What do stock traders, doctors and soldiers have in common? Each often needs to make important decisions on little sleep.

Michael Chee of the Duke-NUS Graduate Medical School in Singapore and his colleagues used brain imaging to study how sleep deprivation affects decision-making. They scanned the brains of healthy adults performing a complicated gambling task. When the volunteers had stayed up all night, their strategy shifted towards seeking bigger gains over protecting against losses. The shift in behaviour correlated with changes in brain activity in regions previously associated with reward evaluation and regret.

Interestingly, the shift in strategy did not correlate with vigilance, suggesting that although stimulants such as caffeine might make sleepy people more alert, they do not improve decision-making abilities.

J. Neurosci. 31, 3712–3718 (2011)