Sleeping Half the Night Is Worse for Memory and Learning Consolidation Than No Sleep at All

Sleep is super important for consolidating memories and new research has shown that sleep deprivation interferes with learning and memory, which are two critical functions of your brain.

A newly released study looked at how sleep deprivation affects your brain function and according to Science Daily, found it can actually hijack your ability to unlearn fear-related memories.

A team of researchers led by Anne Germain, PhD, at the University of Pittsburgh and Edward Pace-Schott, PhD, at Harvard Medical School and Massachusetts General Hospital, used a sleep laboratory to study 150 healthy adults.

One-third of the participants were allowed to sleep normally, while one-third were sleep restricted (meaning they slept for the first half of the night) and the remaining one-third were sleep-deprived and got no sleep at all.

The next morning, all participants underwent fear conditioning to examine the effect of sleep or lack thereof, would have on each person. This included a ‘fear extinction’ exercise, where subjects were shown three colours, two of which included an electric shock.

Following this exercise, participants then underwent fear extinction which involved showing them one of the colours without any electric shocks, in order to learn that that particular colour was now considered “safe”.

The participants were tested again later that night and shown all three colours again in order to measure their fear extinction recall — basically how well they had “unlearned” the threat of the colour. During these exercises, brain images were recorded to show activation in brain areas associated with emotional regulation.

“We found that among the three groups, those who had only gotten half a night’s sleep showed the most activity in brain regions associated with fear and the least activity in areas associated with control of emotion,” said Dr Pace-Schott.

Somewhat surprisingly, the participants who had no sleep at all lacked the “brain activation” in the fear-related areas during both conditioning and extinction exercise. During the recall activity, their brains actually looked more similar to those who had had a full night of sleep.

The data seems to suggest that those who have had half a night of sleep were worse off than those who didn’t sleep at all. The researchers seem to think this is because sleeping only half the night results in a loss of rapid eye movement (REM) sleep, which is important for consolidating memories. REM usually occurs during the end of a normal sleep period.

According to Dr Carter, this research used “noninvasive brain imaging to give us a novel window into how sleep deprivation disrupts the normal fear extinction mechanisms and potentially increases vulnerability to posttraumatic stress symptoms.”

“Medical workers and soldiers often have curtailed or interrupted sleep rather than missing an entire night’s sleep,” Dr Pace-Schott said. “Our findings suggest that such partially sleep-deprived individuals might be especially vulnerable to fear-related conditions such as posttraumatic stress disorder.”

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