Cognitive Enhancement of Numerical and Arithmetic Capabilities: a Mini-Review of Available Transcranial Electric Stimulation Studies

Abstract

Arithmetic capabilities are complex cognitive skills essential for handling requirements of the modern world. At the same time, educational institutions are challenged with mathrelated problems, e.g., developmental dyscalculia and math anxiety, and also with less severe difficulties of arithmetic understanding. Thus, non-invasive techniques for cognitive enhancement have attracted researchers' and practitioners' interest in the fields of education, psychology, and neuroscience. Particularly, studies employing transcranial electric stimulation (tES) in arithmetic learning, problem solving, and performance in numerical tasks and operations have shaped an optimistic perspective of cognitive enhancement in these domains, building on the fronto-parietal correlates of healthy and deficient arithmetic performance and learning. However, the heterogeneity of stimulation approaches in numerical cognition researchwith different electrode montages, stimulation protocols, tasks, outcomes, and combinations thereof-may also showcase a variety of parameters relevant more generally to the cognitive domain. Here, we present a short overview of the different tES approaches to enhance numerical and arithmetic capabilities in performance and training within the general framework of cognitive enhancement. We conclude that performance and training gains can be obtained from different strategical tES configurations, but more standardization, better translation between neurodevelopmental perspectives and tES principles, as well as pre-registered and controlled studies in critical populations are needed.

Switching between Multiple Codes of SNARC-Like Associations: Two Conceptual Replication Attempts with Anodal tDCS in Sham-Controlled Cross-Over Design

“…Several interesting tDCS parameters have not been explored with the present cognitive effects (see Schroeder et al, 2017a , for a review of different tDCS parameters in stimulation studies). It is currently unknown whether changes in intensity or electrode configuration (such as a bilateral vs. extracephalic return electrode configuration) would lead to comparable stimulation outcomes.…”

Effects of Anodal tDCS on Arithmetic Performance and Electrophysiological Activity

“…Further support for this distinction comes from a training study, showing an increase in theta band ERS and a decrease in lower alpha band ERD with increasing use of fact retrieval over procedural calculation in complex arithmetic problems (Grabner and De Smedt, 2012). Against this background, these regions discussed above have been the targets of most transcranial electrical stimulation (tES) studies on arithmetic performance (for a review, see Schroeder et al, 2017), and theta and alpha band ERS/ERD patterns have been used to investigate physiological stimulation effects (Rütsche et al, 2015).…”

Reduction of implicit cognitive bias with cathodal tDCS to the left prefrontal cortex

“…In fact, negative or unexpected stimulation results in cognitive performance may be linked to the claims that tDCS was generally ineffective (Horvath, Forte, & Carter, 2015) or at least that some configurations produce smaller effects than others in the cognitive domain (Jacobson, Koslowsky, & Lavidor, 2012). Alternatively, it may be possible that another tDCS configuration could be more effective, especially seeing the variety of possible protocols (e.g., Schroeder, Dresler, et al, 2017). Counterintuitively, but in line with above neuroimaging results, it may be even possible that left prefrontal networks were also involved in the activation of implicit…”