Dissociating frequency and animacy effects in visual word processing: An fMRI study

In an fMRI investigation of the neural representation of word frequency and animacy, participants read high- and low-frequency words within living and nonliving semantic categories. Both temporal (left fusiform gyrus) and parietal (left supramarginal gyrus) activation patterns differentiated between animal and tool words after controlling for frequency. Activation patterns in a smaller ventral temporal region, a subset of the voxels identified in the animacy contrast, differentiated between high- and low-frequency words after controlling for animacy. Activation patterns in the larger temporal region distinguished between high- and low-frequency words just as well as patterns within the smaller region. However, in analyses by animacy category, frequency effects in these temporal regions were significant only for tool, not for animal, words. Thus, lexical word frequency information and semantic animacy category information are conjointly represented in left fusiform gyrus activation patterns for some, but not all, concrete nouns.