In Journal of neuroscience methods
BACKGROUND : Temporal principal component analysis (tPCA) has been widely used to extract event-related potentials (ERPs) at group level of multiple subjects ERP data and it assumes that the underlying factor loading is fixed across participants. However, such assumption may fail to work if latency and phase for one ERP vary considerably across participants. Furthermore, effect of number of trials on tPCA decomposition also has not been systematically examined, especially for the within-subject PCA.
NEW METHOD : We reanalyzed a real ERP data of an emotional experiment using tPCA to extract N2 and P2 from single-trial EEG of an individual. We also explored the influence of the number of trials (consecutively increased from 10 to 42 trials) on PCA decomposition by comparing temporal correlation, the statistical result, Cronbach's alpha, spatial correlation of both N2 and P2 for the proposed method with the conventional time-domain analysis, trial-averaged group PCA, and single-trial-based group PCA.
RESULTS : The results of the proposed method can enhance the spatial and temporal consistency. We could obtain the stable N2 with few trials (about 20) for the proposed method, but, for P2, approximately 30 trials were needed for all methods.
COMPARISON WITH EXISTING METHOD(S) : About 30 trials for N2 were required and the reconstructed P2 and N2 were poor correlated across participants for the other three methods.
CONCLUSION : The proposed approach may efficiently capture variability of one ERP from an individual that cannot be extracted by the group PCA analysis.
Zhang Guanghui, Li Xueyan, Lu Yingzhi, Tiihonen Timo, Chang Zheng, Cong Fengyu
2022-Dec-15
Back-projection, Event-related potentials, Individual subject, Principal component analysis, Single-trial analysis
