Sex-related asymmetries in the morphology of the left and right hippocampi? A follow-up study on epileptic patients.

Cell densities were determined in left and right surgically removed hippocampal tissue of epileptic patients. Pyramidal cells were studied in CA1, CA4, and the dentate gyrus. Lower densities of nucleolated cells were found for males in the right CA1 and CA4 than on the left while there was no significant left-right difference in females. Moreover, we found a probable sex difference in intercorrelations of nucleolated cells among the three subfields. In males, they were positive and significant on the left while they were low on the right. In females, positive significant intercorrelations were obtained between some subfields and not between other subfields, on either side. The present findings suggest greater hippocampal lateralization in males than in females with higher hippocampal neuronal connectivity on the left in males than on the right.