Tonic and Phasic Relationships Between Heart Rate and Somato‐motor Activity in Monkeys

Heart rate (HR) and somato‐motor activity were measured in monkeys (Macaca mulatto) during sessions when the animals were operantly conditioned to slow and to speed HR. Tonic (baseline) levels of HR were independent of somato‐motor activity. Phasic changes of HR during conditioning were variably coupled with phasic chants in activity. The discriminative cues which signaled the operant contingencies reliably elicited cardiac operants and somato‐motor responses. Monotonic trends in cardiac phasic activity generally were independent of phasic responses in somato‐motor activity. Short term phasic responses in HR often were correlated with short term phasic responses in somato‐motor responses. The findings indicate that the relationship of HR to somato‐motor activity) depends upon temporal adjustments within given conditions and stages of training, and upon particular adjustments within each animal. The main conclusion of this study is that HR and somato‐motor activity are variably coupled hut that conditioned HR responses are not necessarily caused by somato‐motor responses.