FIRST-PASS VERSUS 2ND-PASS PARSING PROCESSES IN A WERNICKES AND A BROCAS APHASIC - ELECTROPHYSIOLOGICAL EVIDENCE FOR A DOUBLE DISSOCIATION

The present paper is a first attempt to integrate the classical brain lesion behavioral impairment approach of functional neuroanatomy and t he electrophysiological brain mapping approach in the domain of syntac tic processing. In a group of normal age matched controls we identifie d three electrophysiological components previously observed in correla tion with language comprehension processes: an early left anterior neg ativity normally seen in correlation with syntactic first-pass parsing processes (ELAN), a centroparietal negativity seen in correlation wit h processes of lexical-semantic integration (N400), and a late centrop arietal positivity observed in correlation with secondary syntactic pr ocesses of reanalysis and repair (P600). The early left anterior negat ivity was absent in a patient with an extended lesion in the anterior part of the left hemisphere sparing the temporal lobe, although the la te centroparietal positivity and the centroparietal N400 were present. In a patient with a left temporal-parietal lesion the early left ante rior negativity was found to be present, whereas the N400 component wa s absent. These findings suggest that first-pass parsing and secondary processes are subserved by distinct brain systems. (C) 1998 Academic Press.