How deep sleep consolidates recent memories

New York: A team of US researchers has for the first time decoded how deep sleep -- also called slow-wave sleep -- is involved in promoting the consolidation of recent memories in our brain.

Earlier research strongly suggested that sleep, which constitutes about a third of our lives, is crucial for learning and forming long-term memories. But how such memory is formed has not been well understood.

The new study by researchers at University of California-Riverside tried to answer this question using a computational model.
During sleep, human and animal brains are primarily decoupled from sensory input.

The brain, however, remains highly active, showing electrical activity in the form of sharp-wave ripples in the hippocampus part of the brain and large-amplitude slow oscillations in the cortex region.

Traces of episodic memory acquired during wakefulness and initially stored in the hippocampus are progressively transferred to the cortex as long-term memory during sleep.

The team's model, presented recently in the Journal of Neuroscience, showed that patterns of slow oscillations in the cortex are influenced by the hippocampal sharp-wave ripples and that these patterns of slow oscillations determine synaptic changes in the cortex.