Demystifying the Visual Word Form Area: Visual and Nonvisual Response Properties of Ventral Temporal Cortex with precision fMRI

Abstract

After more than three decades of investigation, the nature and even the existence of the visual word form area (VWFA), a region in left ventrotemporal cortex (VTC), is still under debate. Here we provide novel insight on this debate by using precision fMRI to compare the VWFA to adjacent VTC regions, amodal language, and multiple-demand networks. We find that the VWFA is unique in its word-selectivity within VTC. The VWFA also uniquely shows auditory language-selectivity, but this language responsiveness is dwarfed by i) its visual-selectivity even to non-preferred stimuli and ii) language-selectivity of the language network. We additionally identify a region at the tip of the VTC which prefers auditory language to visual stimuli. Finally, almost all VTC fROIs are modulated by attention, not just the VWFA. We propose that the VWFA primarily operates as a visual look-up dictionary of orthographic information, presumably facilitated through connections with canonical language cortex.

Developing cortex is functionally pluripotent: Evidence from blindness

“…Stronger responses to faces are observed in right lateral vOTC and responses to words and letters on the left ( Cohen et al, 2000 , Dehaene and Cohen, 2011 , Gerrits et al, 2019 , Grill-Spector et al, 2004 , Kanwisher et al, 1997 , Pinel et al, 2015 ). Within hemisphere, responses to faces and letters are close but still separable in individual sighted subjects ( Dehaene-Lambertz et al, 2018 , Hasson et al, 2002 , Li et al, 2023 , Saygin et al, 2016 ).…”

Expertise in reading visual Braille co-opts the reading network

“…Several studies support the crucial role of shape in the word form system: the importance of line junctions for fluent reading (Bola et al, 2017), the partial overlap between VWFA and the areas of the ventral visual cortex that respond selectively to line junctions (Szwed et al, 2011), an equal response to line drawings of objects and false fonts (Ben-Shachar et al, 2007), and comparable levels of activation for both known letters and foreign characters (Vogel et al, 2012; Xue & Poldrack, 2007). All these results led to the suggestion that instead of responding specifically to visual words, VWFA, along with other regions located in the fusiform gyrus, might be involved in complex shape processing more generally (Li et al, 2024; Roberts et al, 2013). An alternative account of VWFA downplays the role of visual features and emphasizes the integration of this visual region with downstream language regions involved in phonological and semantic processing (Price & Devlin, 2003, 2004, 2011).…”