A neural basis for category and modality specificity of semantic knowledge

Prevalent theories hold that semantic memory is organized by sensorimotor m odality (e.g., visual knowledge, motor knowledge). While some neuroimaging studies support this idea, it cannot account for the category specific (e.g ., living things) knowledge impairments seen in some brain damaged patients that cut across modalities. In this article we test an alternative model o f how damage to interactive, modality-specific neural regions might give ri se to these categorical impairments. Functional MRI was used to examine a c ortical area with a known modality-specific function during the retrieval o f visual and non-visual knowledge about living and non-living things. The s pecific predictions of our model regarding the signal observed in this area were confirmed, supporting the notion that semantic memory is functionally segregated into anatomically discrete, but highly interactive, modality-sp ecific regions. (C) 1999 Published by Elsevier Science Ltd. All rights rese rved.