Converging evidence for functional and structural segregation within the left ventral occipitotemporal cortex in reading

Published online September 17, 2018The ventral occipitotemporal cortex (vOTC) is crucial for recognizing visual patterns, and previous evidence suggests that there may be different subregions within the vOTC involved in the rapid identification of word forms. Here, we characterize vOTC reading circuitry using a multimodal approach combining functional, structural, and quantitative MRI and behavioral data. Two main word-responsive vOTC areas emerged: a posterior area involved in visual feature extraction, structurally connected to the intraparietal sulcus via the vertical occipital fasciculus; and an anterior area involved in integrating information with other regions of the language network, structurally connected to the angular gyrus via the posterior arcuate fasciculus. Furthermore, functional activation in these vOTC regions predicted reading behavior outside of the scanner. Differences in the microarchitectonic properties of gray-matter cells in these segregated areas were also observed, in line with earlier cytoarchitectonic evidence. These findings advance our understanding of the vOTC circuitry by linking functional responses to anatomical structure, revealing the pathways of distinct reading-related processes.This work was supported by European Molecular Biology Organization (EMBO, Short-Term Fellowship 158-2015) and Marie Sklodowska-Curie (H2020-MSCA-IF-2017-795807-ReCiModel) grants (to G.L.-U.); Spanish Ministry of Economy and Competitiveness (MINECO, PSI2015- 67353-R, SEV-2015-0490) and European Research Council (ERC, ERC-2011- ADG-295362) grants (to M.C.); and MINECO (RYC-2014-15440, PSI2012- 32093, SEV-2015-0490) and Departamento de Desarrollo Económico y Competitividad, Gobierno Vasco (PI2016-12) grants (to P.M.P.-A.)