Differential effects of prefrontal lesions and combined prefrontal and limbic lesions on subsequent learning performance in the cat.

15 cats were given lesions in either the prefrontal cortex alone (n?=?7) or in the prefrontal cortex, anterior thalamus, mamillary bodies, and subiculum (n?=?8) before being tested in the acquisition of visual-reversal, delayed-alternation, and 2-way active-avoidance tasks. Lesioned Ss were compared to 6 unoperated and 4 sham-operated controls. As an extension of E. Irle and H. J. Markowitsch's (see record 1984-19842-001) study, in which triple limbic lesions failed to impair learning behavior of cats, the present study examined the effects of a lesion in the 4th brain structure (in addition to the original triple lesions). Results indicate that, compared with controls, Ss with prefrontal lesions were impaired in the acquisition of the avoidance task. In contrast, Ss with combined lesions were unimpaired in the acquisition of the visual-reversal task, facilitated in the acquisition of the avoidance task, but impaired in the acquisition of the delayed-alternation task. The superior performance Ss with combined lesions is interpreted as due to a lesion-induced functional shift acting on intact brain structures which, prior to massive limbic lesions, remained inhibited. (56 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)