453. 7 facts you need to know about your brain

0:05 Hello everybody, I'm Gemma Speig and welcome back to The Psychology of Your Twenties, the podcast where we talk through the biggest changes, moments and transitions of our twenties and what they mean for our psychology.

0:25 Hello everybody, welcome back to the show, welcome back to the podcast. It is so great to have you here back for another episode as we of course break down the psychology of our 20s. I have a very fun, or at least I think it's fun, very fascinating at least, in-depth science episode for you all today about the big hunk of flesh in your skull, your brain. I think most of us know a few interesting facts about the brain.

0:54 We know it's 75% water, that there are things called neurons and synapses. Maybe you can even label the four major lobes if you paid close enough attention in year 10 biology. But do you actually understand why your brain behaves the way it does? Why you can remember an embarrassing moment from 12 years ago, but forget what you had for breakfast yesterday. And certain habits seem impossible to break whilst others you don't have to try very hard for.

1:26 These are all questions to do with your brain and to do with how this thing in your head is structured and works. The more neuroscience I read, the more humbled I become because every thought you have, every memory you keep, every emotion you feel, even pain, every decision you make is the product of an organ weighing just over a kilo that somehow manages to build your entire experience of reality. And yet most of us go through life knowing surprisingly very little. So today I wanted to do something a little bit different. Rather than just focusing on one psychological concept, we are going to explore seven of the most surprising and genuinely useful facts about your brain that you may not know. And even if you

2:19 do provide a little bit more of the little known research, behind those facts, just to give you something interesting to talk about at dinner parties, but also so that you understand yourself better. More than that, I really do hope that you'll just leave with a greater appreciation for the genuine miracle that is your brain and how to take its quirks and its strange idiosyncrasies and use them to your advantage. Without further ado, let's get into it. Let's come out of the gate strong. Number one, your brain can physically rewire itself. Even if it's injured, even if entire parts of your brain are removed, you might have heard of the term neuroplasticity. And this is exactly what we're talking about here. A very good definition, probably the

3:13 best definition of neuroplasticity I've come across is basically it is the ability for your nervous system, including your brain, to change its activity in response to intrinsic, and extrinsic stimuli by reorganizing its structures, its functions, its connections. In other words, our brain can adapt due to experience. This is what allows us to learn new skills, to recover after strokes or traumatic brain injuries, and also to change our deep ways of being and our thought patterns and our habits. If we didn't have neuroplasticity, we wouldn't be capable of any kind of personal evolution. We wouldn't be capable of any kind of adaptation. This is our brain's first superpower. Our brain is very good at working out

3:57 what we need and what we don't need. It's a bit of an efficiency machine at its core. And this is how it carries out that efficiency plan through neuroplasticity.

4:08 The thing is, we.

4:09 Didn't really know the neural basis of this until probably 60 years ago or so. Our brains are composed of around a hundred billion, billion with a B, neurons, and Early researchers really thought that, you know, that kind of creation of new neurons stopped shortly after birth. And we now know that is not true and that throughout our lives we can reorganize pathways, we can create new connections, and in some cases we can even create new neurons, especially in our late teens and in our 20s. Now, there are two main types of neuroplasticity. that are very important for you to know if you want to change anything about who you are as a person. Firstly is functional plasticity. This is the brain's ability to move functions

5:01 from a damaged area of the brain to another undamaged area. This is mainly in response to things like trauma, but I mean physical trauma. It is the equivalent of riding your bike around a pothole to avoid falling in. And this happens in three ways. So functional neuroplasticity has three ways of operating. Neuronal unmasking, so basically the brain opens up dormant or backup synapses that were previously inactive to take over damaged tissue nearby. Axonal sprouting, undamaged neurons grow new nerve endings known as axons to reconnect with other pathways and to build kind of lost networks. This is like the part of you that comes in and builds bridges that were, I guess, bombed. And then there's neural

5:50 network adaptation. Neighboring healthy regions become more engaged and take on new roles. So we have reinforcements, bridge building, and then regional relocating. I genuinely cannot explain how amazing it is that your brain can do that. I feel like I'm going to use the word miracle so many times, but it is almost miraculous that We have this entire task force of neurons dedicated to helping us survive really awful things, damaging things, and to still function. Now, the second way neuroplasticity takes place is through something called structural plasticity.

6:29 Structural plasticity is the brain's ability to actually change its physical structure as a result of learning. And I don't just mean sitting down with a textbook learning, but learning through everyday life. instead of just kind of changing the strength of existing signals or, you know, moving things around, it can physically alter its chemical and cellular makeup so that it looks physically different. Certain areas of our brain can gain more volume and become more dense. And you can see this on brain imaging scans. The more you learn or train or mentally challenge yourself, the more gray matter you may get. And this is something that you can really do for most of your life. That does kind of become a tipping point, but most of your life,

7:15 you get the density of your brain. There are some limits to neuroplasticity. For example, certain areas of your brain that are responsible for very specific actions can't be moved. So if the part of your brain that is responsible for language is severely damaged, this can't always be converted. Or part of your brain that's responsible for converting short-term to long-term memory is damaged. Again, it's not like we can rewire that completely. But in general, at nearly any stage of your life, you can influence the flexibility of your brain, your neural networks, perhaps even the very structure of your brain through learning and through your actions and also through your thoughts and what you practice telling yourself

8:00 or what you practice striving for or just doing. I think we believe that at some stage, We just are the person we are and nothing's going to change about that. This is just who I always am going to be. And neuroplasticity disproves this entirely. Your brain remains plastic for your entire life, pretty much, especially if you give it the certain conditions under which to do so. So I want to talk about some very simple science-backed ways to actually promote neuroplasticity if you want to keep your brain in this malleable state. The very first one being learning.

8:38 If you want to keep your brain plastic and malleable and flexible, learning should be a lifelong pursuit. And not just, as I said, in an academic sense, in a school sense, but in a private sense as well. Learning a new language, getting back to crafting or making art, you know, reading instead of doom scrolling, learning how to do things with your hands, learning new skills, they all count. Your brain remains flexible as long as you give it a reason to do so. As long as you say there's a reason that we want you to be this way, because we are going to give you new information. We are going to give you new skills. So giving it learning material basically is a way to do that. The second way to maintain neuroplasticity is to play more. I think

9:23 we look down at people who are a little bit silly, but having fun is one of the most neurologically powerful things that you can do for your brain health. There was one very important 2014 paper that published in the Journal of Brain Imaging and Behavior, and it found that people who maintain their playfulness into adulthood, so people who play cards, who play outside, who play with their pets, play with their friends, they had significantly higher gray matter volume than people who did not do these things. They also minimized their Alzheimer's risk, they minimized physical health risks.

10:01 They didn't really have to do anything else. It wasn't like it was this arduous task. They just had to have fun. That is so important for your brain health and your neuroplasticity, actually enjoying yourself and being playful. The third way to maintain neuroplasticity, be very careful about how you speak to yourself. You are the first point of contact between your brain and the world around you. So if you say to yourself, you know, that's not possible for someone like me, or the world is just really against me. If you say that enough times, just you thinking that is the only evidence your brain actually needs to believe it and to make a pathway directly to that way of seeing things. Just watch how quickly those

10:45 thoughts now become your reality. Because your brain refuses to search for anything different. If you have fed it this information, if you have said this is how the world is, of course it's going to believe you. Of course it's going to trust you. So be very careful with how you speak to yourself. And finally, and very similar to my above point, I think just know that your brain is malleable. Just know that your brain is flexible. That alone helps with neuroplasticity. An example of this is a study that was done in the U.S., over a two-year period on teenagers. And it looked at how beliefs about learning could have an impact upon achievement, especially in math.

11:24 And the study found that teenagers who were taught that their brain was malleable, their intelligence was malleable, their intellect was malleable, that they could make themselves smarter, basically, just being taught that and nothing else significantly meant that they were going to outperform those who weren't taught this. Basically, they did better Because they believed that they could and because they understood that their brain was not fixed. So neuroplasticity, it works in our favor. It's also a powerful weapon in both directions. You have to remember whatever you feed your brain regularly in terms of thoughts, behaviors, actions, it is built to respond to that. It is flexible to your way of seeing the world. And those ways of

12:06 thinking will become your default. Now that you know about it, hopefully you can control it. So brain fact number two. Your brain feels pain, not the body, which is why emotional pain can feel just as awful as the physical kind. We have this belief that physical pain and mental pain are pretty much distinct. They're separate. And we also have this belief that one is worse than the other. Breaking a leg is worse than a broken heart. But psychology is increasingly demonstrating the opposite of that. When people feel emotional pain, the same areas of the brain get activated as when people feel a physical hurt. In one study, actually, they had all these researchers, they created a situation of what we call experimental social rejection. So basically, they made

13:00 it seem like people in this experiment were being rejected by real humans. And the way they did that was they got people to play a virtual ball game, and they would toss the ball between them and these other virtual people who they were told were real people. And then at some stage in the game, nobody would toss to them anymore. And whilst this was happening, they hooked them up to brain imaging devices just to see how their brain was responding to this social rejection and this sense of being outcast. What scans showed is that the areas of the brain that light up when physical pain is experienced, specifically the anterior insula and the anterior cingulate, anterior cingulate cortex, actually to be specific, those regions were

13:41 also activated in what seemed like very benign and definitely not physically painful scenarios. It's not physically painful to be rejected, but we still feel it on a deeper level because of this neural representation of pain. Another study took this a step further and it looked at people's brains in conditions of real social rejection. So not experimental social rejection, but real life. And the way they did that was they showed participants pictures of former romantic partners who had broken up with them. Very cruel how they got access to these pictures as well. A little bit, I don't really know how they did, but they did. And again, they put them up, they attached them to a brain imaging scan and the same regions of the brain were

14:23 activated as physical pain activates as well. Basically, emotional, social, physical pain, all of them share what we call somatosensory representation. They are mapped to these same region. If we want to take this even a step further, there have been certain experiments that have shown that just taking drugs that are normally associated with reducing physical pain, so ibuprofen, Advil, aspirin, Panadol, I don't know what you guys all call them, but Panadol, that kind of thing, just taking those can have an impact on how emotional pain is received or perceived as well.

15:01 So in one study in 2010 by researchers in the UK, people who had experienced a recent social rejection were randomly assigned to take paracetamol versus a placebo every day for three weeks. The people who took the drug reported fewer basically hurt feelings. So this was a randomly controlled study. When their brains were scanned at the very end of the treatment period, we would call it, the people who had taken paracetamol had less activation in that anterior insular and anterior cegullate cortex. A lot of our brain's perception of pain is very emotional, and it's closely linked to our mental health as well. This is why many people notice improvements in their perception of pain when they sleep better,

15:51 when they reduce stress, when they increase social connection, or when they get professional help. It's also why people whose pain is repeatedly dismissed by healthcare professionals will notice their pain getting worse for a couple of reasons. A, because their symptoms aren't being addressed or treated, but also because their mind feels rejected and less capable of dealing with this pain because they are being dismissed. The social dismissal and social rejection effects are impacting the same region where the chronic pain is also being experienced as well. And so you have this cumulative load of painful experiences making each one worse. Everything is connected. We have to stop treating health like it's these distinct pillars that need to

16:37 be addressed one by one, you know, mental health first, then physical health, then social health. We have to stop treating physical pain like it's more serious than mental pain. And unless you have a wound or a scar, like you really need to get over it. All of it is interrelated and interconnected and comes down to how your brain is operating. Okay, we're going to take a short break here. And then when we return, I want to talk about movies, specifically what movies get wrong about the brain.

17:07 Stay with us.

17:13 So I said we were going to talk about movies. We're actually going to talk about two in particular. The first one is Lucy, the movie Lucy. I watched this a couple of nights ago with my boyfriend and to jog your memory, I think it came out in like 2014, 2013. with Scarlett Johansson and Morgan Freeman. And in the movie, Scarlett Johansson, she gets like drugged with this drug that causes her to use more than 10% of her brain.

17:42 And she suddenly becomes this superhuman. And it's basically the exact same movie as, or the movie plot as the movie Limitless with Bradley Cooper. Literally same thing. Bradley takes a drug that allows him to use 100% of his brain. He becomes very smart, blah, blah, blah. When I say these are the same movie, they are basically, I genuinely think that like the script was accidentally dropped off at two of the same offices at the same time. So if you've watched one, you've probably watched the other. But these two movies are very critical because it was these movies that popularized the idea that we only use a small section of our brain, 10% to be specific. Now, this theory didn't begin in Hollywood. It was popularized in Hollywood,

18:23 but it began with two Harvard psychologists. Their names were William James and Boris Sidis. And they first wrote about this theory in this big paper that they released in the 1890s. And they said, guess what? We only use 10% of our brain. If you were going to ask what scientific evidence they had for that, they basically didn't have any.

18:42 They didn't have any. But they had a theory. They said, you know, humans don't use everything, all the flesh in their head. And their theory also said that the first person who could use 100% of their brain would be this mega genius. And an interesting part of this story is that they then went on, well, Boris went on to try and raise his son this way. He tried to raise his son to be a super genius, to use 100% of his brain. I feel like we all know how that turned out. This guy, this kid really, he went to Harvard when he was 11. He wrote all these books. And then basically he fell off the face of the earth and had a terrible mental health crisis and was never seen again. But when this big theory was going around and when it was first released

19:25 in the 1890s and the early 1900s, People loved it. People loved this idea that we could all be secret geniuses if we just took a pill or used 100% of our brain. And it created a lot of these, what our modern day equivalent would be clickbait articles and newspapers. And it became very popular and then forgotten. And then there was a resurgence of the idea with those movies, Limitless.

19:50 and Lucy. Is that true? Do we only use 10% of our brain? No. The actual truth is that we use all of our brain, all of it. Even if not all neurons are firing at the same time, we use all of our brain. This became quite glaringly obvious with the invention of the MRI machine, which basically showed that there is widespread ongoing activity in most of the brain at any given time. Even when we're asleep, we are using more than 10% of our brain. What's more, our brain only accounts for 2% of our body mass, but about 20% of our energy consumption. In infants specifically, the brain uses about 60% of our everyday caloric intake. Now, from an evolutionary perspective, there is just no way that such an energy costly organ could be so underused that

20:43 we would only require 10% of it at any given time. Humans would never have evolved to have brains anywhere near the size that we do if we didn't use every single part of it. I think anytime you see a statement or a finding that simplifies things so perfectly and without any exceptions, you can tell it's false. 10%. is just too specific of a number. And for it to apply to absolutely every single person without any considerations or without any, you know, kind of second guess, without any caveats is just ridiculous. So you use way more than 10% of your brain. You use every single part of it.

21:25 Anybody who tries to tell you otherwise has probably gotten that information from a Hollywood blockbuster. Fact number four, your brain and your stomach are deeply deeply linked. There is a known two-way communication pathway between your gut and your brain and it's known as the gut-brain axis. This connection is physical. It connects to the vagus nerve and it's chemical as well via neurotransmitters. They are in constant communication and This is part of the reason why our gut, I don't know if you've heard it referred to this, is sometimes called the second brain. Scientists also call it the enteric nervous system or ENS for short. The ENS, as opposed to the CNS, central nervous system, is actually

22:16 just two thin layers of more than 100 million nerve cells that line your gastrointestinal tract. Now, the main role of the ENS is controlling digestion from from swallowing and through the release of enzymes so that we can break down our food, so that we can get energy, so that we can control blood flow, blood sugar, all that kind of stuff, and so that we can absorb and eliminate nutrients. It also plays a secondary role, which is it impacts our mood. For example, our gut microbiome, so the microbes living in your gut right now, produce up to 95% of our serotonin. Serotonin, as we know it, is the happy chemical. That's its colloquial name. Now this serotonin can't necessarily cross the blood-brain barrier, but it does

23:05 assist with things like gut immunity, which therefore influences what energy you receive from food, the level of inflammation in your stomach, and the level of toxicity as well. And also things like irritability, things like perception of pain, once again, so many things. One 2023 study published in the journal Nature, which is a favorite on the podcast, even suggests that this relationship between gut health and overall happiness is the reason why people with IBS or other stomach issues are significantly more likely to suffer from depression and anxiety. Now, previously, scientists kind of thought, or doctors as well, thought that people who were anxious and depressed were more likely to develop IBS-like symptoms, you know, like an upset stomach, like pain,

23:53 like bloating, because of emotional distress, because they were so upset that this was putting stress on their stomach, it's increasingly understood that it may be the other way around and that IBS may be essentially an over-communication between the gut and the brain. The symptoms that IBS creates like constipation, bloating, pain, stomach upset, contribute to people feeling not as mentally stable healthy, feeling depressed and anxious because the irritated gastrointestinal system sends all these signals to the central nervous system that something is wrong and that triggers mood changes. Doctors treating IBS may actually even at times prescribe certain antidepressants for this very reason, to calm symptoms by acting on nerve cells

24:45 in the gut and also by acting on that communication pathway or channel. Our gut also has a surprising role I think I mentioned before, in how we perceive pain. When the gut microbiome is imbalanced, inflamed, disrupted by stress, the gut-brain access is once again negatively impacted. In particular, the brain's ability to process certain sensations properly, sustainably, effectively is affected. And studies have shown that gut inflammation increases sensitivity to pain, also heightens anxiety, which increases perception of pain, Alternatively, a healthy microbiome can support emotional regulation and also reduce pain intensity. So this means that food, stress, sleep, infections, even antibiotics, drinking alcohol can alter how your brain senses

25:37 the world around you, not just through your mind, but through your gut.

25:41 The biggest way.

25:42 That I've noticed this, and this is going to sound so strange, and maybe there's a doctor listening to this who's going to be like, you have nothing, this is ridiculous. but it's gum. It's chewing gum. I used to chew so much gum, I really cannot make it up. My stomach would be so sore, so bloated, so upset. And since stopping, I feel like I'm so much less irritable.

26:05 My mental health has gotten better. Day to day, I'm much more patient. Now this could be utterly ridiculous. It could be utterly unrelated. But the more I learn about this second brain, the more I do believe it. Especially last year, I was eating things, chewing things, drinking things, It definitely didn't make my stomach feel good and then definitely didn't make my brain feel good either. I don't think you thought I was going to be talking about stomach pains and diarrhea and upset stomachs in this episode.

26:33 But yes, it does really, really impact and is directly related to how your brain operates. Okay, moving on. Moving on from that to fact number five. And one we spoke about in an episode just a few weeks back. but which deserves its place on this list, I think nonetheless. Your brain actually can't multitask. It cannot multitask, at least not effectively, no matter what you believe. Lots of us like to think that we are able to kind of do two things at once fairly seamlessly. There's an old stereotype that women in particular are very good at multitasking.

27:16 Unfortunately for us, a very, very famous study came out in 2013 that essentially said, sorry, that's not true. You're always sacrificing something. This study was done at the University of Utah by a man named David Sanbon Matsu, who is a professor of social psychology. And he's basically spent his entire career as a social psychologist and researcher looking into attention and His name will come up a couple of times whenever you're looking at attention research. But for this study, this is what he did. He recruited 300 undergraduate students. He had them do a questionnaire where he basically asked them, you know, how often do you use your cell phone when you're driving? Do you think that when you use your cell phone and you're driving, it

28:02 impacts your driving? How well do you think you are at multitasking? How impulsive are you? How good are you at driving just in general? What about your motor skills? And then he tested them. He tested them on their abilities to multitask or drive whilst being on their phone with an automated computer task. Part of the computer task had subjects trying not to crash in a driving simulation whilst performing memory tasks and analyzing math problems. And this computer task he had them do is actually a task that's used quite frequently in multitasking research. Participants are shown a sequence of letters. And if you've been a psych student and you've done psych studies, you may have done this before. you see a sequence of letters and then

28:46 in between those sequence of letters, you're asked to memorize them and then you're asked to do math problems. And then you do the math problem and then they say, what were the letters you saw before this? You can't remember. Sometimes you can and then you're given a score. What he found was A, the majority of these people were very overconfident about their multitasking ability. B, the majority of people were actually very bad at multitasking. But also, and this was the most surprising finding of all, the people who multitasked the most were the worst at it. The people who multitasked the least were the best at it.

29:27 Like the people who were the best at multitasking, who could actually really had a knack for it, rarely did it. His study found that those rare individuals, the good multitaskers, they accounted for about 2%. of all participants. So when he went back and he said to his students or to the participants, okay, there's people who are good at multitasking, that's about 2%, and there's people who are bad, which group do you think you're a part of? 93% of them said, well, of course, I'm in the really good group. Now, considering that group only represented 2% of people, a lot of them are wrong. A lot more research supports the fact that multitasking actually results in a cognitive cost to our brain. When we shift between tasks, our prefrontal cortex

30:13 rapidly shifts attention, our working memory becomes overloaded, and this makes tasks take way longer than we anticipate. The thing is, You might think you're a good multitasker and I certainly did because you don't really realize it until it's too late and also because we confuse the novelty that comes with task switching with progress. We're doing all these things, something different, something different, something different and that feels like progress.

30:40 It's actually just distraction. This is why I think this fact belongs on this list. Whether it is driving or you're at work or you're studying, whatever it is, when you multitask, you are forcing your brain to to operate in a way that it doesn't naturally want to. It can do it. It can, but it doesn't really want to.

31:02 I saw somebody say that multitasking is for emergencies or nothing tasks, but very little in between. And I think I would have to agree. And I think you should too, knowing what we now know about how our brain is actually operating in these situations. Okay, I think we need to take one more break. But when we return, I have two more and two final essential learnings for you about your brain that I want to talk about.

31:25 So stay with us.

31:33 So this just might be one of the most crucial, perhaps the most important insights from this entire episode, especially for my 20-somethings, which I'm going to assume is the majority of you given the name of this podcast. Despite what you may have heard, your brain does not Stop developing at 25. Your frontal lobe does not fully develop at that age and no other age. Your mid-20s are not a death sentence for your brain development. It actually takes a long time for your brain to fully lock into place. And your brain development is very much a lifelong progress that has many iterations, many leaps, many different stages.

32:14 So this idea of your frontal lobe kind of locking into place right at the point you turn 25 is I think it's a bit of a running joke. We use it for all kinds of things, all kinds of excuses and justifications for like messy early twenties behavior. And the reason it is so convincing is because I think we kind of feel it. Like we do kind of feel that our reasoning skills improve as we get older.

32:40 And we certainly sense, we sense ourselves maturing and making better decisions around like our mid to late twenties. So anecdotally, We're kind of like, yeah, I see some evidence for this. I feel like my brain developed at 25. I feel it developing around this time. The other reason why I think that it feels so compelling is because this myth actually did originate from some very real scientific research that just ended up being deeply misinterpreted. So people might be able to cite studies for you. Are they reading those studies?

33:10 Probably not. This idea specifically came from a series of brain imaging research papers that released in the 1990s and early 2000s. And it also came from the words of one man in particular and what he said. But before we get to what he said, let's look at this research. So in the late 1990s, scientists and researchers were trying to answer a very, very serious question, which is when do people become emotionally responsible for their actions based on brain development? They were Specifically, they were trying to look at this in the context of criminality and the death penalty.

33:52 Is it fair to sentence an 18-year-old to death or a 20-year-old, but not someone who is 16 or 17, if their brain development might actually be at an identical, if not very similar level? When should people feel and be responsible for their actions based on brain development? To answer this question, they basically had to know when does the brain fully mature and specifically the frontal lobe, which is the last part of the brain to reach maturity.

34:19 So starting in 1999, they tracked these participants and they tracked their brain changes through repeated MRI scans on people when they were children, when they were teenagers, and then when they were adults. This was a longitudinal study, so they kept the same participants all the way through to see if there was a lot of individual variation, what the kind of standard deviation, the median was. And they discovered that during the teenage years, gray matter goes through a process called pruning. It's a lot like pruning a tree, to be honest, hence probably why they use that word.

34:54 But early in life, the brain builds an enormous, enormous number of neural connections. We know this is neurogenesis. We spoke about it before. And as we age, it doesn't need all those connections. So it gradually trims back the ones that are not really used and it strengthens those that remain. And they discovered that more primal regions like areas responsible for muscle movement, for fear, for learning, they develop first and they're pruned first, whilst more advanced regions that are important for emotional regulation, for decision-making, for social cues and social behavior, they had not fully matured by the time participants exited the study and had their final brain scan at 20. And this is the crucial thing.

35:48 The study, the big study that said your brain develops at 25, it actually stopped at 20. The oldest participant was 20. There were no brain scans for anyone above that age. So where did we get 25 from? Where did this number appear? Well, the man who conducted this research, he obviously did a bit of a press tour around this, He did an interview with Time magazine about five years after the first study was published. And the researcher asked him, you know, well, in your research, by the end, some of these kids' brains hadn't fully developed and they were 20.

36:25 So when do you think our brain is fully developed? And he thought about it and he speculated a little bit and he said, well, you know, if I had to pick a number, I'd probably go with 25. And it was that interview that that created this myth that your frontal lobe develops at 25. So what's the truth? The truth is, is that neuroscience has evolved considerably since those early studies. And instead of looking at individual regions in isolation or trying to create a general idea, scientists now study how efficiently different parts of the brain communicate with each other across all ages. And more specifically, across different periods. It's not like there's a single year. It sees it as kind of these rolling chapters. And a

37:13 very recent study, it's now quite famous, it was only conducted in 2025, looked at specifically this thing called topological turning points across the human lifespan. This study involved scans from over 4,000 people, from infants to people who were 90. And it wanted to understand how is it wired through white matter across the course of your life? the researchers discovered that there are several key periods of development. So the first one lasts until we're about nine, and then the second one is between the ages of nine and 32.

37:48 And they call this the adolescent period. During adolescence, and I know it sounds strange to think of our 30s or even our 20s as adolescence, but during adolescence, the brain balances two key processes known as segregation and integration. Segregation in a brain sense involves building lots of villages or related thoughts. Integration involves building roads to connect those villages to each other. The research suggests this construction of little villages and the roads that run between them doesn't really stabilize into an adult pattern until about your early 30s.

38:24 So that brain building, your brain building site is still very much active in your 20s. Now after 32, around that time, the brain starts to really formalize pathways and really build almost like neural fences around different areas. And this is when personality and intelligence tend to plateau, not completely, but just plateau. And then the next turning point doesn't really happen until about 66 and it's much milder and it isn't really defined by as many major structural shifts.

38:53 And then after that, we have another turning point in our eighties. In other words, Your teens and 20s are spent connecting the brain. Your 30s are about settling down and maintaining your most used roots. And up until about 60, everything kind of seems to operate kind of at the same level. Like we still have neuroplasticity going on. We can still learn, but things kind of settle. But if you are in your 20s and you are worried that the habits you have right now, the person you are right now is rigid, unchangeable, you don't want to be this person, but you're incapable of ever being anything different, That is not correct. There is so much scope for change and there is so much ability to set yourself

39:34 up mentally and physically and neurologically for an expansive life. Even in your early thirties, even up until later adulthood, your brain remains flexible and The neural village is always buzzing, always active. Our brain is constantly evolving, constantly shifting, constantly moving to be at its best, which we know from earlier facts also is what promotes neuroplasticity. So there you go.

39:58 There is no magical switch. If you are like approaching 25 or just past 25 and you're like, cool, that's it. That chapter is done. No, you are a decades long building project and you have a lot maybe saying you have a long ways to go isn't like particularly helpful. I think it is. You're not locked in place if you have passed this milestone. And if you are before this milestone, you still have a long way ahead to change your life and change your neural patterns and change your behavioral patterns as well. So this leaves us with one final brain fact for this episode. And you know what?

40:36 It's not the most glamorous. It's actually not, it's not the most sexy. Maybe it's not the most interesting, but I think it's something that I think it's the one we think about the least and we talk about the least as well. And that is the role of forgetting. I know, ironic that it's probably the most forgetful, like forgettable brain fact. And it's about forgetting. But your brain needs to forget in order to function. It is not a flaw. It is not a mistake. It is crucial.

41:03 Until recently, I think we thought of forgetfulness or the loss of memories or details as as a passive process or a bad process. And we didn't want to do that. We didn't want to forget. Now we know differently. There's this man, his name is Scott Small. He's the director of the Alzheimer's Disease Research Center at Columbia University. And he wrote this book about five years ago called, great title by the way, Forgetting the Benefits of Not Remembering.

41:30 And in this book, the main message was basically that for most people, your ability to not remember What exactly you ate three weeks ago or even this morning or that random person's name, your ability to kind of forget about the plot of the movie you saw a couple weeks ago, maybe a year ago, or every unremarkable thing that you've seen is remarkably important and ensures that your brain and you as a person not just survives but flourishes mentally. Studies have shown that there seems to be a specific molecule that within our neurons that wants them to forget, wants to clear up space for more important things to come along long-term. And basically like this protein, this molecule has like the personality of like Marie Kondo.

42:19 Like this protein is a bit of a minimalist and it's kind of going through the brain house and being like, what's important, what's not, anything that's not completely crucial, let's get rid of it because more stuff is going to be coming through soon. Now this molecule is called the Musashi protein. And it's responsible for the structure and the function of our synaptic connections. It's responsible for ensuring that there are clear pathways and that only the most important stuff is communicated. Now this protein has a partner in crime and together, I don't even know if partner in crime is the right word, maybe like a bit of an arch nemesis, but they work together kind of, they're partially responsible for two parallel mechanisms. One of them stimulates

43:03 the growth of synapses and therefore helps to retain important memories and wants everything to be remembered. And then the Musashi protein comes in and actively inhibits the stabilization of these synapses, allowing memories to be lost. And it is the balance between these two proteins, which is so crucial for the retention of memories and some of the most important memories that we have. Our world is buzzing with information.

43:31 There's so much going on all the time and our brain needs to be able to discard the useless stuff so that our ability to learn and so that our ability to generate new ideas isn't interrupted. And this is really, really crucial. Now, there is also such a thing as not being able to forget enough. Traumatic experiences, conditions like PTSD, make it a lot harder for us as humans to let go of certain memories that feel important because they are painful. And that means that these memories become embedded in our mind, hurt us, impede our ability to recover mentally.

44:10 PTSD can cause too much emotional memory. It's kind of like a brain on fire disorder, which is also characteristic of other psychiatric conditions. You know, obsessive compulsive disorder, anxiety disorders, phobias. They have this kind of brain on fire mentality where there's just so much information we're trying to remember and sort through. and all of it feels scary. There was a really interesting paper published in 2024, which was conducted on rats. And in this research, researchers suppressed the production of the protein needed to stabilize memory, and they artificially increased the production of the Musashi protein, which is required to forget. And then they put these rats into very traumatic circumstances, where they experienced pain, and they experienced bad things.

44:59 And they found that those rats who had undergone this intervention to increase forgetfulness, minimize remembering, experienced less PTSD, less long-term fear, and disrupted the formation of traumatic memories. This is such an interesting line of research that is currently ongoing in kind of the trauma space because it basically shows the neural underpinnings of painful memories and why we can't seem to let them go, even when we really want to. But it also opens up all these future possibilities for new treatments and new drugs and new methods for helping people properly process really difficult things, you know, in the wake of natural disasters, in the wake of war or genocide. Not that we want this to go

45:46 too far. We have to be careful here. I feel like this could be misused very easily, could be capitalized on. in many ways, or we could end up with kind of an eternal sunshine on the spotless mind situation. Another great movie, by the way. Actually, probably the first great movie we've mentioned in this episode, but a great movie.

46:04 But for people who have tried everything, for people who have what we call treatment-resistant PTSD or depression, I think these findings offer a bit of a miracle in a way. So much about the brain is miraculous. It's just incredible that we could assist people with forgetting some of the worst times in their life or at least reducing the emotional intensity of them. And again, there's that word miracle.

46:29 And I feel like the more you learn about the brain and how everything is kind of constructed and built in this way to protect you and to allow you to have a human experience, it's just honestly mind-blowing. It's so mind-blowing that not even for a second, I think, do most of us think about this on a day-to-day basis?

46:50 Like you and I are not tasting food or experiencing heartbreak or forgetting where our keys are and thinking about massage proteins or synapses or neural priming or whatever, but it's going on and it's keeping us alive and it's doing all these amazing things for us. And if we can use that to our advantage, like that is incredible.

47:10 It also shows how so much of like the supposed flaws in our brain are Just show an incredible science. Forgetting is incredible. Pain and how it relates to all these different parts of your body, to the gut, to the mind, to your pain receptors is incredible. How strongly you feel about heartbreak is incredible. The fact that we can focus is incredible. I feel like I'm just going over and over this, but it all comes down to this incredible science and the incredible neural information that your brain stores. And I think there is something incredibly humbling about that. We spend so much of our lives wishing our brains were different, comparing our brains to how somebody else's brain works, thinking they're more smart, they're more creative,

47:57 they're calmer, they're more resilient. And we don't really stop to appreciate the staggering amount of work that our mind and our brain does every single day just to keep us here and just to keep us alive and functioning, but also to our conscious role in that as well. You have a bit of a say here. You can influence how your brain is wired and structured through neuroplasticity, through how you speak to yourself, through the information you choose to feed it and the behaviors you choose to enact.

48:26 So that is our episode today. That is all of our brain facts. I sincerely hope you enjoyed it. I hope that your brain maybe feels more dense and connected as a result. Hopefully it feels more plastic. Yeah, I just hope you learned something. If you want to keep up to date with new episodes of the podcast, including more science-based episodes like this one, make sure that you are subscribed or you are following along wherever you are listening and that you're also following us over on Instagram or Substack because we share so much more psychology and science and research content over there and we make sure it's all accessible. So if you've ever had any questions about how your mind works, why you feel the way

49:07 you feel, why you do the things you do, that's a great place to learn. Thank you to our researcher Lucy Davidson for her help with this episode. And if you have made it this far, leave a little brain emoji down below if you are listening on Spotify so that I know. you've got a great attention span you made it all the way to the end until next time be safe be kind be gentle to yourself and look after that brain of yours we will talk very very soon