Sex differences in cortical plasticity and behavior following anterior cortical kindling in rats

This experiment examined the effect of electrical kindling on the morphology of frontal (Fr1) neocortical layer III pyramidal cell dendrites in both male and female rats. Repeated elicitation of afterdischarge resulted in an increase in the severity of the behavioural seizures and an increase in afterdischarge duration, frequency and amplitude in all rats. The late component of the transcallosal evoked responses also increased following both 7 and 25 kindling sessions in male rats and following 25 kindling sessions in female rats. Analysis of the Golgi-Cox impregnated pyramidal cell dendrites indicated a significant decrease in the amount of apical and basilar dendritic spine density, length and branching in female rats following 7 days, but not 25 days, of kindling. Male rats had significantly lower apical and basilar dendritic spine density and branching measures following 25 days, but not 7 days, of kindling, as well as significantly lower apical and basilar dendritic length following 7 days of kindling. The differential gender effect suggests that males and females recruit similar plastic mechanisms although at different times in response to electrical kindling.