Abstract
A fundamental property of neurons in the visual system is that they have receptive fields that process visual information in spatially restricted regions of visual space. Little, however, is known about their development. While high-level visual areas involved in reading and face recognition show a protracted development in humans, it is unknown if this development is associated with changes to receptive fields, and if so, at what stages of the visual hierarchy they occur. To answer these questions, we estimate the population receptive field (pRF) of all voxels in the visual system in 26 typical children (5-12 years) and 26 adults (22-27 years) and compared across age groups. Participants took part in two fMRI experiments: (1) retinotopic mapping with bars containing black and white checkerboards to delineate retinotopic areas and estimate pRFs, and (2) a functional localizer containing faces, words, bodies, places, and objects to map high-level regions. In the ventral stream, we find no significant difference across age groups in polar angle, eccentricity, pRF size, or visual field coverage in areas V1-VO1 (Figure 1A). In contrast, we found differential development of pRFs of face- and word-selective regions across hemispheres. In the right hemisphere, pRFs and coverage in face-selective cortex become more foveally biased from childhood to adulthood, while word-selective cortex becomes less so. In the left hemisphere, this pattern is reversed (Figure 1B). We link this pRF development to behavior, collecting measurements of fixation patterns on faces and words outside the scanner. We find an increased foveal bias on words and faces in adult relative to child participants (Figure 1C). These results thus suggest a differential development of pRF and visual field coverage in face and word selective regions across hemispheres, which may importantly be driven by changes in viewing experience across development.
Meeting abstract presented at VSS 2017