Mitchell_VWFA_methods_2025

Ventral Occipital Temporal Cortex (VOTC) is home to a mosaic of categorically-selective functional regions that respond to visual stimuli. Within left VOTC lies the Visual Word Form Area (VWFA) - a text-selective region that develops as an individual learns to read. While there is consistency in the general location of text-selective responses - within the posterior portion of the occipitotemporal sulcus (OTS) - there is also substantial variability across individuals in the size and precise anatomical location. Moreover, there is an ongoing debate over the extent to which the VWFA a) encodes the visual features of text, versus b) is driven by the task of reading. Using functional magnetic resonance imaging, we scanned adults and children as they completed two tasks while viewing text, pseudo fonts, faces, objects, limbs. Experimental tasks were: (1) a fixation task where they were instructed to ignore the stimuli while making psychophysical judgements on the fixation dot; (2) a one-back task where they were instructed to attend to the stimuli and detect repeats. We found that a consistent VWFA location could be identified on each individual’s cortical surface using either task. At the same time, the response to text during the one-back task evoked a larger territory of text-selective response (leading to a larger ROI) than the fixation task. However, when averaged in template space, text-selective cortex could not be identified due to variability in the relative locations of text-, face-, object-, and limb-selective cortex. Thus, for both children and adults, a text-selective region (i.e., VWFA) can be localized on the individual cortical surface. This resulting region consistently responds to text irrespective of cognitive task, but text-selective responses are masked when averaged in template space due to variability in the exact configuration of category-selective regions.