Object Category and Retinotopic Location Differentially Modulate Temporal Dynamics of Category Selective Regions of Ventral Temporal Cortex

Retinotopy as a putative organizing principle extends throughout high-level visual and category selective areas of ventral temporal cortex, but the dynamic temporal emergence of retinotopic information in these areas is not well understood. Given that individual category selective regions contribute to multiple processing states over time (Ghuman and Martin 2019), an open question is whether the retinotopic sensitivity in these areas demonstrate a similar and related temporal profile. To examine this question, we investigated the time course by which category and retinotopic information is represented in high-level visual areas that are tuned to specific categories. We collected intracranial electroencephalography (iEEG) data from face and word sensitive contacts throughout ventral temporal cortex as patients viewed face and word stimuli arranged around fixation. Results from a series of temporally-resolved multivariate classification analyses demonstrate that both position and category information are represented in category-sensitive areas around 100 ms after stimulus onset. Furthermore, position modulates the degree of category representation via foveal and contralateral visual field biases, and face sensitive contacts show enhanced position sensitivity to face stimuli but not word stimuli. Taken together, these results show a fine-grained relationship between retinotopy and object category that can be used to begin teasing apart the spatiotemporal dynamics in visual cortex.