Presentation
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Quantification of reading circuits in the ventral occipitotemporal cortex
Poster C123 in Poster Session C, Wednesday, October 25, 10:15 am - 12:00 pm CEST, Espace Vieux-Port
Also presenting in Lightning Talks C, Wednesday, October 25, 10:00 - 10:15 am CEST, Auditorium
Yongning Lei1, Pedro M. Paz-Alonso1,2, Garikoitz Lerma-Usabiaga1,2; 1Basque Center on Cognition, Brain & Language, San Sebastián, Gipuzkoa, Spain, 2Ikerbasque, Basque Foundation for Science, Bilbao, Bizkaia, Spain
Successful reading requires neural processing and communication between different regions of the brain. There is substantial evidence that one of the regions necessary for reading is located in the ventral occipitotemporal cortex (vOTC). This region was first functionally identified and denominated visual word form area (VWFA). Recent evidence from our group combining functional, structural, and quantitative MRI has shown that the VWFA can be segregated into at least two sub-regions: one involved in visual feature extraction in the posterior occipitotemporal sulcus (pOTS), and one implicated in integrating with the language network in the middle occipitotemporal sulcus (mOTS). However, due to the heterogeneity of functional localizers used across studies, it is difficult to know if the same cortical region is being analyzed and if the results of the analyses are comparable or not. This is of critical importance to be able to compare the same regions across neurobiology of reading experiments. The aim of the present work was to develop a multimodal vOTC word recognition localizer, replicable across different labs and studies. Our experiment consisted of a dense sampled (10 times, 10 subjects) cohort, scanned in a Siemens 3T Magnetom PrismaFit scanner with a 64-channel head coil. Participants underwent four different functional MRI scans: (i) mOTS and pOTS localizer; (ii) Adapted fLoc functional localizer; (iii) Classical 8-bar retinotopic analyses, with checkers, words, and false fonts revealed inside the bars (2 repetitions each); (iv) Adapted retinotopy analyses based on preliminary results. After performing these four fMRI tasks, participants were administered quantitative MRI (qMRI), and diffusion-tensor-imaging (DWI) scans, as well as T1- and T2-weighted structural images. Results revealed at the individual subject level that combined multimodal MRI measurement can reliably segregate the vOTC reading circuits into two functional subregions, across different sessions. Furthermore, we developed a shorter acquisition sequence to identify vOTC reading circuits that will be made available to the scientific community. Moreover, preliminary results using machine learning techniques showed that the same regions can be localized maintaining around ¾-s of the intra-subject variability. In sum, here we propose a new protocol to harmonize inter-lab and inter-experimental visual word recognition and reading studies, which is critical to advance our understanding of the role of the vOTC in neurobiology of reading.
Topic Areas: Reading, Methods