Dissociating the representation of action- and sound-related concepts in middle temporal cortex.

Modality-specific models of conceptual memory propose close links between concepts and the sensory-motor systems. Neuroimaging studies found, in different subject groups, that action-related and sound-related concepts activated different parts of posterior middle temporal gyrus (pMTG), suggesting a modality-specific representation of conceptual features. However, as these different parts of pMTG are close to each other, it is possible that the observed anatomical difference is merely related to interindividual variability. In the present functional magnetic resonance imaging study, we now investigated within the same participant group a possible conceptual feature-specific organization in pMTG. Participants performed lexical decisions on sound-related (e.g., telephone) and action-related (hammer) words. Sound words elicited higher activity in anterior pMTG adjacent to auditory association cortex, but action-related words did so in posterior pMTG close to motion sensitive areas. These results confirm distinct conceptual representations of sound and action in pMTG, just adjacent to the respective modality-specific cortices.