Abstract
During recognition processes of visual working memory it can be necessary to match incoming sensory information with retained memory contents. This study aimed to investigate the underlying electrophysiological correlates of memory matching process based on EEG oscillatory phase synchronization analysis. Twenty-three healthy subjects completed a delayed match to sample task in which items stored in visualspatial short-term memory had to be compared with match or non-match probe items. The results show that this matching process of top-down memory representation and bottom-up visual information is reflected by transient phase-synchronization over parieto- occipital regions between theta (4 – 8 Hz) and high gamma (50 – 70 Hz) oscillations 150 – 200 ms after probe presentation. Furthermore, non-matching of information demands higher cognitive resources for maintaining and manipulating memory representations with new object information as reflected in large-scale theta and gamma phase synchronization.