Andres Lozano: Can Hacking The Brain Make You Healthier? Neurosurgeon Andres Lozano talks about dramatic findings in deep brain stimulation.

Can Hacking The Brain Make You Healthier?

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A long time before Andres Lozano became a renowned brain hacker, he was actually fascinated by how the brain works. And he remembers the moment that fascination began.

ANDRES LOZANO: When I was a teenager, I watched a television program about Dr. Penfield.


WILDER PENFIELD: This is the brain.

LOZANO: Dr. Penfield was a famous Canadian neurosurgeon and he did epilepsy surgery with the patients awake.


PENFIELD: Now when we stimulate at...

LOZANO: And he was able to stimulate the surface of the brain and, in so doing, elicit actions, elicit thoughts, elicit movements, elicit vision.


PENFIELD: We stimulate it. And to my astonishment, you said, I hear music. If you hum it now, you'll remember it.


PENFIELD: Go ahead.


LOZANO: While Penfield mapped the surface of the brain, the majority of the brain, of course, is below the surface. And so I was interested in establishing what these uncharted areas of the brain do. So it's really like becoming an explorer or traveling to new lands where no one has been before and to discover what lies there.

RAZ: So fast-forward decades later, from curious teenager to renowned neurosurgeon. And the day Andres Lozano gave a jaw-dropping TED Talk on how he's hacking into the human brain.


LOZANO: So there are areas of the brain that are dedicated to controlling your movement or your vision or your memory or your appetite and so on. And when things work well, then the nervous system works well and everything functions. But once in a while, things don't go so well and there's trouble in these circuits. And there are some rogue neurons that are misfiring and causing trouble. Now the manifestation of this depends on where in the brain these neurons are.

So when these neurons are in the motor circuit, you get dysfunction in the movement system and you get things like Parkinson's disease. When the malfunction is in a circuit that regulates your mood, you get things like depression, and when it is in a circuit that controls your memory and cognitive function, then you get things like Alzheimer's disease. So what we've been able to do is to pinpoint where these disturbances are in the brain, and we've been able to intervene within these circuits in the brain to either turn them up or turn them down. So this is very much like...

RAZ: How does it work?

LOZANO: Well, we are able to adjust the activity of circuits in the brain by using electricity.


LOZANO: So what we're doing is placing these electrodes throughout the brain. We are making holes in the skull about the size of a dime, putting an electrode in and then this electrode is completely underneath the skin down to a pacemaker in the chest.

So we are able to go into various circuits, for example, a circuit that controls movement, a circuit that controls your mood.


LOZANO: And with a remote control, very much like a television remote control, we can adjust how much electricity we deliver to these areas of the brain.

We're able to either turn it up if it's underactive, if it's underperforming, or we can turn it down if it's overactive. So this is very much like choosing the correct station on the radio dial. Once you choose the right station, whether it be jazz or opera - in our case, whether it be movement or mood, we can put the dial there. And then we can use a second button to adjust the volume.

So using electrical stimulation, we can influence the activity of neurons anywhere in the brain.


LOZANO: Now the first example I'm going to show you is a patient with Parkinson's disease. And this lady has Parkinson's disease and she has these electrodes in her brain. And I'm going to show you what she's like when the electrodes are turned off and she has her Parkinson's symptoms, and then we're going to turn it on.

RAZ: In your TED Talk, you show this incredible video.


LOZANO: So this looks something like this.

RAZ: This woman with Parkinson's, she's shaking.


LOZANO: And you can see that she has tremor.


RAZ: All of the sudden, the deep brain stimulation is turned on.


LOZANO: It's on.


LOZANO: I just turned it on.

RAZ: And she stops.


LOZANO: And this works like that. Instantly.


RAZ: How - what's going on?

LOZANO: What is going on is that there are a bunch of neurons that are troublemakers that are causing the tremor. And so, if we're able to pinpoint these neurons where they are - these troublemakers, and say, you know, gentlemen, that's enough. Then the tremor goes away immediately. And sure enough, when we place an electrode in the vicinity of these neurons and we apply electrical stimulation, they can no longer fire in synchrony, and the tremor goes away immediately.

RAZ: So there are Parkinson's patients around the world who have this implant in their brain whose symptoms are totally controlled?

LOZANO: Indeed. There are a hundred thousand patients in the world with Parkinson's disease that have these deep brain stimulating electrodes and their symptoms can be alleviated to a great extent, such that some of these patients look perfectly normal.


LOZANO: We realize that perhaps we could use this technology, not only in circuits that control your movement, but also circuits that control other things. And the next thing we took on was circuits that control your mood. And we decided to take on depression. And the reason we took on depression is because it is so prevalent and, as you know, there are many treatments for depression with medications or psychotherapy, even electroconvulsive therapy.

But there are millions of people and there are still 10 or 20 percent of patients with depression that do not respond, and it is these patients that we want to help. And let's see if we can use this technique to help these patients with depression. So the first thing we did was we compared, what's different in the brain of someone with depression and someone who's normal? And what we did was PET scans to look at the blood flow of the brain and what we noticed is that in patients with depression, compared to normals, areas of the brain are shut down. Those are the areas involved in motivation and drive and decision-making, and indeed, if you're severely depressed, as these patients were, those are impaired. You lack motivation and drive. The other thing we discovered was an area that was overactive - area 25. And area 25 is the sadness center of the brain.

If I make any of you sad, for example, if I make you remember the last time you saw your parent before they died or a friend before they died, this area of the brain lights up. It is the sadness center of the brain. And so patients with depression have hyperactivity, the area of the brain for sadness is on red-hot. The thermostat is set at a hundred degrees. And the other areas of the brain involved in drive and motivation are shutdown.

So on the basis of those observations, we embarked on a study to implant electrodes in area 25 and turn on the electricity to see whether we could turn down the activity in this area to see whether this would have some benefit in people with so-called treatment resistant depression.

RAZ: What did you see, Andres? I mean, with the patients, did they all of a sudden become happy?

LOZANO: So many of the patients will say that they have this black cloud over them or they have this tremendous weight - this pressure on their chest. And within - turning this on, within two or three seconds, that sensation disappears in about two-thirds of the patients.

RAZ: Two to three seconds?

LOZANO: Yeah, it takes two to three seconds. They say, this burden is lifting. I feel a tremendous relief. And then they start looking around, then they start becoming more engaged. These are people who often do not leave the house, who sit in a chair all day, and all of a sudden, they'll say, I feel like doing some housekeeping. Or a man will say I feel like going into my garage and, you know, fixing the car. A tremendous sort of call to action to do things that they were not able to do for many weeks and months. And all of this occurs within 10 or 15 seconds of turning on the stimulator.

RAZ: You must - on a regular basis - conduct these experiments and come home at night and just think, that was amazing, that was incredible, what I just witnessed.

LOZANO: What is incredible is when we go to an area of the brain where no one has been before, and we don't really have a good understanding of what it does, and we stimulate there and all of a sudden, we get a totally unexpected finding. A good example of that was when we were treating a patient with obesity by implanting electrodes in the area of the brain that regulates appetite. So when we were doing this experiment on the first human being who had this, as soon as we turned on the stimulator, he told us that he felt he was 30 years younger and was walking through a field with his girlfriend.

So we were not anticipating that. As soon as we turned off the stimulation, this memory went away. As soon as we went back at the same level, we were able to re-create this memory. And as we turned up the current, the details of this scene became more vivid. And so he was able to tell us, it was a sunny day, he was able to tell us, his girlfriend - what she was wearing. We were completely turned around towards looking at an area of the brain where we could unlock a memory of an event that had occurred some 30 years earlier.

RAZ: It's like science fiction.

LOZANO: It's cartography. It's mapping an unexplored galaxy, an unexplored universe.

RAZ: I mean, the possibilities must be endless. I mean, you could imagine this technology, I don't know, being used to make people smarter.

LOZANO: If you ask me is that theoretically possible, the answer is yes.

RAZ: Wow.

LOZANO: Should we do it? That is something that has, you know, a different action. But the idea of altering cognitive abilities, altering personality, is within our reach now. This will then usher what is being called as the era of cosmetic brain surgery, where you will have the possibility of having neurosurgical procedures, not to cure a problem, but rather to enhance the performance of a particular cognitive attribute or behavioral attribute. So I don't think that we are ready for that. I think society is not ready for that now.

RAZ: But, I mean, what's wrong with it? I mean, what if someone wanted to become smarter?

LOZANO: Well, there's issues of, you know, distributive justice in terms of who will get this, who will pay for it, for example. Should we be messing with your intrinsic makeup - your intrinsic personality, for one thing? And secondly, who should be making the decisions as to whether you should have this or not? So these are some of the points that need to be considered.


LOZANO: So I envisioned that we're going to see a great expansion of indications of this technique. We're going to see electrodes being placed for many disorders in the brain. And I think that we will see that, indeed, we will be able to chase more of these evil spirits out from the brain as time goes on. And the consequence of that, of course, will be that we will be able to help many more patients.


RAZ: Andres Lozano is a neurosurgeon at the University of Toronto. You can find his full incredible talk at


KASABIAN: (singing) Hit me! Harder! I'm getting re-wired. I flip the switch that make you feel electric. Even! Faster! Than before. I'm gonna light 'em up with you. I'm gonna light 'em up with you.

RAZ: Hey, thanks for listening to the show this week. If you missed any of it or you want to hear more, you want to find out more about who was on it - you can visit You can also find many, many more TED Talks at And you can download this program through iTunes or the NPR smartphone app. Look for the TED Radio Hour.

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