The development of the Cerebral Cortex during adolescence seem to reload the main stages of human brain Evolution. The suggestion comes from a study conducted by researchers at the Penn University in Philadelphia and recently published in the authoritative scientific journal PNAS.

Brain plasticity and adolescence

Neural circuits are constantly remodeled by genetic and environmental factors. For instance, after birth, synaptic connections are pruned in order to eliminate redundant contacts between neurones. On the other hand, every time one learns something new, specific patterns of connectivity within brain circuits change accordingly.

Neuroscientists call this phenomenon neural or brain plasticity.

Although brain plasticity is active throughout the entire life, it is particularly evident during adolescence and specifically involves the cerebral cortex. However, the overall picture of brain plasticity processes occurring in teenagers is still blurry as the available studies were carried out in small populations and didn't look at the whole cerebral cortex.

Plasticity of the cerebral cortex and evolution

Researchers at Penn University exploited a neuroimaging technique that is able to measure anatomical parameters over the whole cerebral cortex. "The method is named non-negative matrix factorization" says Christos Davatzikos, professor of radiology and leading author of the paper "and we used it to identify patterns of cortical development in about one thousand children and teenagers".

This way, neuroscientists led by Christos Davatzikos found that associative cortical areas, which integrate information from different sources, are thicker in males before the age of 20 years. After this age the cortical thickness in the same areas is higher in females.

Researchers also found that sensory and motor cortical areas develop earlier than associative areas, which are at hierarchically higher levels of cortical information processing and were the latest to expand during evolution.

These findings suggest that during adolescence the cerebral cortex develop according to a timeline that closely retraces the main stages of human brain evolution. Notably, the study provides a new tool to track changes during the development of the human brain and to detect deviations that can lead to psychiatric or neurological disorders.