New evidence on biological basis of highly impulsive, aggressive behaviors

Today's new findings show that:

• The absence of serotonin receptors during early development leads to highly aggressive and impulsive behaviors in mice. Impulsivity, but not aggression, returns to normal levels by reintroducing the receptors
• Adolescents react more impulsively to danger than adults or children, and the prefrontal cortex works harder to exert control over impulsive responses to threatening cues

Other recent findings discussed show that:

• Weak control of the brain's prefrontal cortex (which monitors personality, decision-making, and self-restraint) over regions associated with reward and motivation could explain the lack of self-control experienced by anti-social individuals
• Criminal defendants increasingly use brain science to explain their actions, pointing to brain scans and the scientific literature for evidence that brain impairments affect behavior. This is impacting how the legal system assigns responsibility and punishment for criminal wrongdoing in the United States

"Our deeper understanding of the origins of delinquent behavior can be a double-edged sword," said press conference moderator BJ Casey, PhD, of Weill Cornell Medical College, an expert in attention, behavior, and related brain disorders. "While we're making tremendous gains in neuroscience that should lead to improved treatments, our biological insights also have implications for criminal cases and the judicial process that we need to understand."