Evidence for a widespread dopaminergic innervation of the human cerebral neocortex

The recent finding that D1 dopamine receptors are present in all neocortical areas of the human brain, does not fit in with the generally held view that the mesocortical dopaminergic pathway is restricted to prefrontal areas. We investigated the brains of 3 patients who died with a unilateral infarction in the ventral midbrain, including the substantia nigra and ventral tegmental area. Compared to the intact side, the D1 receptors in frontal, temporal, parietal and occipital cortices and caudate nucleus at the lesioned side were increased by 27-37%, which is consistent with an up-regulation in response to a depletion of dopamine. These data provide evidence for a more widespread dopaminergic innervation of the human neocortex.