Neurophysiological Signatures of Working Memory Binding and Updating during Encoding

Working memory (WM) has been extensively studied in cognitive psychology and there are many different tasks to assess WM capacity. In a seminal study, Ecker et al. (2010) found that binding and updating tasks are particularly well suited for assessing WM capacity. Although these tasks are commonly used, it is unclear to what extent the underlying processes are comparable. To investigate the specific and general neurophysiological properties, we designed a task set that allowed us to disentangle and investigate the nature of binding and specific updating processes, namely substitution and transformation.We recruited a heterogeneous sample of 151 participants (female = 89, Mage = 34.77, SD = 12.78) who completed a binding and two updating tasks while an EEG was recorded. Mass univariate cluster-based permutation analyses of event-related potentials revealed a temporally and spatially widespread cluster when comparing binding and updating demands. Within this cluster, there was an increase in positivity associated with the processing of updating demands, which was mainly concentrated in frontal regions in the early time window and later shifted towards parietal regions. When comparing transformation and substitution, we also found an increase in positivity, especially within the traditional P3 time window. Our results point to notable differences in the neurophysiological processes underlying the different WM tasks, while indicating greater similarities for the different updating demands. Further exploration of the neurophysiological mechanisms underlying WM processing could improve our understanding of the essential functions that underlie WM performance.