Sw. Porges et al., INFANT REGULATION OF THE VAGAL BRAKE PREDICTS CHILD-BEHAVIOR PROBLEMS- A PSYCHOBIOLOGICAL MODEL OF SOCIAL-BEHAVIOR, Developmental psychobiology, 29(8), 1996, pp. 697-712
Cardiac vagal tone is a construct that describes the functional relati
onship between the brainstem and the heart. Cardiac vagal tone is meas
ured by quantifying the amplitude of respiratory sinus arrhythmia, a c
omponent of heart rate variability reflecting the functional output of
vagal pathways on the heart. Although there is an extensive literatur
e evaluating baseline vagal tone and its relation to behavior, the rel
ation between individual differences in the ability to regulate cardia
c vagal tone and behavior has been theoretically vague. This article i
ntroduces a theoretical model to explain the relation between vagal to
ne during steady states and vagal reactivity (i.e., the vagal brake) i
n response to environmental challenges. Based upon the proposed model,
it was hypothesized that infants who had difficulties in regulating t
he vagal brake (i.e., decreasing cardiac vagal tone) during social/att
ention tasks would have difficulties developing appropriate social int
eractions requiring reciprocal engagement and disengagement strategies
. Data from 24 infants are presented. The findings support the model a
nd demonstrate that infants with difficulties in decreasing vagal tone
during a social/attention task at 9 months of age had significantly m
ore behavioral problems at 3 years of age. (C) 1996 John Wiley & Sons,
Inc.