Neurophysiological aspects of language processing.

Neurophysiological studies of language processing in the intact brain have identified 3 major event-related potential (ERP) components correlating with different aspects of language: (1) an early left anterior negativity (ELAN) obtained in correlation with early syntactic processes, primarily processes of structuring the language input, (2) a centroparietal negativity around 400 ms (N400) reflecting lexicalsemantic integration processes, and (3) a late centroparietal positivity (P600) observed in correlation with secondary syntactic processes such as reanalysis and repair. These components manifest themselves approximately around 200 ms, 400 ms and 600 ms post onset of a critical word. Their variation in latency and magnitude can be used as a diagnostic criterion for language impairment.