What’s so special about adolescence?

It turns out that adolescence marks a critical crossroad between brain maturation and mental illness. Adolescence is usually defined as starting at puberty (around age 10) and ending at the cultural definition of adulthood, 18 years old. Most people start presenting symptoms and get diagnosed with a mental illness during adolescence. This is happening at a time when the last major brain region to mature, the frontal lobe, is going through a burst of development.

Contrary to what you would expect, maturation of the frontal lobe during this time period is reflected by brain volume decreasing. This decrease happens because connections between the frontal lobe and the rest of the brain are being pruned. It’s similar to what gardeners do to their plants, where they remove unhealthy or useless branches so that plant growth is focused on regions that need it. In the case of brain maturation, pruning improves the efficiency of communication between regions by using experience to remove redundant or unused connections. The increase in efficiency makes it easier and faster to use the functions of the frontal lobe, as you have less competing information interfering from other places.

Dr. Karpov's fellowship is under the supervision of Dr. Ryan J. Herringa (former mentor) and Prof. Rasmus M. Birn (current mentor) in UW-Madison's Department of Psychiatry.