Serial lesion effect in rat medial frontal cortex as a function of age.

This experiment examined the potential for behavioral recovery in juvenile, adult, and senescent rats following serial lesions of medial frontal cortex. The subjects were trained on spatial delayed alternation in a T-maze under conditions designed to enhance the probability of a serial lesion effect. All subjects were given extensive handling and adaptation to the maze, interoperative training, and long interoperative and postoperative intervals. There were several major behavioral findings: (a) the aged intact subjects were not impaired in their ability to learn spatial delayed alternation, (b) one-stage bilateral lesions of frontal cortex produced equivalent deficits on spatial delayed alternation at all ages, (c) subjects in all of the age categories demonstrated a serial lesion effect, but (d) the 150 day and 570 day serial lesions groups demonstrated significantly better performances than the 35 day serial lesions group on several measures of performance.