Physiological analysis of the effect of micropolarization on trace processes.

Abstract

1. The combination of rhythmic lifting of one forelimb and simultaneous continuous pressor stimulation of the same limb in cats leads to the formation of a conditioned motor reflex to time. Trace motor responses in the assigned rhythm can be detected either during continuous pressor stimulation or during micropolarization of the sensomotor or motor cortex, the body of the caudate nucleus, corpus callosum, and mesencephalic reticular formation by currents of 0.3–1.5 μA. 2. A combination of rhythmic lifting of the forelimb with continuous micropolarization of the sensomotor cortex in the region of representation of the lifted limb by a current of 0.5–1.5 μA also leads to formation of a conditioned reflex to time. Trace motor responses are detected to continuous micropolarization of this same cortical area alone or to subthreshold pressor stimulation of the trained limb alone. 3. It is suggested that these phenomena may have a common physiological mechanism: prolonged activation (through pressor stimulation or micropolarization) of sensory and motor cortical projections of the proprioceptive stimulus facilitates the formation of a trace reflex, such as a conditioned reflex to time.