The quality of deep sleep can influence the brain’s ability to cope with stressful social situations, according to an international study conducted in rats and published by the Society for Neuroscience.
The researchers analyzed the role of the prelimbic cortex, a region of the brain involved in contextualizing emotional responses. During the experiment, male rats were placed in the cages of rats considered “aggressors,” in daily five-minute sessions, for five days, to induce social stress situations. The sleep quality of the animals was monitored throughout the experiment, and subsequently the researchers analyzed brain activity.
The results show that alterations in activity of the prelimbic cortex during non-REM sleep, particularly during slow-wave sleep — associated with deep sleep — were related to the animals’ ability to withstand and recover from stressful situations.
Suppression of neuronal activity in the prelimbic cortex during sleep, a characteristic of this state, allowed predicting which rats showed greater resilience to stressful experiences. After these experiences, the researchers also observed a reorganization of neuronal activity in this region of the brain, with a redistribution of the firing rates of neurons.
“The quality of sleep appears to determine how the prelimbic cortex suppresses emotional responses, which we think is represented by the firing rate of neurons,” explains Christopher Ehlen of Morehouse School of Medicine, cited by the organization. The researcher adds that animals more susceptible to stress may not sleep as deeply, whereas in the more resilient ones, deep sleep may allow maintaining an active response to stress.
The team now plans to assess whether sleep deprivation in resilient rats alters neuronal activity in the prelimbic cortex. The researchers also hope that these results may contribute to future human studies aimed at identifying neurobiological markers associated with resilience or vulnerability to stress.
