Repetitive Gamma-tACS Improves the Reaction Times of Healthy Young Adults in a Visuospatial Working Memory Task: A Randomized Study

• Published in: Brain sciences Vol. 15; no. 4; p. 343
• Main Authors: Rosato, Miriam, Sala, Marco, Coccaro, Ambra, Cutini, Simone, Liotti, Mario
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27.03.2025; MDPI
• Subjects: Accuracy; Brain research; Delayed response; Entrainment; gamma-band; Memory; Mental task performance; Meta-analysis; neuromodulation; Neurosciences; Older people; Short term memory; Spatial memory; tACS; Teenagers; visuospatial working memory; Young adults; Youth; United States > US; Wisconsin; neuromodulation; tACS; visuospatial working memory; gamma-band
• ISSN: 2076-3425; 2076-3425
• DOI: 10.3390/brainsci15040343

Objective: The aims of the study were to test the short-term and long-term efficacy of repetitive γ-tACS over the left DLPFC to improve visuospatial working memory performance in the spatial capacity delayed response task (SCDRT). Methods: In a single blind placebo-controlled study, 35 healthy young adults were randomly assigned to three sessions of either active γ-tACS (n = 18) or passive sham γ-tACS (n = 17) The design allowed us to evaluate the influence of the stimulation protocol (active vs. sham), the stimulation session number (day 1 to 3), the session block (before stimulation, during stimulation and after stimulation) and the VSWM retention load (1, 3, 5 or 7 stimuli) on the response speed and accuracy. Results: Active γ-tACS selectively improved VSWM performance on day 2 and 3, and the effect was greater following stimulation rather than during stimulation. Significant effects were seen concerning response speed but not accuracy. The VSWM performance gains of the active γ-tACS were no longer present in the long-term at a follow-up session after two weeks. Conclusions: The present study provides novel evidence for a selective improvement in VSWM performance with three repeated sessions of γ-tACS in young adults through the entrainment of gamma rhythms in the left DLPFC.