The behavioral and neurochemical changes in the chronic phase of permanent occlusion of the right middle cerebral artery (MCA) in rats were investigated. Nineteen MCA-occluded rats failed to solve the 8-arm radial maze task (cognitively impaired rats), while 11 MCA-occluded rats could complete it (cognitively unimpaired rats). When a delay of 60 min was imposed in the task, however, 5 cognitively unimpaired rats failed to complete the task. The rats that underwent behavioral testing were studied for any changes in ACh levels in various brain regions using HPLC with electrochemical detection. The ACh levels in the infarcted areas decreased considerably in all MCA-occluded rats, but no region of the infarcted areas correlated with the spatial cognitive deficit. The ACh levels tended to decrease in the frontal cortex of the cognitively impaired rats and greatly increased in both the ipsilateral and contralateral parietal cortex of the cognitively unimpaired rats. A significant correlation was observed between the ACh levels and spatial cognitive deficit in the contralateral frontal cortex, and ipsilateral and contralateral parietal cortex. These results suggest that the cholinergic function of the frontal and parietal cortices might play a role in acquiring spatial cognition in MCA-occluded rats.