Pubescent rats were more likely to extend their bodies into the anxiety-provoking areas than prepubescent rats. Adult rats demonstrated similar extension behaviors, but did not enter the anxiety-provoking areas, while the pubescent animals abruptly entered the areas after assessing risk, suggesting that the pubescent rats were more impulsive than the adults. No sex differences were found at any age.

"Puberty appears to be a specialized stage of development in which males and females are more likely to explore novel environments," Hodes says. "This is likely an adaptive strategy that emerges with foraging behavior. It would also have reproductive advantages by enhancing contact with new members of the opposite sex."

In other work, scientists are using the extreme example of risk-taking among psychopaths to elucidate normal behavior and brain structure and function. Prominent characteristics of psychopaths are their poor decision-making ability and heightened risk taking.

Diana Fishbein, PhD, and her colleagues at the Research Triangle Institute International in Baltimore scanned the brains of 13 psychopaths and 15 nonpsychopaths using positron emission tomography (PET) while the individuals completed two sets of trials from a computerized neurocognitive task--the Rogers Decision-Making Task (RDMT). Before being scanned, the participants scored in either the "primary psychopathy" or nonpsychopathy ranges on a questionnaire that measures psychopathic characteristics.

The computerized RDMT measures risk-taking tendencies and decision-making ability by presenting participants with various choices that involve "gambling" a certain number of points based on the likelihoo
'"/>

Contact: Leah Ariniello
dawn@sfn.org
202-462-6688
Society for Neuroscience
24-Oct-2004