a lot of money by growing it. So the original American colonies were partly there to farm tobacco for Europe. So tobacco and alcohol have been invested with the economic base to make them the drugs of choice. And everything else is competition. There's a real vested interest in keeping those drugs legal and available to generate profit, and everything else illegal.

There's also the issue that the entheogenic substances appear to be associated with changes in consciousness that generate new ways of looking at the world, and one's relationship with the world, and don't often propagate the status quo way of doing things. That's definitely what happened to marijuana and LSD associated substances back in the 1960s. They became very much linked with the anti-Vietnam war, anti-establishment mentality. That was perhaps the major reason they were banned from use and research. There was a huge research enterprise to try and figure out what the therapeutic uses of LSD might have been back in the 1950s and '60s. But that was all completely ended.

Do you see the tide slowly turning? Or do you think it will remain the iron fist the way it has been?

I don't think there's any turning. I think there are some small chinks of light that may be expanded upon in some way, such as the appreciation of the medicinal effects of marijuana and the opening up and softening of attitudes in the federal government around allowing research to occur with LSD, MDMA and other schedule one drugs. There is a limited amount of that research now going on and an openness to having more such research done, if people argue for well-designed studies. But I don't think that's a "turning of the tide". There's an opportunity here for good science to become possible again with these substances if it's done carefully.