REM sleep history + why dreams were hard to study causally

3:10practice these in the ancient temples with the Egyptian deity Imoteep. Do you remember the mummy? >> Yeah. Yeah. Yeah. [laughter] Exactly. And then I mean it's been it's been a thing of research for psychoanalysis for quite a while. Sigman Freud was really into it. Carl Jung was really into it. But the modern birth really came in 1953 when Aserinsky and Clayiteman discovered something called rapid eye movement sleep. Okay? And they linked that sleep stage to vivid dreams. What was really the breakthrough here is we didn't have a subjective telling of, "Oh, I dreamed and that was the stage that I dreamt." Because what

3:51they could do is they could hook up electrodes onto the skull and they could actually see signatures of dreaming that were not based on subjective reporting. Right? You don't have to wake up and be like, "Hey, I was dreaming." You could look at the eye movement during sleep. There's a certain part of sleep called REM sleep, rapid eye movement sleep where your eyes move very rapidly. During that part, the electrphysiological signature from the EEG electrodes is actually very distinct compared to other parts of sleep. So it was this real actual stage in the sleep cycle. It happens about 25% of total sleep. Happens about 90 minutes after

4:33you fall asleep. And then during REM, what we've realized over the years of you know doing research on it, the brain is highly active. It actually resembles the waking state. If you look at the ephys signature, like the electrode signature of what these little electrodes on our skull picks up, >> and then you look at other stages of sleep versus when we're awake and we're like looking at stuff and and thinking about stuff, the electrphysiological signature during REM sleep is more similar to wakefulness >> than it is to other stages of sleep. >> Mhm. >> Right. So when we're dreaming, it's almost like the brain is kind of awake. Mhm. >> But obviously we're still asleep and

5:14it's been this really cool enigma to try to figure out. So the starting point was we you had the subjective experience from [snorts] people saying while I was sleeping I saw stuff. >> Yeah. But we did not at the time have a way to quantitatively track with instruments that state that people were describing that they were having until in this historical context we used electrodes and tracking the brain activity to see and mapping it with this rapid eye movement sleep that >> there is a state while you are asleep >> where the brain activity looks very akin

5:54to awake state and that maps to when people are now have you can now map the the data with the subjective reporting from those sleeping and kind of map those two together. >> Exactly. And then let's go even further. Right. So now we figured out that there is definitely such a thing as REM sleep. Yes. And that's probably when you're dreaming. >> Yes. >> Now what if we wanted to talk about dream recall and how that affects how you solve problems the next day or dayto day, right? That's still correlational still, right? Because the subject has to recall the dream. Mhm. >> And then there's there's some correlation between him recalling certain dreams and the creativity that

6:35he has the next day. There's some correlation between sleep deprivation and insight. Like there's a decorrelation really. It's like because like the more you're sleep deprived, the less you're really going to do novel stuff the next day. You need you need your sleep in order to actually fully function. But these are all correlational, right? You can't do a causal mapping >> meaning like this caused that. >> Exactly. Yeah. It's always just observational studies and this breakthrough which was in the neuroscience of consciousness. This is a causation study >> between your dreams and your ability to solve problems. >> So before we were just saying these two

7:16things are happening at the same time and so we think they're related. >> Yeah. >> But we didn't really see the bridge between the two things. >> Yeah. Yeah. Yeah. we weren't able to literally like influence the dreams and now this is what's happening. That's