Triple dissociation of anterior cingulate, posterior cingulate, and medial frontal cortices on visual discrimination tasks using a touchscreen testing procedure for the rat

Four experiments examined effects of quinolinic acid-induced lesions of the anterior cingulate, posterior cingulate, and medial frontal cortices on tests of visual discrimination learning, using a new ''touchscreen'' testing method for rats. Anterior cingulate cortex lesions impaired acquisition of an 8-pair concurrent discrimination task, whereas posterior cingulate cortex lesions facilitated learning but selectively impaired the late stages of acquisition of a visuospatial conditional discrimination. Medial frontal cortex lesions selectively impaired reversal learning when stimuli were difficult to discriminate; lesions of anterior and posterior cingulate cortex had no effect. These results suggest roles for the anterior cingulate, posterior cingulate, and medial frontal colter in stimulus-reward learning, stimulus-response learning or response generation, and attention during learning, respectively.