POSSIBLE CONFOUNDING EFFECTS OF STROBE CLICKS ON FLASH EVOKED-POTENTIALS IN RATS

Flash evoked potentials (FEPs) undergo within- and between-session cha nges and are modified by auditory white noise (26). We examined whethe r an auditory potential produced by the ''click'' associated with the strobe discharge could be recorded, and if alterations in an auditory response could explain the within- and between-session changes in FEPs . We also examined differences between a frontal cortex or a nasal ref erence electrode location on FEPs and auditory potentials. An auditory potential associated with the strobe discharge could be clearly recor ded. This response was eliminated by the presence of 80 dB SPL masking white noise. However, the within- and between-session changes in FEPs could not be explained by modifications of the auditory potential. An imals whose ear drums were ruptured did not exhibit an auditory respon se, and their FEPs were similar to those of controls tested in the pre sence of masking white noise; A nasal reference electrode decreased th e impact of auditory potentials on FEPs, but may allow visual potentia ls (electroretinogram and optic tract activity) to influence FEPs. The data show that auditory potentials associated with the strobe dischar ge can be recorded from the visual cortex of rats, and that these audi tory responses represent a possible confounding factor in the interpre tation of toxicological studies employing FEPs.