Typical Neural Representations of Action Verbs Develop without Vision

Many empiricist theories hold that concepts are composed of sensory-motor primitives. For example, the meaning of the word run is in part a visual image of running. If action concepts are partly visual, then the concepts of congenitally blind individuals should be altered in that they lack these visual features. We compared semantic judgments and neural activity during action verb comprehension in congenitally blind and sighted individuals. Participants made similarity judgments about pairs of nouns and verbs that varied in the visual motion they conveyed. Blind adults showed the same pattern of similarity judgments as sighted adults. We identified the left middle temporal gyrus (lMTG) brain region that putatively stores visual-motion features relevant to action verbs. The functional profile and location of this region was identical in sighted and congenitally blind individuals. Furthermore, the lMTG was more active for all verbs than nouns, irrespective of visual-motion features. We conclude that the lMTG contains abstract representations of verb meanings rather than visual-motion images. Our data suggest that conceptual brain regions are not altered by the sensory modality of learning.