Matt Jones - Sleeping and learning

Kat - You've probably heard the phrase "sleep on it", to help you solve a problem. And it's often said by students that a good night's sleep after revising is better than an all-nighter of cramming. But why? One person who's trying to figure out how sleep helps us learn, and how sleep problems might be involved in brain diseases such as schizophrenia, is Matt Jones from Bristol University, who also helped to organise the Genetics Society Autumn meeting.

Matt - The man on the street will acknowledge that sleep is important. We all feel a bit rough if our sleep is disrupted which obviously has, a long time ago, raised the question exactly, what is sleep for. It's clear, based on what's going on in the brain during sleep, that it's not just a time of rest. We're not just recuperating. We're also sorting through, in our sleeping minds, the wheat from the chaff and deciding which information to hold on to, to consolidate and which information perhaps is not so important and we can choose not to remember in the long term.

Kat - And there was kind of a bit of a thing at university. You'd say, if you're studying for an exam, do some revision then 'sleep on it' and you'll know it better the next day.

Matt - That's right. there's well-controlled evidence that good night sleep will improve your performance subsequently. So, we should all strive to sleep more and better I think.

Kat - How do you try and study the impact of sleep on learning? What are you doing?

Matt - We're using a translational approach. So, we're studying sleep in rodent models - in rats and mice in which we can study brain activity during sleep in great detail, trying to understand how information is processed in the brain during sleep in these animals. And then at a more clinical extreme, we're studying patient groups who have disrupted sleep and trying to understand how their disrupted sleep impacts on their symptoms and in particular, in memory impairment. So to date, we focused on Schizophrenia which is a disease that if you ask a psychiatrist, they'll be quite dismissive about the role of sleep disruption in that disease. But if you ask a patient, they often cite bad sleep is having a major impact on their quality of life. So, we've seen in one cohort, patients suffering Schizophrenia that their brain activity during sleep is abnormal. So, it's not as well coordinated as it is in healthy volunteers and that the extensive disruption in brain activity during sleep correlates with the extent of memory impairment. So, this obviously offers an opportunity to intervene, to try and normalise brain activity during sleep in Schizophrenia and hopefully, show that has a beneficial effect for patients.

Kat - So, how are you trying to unpick maybe what's going on at a deeper level in the kind of the nerve cells and the molecules that are involved as we learn when we sleep?

Matt - In those experiments in animals where we can record from individual identified nerve cells and track their activity both during learning so, during waking behaviour and during sleep. There's the possibility for us to capture those cells, control their activity. So for example, you could bias the kind of information that animals store in long term memory by activating particular groups of nerve cells during sleep. And so, it's a sort of an interesting experiment. Our goal is not to control the minds of rats but it offers us insights as to what is going on in the human mind during sleep.

Kat - So, by stimulating different bits of a rat's brain while it sleeps, you can kind of make it remember something more or make it forget something that it really needs to remember.

Matt - Yeah, exactly. And so, you can immediately think all sorts of nefarious military motivated experiments that the CIA might be interested in. but I can assure you, we're not funded by them!

Kat - What do you still need to find out about what's going on when we sleep? What are your your known unknowns?

Matt - One of the big issues in the field remains what's going on during different stages of sleep. So, as most people know, we have different stages of sleep that we cycle through during the course of the nights Most famously, we have REM - Rapid Eye Movement sleep - and non-REM sleep. It's still not clear what those two different stages are contributing, particularly in the context of learning and memory. So, if someone chose to give me a few million quid and said, "Go and do what you want", I would try and focus on what's REM doing, what's non-REM doing and how do the two stages of sleep work together to finesse learning and memory.

Kat - And you've presented your results here at the Genetics Society Autumn meeting. What do we know about how genetics or genetic variations affect this sort of sleep and memory issue?

Matt - Well, I certainly don't know enough, obviously. In relation to the Schizophrenia work we're recruiting healthy volunteers at the moment on the basis of their genotype, that's at loci that are related to risk psychiatric disease. So, we're trying to use that approach to understand whether sleep disruption earlier on in the disease can exacerbate symptoms. But one appeal of sleep is that it's quite easy to measure at a population levels. So, lots of people wear wristbands that might monitor their movement for example. If hundreds of thousands of people are doing that, if we can capture those data and relate them to genotype, perhaps we can begin to tie these things together.

Kat - Matt Jones from Bristol University.