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Abstract■ Previous studies have provided evidence for a tool-selective region in left lateral occipitotemporal cortex (LOTC). This region responds selectively to pictures of tools and to characteristic visual tool motion. The present human fMRI study tested whether visual experience is required for the development of tool-selective responses in left LOTC. Words referring to tools, animals, and nonmanipulable objects were presented auditorily to 14 congenitally blind and 16 sighted participants. Sighted participants additionally viewed pictures of these objects. In whole-brain group analyses, sighted participants showed toolselective activity in left LOTC in both visual and auditory tasks. Importantly, virtually identical tool-selective LOTC activity was found in the congenitally blind group performing the auditory task. Furthermore, both groups showed equally strong toolselective activity for auditory stimuli in a tool-selective LOTC region defined by the picture-viewing task in the sighted group. Detailed analyses in individual participants showed significant tool-selective LOTC activity in 13 of 14 blind participants and 14 of 16 sighted participants. The strength and anatomical location of this activity were indistinguishable across groups. Finally, both blind and sighted groups showed significant resting state functional connectivity between left LOTC and a bilateral frontoparietal network. Together, these results indicate that toolselective activity in left LOTC develops without ever having seen a tool or its motion. This finding puts constraints on the possible role that this region could have in tool processing and, more generally, provides new insights into the principles shaping the functional organization of OTC. ■

Classical animal visual deprivation studies and human neuroimaging studies have shown that visual experience plays a critical role in shaping the functionality and connectivity of the visual cortex. Interestingly, recent studies have additionally reported circumscribed regions in the visual cortex in which functional selectivity was remarkably similar in individuals with and without visual experience. Here, by directly comparing resting-state and task-based fMRI data in congenitally blind and sighted human subjects, we obtained large-scale continuous maps of the degree to which connectional and functional "fingerprints" of ventral visual cortex depend on visual experience. We found a close agreement between connectional and functional maps, pointing to a strong interdependence of connectivity and function. Visual experience (or the absence thereof) had a pronounced effect on the resting-state connectivity and functional response profile of occipital cortex and the posterior lateral fusiform gyrus. By contrast, connectional and functional fingerprints in the anterior medial and posterior lateral parts of the ventral visual cortex were statistically indistinguishable between blind and sighted individuals. These results provide a large-scale mapping of the influence of visual experience on the development of both functional and connectivity properties of visual cortex, which serves as a basis for the formulation of new hypotheses regarding the functionality and plasticity of specific subregions.

Knowledge of object shape is primarily acquired through the visual modality but can also be acquired through other sensory modalities. In the present study, we investigated the representation of object shape in humans without visual experience. Congenitally blind and sighted participants rated the shape similarity of pairs of 33 familiar objects, referred to by their names. The resulting shape similarity matrices were highly similar for the two groups, indicating that knowledge of the objects' shapes was largely independent of visual experience. Using fMRI, we tested for brain regions that represented object shape knowledge in blind and sighted participants. Multivoxel activity patterns were established for each of the 33 aurally presented object names. Sighted participants additionally viewed pictures of these objects. Using representational similarity analysis, neural similarity matrices were related to the behavioral shape similarity matrices. Results showed that activity patterns in occipitotemporal cortex (OTC) regions, including inferior temporal (IT) cortex and functionally defined object-selective cortex (OSC), reflected the behavioral shape similarity ratings in both blind and sighted groups, also when controlling for the objects' tactile and semantic similarity. Furthermore, neural similarity matrices of IT and OSC showed similarities across blind and sighted groups (within the auditory modality) and across modality (within the sighted group), but not across both modality and group (blind auditory-sighted visual). Together, these findings provide evidence that OTC not only represents objects visually (requiring visual experience) but also represents objects nonvisually, reflecting knowledge of object shape independently of the modality through which this knowledge was acquired.