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Free keywords:
Memory; Cognitive control; Inhibition; Transcranial Direct Current Stimulation; Retrieval-induced forgetting; Stop-signal task
Abstract:
Across two experiments, we sought to investigate the necessity of the right Prefrontal Cortex in successful control over interfering memories during se-lective retrieval, as indexed by the retrieval-induced forgetting effect (RIF), and the relationship between this ability and efficient motor stopping. To this end, we recruited 53 (experiment 1) and 72 (experiment 2) healthy volun-teers, which were randomly assigned to three groups that received either an-odal, cathodal, or sham trascranial Direct Current Stimulation (tDCS) to the right Inferior Frontal Gyrus while performing a standard retrieval-practice paradigm with category-exemplars word pairs, which is typically employed to induce RIF. In experiment 2 participants also performed a stop-signal task (SST) during tDCS. We analyzed memory performance data by fitting logis-tic mixed effects models in R, with item type, stimulation group, and the pos-sible interaction term as fixed effects, and subject and category as random intercept terms, in order to account for both subject- and item-related var-iability. In both experiments, RIF was impaired under real tDCS compared to sham tDCS, but only for a subset of the stimulus categories. In addition to that, we did not find neither effects of tDCS on motor stopping perfor-mance in the SST, nor a relationship between motor stopping and memory control abilities. Overall, our results support the notion that tDCS over the right Prefrontal Cortex can alter memory control performance as indexed by RIF. However, further studies are needed in order to clarify the factors that moderate the effects of tDCS on RIF across different stimulus categories
