HEMIDECORTICATE LEARNING DEFICIT - EVIDENCE FOR A QUANTITATIVE IMPAIRMENT

The experiment is concerned with investigating the source of the instrumental learning deficit of the functionally hemidecorticated rat. This impairment could derive from either (a) a deficit in the process of information equilibration, or (b) an impairment in the processes of stimulus sampling and encoding. The avoidance learning of normal control and unilateral cortical spreading depression animals was studied over the four intertrial intervals of 15, 30, 60 and 240 sec. The results showed a severe learning deficit for the unilateral subjects at all intertrial intervals. The impairment was not due to any changes in the equilibration processes, but was indicative of a disturbance of stimulus sampling and encoding. This appeared not as a qualitative defect, but as a quantitative deviation from the normal. © 1969.