Developmental constraints on the expression of behavioral and heart-rate orienting responses: I. The role of cardiosomatic coupling.
The ontogeny of behavioral and heart-rate orienting responses to a novel olfactory stimulus was examined in three experiments. The results of Experiment 1 demonstrated that behavioral responses to the olfactory stimulus were observed as early as Day 1, although heart-rate deceleration in response to the stimulus was not observed until Day 9. In Experiment 2, bradycardia was observed in 6-day-old pups if stimulus-elicited motor activity was reduced with haloperidol. Thus, the developmental asynchrony in the expression of behavioral and heart-rate orienting responses was due, at least in part, to cardiosomatic coupling in the very young animal. The results of Experiment 3 demonstrated that although cardiosomatic coupling interferes with the expression of the heart-rate orienting response very early in development, it has increasingly less impact over the course of the preweaning period.
Hayne
H
H
Department of Psychology, Princeton University, NJ 08544-1010.
Richardson
R
R
Campbell
B
B
D000375:Aging / Q000523:psychology*; D000818:Animals; D000831:Animals, Newborn; D001143:Arousal; D001288:Attention; D006339:Heart Rate; D011939:Mental Recall; D009043:Motor Activity; D009949:Orientation; D051381:Rats; D012903:Smell; D012931:Social Environment