RIGHT-HEMISPHERE ACTIVATION DURING INDIRECT SEMANTIC PRIMING - EVIDENCE FROM EVENT-RELATED POTENTIALS

Healthy subjects performed a lexical decision task in a semantic primi ng paradigm while event-related potentials (ERPs) were recorded from 6 4 channels. Semantic distance between prime and target was varied by i ncluding directly, indirectly, and nonrelated word pairs. At centro-pa rietal electrodes an N400 to nonrelated pairs was elicited bilaterally which was sensitive only to direct, but not to indirect semantic prim ing. These N400 priming effects were mirrored by the RT data. At infer ior fronto-temporal sites directly related words showed ERP priming ef fects over both hemispheres. However, indirectly related words only el icited ERP priming effects over the right hemisphere. These results su pport the hypothesis that the right hemisphere semantic system is invo lved in processing of remote semantic information. (C) 1998 Academic P ress.