Role of freezing and fear in avoidance decrements following mammillothalamic tractotomy in cat: I. Two-way avoidance behavior

Role of freezing and fear in avoidance decrements following mammillothalamic tractotomy in cat: II. Appetitively motivated behavior

“…Thus, a change in behavior that presumably would have been facilitated by increased freezing was not enhanced by MTT lesions. Third, Krieckhaus & Chi (1966) have shown that if a stimulus capable of prodUCing intense fear and freezing is introduced along with the regular CS, the animal's avoidance performance is actually enhanced. Fourth, in this same study, when cats were tested in a two-way avoidance apparatus large enough for the cat to move around in if it did not cross the hurdle, CAR decrements after MTT lesions were often accompanied by behavior quite incompatible with freezing.…”

“…It had appeared earlier (Thomas et aI, 1963) that this avoidance deficit might be attributable to increased freezing behavior. Although this explanation has received little support in subsequent work (Krieckhaus, 1964a;Krieckhaus & Chi, 1966), these studies can not be considered conclusive since in each case evaluation of changes in freezing was confounded with concomitant changes in avoidance behavior.…”

Acquisition of the two-way avoidance response in chicken compared to rat and cat

“…This difference is particularly striking as one ascends the phylogenetic scale within mammalia. It is well established that sectioning of the pathway from the mammillary bodies to the anterior thalamic nuclei (mammillothalamic tractotomy) produces a profound deficit in the retention of the difficult conditioned avoidance response in two species of mammalia-cat (Thomas, Fry, Fry, Slotnick, & Krieckhaus, 1963;Krieckhaus, 1964;Krieckhaus & Chi, 1966) and rat (Krieckhaus, 1965). The above observations raise the question of whether infra-mammals might not be deficient in the acquisition of such avoidance responses since they appear to be deficient in a neural system which seems to mediate this behavior in higher organisms.…”