Auditory potentials elicited by the grass photic stimulator in the rat.

Flash visual evoked potentials were recorded from the rat to determine whether the Grass photic stimulator could generate an auditory component of the waveform. When the click associated with each lamp flash remained unmuffled, the primary response of the visual cortex (P30) was preceded by an earlier positivity with a latency between 6-8 ms. When the photic stimulator lamp was subsequently insulated in order to deaden the sound of the click, the P30 potential remained intact while the earlier response disappeared. It is concluded that the photic stimulator is capable of eliciting a distinct auditory potential of probable collicular origin.