Studies of adolescent brain development tell us that it is not just the child’s body that changes dramatically in puberty – the extent of rewiring that takes place in the human brain during this period is comparable only with what happens in the first years of life.
There is strong consensus amongst developmental neuroscientists about the nature of these changes. Four specific structural changes in the brain are noteworthy:
Decrease in grey matter in the prefrontal cortex
There is a decrease in grey matter in the prefrontal cortex in early adolescence, with unused connections between neurons being ‘pruned’. This period, characterised by major improvements in cognitive abilities and logical reasoning, begins just before puberty and is largely complete by mid-adolescence.
This may explain why the adolescent’s capacity for intellectual work appears to significantly slow down with the onset of puberty, and then picks up again midway through adolescence.
Gradual and continuous increase in white matter in the prefrontal cortex
There is a gradual and continuous increase in quantities of white matter in the prefrontal cortex throughout adolescence. White matter helps connections between neurons to take place. Higher-order cognitive functions such as planning ahead, weighing risk and reward, and making complicated decisions depend on these more effective connections. This process of improving brain connections continues through late adolescence and is only complete in early adulthood.
Adolescents want to make real and meaningful decisions that impact on their life: it is up to us to give them opportunities to do so, or they may create these for themselves and perhaps not always in the most appropriate ways.
Strengthening of connections between limbic system and prefrontal cortex
There is a gradual and continuous increase in the strength of the connections between the limbic system (emotions) and the prefrontal cortex (decisions). This means that very strong feelings are less likely to be modulated by the involvement of brain regions related to impulse control, forward planning, and cost-benefit analysis. The impact of peer-pressure is highest in early adolescence but steadily decreases as the adolescent matures.
Adolescents need adults and stable older peers as role models in their lives. Knowing that it is natural for adolescents to look outside their family for these resources means we would be wise to put them in contact with a range of adults and a peer group whom we are happy for them to spend time with.
More dopamine-related activity than ever before
There are substantial changes in density and distribution of dopamine receptors (pleasure) in the pathways between the limbic system (emotions) and the prefrontal cortex (decisions). There is more dopamine-related activity during early adolescence than at any other point in human development.
This may explain the mechanism through which emotions and feelings start to play a significant role in their day-to-day lives. It also underlines the need for an educational approach that is built around tangible goals the adolescents can relate to and connect with.