Beta Desynchronization Mediates The Impact Of Internally Directed Attention In A Dual-Task Working Memory Paradigm

Internally directed attention (IDA), whether spontaneous or intentional, has been associated with impaired performance on externally directed cognitive tasks. Yet, the neurophysiological mechanisms underpinning this disruption remain poorly understood. In the present study, we characterized the neural correlates of IDA and identified how they impact on performance in a color-recall working memory task using electroencephalography (EEG). Participants performed a novel dual-task paradigm involving either self-referential (IDA) or perceptual processing of adjectives, involving externally directed attention (EDA) followed by a color-recall task. IDA enhanced late positive potentials (LPP) in EEG over medial-frontal electrodes as a marker of sustained affective and self-referential engagement. Time-frequency analyses further revealed increased event-related desynchronization in alpha and beta bands during stimulus encoding in the IDA condition, as well as increased alpha synchronization during the delay period, consistent with internal attention maintenance. To capture trial-level variability in task performance, we applied conditional quantile regression on the single trial data. Results showed that beta desynchronization in interaction with condition type during encoding influenced performance significantly in trials with low errors, whereas trials with high error in color recall were better explained by increased reaction times. These findings provide converging electrophysiological evidence for distinct neural signatures of internally directed attention and highlight their behavioral consequences in working memory performance.