RESUMO
Diamond and collaborators have reported sexual dimorphic right greater than left thickness asymmetries in the cerebral cortices of male Long-Evans rats. In the present work we report that normal Sprague-Dawley males show a similar cortical asymmetry. On the other hand, Sprague-Dawley males whose mothers were subjected to treatments of prenatal stress three times daily during the third trimester of gestation showed a nonsignificant left greater than right pattern in the same cortical areas--a pattern characteristic of the female cortex. These results are consistent with other findings from our laboratory wherein we have recently shown that prenatal stress during the third trimester of gestation demasculinizes sexually dimorphic regions of the preoptic hypothalamus in male rats. It is concluded that stress mediated changes in the prenatal environment can have a profound effect on the developmental processes which shape the morphology of sexually dimorphic regions of the brain in male offspring. Normal male anatomy is biased in the direction of a feminine structure. Such an anatomical picture is consistent with demasculinized and feminized behavior patterns exhibited by male offspring of prenatally stressed dams.