The brain tags important events during learning with special theta rhythms to preserve them during sleep, reports infohub.kz.
Researchers at York University, led by Dan Denis, studied the neural mechanisms that help the brain select events for consolidation into long-term memory. In an experiment involving 31 participants, scientists used electroencephalography to record brain activity while participants memorized associations between words and images.
They found that paired associations accompanied by theta oscillations at a frequency of 3–8 Hz during learning were significantly better retained in memory after sleep. During sleep, these theta rhythms improved the interaction between slow neural oscillations and sleep spindles—brief bursts of brain activity.
The researchers note that such a filter prevents the brain from being overloaded with unnecessary information. Understanding the mechanisms of memory selection could aid in studying mental disorders such as depression, where people tend to remember negative events while ignoring positive experiences. The results were published in the journal PLOS Biology.