in today's video with the help of the cadavers here in the lab we're going to see two of the most fascinating things that happen to your brain when you're sleeping which then obviously means we'll also understand what's not happening to your brain when you are not sleeping it's going to be an enlightening one let's do this [Music] it's widely known that there isn't a broadly defined consensus among researchers as to the purpose of sleep but that doesn't mean that we have no idea at all why we sleep in fact quite a bit is known about the different physiological processes that occur during sleep as well as the different stages of sleep so in today's video i've decided to talk about the two that i personally find to be the most interesting but there are plenty of others that we could be equally nerding out on first off we're going to start with what's called the glymphatic system which you could think of as the brain's overnight custodial service during the course of the day your brain just as every other organ and tissue in your body produces metabolic waste as a consequence of just normal functioning for pretty much everywhere else except the brain the lymphatic system is mostly responsible for performing that metabolic cleanup but to the surprise of probably no one the brain has its own specialized system for this cleanup and it doesn't quite qualify as being the typical lymphatic system so to best understand what's again known as the glymphatic system which is just a combination of the terms glial and lymphatic we first need to understand how the brain produces cerebrospinal fluid you are looking at the right hemisphere of the human brain as seen from a medial or midline view now i want to give you a brief tour of what you're looking at here because there's a ton to focus on but we actually want to focus on these hollow spaces you see where i'm just sticking my probe into the brain this is what's called a lateral ventricle now there are actually two lateral ventricles one in each hemisphere but considering i'm only holding one hemisphere you can only see one lateral ventricle and then in this space right here it doesn't really this i don't know if this is going to come across that well but if we had both hemispheres together there would be a hollow space in this area which we would call the third ventricle and then you can also see there's like this triangular space between the cerebellum and then the brain stem this is the fourth ventricle now ventricle just means or is referring to a hollow space inside of the brain and what's produced there is cerebrospinal fluid or csf for short and what it's going to do is it's going to flow from the lateral and third ventricles and fourth ventricles and eventually it's going to actually make its way outside of the brain and then it's going to surround and bathe the brain now in mammals and yes you are a mammal around 10 percent of the total fluid volume inside of the cranial cavity is csf now that 10 is actually replaced over the course of the day around four different times and many more times in some other mammals and this entire process is highly regulated because if you have too much or too little csf that can have some dire consequences on the brain now as i just said one of the functions of csf is to literally bathe the brain it's going to be flowing in a space just above it and then it's going to start making its way into the actual brain tissue and for years we assumed that this process was more or less random like the fluid just went into the brain tissue and then again randomly made its way back out of the tissue and into the venous system however in 2012 researchers discovered that while yes the randomness does still occur there are also other times that instead the csf very purposefully and quickly penetrates deep into the brain tissue and then again very purposefully and quickly exits the brain tissue now what's really cool about this is that during this process of csf quickly going into the brain tissue and then quickly and efficiently exiting metabolic waste is cleared out with it this process which involves the cells and structures responsible for facilitating this movement is the glymphatic system and it answers an age-old question about how does the brain efficiently clear out metabolic waste despite not having your typical lymphatic system but if that wasn't cool enough this glymphatic system is almost exclusively active at night when you're sleeping this means that when you don't get enough or really any at all sleep there is a literal traffic jam of metabolites on and inside of your brain desperately hoping that you're going to get some shut eye so csf can come in there bathe it flush it out leaving you refreshed and spry in the morning so if this sounds like you it might be time for you to start thinking about making some serious changes to your health and sleep habits that's why i love the sponsor of today's video noom i've been using noom for a little over six months now and i am head over heels for it and the reason is super simple it's not your run-of-the-mill fitness tracker i mean sure yes it does track your your calories your steps your weight but it does so much more than that it educates you on why tracking those in the first place is a good idea and it does that through daily lessons and articles which are super short by the way it'll take you 10 minutes or less to make your way through them with nume you have a goal specialist that's trained in psychology nutrition and fitness to help guide you through this educational journey newm is special because they're doing the only thing that i've ever seen work with people long-term building better habits sleep habits eating habits fitness habits and they do all of it without shaming you for missing a weigh-in or not reading all of your daily articles instead your goal specialist will check in with you and see how you're doing and what they can do to help you out now for me personally i love ice cream it's something i'm not ashamed of but that love can get pretty intense at times which is why i decided to reach out to my goal specialist and see if we could come up with some kind of solution that allowed me to still eat ice cream because that's not going to stop but not to do it with reckless abandon like i really want to and it was great we were able to come up with something that works for me and i still get to satisfy those cravings it's been fantastic to have them on my side so if you're interested go ahead and click the link in the description below or just visit noom.com humanatomy and take your free new evaluation today it's quick it's easy and it's the first step to building better health habits all right let's get back to it anyone that's ever started a new job or tried to sue the colicky baby at 3 a.m or maybe just studied late into the evening for a final exam the next day can tell you that operating at full efficiency with little to no sleep is basically impossible right little errors will start to accumulate before you know it you can't put your shoes on properly and for some reason you're calling your new boss jack despite his name definitely being jim now to see why this is we need to discuss an extremely important structure of the brain called the hippocampus now unfortunately you can't see the hippocampus in this particular brain dissection because it's going to be deep to this area of the brain called the temporal lobe but the hippocampus belongs to another system of the brain called the limbic system and the limbic system is an extremely old part of the brain at least old evolutionarily speaking and does a wide variety of things that we'll definitely discuss in many future videos to come but the exact functions of the hippocampus are still somewhat unclear but most researchers would agree that it plays an essential and vital role in converting or consolidating short-term memories into long-term memories memory is extremely complex and it's a topic that we're going to need to tackle in a future video on its own just to give it the justice it deserves but very very very generally speaking you can think of short-term memory as being the events and emotions that have happened to you moment by moment and then long-term memory is going to be the events and emotions that happen to you over days weeks months and even years to come now most short-term memories are not overly useful to us in the long term so they simply just fade away as the day goes on now i often do this experiment with my students to prove or show this point i want you to think back to what you ate for dinner last night right can you remember what you had at all okay how about can you remember where the different uh parts of your dinner were on your plate can you remember what order you ate them in can you remember how many bites it took you to actually eat the whole thing let's say you had peas for instance do you remember how many peas were on your plate right we can go on and on with this it goes to show you that honestly most short-term memories are just not that useful so the brain has no problem just getting rid of them when appropriate the thing is it's the job of the hippocampus to consolidate that information and actually turn it into a long-term memory that is useful to us such as did you enjoy the meal at all now this might be a pretty big oversimplification but i really do feel that it helps serve the larger point here the fact is sleep is vital for this process when you sleep at night memory consolidation improves and studies have shown that well-rested individuals routinely outperform their sleep-deprived counterparts this just goes to show that getting a full night's rest doesn't just clear out that metabolic mess you made during the day it helps convert your daily experiences and all that new information you learn that day into long-term memories that you can utilize at a later date it's completely ironic that all those university students that are just staying up all night studying for that extremely important exam that's gonna happen the next morning they're more likely to get worse grades and perform worse on it than if they just gotten a full night's sleep just get that sleep people thanks for watching everybody be sure to click the link in the description below and take your free noom evaluation today if you're like many people out there and you need some better sleep habits noon can definitely help you along that right path as always be sure to like comment subscribe if you feel so inclined and i will see you in the next video [Music] you