Phase synchronization between theta and upper alpha oscillations in a working memory task.
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.
Schack
B
B
Institute of Medical Statistics, Computer Sciences and Documentation, Medical Faculty of the Friedrich Schiller University Jena, Germany.
Klimesch
W
W
Sauseng
P
P
D000328:Adult; D000513:Alpha Rhythm; D001519:Behavior; D001921:Brain / Q000502:physiology; D001931:Brain Mapping; D003344:Cortical Synchronization; D004569:Electroencephalography; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008568:Memory / Q000502:physiology*; D009991:Oscillometry; D011930:Reaction Time; D012153:Retention, Psychology / Q000502:physiology; D013826:Theta Rhythm; D013997:Time Factors