http://www.sciencemag.org/content/350/6264/1052.1.full
Science
27 November 2015:
Vol. 350 no. 6264 p. 1052
DOI: 10.1126/science.350.6264.1052-a
Vol. 350 no. 6264 p. 1052
DOI: 10.1126/science.350.6264.1052-a
- Editors' Choice
More neurons mean less need for sleep
Sleep is seemingly universal among
animals. Daily sleep time varies considerably between mammalian species
and also during
mammalian development, yet we still don't know what
drives this variation. Herculano-Houzel hypothesized that
sleep-inducing
metabolites produced during waking hours accumulate
more slowly in brains that have a smaller density of neurons underneath
a unit surface area that gets washed by
cerebrospinal fluid during waking. In 24 mammalian species and several
postnatal stages
in the developing rat, there was indeed a
correlation between the ratio of neuronal density to brain surface area
and daily
sleep duration. The evolutionary addition of
neurons may have decreased the need for sleep, allowing a species to
feed for
longer, and thus facilitated further increases in
neuronal numbers.
Proc. R. Soc. London Ser. B 282, 1816 (2015).
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