Information and States of Motor Readiness: Their Effects on the Covariation of Heart Rate and Energy Expenditure


  • The research was supported by a studentship to Sherwood from the SERC, a studentship to Moncur from the MRC, and NIMH grant No. 26473 to Brener.

Address requests for reprints to: A. Sherwood, Department of Psychiatry, Medical Research Building A (218H), University of North Carolina, Chapel Hill, North Carolina, 27514.


Two studies are reported in which heart rate and oxygen consumption were monitored in rats during behavioral adaptation to avoidance conditioning tasks. In the first study, the provision of information regarding potential shock delivery for one group of animals led to them exhibiting a tendency toward increased behavioral efficiency compared with a low information group. The metabolic appropriateness of heart rate was assessed on the basis of a linear regression equation fitted to habituation data. During conditioning, both groups displayed heart rates that exceeded the predictions of this equation and, contrary to expectations, the group provided with additional information tended to display the more elevated heart rates. However, an interpretation of these effects was confounded by group differences in ambulation rates. Experiment 2 set out to test a specific hypothesis suggested by the results of the first experiment: that levels of metabolically elevated heart rates are directly related to motor preparatory states. Data in support of this hypothesis are presented, followed by a general discussion of the relationship between behavioral states and cardiovascular function.