Many cognitive processes depend on the dorsolateral prefrontal cortex, the convex outer portion of the frontal lobe. The neurotransmitter dopamine is critical to many of these functions, but apparently not all. The amount of dopamine in the prefrontal cortex is affected by the gene for the catechol-
O-methyltransferase enzyme, because a mutation substituting the amino acid methionine (Met) for valine (Val) increases dopamine specifically in the prefrontal cortex. Diamond et al. (p.
125) found that healthy children with the Met-Met genotype scored higher than children with the Val-Val genotype on a task that depends on both the dorsolateral prefrontal cortex and dopamine. Scores were similar, however, for a task that also depends on the dorsolateral prefrontal cortex but is apparently unaffected by dopamine and for tests depending on other brain regions. This differential sensitivity may be useful in developing specialized medications.
+