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Phase synchronization between theta and upper alpha oscillations in a working memory task

2005; Elsevier BV; Volume: 57; Issue: 2 Linguagem: Inglês

10.1016/j.ijpsycho.2005.03.016

1872-7697

B. Schack, Wolfgang Klimesch, Paul Sauseng,

Neural and Behavioral Psychology Studies

Motivated by findings that theta and upper alpha oscillations respond selectively to different types of memory demands, we investigated the role of phase synchronization in a memory scanning task. During retention, we found a load dependent increase in upper alpha power at O2 and P4 and a significant upper alpha:theta phase synchronization between right posterior, central and left anterior sites. During retrieval, a load dependent increase in upper alpha phase locking was observed at O2 and an increase in upper alpha:theta phase synchronization between right posterior and left anterior sites. We suggest that theta reflects central executive functions whereas upper alpha may be important for the reactivation of long-term memory codes in short-term memory. The interplay between theta and upper alpha may be reflected by phase synchronization between these frequencies.