Distinct cortical areas for names of numbers and body parts independent oflanguage and input modality

Some models of word comprehension postulate that the processing of words pr esented in different modalities and languages ultimately converge's toward common cerebral systems associated with semantic-level processing and that the localization of these systems may vary with the category of semantic kn owledge being accessed. We used functional magnetic resonance imaging to in vestigate this hypothesis with two categories of words, numerals, and body parts, for which the existence of distinct category-specific areas is debat ed in neuropsychology. Across two experiments, one with a blocked design an d the other with an event-related design, a reproducible set of left-hemisp heric parietal and prefrontal areas showed greater activation during the ma nipulation of topographical knowledge about body parts and a right-hemisphe ric parietal network during the manipulation of numerical quantities. These results complement the existing neuropsychological and brain-imaging liter ature by suggesting that within the extensive network of bilateral parietal regions active during both number and body-part processing, a subset shows category-specific responses independent of the language and modality of pr esentation. (C) 2000 Academic Press.