Horizontal Eye Movements from Abducens Nerve Stimulation in the Cat

Pulse trains with sinusoidally modulated pulse frequencies (50 to 150 pps) were used to stimulate the abducens nerve of the anesthetized cat. Eye movements, the measured output of the system, were observed to follow the sinusoidal modulating waveform over the modulation frequency range of 0.5 to 25 Hz. The gain and phase characteristics of such eye movements indicated the presence of a first-order system at the end of the oculomotor pathway. A delay between stimulation and eye movement of approximately 12 ms was indicated by the frequency response as well as by the step response of the system.