Alternating Zones Selective to Faces and Written Words in the Human Ventral Occipitotemporal Cortex

Abstract

Recognition of faces and written words is associated with category-specific brain activation in the ventral occipitotemporal cortex (vOT). However, topological and functional relationships between face-selective and word-selective vOT regions remain unclear. In this study, we collected data from patients with intractable epilepsy who underwent high-density recording of surface field potentials in the vOT. "Faces" and "letterstrings" induced outstanding category-selective responses among the 24 visual categories tested, particularly in high-γ band powers. Strikingly, within-hemispheric analysis revealed alternation of face-selective and letterstring-selective zones within the vOT. Two distinct face-selective zones located anterior and posterior portions of the mid-fusiform sulcus whereas letterstring-selective zones alternated between and outside of these 2 face-selective zones. Further, a classification analysis indicated that activity patterns of these zones mostly represent dedicated categories. Functional connectivity analysis using Granger causality indicated asymmetrically directed causal influences from face-selective to letterstring-selective regions. These results challenge the prevailing view that different categories are represented in distinct contiguous regions in the vOT.

Category-Selectivity in Human Visual Cortex Follows Cortical Topology: A Grouped icEEG Study

“…Notably, regions demonstrating word-selectivity are clustered around the intersection of the occipito-temporal sulcus (OTS) and the anterior MFS ( Fig 6 ), consistent with prior studies of word selectivity that have localized cortical regions sensitive to orthographic stimuli to the general vicinity of the OTS (i.e. the visual word-form area) [ 13 , 17 , 45 , 76 – 78 , 112 , 127 ]. Given that word, tool, animate, and face stimuli are typically dependent on central vision [ 23 , 43 , 44 , 46 ], the co-localization of word-selectivity with these other categories remains consistent with our original prediction that word-selectivity should be observed in regions with foveal bias.…”

“…Because 5 categories in all were evaluated, for each category j , N will be equal to 4. In this fashion, each electrode could be judged selective for multiple categories [ 112 ].…”

A vision of graded hemispheric specialization

“…), and the converse pattern holds true for faces. A similar pattern was observed in a recent study using high‐density recording of surface field potentials in the ventral occipitotemporal cortex of patients with intractable epilepsy, revealing striking within‐hemisphere interdigitation of face‐ and letter‐string–selective zones . Together, these findings undermine the argument for strict lateralization of face and word representations.…”

Decoding English Alphabet Letters Using EEG Phase Information

“…Decoding the phase patterns in theta and alpha oscillations provided relatively higher discrimination accuracy than did the delta, beta and gamma band oscillations. Previous studies suggested that the ventral occipital-temporal (vOT) cortex is involved in the perception of visually presented objects and written words (Dahaene, 1995 ; Price and Devlin, 2011 ; Matsuo et al, 2015 ). Our decoding analysis showed a higher classification power for electrodes placed in occipital-temporal regions compared to other regions, although we should keep in mind that EEG electrodes do not necessarily pick up activity directly under the electrodes.…”