My name is Lisa Genova. I am an author and neuroscientist. My book is Remember: The Science of Memory and the Art of Forgetting. Chapter one, how your memory works. So, I decided to take a break from my gig as a novelist to write this non-fiction book because I've been talking about Alzheimer's using Still Alice as a vehicle for that conversation for over a decade, trying to help folks understand what it feels like to have Alzheimer's and to recognize what those symptoms of dementia are. But what I found was over and over is that everybody over the age of 40, certainly over 50, 60, 70, they think that all kinds of forgetting mean they have Alzheimer's. So these folks would corner me in the ladies room or wait to the end of the book signing line and sort of confess to me what's going on in their lives and looking almost for a diagnosis in this very conversation. And so they'd say things to me like, "Well, I'm always forgetting names and if I don't write down what I have to do later, I won't remember to do it and I'm always walking into the kitchen and I don't know why I'm in there." And so these people are panicked and afraid and stressed out and really ashamed of these moments of forgetting which are actually totally normal. There are so many misconceptions with respect to memory. I think the biggest one in a nutshell has to do with the notion that people think that memory is supposed to be perfect. That our brains are supposed to remember everything that it encounters. And this simply isn't true. Our brains are not designed to remember people's names, to do something later, or to catalog everything we encounter. Even people who have phenomenal memories, people who are considered memory champions will forget the things that human brains forget. So for example, Akira Haraguchi, a retired engineer from Japan, decided that he wanted to memorize pi to as many digits as he could. And he was 69 years old when he decided he wanted to do this. He memorized pi, a non-re repeating patternless number to over 111,000 digits because he wanted to. This is amazing. And he's not a mathematical savant. He's not a genius, but he has a healthy human brain. And because he knows techniques that pair storytelling and meaning and visualization with all of those numbers, he's able to do this magical thing. But he also forgot his wife's birthday one year and he can forget why he's in his living room. So we as human beings have to accept a certain amount of forgetting in our lives. So memory is not a war in your brain between remembering the good guy and forgetting the bad guy. I think that a lot of us have that conception of what memory is. Human memory is amazing and it's fallible.

Neurologically speaking, what even is a memory? So memory is the constellation, the pattern of neural activity that represents the sights, sounds, smells, feelings, information, language that you experienced when you learned something in the first place reactivated as a neural circuit in your brain. So, your memory is not a video camera recording a constant stream of every sight and sound you encounter. There's no memory bank. I think a lot of people think that memories are stored in a place. And this is actually true for a lot of other things that go on in our brain. There's a physical location. There's a an address for where we process vision or language or movement. But memory is different. It's not in a file cabinet. It's not a DVD menu. Memory is located throughout your brain and all of the disperate places that are involved in what that memory consists of. So if I'm thinking of the sight and sound of Mickey Mouse, I'll have neurons in the back of my head. That's my occipital cortex. My visual cortex will be activated. Those represent what Mickey Mouse looks like. But the sound of Mickey Mouse is located somewhere else. That's in my auditory cortex. And so the circuit, the memory will involve the activation of neurons in those very different places. But that's the memory of what Mickey Mouse looks and sounds like for me. Your hippocampus is your memory weaver. This is the part of your brain that binds all of those disperate elements of what will become a singular pattern of neural activity, what will become a memory. So it links together the sights, the sounds, the smells, the feelings, the language, the information so that they become connected into a neural circuit. The hippocampus is a part of your brain that is essential for the formation of any new memories that you will later consciously be able to retrieve. And when you are recalling a memory, when you are recognizing something that you know, your brain is being activated in a similar manner to what it was when you actually experienced the information or learned the information in the first place. So the pattern of neural activity is based on what you paid attention to and learned in the first place. It will be recalled again. It will be reactivated. So, how do we know where memory is in the brain? How do we know that it's activated really all over your brain? We know this through brain imaging studies, through functional MRI studies. So, if I were to put you in a brain scanner and I were to show you while you're in there the sight and sound of Mickey Mouse and your brain is lighting up in specific areas of your brain, I take the image away and then I ask you to remember maybe five minutes later, ask you to remember that picture. The neuroiming will light up in different parts of your brain at first while it's searching. And then when you say, "I've got it." Your brain activity has landed on the exact same places in your brain that were lit up and activated when you were actually looking at the photo.

So there are four basic steps in creating a memory. The first is called encoding. This means that your brain takes all of the sights, the sounds, the smells, the tastes, the feelings, the information of what you learned or experienced and translates that into neurological language. The second step is called consolidation. Here, your brain links together all of the previously unrelated neural activity and connects them into a pattern of associated connections, a sort of neural circuit that can live for decades. The third step is storage. Your brain locks in this information by making enduring longlasting changes in your neural architecture. Changes in neuroanatomy and neurochemistry that are longlasting and persist long after you first learned or experienced the information. The last step is retrieval. So you got the information in. To remember it, you want to get the information out. So this means you can now activate this neural circuit. And so you can recall, revisit, reminisce, know something that happened or that you learned before. So there are three kinds of long-term memory. One is called episodic. This is your memory for the stuff that happened. This is the story of your life. This is oh remember when there is semantic. This is the stuff you know. Semantic memories are the facts and data, the information you learned in school, your autobiographical information. So, anytime you fill out a form, name, address, birth date, that's semantic memory. The third kind is called muscle memory. It's a little bit of a misnomer. Muscle memory doesn't live in your muscles. It lives in your brain. Muscle memory is the memorized choreography, the procedure for how to do things. So this actually lives in a part of your brain called the motor cortex. That part of your brain tells all of the voluntary muscles in your body what to do. So with concentrated focused practice and repetition, you can memorize and therefore know uh for the rest of your life how to brush your teeth, how to ride a bike, how to swing a golf club, all of the things that we know how to do, our u muscle memories.

So, what do our brains remember and what do they forget? Our human brains are pretty phenomenal at remembering what is meaningful, emotional, surprising or new, and what's repeated. They're pretty bad at remembering what's same old, same old, been there, done that, not emotional, not repeated. Our brains are also great at remembering things that are visual and where those things are in space. So evolutionarily, you can imagine that it was really important for our survival for us to remember where the food is, where safety is, where the predators live. And so our brains are really keyed into visual, spatial, what's meaningful. So we don't just remember where everything is. We remember where these things are that are important to our survival. Things that are emotional tend to be meaningful to us. So those two elements t are pretty tied together. So if if something's emotionally neutral, it's probably not that meaningful to me and I don't remember it. If it's highly emotional in some way, whether that's good or bad, joyful, I'm in love, grief, anger, our brains remember what we pay attention to. This isn't just about the facts and information and the sights and sounds of things that happened. It's also about your outlook. So this is where practices in gratitude might come into what do you remember the story of your life. Do you pay attention to the moments of joy and abundance and wonder and awe and love? And so if you do those memories will populate your life story. Or are you a pessimist? Are you focusing on what hasn't happened for you? the scarcity, the injustices. If that's what you focus on, your memories will be populated with the doom and gloom and the lack. One of my favorite studies with respect to meaning and memory has to do with taxi drivers. They gave seasoned taxi drivers and new taxi drivers a list of street names to memorize. If the street names were listed in the order that they can be driven, the seasoned taxi drivers did great. They were able to recall something close to 90% of the words on the list, whereas the newbie taxi drivers didn't do so well, significantly less. If however those street names were listed in random order, one street name doesn't lead geographically to the next, the seasoned taxi drivers lost their memory advantage because the the names of the streets now had no meaning one to the next. They were basically in meaningless order. The seasoned taxi drivers did just as poorly as the newbie taxi drivers. So meaning matters when it comes to memory. Meaning is king.

So how accurate are our memories? It depends on which kind of memory we're talking about. So if we're talking about semantic memory, this is the memory for the stuff you learned, the stuff you know, that's pretty stable and accurate. So for example, if you learned that 6 * 6 is 36 when you were in the third grade, you're not going to suddenly misremember that decades later as 6 * 6 is 75. that's not going to happen. Muscle memory is similar, similarly stable over time. So this is where the expression just like riding a bike comes in, right? So if you learn to brush your teeth or ride a bike or how to type, you're not going to forget how to do those things. And in fact, you can not ride a bike for decades and then get back on the bike and your brain will remember the choreography. You'll get on the bike and ride. Episodic memory is a little different. So again, episodic memory is your memory for the stuff that happened. That's a little strange. It turns out that every time we recall a memory for something that happened, we have the opportunity to change it. Often not consciously. When we recall a memory for something that happened, we might add a detail. We might leave a detail out. If somebody else experienced the same event, they might add some information that we agree with. And so we'll add that to our memory. Um maybe it's decades later and we're a we're an adult and the memories from childhood and we've had time to accumulate wisdom and a different perspective and we've maybe forgiven the the culprit in that event or we have a different world view and so we shape it a little differently. Our our mood and and our outlook is different today than it was when you were younger. We're also as human beings naturalborn storytellers. So, if there are pieces of information missing in my story or if there's a way I can embellish and make the story better, make it sound good, give it a nice beginning, middle, and end, I might supply that, not knowing that I'm consciously lying. I'm just providing information that makes sense to tell you the story of what happened. Here's the weird thing that happens. If we've revised the memory for what happened in any way whatsoever when we recall it, we store this version, this 2.0 version of the memory over the old version in our brain. So it overwrites the original. It's like hitting save in Microsoft Word. So you can imagine that with each retelling, the memory for what happened has the possibility of drifting further and further away from what you actually paid attention to. and and store it as memory to begin with. Sort of like the telephone game, right? So with each telling it might change a little bit and then I will store that story in my brain as if it were the memory that the the slice of reality that I actually experienced. I won't actually know what really happened and what didn't happen. And this is called confabulation.

So there's another kind of memory called prospective memory. This is your memory for your future you. This is your brain's to-do list. This is your, oh, sometime in the future I need to remember to do the following. So, they're things like pick up the dry cleaning, pay the bills. Oh, I need to remember to call my mother later. Our brains are not designed to do this. Perspective memory is fraught with failure. In fact, I actually think of it as a kind of forgetting rather than a kind of memory. So, here's what happens with perspective memory. You're asking your brain to remember something at a future time and place to do something. Unless the proper cue is there and available for you to notice at the right time in the right place, you will forget to do this. So, with practice, we can get good at remembering to do something at certain times of day. So, a lot of us are really good at remembering to brush our teeth before we go to bed because we've done this every night of our lives. For those of you who've raised kids, you know that this is not an ingrained memory yet because how many nights of your life do you tell your kids, "Go brush your teeth. Go brush your teeth." So, at some point though, we remember to do this without any aids or any help. Here's something interesting. If you're someone who takes medication at night, a great way to remember to take your medication is to pair this with a habit that you already have at that time of day. So, if you leave your heart medication out next to your toothbrush, then you will see that when you're brushing your teeth and know that it's the time of day to do that. If, however, you leave your heart medication in the cabinet out of sight, you will probably forget to take your heart medication unless you write it down. So many people come up to me so worried, saying, "If I don't write what I need to do later down, I'm going to forget to do it. That's got to mean I'm getting Alzheimer's." And I tell all of them, "No, it's your perspective memory. It's terrible. It's not cheating to write it down. It's actually good practice." And here's the example that really brings it home for people where they realize that they don't have weak memories and they don't have a failing memory and they don't have the early signs of Alzheimer's with respect to perspective memory. Airline pilots do not rely on their brains and their perspective memories to remember to lower the wheels before landing the plane. They outsource the job to a to-do list, a checklist. This is why we should all write it down. Put it in your phones. Put it in your calendar alerts. Make to-do lists. This is not a sign of weakness. This is good practice. Surgeons use checklists so they won't forget the surgical instruments from the bodies of the patients before they sew these patients up. Prior to the checklist, these very intelligent, smart, trained surgeons would regularly forget and leave surgical instruments in the bodies of their patients and sew them up. If you want to remember to pick up milk at the grocery store, write it down. For all of these memories, they benefit from repetition. The more we repeat a memory, the stronger it will be and the more likely we'll be able to retrieve it. So with respect to semantic memories, these are the memories for information and facts. So if you're studying for a test or a presentation, it will benefit from a lot of rehearsal. Same goes for muscle memory. If you're trying to learn to play a piece on the piano or a tennis serve, the saying practice makes perfect really does hold true here. The more you do it, the more those neural circuits will have a chance to become consolidated and strengthened and then become a memory where you can simply serve the tennis ball without having to think about this step, this step, this step, this step. all completely separate unlin steps become a linked neural circuit once you've got it memorized. So memory is phenomenal, but it's also a bit of a dunce. It's going to remember details from 50 years ago and it will forget what you had for lunch last week. You might remember the Hamlet saliloquy you memorized in 10th grade, but you can't remember who texted you yesterday. So, your memory is both everything and nothing in some ways.

Chapter 2. Eight techniques to enhance your memory. There are things that we can do to be less afraid, less panicked, have a better relationship with our memory today. The first essential ingredient in creating a memory that's going to last longer than this present moment is attention. If I don't give something my attention, my brain can't form a memory of it. So, when I can't find my keys or my phone or my glasses or I can't remember where I parked my car, a lot of people will come to me with those kinds of examples and think that they're getting Alzheimer's or that their memory is terrible. And I sort of smile to myself and then let them know, I'd bet pretty much everything I've got that this isn't a symptom of memory loss at all. Your memory was never even involved here. This is a symptom of distraction. If I put my glasses down and don't give it a moment's attention to notice where I've put this, my brain can't form a memory of where I've put my glasses. So 10 minutes later when I'm looking for them, I can't remember where they are because I never formed that memory to begin with. Here's a great example that I love that I think we can all relate to. Have you ever been driving a stretch of road that's familiar? a a regular route to work, a regular commute. So, the sights and sounds are stuff you already know. Probably not paying attention to them anymore. You're driving this stretch of road and maybe 10, 20 minutes go by and suddenly you think, "Oh my god, I don't remember any of the trip. Where am I? How did I get this far?" I regularly cross the Sagamore Bridge in Massachusetts and this is a really big fourlane structure. And I will very often be 10, 20 miles past this bridge and have suddenly wonder where am I and then realizing I'm over the bridge and I have no memory of having gone over it. No memory of crossing this fourlane colossal structure. My eyes were open. My brain saw the bridge. I drove over it. My muscle memory did exactly what it's supposed to do driving the car safely. But I have no conscious memory of having driven over a bridge only 10 minutes ago. By the way, I'm not asking my brain to remember something from childhood decades ago. I can't remember it because the bridge is familiar and we don't really pay attention to what's familiar and same old same old. I was probably listening to an audio book or lost in thought. So my attention was pulled elsewhere. And so the experience of driving over that bridge slipped out of my brain within seconds. gone without a trace, not consolidated into memory. So, interestingly, caffeine is actually good for memory because caffeine increases your attention. And by having an enhanced ability to attend, I now can have an enhanced ability to remember. So, anything that's an attention booster is going to be a memory booster. But you guys want to be careful of when you have that last dose of caffeine because caffeine interferes with a neurom modulator called a denisonin. A denisonin causes you to become drowsy. It's that step that's necessary for you to fall asleep. Caffeine interferes with a denisonin. The halflife of caffeine is five hours. Which means that five hours after I've had my latte, half the amount of caffeine is still in my brain and body. So if I have a cappuccino at 700 p.m. at midnight, I'm still going to have about 32 milligrams of caffeine buzzing around in my brain, interfering with the denisonin and maybe interfering with my ability to fall asleep. And now we know that sleep is super important for forming memories because the hippocampus consolidates memories while we sleep. So we don't want to offset the benefit we get from attention boosting with losing sleep tonight. So if you're, you know, if you're having trouble falling asleep at night, look at where your caffeine is during the day and maybe back it up a bit. So caffeine's good for memory. You just want to be careful that it's not compromising your sleep.

Repeating memories makes them stronger. The more we repeat, the more we practice, the more we rehearse a memory, we are strengthening those neural connections, making that neural circuit stronger and more likely to be fully retrieved. One of the ways that we can repeat a memory is by writing it down. So if I've experienced a certain number of things today and I keep a journal and I write some of these down at the end of the day, what I've chosen to write down will become a stronger, more reinforced memory in my brain. I will also have the opportunity to revisit that memory by reading it later. So the memories that represent what I wrote down will become stronger, but anything I've left out might actually be weakened by this because I've chosen a certain slice of reality to capture in pen and paper. I've now focused on that and I am reinforcing and reactivating those neurons. The one the neurons that I've left out, the experiences from that day that I did not include will probably be forgotten. So, we know that what you repeat gets remembered better. So, we remember what is repeated over and over again. But there's nuance here. If I just hammer the information over and over and over into my brain, I might remember it. But what's better is if I space that out over time. So, for example, let's say I have an exam in one week and I'm going to study for seven hours. I can study for seven hours the day before the exam or I could study for one hour every day that week. Turns out I will remember the information far better if I space it out one hour a week rather than seven hours the night before. Another way to better remember this information has to do with self- testing. So again, I can hammer and hammer the information into my brain and I might remember it or I can flip it and also try to retrieve the information as I'm learning it. Because here's what happens. If I'm trying to consolidate something into memory and I'm only putting the information in, I'm traveling one way on the neurons. If I then try to recall the information, I'm pulling the information out. Now I'm going the other way. this this birectional highway of information in the memory really helps strengthen that circuit far more than just passively reading the information. So this is like flashc cards folks, right? So instead of just reading the list of vocabulary words over and over again, read the word and see if you can come up with the answer. Flip it over. Oh, okay. You'll learn faster and better that way.

With respect to memory, acute stress isn't bad for memory, but there are some nuances here. So, when you're studying for a test or for a presentation that you have to give, the kind of memory that you're trying to create and then retrieve is semantic memory. This is the memory for facts and information, the stuff you know. And stress will have an impact on your ability to both form those memories and retrieve them. So, a certain amount of stress is good for both situations, for getting the memory into your brain and retrieving it out, but too much will put you in a state of overwhelm. I think we've all experienced this. So, have you ever studied for an exam and you know the information cold? You got it. And then you go in for the test, but you're really stressed because you really want to get an A and you're super nervous. You're too nervous. You're too stressed and you you choke. You can't remember what you know. you can't retrieve the information and you jammed up because you're too stressed. So, a certain amount is great and optimal for remembering, but too much is going to put you in overwhelm and cause you to draw a blank. This is also true for muscle memory. So, if you're a baseball player and you're up at bat and the count is three and two and it's bottom of the ninth and the score is tied and the bases are loaded, but maybe you could tolerate a lot of stress and you need that. Maybe you're at the top of that inverted U and that's your optimal amount of stress and it's going to mobilize your body to react and you're going to be able to execute the memory of how to swing a baseball bat perfectly and you hit a home run. But maybe that situation is way too stressful for you and it puts you into overwhelm. Too much stress is going to cause you to not be able to retrieve the memory of how to hit a baseball perfectly. Now you're in your head and you're thinking about do this, adjust that. Oh, no, no, no. You're gonna you're gonna strike out. We also want to get enough sleep. So, you don't want to pull an allnighter. Your hippocampus consolidates the information you're learning into a lasting memory that you can consciously retrieve while you sleep. So, if you don't get a good night's sleep before the exam, your hippocampus has not had a chance to do its job. And so you'll be spilling out information that isn't really locked into your brain in a great way. And so you'll either not do a great job on that test or maybe you'll pull it off. But if this is information you care to know later, you're probably not going to because it didn't have a chance to form into a lasting memory. Context also matters. So it turns out that memories are most robustly and fully and confidently retrieved if the context of retrieval matches the context that was there when we formed the memory in the first place. So what does that mean? If I'm studying for a test and I'm listening to Mozart while eating sour patch gummy bears and I've got a lavender scented candle and I'm drinking mocha frappuccinos. I am best served to recall that information on test day if I'm eating sour gummies, maybe listening to Mozart, got some lavender lotion on, and sipping on a mocha frappuccino. The context will match what was available when I was learning it and can serve as one of the cues to trigger the neural circuit, right? Because those things were available while I was learning. So, anything that while I'm learning those vocabulary words, I'm also maybe pulling in some of the sights, the sounds, the tastes, the feelings, the things going on around and in me. So, am I caffeinated while I learn something? Am I depressed while I'm learning something? Am I tired while I'm learning something? So, I won't want to take that test listening to Eminem, snacking on uh, you know, kale chips and, you know, drinking lemonade. You want to match the conditions that were available while you were learning something when you want to retrieve it and that will give you the best opportunity to recall it.

So, interestingly, people with the best imaginations probably have the best memories and here's why. So, again, we remember what's meaningful, surprising, emotional, um, visual. And so if you can be imaginative, if you can be creative imaginatively, you are more likely to attach associations to what you're trying to remember. That will help you remember what you're trying to know and recall. Let me give you an example. So let's say I'm not going to rely on my perspective memory to buy milk later today at the grocery store because perspective memory is terrible. And like the airline pilots, I know I should outsource the job and write it down. Let's say I'm not going to write it down. I don't have a pen and paper ready and I don't have my phone and I'm not going to write it down. How might I remember to buy milk later? Well, rather than just try and keep it in there on its own, what if I attach associations to it? So, what if I can come up with a really imaginative way to remember milk? So, here's what I could do. I could picture Dwayne the Rock Johnson milking a cow on my kitchen table. I picked a room in a place that my brain knows really well. Your brain loves where things are. So, I've just given it a very strangely imagined scenario that is attached to the thing I need to buy later. So now when I go to the store to buy milk, oh, that's so easy to remember now. And I bet every time you buy a milk now, you'll remember this, too. So, our brains are not designed to remember people's names. They're actually not designed to remember pronouns. So, names, movie titles, book titles, cities. If you notice that these go missing regularly on you and you're like, "Oh, what's the name of the actor in that movie? What's the name of that book?" It's totally normal. Think of people's names. These are abstract concepts. They live in neurological culde-sacs in your brain. Ultimately, there's only one way in to that house that lives at the end of that street. There's no other way to get there. Whereas common nouns live in the intersection of Main Street, USA, thousands of ways in and out, easy to grab. But so, say you're trying to remember someone's name. It's not impossible. We can do this, but it's tougher. So, can we supply more associations to the person's name to give us a chance? So in psychology, this is called the Baker Baker paradox. If I'm trying to remember your name and your name is Mr. Baker, that's really tough for me to remember. Abstract concept. But if I were asked to remember the word baker, what can go on in my brain is I can picture a baker. I can picture someone wearing an apron and he's got flour on his face and he's got a spatula in his hand and oh, I remember the bakery I used to love as a kid and we used to get danishes there on Sundays. So now I've got all of these associations in my brain attaching to that word baker. It gives me a chance to hook into it. So if I'm meeting someone, I want there are a number of things I can do. I can try to create associations that go along with their name. This person's name reminds me of someone I know. Um I can say their name over and over again. We remember what is repeated. So if you say, "Hi, my name is Sarah." and I say, "Sarah, nice to meet you." So now I've heard the name twice. Repeat the name without sounding creepy and you will give your brain a better chance to remember it. But add add associations if you can. So if you meet a guy named Mr. Baker, add the associations. Think of apple pie and smell it and he you know, picture him wearing that apron with some some flower on his face and it will help you associate it. And then later on after you've gone home, you can then rehearse it a bit and say, "What was the name of that guy I met?" And hopefully you come up with this name. And now you've done this thing I've talked about with self- testing, which is that you've given those neurons even more of a chance to become reactivated and strengthened. So technology is kind of interesting to me because I think it wields a double-edged sword. So, on the one hand, we're we live pretty distracted lives today. We're pulled in so many directions between the text alerts and the emails and the Snapchat and Instagram and the constantly scrolling feeds and and responding to emails. It's a lot. And if we're distracted, we can't pay attention. If I can't pay attention, I can't make new memories. So, that's a downside. Um, you know, if I want to have a lot of memories for what happened in my life, I need to be available to what's happening. And so, if I'm always on my phone and I'm looking down, my best friend from kindergarten might be in the line in Starbucks in front of me and I won't notice and have a chance to have that happy reunion because I'm my attention and my head is buried in my phone. There's definitely downside to social media with respect to mood disorders and bullying and self-image and all of that. Yet, there's a lot of upside as well. So, with respect to technology today, life is an open book test. I don't have to remember everything. If I can't remember the name of an actor in a movie, I can Google it. A lot of people are worried that if they look up the names that go missing, that are on the tip of their tongue. Oh, what's the name of that actor? They worry if they Google it that they're cheating, that they're going to give themselves digital amnesia and make their memories weaker. Looking up a word, googling a word that's on the tip of your tongue isn't cheating. It will not cause digital amnesia. It will not make your memory weaker in any way. Likewise, suffering through the mental pain of trying to come up with the word on your own. You're like, "Oh, I know it begins with J. Hold on, wait, what is it?" And you can't come up with it for hours. Probably will pop into consciousness before bed, but that's another story. Um, doesn't make your memory any stronger. We think that we need to come up with it on our own or we're cheating. And this just isn't so. So, life is now an open book test, folks. We can Google anything that we can't remember in a moment's notice and then use that information to continue thinking, to continue the conversation, to learn more. So, I don't need to know all the details of the Pelpeneisian War. I can look it up and use that information to think about things and make connections and have conversations and and live a fuller life. In some ways, social media, plenty of downside. On the upside, your chronology of what happened can be captured there quite nicely. Somewhat like a photo album, but even more in depth because now I've got the photos with the captions. I can have people tagged. I can have be geo tagged for the location. Um, all of that information, the comments can be a rich trigger, an association, a cue that can remind me of that event and day in my life. So, in going through your profile page on Facebook or Instagram, it's almost like a, you know, the analog would be a photo album. It's a nice way of this visual diary of revisiting and reinforcing and strengthening your memories for what happened. What I would love for you to take away from all of this is that your memory is amazing. It is limitless in what it's capable of remembering if you supply it with the right kind of information. if you supply it with the right kind of tools and associations. And it's wildly imperfect. And that's just the price of owning a human brain. Forgetting is a normal part of being human.

Chapter 3. How to protect your brain from Alzheimer's. Alzheimer's begins with a protein called amaloid beta. either too much is made or not enough is cleared away. And if that happens, it's a sticky protein. It'll bind to itself and form amalloid plaques. And if enough amalloid plaques accumulate in your brain at some point reaches a tipping point, which then triggers a molecular cascade that causes neuropibrillary tangles, neuroinflammation, cell death, and all of the symptoms that we classically know of as Alzheimer's. Prior to that tipping point, you're symptom free. You're not diagnosed with Alzheimer's yet. It's sort of like having high cholesterol and heart disease, right? If you have high cholesterol, it doesn't mean you're going to have a heart attack. It means that you're below that level. So, below the tipping point, your symptoms of forgetting are all normal. These are the why did I come in this room? Where did I put my phone? Where did I park my car? Oh, what's his name? I need to remember to buy something later and I forgot. That's totally normal. After the tipping point, the glitches in memory, formation, and retrieval are different. So, it's normal to forget the actor who played Tony Soprano in the HBO series The Sopranos. Can't remember that guy's name. What is it? It's not normal to forget a lot of words all day long and common words. So now, not just proper nouns, but oh, what's the the name of that thing I use to write with? The thing to write with. What's that pen? Yes. If those kinds of words go missing a dozen times a day, that's not normal forgetting. It might not be Alzheimer's. There are lots of reasons why you could be forgetting that are actually quite treatable, such as a B12 deficiency, chronic sleep deprivation, depression. Um, but it's something that can be addressed. Another difference between normal forgetting and forgetting due to Alzheimer's is though, you know, where did I put my So, a lot of people will tell me, you know, I went to the mall and I shopped for only an hour and then I came out of the mall into the garage and I couldn't remember where I parked my car and they're freaked out and stressed out and panicked and worried that this is a symptom of Alzheimer's. And here's how you can tell the difference. If you get out into that garage and are you can't remember if you parked on level three or level four. I think it was three, but maybe it was four. You probably didn't pay attention to where you parked your car. And you can't form a consciously held retrievable memory unless you paid attention. Probably zipped off into that mall. You were texting, you were talking, you were busy doing the next thing. And that's probably why you don't remember if it's on three or four. If you have Alzheimer's, it's different. You get to that garage and you think, "I don't remember how I got here." Or you're looking at your car, you're standing right in front of it and you don't recognize it as yours. So, the distinction is very clear.

Alzheimer's begins in your hippocampus. So, this accumulation of amaloid plaques, the first place it begins in your brain is the very place in your brain that's responsible for forming new memories. So, the very first symptoms of Alzheimer's will be not remembering what someone said a few minutes ago, repeating yourself over and over because you don't remember what you just said, not remembering what happened earlier today, not remembering really well what happened last week, even if it was really emotional, meaningful, new, surprising, or repeated. The things that you would normally remember from last week won't get consolidated because your hippocampus is under attack. Alzheimer's will move. It doesn't just stay in your hippocampus. It invades your frontal lobe, so you'll have problems with problem solving, decision making, thinking. It invades parts of your brain that have to do with where things are in space, so you might get lost in the neighborhood you've lived in your whole life. It will invade the parts of your brain that have to do with language, so you'll start having trouble coming up with words more and more. the disease will move on to your lyic system and cause disregulation in mood and emotion. So you'll see deregulation and disinhibition with respect to rage and grief and lust. So your grandfather who might have always been very even killed and gentle is suddenly very emotionally violent or has bursts of rage. For 98% of us, Alzheimer's is not our brain's destiny. So, our risk of developing Alzheimer's is a combination of the genes we've inherited from mom and dad and how we live. So, there's your genetic predisposition. Maybe you have some increased likelihood of developing Alzheimer's based on those genes. Maybe you have some resistance against Alzheimer's based on those genes. But then there's how we live and that really does play a huge role in whether or not our amaloid plaques will reach that tipping point and will begin becoming symptomatic for Alzheimer's. So what are the lifestyle factors that influence our brain health with respect to Alzheimer's? sleep, diet, exercise, stress, and learning new things. So, these aren't particularly sexy, but they work. And I think understanding why they work can help us actually implement them. I think a lot of us just want the pill. People come up to me all the time, "What's the supplement? What can I take that will prevent Alzheimer's?" The good news is a lot of these lifestyle factors work as well as any pill that we might develop for preventing Alzheimer's. We just have to do them. So sleep is not a state of doing nothing where you're unconscious and it's a waste of time. It's not, oh, I'll sleep when I'm dead. You're very biologically busy while you sleep. And there are a number of things that are going on in your brain while you sleep with respect to memory that are very important. So let's go over three of them. Number one, while you sleep, your hippocampus is busy consolidating the memories that you paid attention to and cared about that were meaningful. The stuff that happened, the stuff you learn today are being formed into a lasting enduring neurological memory by your hippocampus while you sleep. So what happens if you don't get enough sleep? Your hippocampus might not have had enough time to do the job. And so your memories from what happened yesterday and the stuff you learned yesterday might not be fully formed today or they might not be formed at all. Number two, if I got a horrible night's sleep last night, I'm going to wake up today and my frontal lobe is going to have a hard time dragging itself to its day job. And one of its most important jobs is paying attention. So, we've all experienced this, right? If you have a terrible night's sleep, you have a really hard time paying attention to what people are saying and what's going on today. And if I can't pay attention to what's going on today, what am I not going to be able to do well today? form new memories. So, by not getting a good night's sleep last night, I'm walking around today with a form of amnesia. Really, the third thing has to do with Alzheimer's. While you sleep, there are cells in your brain called gleal cells. These are the janitors of your brain. It's the sewage and sanitation department. They get really busy clearing away all of the metabolic debris that accumulated in your brain while you were in the business of being awake. And one of the things it critically clears away is amaloid beta. So if you don't get enough sleep, the gal cells won't have enough time to do their jobs and you'll wake up in the morning with some extra amaloid in your brain that wasn't cleared away. If this happens over decades, right, 15 to 20 years of amaloid plaque accumulation. If you're chronically sleepd deprived, you are increasing your risk of developing Alzheimer's by reaching that tipping point. diet. There have been many really good longitudinal studies that have shown that being on a Mediterranean or mine diet can reduce your risk of Alzheimer's from anywhere from a third to a half. That's significant, folks. So, what does this mean? This means eating the rainbow. The green leafy vegetables, the brightly colored fruits and berries, fatty fishes, nuts, beans, olive oils. That's the food that's going to support your brain health and help you prevent Alzheimer's. Exercise. Again, we've got a lot of studies now and they all show consistently the same thing. exercise, specifically aerobic exercise. We're talking a brisk walk for 30 minutes four to five times a week is enough to decrease your amaloid plaque levels and reduce your risk of developing Alzheimer's by again anywhere to a third to a half. Again, this is significant. If I offered you a pill that would reduce your risk of Alzheimer's by 50%, you'd take it. So, we want to get up and move around.

So sleep is not a state of doing nothing where you're unconscious and it's a waste of time. It's not, oh, I'll sleep when I'm dead. You're very biologically busy while you sleep. And there are a number of things that are going on in your brain while you sleep with respect to memory that are very important. So let's go over three of them. Number one, while you sleep, your hippocampus is busy consolidating the memories that you paid attention to and cared about that were meaningful. The stuff that happened, the stuff you learn today are being formed into a lasting enduring neurological memory by your hippocampus while you sleep. So what happens if you don't get enough sleep? Your hippocampus might not have had enough time to do the job. And so your memories from what happened yesterday and the stuff you learned yesterday might not be fully formed today or they might not be formed at all. Number two, if I got a horrible night's sleep last night, I'm going to wake up today and my frontal lobe is going to have a hard time dragging itself to its day job. And one of its most important jobs is paying attention. So, we've all experienced this, right? If you have a terrible night's sleep, you have a really hard time paying attention to what people are saying and what's going on today. And if I can't pay attention to what's going on today, what am I not going to be able to do well today? form new memories. So, by not getting a good night's sleep last night, I'm walking around today with a form of amnesia. Really, the third thing has to do with Alzheimer's. While you sleep, there are cells in your brain called gleal cells. These are the janitors of your brain. It's the sewage and sanitation department. They get really busy clearing away all of the metabolic debris that accumulated in your brain while you were in the business of being awake. And one of the things it critically clears away is amaloid beta. So if you don't get enough sleep, the gal cells won't have enough time to do their jobs and you'll wake up in the morning with some extra amaloid in your brain that wasn't cleared away. If this happens over decades, right, 15 to 20 years of amaloid plaque accumulation. If you're chronically sleepd deprived, you are increasing your risk of developing Alzheimer's by reaching that tipping point. diet. There have been many really good longitudinal studies that have shown that being on a Mediterranean or mine diet can reduce your risk of Alzheimer's from anywhere from a third to a half. That's significant, folks. So, what does this mean? This means eating the rainbow. The green leafy vegetables, the brightly colored fruits and berries, fatty fishes, nuts, beans, olive oils. That's the food that's going to support your brain health and help you prevent Alzheimer's. Exercise. Again, we've got a lot of studies now and they all show consistently the same thing. exercise, specifically aerobic exercise. We're talking a brisk walk for 30 minutes four to five times a week is enough to decrease your amaloid plaque levels and reduce your risk of developing Alzheimer's by again anywhere to a third to a half. Again, this is significant. If I offered you a pill that would reduce your risk of Alzheimer's by 50%, you'd take it. So, we want to get up and move around. So stress is meant to be an acute quick on andoff phenomenon. So evolutionarily we experience some sort of threat or danger or crisis an emergency and the stress response is activated in our brains and bodies. And so what does that mean? It means that your brain releases hormones that release stress hormones from your adrenal glands. The two workhorse stress hormones are adrenaline and cortisol. These hormones mobilize your brain and body to respond, to fight, to flee, to react quickly, not to think. Your frontal lobe actually shuts down in when you're in stress, fight or flight. You don't want to sort of weigh the pros and cons of what I should do. Let me take time to think about that. No, this is a reactive quick go do something right now. But then it's also a quick off. So cortisol actually acts on receptors back in your brain to flip the switch and turn the whole thing off. It's a nice neat negative feedback loop. So cortisol and adrenaline levels will then be restored and you will go back to normal. So for example, getting out of bed in the morning activates the stress response a little bit. A little bit of cortisol first thing in the morning just to get up out of bed. If you have to hit the brakes in your car, if the car in front of you stops short to get ready for that Zoom presentation, you want a certain amount of alertness, readiness, mobilizing you, that's the acute stress response. And that can be good for memory. That can help you create new memories for stuff that happened. There's a bit of an inverted U to this in terms of the curve. So, a little bit of stress will help. There's an optimal amount of acute stress that varies person to person for remembering things best and performing things best. Again, muscle memories are a kind of memory. So, for some baseball players, if they're up at bat and the count's three and two and the bases are loaded and it's bottom of the ninth, that's a that level of stress is great for them. They're going to hit the ball. But for another player, that's too much. He's in overwhelm and he's going to strike out. though acutely an acute stress is can be good for memory to a point. What happens if we're chronically stressed? Well, again, we're not talking about lions in in the savannah. Mostly, we're talking about psychological stress here today. Our thoughts are our predators. The top three psychological stressors are social isolation, uncertainty, and a perceived lack of control. A lot of us tick all of these boxes all the time. So, what happens in your brain and body if you're exposed to chronic, unrelenting stress, unmanaged stress, and how does that affect your memory? Under chronic stress, the feedback loop can break. The receptors in your brain that normally bind to cortisol to shut everything off can become downregulated or desensitized. And so your body will just keep dumping adrenaline and cortisol and it can't shut off. This is bad for memory. It it will keep you in a constant state of fight or flight. You will constantly feel like you're breathing really rapidly. You're anxious and worried and you are actually shrinking your hippocampus. The part of your brain that's essential for forming all of your consciously held memories is going to be smaller. you're going to have less of a structure available to do that job. You will be inhibiting neurogenesis, which is the birth of new neurons in your hippocampus. So, you will have a harder time creating new memories. You will have a harder time retrieving the stuff you already know. And you're shrinking your hippocampus, which can put it at risk for developing Alzheimer's in the future. The very good news about all of this, because I probably just scared everyone, is that there are things that we can do to combat stress. This is where things like yoga, meditation, mindfulness, and exercise come into play. All of these have been shown through MRI studies, brain imaging studies to restore the size of people's hippocampus who have been chronically stressed. And so, a quick word on meditation. A lot of people are intimidated by meditation. They sort of know that this is probably good for them in lots of ways. Um, but maybe don't know how to do it. Think that that they have to do it for at least 30 minutes. They don't have the time. I don't know how to turn off my thoughts. Here's a 9-second meditation I love to show people because you can do this at any point in your day to help restore your cortisol levels and to help save your hippocampus and your ability to remember. Close your eyes if you can. If you're in the middle of a Zoom meeting or driving your car, don't. But if you can close your eyes, it's helpful. Breathe in through your nose to the count of four. Hold it for a second and then breathe out through your nose to the count of four. And notice how you feel. Here's what's going on. When the world is chaotic and threatening and scary and dangerous, it triggers the stress response in our body and our physiology reacts in kind. So when we're running when we're stressed out, when we're stressed out by something that's happening the in the world, our physiology is maybe running for its life or it's it's getting ready to fight or flee. But your breathing is if you're being chased by a lion, evolutionarily, the stress response causes you to breathe like this. [panting] You are never breathing calmly in and out through your nose. So while the world can impact our physiology, we can flip this. We can also reverse it and inform our physiology to do something else. So by breathing slowly in and out through your nose, you are telling your brain and body that you are safe. So we know through brain scan imaging studies that folks who are under the same kinds of psychological stress but who exercise regularly who practice meditation who practice yoga will be immune to those stress effects. Their cortisol levels will remain low. It will it will restore their cortisol levels if they were high and it will restore the size of your hippocampus.

Learning new things. So, let's say you haven't done any of those things I just mentioned. Let's say you've been sleepdeprived for decades. You love bacon and you really don't like to exercise. You've been you've been sedentary for a long time. Let's say your amaloid plaque levels have reached that tipping point and it's triggered the cascade that causes Alzheimer's. You should be symptomatic at this point, but you might not be. If you've lived a life where you're cognitively active, you're regularly learning new things, you are building what we call a cognitive reserve. Every time you learn something new, you're building new synapses. You're building new neural connections. You have trillions of connections in your brain. And it's not a static number. You're constantly building new synapses every time you form a new memory. Think about that. for you to remember today what happened yesterday means that your brain had to change and one of the ways it changed is that it built a new neural connection built a number of new neural connections so what does this have to do with Alzheimer's if I have some Alzheimer's disease pathology present in my brain and it's blocking some synapses those amaloid plaques are gunking up the connections between a certain number of neurons those neurons will be impassible communication won't happen there. But what if I've built a lot of redundant connections? I've got an abundance and a redundancy in connections. I can dance around those roadblocks. I can take detours and still get to the memory I'm trying to get to because memory is the neural circuit, the pattern of associated connections. There are a number of ways to access that memory if I have built a lot of connections within it. So learning new things gives us a way to build an Alzheimer's resistant brain. So people are worried about their memory. And I love people being concerned about Alzheimer's and wanting to understand what those symptoms are and to be mindful of how they can support brain health to prevent Alzheimer's. But all the other stuff, all of the the 99% of forgetting that happens to all of us is normal. The other really good news is Alzheimer's doesn't happen overnight. This accumulation of amalloid plaques takes 15 to 20 years and it is not predetermined by your genes. Only 2% of folks have Alzheimer's that is 100% inherited. For the rest of us, that accumulation of amalloid plaques, which happens over the course of 15 to 20 years, can be influenced by how we live. And so, there's a lot we can do to prevent us from getting Alzheimer's. Want to support the channel? Join the Big Think Members community where you get access to videos early and free.