A METABOLIC MAPPING STUDY OF ORIENTATION DISCRIMINATION AND DETECTIONTASKS IN THE CAT

Increasing evidence suggests that a large number of distinct cortical areas and associated subcortical structures participate in the process ing of visual information and that different aspects of visual scenes are evaluated in different areas. This necessitates identification of cortical and subcortical regions cooperating in particular visual task s. Using the 2-deoxyglucose technique, we monitored the differential a ctivation of areas in the cat visual cortex participating in an orient ation discrimination and a detection task, Concordant with previous le sion studies, we found increased activity levels in area 17 in the dis crimination condition relative to the detection condition. In addition , the 2-deoxyglucose technique revealed discrimination-related increas ed activations in the claustrum, the putamen and in parts of the anter omedial, anterolateral and posterolateral lateral suprasylvian visual areas. Regions activated differentially with the detection task compri sed subdivisions of areas 17, 18, 19 and 21, posterior area 7 (7p), se veral areas of the posterior part of the middle and posterior suprasyl vian sulcus, the pulvinar complex and the superior colliculus. These r esults show that the 2-deoxyglucose technique is useful to investigate cognitive brain functions, and that different sets of cortical and su bcortical regions are activated during two visual tasks with similar v isual stimulation.