Murdoch University Research Repository

Welcome to the Murdoch University Research Repository

The Murdoch University Research Repository is an open access digital collection of research
created by Murdoch University staff, researchers and postgraduate students.

Learn more

Acoustic startle stimuli inhibit pain but do not alter nociceptive flexion reflexes to sural nerve stimulation

English, A. and Drummond, P.D.ORCID: 0000-0002-3711-8737 (2021) Acoustic startle stimuli inhibit pain but do not alter nociceptive flexion reflexes to sural nerve stimulation. Psychophysiology, 58 (4). e13757.

Link to Published Version: https://doi.org/10.1111/psyp.13757
*Subscription may be required

Abstract

Acoustic startle stimuli inhibit pain, but whether this is due to a cross‐modal inhibitory process or some other mechanism is uncertain. To investigate this, electrical stimulation of the sural nerve either preceded or followed an acoustic startle stimulus (by 200 ms) or was presented alone in 30 healthy participants. Five electrical stimuli, five acoustic startle stimuli, 10 startle + electrical stimuli, and 10 electrical + startle stimuli were presented in mixed order at intervals of 30–60 s. Effects of the startle stimulus on pain ratings, pupillary dilatation and nociceptive flexion reflexes to the electric shock were assessed. The acoustic startle stimulus inhibited electrically evoked pain to the ensuing electric shock (p < .001), and the electrical stimulus inhibited the perceived loudness of a subsequent acoustic startle stimulus (p < .05). However, the startle stimulus did not affect electrically evoked pain when presented 200 ms after the electric shock, and electrically evoked pain did not influence the perceived loudness of a prior startle stimulus. Furthermore, stimulus order did not influence the pupillary responses or nociceptive flexion reflexes. These findings suggest that acoustic startle stimuli transiently inhibit nociceptive processing and, conversely, that electrical stimuli inhibit subsequent auditory processing. These inhibitory effects do not seem to involve spinal gating as nociceptive flexion reflexes to the electric shock were unaffected by stimulus order. Thus, cross‐modal interactions at convergence points in the brainstem or higher centers may inhibit responses to the second stimulus in a two‐stimulus train.

Item Type: Journal Article
Murdoch Affiliation(s): Psychology, Counselling, Exercise Science and Chiropractic
Publisher: Wiley
Copyright: © 2021 Society for Psychophysiological Research
URI: http://researchrepository.murdoch.edu.au/id/eprint/59397
Item Control Page Item Control Page