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Brain activity during sleep is affected by experiences, genetics

A new study published by the Society for Neuroscience has demonstrated that some of the patterns generated by the brain’s electrical activity during sleep are driven by genetics, while others are shaped by our environment.

Identifying how an individual’s biology or personal experience contributes to sleep neurophysiology could ultimately be used to develop new therapies for psychiatric disorders which notably alter the brain’s activity while the body is at rest.

The study was designed to allow the researchers to distinguish between the influence of genetic and environmental factors during the most crucial phases of sleep.

A research team led by Leila Tarokh used electroencephalography (EEG) to measure the brain activity of 11- to 14-year-old pairs of identical and fraternal twins throughout two consecutive nights of sleep at home.

During stage 2 of light sleep, sudden bursts of brain activity occur that are referred to as sleep spindles because of how they look when printed out on an EEG reading. Stage 2 sleep, which usually lasts about 20 minutes, is characterized by a decrease in heart rate and in temperature as the body prepares itself for deep sleep.

The next phase of sleep is known as slow-wave sleep (SWS), the deepest phase of non-rapid eye movement (NREM) sleep. Phase 3 sleep is considered to be important for memory consolidation, and is characterized by delta waves on an EEG reading.

The experts discovered that both hereditary and environmental factors influenced slow waves and spindles among the study participants. The extent of the impact of genes or the environment on electrical activity depended on the brain region being monitored. Frontal regions were found to be under strong environmental influence, while regions toward the back of the brain were strongly influenced by genetics.

The study is published in the Journal of Neuroscience.

By Chrissy Sexton, Staff Writer

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