Visual Potentials Evoked by Pattern Stimulation with Different Spatial Frequencies in Retrobulbar Neuritis

Abstract

Numerous studies on psychophysical reaction times in man in response to pattern stimulation demonstrate a progressive increase in the latency of the response when the spatial frequency of the stimulus is increased. A similar behaviour has been recently observed with the use of evoked potentials. In this particular study the Authors demonstrate that the increase in the latency manifested by increasing the spatial frequency may be observed in the transient responses but not in those steady-state responses of relatively high temporal frequencies. This leads to the hypothesis of the progressive selection of smaller receptive fields mainly within the X-system. Keeping in mind that at the level of the retinal ganglion cells there is a progressive increase in the dimensions of the receptive fields, the Authors demonstrate that retrobulbar neuritis (either axial or peripheral) may be detected by changing the spatial frequency of the stimulus.