As little as a few hours of lost sleep may greatly impair memory and learning, according to research presented at the Society for Neuroscience meeting in New Orleans this week.
A growing body of evidence suggests that sleeping may play an important role in memory formation, but exactly how sleep helps us remember has been unclear. To study this, scientists have been investigating how sleep deprivation alters brain function.
One team of researchers from Pennsylvania, for example, studied the effects of a single night of lost sleep on 22 healthy adults who agreed to stay in the lab for 5 days and undergo brain imaging and memory testing. The participants were first tested after a normal night of sleep, then after a night of sleep deprivation, and once again after 2 nights of recovery sleep. They found that participants performed more poorly on memory tasks after a lost night of sleep and that connectivity was perturbed between the brain’s hippocampus (which plays a role in memory and other functions) and default mode network (a network of brain areas thought to play a role in self-perception and day dreaming). The good news, however, was that these brain connections and the participants’ performance on memory tasks were back to normal after a couple nights of recovery sleep, according to Hengyi Rao, PhD, of the University of Pennsylvania, who discussed the findings during a press briefing Tuesday.
Giulio Tononi, MD, PhD, of the University of Wisconsin in Madison, reviewed findings from animal studies suggesting that we are compelled to sleep in order to preserve our ability to learn. The need for the brain to rest is so great that in sleep-deprived individuals, parts of the brain will briefly go to sleep, which can lead to an individual making mistakes.
“While we think we are awake, some parts of our brain are asleep,” he explained.