The electrophysiological underpinnings of variation in verbal working memory capacity

Abstract

Working memory (WM) consists of short-term storage and executive components. We studied cortical oscillatory correlates of these two components in a large sample of 156 participants to assess separately the contribution of them to individual differences in WM. The participants were presented with WM tasks of above-average complexity. Some of the tasks required only storage in WM, others required storage and mental manipulations. Our data indicate a close relationship between frontal midline theta, central beta activity and the executive components of WM. The oscillatory counterparts of the executive components were associated with individual differences in verbal WM performance. In contrast, alpha activity was not related to the individual differences. The results demonstrate that executive components of WM, rather than short-term storage capacity, play the decisive role in individual WM capacity limits.

Pupillometry and electroencephalography in the digit span task

“…In an analysis of the absolute spectral power, we observed the typical alpha peak at around 10 Hz at posterior channels, which did not differ between the memory and control condition. Furthermore, confirming expectations from verbal WM EEG literature (Pavlov & Kotchoubey, 2020, in press), we observed an increase in frontal midline theta activity at around 6 Hz in the memory condition compared to the control condition (see Figure 3d). Event-related potentials in response to the verbal material demonstrated clearly visible early N1-P2 components with near zero baseline amplitude (Figure 3c).…”

Temporally distinct oscillatory codes of retention and manipulation of verbal working memory

“…The study is a re-analysis of a previously published dataset (Pavlov & Kotchoubey, 2020). All data supporting conclusions of the study, including raw and preprocessed EEG recordings, are organized in BIDS format and freely available (doi:10.18112/openneuro.ds003565.v1.0.1).…”

“…All data obtained in the study, including raw and preprocessed EEG recordings, are organized in BIDS format and freely available (doi: 10.18112/openneuro.ds003655.v1.0.0). Below, we describe essential methodological aspects but we refer to the original article where the dataset was published first for details (Pavlov & Kotchoubey, 2020).…”

“…Our task and behavioral results are described in detail elsewhere (Pavlov & Kotchoubey, 2020). Briefly, the task used is a modified Sternberg paradigm with temporally distinct encoding and maintenance processing stages (see Figure 1).…”

“…In the current study, we used our previously published dataset (Pavlov & Kotchoubey, 2020) where we recorded EEG in a WM task that engaged the manipulation and retention functions of WM. While in the previous publication we tested hypotheses concerning the relationship between individual differences in WM and brain oscillations, here we performed exploratory analyses of general effects.…”