Activity of the elbow flexor and extensor muscles during contact placing elicited by tactile stimulation of various aspects of the forelimb in the cat.

The activity of the biceps brachii and lateral head of the triceps brachii were compared during the contact placing reactions elicited by tactile stimuli applied to the lateral, medial or dorsal aspects of the forepaw to verify the hypothesis that common movement strategy was used in all these reactions. Similar latencies and patterns of muscle activation have been found for the medial and dorsal placing while the different timing of the muscle activation was seen in lateral placing reactions. Both muscles often coactivated during lateral or dorsal and less frequently during medial placing reactions. In dorsal placing the coactivations predominated at the beginning of the reactions while in lateral placing they appeared most frequently in later phases of the reaction. The co-contraction of the elbow flexor and extensor muscles leads to locking of the elbow joint. Thus, the coactivation of these muscles in different phases of the lateral, medial and dorsal placing reactions indicates that various movement strategies have been used as the elbow flexion movement is initiated in different phases of these reactions.