The effects of frontal lobe damage upon habit reversal in the white rat.

Abstract

Thirty rats with frontal lesions were not significantly inferior to 30 controls in ability to learn a simple maze problem, although when the task was reversed and they were forced to change their directional choice for reward, the differences between the 2 groups were statistically significant. When complexity of the maze task was increased, operated Ss showed increased perseverative interference and a disproportionate difficulty, compared with controls. Performance on the habit of brightness discrimination was not significantly impaired in Ss with frontal lesion. When the task was reversed and the animal had to learn to choose the previously unrewarded stimulus, the difference between operated and control Ss were still not significant. A 2d reversal decreased, rather than increased, the differences between the 2 groups. Operated rats, as well as controls, show evidence of "learning to learn" brightness discrimination problems. The ability to learn the reversal of any given task does not appear to be necessarily associated with the integrity of the frontal cortex. Deficit on the part of operated Ss in learning reversal problems depends upon the type of task which is presented. It was suggested that spatial factors may be especially affected by frontal lesion, since the maze reversal habit, dependent upon motor cues and spatial orientation, indicated deficit on the part of operated Ss.