The role of theta and alpha oscillations for language comprehension in thehuman electroencephalogram

The hypothesis is tested, whether increasing language processing demands dr aw on the capacity of working memory thereby leading to an increase In thet a band power. Previous research has shown that theta reflects working memor y whereas upper alpha semantic memory demands. Sentences were presented in four chunks in a reading and a semantic task. In the latter, subjects had t o find a superordinate concept to a noun presented in the third chunk. The data show an increase in theta during sentence processing which was signifi cantly smaller in the semantic task. In contrast, the upper alpha band exhi bited a significantly larger change in band power during the semantic task and that time window in which subjects searched for the superordinate conce pt. Thus, we conclude that semantic processing does not draw selectively on the capacity of working memory and that different linguistic processes hav e no direct influence on theta oscillations. (C) 2001 Elsevier Science Irel and Ltd. All rights reserved.