Reduction of freezing behavior and improvement of shock avoidance by d-amphetamine.

Amphetamine-induced freezing in a food-motivated operant task

“…These results suggestthattheeffectofamphetamine on intermittently-reinforced operant behavior and on freezing are independent, and that the drug does not depress food-motivated performance by merely increasing the interference of such performance with freezing. In contrast to the findings of the present study, Krieckhaus et al (1965) did find Significant negative correlations between freezing and avoidance performance following administration of amphetamine.…”

“…It is of particular interest to note that the amount of freezing observed on the four trials of the present study following injection of 2 mg/kg of amphetamine is similar to that observed by Krieckhaus et al (1965) in the CAR task following administration of the drug in the same dose. The average freezing rating of the drug group over the four trials of the present study was 3.5 (a rating of 3 on the present scale corresponds to one of 2 on the scale presented by Krieckhaus).…”

“…These results were discussed in relationship to the amphetamine-induced reduction of freezing which has been observed in the CAR task. Krieckhaus et al (1965) have presented evidence that amphetamine reduces the CS-induced freezing in the CAR task thereby facilitating performance. However, such a reduction in freezing by amphetamine is observed in a situation where the pre-existing level of freezing in response to the CS is considerable.…”

Residual capacity for avoidance learning in decorticate rats; Enhancement of performance and demonstration of latent learning with d-amphetamine treatments

“…In the case of CAR acquisition studies, the facilitated learning seemed to be related to the locomotor stimThis research was supported, in part, by Grant MH-06211 from ulant properties of the drug. Thus, increased movement (Cardo, 1960) or decreased freezing and crouching (Krieckhaus, 1965;Krieckhaus, Miller, & Zimmerman, 1965) could account for the enhanced learning. Such an explanation, however, could not account for the recovery of black-white habits in amphetamine-treated rats with posterior decortications, for the drug facilitated relearning but not initial acquisition of the habit .…”

Role of drug effects and UCS intensity in avoidance acquisition of the Maudsley MNR and MR strains

“…The intertrial interva[ varied randomly within a range of 2040 sec (mean = 30 sec). In addition to CARs, intertrial hurdle crossings (IHCs) and ratings of freezing activity in the 2 sec preceding each CS presentation were recorded (see Krieckhaus et al, 1965, for a description of the rating scale).…”