New study shows how seals sleep with only half their brain at a time

(Medical Xpress)—A new study led by an international team of biologists has identified some of the brain chemicals that allow seals to sleep with half of their brain at a time.

The study was published this month in the and was headed by scientists at UCLA and the University of Toronto. It identified the that allow the seal brain to remain half awake and asleep. Findings from this study may explain the biological mechanisms that enable the brain to remain alert during waking hours and go off-line during sleep.

"Seals do something biologically amazing—they sleep with half their brain at a time. The left side of their brain can sleep while the right side stays awake. Seals sleep this way while they're in water, but they sleep like humans while on land. Our research may explain how this unique happens" said Professor John Peever of the University of Toronto.

The study's first author, University of Toronto PhD student Jennifer Lapierre, made this discovery by measuring how different chemicals change in the sleeping and waking sides of the brain. She found that acetylcholine – an important brain chemical – was at low levels on the sleeping side of the brain but at high levels on the waking side. This finding suggests that acetylcholine may drive brain alertness on the side that is awake.

But, the study also showed that another important – serotonin - was present at the equal levels on both sides of the brain whether the seals were awake or asleep. This was a surprising finding because scientist long thought that was a chemical that causes brain arousal.

These findings have possible human health implications because "about 40% of North Americans suffer from and understanding which brain chemicals function to keep us awake or asleep is a major scientific advance. It could help solve the mystery of how and why we sleep" says the study's senior author Jerome Siegel of UCLA's Brain Research Institute.

More information: www.csb.utoronto.ca/faculty/pe… sleep-implications-n

Related Stories

Study: Brain injuries tied to trouble sleeping

May 24, 2010

People with brain injuries may produce low amounts of melatonin, which affects their sleep, according to a study published in the May 25, 2010, print issue of Neurology, the medical journal of the American Academy of Neu ...

Recommended for you

After watching disturbing video, CPAP usage soars

Sep 25, 2014

Like more than 20 million other Americans, John Brugger has been diagnosed with sleep apnea. He snored, tossed and turned and struggled to breathe during the night, which often left him not only exhausted ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.