Enhanced working-memory performance by cross-frequency coupled transcranial alternative current stimulation
Byoung-Kyong Min1,2, Kyung Mook Choi3, Hyun-Seok Kim3, Min-Hee Ahn3; 1Department of Brain and Cognitive Engineering, Korea University, Seoul 02841, Korea, 2McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA, 3Institute for Brain and Cognitive Engineering, Korea University, Seoul 02841, Korea
Transcranial current stimulation is a potent neuromodulation technique used to enhance human cognitive functions in a non-invasive manner. In this study, we investigated whether a cross-frequency coupled transcranial alternative current (CFC-tAC) stimulation improved working-memory performance. Sixteen participants were recruited for a tAC-treated group, and sixteen age-sex-matched controls also participated in this study as a sham group. They were instructed to perform a modified Sternberg task, where a combination of letters and digits was presented in a 3-different workload condition (3, 5, and 7 items to be encoded) before and after the tAC or sham stimulation. The stimulation group was treated by a CFC-tAC stimulation for 20 mins (input channel: F3, return channels: Fp1, Fz, F7, and C3). We analyzed the behavioral data using a repeated-measures ANOVA. We observed a significant decrease in reaction times (F(1,7) = 13.495, p < 0.01; pre-tAC: 940.63 ms, post-tAC: 796.74 ms) and a significant increase in the accuracy of task performance (F(1,7) = 6.102, p < 0.05; pre-tAC: 76.99%, post-tAC: 86.49%) in the tAC-treated participants, particularly in a most difficult task condition (i.e., 7-workload). Our observations are indicative of a feasibility to enhance cognitive performance of normal participants by the CFC-tAC non-invasive stimulation.
Topic Area: EXECUTIVE PROCESSES: Working memory