Changes in pattern reversal evoked potentials during menstrual cycle

Hormonal changes that occur during the menstrual cycle of women influence t he visual function of females. Estrogen is reported to cause a decrease in the visual transmission time by increasing the sensitivity of receptors in the optic pathways to dopamine. The aim of this study was to search if patt ern reversal evoked potentials (PRVEPs) changed during the different phases of the menstrual cycle. PRVEPs of both eyes of 30 healthy women were recor ded in 4 different phases of the menstrual cycle, namely, menstrual, follic ular, ovulatory and luteal. The highest mean PRVEP latency and the lowest m ean P-100 amplitude were recorded during the menstrual phase. The mean PRVE P latency recorded during the ovulatory phase (when estrogen level rises to 3-5 times that of other phases' without an increase in progesterone levels ) was statistically significantly shorter than that of other phases' (p < 0 .05). Although not statistically significant, the mean P-100 amplitude reco rded during the ovulatory phase was higher than the ether phases. Looking a t these results, sex steroids seemed to affect the generation of PRVEPs. Th e significant decrease in PRVEP latencies when estrogen levels peaked was t hought to be due to facilitating effect of estrogen on the neural transmiss ion of the visual pathways.