The teens who had been drinking heavily for 1-2 years could do the exercises as well as those who had never drank, although their parietal cortex was much more active. 

Teens who had been drinking heavily for 3-4 years performed worse on the tasks; activity in other brain regions—those involved in vision (occipital lobes) and motor control (motor cortex)—declined.

The longer a teen had been drinking, the harder the brain worked, whereas in the nondrinkers the regions expended less energy as the teen matured.

      -drinkers' brains had to exert unusual  

      effort to perform the tasks.

Seventh Study

Lindsay M. Squeglia reported similar findings to the last study on spatial working memory.

While in a brain scanner, 55 nondrinkers and 40 heavy drinkers 16-19 years old tried to recall shapes they had previously been shown.

Results:

Therefore:

Squeglia suggests that when adolescents  start drinking, the brain works harder to keep up but over time it can no longer compensate, and performance drops.