ABSTRACT
This chapter examines the relationship of unlearned (unconditioned) and learned (conditioned) cardiovascular responses to one another. These relationships between unconditioned responses (UR) and conditioned responses (CR) have important implications for our understanding of both cardiovascular regulation and behavior. Major physiological interventions have traditionally been used to study the mechanisms involved in cardiovascular regulation. These interventions have included peripheral electric shock, electrical stimulation of the brain, hypoxia, exsanguination, or transection of neural structures. The cardiovascular URs to peripheral electric shock in the loosely restrained rabbit include a change in heart rate (HR) and an increase in blood pressure (BP); whereas, the CRs usually include a change in HR, but no change in BP. When stimulation of unconditioned stimulus placements in the diencephalon elicited diffuse somatic movements, accelerative HR CRs and URs were concomitantly elicited. E. N. Sokolov has related the elicitation of autonomic CRs to neural mechanisms that facilitate or inhibit the reception of sensory input.
