Modulation of the FFA and PPA by language related to faces and places

Abstract

Does sentence comprehension related to faces modulate activity in the fusiform face area (FFA) and does sentence comprehension related to places modulate activity in the parahippocampal place area (PPA)? We investigated this question in an fMRI experiment. Participants listened to sentences describing faces. places, or objects. with the latter serving as a control condition. In a separate run, we localized the FFA and PPA in each participant using a perceptual task. We observed a significant interaction between the region of interest (FFA vs. PPA) and sentence type (face vs. place). Activity in the left FFA was modulated by face sentences and in the left PPA was modulated by place sentences. Surprisinaly, activation in each region of interest was reduced when listening to sentences requiring semantic analysis related to that region's domain specificity. No modulation was found in the corresponding right hemisphere ROIs. We conclude that processing sentences may involve inhibition of some visual processing areas in a content-specific manner. Furthermore, our data indicate that this semantic-based modulation is restricted to the left hemisphere. We discuss how these results may constrain neural models of embodied semantics.