Review of the Neural Processes of Working Memory Training: Controlling the Impulse to Throw the Baby Out With the Bathwater

Abstract

Background Smartphone technology has enabled the creation of many working memory training (WMT) Apps, with those peer-reviewed described in a recent review. WMT claims to improve working memory, attention deficits, hyperactivity and fluid intelligence, in line with plasticity brain changes. Critics argue that WMT is unable to achieve “far-transfer”—the attainment of benefits to cognition from one taught context to another dissimilar context—associated with improved quality of life. However, brain changes after a course of WMT in frontoparietal and striatal circuits—that often occur prior to behavioral changes—may be a better indicator of far-transfer efficacy, especially to improve impulse control commonly dysregulated in those with addictive disorders, yet not commonly examined in WMT studies. Method In contrast to previous reviews, the aim here is to focus on the findings of brain imaging WMT training studies across various imaging modalities that use various paradigms, published via PubMed, Scopus, Medline, and Google Scholar. Results 35 brain imaging studies utilized fMRI, structural imaging (MRI, DTI), functional connectivity, EEG, transcranial direct current stimulation (tDCS), cerebral perfusion, and neurogenetic analyses with tasks based on visuospatial and auditory working memory, dual and standard n-back. Discussion Evidence suggests that repeated WMT reduces brain activation in frontoparietal and striatal networks reflective of increased neural circuitry efficiency via myelination and functional connectivity changes. Neural effects of WMT may persist months after training has ended, lead to non-trained task transfer, be strengthened by auxiliary methods such as tDCS and be related to COMT polymorphisms. WMT could be utilized as an effective, non-invasive intervention for working memory deficits to treat impulse and affective control problems in people with addictive disorders.

Maladaptive brain organization at 1 month into abstinence as an indicator for future relapse in patients with alcohol use disorder

“…Abundant literature demonstrates that abstinence from alcohol is commonly associated with structural change and neurocognitive improvements (Meyerhoff & Durazzo, 2020). In substance‐dependent patients gradual neuroplastic change may precede necessary behavioral changes to maintain abstinence and resist relapse (Brooks et al., 2020). Consequently, we hypothesized that those AUD patients whose brains demonstrate greater plastic changes during and after treatment are also more successful in escaping the often‐lifelong cycle of excessive drinking, withdrawal, abstinence, and relapse than those with less prominent neuroplastic changes.…”

Cognitive Training Effectiveness on Memory, Executive Functioning, and Processing Speed in Individuals With Substance Use Disorders: A Systematic Review

“…These results are intriguing and bring up questions about the efficacy of cognitive measures in evaluating potential benefits of WMT, or cognitive training in general, and in adequately assessing "far transfer" effects. In a more recent review study, Brooks et al (2020) reported that WMT can lead to significant neural effects often in the absence of behavioral changes. Moreover, various neuroimaging studies appeared to have found "far transfer" effects of WMT to other un-related cognitive domains, something that might be harder to measure.…”

“…Sala and Gobet (2019) go further and argue that when significant effects are observed, they are often associated with limitations in the design of the experiments, such as the lack of an active control group. However, there is the argument that the longevity or "far-transfer" effects of cognitive training could be being masked by the studies' almost exclusive reliance on primary outcomes, as suggested by Brooks et al (2020) in regards to WMT. These authors also postulate that the current definition of "far-transfer" is too narrow, since it does not consider how cognitive performance (e.g., WM performance) might impact apparently unrelated functions (e.g., impulse control).…”

“…These authors also postulate that the current definition of "far-transfer" is too narrow, since it does not consider how cognitive performance (e.g., WM performance) might impact apparently unrelated functions (e.g., impulse control). In fact, in a review of the neural processes of WMT, Brooks et al (2020), reported that significant neural effects (in frontoparietal and frontostriatal circuitry) could be found, often independently of behavioral changes. Moreover, they reported that alongside neural changes, various neuroimaging studies found "far-transfer" effects of WMT to other un-related cognitive domains.…”

Individual differences in frontoparietal plasticity in humans

“…Short-term training may be a better diagnostic tool for measuring an individual's ability to change in response to practice. Indeed, a few studies have shown that 30-60 minutes of working memory practice is sufficient to cause decreases in FPS activation [42][43][44] , but these studies were too small to investigate individual differences in learning. Another study with a larger sample found that positive functional connectivity within the FPS and in other task-positive systems predicted greater learning from 80-90 minutes of working memory practice 45 .…”