To 'Keep Sharp' This Year, Keep Learning, Advises Neurosurgeon Sanjay Gupta

CNN's chief medical correspondent says it's never too late to develop new brain pathways. Even small changes, like switching up the hand you use to hold your fork, can help optimize brain health.

Transcript

TERRY GROSS, HOST:

This is FRESH AIR. I'm Terry Gross. My guest is CNN's chief medical correspondent, Dr. Sanjay Gupta. He's written a new book about the brain that explains some of the latest research, debunks myths about brain function and offers practical advice on improving cognitive function. It's called "Keep Sharp: Build A Better Brain At Any Age." Dr. Gupta has been a practicing neurosurgeon for about 20 years and is an associate professor of medicine at Emory University School of Medicine. He's performed brain surgery in war zones and disaster zones, including Iraq and Afghanistan. We're also going to talk about the coronavirus, which he's been covering for CNN. He got his first dose of the vaccine live on CNN in December.

Dr. Sanjay Gupta, welcome to FRESH AIR. This is a difficult time with the virus. You know, people - many people are working at home while schooling their children and doing more housework than ever before 'cause everybody's home. And the people who are working have to work in places where they don't necessarily feel safe. How do you think our brains are being affected by all of the stress of the virus?

SANJAY GUPTA: It's been really challenging. You know, I think that there is a thing about stress and the brain that has long been documented. And the headline is that stress is not necessarily the enemy. In fact, we need a certain amount of stress. That's what gets us out of bed in the morning, makes us perform well on tests, hopefully - all that sort of stuff. But it is that second adjective you used, unrelenting, that is really problematic here. We don't - we need these breaks from stress. You need that constant sort of ebb and flow. And that's what's missing.

Again, you don't want it to all be good all the time, but you need to have that sort of up and down to some extent. With things sort of the way that they are, we're sort of in this in this whiplash sort of time frame with regard to the brain. On one hand, things are getting worse. We see that the numbers continue to get worse over the last few months. And, you know, going into the spring, it's likely to continue that trajectory.

On the other hand, we also hear that there is a vaccine that is rolling out. It is happening. And that is going to be a significant impact in terms of bringing this pandemic to an end. So it's challenging for the brain right now, but it's important to constantly find times when you can either dramatically reduce your stress, either by thinking about the future with the vaccine and things like that or other things in your life. But I will say - and this really came out in the book, the idea of eliminating stress - I'm just going to eliminate my stress - It is not obtainable, nor is it necessarily a good idea for the brain.

GROSS: One of the things people are learning to do now is to live with new routines because you're working at home or teaching your children or getting to work in a different way, having to wear a mask. There's so many new routines that most of us have had to learn. Is that stressful on the brain having to, like, reorganize your life and not follow all the predictable patterns that you were used to?

GUPTA: I would argue that it's actually very good for your brain to find new patterns, new routines and to, you know, mix it up a little bit, shock the brain, shock the body a little bit - not in a bad way but just in terms of trying different things here. Here's the thinking - is that when you start to do procedural things over and over again, you can get very good at them. And that's important in a lot of jobs, including, you know, in the operating room, where I spend a lot of time. But I think for our brain, we want to constantly be using new paths and trails and roads within our brain. And that can be as simple as just doing something a little differently, eating with your left hand instead of your right hand if you're right-handed - you know, if you put a tie on in the morning like I do, sometimes, closing your eyes and doing it in the dark. The reason being you're just - the more you can recruit different parts of your brain to do even simple activities, the better it is for your brain now and the better it is for your long-term brain health.

GROSS: A lot of people are multitasking, trying to do two things at once. Are we fooling ourselves when we're multitasking?

GUPTA: I was surprised by this one. Even though I've been studying the brain for a long time, there was a lot that I learned. And the issues around multitasking were one of them. You know, the idea that you move from one task to another sounds great and very efficient. The issue was that they found you actually divert a fair amount of attention each time you do that. You may not notice it yourself, but when you start to objectively measure this with different types of brain scans, scans that are measuring the function of the brain or particular parts of the brain, at any given millisecond, you find that you actually expend quite a bit of energy just to switch from one task to another. So you think you're doing both simultaneously, but you're probably doing neither as well as you could be. And you're probably going to take more time than if you just did them linearly in some way.

GROSS: You write that two things that have stirred a revolution in neuroscience and our thinking about the brain are, one, the fact that brain cells can regenerate through our lifetimes, and, two, that we can change the brain circuitry through neuroplasticity. What does it mean that brain cells can regenerate through our lifetimes?

GUPTA: We long believed that brain cells, neurons would only sort of continue to develop or go through this neurogenesis, you know, new brain cell development process, at two different times, really, when you were very young and still developing your brain as a baby or if you've had some sort of injury. And at that point, the brain may start to either recruit new brain cells or even grow new brain cells.

What we've come to understand over the last decade is that even outside of those two conditions, just a normal life without an injury or as an adult, you can still grow new brain cells. That was a really pretty significant thing. Before that, the brain was thought to be largely immutable, sort of fixed, you know, and really measured only by its inputs and its outputs, you know, sort of a black box of sorts. We've obviously been able to explore the brain differently. And we've been able to see this neurogenesis - evidence of this neurogenesis throughout our entire lives, which is - which was really a remarkable finding and, I think, very inspiring, as well.

GROSS: So what does this mean on a practical level?

GUPTA: What this means is that you can continue to build new brain cells that can have connections with other brain cells and, as a result, form, you know, new pathways throughout your brain. We use our entire brain throughout our lives. The idea that we use, you know, 10 to 20% - that is not - that's a myth. But think of it more like this. If you think of your brain just as sort of the surface of the earth or maybe just a city, within that city, there's a few big metropolitan areas where people are spending most of their time, you know, the - where they work, maybe where they shop, things like that. But all the roads to get to these different places are constantly in use.

The idea - when you start to build new brain cells, it's like saying in this big city in which I live, instead of having three buildings and just a bunch of roads, I'm building 10 buildings. I'm building a bunch of different areas that are of great function and interest to my brain. And so you're using the same amount of brain, but you're using these parts of the brain now to have buildings instead of parking lots, essentially. And as a result, you can do more. You can see patterns that you would otherwise miss. You may be faster at processing things. Whatever it may be. But that's sort of the biggest idea, I think, around neurogenesis in the healthy brain is that you're simply able to create more of these paths and trails and even new buildings in places.

GROSS: So is the act of learning something new what is generating new brain cells?

GUPTA: I think the act of learning new things, the act of experiencing something new or even doing something that's typical for you but in a different way can all generate these new brain cells and these new pathways, these new functional pathways throughout the brain. And I think that's the most critical thing is that you can use the same roads and go to the same buildings you always go to. And pretty soon, you'll be really good at that. That's the practice makes perfect part of things.

But as you have these new experiences, these new learnings, these new activities - whatever they may be - something that gets you out of your comfort zone, maybe, is how I described it, you will start to build new things within your brain, new destinations within your brain, new paths throughout your brain. It's - that's the reserve in your brain that you're building by simply doing these things on a somewhat regular basis.

GROSS: A lot of people assume you kind of lose the ability to learn new things at a certain age or to create new habits or new patterns of behavior. Is that true?

GUPTA: I really don't think that that's true. I mean, it would be fair to say that, you know, the brain, like any other organ if you were to look at it, it ages. That shouldn't surprise anybody. It ages. It's going to change, the brain itself. Just the physical matter of the brain is going to change as you get older. But in terms of what it can do - processing speed, the ability to learn new things, all of that - that is not limited. Perhaps some of your senses start to diminish, your eyesight - you may need reading glasses - your hearing, things like that. But your ability to actually be able to process, to understand, to apply, that really - not only does it not change it, it can actually get sharper, can get better as you get older if you continue to use it. It is sort of the use it or lose it phenomenon when it comes to the brain if you think of the brain like a muscle, which, I think, is a fair metaphor.

GROSS: Do you think a healthy brain is measured by how well you can memorize things? How do you measure what a healthy brain is?

GUPTA: I think a healthy brain is really measured by - beyond the basic critical functions of being able to get you through your day, the activities of daily living, all those things, it's really about your happiness and how much joy you have. I know - which sounds euphemistic, but if the - if your brain is designed to, obviously, take care of the critical functions - breathing, respiration, heart rate, blood pressure, things like that, your brainstem functions - beyond that, it's the things that get you through the day and create a - the most positive living experience you can have. That's really what the brain should be doing if the brain is working well and we're treating the brain right.

GROSS: So your brain shouldn't be saying, you didn't do a good enough job, nobody likes you (laughter), that's not a healthy brain?

GUPTA: That's a toxic brain.

GROSS: That's a toxic brain, right.

GUPTA: That's a toxic brain. And we all live with that because we live in a society in which that is what we're exposed to often. But the brain, left to its own devices, has one purpose and it's to just serve the individual. And so how does any organ serve you? You wouldn't ask about the heart that way. A happy heart is a healthy heart. A happy brain is a healthy brain. But they all exist to serve the individual, that's it, to serve no one else.

GROSS: All right. Let's take a short break here. If you're just joining us, my guest is Dr. Sanjay Gupta, CNN's chief medical correspondent. His new book is called "Keep Sharp: Build A Better Brain At Any Age." We'll be right back after a break. This is FRESH AIR.

(SOUNDBITE OF HERLIN RILEY'S "TWELVE'S IT")

GROSS: This is FRESH AIR. Let's get back to my interview with Dr. Sanjay Gupta, CNN's chief medical correspondent. He's also a practicing neurosurgeon. His new book is called "Keep Sharp: Build A Better Brain At Any Age."

So it's encouraging to hear you say that you can keep creating new pathways in your brain, you could do it even when you're older. Let me balance that with the discouraging news that age 24 is the peak from your brain. So is it all downhill after 24?

GUPTA: I think the idea that we have these sort of artificial peaks in terms of what the brain can and cannot do is already starting to become a little bit antiquated thinking. It was only over the last decade or so - Terry, that we even thought that the brain could create new brain cells and become more plastic. So we had this sort of image in our head that, you know, it was this peak performance at a certain age and then sort of downhill after that. I don't want to be hyperbolic or euphemistic. I mean, it is true that the - our organs age and we age. And that's true. That's part of life.

But the brain, perhaps more than any other organ, I think can actually become better as we get older. There's certain things that are, you know, going to diminish - our senses, for example. But when it comes to things like judgment, when it comes to language, when it comes to your overall capacity to find happiness, those things can actually improve as you get older. And I keep coming back to this happiness and joy thing because, oftentimes, people think about these types of lifestyle changes in terms of preventing illness later. But when we really look at this, we find that there's benefit to doing these things right now for your brain.

Like, if I tell you to eat right and exercise and don't smoke and do all those things and nothing will happen to you, well, first of all, that's not the most inspiring, right? You do all these things, you work so hard and then nothing happens to me. Why am I doing it? Well, to prevent illness. Well, how do I know that I wouldn't have had the illness anyway? How do I know it was all this hard work that I did? The brain is different in that you can close the loop right now. You can feel better right away as a result of these actions. And one of the ways that you feel better is you just - you feel happier. You feel more productive. You feel like a better daughter or better son, better spouse, whatever it may be. You want to get out of bed in the morning. You feel like you have a life of purpose.

Whatever it is, those things you can feel now as a result of these things, which I just think is important. You know, as a doc, we're always trying to inspire our patients to do the right thing - by telling them this will help you 20, 30 years from now, it's pretty tough to make the case. If I tell you that it's going to help you right now and, by the way, the way that it helps is that it makes you feel happier, it's pretty compelling.

GROSS: Two really important things for a healthy brain are exercise, which you've talked about. That kind of surprised me. I never really associated that with the brain...

GUPTA: (Laughter).

GROSS: ...But also sleep. Sleep is really important for good brain function. What happens while we're sleeping?

GUPTA: The brain is not at rest the way people might imagine it to be when we're sleeping. I think a lot of people, you know, they realize that we dream and we do other things. So the brain can be quite active. But I think there's several important things that are happening, but two that I really focused on. One is that is the time when we really do consolidate memories. So you've had all these interesting experiences throughout your day, people that you've met, conversations you've had, experiences you've had, whatever it may be. You have these things in part because you want to remember them and add them to your life narrative.

That process of actually putting them in the memory book, if you will, putting them in the Terry Gross life narrative book, really happens at the time that you sleep. That's the consolidation of memory sort of phase. Some of it is actually placing the memory. Some of it is moving memories from short term to longer term memory and those sorts of things. So you have to be able to sleep well in order to remember well. And you also have to be able to sleep well in order to forget well, because you want to - in order to make that life narrative as cohesive as possible, you're doing a lot of editing along the way. You're getting rid of some things, you're adding things - the whole process, just like you might write a paper. A lot of that's happening while you sleep.

Another more recent finding about sleep is that there is a sort of rinse cycle that's happening when you sleep, a rinse cycle that allows certain neurotrophic factors to bathe the brain but also to remove certain waste as well from the basic metabolic processes that are happening in the organ, the brain, just like any other organ in the body. It's almost like the lymphatic system in the body. The lymphatic system is draining lymph - you know, in your lymph, draining waste away from your body. That's happening in the brain as well. So during sleep, it's really this consolidation of memories, this removal of waste and this nourishing of the brain that takes place more efficiently than at any other time during the day.

GROSS: Do you think that memory games and crossword puzzles are actually helpful in training your brain to remember more things and be sharper?

GUPTA: I think that crossword puzzles and brain training exercises can be quite helpful at making the roads in your brain that you use a lot already - keeping them strong, preventing them from needing construction and things like that. It's kind of the practice makes perfect part of your brain. And some of the brain games can actually increase your processing speed, the speed at which you process new content, new information. But I really do draw a line between that and keeping a brain sharper and building cognitive reserve throughout your life. That's different. You want to be doing different things in order to build that reserve as opposed to doing the same thing better and better. There's a role for both. But if it's cognitive reserve you're looking for, doing different things, things that get you outside your comfort zone, it's probably going to have a much bigger payoff.

GROSS: Well, let me reintroduce you here. If you're just joining us, my guest is Dr. Sanjay Gupta, CNN's chief medical correspondent and author of the new book "Keep Sharp: Build A Better Brain At Any Age." We'll talk more after a break. I'm Terry Gross. And this is FRESH AIR.

(SOUNDBITE OF PETROS KLAMPANIS' "EASY COME EASY GO")

GROSS: This is FRESH AIR. I'm Terry Gross. Let's get back to my interview with Dr. Sanjay Gupta, CNN's chief medical correspondent. He's also been a practicing neurosurgeon for about 20 years. His new book is all about the brain. He debunks myths, explains the latest research about the brain's ability to keep learning new things - no matter what your age - and how to keep the brain healthy and functioning at its best.

So to sum up, for a healthy brain, you recommend movement. You like the idea of strenuous exercise. You recommend a good, healthy diet and say that a heart-healthy diet is also a brain-healthy diet. Get a lot of sleep - how much would you suggest?

GUPTA: I think, sleepwise, seven to nine hours seems like the right amount. Everyone is...

GROSS: Nine hours? (Laughter).

GUPTA: Seven to nine hours, if you can do it, if you can do it. You know, if you're dreaming in the morning right before you wake up, that's a pretty good sign. That probably means that you've spent a fair amount of your evening, your night, consolidating memories and going through the rinse cycle, and, you know, you wake up with some morning dreams. If you can do that, that's a pretty good sign. Everyone's different, and that's something that I really try to focus on in the book as well because we love the sort of blanket advice on things. But, you know, 7 billion people on the planet - we're all going to be a little different. But if you want to put a range on things, seven to nine hours of sleep.

GROSS: Give me the honest answer to this question - how many hours of sleep do you get between performing brain surgery and being a CNN medical correspondent and a father of three?

GUPTA: Yeah. You know, Terry, I'm not getting enough sleep. And, you know, I hate to be one of those people who's not practicing what he preaches, but even though I think I know the right thing to do doesn't mean that I always do it, and I'm just very honest and transparent about that. It's been a really hard year. I mean...

GROSS: I know (laughter).

GUPTA: It's been a really tough year. I mean, since the beginning of 2020, Terry, I have been, every day - weekends included - waking up around 5 o'clock in the morning, sometimes 4:45. Part of the reason is I need to speak to people on the other side of the globe. And they're ending their days as I'm beginning mine, and I want to speak to them. You know, I wanted to speak to folks in China from where the virus - you know, they had some of the earliest data. I wanted to speak to them about the outbreak. I wanted to speak to them about their vaccine development. Were the antivirals working? How are the hospitals doing? What are they learning in terms of critical care?

I mean, I was so head-down into the story. I'm a neurosurgeon, not an infectious disease doctor, but nothing really mattered when you're dealing with a novel virus. There's so much that we're still learning. So I became so head-down in this story, in this issue and learning everything about it that I was waking up at 4:45 in the morning. And because I do television and sometimes the shows don't go off the air till 11 o'clock at night (laughter), you know, I'm getting five or six hours a night for a year. And it's affected me, for sure. It's not ideal.

GROSS: How has it affected you?

GUPTA: I'm not as clear. I'm not as happy. I'm tired. I'm not as organized. I'm a super organized, fastidious individual. I mean, that is kind of my calling card. Everything is always organized. Right now I'm sitting here talking to you in my basement closet.

GROSS: (Laughter).

GUPTA: I - my - I don't even know if I have my shirt on inside out or not as I'm talking - luckily, you can't see me. My - I have a little cot that I put down here in my basement room, windowless basement room, where I sleep a lot. It's littered with shirts that probably need to be washed and ties and papers from this year, things that I continue to want to read, you know, as we're moving into the next phase of this pandemic. I have all these notes about the vaccine. I got my own vaccine. I took copious notes on the vaccine before I received it myself. It's just - it's - my mind and my space are cluttered. And I know that I could be a lot better if I simply got sleep. And I'm not being hyperbolic. It's true. But I've just had a hard time getting there this year.

GROSS: Understood. Why are you sleeping on a cot in the basement?

GUPTA: Well, because a lot of times, I don't want to wake up my family. I have two dogs. I have three kids, my wife. And if I'm going to bed around midnight and need to be back up at 4:45, all that means is I'm going to wake up the whole house twice. So the dogs start barking if I go upstairs, and that wakes up the girls. And, you know, just no one's happy in that case, so at least I can be the only one unhappy in that scenario (laughter) if I simply sleep - I don't sleep there all the time. But there's a lot of times when I just - you know, it's just easier, especially if there's a lot going on. The kids have Zoom school in the morning and tests and things like that. It just - it's easier.

I'm privileged, I think, to be able to work from home so I can see the family, you know, a fair amount. I can pop up during the day and say hi and sometimes have meals together. But most of the time, I'm in this windowless basement. It's sort of this sensory-deprived environment, which just - everywhere I look, I mean, I got Post-its all over the walls. Everywhere you look, it's COVID. I'm totally immersed in the world of COVID.

GROSS: You got the first dose of your COVID vaccine on camera live on CNN. I applaud you for doing that. I think it's really important to show people doing that because people have so many different fears and conspiracy theories about the vaccine. But here's my question - did you try really hard not to wince as the needle went into your arm?

(LAUGHTER)

GROSS: Because it was like, hey, this is great; I don't feel a thing, you know (laughter).

GUPTA: I got to tell you, I really did not feel a thing. It was funny. I was talking to this woman who is the dean of the Morehouse School of Medicine. And we were both doing this simultaneously. There's a lot of vaccine hesitancy among Black American community. She's an African American woman. She wanted to get the vaccine to demonstrate her willingness to do this. So we were talking.

And I knew that they were about to, you know, give me the vaccine, but I think - we had a really good nurse who - I don't know, it's just - it was just her touch. It's a small needle. It's not as vicious even as some of the other vaccines that you get. So I really didn't feel a thing. And I had a bit of a sore arm that didn't show up actually until several hours later, but not so sore that I couldn't throw a baseball if I needed to. That's always sort of my measure. Can I still be functional with the arm? And I get another shot in three weeks after the first one. It was pretty straightforward.

GROSS: All right. Let's take a short break here. If you're just joining us, my guest is Dr. Sanjay Gupta, CNN's chief medical correspondent. His new book is called "Keep Sharp: Build A Better Brain At Any Age." We'll be right back after a break. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: This is FRESH AIR. Let's get back to my interview with Dr. Sanjay Gupta, CNN's chief medical correspondent. He's also a practicing neurosurgeon. His new book is called "Keep Sharp: Build A Better Brain At Any Age."

How have you dealt with, on a journalistic level, on just a pure emotional level, with the fact that the Trump administration, President Trump himself, have not followed the guidelines that the medical experts, including medical experts in his own administration, have put forward? You know, he's not really recommended masks. I mean, he'll pay lip service to occasionally. He - there were so many times he wasn't wearing them. There were White House spreads because people weren't wearing masks. I mean, you know - you're a doctor and a journalist. You know that masks and the vaccine will help prevent the spread, social distancing. How, especially earlier on, did you deal with that?

GUPTA: It was just infuriating, Terry. It - and I don't think you needed to be a doctor or a journalist to see that. I mean, the idea that you were not addressing the most significant public health crisis of our lifetime in any kind of meaningful way and that so many thousands and now hundreds of thousands of people were dying was really, really discouraging.

I mean, I resisted a couple of things. I resisted to draw too many comparisons between the United States and other countries because, you know, every country is a bit different. But South Korea had their first patient confirmed diagnosis on the same day as the first patient in the United States. They're a country of 50 million. We're 350 million. So they're smaller, obviously. But their deaths have been in the hundreds, and we've had hundreds of thousands of deaths. I hate to say it, but that's a fair comparison, and it's infuriating that the best that we could do was be the worst in the world.

So many of these deaths are preventable - so many of them. And nobody who's lost a loved one to this disease - and I know so many families. You know, I talk to these families on a regular basis. Nobody wants to hear that. Nobody wants to hear that their loved one died a preventable death. But it's true. You know, so many of these deaths could have been prevented.

GROSS: Did you have any confrontations with people in the Trump administration or governors that were not doing due diligence and recommending masks?

GUPTA: I was at the - an early White House press conference where I asked President Trump questions about this. You know, it was - we were allowed to ask questions, and I asked him how he could sort of - given all that we knew at the time, why he still believed that this was no more dangerous than the flu, that - you know, that he had complete control over it, all these types of things.

I interviewed just about every member of the coronavirus task force at one point or another. They weren't necessarily confrontational because the task force, you know, they understood the science, even if they couldn't necessarily give the messages they wanted to the public. And so sometimes our interviews would revolve around that - how it's not so much understanding the science; it's understanding the messaging around the science.

I interviewed, I remember, Ambassador Birx in late November, early December of 2020 at the White House, and I was so stunned to walk into the White House at that time. We were actually in the Eisenhower Executive Office Building right next to the White House. And 15%, 20% of people were wearing masks inside that building. We had just spent all this time telling people that if you're going into public places outside of your household - indoors, especially - you should wear masks. At the White House, they were not doing that.

Ambassador Birx was chair of the coronavirus task force when she sat down to do this interview with me. She wore a mask. We were doing the interview indoors. The people who accompanied her to the interview, her assistants, were not wearing masks. It was just so strange to me.

GROSS: Wait - her own assistants were not wearing masks?

GUPTA: Not wearing masks.

GROSS: Why? Do you know?

GUPTA: Well, I don't know. But what they said when they saw us - us being, you know, our television crew, producers, camera folks. We're all inside. We've all sterilized the place. We're all wearing our masks, obviously. And they said something like, well, we should probably be wearing masks as well, but we're not. You know, I don't know that it wasn't that they didn't believe in this virus. What I think it really was, Terry - and this is more subjective - it's that they just didn't think it would affect them.

GROSS: You know, President Trump declared himself a stable genius after - I think this was right after taking a cognitive test. And in describing the test, he said that he was able to remember in sequence the words camera, man, woman - no, I'm sorry. Person - I just failed. Person, man, woman, camera, TV. I know somebody who had a concussion who had to take a similar test. Was he really being tested for some kind of brain injury or, you know, cognitive deficiency?

GUPTA: The Montreal cognitive test is - it's a screening test to try and determine whether or not someone has some sort of very obvious discernible pathology. That's - it's a screening test. It really - it's not that it's not a useful test because it can be useful in the setting of pathology of some sort or a concussion, as you mentioned - something like that. But in order to really determine whether or not someone has dementia, especially, you know, mild or moderate dementia, it's - actually requires a lot of testing.

And this is something Richard Isaacson taught me, a neurologist who's been focused on this for some time - is that you have to not only conduct many tests, but you have to conduct them over time because you're really trying to get an idea of where the person is. And was that a singular event where the person had an abnormality, or is it something that's persistent.

So we made a lot of that test - and we meaning the president made a lot of that test, declaring himself a stable genius. But that's a screening test that is very simple and, frankly, is designed to be passed by everybody who takes it unless there's some sort of obvious, very obvious problem.

GROSS: And even just the words - I'm curious about this - person, man, woman, camera, TV. They're all related. You know, a person is a man or a woman - or genderqueer, but that's not in the test. So, you know, person, man, woman, camera, TV. For Trump, people are associated with cameras. He watches so much television. Camera and TV are associated. In these tests, are the words usually associated or do they want to see if you can make memories with words that have no obvious association?

GUPTA: Right. No. They want to pick disparate sort of objects, you know?

GROSS: Right. So when he gave this as an example of what he was asked to remember, it was probably nothing like what he was asked to remember.

GUPTA: Right. So either he wasn't telling us what he actually - I mean, I don't know if you watched that interview that he did with - I believe that was the doctor from Fox News, but he kind of just was motioning around the area at the time. So I'm not sure that those were even the objects that he was being asked to remember during the actual cognitive exam.

Frankly, I'm not even sure that he had a actually thorough cognitive exam of any sort. I mean, we don't know that for sure, and we're not required to know that. There's no mandate that he actually share that he had the test or what the results of the test were.

So I think that was - a proper cognitive exam to remember objects like that would not have chosen those objects. They're usually inanimate objects, first of all, and they usually have no relationship to each other.

GROSS: Well, I think it's time for another break, so let me reintroduce you. My guest is Dr. Sanjay Gupta, CNN's chief medical correspondent. His new book is called "Keep Sharp: Build A Better Brain At Any Age." We'll be right back after a break. This is FRESH AIR.

(SOUNDBITE OF CHUCHO VALDES' "OCHUN")

GROSS: This is FRESH AIR. Let's get back to my interview with Dr. Sanjay Gupta, CNN's chief medical correspondent. He's also a practicing neurosurgeon. His new book is called "Keep Sharp: Build A Better Brain At Any Age."

There is a story you tell in your new book about brain surgery that you performed - I forget if it was Iraq or Afghanistan - but it involved a Black & Decker drill (laughter) because you didn't have any of the things that you needed to perform this very delicate surgery. We're just about out of time, but could you briefly describe the workarounds that you came up with to perform surgery in a place where you didn't have what you needed?

GUPTA: This was one of the most indelible experiences of my life and one that I'll never forget. I was covering the war over there as a reporter, but I was traveling with this group of naval doctors, colloquially known as the Devil Docs. And we'd been together for weeks at that point, and we really got to know each other well. They knew that I was a neurosurgeon.

And one day, a lieutenant came in having been shot in the head by a sniper. Now, they weren't really anticipating a lot of these types of injuries because of helmets and things like that, but here was the case. And they thought this lieutenant had died. They couldn't find a pulse in the chaos of war. When they brought him into the Devil Docs tent area, they realized that he was alive.

And that was the point where they basically said, hey, can you take off your journalist cap and put on your surgeon's cap? And again, these are people that I really had been - I knew well, now. For weeks, we'd been traveling, hopscotching around the desert in the middle of a war.

The thing is, when you don't plan on having these types of injuries, you don't necessarily have the equipment to do the types of operations necessary. They had a lot of general surgery equipment and orthopedic equipment, but they didn't have equipment to do what is called a craniectomy or craniotomy, which is basically when you're removing part of the skull. We typically have very specialized drills to do that - perforators and drills and things like that.

So I needed to take off the pressure on this young man's brain. That is the most crucial thing that you can do in the setting of an acute brain injury like that is just to take the pressure off. And the only way that I could really do that was to have some sort of drill. And I realized, as I was frantically sort of looking around this dusty desert tent, that the Black & Decker drill, which we'd been using to put up the tents as we were moving around the desert, was the only drill that really existed.

So we took the bits off the drill - and there were several bits - and we put them in this autoclave solution to sterilize them; put a glove - a sterile glove - on the drill itself so I could hold the drill with, you know, my sterile hands, my sterile gloved hands. And then basically perforated, if you will - kind of created a score line around the area of bone that I wanted to remove to decompresses his brain and just kept going back and forth like you would in basic woodworking or anything else to the point where it became a scored line so thin that I could essentially break off that portion of his skull and decompress his brain. That's what needed to happen, and that's the way that I got it done - taking that bone off - and then removing the blood collection and taking out the area of pathology in his brain.

GROSS: Then you had to find something to substitute for the membrane around the brain.

GUPTA: Yeah. So the outer layer of the brain is called the dura. And that is the part that basically insulates the brain from the outside world, keeps it sterile and hygienic. Because one of the biggest problems you can have is actually developing meningitis or encephalitis. That can be as deadly as the initial injury itself.

We had nothing to use as dura. And I knew that if I didn't close his brain in some way, he would likely become infected, especially in that environment. We weren't in some sterile operating room, we were in a dusty desert tent. It was as sterile as we could make it, but it wasn't, you know, it wasn't what we wanted.

So what we did was, we - the only sterile thing that we could really think of at that point was the inside of an IV bag. So there was IV bags everywhere, and I knew that the inside of the IV bag was going to be sterile. So we basically took an IV bag, I filleted it open and then used the inner part of the IV bag. I sewed that into his existing dura and essentially recreated the outer layer of his brain with this synthetic plastic-like material. Then, I was able to just close him up, wrap him - wrap his head - and be fairly confident that he at least would not develop an infection.

GROSS: So how is he now?

GUPTA: He's doing really well. He's got some left-hand weakness. But he got married, he's going to graduate school and he's living his life.

GROSS: So one more question. When you're functioning as a doctor in the U.S., you're performing neurosurgery in Georgia, in Atlanta. When patients see you or know that you're going to be their neurosurgeon, what's the reaction you get to being, you know, a famous doctor on CNN?

GUPTA: You know, it's one of three reactions typically. I mean, sometimes, you know, patients are coming in for trauma, and they just - there's no knowledge of who their doctor really is. They're not either conscious or sort of aware of that.

Another reaction - I mean, I get patients who want to come see me from all over the world now because, for whatever reason, they think if you're on TV, you must be good. I think I'm good, but it's not because I'm on TV, you know? So that's kind of always a funny thing to me. I mean, I always tell them I'm happy to recommend excellent neurosurgeons in your area.

The third reaction, which probably would be my reaction, is that, hey, look, I know you're a neurosurgeon. I hear you're good. You also do television. While you're focused on my operation, I want you just to be focused on my operation. No TV, (laughter) you know, in the interim, which I totally understand, respect and get. I balance these two lives pretty well. And, you know, I think that they - you know, my patients understand that.

GROSS: Well, Dr. Gupta, thank you so much for talking with us.

GUPTA: Terry, thank you. What an honor.

GROSS: Dr. Sanjay Gupta is a neurosurgeon and CNN's chief medical correspondent. His new book is called "Keep Sharp: Build A Better Brain At Any Age."

Tomorrow on FRESH AIR, our guest will be journalist Kai Strittmatter, whose new book is about growing surveillance and social control in China. In some cities, citizens are monitored and given social credit scores for their behavior. Those who ignore traffic lights or fail to shovel snow might find their travel or Internet access restricted. I hope you'll join us.

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GROSS: FRESH AIR's executive producer is Danny Miller. Our technical director and engineer is Audrey Bentham. Our interviews and reviews are produced and edited by Amy Salit, Phyllis Myers, Sam Briger, Lauren Krenzel, Heidi Saman, Therese Madden, Ann Marie Baldonado, Thea Chaloner, Seth Kelley and Kayla Lattimore. Our associate producer of digital media is Molly Seavy-Nesper. Roberta Shorrock directs the show. I'm Terry Gross.

(SOUNDBITE OF BRED MEHLDAU'S "HAPPY TUNE") Transcript provided by NPR, Copyright NPR.