Science Interviews


Sun, 3rd Apr 2016

Sleep, memory and schizophrenia

Dr Ullrich Bartsch, The University of Bristol

Listen Now    Download as mp3 from the show Can You Boost Your Memory?

Weíve heard how sleep plays a pivotal role in making our memories strong and resilient sleeping commuterbut, well it is a little complicated! And if somethingís that complicated then there are many ways for it to go wrong. Many people donít realise but one of the most debilitating symptoms of schizophrenia is actually the mental impairments particularly memory loss, so has this got something to do with sleep? Connie Orbach met Dr Ullrich Bartsch at Bristol Univeristy's sleep lab to find out...

Ullrich - Weíve got an MRI scanner over there and the facility for experimental rooms and meeting rooms.

Connie - A sleep lab is exactly what you might imagine.  Itís a bit like a hospital - thereís a bed, a bathroom and well... then there's all types of kit to monitor you muscle tone, your brainwaves, eye movement and infrared cameras to watch you while you sleep.  So maybe a bit more creepy than a hospital.  And next door to this room is where Ullrich Bartsch and his colleagues will sit for hours on end, night after night, measuring their patients quality of sleep by the different patterns of brainwaves detected.

When we sleep, we cycle through different stages.  First very deep, slow wave sleepÖ Next we move into lighter sleep, characterised by bursts of spikes called sleep spindles and finallyÖ REM sleep - smaller faster waves.  Okay, but I know what youíre thinkingÖ What on earthís all this got to do with memory and schizophrenia?

Ullrich - Sleep has been shown in the past 10 or 20 years to be important for memory consolidation and one of the biggest problems in mental health, particularly in schizophrenia, is the treatment of cognitive deficits.  And one intriguing fact that has long been anecdotally reported is that schizophrenia patients will initially start losing their regular sleep pattern before their psychosis kicks in.  That is mainly the loss of one particular oscillation that occurs during sleep and these are these spindle oscillations that Iíve mentioned earlier.

Connie - Schizophrenics show less of one particular type of sleep wave - the spindle.  And as Matt said, patterns of brain wave are important for memory but how do we show thatís really whatís behind their forgetfulness.  Well, that brings us back to the sleep labÖ  Ullrich takes healthy people and pre-symptom schizophrenics and gives them a simple movement task. Thinking I had an opportunity for a fun test, I decided to give it a go myself.  I had to type out a five digit sequence as fast as possible over and over againÖ 14132, 14132, 14132, 14132, 14132Ö You get it.  I did this twelve times with a break between each trial.  Over the twelve tests people improved but the real kicker is that after a nights rest when they do the task again, they have improved a lot more.

Ulrich - In the motor task, I think you can reach up to 30-40% improvement.

Connie - But what about schizophrenics?  Well interesting, when they sleep, they donít improve at all.

Ulrich - So the spindles, that Iíve mentioned earlier are, in fact, correlated with the amount of improvement that you show the next morning after youíve slept over learning a motor task.

Connie - So the more spindles you have the better your improvement - is that right?

Ullrich - Yes, thatís correct.

Connie - If I remember correctly, you were saying that in schizophrenia that schizophrenics have less of these spindles during sleep and so what does that mean when you get schizophrenics to do this task?

Ullrich - So they, first of all, perform much worse on the motor sequencing task.  So their initial learning is already lower, so they would have difficulties with motor coordination but also, if they would sleep for a night and wake up the next morning and be tested again, they would not have improved in that particular task.

Connie - Not have improved at all?

Ullrich - They wouldnít have improved at all.  Of course, there are some participants who do better than others but on average, if you take a relatively large group of schizophrenic patients, they would show little or no improvement. The idea is that because they have less spindles, they cannot process the information that theyíve taken up during a day as well as during sleep and they can, therefore, not strengthen these memories during sleep and then cannot show improvement in the task the next morning.

Connie - Now we know that what can we do?  Can we just get them to sleep more?  Instead of eight hours of sleep at night, why donít we get them to do ten hours sleep a night?

Ullrich - Unfortunately, itís not that easy because you need the right type of sleep.  So, as we said, there are different stages and stages and sleep spindles are particularly characteristic of that particular sleep stage.  In the case of schizophrenics, there are other things that we could do, so we could make the sleep more continuous.  Most schizophrenics will have fragmented sleep but also we could try and bring back some of the missing oscillation, if you will, so there might be a way of using pharmacology.  The right pharmacology (the right sleeping pills) to bring back the right oscillations during sleep.  Another promising concept for enhancing oscillations during sleep is actually electrical stimulation or magnetic stimulation.  A recent technology has emerged where people can use magnetic pulses, which is called transcranial magnetic stimulation, to actually induce activity patterns of brainwaves in brains of healthy people but also itís beginning to be used in clinical populations.

Connie - Clearly sleep and memory are intrinsically combined, impossible to separate but what about the rest of us.  I asked our sleep expert for a few tips.

Ullrich - If you have to take in a lot of information and you have to remember it the next day, itís probably good to have either have individual naps in between in the afternoon,  so that will definitely help your brain to pack the influx of information nicely.

Connie - Individual naps between study; Who knew that students had it right all along!

Ullrich - Yes, they were doing the right thing and especially the young brains need even more sleep than the older brains.

Connie - Iíll tell my boss and start petitioning to get beds put in at work.

Ullrich - Yes, well if only.  I would be happy to sign a letter if you need some support.


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