Identifying Individualized Neurophysiological Causal Features for Working Memory Performance: Implications for Non‐Invasive Brain Stimulation

Abstract

AbstractBackgroundNon‐invasive brain stimulation (NIBS) has been extensively used to target specific neural oscillations with the aim of improving working memory performance. However, current NIBS paradigms have two main limitations: first, lack of personalization and second, a need for a randomized controlled trial (RCT) to infer causality between targets of NIBS and subsequent performance. RCT is a powerful measure to infer causality, but its implementation is expensive, time consuming, and sometimes simply not possible. Therefore, our aim was to use computational models and observational data to discover causal relations between neural oscillations and working memory performance to identify potential targets and stimulation parameters for personalized NIBS paradigms.MethodWe used electroencephalography (EEG) data of 66 young healthy participants collected while performing a 3‐back working memory task. Using graphical causal modeling, we extracted individualized causal brain oscillations of 3‐back performance and compared the causal features between two groups: high and low performers.ResultTotal number of causal features in high performers was higher than low performers. Among the causal features, right temporal gamma oscillation was ∼5 times (z‐score = 3.87, p = 0.003) more frequently a causal feature among high performers than low performers. However, the power of causal temporal gamma oscillation was not different between the two groups.ConclusionOur findings suggest that a potential approach to improve working memory performance using NIBS is to induce more causal gamma oscillations by, for example, generating more local gamma entrainment over the right temporal cortex and not necessarily by increasing gamma power.