Effects of prolonged stimulation at the electrode-retina interface.

Prolonged electrical stimulation can lead to temporary or permanent changes in neural response. Stimulation of neurons at levels sufficient to cause overlapping zones of excitation can induce multiple effects, leading to permanent damage to neurons or temporary depression not detectable through histopathological analysis. The present study focuses on determining the effects of prolonged, continuous electrical stimulation in the retina. One hour stimulation was performed in the rat retina and electrically evoked responses in the superior colliculus were recorded before and after the continuous stimulation. Comparison of the pre and post stimulation responses indicates a depression in the excitability of the neurons.