Two-way communication between the heart and the brain: Significance of time within the cardiac cycle.

Summarizes results of research dealing with time within the cardiac cycle as an experimental variable. In a variety of different experiments, meaningful sensorimotor events produced changes in heart rate that were systematically related to where in the cardiac cycle the events occurred. This function is proposed as a noninvasive measure in intact humans of cortically mediated effects on vagal control of the heart. Time within the cardiac cycle is also a dependent variable: Self-initiated responses are postponed to increasingly later times as momentary heart rate increases. It is hypothesized that this may result from visceral afferent feedback to the CNS via the baroreceptor nerves. Preliminary results are presented from acute cat experiments showing that changes in frequency of carotid sinus stimulation and differences in the direction of change affect the temporal pattern of discharge of the carotid sinus nerve. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)