A Meta-analysis of Executive Components of Working Memory

Abstract

Working memory (WM) enables the online maintenance and manipulation of information and is central to intelligent cognitive functioning. Much research has investigated executive processes of WM in order to understand the operations that make WM "work." However, there is yet little consensus regarding how executive processes of WM are organized. Here, we used quantitative meta-analysis to summarize data from 36 experiments that examined executive processes of WM. Experiments were categorized into 4 component functions central to WM: protecting WM from external distraction (distractor resistance), preventing irrelevant memories from intruding into WM (intrusion resistance), shifting attention within WM (shifting), and updating the contents of WM (updating). Data were also sorted by content (verbal, spatial, object). Meta-analytic results suggested that rather than dissociating into distinct functions, 2 separate frontal regions were recruited across diverse executive demands. One region was located dorsally in the caudal superior frontal sulcus and was especially sensitive to spatial content. The other was located laterally in the midlateral prefrontal cortex and showed sensitivity to nonspatial content. We propose that dorsal-"where"/ventral-"what" frameworks that have been applied to WM maintenance also apply to executive processes of WM. Hence, WM can largely be simplified to a dual selection model.

Dynamic causal modeling of load-dependent modulation of effective connectivity within the verbal working memory network

“…Recent quantitative meta-analyses have shown that engagement during verbal WM tasks can be seen bilaterally within the DLPFC, PAR and ACC (Wager and Smith, 2003;Nee et al, 2013) although left-sided involvement was more common (Nee et al, 2013). However previous studies (Altamura et al, 2007;Kirschen et al, 2005) as well as the current study suggest that the key driver of lateralisation within the verbal WM network is memory load.…”

“…the total demand on maintenance, updating and manipulation processes) (Braver et al, 1997;Callicott et al, 1999;Owen et al, 1999;Volle et al, 2008) and may be sensitive to content being leftlateralised for verbal and right-lateralised for spatial and object information (Fletcher and Henson, 2001;Wager and Smith, 2003;Nee et al, 2013).…”

Latent Dimensions of Executive Functions in Early Childhood

“…However, it may be the case that each of these abilities are important but for different EF components. For example, working memory has been found in several previous studies to be an important component of EF (Monette et al 2011;Nee et al 2013). Working memory was also found to be important in this study; however, the current study adds to the literature in suggesting the degree of language demands in WM tasks is an important distinguishing quality of EF tasks in preschool children.…”

Working Memory: Maintenance, Updating, and the Realization of Intentions

“…There is some meta-analytic evidence for regional specificity, including interactions between manipulation demand and material type (Wager and Smith 2003). However, a more recent metaanalysis of 36 event-related fMRI studies found only limited support for specificity (Nee et al 2013; see further the updating section below). Instead, it found that four manipulation processes ( protect from external distraction, prevent intrusion of irrelevant memories, shifting of attention, and updating the contents of working memory) engaged several overlapping frontal regions.…”

“…The necessity of a dynamic relation between maintenance and updating has been captured in terms of a "gating mechanism"; a closed gate promotes maintenance, an open gate allows updating. There is evidence from functional imaging that parts of the frontal cortex are more active during working-memory updating relative to other forms of working-memory manipulation, such as inhibition (Dahlin et al 2008) and shifting of attention (Nee et al 2013). However, it has been argued that it is only through interactions with the basal ganglia that the prefrontal cortex realizes this gating function (O'Reilly 2006), such that the striatum provides gating signals to the frontal cortex (Go/update or NoGo/ maintain) via interactions with the thalamus and the substantia nigra.…”