The visual word form area (VWFA) is an experience-dependent brain region in the left ventral temporal cortex of literate adults that responds selectively to visual words. Why does it emerge in this stereotyped location? Past research has shown that the VWFA is preferentially connected to the left-lateralized frontotemporal language network. However, it remains unclear whether the presence of a typical language network and its connections with ventral temporal cortex (VTC) are critical for the VWFA's emergence, and whether alternative functional architectures may support reading ability. We explored these questions in an individual (EG) born without the left superior temporal lobe but exhibiting normal reading ability. Using fMRI, we recorded brain activation to visual words, objects, faces, and scrambled words in EG and neurotypical controls. We did not observe word selectivity either in EG's right homotope of the VWFA (rVWFA)—the most expected location given that EG's language network is right-lateralized—or in her spared left VWFA (lVWFA), in the presence of typical face selectivity in both the right and left fusiform face area (rFFA, lFFA). Interestingly, multivariate pattern analyses revealed voxels in EG's rVWFA and lVWFA that showed 1) higher within- than between- category correlations for words (e.g., Words-Words>Words-Faces), and 2) higher within-category correlations for words than other categories (e.g., Words-Words>Faces-Faces). These results suggest that a typical left-hemisphere language network may be necessary for the emergence of focal word selectivity within ventral temporal cortex, and that orthographic processing may depend on a distributed neural code, which appears capable of supporting reading ability.
A dual-route perspective on brain activation in response to visual words: Evidence for a length by lexicality interaction in the visual word form area (VWFA)
