Effects of transcranial direct current stimulation on spatial memory based on a spatial matching task

Memory decline (MD) has become a critical issue affecting personal life and societal function, especially spatial memory plays a central role in daily life. Transcranial direct current stimulation (tDCS) has been demonstrated as an efficient neural modulation for memory, however its effects on spatial memory and underlying mechanism remain unclear. This study proposes a spatial matching paradigm with a 2-back principle to explore the enhancement of the tDCS on spatial memory. Three conditions of pre-tDCS, short-tDCS, and long-tDCS accompanied with event-related potential, brain network and behavioral data are applied to investigate the effect. Results show that the tDCS enhances the P300 components in prefrontal and parietal regions, with significantly higher amplitudes and shorter latencies than pre-tDCS. The brain network connectivity also increases as well as the subjects respond more accurately and quickly. Moreover, females exhibit greater changes in P3 amplitude and mean potential area than males, suggesting higher sensitivity to the tDCS. These findings indicate that the tDCS could enhance memory by increasing cortical excitability and neural efficiency and this study provides valuable insights into the neural mechanisms behind the enhanced memory function of the tDCS and introduces a novel framework for its evaluation.