Dopamine activity in the occipital and temporal cortices of rats: dissociating effects of sensory but not pharmacological stimulation.

Little is known about the functional role of DA in other cortical areas than in the prefrontal cortex. Here we demonstrate that visual stimulation increases DA activity as measured by in vivo microdialysis in the occipital, but not in the temporal cortex of freely moving rats. Auditory stimulation neither acutely affected DA in the occipital nor in the temporal cortex. A pharmacological challenge with cocaine (0, 5, 10, 20 mg/kg; i.p.) increased DA levels in both areas dose-dependently. These data suggest that DA might play a role in visual processing selectively in the occipital cortex. Furthermore, the results indicate that DA in both regions may contribute to cocaine's behavioral effects.