Poster C122, Sunday, March 26, 5:00 – 7:00 pm, Pacific Concourse
Large scale comparison of retinotopic and category selective maps throughout human visual cortex
Edward Silson1, Iris Groen1, Caitlin Van Wicklin1, Chris Baker1; 1Section on Learning and Plasticity, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health
Historically, category-selectivity and retinotopy have been considered as two largely independent organizing principles of human visual cortex, but recent work questions this independence. Here, using functional magnetic resonance imaging (fMRI) we conducted extensive mapping of both retinotopy and category-selectivity in a large group of participants (n=35). Retinotopy was mapped using the population receptive field mapping technique allowing us to define multiple retinotopic maps including V1-V4, LO1, LO2, V3A/B, V7/IPS0. Category-selectivity was mapped by presenting participants with images of bodies, buildings, faces, objects, scenes & scrambled objects, allowing us to define face-, scene- and object-selective regions on both the lateral and ventral surfaces of occipitotemporal cortex. First, across participants we found clear evidence for category-selectivity within early retinotopic visual areas, suggesting that category-level representations can be detected in visual cortex earlier than typically assumed. Second, consistent with our earlier work (Silson et al, 2015, 2016), we found reliable retinotopic representations within category-selective regions, demonstrating a largely preserved representation of visual space within these regions despite contrasting category-selective response profiles. Finally, we compared the patterns of response within category-selective areas and retinotopic maps after matching for visual field coverage. Despite largely equivalent representations of visual space, the patterns of selectivity differed substantially between retinotopic regions and category-selective areas, even for adjacent regions. These different response patterns, despite similar visual field representations, suggest a strong discontinuity in the representation of visual information between more posterior retinotopic and more anterior category-selective regions.
Topic Area: PERCEPTION & ACTION: Vision