Being awake while sleeping, being asleep while awake - Dr Thomas Andrillon

Hello everyone, what a noisy mob. I, Michael Farrell, am the Associate Director here at Monash Biomedical Imaging and today it is my pleasure to introduce Thomas Sir Andrew Lien, who arrived relatively recently here at Monash University, he is in the Faculty of Psychology and not. Only his rival is recent, but he obtained his doctorate in Paris in 2016, yes, so he is a relatively young man and, despite his tender age, he has been extraordinarily productive. He has published a number of articles in magazines under the motto of nature and not only. He is making waves on the scientific front, but is his work in gardening also arousing general interest from the general public?

I'm absolutely delighted that we're hearing about his work today so without further ado I'll hand it over to Thomas thank you thank you all for joining. I have to admit that when you do research on sleep and when you talk about sleep it usually gets a lot of attention because it is something that everyone is easily interested in and it also has some drawbacks. You can't go to a wedding without

being

there or any type of social event without everyone asking them about their sleep disturbances, but it's at least a research topic that connects with people, so what I'll try to present here is actually a recent development in sleep research showing that wakefulness during sleep can offer intermixed offerings.

Therefore, we can often be in a state where we can be both

awake

and

asleep

, but before I start this, since I am a newcomer to both Monash and Australia, I wanted to give a brief biography of myself so that my accent. I tell you I'm French, but I was actually born here, which, surprisingly, maybe to you is French territory and then I sought to spend a lot of my childhood exploring French overseas territories and at some point I decided that my life needed to be. a little more serious, so I went to Paris, like all French people try to do when they want to study, and I started studying biology and cognitive science, so not only did I do my PhD with a scientist who is not

asleep

and is concentrating on absolute. about consciousness and development, so sleep was something new to him and to study sleep and how its impact on cognition and consciousness we partnered with sleep specialists like Daniel DJ and a hearing specialist like Daniel Questions DES and also the opportunity to work in the United States.

States during this period in the lab of Giulio Tononi and Cara Lee and with Shivani, who was a postdoc at the time, now has her own lab in Israel and you will see that a lot of what I am going to present is actually inspired by the work of Giulio Tononi encourages early sleep and the function of sleep mechanisms etc, which is why I graduated with my PhD in 2016, then I took a year off to travel a bit and in 2017 I joined Australia, so I worked no suit Here, here at Monash, biomedical imaging, Gerald Pearson at UNSW and we are collaborating more and more with Chandra, known for the dream aspects of our projects, what is this, now Tahiti, yes, we are friends, I will probably tell you to Haiti as one of its overseas territories, if you have the opportunity, I encourage you to visit them, so why study the dream?

So my interest in sleep was primarily initially because it is a beautiful modulation of consciousness and the way we interact with the environment and in many ways it is puzzling because sleep has been observed in almost all species. animals so far, so it's similar, it's a universal phenomenon in the animal kingdom, it seems necessary, so if you prevent animals from

sleeping

, they die pretty quickly, so if you take humans for example, or others mammals, you die in the same amount. It is time to die of thirst, so

sleeping

is somehow as important as drinking and, despite this, it is still a risky phenomenon, so when we sleep we lose the only advantage of

being

an animal that is lively and capable to respond to their environment.

Why do we put ourselves in such a risky situation every night? So sleep, since for a long time it has been thought to fulfill very important functions where this state of insensitivity will be crucial and that will be the reason why we move between wakefulness. and sleep according to these views, this is almost a direct implication that sleep and wakefulness have to be mutually exclusive because if you can be in states that blend between wakefulness and sleep

while

you sleep and put yourself in a state of total sleep where you cannot interact with your environment, so the problem with that view, meaning the notion that sleep and wakefulness would be mutually exclusive, there is a lot of new evidence and there are many, many data, How will I do it?

The present shows that sleep and wakefulness can actually be intermingled, so it is something that was known in the literature on sleep disorders such as sleepwalking, which can be seen as an abrupt

awake

ning from deep sleep in which the brain knows mixed awake and awake states. sleep activity, but it is also known that other animals can enter a mixed state of wakefulness and sleep, so dolphins are a very classic example of a dolphin, being mammals, they need to breathe to breathe, they need to go to the surface , be close to the surface. a danger to animals, so how can you do it?

How can you sleep and breathe without putting yourself in danger? So this solution for this in dolphins is to sleep one amis out of fear at the time, so when they sleep, you actually sleep with them during For example, the right hemisphere first, which allows the left hemisphere to call all the muscle activity into the neck. related to swimming and breathing and allowing them to surface breathing,

while

the other objective is very sleepy and then has the reader backwards and Emma. spheres like these are going around in order to sleep and this is something that is not only seen in dolphins but also migratory birds have this type of emergent field sleep so when they have to sleep for days or even weeks when we graze they will have a dream Emma sphere sleeping at the same time so there is already evidence in the animal kingdom or in certain pathologies that sleep and wakefulness can sometimes mix, what I will try to show here is that it is not a special case for special individuals or people specials.

In animal species, we also enter to some extent this state of sleep, mixtures of awakenings and the first thing I'm going to talk about is being awake while you sleep, so that when you are sleeping, your brain can wake up transiently and locally without no other sign of global awakening to explore this, I think the first thing that is important is to remember what sleep is because it is often a common word that we all use, but in the end, what does it mean to be asleep? And for this you have several potential definitions, the easiest one. one and the one that you can always use for example in your private life is to ask, so if you want to know if someone is asleep or not, you just have to ask if the person does not answer, it usually means that they are asleep, so from a perspective Behaviorally, sleep has always been defined by this state of responsiveness.

It is important to emphasize that this state of responsiveness because you are not sleeping does not necessarily mean unconsciousness because when we sleep we may be dreaming, for example, so we may be very well aware, it is just that we are usually aware of something completely different from the environment in which we live. that we sleep, so the main visual definition of sleep is that you can use it in humans if we trust each other, but how can you ask a fly if she is sleeping or any other type of situation where communication is a problem, so hopefully now we have another more objective definition of sleep accounting from physiology so that we can observe brain activity during sleep and can identify markers of sleep activity, for example in the transition from wake to sleep. dream, so wait, he is here and the dream is here.

We can observe these changes. Where is the brain activity that you are recording through an electroencephalogram? It shows an increase in the slower high-amplitude iation. By the way, this is a snapshot of one of the first. An EG paper published by Loomis in 1937, so perhaps one of the first published records, for example, and actually sleep, will be used to compare and make sure that EG was a good technique for recording brain activity because If you have a system that records electrical activity on the surface of the brain, how do I make sure it's meaningful information? So one way is to make a massive change in terms of behavior or what people experience and analyze how that translates in terms of brain activity so that that way they actually use Steve, to make sure that everyone was working and it was easy , still today, almost 100 years later, uses it as the best way to define whether someone is awake or asleep in science, so with more detailed techniques for recording brain activity we can also see how.

Sleep affects not only the overall electrical activity of the brain, but also the behavior of individual neurons. For example, you can see here what is a classic sleep activity with this high amplitude slow wave that we're going to talk a lot about today. What you can record on your scalp are often associated with episodes of neuronal silencing, so when you go from Y Funes to sleep, what happens in your brain is that your neurons more or less synchronize and will show this population activity where they will fire in unison and silence in unison and that changing from this synchronized activity to a very synchronous alternation of active and non-active state is really what characterizes sleep.

It is also believed to be the reason we lose consciousness when we fall asleep or enter dreamless sleep. or why we cannot respond to our environment because the brain, being hyper-synchronized, cannot do the calculation, it does it when it is awake, so this pattern of activity here is its activation and silencing episode that corresponds to it is slow, It is actually believed to be the basic element of sleep physiology, so this is a snapshot of a few seconds of sleep in a patient who has had depth electrodes implanted, so these patients are epileptic patients who They are implanted with electrodes to locate the site of the epileptic seizure, which is why there is a monitor in the hospital. for about a week to identify where the epileptic seizure is and then they will undergo surgery to remove this region of the brain.

The good thing is that sometimes these patients agree to have their data used for other purposes and for their own surgery and, in particular, for science. So this is work that I've done a lot with your varnish and the tone of every early group in Wisconsin to study the physiology of sleep from outside the brain, so here with a scalp EEG so you can record the kind of things . in any participant or healthy or LP patient and then, thanks to this patient, you can have information about what happens inside the brain, both about regional activity, for example, in a specific region of the brain, for example, the supplementary motor area , but you also have information about individual units, so how neurons work in unison and in relation is more of a global activity, so this snapshot of 20 seconds of sleep is representative of what was classically thought about sleep, so the dream is what I just described, it is very global.

Hypersynchronized state, you can see that very different regions, amygdala, hippocampus, inner cortex, supplementary motor areas, all these regions show more or less the same, so this wave that is synchronous and this wave corresponds to an episode of neuronal silencing that you can see in very, very different regions, so it would be a very surprising case of AI/synchrony because there are regions that are very distant and show exactly the same pattern of activity at the same time, the global picture of Sleepy that is actually not representative of what is happening. in the brain, a lot of times you have this even in regions that are in belogus, so right here, in the left parietal cortex and the right parietal cortex, you can see a wave in one region and nothing in the other region, sometimes also you can observe. a wave on the scalp so you can see there is a polarity reversal which is perfectly normal so you can see a wave on the scalp which corresponds to a wave in one region of the brain but not another so you can see here there is no neurons The subsequent silencing of this brain region in turn shows a slow wave, but nothing can be seen here in the left vital cortex or in the scalp, so it is a case where the slow waves that were thought that were hypersynchronous and global are actually local and if you detect the waves, this brain wave inside the brain and see how local or global they are.

You can see here that most of them are actuallylocal, so what that means is that this neuronal silencing that is classically observed in association with slowness is not happening. Everywhere, in some region of the brain, you can still maintain potential information processing, so that doesn't qualify us as close to dolphins, but it still goes in this direction that when you sleep on the left and right side of the brain, I can sleep in a different way. So this local modulation of the untreated amount of slow wave has actually been interpreted as a consequence of previous brain activity.

In this experiment, for example, they had participants perform a learning task in which they had two conditions, so this is a task that you have. - it is a motor task in which in one condition you are fooled or not, so in one condition the rotation is more intense than the other and potentially more exhausting and what they observed if after the most demanding tasks you can observe in sleep after that. This task is slower wave and higher amplitude slow wave in regions of the brain that correspond to the motor cortex, so the message of this very important article published in Nature in 2004 is that if you are overusing a specific region of the brain, you are building Increase the sleep pressure in that region of the brain and that pressure will result in more sleep in that specific brain region, so in some ways the brain will be able to adapt the depth of sleep depending on how much a request has been made. region during the day, but local sleep modulation is not about this absence or presence of slow waves, in some cases there may even be signs of local arousal, so it is not that sometimes there is or is not the presence of a sleep marker; in some cases it may even have the presence of clear markers of wakefulness while the rest of the brain's sleep remains asleep, so for example these are fixed data are recorded in patients to be implanted, so the conclusion here is what is recorded from outside the brain and what is remembered in the motor cortices or the prefrontal cortex and you can see that in these two cases they are two different patients. fluids that are very, very classic sleep, so someone who won't have access to information about what's going on inside the brain will say, well, these two patients are asleep, but if you remember different regions of the brain, you can see in these two cases that at some point one of the brain regions, so here the motor cortex just woke up for a few seconds, but that was not a global awakening.

I mean both at the scalp level and another brain region within the brain where no such local awakening was seen, so you see that things are a little flexible and it's not just that you can be more or less asleep in different regions of the brain, but you can even have one region of the brain waking up and another falling asleep. Another study this time carried out in Lyon showed that in France it showed that you can even have some type of behavior associated with this local arousal, so in this study they studied patients in whom they were interested in the sensation of pain during sleep , so they were inflicting some painful stimuli on people while they were sleeping and these people had to indicate by raising their finger when they were feeling the pain or not and they had this incident where you have someone asleep but locally in the motor cortex against your local awakening and this local awakening was paired with the person, the patient raised his finger in response to a stimulus, so from an external perspective, you have no reason to think that this person woke up at some point, but he did.

What you can see is that a region of the brain wakes up and this leads to some kind of interaction with the environment, so it raises this important question of whether sleep modulation is just about what you did the day before or the environment. where you sleep, can it also predict how different regions of your brain are going to sleep? So explore this question if a very interesting study published in 2016 while they were studying was classically known during sleep. literature like the first night effect, so the fact that when you sleep in a new environment you generally have lower quality sleep, so why would that be the case?

There may be obvious psychological advantages of this if you sleep in your environment. I don't know anything about it that could be dangerous, maybe it's better to have a lighter sleep than usual so you can respond to any threats, if any arise. What they saw in this study was that this dream lighting was not uniform throughout the brain. So actually, mainly the left hemisphere was sleeping less, like the leftist spirit was, you know, we're sacrificing the rest for the right hemisphere and sleeping less than usual in order to respond to the environment, so again. Going a bit in the direction of the dolphins, what they also showed is that this is not just some kind of sleep-specific illumination: the upper left part of the brain was actually more sensitive to the deviant sounds compared to the deviant sounds. standard during sleep. night, so this modulation of sleep death may have a functional advantage that allows you to process better or be more sensitive to unpredictable events in your environment, which is why you are guided by the research I did during my PhD, under the supervision of C Twitter.

This is a project that actually started collaboratively. We see Twitter and Tristan back in fashion in Cambridge. Well, the idea was to see if sleepers can flexibly process what's going on in their environments so that they can even respond or prepare to respond when they are. It stimulated so much exploration that what we did was a fairly simple experiment where we had people come in and we asked them to do a simple semantic categorization so that a series of words come to you through speakers and you just have to indicate in that case . If the word refers to an object, a spoonful of a knife or an animal sparrow, koala, this kind of thing, then they simply had to press the rights, for example, for an animal and leave it for an object, what we did was carry to chronically sleep-deprived students and make them happy. and we had them come to the lab sitting in a very comfortable chair like here, so the only thing is that the light was off and they were allowed to fall asleep, so what happens in that case is that they obviously do what we What we did was when we were able to confirm that there was deep enough sleep, so that represents a kind of ladder to deep sleep.

We continued presenting Z stimuli, but this time we presented new stimuli so that they never heard the same animal or object categories yet, but new ones. What we expected was that while they were falling asleep they would do this very monotonous task of responding from right to left depending on the category. semantics, we thought that maybe their brain would continue doing it while they fell asleep the advantage of having left and the correct answers is that it is something that you can actually see in the brain when you are preparing for a correct answer, it is your left hemisphere that prepares for that motor response and vice versa, so by comparing the left and right hemisphere we can track whether participants are preparing for the correct response and since the mapping of response and world category was completely arbitrary and counterbalanced across participants, If we see differences between the left and right Emma sphere during sleep, it is an arbitrary rule that cannot happen by chance, the only thing it can mean is that the participants are not only sensitive to sounds, but can also encode them, access their meaning and apply the rule to prepare the left or right response, so they mean that they somehow process the complexities of the environment and almost interact with them.

It's between each other that they obviously weren't pressing the button and in because that's how we define sleep by the absence of response, so what you see when comparing the right and left hemisphere when people are awake and responding is that type of activity, so which starts a little earlier. It's reaction time, you have this asymmetry between the right and left hemisphere that is centered on the entire motor cortex. What we saw in our sleep experiments was something quite similar in light sleep, so the same points in the motor areas and the same type of asymmetry. they just take a lot of delight in time, as if the calculation takes longer, but this delay in time is actually not that big, it actually corresponds to the reaction time they were doing when they were calm, so their brain was asleep. seems to be as slow as a drowsy. one, so obviously, even if we were expecting and looking for these kinds of results, it's pretty surprising to think that while you're sleeping you can still categorize words in your environment, so we tried to replicate those results in several experiments and we actually did it in three different ones recording in two different countries on three different tasks, so I think that's pretty good evidence that something is happening here, so the next question was whether sleeping people can process this information while they sleep, does it correspond to local sleep modulation?

Is it supported by this local aspect of the dream that we have seen before? So if I talk about it, it's obviously because that's how it is. This is this signature of a preparation of a response, so you can see that it appears in the motor areas around three. four seconds, so what happened in the brain when you present the sound is initially the brain's reaction is to increase synchronization, so this is the time-frequency decomposition of the brain reaction that you can see in the low frequency range and what is called spindle range. You have this massive surge in power, this massive synchronization that is at the center of the front part of the brain and that has generally been interpreted as a sleep protection phenomenon, so there is a disturbance in your environment.

The brain's reaction is to push you even deeper into what you notice after there is actually a decrease in this synchronization. This decrease corresponded in time to the lateralized preparation potential, so this motor response but also in space seemed like when you were when you received a sound while you were sleeping, the first reaction of the brain. is pushing you deeper, but on the second time, actually, the part of the brain that is relevant to the processing of this information seems to sleep superficially and this superficial sleep seems to be related to your ability to process this information.

I also looked at whether this local sleep modulation is sleep self-regulation and was associated, sorry for the typo, with learning new information during sleep, so I'm not going to present that because it's actually a pretty complicated article, but for break the suspense, yes. Let me you can learn during your dream, but this is also associated with this local dream. We also try to study the dynamics of this phenomenon, how sleep is dynamically regulated when there is information coming from outside and to do this we use a technique. It's called perfect reconstruction, where you can actually track what kind of information you possibly encode from your brain activity, so this stimulus reconstruction approach has several advantages, the main advantage is that you don't need to probe the brain at regular intervals. such as the event-related potential of seagulls.

In studies where you present one stimulus at a time, you can actually present normal speech to people and simply analyze their reaction to continue with the speech, so the way it works is that you can show that type of stimuli to the participants, to the stimuli, to the participants, so they are the most common. methods of crossing rivers, so just talk, this speech was presented to a ferret that was implanted in the auditory cortex. You can remember the ferret's brain activity and try to decode what hurt it and this is what makes you a little noisy, but still. understandable and it is even quite surprising since the ferret of course does not know English, so this kind of thing obviously works well when you can implant electrodes in animals and directly remember the activity of the auditory cortex.

It can also work in humans if the activity is remembered. from the outside only that instead of reconstructing something complex that you can even hear and touch, what we reconstruct is the envelope of fluctuation sounds in the acoustic energy of a signal because when I speak, for example, there is modulation in the intensity of the sound that I pronounce and imagine that you are in a discussion two people are talking at the same time if you concentrate on one person versus another your brain will be more sensitive to the fluctuation in the acoustic energy of the person you are listening to with another, so if you can track this fluctuation of the envelope, you can predict whoyou're listening using brain activity, so this is pretty much what's presented here, you retrieve the EEG from the EEG of your constricted envelope and then you compare. the envelope with the impulses or original signal and you try to guess in the case of several people speaking at the same time who you are attending to so what we decided to do was with you that type of thing we have to see if people can select information from there because So far we have shown that they can access information in their environments, so we wanted to see if they can select what is most relevant, so we put sleepers in situations where they are presented with two types of information, one that is relevant and another than the one that is not relevant so that it is easier for those who sleep to know what is relevant or not, what we use is speech because we are quite used to speech and we present two types of speech, either a speech in French, because this experiment was carried out. in Paris or something that looks like French that has the same grammar and the same phonology as French, but it just has no meaning, so I just made up words, so the technical term in linguistics is Jabberwocky in reference to Lewis Carroll, like this that basically there were more sleepers listening. to the French or the French Jabberwocky and what we wanted to see if they will be attracted to the significant transmission.

The good thing about the Jagga is that if you don't know any French you can't tell the difference between the two, they are actually the same, but if you know a little French this will automatically attract you, so just to give you an example, this It's English, no, oh brain, a lot of information, there's a bit like I just played here, yeah, since the brain is not. an inactive brain but it can actually deal with a lot of information, so it will be a Jabberwocky of this sentence, so now you can speak English, so the people in the room find it quite easy to concentrate on English while the significant current and even all the other and this is something we do quite automatically, so our question was: does the sleeping brain also make this type of selection of information based on this meaning?

That's the general protocol, so I'll talk very quickly about it, but there was a training part where we built a model used to reconstruct stimuli and then parts were even exposed to Jabberwocky or real speech both in wake and sleep and what we did was record to reconstruct what they were hearing, so to speak, and compare it with the meaningful stimulus or the meaningless one and which is better, we ourselves construct what we ourselves can best reconstruct the meaningful stream, but not in the dream and this It's not trivial because if we present both apparently, it actually reconstitutes them equally well if you tell people to focus on the Jabberwocky, this time you time the chatter weakly well, so it really is related to the focus of our attention and not with the nature of the stimulus and what we show here.

Even when we're asleep, you have the limited advantage of meaningful sleep by limiting yourself to Simmons and this was done throughout sleep, so both light and fast, these effects are actually even stronger in light sleep, the Which is why I'm talking. This is because with this type of technique we were able to act and see how information processing was temporally and dynamically regulated during sleep because, as I told you, during sleep we have these slow waves that occur from time to time, the wave slow that I have associated with neuronal silencing. What we observe is during the slower wave, so when we block the stimulus or the constriction in the slow form, we lose the ability to count on the two stimuli during a slow wave, but what is quite interesting is what happens after of the slow wave, after a slow wave, you not only reconstruct more than chance above zero the two stimuli, but you begin to see a difference between the meaningful and the meaningless and whether each slow wave will kill any information processing that you're doing but it will also give you a short window right after the slow one. say hello when you're a little more awake and a little more able to not only process what's going on in your environment but also select what information is the most important and I think this is actually a pretty neat and beautiful mechanism, you can imagine yourself sleeping. in a room, if there is an isolated salt that is not very interesting, you should not wake up to any isolated sounds that occur during sleep, so the good thing about this low wave is that if they are triggered, and they are often triggered by stimuli If you eliminate the activity associated with this, you will not process isolated sounds, but if you have a series of sounds, if the first sound is followed by other sounds such as the opening of a door followed by footsteps, then you have a window to which You are actually quite sensitive. what's happening in your environment, so it will boost your ability to process information that is quite relevant to you and this is you because the fact that sleep is a flexible and self-regulated process, so I'm going to move very quickly on this, for What sleep is not a monolithic phenomenon and the way each version sleeps depends on previous activity and environment, oldham, and now I'm going to talk about the kind of thing I'm doing here, which is the reverse image of being awake. while sleeping, which is being asleep. while we are awake, then if we recognize that dream activity depends on previous activity and that some region of the brain may be more linked than the other, it means that they may also follow the dream before the other, so this is something which has actually been shown in animals if sleep deprived, for example, you can see in wakefulness the slow way in which neuronal silencing occurs, whether local or global, which is quite reminiscent of what happened during sleep and is becoming more frequent the more sleep deprived you are, these rats are very important.

They can be associated with behavior, so when they occur in a task, they are usually followed by an error and this is done in a region-specific manner, so if a reed brain region is important for performing a task , here is the prefrontal cortex, any slow waves that occur. in that region will tend to impact the behavior without the regions that are not involved in the task not impacting the behavior, so it seemed that when you target a part of the brain it can go to sleep and if a specific region goes to sleep then it will disturb what This is supposed to do a specific brain region of the brain and that can have a consequence on the way we behave, so this is something that we confirmed even working with Yuval around this implanted patient, so they had to perform simple visual tasks where they had to do. simple facial recognition and we looked at their reaction time and what we saw that goes wrong, so when they get tired they tend to get slower and slower, these lapses were actually associated with a reduction in the firing of neurons, so the neurons themselves are somehow getting tired locally, this type of sleep-related activity in wakefulness can also be observed using scalp EEG, so on scalp EEG you can occasionally see this Slow delta theta wave that increases in number with fatigue and also questions associated with behavior. deterioration, so there is a good index of this fatigue and this tendency of brain fatigue to go into a mixed state of sleep and wakefulness, so this is actually a project that we are doing here at MBI with this student Eva was the McCain game honors project for Let's see how this local dream affects not only objective performance but also subjective experience, so we have a task that has been designed to be very, very boring.

People do this simple go/no go task and we examine their performance on the task, but we also interrupt them from time to time to tell them what was on their mind, whether they were concentrating on the task, whether they were thinking about something else. thing or if they were just focused and what we observed is that, first of all, there is They focused on the task only 50% of the time, which is worrying, but it has been shown in many, many Bader. What we also observed is that in the EEG we were able to detect these local sleep events, so this local snow wave, if just for comparison, this is the type of wave detected while awake is the same as detecting it during sleep, so which is very, very similar, the only difference is the amplitude.

What we also observed in these participants, if the number of these slow waves was positively correlated with fatigue, then this is quite interesting because these people were not sleep deprived, I mean, they are as restless as you, but from time to time They showed this slow intrusion of waves during wakefulness and this correlated with fatigue, so Lobell sleeping awake does not seem like an extreme event. It could be something very common that happens every time we are tired. We will also see that the prevalence of this dream was negatively correlated with behavioral efficiency, so they were slower when participants were impulsive or quite slow on the task and this has an opposite relationship with PBO sighs, so it seemed that when people get tired, when people get smaller, this also corresponds in the brain to the appearance of this local snow wave.

This local snow predicted errors, but in a very interesting way because I also found that this regional specificity, what happens is not so much the occurrence of the slower ones, but where they heal, for example, when slow waves occur in the frontal part of the brain, is positively correlated with false law in impulsive behavior and when it occurs more in the back of the brain. The brain correlates with increased errors or slowed reaction time, so when you get tired, your brain region is more likely to enter the local sleep state, than when the region enters this sleep state. local will affect behavior, so in this scheme This way, if it is the front part of the brain, you become more impulsive because you lose executive control, if it is the bias of the brain, you become slower because you process your environments less and Finally, that would be the last result of this.

We also saw that this local slow waves also predicted the type of subjective experience people had, so they were more present when people wandered and even more so when they blinked and their amplitude also predicted the type of distraction people experienced even while respecting . this frontal parietal division, so when, as always, they are larger in the front part of the brain, people have a tendency to think more like they can still be conscious but they can't control the flow of their thoughts when it's up here , at the rear. of the brain were more likely to have a blank mind, so they were not thinking about anything, so we can complete this picture by saying that not only local sleep impacts behavior but also debugging behavior in the region in a specific way which will affect both objective behavior and subjective experience.

So, to briefly conclude on that part, it seems that sleep deprivation can occur when we are sleep deprived, but no, not only when we are sleep deprived, so it seems like a pretty general phenomenon and this phenomenon has consequences in the way in which we interact with your lab, so I'll end with this nice quote from William Shakespeare about the importance of sleep in our daily lives and how the time of awakening and the time of awakening and the night can deeply impact each other and how during the day we can enter this combination of waking states. and sleep and how this will affect the way we actually interact with your environment, so I'll end by thanking the audience and all the people involved in this project.

You can see that network of quite a few people, mainly in Monash, in different subjects in the Faculty of Psychology because it is really an integrative research that touches on many different topics, but now you will also think mainly about sushi and also gia lab because that is where I spend the most part of my time and I am very happy to I joined this team because I think we are going to do great things, yes, thank you, it was a very fascinating talk. I have two questions, one is more of general interest and the other is more of an applied question.

So with that applied, I was wondering that there are many roles in society that require people to stay awake for very long periods, like doctors, for example, or people in the military. Do you think there is a way to optimize the local sleep phenomenon that would allow you to say? doctors to tasks that optimally allow some aspects of their brain to sleep and others to remain active and do so in some way that reduces errors, reduces risks, etc. That's actually a very good question. There is a lot of research that has been done on how we can optimize whereWe can sleep, how we can optimize wakefulness when we have to do something important and how we can detect cases where it is better to go and rest, also approaches within sleep to understand how we can wake people up in the most efficient way.

What are the stages of sleep when it is best to wake people up? But also more interventionist approaches to sleep. That's why there is a whole series of research on slow wave momentum, which is why the slow wave seems to be closely linked. to the recovery aspects of sleep and are sensitive to sounds, so one idea is to play the sound in sync with the slow wave to try to entrain them, make them bigger, and ultimately make the sleep more restorative. and it works to some extent, so you can do this. It's always bigger and seems to reduce the time you need to sleep a little.

The best time is a big unknown for these approaches, we don't know the long-term consequences and we know that sleep is sensitive not only for brain function but also for your entire physiological function is quite risky, so it can keep people for long periods of time, but that can have dire consequences down the line. Maybe you can try optimizing waking sleep to not keep them awake, but just to see if they can sleep. less but but we have no idea what the consequences may be, thank you and if you don't mind, unless there are urgent questions.

I have a very quick question about the function of surprising sounds that are not followed by important ones. sounds while you sleep, the subjective experience is often that sounds in the environment can very quickly become incorporated into your dreams. Do you think that's some kind of expression of that function? Actually, when you look at the research done on this, it's actually the other way around, most sounds don't get incorporated into dreams, it's very difficult to efficiently incorporate sounds into dreams, usually when they cooperate, lead to an awakening. That said, so surprisingly few have been done in dream research that perhaps just people didn't do it. use a quick simulation, all right, the right way to do this, so there's actually a lot of novel interest in this, for example, now you were telling me that you visited the lab in Chicago where they're using lucid dreamers so that people who They can communicate while they sleep and have examples of people who can actually report hearing things during their sleep, so not only do they incorporate what is coming from the outside, but they can also differentiate it from what they are dreaming about, so it could be more rich.

It may be that in reality many stimuli are being incorporated but you converted them into something else and then you did not realize that they were being incorporated because just like an alarm call and it becomes a bell, perhaps many times there are things that are transformed and clarified. during we sleep, so we don't realize that we're actually incorporating it, but the state of the literature is that we incorporate very, very little of what's in our environment while we're dreaming, so we have a Zoom question, a fantastic chat with Dr. Andrew Ellen, have you looked at the impact of a local injury, i.e. stroke, on local sleep?

Are there compensatory sleep mechanisms that allow the contraoriental hemisphere to sleep more? I've never heard of anything you're talking about, but that's really it. A very interesting question. I think the state of the local sleep literature is more that it's at the point of proof of concept in some ways, so the fact that it exists is what matters, but most of the time it's been done in healthy populations who sleep well, so there are now many opportunities to look at more special cases, so a stroke patient may be something interesting. I know that it is necessary to have a project on apnea and local sleep so that sleep apnea wakes up parts of the brain more than the other and how the consequence of this here at Monash and that is actually part of my NHMRC ECF we wanted to look at it in terms of local sleep abilities and whether some people sleep more locally while sleeping than others, particularly people with insomnia or who report not sleeping well, perhaps one reason they don't sleep as well if they are sensitive to the environment environment, it's actually because their sleep is more fragmented than people who sleep well, so studying these interindividual differences is actually I think the next step in this topic.

I have a question about how many different parts of the brain there may be that can sleep independently. Hmm, I think you gave mixed results in your talk. One was with finger pain stimulation, where people seem to have a motor cortex that was awake while they were sleeping, but then in language lateralization. homework, thanks, surely there was no differentiation, so are there a number of brain regions that could be dormant separately in your view? So I think it's a global gradient actually of increasingly more or less massive differences. It's interesting to see how the octopus is asleep and has many different brains somehow.

So what is brain sleep like? I'll be quite interesting in terms of the mammalian brain. There are still a lot of things that are unclear and most of the time we study the cortex and the cortical regions, so they are pretty well interconnected, so it is potentially unlikely that things will be broken down into five different regions and tilted. in five different ways, but then you have some subcortical nuclei and many of them show activity during sleep. completely different from the rest of the brain, but these maps have not been enough, there could also be some finer subtle differences, which is why recently the Tononi group published a very surprising article where they show that during REM sleep the different layers of the brain are mapped.

Cortex. By not sleeping in the same way, in some layers you can see slow waves and in others not, and we have no idea why this is the case, so it is very likely that this dynamic is much more complicated than the original image of the context . Globally there can be many differences that are due to previous activity in the environment or even the anatomy of the brain. I'm just curious, I'm guessing it's partly related to pathology, for example, increasing sleep in discretionary sets where we use moment by moment that we go to, even if it's not, for example, in the middle of a conference, in the case of, for example, people with narcolepsy who similarly fall asleep without any real warning, we know a lot about why what's going wrong there, so I'm I don't know much about narcolepsy, I actually know that it's quite well studied and it is one of the problems that have been solved in some way, so I will not dare to say much about the mechanisms, but yes, the mechanisms until the end.

The genetic level of narcolepsy, as I've been studied, that's why they make this sudden transition, it's well understood, but that's actually something that I didn't include here, but in sleep onset we can see these regional differences, so that not all. region of the brain falls asleep at the same time, which can sometimes explain why we can read a book first and wake up in the morning and not forget anything from the last pages, so it could be because the thalamus falls asleep earlier . the cortex so we can be when we fall asleep in a state where we maintain consciousness we maintain some type of awareness of the environment but all this information does not pass to the hyperfield that has already begun to fall asleep or because there is no transfer of information, so this part is lost and narcolepsy, therefore, may be one of these other examples that sleep onset can vary by individual in its dynamics or how sudden it is, etc., are there any other questions we have for Thomas ?

So, well, I guess this reminds us that we should thank you again and, if possible, I will scare a little and remind people that this is a regular event for this seminar and that next month we will hear from some of the people here at MBI involved in preclinical imaging that may be of interest to you and also asked me to remind everyone that the Convergence Science Network will have a session here at MBI on May 7th and will participate from time to time. colleagues and examine the question: who do you think you are? Philosophy, neuroscience and the nature of consciousness so that the image resonates with this audience as it is right now.

Thank you all for your attention and remember that we have this meeting quite regularly. you a lot