Dissociated face- and word-selective intracerebral responses in the human ventral occipito-temporal cortex

Abstract

The extent to which faces and written words share neural circuitry in the human brain is actively debated. Here, we compare face-selective and word-selective responses in a large group of patients (N = 37) implanted with intracerebral electrodes in the ventral occipito-temporal cortex (VOTC). Both face-selective (i.e., significantly different responses to faces vs. non-face visual objects) and word-selective (i.e., significantly different responses to words vs. pseudofonts) neural activity is isolated with frequency-tagging. Critically, this sensitive approach allows to objectively quantify category-selective neural responses and disentangle them from general visual responses. About 70% of significant electrode contacts show either face-selectivity or word-selectivity only, with the expected right and left hemispheric dominance, respectively. Spatial dissociations are also found within core regions of face and word processing, with a medio-lateral dissociation in the fusiform gyrus (FG) and surrounding sulci, respectively. In the 30% of overlapping face- and word-selective contacts across the VOTC or in the FG and surrounding sulci, between-category-selective amplitudes (faces vs. words) show no-to-weak correlations, despite strong correlations in both the within-category-selective amplitudes (face–face, word–word) and the general visual responses to words and faces. Overall, these observations support the view that category-selective circuitry for faces and written words is largely dissociated in the human adult VOTC.

Measuring self-similarity in empirical signals to understand musical beat perception

“…"-* ) is the standard deviation across the neighboring bins. This approach has been widely used in the frequency-tagging literature, as it offers a straightforward way to statistically test whether the response stands out significantly from the noise in the recorded signal (Liu-Shuang et al, 2014;Jonas et al, 2016;Lochy et al, 2018;Volfart et al, 2020;Hagen et al, 2021).…”

Domain Specificity vs. Domain Generality: The Case of Faces and Words

“…This area—the “visual word form area” (VWFA)—displays a higher activation for written words than for consonant strings ([ 41 ]; see also [ 42 , 43 , 44 , 45 ]). The opposite lateralization for faces and words has been argued to support domain specificity for these object categories [ 46 , 47 ]. Opposite lateralization for faces and words has been framed to reflect the existence of independent and selective regions designed to process faces and words (i.e., in the right and left hemisphere, specifically; henceforth RH and LH).…”

Understanding structure–function relationships in the mammalian visual system: part one

“…Komatsu et al (2021) provide the first report about the anatomical connections of a specific region of the inferotemporal cortex in macaque monkeys, where neurons selectively respond to the glossiness of visual objects. Hagen et al (2021) explore a different aspect of the organization of the ventral stream by investigating the spatial dissociation of face-and word-selective responses in the human VOTC, based on intracranial electroencephalographic recordings. Caffarra et al (2021) review the literature on structural and functional studies of human word-selective visual cortex and discuss its implications in understanding the organization of human VOTC and reading circuitry.…”