Abstract
Prefrontal cortex (PFC) is believed to play a crucial role in executive control of cognitive functions. Part of this control is thought to be achieved by control of sensory signals in posterior sensory cortices. Dopamine is known to play a role in modulating the strength of signals within the PFC. We tested whether this neurotransmitter is involved in PFC’s top-down control of signals within posterior sensory areas. We recorded responses of neurons in visual cortex (area V4) before and after infusion of the D1 receptor (D1R)-antagonist SCH23390 into the frontal eye field (FEF) in monkeys performing visual fixation and saccadic target selection tasks. Visual stimuli were presented within the shared response fields of simultaneously studied V4 and FEF sites. We found that modulation of D1R-mediated activity within the FEF enhances the strength of visual signals in V4 and increases the monkeys’ tendency to choose targets presented within the affected part of visual space. Similar to the D1R manipulation, modulation of D2R-mediated activity within the FEF also increased saccadic target selection. However, it failed to alter visual responses within area V4. The observed effects of D1Rs in mediating the control of visual cortical signals and the selection of visual targets, coupled with its known role in working memory, suggest PFC dopamine as a key player in the control of cognitive functions.
Meeting abstract presented at VSS 2012