Seals may reveal secret of sleep
2013-02-21 15:47
Ottawa - Scientists have identified brain chemicals that
allow seals to sleep with half of their brain at a time, according to a study
published in the Journal of Neuroscience.
And they say the discovery of how what they called a
"unique biological phenomenon" works may help millions - including an
estimated 40% of North Americans - who suffer from insomnia or other sleep
disorders.
"It could help solve the mystery of how and why we
sleep," said the study's senior author Jerome Siegel of UCLA's Brain
Research Institute.
Co-author John Peever of the University of Toronto
explained that seals are able to "something biologically amazing... The
left side of their brain can sleep while the right side stays awake."
The animals sleep this way while they're in water, but
they sleep like humans while on land, he said.
Scientists measured how chemicals change in the sleeping
and waking sides of a seal's brain, using surface scanners to measure brain
electrical activity and tubes inserted in the cortex to measure chemicals.
Acetylcholine was found at low levels on the sleeping
side of the brain but at high levels on the waking side, suggesting that it may
drive brain alertness on the side that is awake.
Another important brain chemical - serotonin - was
present in equal levels on both sides of the brain at all times.
This is surprising, said Peever, because scientists long
thought serotonin was a chemical that causes brain arousal.
