Using Sleep to Understand how we learn | Dr Rebecca Spencer

Benjamin Hopkins (0:04)

Your research is so fascinating, and you spend a lot of time in a world, like not a lot of us have, which is how sleep affects what we remember, specifically with regards to emotions, and most of us just sleep with how we feel the next morning, but you look at sleep in a slightly different way. How did you end up studying what you, or researching what you researched?

Rebecca Spencer (0:26)

It's a good question, because I really feel like I just followed the path where different things led me to.

I actually did not start out trained in sleep science. I kind of stumbled into it. I was very interested in these questions of how we learn to make different movements, which is really important to people that maybe had a stroke and are trying to relearn to move. And in doing so, some work had come out to say that sleep was important to this type of learning. And I got interested in just what role would sleep play. And then one question led to another led to another, partly because every time we would answer a question, the answer was surprising and not really what we would expect. And it just led me into this space that we knew so little. Even though we think about sleep a lot, everybody does it. Hopefully does a lot of it. It's still surprising how little we know of it. And so I just kept following where those answers would lead me.

Benjamin Hopkins (1:24)

Wonderful. How has sleep changed your view on how humans learn?

Rebecca Spencer (1:31)

Yeah, I think we take this for granted a lot, is that sleep plays a big role in preserving memories. And yet people pull an all-nighter to study for an exam. So there's clearly a disconnect in the pop culture about the relationship between sleep and learning. I mean, of course, you've got to get information into the brain or sleep to have anything to do with it. But once we've put that information into the brain, it just goes into this short-term storage place called the hippocampus. And that's a good rapid learner. The hippocampus could take in stuff pretty fast. But it's not good in terms of long-term memory storage. It doesn't have organization to it. It can get overloaded. And so you really need to get the information from that short-term storage place into the longer-term, the cortex, the more organized cortex. And sleep is really critical for moving it from one place to the other.

So I've equated it to collecting papers on my desk. So throughout the day, people will come by, drop papers on my desk, I'll have notes from a lecture, I'll have papers that need to be graded. And they're all one big unorganized pile on my desk, which is fast, like the hippocampus, but not organized. And so what sleep does is it takes those things that have just piled up throughout the day and now puts it into the cortex, and the cortex is much more like a filing cabinet. And the filing cabinet means I can have specific places to put different types of information, which has a lot of advantages, because now when I go to find something, it's tabulated, I can find it more easily. But it's also stored with other information that might be like it. So rather than just finding this most recent information about what dogs look like, I could store that away with a lot of different incidences I've had with dogs and create this overall picture of what I think about dogs. And so there's a lot of advantages to that system of moving things from that fast learning hippocampus to the very much more organized cortex. Then the other thing that does is it leaves the hippocampus kind of as a clean slate. So it also gives us this advantage that now when I'm trying to learn new stuff, I could take on new stuff. It's not going to interfere with all those papers that were already there. So it's just really simple but at the same time complex system because it's providing you so much advantage to your memories that I think we completely take for granted. And so I think sleep has a lot of power. The other thing I'll say on that too is that I think we have a tendency to think of sleep as so singular and that you just go to sleep, you turn the brain and the body off and that's it.

But not only do we know like, well, the brain is super active while we're sleeping, but it's also going through these different stages. And so rather than just thinking of sleep as being this one mush of an activity, it's doing different activities throughout different cycles of sleep and different brain areas are active at different times.