Computer simulation of the neural discharge carried by the abducens nerve during eye fixation in the cat.

The neural signal carried by the abducens nerve during eye fixations was simulated. The neural discharge was defined by the number of spikes carried by the abducens nerve within each ms. Calculations were based on real neurophysiological data. The computed neural signal showed frequency histograms and variance/mean ratios typical of a Poisson distribution. A peak was obtained in the power spectral density function of the simulated neural signal. This peak appeared in the frequency range corresponding to the firing rate of single motoneurons for each eye position. It remained as a broad spectral peak after filtering by a second-order differential equation simulating the ocular mechanics. The obtained spectra are similar to the described power spectral density function of eye position recordings. Present results add evidence of a possible neural basis for ocular tremor.