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Inhibition of the expression of conditioned cardiac responses in the developing rat
Author(s) -
Hunt Pamela S.,
Hess Maureen F.,
Campbell Byron A.
Publication year - 1998
Publication title -
developmental psychobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 93
eISSN - 1098-2302
pISSN - 0012-1630
DOI - 10.1002/(sici)1098-2302(199811)33:3<221::aid-dev3>3.0.co;2-t
Subject(s) - psychology , unconditioned stimulus , heart rate , stimulus (psychology) , arousal , classical conditioning , developmental psychology , autonomic nervous system , neuroscience , endocrinology , medicine , conditioning , cognitive psychology , blood pressure , statistics , mathematics
It is generally recognized that during development the capacity to express learning in terms of changes in somatomotor activity is evident earlier than the capacity for learned changes in autonomic responding (e.g., heart rate). In this series of experiments, findings indicate that changes in heart rate to a visual conditioned stimulus (CS) paired with a footshock unconditioned stimulus (US) can be observed as early in development in the rat as freezing responses. However, cardiac responses are inhibited from being expressed by preweanlings (but not adults) during CS–US pairings, the time when heart rate responses are often measured. This inhibition appears to arise from US exposure, and dissipates completely within 2 hr of training. These findings are discussed with respect to developmental changes in US‐evoked autonomic arousal and response system dissociations. © 1998 John Wiley & Sons, Inc. Dev Psychobiol 33: 221–233, 1998