A RE-EXAMINATION OF EFFECTS OF FRONTAL LESIONS ON OBJECT ALTERNATION

Monkeys with lateral prefrontal lesions which spared the ventrolateral cortex relearned object alternation to a level of 80 per cent correct, although others with the same lesion failed to relearn spatial alternation. Neither form of alternation was relearned by monkeys with orbital removals that included the ventrolateral cortex. The results suggest that the classical delayed alternation deficit produced by an extensive prefrontal removal is compounded of two separate defects: one attributable to dorsolateral damage, and related to the spatial factor in the test; the other due to ventral damage and related to the reversal factor. © 1969.