Abstract
BACKGROUND: Visual words and faces activate similar networks and particularly regions in the fusiform gyri, but with complementary hemispheric asymmetries, faces being lateralized more to the right hemisphere, and words to the left hemisphere. It has been suggested that this reflects developmental competition for neural resources between visual word and face processing, possibly with word lateralization occurring first and driving face lateralization later (Dundas et al, J Exp Psychol Gen 2012, oi: 10.1037/a0029503). OBJECTIVE: Our goal was to investigate whether such competition was reflected in an inverse correlation between the degree of lateralization of visual word and face activation in the fusiform gyri in a given subject. METHODS: 26 literate right-handed healthy adults underwent a functional MRI program with a dynamic face localizer and a word localizer. First, cluster size and peak responses of the visual word form areas and fusiform face areas in the left and right hemispheres were examined, and a lateralization index derived. These indices were then correlated across subjects, between visual words and faces. Second, the analysis was repeated for all face- and word-selective voxels in the inferior occipitotemporal cortex. RESULTS: There were no significant negative correlations between the lateralization indices of visual words and faces, in either the individual regions of interest or the inferior occipitotemporal cortex as a whole. CONCLUSION: If developmental competition between visual words and faces exists, this is not reflected in a complementary relationship between visual word and face activation in right-handed adults. This suggests the existence of other, perhaps more dominant factors that generate lateralization of function.
Meeting abstract presented at VSS 2013