posted from: https://www.theguardian.com/science/neurophilosophy/2017/feb/03/sleep-may-help-us-to-forget-by-rebalancing-brain-synapses
New research provides evidence for the idea that sleep restores cellular homeostasis in the brain and helps us to forget irrelevant information
We spend one third of our lives sleeping, but we still do not know exactly why we sleep. Recent research shows that that the brain does its housekeeping while we sleep, and clears away its waste. According to another hypothesis, sleep plays the vital role of restoring the right balance of brain synapses to enhance learning, and two studies published in today’s issue of Science now provide the most direct evidence yet for this idea.
We do know that sleep is important for consolidating newly formed memories. During waking hours, we learn all kinds of new information, both consciously and unconsciously. To store it, the brain modifies large numbers of synaptic connections, making some of them stronger and larger, and it’s now thought that as we sleep other synapses are weakened or destroyed, so that the important new information is stored for later use, while irrelevant material, which could interfere with learning, is not.
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