Examining the efficacy of combined tDCS and cognitive training on memory consolidation.

Poster Session F - Tuesday, April 16, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Domenico Tullo¹ (d.tullo@northeastern.edu), Yan Ge², Ariel Guicheng Tan³, Quynh Theresa Do⁴, Alexandru D. Iordan⁵, John Jonides⁵, Susanne M. Jaeggi^1,4; ¹Northeastern University, ²King’s College London, ³Harvard University, ⁴University of California-Irvine, ⁵University of Michigan

Transcranial direct current stimulation (tDCS) serves as a non-invasive brain stimulation method, which has shown promise for enhancing learning and memory by applying tDCS to the left prefrontal cortex during working memory and word learning exercises. We recruited 62 healthy older adults (Mage = 72.67; SDage = 4.79; 65% Female) for a 5-session word learning intervention, using a between-subjects, sham-controlled pretest-posttest design with a 3-month follow-up. Participants memorized different word lists each session while receiving active or sham tDCS over the left prefrontal cortex, and were later tested on recall 25 minutes post-stimulation. In subsequent sessions, post-test, and follow-up, cumulative recall of all learned words was assessed, alongside a recognition task. The results demonstrated improved word recognition in the group receiving tDCS at post-test and at 3 month follow-up. Moreover, the results replicated previous work in demonstrating improved word recall after training; however, the degree of improvement was less pronounced as compared to previous work. In the post-test fMRI scans, bold activation was significantly higher in the left dorsolateral prefrontal cortex for participants who received active tDCS treatment compared to the sham group, which may indicate better consolidated memories; however, this increased activity did not persist at 3-month follow-up. The results from this study will inform the design of interventions to mitigate age-related memory decline and also further our understanding of the mechanisms underlying electrical stimulation and brain plasticity.

Topic Area: EXECUTIVE PROCESSES: Development &aging