Schedule of Events | Symposia

Tactile word form responses in parietal cortex of proficient blind braille readers

Poster Session F - Tuesday, April 1, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Abby Clements¹ (acleme18@jh.edu), Elizabeth esaccon2@jhu.edu¹, Mengyu Tian², Marina Bedny¹; ¹Johns Hopkins University, ²Beijing Normal University

Reading recruits specialized neural populations in the ventral visual stream (vOTC), including the so-called ‘visual word form area’ (VWFA). The VWFA neighbors the fusiform face area and parahippocampal place area but is functionally distinct from these regions. We hypothesized that blind readers would recruit analogous braille-specialized neural populations in posterior parietal cortices, which participate in high-level tactile perception. Congenitally blind braille readers (N = 20) participated in two experiments. In Experiment 1, participants read braille words and consonant strings, touched shapes made from braille dots, and listened to spoken words and backwards speech. In Experiment 2, blind participants touched small 3D models of faces and small maze-like ‘places.’ Sighted participants (N = 20) performed analogous visual experiments. A leave-one-run-out analysis in blind participants identified voxels in left parietal cortices that respond more to braille words than shapes made of braille dots (t(19) = 4.6, p < 0.001). These voxels also prefer braille words to spoken words t(19) = 4.7, p < 0.001). Additionally, braille-preferring voxels did not distinguish between faces and scenes (t(19) = 0.3, p = 0.79). By contrast, separate neural populations in parietal cortices responded preferentially to tactile faces and tactile places, respectively (p’s < 0.001). Face- and place-preferring neural populations responded more to tactile shapes than to braille words (t(19) = 2.4, p = 0.028), mirroring the selectivity observed in vOTC of sighted readers. These results suggest that proficient blind readers develop braille ‘word form’ responses in posterior parietal cortex.

Topic Area: PERCEPTION & ACTION: Multisensory