Thursday, April 2, 2009

We Sleep to Prune the Brain

In the process of caring for plants for many years (I collect orchids and bromeliads), I've found a number of parallels between their lives and mine. For example, their overall health can change rapidly for the worse, but only long-term, consistent, persistent attention and cultivation will result in an exemplary speciman. I've the same is true with my own health - it takes months of consistent attention to diet, exercise, sleep, and stress to feel truly excellent.

So it was with some interest that I ran across this research that suggests sleep is designed to prune the brain of unneeded synapses:
Sleep's core function, Cirelli and Tononi say, is to prune the strength or number of synapses formed during waking hours, keeping just the strongest neuronal connections intact. Synapse strength increases throughout the day, with stronger synapses creating better contact between neurons. Stronger synapses also take up more space and consume more energy, and if left unchecked, this process—which Cirelli and Tononi believe occurs in many brain regions—would become unsustainable.2,3 Downscaling at night would reduce the energy and space requirement of the brain, eliminate the weakest synapses, and help keep the strongest neuronal connections intact. This assumption is based on the principle in neuroscience that if one neuron doesn't fire to another very often, the connection between the two neurons weakens. By eliminating some of the unimportant connections, the body, in theory, eliminates background connections and effectively sharpens the important connections.
Cool stuff!

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