Sex Differences in Lateralization Revealed in the Posterior Language Areas

Abstract

It has been hypothesized that language functions are more strongly lateralized to the left hemisphere in males than in females. Previous anatomical data and patient studies have suggested that the posterior language areas should exhibit sex differences. However, neuroimaging studies to date have only provided support for differences in the anterior language areas. To look for differences in the posterior language areas, functional magnetic resonance imaging scans were obtained while male and female subjects listened attentively to a story read aloud and to the same story replayed in reverse. Comparing activation in the superior and the middle temporal gyri during a story to activation during reverse replay of the story showed lateralization to the left in males but not in females. There was no lateralization in either sex when comparing activation during random fragmentation of the story to reverse replay. In the angular and the supramarginal gyri, however, activation was lateralized to the left hemisphere in both sexes, unlike the sex-dependent activation of the posterior temporal lobes. We infer that females use the posterior temporal lobes more bilaterally during linguistic processing of global structures in a narrative than males do.

Sex-dependent neurofunctional predictors of long-term maintenance of visual word learning

“…As we have argued [2], left and bilateral fusiform may be respectively optimal for males' and females' learning of a new script because of native language tuning. That is, males show left lateralization when processing native language, whereas females show bilateral activation [11,15,20]. It should be noted that our study found similar fusiform activation pattern and similar behavioral performance for males and females at the group level in learning a new language.…”

“…Some researchers found that males show more left-lateralized activation and females show more bilateral activation during language processing [11,15,20]. Using Xue et al's [29] paradigm and a larger sample, Chen et al further showed that the neurofunctional predictors of visual word learning effi-ciency varied between the two sexes [2].…”

“…The functional ROI of fusiform was defined based on the group activation (including both males and females, p < .001, uncorrected) within the anatomical boundary of fusiform according to the automated anatomical labelling map (AAL) [27]. Based on theoretical considerations of sexdependent cerebral asymmetry in language processing and previous research [11,15,20], Chen et al developed two neurofunctional predictors [2]. One was asymmetric index (AI) in this area.…”

Parasagittal Asymmetries of the Corpus Callosum

“…structural asymmetry) of the cortex. More precisely, hemispheric differences of callosal thickness and area measurements were more pronounced and significant in males than in females, which might be related to the decreased anatomical asymmetry and functional lateralization often observed in females (Lake and Bryden, 1976;Kulynych et al, 1994;Kansaku et al, 2000;Good et al, 2001;Hiscock et al, 2001;Medland et al, 2002). The present study revealed distinctive and extensive asymmetries in the anterior body and additionally in a small and less significant region in the anterior third of the CC of males.…”

Dichotic Listening Tests of Functional Brain Asymmetry Predict Response to Fluoxetine in Depressed Women and Men

“…The tendency for women to perform better on verbal tasks and men to perform better on spatial tasks appears to be related to differences in hemispheric specialization (Hiscock et al, 1995). Studies have found evidence that the superiority of women for verbal processing results from their having bilateral activation of frontal and temporal lobe regions involved in language processing, whereas men are more left lateralized for verbal processing (McGlone, 1980;Bryden, 1988;Shaywitz et al, 1995;Kimura, 1999;Kansaku et al, 2000). Gur et al (2000) found that men also show more right-lateralized activation of inferior parietal and temporal lobe regions during a visuospatial task and tend to perform better when compared to women.…”