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Developmental and pharmacological analysis of the cardiac response to an acoustic startle stimulus
Author(s) -
Richardson Rick,
Wang Peiyin,
Campbell Byron A.
Publication year - 1996
Publication title -
psychophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.661
H-Index - 156
eISSN - 1469-8986
pISSN - 0048-5772
DOI - 10.1111/j.1469-8986.1996.tb02106.x
Subject(s) - stimulus (psychology) , psychology , startle response , moro reflex , heart rate , bradycardia , autonomic nervous system , fear potentiated startle , audiology , coactivation , reflex , developmental psychology , neuroscience , medicine , electromyography , fear conditioning , cognitive psychology , blood pressure , amygdala
Abstract The purpose of this research was to study the cardiac response of preweanling and adult rats to 10 presentations of an acoustic startle stimulus (0 ms rise time, 100 ms, 130 dB, white noise stimulus). The first presentation of the startle stimulus produced a decrease in heart rate (HR) at both ages. With continued stimulus presentations, the response shifted to tachycardia in the adults but remained bradycardia in the preweanlings. Pharmacological analysis revealed that the startle stimulus activated only the parasympathetic system in the preweanling rats on all 10 trials. In contrast, the startle stimulus produced coactivation of the parasympathetic and sympathetic systems in the adults on the first trial, with the parasympathetic system predominating, and solely sympathetic activation on later trials. These results are discussed in terms of current psychophysiological models of (a) the cardiac response to startle stimuli and (b) autonomic space.