Mindfulness meditation has been shown to improve working memory (WM). However, brain activity underpinning these improvements is underexplored. In meditation-naïve individuals, increased fronto-midline theta and parieto-occipital alpha oscillations, and steeper 1/f aperiodic activity during WM correlate with better WM performance. Resting theta and alpha oscillations have been found to differ in meditators, but WM-related oscillations and 1/f aperiodic activity have not been examined. Additionally, WM-related event-related-potentials (ERPs) are modulated by attention, which is enhanced by mindfulness meditation, so these neural measures are candidate explanations for WM improvement in mindfulness meditators.
We recorded electroencephalography (EEG) from 29 meditation-naïve controls and 29 experienced mindfulness meditators during a Sternberg WM task and compared theta, alpha and 1/f aperiodic activity during the WM delay, and ERPs time-locked to the WM probe.
Compared to controls, meditators demonstrated greater WM accuracy (p = 0.008, Cohen’s d = 0.688), earlier left-temporal ERP responses and a more frontal distribution of activity (FDR-p = 0.0186, η2 = 0.0903), as well as a reduction in overall neural response strength (FDR-p = 0.0098, η2 = 0.1251). A higher proportion of meditators showed theta oscillations during the WM delay, but no other differences in theta, alpha or 1/f aperiodic activity were present.
Results suggest that increased WM performance in mindfulness meditators might not result from higher amplitudes of typical WM activity, but instead from an alternative pattern of brain region engagement during WM decision making, allowing more accurate responses with less neural activation (perhaps reflecting increased neural efficiency).