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Biomedical subjects

R M Tarpy

Publications and source records attributed to R M Tarpy.

8 recordsLinked to original sources
PubMed1994

Ivanov-Smolensky conditioning: relationship between CR and UR form and intensity.

The Ivanov-Smolensky conditioning procedure involves a CS followed by a command (US). There are two URs--an instructed UR and a reflexive UR such as an autonomic reaction. Anticipatory responses during the CS, of either the instructed or reflexive UR, provide a measure of conditioning. We examined whether the reflexive CR and UR are similar in form, and whether larger reflexive CRs and URs are associated with larger instructed URs. Subjects were asked to exhale "quickly and powerfully" (exhalation was thus the instructed UR) either following (Forward) or prior to (Backward) a light CS; a change in heart rate to the CS (reflexive CR) alone was the index of conditioning. The heart rate CR and UR were both deceleratory in nature, although the onset of the CR was faster than the UR. In addition, Backward-conditioned subjects demonstrated some degree of inhibitory control by the CS. Finally, the CR intensity was inversely related to exhalation magnitude.

Adult↗
PubMed1975

Hypothalamic self-stimulation in rats following immunosympathectomy or central nerve growth factor antiserum injection.

In Experiment 1, immunosympathectomized rats self-stimulated at a much lower rate on high variable ratio schedules of reinforcement than injected controls. No differences were found for responding on continuous reinforcement or low variable ratio reinforcement schedules. In Experiment 2, a similar reduction in varialbe ratio response rate was found for subjects centrally injected with nerve growth factor-antiserum relative to controls. The results suggest a reduction in central catecholamine levels as a result of antiserum treatment.

Animals↗
PubMed1974

Stimulus control of heart rate by auditory frequency and auditory pattern in pigeons.

A new method was used to investigate auditory discrimination in pigeons. Basically, the method involves the repeated presentation of one stimulus preceding the single presentation of a different stimulus that is followed by shock. Stimulus control is assessed by the increase in heart rate that accompanies the presentation of the second stimulus. In Experiment 1, the efficiency of the method was explored by determining the frequency difference thresholds of pigeons at 500, 1000, 2000, and 4000 Hz. Weber fractions comparable to those reported in an earlier study using the conditioned suppression method were obtained. Experiment 2 demonstrated that, contrary to results of earlier studies, auditory temporal patterns can exercise differential stimulus control in pigeons. One stimulus consisted of the presentation (once per second) of a 1000-Hz pure tone of 150 msec duration followed by a 2000-Hz pure tone of equal duration; the other was the same except for the reversed order of the frequency components. Results indicated that the frequency pattern and not the loudness pattern of the stimuli was the cue controlling heart-rate changes.

Acoustic Stimulation↗