Harvard-trained neuroscientist and bestselling novelist Lisa Genova speaks to us about how the brain forms memories and the best way to sustain brain health (spoiler: sleep and exercise are extremely important).
Harvard-trained neuroscientist and bestselling novelist Lisa Genova speaks to us about how the brain forms memories and the best way to sustain brain health (spoiler: sleep and exercise are extremely important).
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Heather Reisman:
Hi, I’m Heather Reisman, and this is Well Said, a podcast on the art and science of living well. This podcast is brought to you by Indigo.
Lisa Genova:
We can influence whether we ever get to Alzheimer’s, which is very exciting. We can literally prevent this disease with the right kinds of lifestyle.
Heather Reisman:
That’s Lisa Genova. You might know her from her 2007 novel, Still Alice, which drew us in with its powerful depiction of early-onset Alzheimer’s and that disease’s impact on relationships, memory, and self-identity. A neuroscientist by profession, Lisa joins us today to discuss her newest book, Remember, a non-fiction exploration of how our brains make memories, why we often forget things, when that might be a sign of something serious, and when it is perfectly normal. Most importantly, we will look at what we can do to keep our brains functioning at their best, well into the future.
Lisa, welcome to Well Said. It really it is a privilege to have you here with us today.
Lisa Genova:
Oh, Heather, thank you. I am so excited to do this with you. Thank you, thank you, thank you for all of the wonderful support you’ve given me over the years.
Heather Reisman:
There’s so much I want to explore with you here today, starting at the very beginning. What drew you into the field of neuroscience?
Lisa Genova:
Ahh. Well, I was always a scientist. I was definitely interested in biology. How do we work? How does the heart pump? How does the kidney filter? But then when it came to the brain, I took my first course in neuroscience when I was a sophomore in college, and at the same time I read a book called The Man Who Mistook His Wife for A Hat, by Oliver Sacks. And those two things—that course and that book—instantly solidified it for me. I was in. I was hooked, curious, passionate. Yes. I knew I wanted to be a neuroscientist then.
Heather Reisman:
Your book, Remember, really drew me in and right from the first page. It just feels like essential reading for anyone with a brain—which is to say, every one of us. So let’s jump right in. You say that memory is essential to the experience of being human; it’s central to who we are. But what exactly is memory?
Lisa Genova:
Right. So let’s start by what it’s not, because there’s some general misconceptions out there. So, your brain and your memory, they are not a video camera recording a constant stream of every sight, and sound, and emotion, and information that you’re exposed to. You don’t have a memory bank. You’re not storing information in a file cabinet or someplace that you can withdraw from or hit “play” and watch. Memory is really a reconstruction job. It is the collection of neurons that were involved in what you paid attention to and cared about, connected into a neural circuit, so that I can see, and hear, and feel, and know that memory as a singular thing.
So how do we form one to begin with? So it’s not enough to just see what’s going on around you with your eyes; you actually have to pay attention to it. And what we pay attention to gives you a key as to what you’ll remember. You pay attention to things that are new and surprising. You pay attention to things that are emotional, meaningful. These are the moments, the information, things that are repeated over and over so that your brain has a chance to rehearse and practice. Those are the things that we remember.
Heather Reisman:
You touch on something really important here: the idea of paying attention. And we’re going to come back to that in moment. But before we get to that, you explain in the book that we actually have different kinds of memory. Can you share a little more about that?
Lisa Genova:
Yes. So, you have what’s called your “semantic memory.” This is your memory for the stuff that you know. This is the Wikipedia of your brain. The facts, the stuff you learned in school. So who’s the first president, what’s your address. Your biographical information is in there, your résumé, the colours of the rainbow, what’s 6 times 6. That’s the stuff-you-know memory—the semantic memory.
Your episodic memory is for the stuff that happened. This is, “Oh, remember when…?” So this is memory attached to a time and place. So this is, you know, the history of your life, the story of your life.
And there’s also your muscle memory. So muscle memories do not live in your muscles; they live in your brain. These are memories for the choreography, the procedure of how to do things. So it’s everything from how do you brush your teeth, drive a car, type, walk.
The last kind, I almost think of the last kind as a kind of forgetting, but it’s called “prospective memory.” This is your memory for what you plan to do later. It’s your to-do list for your future you. It is, “Oh, I need to remember to pick up the dry cleaning, go to the bank before it closes.” So that’s prospective memory.
Heather Reisman:
You say that paying attention is important.
Lisa Genova:
Yes.
Heather Reisman:
That is we think we’re forgetting…
Lisa Genova:
Umm-hmm.
Heather Reisman:
… but actually we’re not, we’re forgetting because we never encoded to begin with. Do I have that right?
Lisa Genova:
Yeah. So it’s like we’re blaming our memory for like, “I can’t remember where I put my phone, or my keys.” or “Where’s my glasses?” or “Where did I park my car?” “Oh, my God, do I have Alzheimer’s? Am I losing my mind? Why can I never remember where I put my stuff?” So we’re actually blaming our memory. We’re saying, “Oh, I have such a terrible memory. Oh, I keep forgetting.” But your memory was never involved in the first place. So the first necessary ingredient, in forming a new memory that you can consciously retrieve later, is your attention.
Heather Reisman:
So while we’re on this really important subject of paying attention, do you worry at all that our growing addiction to our phones and social media is degrading our ability to pay attention?
Lisa Genova:
Yes, you’re onto something here. So first has to do with your divided attention. My daughter is 21, and her generation really does this sort of Snapchatting, while watching TV, while having a conversation with me. And you know, me too, so I’ll be scrolling Instagram and doing something else at the same time. So anytime you’re dividing your attention, I am fractioning off the amount of attention I can give to any one thing. And so yes, your memory for any of those things when your attention is divided will not be robust enough, will not be full enough, to form a strong enough memory. You might form a memory of that moment; you’re not going to be able to form that memory as richly and as strongly as you might like.
Heather Reisman:
So you’re saying you have to pay attention to make new memories. You know all of this so richly and deeply. Do you find yourself actively consciously paying attention, wanting to pay attention? Do you actively push away distraction? Or do you say it’s almost impossible?
Lisa Genova:
Oh, I love this question. Because yes, I’m human, and I at times will be scrolling through social media mindlessly at the end of the day. The good news is I’m quicker at catching myself when I’m doing something that’s counterproductive for my memory and wellbeing. Like, “Oh. What am I doing? I’m on social media, like mindlessly scrolling, when what I really need is a good night’s sleep, because sleep is so important for my memory today and for preventing Alzheimer’s tomorrow.” Even say it out loud or in your mind’s ear: “I am putting my glasses on the desk.” And then walk away. Give your brain a chance to remember where they are. You know, just notice where you are. You let the sensory information add to your attention. It’s the sensory information plus attention equals memory.
Heather Reisman:
That is so good. The sensory information plus attention equals memory.
So now let’s talk a little bit more about forgetting. Why do we forget?
Lisa Genova:
Mm. So, right. So memory is not a war inside your brain between remembering the good guy and forgetting the bad guy. I think people think that all forgetting is bad. And it’s not. Forgetting is actually very useful to us. If it’s important for our survival to remember what’s meaningful, emotional, new, surprising, repeated, then it’s actually useful for us to remember what’s sort of the important, and forget the noise. Right?
So what’s the noise? We forget what’s same-old same-old, not emotional. So we don’t remember the routine habitual moments of day-to-day life. And this is OK. And so it helps us, for the things that we do care about, those come into the foreground and we have the opportunity to remember those things for 80 years. Right? Yes.
Heather Reisman:
So there’s good forgetting, and then there’s some not-so-good forgetting. Which brings us to the discussion about Alzheimer’s. And I’d like to start with this: what’s the difference between Alzheimer’s and dementia?
Lisa Genova:
The difference between Alzheimer’s and dementia—these words are used interchangeably a lot, and they’re not the same thing. Dementia is a symptom; it’s an umbrella term that means you’re having difficulty with language, memory, and cognition out of what would be normal for your age and education level. Symptoms of dementia are the hallmark symptom of Alzheimer’s. It’s the primary symptom of this disease, so they’re often used interchangeably.
Heather Reisman:
So dementia is just the symptom of forgetting or not being to recall?
Lisa Genova:
So let me back up a little bit. The primary reason I wrote this book is to help people understand the distinction between normal forgetting and forgetting due to Alzheimer’s. Because, as we age, you know, especially as you get into your 50s and 60s and beyond, there is this terror, this anxiety, this constant stress that, “I’m at risk for Alzheimer’s and it’s coming for me.” People, you know, spiral into the black hole and think, “Oh, my God, I already have it. Here it is. I have Alzheimer’s. It’s coming.” And you’re not. So most of what we forget—whether you’re 20 or 70—is a normal part of owning a human brain. There’s this weird assumption and expectation out there that people think memory is supposed to be perfect. And I want to help people be mindful of what is Alzheimer’s. Because if you have it, the earlier you know, the better you can manage, and cope with, and deal with, you know, what life is.
The good news is because it takes 15 to 20 years, and because the way we live can influence whether we ever get to Alzheimer’s—which is very exciting—we can literally prevent this disease with the right kinds of lifestyle. So there’s lots of things we can do.
Heather Reisman:
Great. Let’s get at it, to the meat of what you’re writing about. What are the best things that we can do to sustain our brain health and avoid, or at the very least push way into the future, any chance of getting Alzheimer’s?
Lisa Genova:
This is a great question. So let me begin with sleep. The sleep science data are super-clear. We need seven to nine hours of sleep, as human beings, to function optimally. So let me give you three things that are going on. I used to think of—when I was young, I used to think that sleep was just this time of doing nothing. My God, what a waste of time. But we’re very biologically busy while we sleep.
So the first thing that happens is all the sensory information, the content of what I paid attention to and cared about today, becomes consolidated into a lasting, linked neural circuit—a memory—while I sleep. And so if you don’t get enough sleep tonight, your hippocampus might not have had enough time to do its job, and so you’ll wake up the next morning not having fully formed, or maybe not having formed at all, some of your memories for what happened yesterday.
The second thing is, if I don’t get enough sleep tonight, when I wake up tomorrow I’m going to be feeling really groggy, I’m exhausted. My frontal lobe is going to be dragging itself to its day job. And one of its most important jobs is paying attention. Right? So we all know when we’ve had a horrible night’s sleep, it’s, “Well, what did you say? I’m sorry, I wasn’t paying attention.” So if I can’t pay attention today, I’m not going to be able to form new memories.
So just by getting a bad night’s sleep, I have a form of amnesia today. I can’t remember well what happened yesterday, and I’m not going to create good strong memories of what’s going on today.
The third thing has to do with Alzheimer’s but it’s the janitor cells won’t have had enough time to clear away amyloid. And so you’re going to be that much closer to that tipping point in getting Alzheimer’s if you are chronically sleep-deprived. So I’ve just scared a lot of people, because a lot of us are chronically sleep-deprived. Try to put this priority higher on your list. What can you do?
So I make it a priority. So at night when I have that urge to scroll through social media, I try to go like, “Shut that down. No. Get to sleep. It’s so much more important for me to get an extra hour of sleep than this hour of scrolling. Better for my health. It’s going to do me a good service.” Your room, is it too hot? Your body temperature actually needs to decrease by a couple of degrees for you to fall asleep. So make sure your room is cool. There’s lots of strategies. You can Google a guy named Matthew Walker. He wrote a book called Why We Sleep, which you would love, Heather. It’s phenomenal. All right, that’s sleep.
Exercise is the other biggie, next to sleep. If I told you there was a pill that reduced your risk of Alzheimer’s by 50 per cent, would you take it? Definitely. Well, all of the studies on exercise show that it dramatically reduces your risk of developing Alzheimer’s—from anywhere from a third to a half.
Heather Reisman:
That is stunning!
Lisa Genova:
Yes. It’s big.
Heather Reisman:
Exercise reduces anywhere from a third to a half. And when you say exercise, are you saying, like is a brisk walk for 40 minutes considered exercise?
Lisa Genova:
Yes.
Heather Reisman:
Do I need to sweat it like crazy to get that 50 per cent reduction?
Lisa Genova:
So, so far, the minimum of what we’ve seen in terms of what’s been studied, it’s a brisk daily walk for 30 minutes, four times a week. So this is, when I say a brisk walk, it’s walking as if you’re in a hurry. Right?
Heather Reisman:
Right.
Lisa Genova:
So that kind of a walk. We also know that strength training—the working with weights, or working with resistance of your body weight—is also helpful. So anything that involves movement. If you’re out—if you’re dancing, if you’re playing a game. I also like to tell folks social isolation is a risk factor; we’re not meant to be alone. Social isolation is really bad for our memory today, our wellbeing today, and actually has been shown to increase your risk of Alzheimer’s. So if you can combine exercise with walking with a friend. So get a friend; be in conversation while you walk. Also, to add to that, your walk, do it in a different neighbourhood.
Heather Reisman:
Oh, yeah.
Lisa Genova:
Pick a different setting. Now you’re inviting new information. You will wake up your senses to what’s going on around you. You know, pay attention to new things, you’ll make new memories.
Pick a different setting. Now you’re inviting new information. You will wake up your senses to what’s going on around you. You know, pay attention to new things, you’ll make new memories.
Too much stress, though, can jam us up if we’re trying to retrieve a memory. Right? We’ve all had this experience: you’ve studied for a test, but you’re really nervous and anxious and stressed about it, and go to take it and you blank, you choke. You can’t retrieve what you know if you’re too stressed.
So the good news there is I can’t stop stress but we can do something about our response to it. So when we get stressed, what happens is we get flooded with adrenaline and cortisol—and it’s supposed to shut off. When it’s chronic stress, the shut-off valve breaks and we just stay flooded with cortisol; and this is really bad for your brain and your hippocampus. It turns out that the reason yoga, and meditation, and mindfulness, and gratitude, and even exercise, one of the reasons it works is because it restores the shut-off valve. It restores your cortisol levels, so they’re not high anymore. And so your hippocampus can grow back.
When you are running for your life, which is what your body feels like when you have adrenaline and cortisol running through you—when you’re running through your life, you are not breathing calmly through your nose. You’re going [panting sounds]. And so the stressful, urgent, emergency situation causes us to breathe like that. But then we can also flip it around. If I’m breathing calmly, I am telling my brain and my body that I am safe. And my molecules will respond in kind, and cortisol levels will come down.
Heather Reisman:
I think the joy of this is you’re trying to say we don’t have to do everything perfectly. We can decide to just step-by-step change a bit the way we’re living.
Lisa Genova:
Yeah. Definitely.
[music]
Heather Reisman:
We always like to end the episode with a couple of fun questions. Let me start with this: what book, or couple of books, have you read that have had a really deep impact on you?
Lisa Genova:
Well, definitely, The Man Who Mistook His Wife for A Hat, by Oliver Sacks. And so many like that. Like The Diving Bell and the Butterfly. I love what David Eagleman puts out there, so: Incognito, Livewired.
Heather Reisman:
So many of my favourites. We actually hosted David Eagleman at an Indigo event a few months ago. His writing on the brain is so inspiring.
Lisa Genova:
In terms of fiction—and this is so hard for me, because I have so many friends who are authors, so I’m apologizing to all my friends for leaving any and all of you out but—just off the top of my head: Alice Hoffman.
Heather Reisman:
Oh, I love her.
Lisa Genova:
The Dovekeepers is one of my favourites.
Heather Reisman:
That is exactly the one that I came very close to turning into a movie. Interesting.
Lisa Genova:
All the Light We Cannot See, by Anthony Doerr, was like a masterclass. And more recently, The Book of Longings, by Sue Monk Kidd. And then I’ve been reading tons of non-fiction lately. I’m just in that world right now. And so just to like give some to some readers. I loved The Body, by Bill Bryson, in terms of communicating biological information to folks.
Heather Reisman:
It sounds like we really share a passion for many of the same writers. Such a great list you’ve given us.
What does living with intention mean to you?
Lisa Genova:
Oh, I love that question. So, living with intention for me means being mindful of what my purpose is. And so I try to communicate, mostly through story, what it feels like to live with neurological diseases, disorders, mental illness; so that they feel seen and heard; to humanize what their life experience is; and to help others develop empathy and compassion for someone they might be afraid of, or intimidated by, or unsure of how to be with. So. And this book really—this book, Remember, is more about providing that kind of empathy and gentle compassion to ourselves. Right? We have these human brains that forget, and most of the time that’s really, really OK. So just my intention is to help us understand each other from a place of feeling, rather than just knowing.
Heather Reisman:
Lisa, every time I get the opportunity to be with you, to interview you, to experience your writing—fiction or non-fiction—I do really feel it as a gift. So thank you. Thank you for writing. Thank you for the new book, Remember. And thank you for taking the time to be with us today.
Lisa Genova:
Oh, my gosh, Heather, thank you so much. I appreciate all that you are and all that you do. I’m a big fan and admirer of yours for a long time now. Thank you.
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Heather Reisman:
Thank you for tuning in to our conversation with Lisa Genova. For more ideas to help you live well, including the book featured in this episode, Remember, visit indigo.ca/podcast. If you enjoyed this episode, please do leave us a rating on Apple Podcasts. You can follow us on Apple Podcasts or wherever you listen.
Well Said was produced for Indigo Inc. by Vocal Fry Studios and is hosted by me, Heather Reisman.
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Want to hear more from Lisa Genova? Use the code “REMEMBER” on indigo.ca for 30% off the List Price on Lisa Genova’s latest book, and first work of non-fiction, titled, Remember: The Science of Memory and the Art of Forgetting. Offer runs June 9th to June 22nd, 2021, on indigo.ca and excludes shipping costs. Not valid on previous purchases.
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