EFFECTS OF CAUDATE NUCLEI OR FRONTAL CORTICAL ABLATIONS IN KITTENS - BAR PRESSING PERFORMANCE

The bar pressing tasks which were used to test adult-operated cats were applied to juvenile and adult animals with bilateral caudate or frontal cortical lesions inflicted during the first month of life. Intact and sham-operated littermates served as controls. All three operated groups showed significantly slower rates of acquisition. Significantly fewer acaudate cats acquired the initial response, and only two each of the acaudates and afrontals reached the single alternation criterion. The acaudate cats, furthermore, showed significantly slower rates of transfer, overall responding, and alternation, but did not exhibit the postural adjustments seen in adult-operated animals and could bar press and drink simultaneously. There was a direct relationship between the magnitude of the deficit and the size of the caudate removal. The afrontals showed unsustained, erratic performances and were unmotivated and distractable. The data suggest that although there may be some savings in the more subtle nuances of behavior, the overall effects on bar pressing performance in the neonatally operated subjects can be just as great as when the lesions occurred later in life. © 1979.