Activation of human language processing brain regions after the presentation of random letter strings demonstrated with event-related functional magnetic resonance imaging

This study addresses the question, to what extent the processing of meaningless random letter strings involves classical language related brain regions. Using event-related functional magnetic resonance imaging (fMRI), which allows random stimulus presentation, we could demonstrate activation in the left inferior frontal gyrus, the left superior temporal gyrus, left parietal and occipita I regions after the presentation of random letter strings com pared to real words. The activation in these classical language related brain areas reflects an intense lexical evaluation process of the meaningless stimuli. Real words contrasted with random letter strings activated the left angular gyrus, bilateral precuneus and the left posterior cingulate gyrus, which may reflect the access of higher semantic associations. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.