How seals sleep with only half their brains – study

Wednesday 20th February 2013

An international team of biologists have identified some of the brain chemicals that allow seals to sleep with half of their brain at a time. Their brain allows the left side of their brain to sleep while the right side stays awake. They sleep this way while they're in water, but they sleep like humans when they’re on land.

The study published this month in the Journal of Neuroscience was led by scientists at UCLA and the University of Toronto. They made the discovery by measuring how different chemicals change in the sleeping and waking sides of the brain.

The results from the tests found that acetylcholine – an important chemical in the brain – was at low levels on the sleeping side of the brain but at high levels on the waking side. This suggests that acetylcholine may drive brain alertness on the side that is awake. The study also showed that another important brain chemical, serotonin was present at equal levels on both sides of the brain at all times. This is surprising as scientists have always thought that serotonin was a chemical that causes brain stimulation.

Tags: sleep study research seals brain chemical

Category: Sleep Research

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