A limited number of regions specific to input modality are activated by the auditory and visual presentation of single words. These regions include primary auditory and visual cortex, and modality-specific higher order regions that may be performing computations at a word level of of analysis. Positron emission tomographic (PET) measures of brain blood flow change are used to map the functioning of the human brain during processing of individual words or lexical items. It is found that the passive presentation of word stimuli activates several brain regions. These regions are modality-specific in that there is no overlap in the regions activated by auditory input and those activated by visual input. For both modalities, there is activation in the primary and extraprimary regions. The extraprimary regions are not activated by other types of sensory input, making them candidates for higher level coding appropriate to lexical (word) level analysis. The existence of multiple areas of activation in the occiptal lobe is consistent with models of early visual word processing that postulate feature, letter, and word levels of analysis.
|Number of pages||2|
|State||Published - Dec 1 1987|