[Characteristics of cortical responses to electrostimulation of the internal geniculate body during formation of a defensive conditioned reflex].

During elaboration of a classical defensive conditioned reflex the dogs exhibited a dependence of the changes in amplitude and configuration of evoked potentials (EP) to electrical stimulation of the medial geniculate body (MGB), a conditioned stimulus, on the nature of effector manifestation of the conditioned reflex: the late components were the most depressed at multiple phasic reactions and not infrequently increased and became complicated at single and short motor reactions as well as at their incidental absence. The primary oscillations, while mostly remaining unchanged, were depressed in the case of conditioned reactions attended with a general motor restlessness. A difference has been revealed during conditioning in the EP changes to electrical stimulation of MGB and to an adequate peripheral stimulation. It has been assumed that EP changes during conditioned activity are determined by the relationship between the levels of tonic and phasic cortical activation.