To date, the physiological mechanisms that support visual working memory (WM) remain poorly understood. One reason is that a typical WM task is unable to distinguish between multiple underlying sub-processes (e.g. perception, attentional control, consolidation/storage), which map onto different neural signals. We used a modified change detection task sequence to examine electroencephalography (EEG) correlates of perception, attentional engagement, and memory consolidation/storage in a sample of 42 individuals. Additionally, we applied a novel analysis approach designed to disentangle the aperiodic and oscillatory components of the EEG signal during the prestimulus and the poststimulus period. We observed: (i) aperiodic parameters were significantly elevated during the pretrial period of the memory consolidation/storage task variant compared to the perception and attention task variants; (ii) prestimulus aperiodic parameters and oscillatory alpha were significantly associated with WM capacity and attentional control, respectively; and (iii) unexpectedly, higher oscillatory alpha was associated with better attentional engagement across participants, as well as within participants. Poststimulus aperiodic parameters and alpha oscillations showed a load-dependent effect in the poststimulus period; however, these parameters were not associated with task performance. This work suggests that aperiodic and alpha oscillatory elements of the EEG signal may serve unique roles in WM capacity and attention.
Erickson et al. (Tue,) studied this question.