Activity of elbow flexor and extensor muscles during contact placing reaction in the cat.

Activity of the biceps brachii and of the lateral head of the triceps brachii was recorded in cats during contact placing reaction evoked by tactile stimulation of the dorsum of the forepaw. Chronically implanted electrodes were used for this purpose. Two patterns of responses were observed. In the first pattern the two muscles were activated alternately while in the second pattern they were coactivated during the first phase of the reaction. Activity of the biceps brachii preceded that of the triceps brachii in both patterns. The second pattern resembled the pattern of responses of elbow flexors and extensors to mechanical stimuli applied to the dorsum of the forelimb during locomotion.