A lot changes during adolescence, and the brain is no exception.  There are 3 main processes are supposed to occur during adolescence:

  1. New brain connections are created.
  2. Some connections are no longer needed.  These connections are destroyed.
  3. Make neural transmissions faster, which increases the ‘speed’ of thinking.

These 3 processes all aim to make the brain more efficient.

Below is a MRI scan of a typical brain.

Image courtesy of TheBrain (2005)