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Biomedical subjects

H Davis

Publications and source records attributed to H Davis.

At least 253 records · Page 14Linked to original sources
PubMedDate not supplied

Summation of excitatory and inhibitory control produced by traditional tone-shock contingencies and autocontingencies.

Previous research has demonstrated that rats can be unsignaled shock to predict subsequent periods free from shock. This shock-no shock stimulus arrangement, termed an autocontingency, has appeared less likely to exert behavioral control when a traditional tone-shock contingency was simultaneously available. The present research examined the generality of CS-US contingency dominance in a conditioned suppression paradigm by using a summation test in which "probe" stimuli derived from tone-shock contingencies were superimposed upon responding maintained by an autocontingency. In experiment 1, an inhibitory CS accelerated responding only when responding was normally suppressed by the autocontingency. In experiment 2, an excitatory CS failed to yield conditioned suppression during an inhibitory (accelerative) period produced by the autocontingency. Unlike our previous findings (e.g., Davis, Memmott & Hurwitz, 1975), these results do not support a general notion of tone-shock contingency dominance over autocontingencies. Behavioral control by autocontingencies appears robust and "holds its own" in summation with both excitatory and inhibitory CSs derived from traditional contingencies.

Animals↗
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Others.

It has been possible for many sadistic leaders to achieve absolute power in their communities in this century. How have they managed to persuade citizens to help them establish a reign of terror? How we perceive others determines our reaction to them, and our perceptions can be manipulated.

Authoritarianism↗
PubMedDate not supplied

Ethnicity, family history of hypertension and patterns of hemodynamic reactivity in boys.

This study compared blood pressure, heart rate, stroke volume, vascular resistance, and cardiac output responses to a video game challenge and forehead cold stressor in 6- to 15-year-old males who varied in ethnicity and family history of essential hypertension. Controlling for age, significant baseline differences were obtained with black boys exhibiting higher systolic and diastolic pressures than their white cohorts. Positive family history children were found to have higher cardiac outputs and stroke volumes indexed by body surface area during baseline. Controlling for baseline hemodynamic responses and age, positive family history children exhibited greater increases in systemic vascular resistance and systolic and diastolic pressure and greater decreases in heart rate to the cold stressor. The positive family history children exhibited greater decreases in cardiac index during both the video game and cold stressor phases. Implications of the findings and directions for future research are discussed.

Arousal↗