Understanding and Using Dreams to Learn and to Forget | Huberman Lab Podcast #5 Flashcards
How would you describe the cycle of sleep?
So early in the night, a lot more slow wave sleep
and less REM. For every 90 minute cycle that we have during a night of sleep we tend to start having more and more REM sleep. So more of that 90 minute cycle is comprised of REM sleep and less of slow wave sleep. Now this is true regardless of whether or not you wake up in the middle of the night to use the restroom or your sleep is broken.
The more sleep you’re getting across the night, the more REM sleep you’re going to have. And REM sleep and non REM, as I’ll refer to it, have distinctly different roles in learning and unlearning, and they are responsible for learning and unlearning
of distinctly different types of information. And this has enormous implications for learning of motor skills, for unlearning of traumatic events, or for processing emotionally challenging
Which neuromodulators are active during sleep?
Acetylcholine production plummets. It’s just almost to zero. And acetylcholine as I just mentioned,
is associated with focus. So you can think of slow wave sleep as these big sweeping waves of activity through the brain and a kind of distortion of space and time, so that we’re not really focusing on any one thing.
Now the other molecules that are very active at that time are norepinephrine. Which is a little bit surprising ‘cause normally in waking states norepinephrine is gonna be associated with a lot of alertness and the desire to move. But there’s not a ton of norepinephrine around in slow wave sleep, but it is around. So there’s something associated with the movement circuitry Going on in slow wave sleep. And remember, this is happening mostly at the beginning of the night, your sleep is dominated by slow wave sleep.
So no acetylcholine, very little norepinephrine, although there is some and a lot of serotonin.
And serotonin again is associated with this desire, this sensation of kind of bliss or wellbeing,
Why is slow wave sleep important?
So we can think of slow wave sleep as important for motor learning, motor skill learning
and for the learning of specific details about specific events.
what is REM sleep?
There are a couple of things are happening besides rapid eye movements. The main ones are that they’re, I should say, in contrast to slow wave sleep. In REM sleep serotonin is essentially absent. Okay?
So this molecule, this neuromodulator that tends to create the feeling of bliss and wellbeing and just calm placidity is absent. All right. So that’s interesting. In addition to that, norepinephrine this molecule that’s involved in movement and alertness is absolutely absent. It’s probably one of the few times in our life that epinephrin is essentially
at zero activity within our system. And that has a number of very important implications
for the sorts of dreaming that occur during REM sleep and the sorts of learning that can occur
in REM sleep and unlearning
How about emotions than in REM sleep?
So we have this incredible period of sleep in which our experience of emotionally laid in events is dissociated. It’s chemically blocked from us having the actual emotion. It’s important because it allows us to experience things, both replay of things that did occur as well as elaborate contortions of things that didn’t occur. And it allows us to experience those
in the absence of fear and anxiety, and that it turns out is very important for adjusting our emotional relationship to challenging things that happened to us while we were awake. Those challenging things can sometimes be in the form of
social anxiety, or just having been working very hard or concern about an upcoming event, or sometimes people report for instance, dreams where they find themselves late to an exam, or naked in public, or in some sort of situation that would be very troubling to them.
Recap what are the two fases of sleep?
Slow wave sleep early in the night. It’s been shown to be important for motor learning and for detailed learning. REM sleep has a certain dream component when which there’s no epinephrin, therefore we can’t experience anxiety, we are paralyzed. Those dreams tend to be really vivid and have a lot of detail to them. And yet in REM sleep what’s very clear is that the sorts of learning that happened in REM sleep are not motor events. It’s more about unlearning of emotional events.
And now we know why, because the chemicals available for really feeling those emotions are not present.
Now that has very important implications.
So we should really think about REM sleep and slow wave sleep as both critical. Slow wave sleep for motor learning and detailed learning. REM sleep for attaching of emotions
to particular experiences. And then for making sure that the emotions
are not attached to the wrong experiences and for unlearning emotional responses
if they’re too intense or severe
REM sleep and meaning
so REM sleep is very important for remembering location as the same nerouns are used during the sleep than physically going to the place.
Also, REM is important for creating meaning. These general themes of things and locations and how they fit together and that has a word it’s called meaning. During our day we’re experiencing all sorts of things. Meaning is how we each individually piece together
the relevance of one thing to the next, right? So if I suddenly told you that, you know,
this pen was downloading all the information to my brain that was important to deliver this information, you’d probably think I was a pretty strange character. Because typically we don’t think of pens as downloading information into brains. But if I told you that I was getting information from my computer that was allowing me to say things to you, you’d say, “Well, that’s perfectly reasonable.” And that’s because we have a clear and agreed upon association with computers and information and memory, and we don’t have that same association with pens.
You might say, “Well, duh.” But something in our brain needs to solidify those relationships
and make sure that the certain relationships don’t exist. And it appears that REM sleep is important for that, because when you deprive yourself or people of REM they start seeing odd associations,
Furthermore, REM sleep is powerful and has this amazing capacity to eliminate the meanings that don’t matter.
It’s not that it exacerbates the meanings that do matter, but it eliminates the meanings that don’t matte
Is there a comparison between REM and for example drugs or therapy?
Ketamine is about becoming dissociative or removed from the emotional component of experience. So now we have ketamine, which chemically blocks plasticity
and prevents the connection between an emotion and an experience. That’s a pharmacologic intervention. We have EMDR, which is this eye movement thing that is designed to suppress the amygdala, and it’s designed to remove emotionality while somebody recounts an experience. And we have REM sleep, where the chemical epinephrin that
allows for signaling of intense emotion and the experience of a tense emotion in the brain and body is not allowed. So we’re starting to see a organizational logic, which is that a certain component of our sleeping life
is acting like therapy.
Consistency or always aim for the longest amount of sleep??
But, I found it striking that the data from this study really point to the fact that consistently getting about the same amount of sleep is better than just getting more sleep. And I think nowadays so many people are just aiming for more sleep, and they’re rather troubled about the fact that they’re only getting five hours, or they’re only getting six hours in some cases. It may be the case that they are sleep deprived and they need more sleep, but some people just have a lower sleep need. And I find great relief, personally, in the fact that consistently getting, for me, about six hours or six and a half hours is going to be more beneficial than constantly striving for eight or nine and finding that some nights I’m getting five and sometimes I’m getting nine and varying around the mean. As I recall, and I think I’m gonna get this precisely right, but if not I know that I’m at least close. For every hour variation in sleep regardless of whether or not it was more sleep than one typically got, there was a 17% reduction in performance on this particular exam type.
