Mar 28, 2011 07:20 GMT  ·  By

People who do not get enough sleep each night are at increased risk of suffering from short-term euphoria, impaired decision-making abilities and an urge to engage in risky behaviors, experts say.

The new work, which was carried out by experts at the Harvard Medical School and the University of California in Berkeley (UCB), reveals the changes that take place in the human brain as people lose a night's sleep.

In a set of experiments, volunteers were asked to stay awake for a night, all while the researchers were investigating their neural circuitry via specialized imaging methods. The team learned that the pleasure pathways in the brain misfired when the participants got insufficient sleep.

But the team says that the nerve centers underlying pleasure and euphoria are also those that make people engage in risky behaviors. “When functioning correctly, the brain finds the sweet spot on the mood spectrum,” explains Dr. Matthew Walker.

“But the sleep-deprived brain will swing to both extremes, neither of which is optimal for making wise decisions,” adds the expert, who is an UCB associate professor of psychology and neuroscience. Walker is also the lead author of the new study.

Those who work in critical professions and circumstances should therefore be more attentive to their sleeping patterns, the researcher and his team explain. These people simply cannot afford to be tired.

“We need to ensure that people making high-stakes decisions, from medical professionals to airline pilots to new parents, get enough sleep,” Walker explains.

“Based on this evidence, I’d be concerned by an emergency room doctor who’s been up for 20 hours straight making rational decisions about my health,” he goes on to say, quoted by PsychCentral.

According to the paper the team published in the latest issue of the Journal of Neuroscience, regions in the frontal lobe of the brain are strongly connected to the dopamine reward regions in the cortex only after people sleep for sufficient amounts of time.

When this doesn't happen, the connection fails, and risk behaviors may ensue. The researchers conducted their investigations by using functional magnetic resonance imaging (fMRI).

The technique can be used to analyze blood flow and activation patterns in the human brain. This hints at the areas of the brain that are involved in certain processes – such as risky behaviors – that experts are interested in.