Brain cells responsible for bravery found in the hippocampus

Sept. 7 (UPI) -- How do daredevils keep their nerve?

New research suggests risk-takers maintain their poise with the help of "bravery cells," found in the brain's hippocampus.

Through a series of experiments using mice, scientists found OLM cells, when stimulated, triggered a brain rhythm called Type 1 theta oscillations. The unique brain rhythms have previously been observed in the brains of animals who feel secure in dangerous environs.

For example, an animal sufficiently hidden from a lurking predator might feel safe despite the predator's close proximity. Research suggests the brain rhythm prevents the natural fight or flight system from dictating behavior. Fleeing the oblivious predator could put an animal in unnecessary danger.

In humans, an inability to properly produce Type 1 theta oscillations could explain a variety of anxiety disorders. Humans with chronic or acute anxiety are often risk-averse.

Physicians and psychiatrists most frequently treat anxiety disorders with antidepressants. Because the drugs treat the entire brain, they sometimes yield unwanted side-effects.

The latest research, published this week in the journal Nature Communications, could help researchers development anxiety treatments for specific portions of the brain.

Scientists have previously identified "anxiety cells" inside the brains of mice. OLM cells may help keep anxiety neurons in check.

The study also showed OLM cells can be influenced by drugs. The neurons are especially sensitive to nicotine.

"This finding may explain why people binge-smoke when they are anxious," Richardson Leao, researcher at the Brain Institute of the Federal University of Rio Grande do Norte, said in a news release.

Historically, neuroscientists have focused on the hippocampus' role in memory and cognition. But a growing body of research suggests the brain region also helps control emotions.

"It is fascinating how different regions of the same brain structure control distinct behaviors and how they interact with each other," said Sanja Mikulovic, a researcher at Uppsala University. "Identifying specific circuits that underlie either cognitive or emotional processes is crucial for the general understanding of brain function and for more specific drug development to treat disorders."