Is pulling an all-nighter a wise idea?
Dr Matthew Walker conducted a study, him and his team took a large group of individuals and assigned them to either a sleep group or a sleep deprivation group. Both groups remained awake normally across the first day.
Across the following night, those in the sleep group obtained a full night of shut-eye, while those in the sleep deprivation group were kept awake all night under the watchful eye of trained staff in my lab.
Both groups were then awake across the following morning. Around midday, we placed participants inside an MRI scanner and had them try to learn a list of facts, one at a time, as we took snapshots of their brain activity.
Then they tested them to see how effective that learning had been. However, instead of testing them immediately after learning, they waited until they had had two nights of recovery sleep.
They did this to make sure that any impairments we observed in the sleep-deprived group were not confounded by them being too sleepy or inattentive to recollect what they may very well have learned. Therefore, the sleep-deprivation manipulation was only in effect during the act of learning, and not during the later act of recall.
When they compared the effectiveness of learning between the two groups, the result was clear:
There was a 40 percent deficit in the ability of the sleep-deprived group to cram new facts into the brain (i.e., to make new memories), relative to the group that obtained a full night of sleep.
To put that in context, it would be the difference between acing an exam and failing it miserably! What was going wrong within the brain to produce these deficits?
They compared the patterns of brain activity during attempted learning between the two groups, and focused their analysis on the hippocampus—the information “in-box” of the brain that acquires new facts.
There was lots of healthy, learning-related activity in the hippocampus in the participants who had slept the night before. However, when they looked at this same brain structure in the sleep-deprived participants, they could not find any significant learning activity whatsoever.
It was as though sleep deprivation had shut down their memory in-box, and any new incoming information was simply being bounced. You don’t even need the blunt force of a whole night of sleep deprivation.
Simply disrupting the depth of an individual’s NREM sleep with infrequent sounds, preventing deep sleep and keeping the brain in shallow sleep, without waking the individual up will produce similar brain deficits and learning impairments.
Next time you thinking of pulling an all nighter, think again!