Abstract
Distributed responses to visual categories as well as category-selective regions in human ventral temporal cortex (VTC) are anatomically consistent across participants. This consistency has been theorized to be driven by basic organizational principles including eccentricity bias, size, curvilinearity, and animacy. Differentiating these theories requires examining the effects of learning a new visual category in childhood that differs from other categories along these dimensions. Here, we examined how learning Pokémon—a novel stimulus category from the popular Nintendo game that is foveal, linear, and animate—affects distributed responses in VTC. We scanned 11 subjects who, starting at age 5-7, began life-long visual experience with Pokémon, and 11 matched Pokémon-novice participants in a blocked fMRI experiment containing Pokémon, cartoons, animals, faces, bodies, cars, corridors, and words while performing an oddball task. Both groups were matched for experience with cartoons, and demonstrated similar cartoon decodability from mutlivoxel VTC responses (45±10%). Interestingly, we found significant decodability for Pokémon from VTC of experienced (60 ± 15%), but not novice subjects (22 ± 10%). In addition to normal face and corridor response patterns, experienced subjects demonstrated anatomically consistent and unique distributed patterns for Pokémon, with enhanced selectivity in the OTS. Using independent raters and software for determining image statistics, we quantified image properties of face, corridor, and Pokémon stimuli for animacy, size, curvilinearity, and eccentricity. Notably, the ordering of these 3 categories along these axes matched the ordering of distributed responses on cortex only for the eccentricity axis. Pokémon, faces and corridors were organized on a lateral-to-medial VTC axis that was coupled with the underlying eccentricity bias. Prolonged visual experience with a new object category during childhood sculpts distributed patterns in high-level visual cortex. Importantly, this study demonstrates eccentricity of the retinal image determines the development of the organization of distributed cortical responses in high-level visual cortex.
Meeting abstract presented at VSS 2018