Transfer of training from one working memory task to another: behavioural and neural evidence

Abstract

N-back working memory (WM) tasks necessitate the maintenance and updating of dynamic rehearsal sets during performance. The delayed matching-to-sample (dMTS) task is another WM task, which in turn involves the encoding, maintenance, and retrieval of stimulus representations in sequential order. Because both n-back and dMTS engage WM function, we hypothesized that compared to a control task not taxing WM, training on the n-back task would be associated with better performance on dMTS by virtue of training a shared mental capacity. We tested this hypothesis by randomly assigning subjects (N = 43) to train on either the n-back (including 2-back and 3-back levels) or an active control task. Following training, dMTS was administered in the fMRI scanner. The n-back group performed marginally better than the active control group on dMTS. In addition, although the n-back group improved more on the less difficult 2-back level than the more difficult 3-back level across training sessions, it was improvement on the 3-back level that accounted for 21% of the variance in dMTS performance. For the control group, improvement in training across sessions was unrelated to dMTS performance. At the neural level, greater activation in the left inferior frontal gyrus, right posterior parietal cortex, and the cerebellum distinguished the n-back group from the control group in the maintenance phase of dMTS. Degree of improvement on the 3-back level across training sessions was correlated with activation in right lateral prefrontal and motor cortices in the maintenance phase of dMTS. Our results suggest that although n-back training is more likely to improve performance in easier blocks, it is improvement in more difficult blocks that is predictive of performance on a target task drawing on WM. In addition, the extent to which training on a task can transfer to another task is likely due to the engagement of shared cognitive capacities and underlying neural substrates—in this case WM.

Working memory training mostly engages general-purpose large-scale networks for learning

“…Also the contemporary models of WM suggest that neither maintaining nor manipulating information in mind involve specialized brain networks, but these functions rather take place in brain networks also contributing to basic processes of goal-directed attention (Eriksson et al 2015). As activation changes in these networks are proportional to improvement of WM task performance (Olesen et al 2004, Beatty et al 2015, Garner & Dux 2015, Salminen et al 2016, these networks appear to significantly contribute to the process of learning cognitive tasks.…”

N-back Versus Complex Span Working Memory Training

“…Another study by Kundu, Sutterer, Emrich, and Postle (2013) used EEG and TMS to demonstrate that transfer following WM training was supported by changes in task-related effective connectivity in frontoparietal and parieto-occipital networks that were engaged by the training and transfer tasks. While very few studies have examined changes in EEG measures due to training, there is a small body of work using fMRI that also suggests that training is associated with functional changes that have been localized to posterior parietal and prefrontal cortices (Beatty et al, 2015; Buschkuehl, Hernandez-Garcia, Jaeggi, Bernard, & Jonides, 2014; Salminen, Kuhn, Frensch, & Schubert, 2016; for an fNIRS study see, McKendrick et al 2014; Schneiders et al, 2011; Thompson, Waskom, & Gabrieli, 2016; Vartanian et al, 2013). While our results are consistent with this notion of fronto-parietal involvement in dual n-back training effects, it is worth noting that our frontal alpha results are present in slightly more anterior clusters of electrodes than are typically seen.…”

Evidence for the contribution of COMT gene Val158/108Met polymorphism (rs4680) to working memory training‐related prefrontal plasticity

“…Working memory, an ability to maintain and manipulate information for a short period of time (Miyake & Shah, ), has been reported to be trainable (Danielsson, Zottarel, Palmqvist, & Lanfranchi, ). However, only a limited number of studies have explored the neural mechanism for working memory training effect (Beatty et al, ; Dahlin, Neely, Larsson, Bäckman, & Nyberg, ; Schweizer, Grahn, Hampshire, Mobbs, & Dalgleish, ). As far as memory span training is concerned, there are fewer studies and the results are contradictory.…”