Testing hyperalgesia and hypoalgesia in human pain reactivity using shock and radiant heat

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Date

1998

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Journal ISSN

Volume Title

Publisher

Texas A&M University

Abstract

Recent animal studies pose a serious challenge for raphics. current models of pain modulation. These studies have shown that exposure to the same aversive stimulus has opposite effects on different measures of pain reactivity, reducing reactivity (hypoalgesia) on spinally mediated tests while increasing reactivity (hyperalgesia) on supraspinally mediated tests. The present experiments investigated whether humans exhibit similar divergent effects using parallel methodology. Experiment 1 examined the elects of an unpredictable shock and the threat of an unpredictable shock on pain thresholds using a radiant heat test (putative spinal mediation). Experiment 2 examined the effects of the same unpredictable shock and its threat on pain thresholds measured using a gradually incremented shock (putative supraspinal mediation). Experiment 3 used a procedure similar to Experiment 1, with the exception that unpredictable noise bursts were used as the stress-inducing stimulus. Experiment 1 revealed that shock resulted in hypoalgesia, while threat of shock resulted in hyperkinesia. Experiment 2 found that men became hypoalgesic to unpredictable shocks, but women were hyperalgesic. Experiment 3 indicated that men were hyperalgesic following noises. The effects of genders. These results suggest that the divergent elects observed in pain reactivity reflect different defensive (active vs. passive) reactions which result from divergent emotions (fear and anxiety), rather than a supraspinal vs spinal mediation difference. Results are interpreted using Walters' (1994) general adaptive model of injury related behavior.

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Includes bibliographical references (leaves 90-101).

Keywords

psychology., Major psychology.

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