Magnitude Of Orienting Response Research Articles

Opioid modulation of Pavlovian learning in rabbits: Involvement of sublenticular pathways.

Intravenous naloxone enhanced, and D-Ala2-Met-enkephalinamide (DALA) impaired, Pavlovian conditioned heart rate discrimination in rabbits (Oryctolagus cuniculus) during initial training trials, compared with saline; naloxone also delayed subsequent extinction of the discrimination. These effects of the opioid treatments on discrimination were abolished by parasagittal knife-cut lesions in the sublenticular substantia innominata that did not, themselves, impair discrimination. Both naloxone and DALA decreased the magnitude and altered the topography of bradycardiac conditioned responses, and the lesions also abolished these effects of the opioid treatments, but they did not alter the effect of naloxone to decrease bradycardiac orienting response magnitude. These findings suggest that fibers in the sublenticular area mediate specifically the effects of systemic opioids on associative functions during Pavlovian cardiac conditioning and extinction.

The interstimulus interval in classical autonomic conditioning of young infants.

Conditioned auditory discrimination and extinction of the skin potential response were attempted in 4-month-old infants using interstimulus intervals of 1500, 3500, 5500, and 7500 msec. Half of the infants in each of the interstimulus interval groups were defined as high magnitude orienters and half were low magnitude orienters. Conditioning was successful with the 5500- and 7500-msec interstimulus intervals, but not with the 1500- and 3500-msec intervals. Analysis of individual subject data indicated that individual subject data indicated that individual differences in conditionability were related to interstimulus interval and orienting response magnitude. Also, those subjects discriminating at the longer intervals tended to be high magnitude orienters. In other words, longer interstimulus intervals interacted with a high magnitude or orienting to facilitate conditioning. The results were taken as evidence that individual differences in the magnitude of the orienting response reflect different individual needs in stimulus information processing time.

Orienting response and discrimination conditioning.

Abstract The effects of habituation or no habituation trials, alternating and random pattern of CS+ and CS− presentations, and constant and variable intertrial intervals were observed on both rate and amount of discrimination conditioning of both first and second interval galvanic skin responses in 96 students. Red and green lights of 0.5 sec duration served as CSs. Unconditioned stimulus was a 0.5 sec shock. CS-UCS interval was 5.0 sec. Both variation in orienting response magnitude and discrimination conditioning were demonstrated. However, experimentally induced variation in orienting response magnitude did not interact with either rate or amount of discrimination conditioning. CS habituation trials decreased magnitude of responding nondifferentially to both CS+ and CS− over early acquisition trials when compared with magnitude of responding of the group not receiving CS habituation trials. Similarly, the constant ITI group gave smaller responses to both CS+ and CS− than did the variable ITI group. No differences in magnitude of response between alternating and random stimulus presentation groups were found.