The relationship between theta-gamma coupling and spatial memory ability in older adults.

Although theta-gamma coupling is known to reflect memory-related processes, it is unclear whether it has a relationship with memory ability. Here, we investigated the relationship between theta phase and gamma power coupling (TGC) and scores obtained regarding memory tasks. Thirty-one older subjects performed a spatial delayed match-to-sample task (SDMST) during EEG recording. We also evaluated performance on the delayed figure recall (DFR) and delayed verbal recall (DVR) tasks regarding memory ability. Partial correlation analysis (controlled for age) demonstrated that increases in TGC in the parietal area were significantly correlated with increases in the DFR scores obtained. In addition, TGC was significantly correlated with the accuracy rate of the SDMST. Our results indicate that TGC could be a useful biophysiological marker of memory ability.