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 o f the anterior cingulate, posterior cingulate, and medial frontal cort ices on tests of visual discrimination learning, using a new ''touchsc reen'' testing method for rats. Anterior cingulate cortex lesions impa ired acquisition of an 8-pair concurrent discrimination task, whereas posterior cingulate cortex lesions facilitated learning but selectivel y impaired the late stages of acquisition of a visuospatial conditiona l discrimination. Medial frontal cortex lesions selectively impaired r eversal learning when stimuli were difficult to discriminate; lesions of anterior and posterior cingulate cortex had no effect. These result s suggest roles for the anterior cingulate, posterior cingulate, and m edial frontal colter in stimulus-reward learning, stimulus-response le arning or response generation, and attention during learning, respecti vely.