Risk-taking behaviour in teens is caused by imbalanced brain activity

18th Oct 2016

Adolescents are more likely to engage in heightened risk-taking behaviour compared to humans and non-humans alike. A new study published in Current Biology demonstrates a potential causal relationship between behavioural control and a specific imbalance in brain function that exists during the teen years.

This imbalance in activity is between the prefrontal cortex, PFC (area of the brain involved in cognitive control and inhibition) and the nucleus accumbens, NAC (plays a role in the reward-seeking and addiction). The imbalance can arise from reduced engagement of the PFC or from excessive activity in NAC.

The study used a method called Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) to stimulate the imbalance that take place during adolescents in adult rats. This method allows the researchers to remotely control the activity of brain cells. 

The rats learnt an inhibition task, where a tone presented by itself signalled a food reward would be delivered. However, a light preceding the tone indicated no food. When the DREADDs were activated in both the PFC and NAC, creating an imbalance, the rats exhibited a dramatic delay in learning this inhibitory task. This delay also matched the delay seen in adolescent rats in an earlier study. 

These findings illustrate how this form of proactive inhibition is age-dependent, which is consistent with previous work. Understanding specific brain function changes during development relate to behaviour is critically important for determining why some individuals engage in excessive risk-taking behaviour.

To read the full article, please visit Science Direct website