A comparison of the effects of bilateral and unilateral infusions of muscimol into the basal forebrain on cued detection of visual targets in rats.
This study investigated the role of the basal forebrain cholinergic system (BFCS) in rats' performance of a visuospatial attention task. Muscimol was infused bilaterally and unilaterally into the BFCS to inhibit cholinergic projections to the cortex. Muscimol slowed responding without significantly affecting side-bias. Bilateral infusions increased accuracy for all targets, whereas unilateral infusions reduced accuracy for targets contralateral to the infusion and increased accuracy for targets ipsilateral to the infusion. After a low unilateral dose of muscimol, invalid cues impaired detection of contralateral targets and spared detection of ipsilateral targets. A high unilateral dose of muscimol impaired detection of contralateral targets independently of cueing. These results suggest that interhemispheric imbalance in cortical activity by pharmacological manipulation of the BFCS can impair the detection of lateralized visual stimuli.