ABSTRACT
Magnetoencephalography (MEG) measured subjects' brain responses during a lexical decision task. The words employed come from six frequency categories, which were defined in terms of a linear decrease in log-frequency. Although frequency effects in reaction-time are well-documented in studies of lexical access, a neural component whose latency predicts reaction time has not been discovered. This study identifies an MEG component (the M350) whose latency mirrors the frequency-effect.
Subject(s)
Magnetoencephalography , Speech/physiology , Adult , Behavior/physiology , Decision Making/physiology , Evoked Potentials/physiology , Female , Humans , Male , Reaction Time/physiologyABSTRACT
Despite numerous aphasia and functional imaging studies, the exact correlation between cortical language areas and subcomponents of the linguistic system has not been established. Here, we used functional MRI to identify cortical areas specifically involved in syntactic processing. An experimental design contrasted sentences containing grammatical errors with sentences containing spelling errors. The ungrammatical sentences produced more activation in cortical language areas than did the sentences with spelling errors, and the difference in activation was significantly greater in Broca's area than in Wernicke's area or in the angular gyrus/supramarginal gyrus. The present findings provide direct evidence of a syntactic specialization for Broca's area and establish the existence of distinct modules for our knowledge of language.
