Formation of a Conditioned Emotional Response (CER) Following Lesions of the Amygdaloid Complex in Rats

Abstract

Formation of a conditioned emotional response (CER), using suppression of food-reinforced bar-pressing as an index, was studied in a group of rats with amygdaloid lesions ( N = 5) and in a sham-operate control group ( N = 5). In contrast to control animals, which typically suppressed in two to three sessions, none of the amygdaloid operates met criterion within the set limit of 15 sessions or showed signs of suppression. Increasing the intensity and duration of shock also proved ineffective in these animals. Only by punishing each bar-press during the CS period could their responding be suppressed. Further tests on generalization of conditioned suppression, performed on two of the control animals, revealed relatively flat generalization gradients, consistent with other findings. Results were discussed in terms of amygdaloid effects on non-reinforced behavior in discrimination situations. “Inhibition” of responding associated with nonreinforcement appears to involve some of the same processes that operate in shock-motivated behavior.

Amygdaloid lesions and behavioral inhibition in the rat.

“…acquisition of a. conditioned emotiona1 response (CER) (Ke1licutt & Schwartzbaum, 1963). None of the 1esioned anima1s in this study showed any clear-cut evidence of suppression of a bar-pressing response for food reinforcement.…”

Neural and cellular mechanisms of fear and extinction memory formation

“…Similarly, the amygdala has been implicated in mediating conditioned emotional responses, including conditioned suppression. For instance, Kellicutt and Schwartzbaum (1963) trained rats with amygdala lesions to bar-press for food and then fear conditioned them. They found that rats with amygdala lesions took longer to suppress bar-pressing in response to the CS (Kellicutt and Schwartzbaum, 1963).…”

“…For instance, Kellicutt and Schwartzbaum (1963) trained rats with amygdala lesions to bar-press for food and then fear conditioned them. They found that rats with amygdala lesions took longer to suppress bar-pressing in response to the CS (Kellicutt and Schwartzbaum, 1963). Several years later, Goldstein (1965) reported that amygdala lesions resulted in deficits in the acquisition and retention of fear responses, as measured by the latency to jump out of a compartment in which a tone and shock were paired.…”

Pavlovian fear conditioning as a behavioral assay for hippocampus and amygdala function: cautions and caveats

“…In the 1960s, it was shown that damage to the amygdala impairs conditioned suppression [(i.e. using the Estes–Skinner procedure) Kellicutt & Schwartzbaum (1963)] and by the early 1970s Robert and Caroline Blanchard had demonstrated an important role for both the amygdala and hippocampus in conditioned freezing behavior (Blanchard & Blanchard, 1972; Blanchard et al. , 1977).…”