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According to Deikman (1966), meditation (defined as a training to sustain attention) has a deautomatizing effect. This ascertion was utilized in the present study as a departure point and explored within an information processing framework for classical conditioning. A sample of 48 college students was selected and randomly assigned to four conditions with different instructional sets involving allocation of attention during a classical conditioning background situation. The basic hypothesis of the study was that provided arousal factors were controlled, focusing of attention upon internal stimulation (i.e. breathing) could delay or attenuate the affect of conditioning, habituation and extinction as compared with instructions to externally allocate attention (on the CS and US). A secondary hypothesis predicted that for subjects under switching conditions changing from internal to external allocation and vice versa would produce a more pronounced extinction pattern as compared with subjects under non—switching conditions.

Three Pavlovian conditioning experiments with rats were performed to test predictions from models of associative learning. The procedure in all 3 experiments involved assessing conditioned responding to a Light that was compounded with either perfect or imperfect auditory signals for food. In Experiment 1 a partially reinforced Light which signaled 100% of the food pellets acquired a greater ability to elicit a conditioned response when the auditory cues with which it was paired were relatively poor predictors of the food. In Experiment 2 the Light was still a moderate positive predictor for food, but food was presented both in the presence and absence of the Light. Responding to the Light again was reliably higher when the auditory cues were poor predictors of food. Experiment 3 replicated the results from Experiment 2 and included two control conditions to assess sensitivity to the absolute validity of the Light. In both control conditions the Light was uncorrelated with the US. In one condition the number of food presentations was the same as in the experimental condition, while in the second the number of Light-food pairings was maintained. Results suggested that regardless of the absolute contingency of the Light responding was higher when the auditory cues were uncorrelated with food. These findings suggest that associative models of cue competition make accurate predictions of conditioned behavior following exposure to multiple predictors of reinforcement.

Research over the past several decades has revealed that the amygdala is involved in aversive, or fear, conditioning. However, the precise nature of this involvement remains a matter of debate. One hypothesis suggests that disrupting amygdala function eliminates the storage of memories formed during aversive conditioning, eliminating the production of internal responses that alter the expression of observable behaviors. Alternatively, lesions or inactivation of the amygdala may impair the modulation of memories in other brain regions and disrupt the ability to perform certain observable behaviors. The experiments reported in the present thesis examined these arguments by making multiple behavioral measures during exposure to unconditioned (US) or conditioned (CS) aversive cues. Amygdala activity was inferred from changes in c-Fos protein expression or activity was temporarily suppressed with muscimol injections. The relationship between the behavioral measures and the role of the amygdala in producing them was examined. Amygdala neurons expressing the c-Fos protein tracked exposure to the US and CS but did not coincide with expression of freezing. Temporary inactivation of the amygdala with muscimol injections before presentation of the US or exposure to the CS attenuated the expression of freezing and active place avoidance; two incompatible behaviors. Finally, temporary inactivation of amygdala activity blocked freezing, place avoidance, and memory modulation produced by the same posttraining exposure to an aversive CS. Since amygdala activation alone was not sufficient to produce freezing and inactivation of the amygdala eliminated freezing, place avoidance, and memory modulation, the results cannot be interpreted as reflecting a direct role for the amygdala in production of observable behaviors. The results also preclude the idea that memory modulation is the only function of the amygdala. Rather, the results of all three studies suggest that the amygdala stores an aversive representation of the US which promotes the expression of various behaviors, possibly through the production of internal responses reflecting an aversive affective state.

Thesis (Ph. D.)--University of New South Wales, 2005. / Also available online.

Thesis (Ph.D.). / Written for the Dept. of Psychology. Title from title page of PDF (viewed 2008/08/04). Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 128-140). Available also in a digital version from Dissertation Abstracts.