Neuronal basis of behavior in Tritonia. II. Relationship of muscular contraction to nerve impulse pattern

Recordings were made of the movements elicited in the body of Tritonia diomedia by direct intracellular stimulation of identified brain neurons, which have a motor command function. It was shown that the latency of a movement response decreases as the frequency of stimulation is increased in the range 1 Hz to 20 Hz. Over the same range, the speed of the response increases. The extent, and also the speed, of a movement are proportional to the total number of stimuli, but response speeds and magnitudes vary greatly at different times. The minimum latency, after deduction of conduction time, is 160 ms at 11 °C. It is concluded that the identified brain cells, which cause discrete movements, do so indirectly, by activating a peripheral nerve net which in turn excites the muscle fibers. The nerve net is the site of independent excitatory, inhibitory, and local reflex action.