Sex differences in mental rotation: Top–down versus bottom–up processing

Functional MRI during performance of a validated mental rotation task was used to assess a neurobiological basis for sex differences in visuospatial processing. Between-sex group analysis demonstrated greater activity in women than in men in dorsalmedial prefrontal and other high-order heteromodal association cortices, suggesting women performed mental rotation in an effortful, “top–down” fashion. In contrast, men activated primary sensory cortices as well as regions involved in implicit learning (basal ganglia) and mental imagery (precuneus), consistent with a more automatic, “bottom–up” strategy. Functional connectivity analysis in association with a measure of behavioral performance showed that, in men (but not women), accurate performance was associated with deactivation of parieto-insular vestibular cortex (PIVC) as part of a visual–vestibular network. Automatic evocation by men to a greater extent than women of this network during mental rotation may represent an effective, unconscious, bottom–up neural strategy which could reasonably account for men's traditional visuospatial performance advantage.