A ventral visual stream reading center independent of visual experience

Abstract

The visual word form area (VWFA) is a ventral stream visual area that develops expertise for visual reading. It is activated across writing systems and scripts and encodes letter strings irrespective of case, font, or location in the visual field with striking anatomical reproducibility across individuals. In the blind, comparable reading expertise can be achieved using Braille. This study investigated which area plays the role of the VWFA in the blind. One would expect this area to be at either parietal or bilateral occipital cortex, reflecting the tactile nature of the task and crossmodal plasticity, respectively. However, according to the metamodal theory, which suggests that brain areas are responsive to a specific representation or computation regardless of their input sensory modality, we predicted recruitment of the left-hemispheric VWFA, identically to the sighted. Using functional magnetic resonance imaging, we show that activation during Braille reading in blind individuals peaks in the VWFA, with striking anatomical consistency within and between blind and sighted. Furthermore, the VWFA is reading selective when contrasted to high-level language and low-level sensory controls. Thus, we propose that the VWFA is a metamodal reading area that develops specialization for reading regardless of visual experience.