Localization of early syntactic processes in frontal and temporal corticalareas: A magnetoencephalographic study

Previous electrophysiological studies had found an early anterior negativit y often with a maximum over the left hemisphere to correlate with the early detection of an error in the syntactic structure of a sentence. In this pa per, the cortical structures involved in such early syntactic parsing proce sses were localized using MEG. Subjects were presented with acoustic senten ces and asked to judge their syntactic correctness. The subjects' brain res ponses to syntactic violations were recorded with a 148-channel whole-head magnetometer. Dipole source localization was performed using a realisticall y shaped standard volume conductor model with fMRI constraints. The results show that the early syntactic parsing processes are supported by temporal regions, possibly the planum polare, as well as by fronto-lateral regions. As indicated by the resultant dipole strengths, these regions are activated bilaterally with a dominance in the left hemisphere for four out of the fi ve subjects. The contribution of the left temporal regions to the early syn tactic processes seems to be larger than that of the left fronto-lateral re gions. Hum. Brain Mapping 11:1-11, 2000. (C) 2000 Wiley-Liss, Inc.