[Evoked spectral EEG power during presentation of pseudowords and words from "animate" and "inanimate" categories]

Pseudowords and words of "animate" and "inanimate" categories were shown to healthy young adults (14 women and 9 men) in three series. In the first series, subjects were just reading presented verbal stimuli (words and pseudowords), in the second series, they had to click a mouse button in response to presentation of a word, and in the third series they clicked a button when pseudowords were presented. Presentation of words and pseudowords caused desynchronization of the alpha rhythm and synchronization of the theta rhythm. Early synchronization (50-250 ms) was stronger for pseudowords and words of "animate" category during passive perception of stimulus. The middle synchronization period (250-800 ms) was stronger in projections of Broca's and Wernicke's areas. The relevance of the stimuli led to an increase in desynchronization and reduction of early and late (800-1500 ms) synchronization periods after presentation of both words and pseudowords. For words of "animate" categories, the synchronization of the theta rhythm was more pronounced in the early periods, and for words of "inanimate" categories, the theta rhythm synchronization was more distinct in the middle periods.