Interpreting sensory and cognitive signals in the cortical reading network

Abstract

Voxels in the visual cortex contain neurons that are responsive to small regions of the visual field; these regions can be quantified using population receptive field (pRF) analysis. We measured pRFs using several types of patterns: words, visually matched false-fonts, and visually dissimilar checker patterns. In visual field maps pRF estimates using words and false-fonts are similar, but pRF estimates using checkers differ substantially. The pattern of results in the contiguous ventral occipito-temporal reading circuitry is different: word pRF estimates differ from false-fonts and checkers. These findings were replicated at two research sites. We explain these results with a qualitative model, where the response differences in the visual field maps arise from sensory signals, and the differences in the reading circuitry arise from the integration of sensory and cognitive signals.