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Sleep not just protects memories against forgetting, it also makes them more accessible

neuroscience Sleep makes our memories more accessible

Sleeping not only protects memories from being forgotten, it also makes them easier to access, according to new research from the University of Exeter and the Basque Centre for Cognition, Brain and Language. The findings suggest that after sleep we are more likely to recall facts which we could not remember while still awake.

In two situations where subjects forgot information over the course of 12 hours of wakefulness, a night’s sleep was shown to promote access to memory traces that had initially been too weak to be retrieved.

The research tracked memories for novel, made-up words learnt either prior to a night’s sleep, or an equivalent period of wakefulness. Subjects were asked to recall words immediately after exposure, and then again after the period of sleep or wakefulness.

The key distinction was between those word memories which participants could remember at both the immediate test and the 12-hour retest, and those not remembered at test, but eventually remembered at retest.

The researcher found that, compared to daytime wakefulness, sleep helped rescue unrecalled memories more than it prevented memory loss.

“Sleep almost doubles our chances of remembering previously unrecalled material. The post-sleep boost in memory accessibility may indicate that some memories are sharpened overnight.”

“This supports the notion that, while asleep, we actively rehearse information flagged as important. More research is needed into the functional significance of this rehearsal and whether, for instance, it allows memories to be accessible in a wider range of contexts, hence making them more useful,” Nicolas Dumay of the University of Exeter explains.

The beneficial impact of sleep on memory is well established, and the act of sleeping is known to help us remember the things that we did, or heard, the previous day. The idea that memories could also be sharpened and made more vivid and accessible overnight, however, is yet to be fully explored.

Dr Dumay believes the memory boost comes from the hippocampus, an inner structure of the temporal lobe, unzipping recently encoded episodes and replaying them to regions of the brain originally involved in their capture – this would lead the subject to effectively re-experience the major events of the day.

Dumay, N (2015). Sleep not just protects memories against forgetting, it also makes them more accessible Cortex : http://hdl.handle.net/10871/17864

2 responses

  1. Zack

    Sleep is an amazing thing. It is so cool that it has such an effect on more than just how much energy we have the next day. We live in a go go go culture where sleep is so often something that is replaced by caffeine and people freak out about little things. If everyone just slowed down a little bit and allowed themselves a little more sleep than they get, maybe their lives would improve. Scratch that maybe… Their lives would get better. All of our body needs sleep.


    July 26, 2015 at 6:01 pm

    • It’s funny you bring up the caffeine thing, I think modern pace is far too fast for people to keep up with and that leads us to think we can just do away with sleep in favor of a chemical solution. Hopefully things will come around full circle and one day we will think it’s funny that at this little blip in time people didn’t think they needed sleep or had to work so hard in order to make something of themselves.


      July 27, 2015 at 12:44 pm

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