Influence of stimulation of the head of the caudate nucleus on the activity of postural muscles during realization of an instrumental defensive reflex.

A model of instrumental defensive reflexes associated with the maintenance of a specific posture was used in chronic experiments with four dogs to demonstrate the preferential inhibitory influence of preliminary low-frequency stimulation (2 impulses/sec) of the head of the caudate nucleus in the right and left hemispheres on the electromyographic and mechanographic components of the instrumental defensive reflex effecting the reflex motor program. Subjected to the greatest changes were the postural components of the electromyogram, which permits the postulate as to the importance of the caudate head in the organization of posture. It was shown that the caudate head is bilaterally involved in the prerelease processes preceeding the instrumental response.

[Effect of stimulation of the head of the caudate nucleus on differentiation of acoustic signals in a defensive situation in the dog].

In chronic experiments with a model of instrumental defensive reflexes, the influence of preliminary low-frequency stimulation of n. caudatus head on differentiation of acoustic signals was studied in six dogs. By their motor behaviour the animals were conditionally divided into two groups: excitable and quiet dogs.

[Effect of stimulation of the head of the caudate nucleus on the activity of posture muscles during development of the instrumental avoidance reflex].

In chronic experiments on dags, instrumental avoidance reflexes associated with maintenance of a certain posture, revealed prevalence of inhibitory effect of preliminary low--frequency (2/ sec) stimulation of caudate nucleus' head in the right as well as left hemisphere on electromyographic and mechanographic components of the reflex actualizing its motor program. The most dramatic changes occurred in the posture components of the EMG which suggests the importance of the caudate nucleus' head for posture organization. The caudate nucleus' head is bilaterally involved in the pretriggering processes forerunning the instrumental reflex.