Abstract
Although the dorsal visual pathway is traditionally associated with visuospatial processing to enable action, accumulating evidence indicates that dorsal visual areas also contribute to object perception (Freud et al., 2017). In particular, recent fMRI data suggest that the dorsal pathway contributes to shape perception by computing the spatial arrangement of object parts – a descriptor of global form (Ayzenberg & Behrmann, 2021). However, a full understanding of these computations is limited by the spatial and temporal resolution of fMRI. Here, we leverage the superior spatial and temporal resolution of stereotactic electroencephalography (sEEG), a technique that allows for direct measurement of neural activity, in a pediatric patient with 18 electrode implantations implanted across bilateral parietal cortex (256 channels). To assess whether dorsal regions display sensitivity to the spatial arrangement of object parts, the patient viewed displays wherein the spatial arrangement of object parts varied while holding the features constant or wherein the features of the parts changed while holding the spatial arrangement constant. Consistent with fMRI findings, multiple dorsal channels responded more to the spatial arrangement of parts than to the features of the parts. This finding provides converging evidence, with much finer granularity that dorsal visual regions compute representations that are crucial for shape perception, namely a representation of the spatial arrangement of object parts. Future analyses will build on these findings to test whether, for example, there are hemispheric differences in these representations and whether the global shape of object categories (e.g. guitars independent of specific type of guitar) can be decoded from these regions. Moreover, we will leverage the temporal resolution of sEEG to examine the time course of object processing in dorsal cortex. Together, these findings improve our understanding of functional specificity in visual regions and suggest an important role for dorsal cortex in facilitating object recognition.