EFFECTS OF PERINATAL TESTOSTERONE ON HANDEDNESS OF GERBILS - SUPPORT FOR PART OF THE GESCHWIND-GALABURDA HYPOTHESIS

When assuming their species-typical tripodal stance, male Mongolian ge rbils (Meriones unguiculatus) use their right forepaw for support more frequently than do females. This experiment determined whether, as N. Geschwind and A. M. Galaburda (1987) have proposed, the direction of such sexually dimorphic lateral asymmetry of forelimb use is affected by perinatal exposure to testosterone (TP). It was found that male ger bils injected with TP when 4 days old were significantly less likely t o rest on their right forepaw when in a tripodal stance than were thei r oil-injected siblings. Female gerbils injected with TP when 6 days o ld were more likely than oil-injected controls to use their right fore paws for support. The findings demonstrate effects of perinatal exposu re to TP on handedness in gerbils and suggest that the relationship be tween TP exposure and asymmetrical forelimb use is not always as direc t as Geschwind and Galaburda's model suggests.