The Neural Mechanisms Of The Effects Of Temporal Interference Stimulation On Spatial Working Memory

Background: Temporal Interference(TI)stimulation is an emerging transcranial electrical stimulation technique,which retains the advantages of non-invasivemethods,and theoretically can focus on deep brain regions,providing a new method and direction for non-invasive neuromodulation techniques in future research and application.The effectiveness of TI stimulation has been initially verified in animal studies and few human functional studies.In order to further explore the effectiveness of TI stimulation in modulating human cognitive functions,this experiment combined with functional magnetic resonance imaging technology to investigate the effect of TI stimulation on working memory performance and its neural mechanisms.Methods: The experiment was a 2(stimulus type: active stimulus,sham stimulus)× 2(measurement time: pre-test,post-test)× 2(memory load: low load,high load)within-subjects design.25 subjects received two(active and sham)TI stimuli.Before and after each stimulation,they received two functional magnetic resonance imaging sequence scans and completed a change detection task at the same time.The effectiveness and feasibility of TI stimulation on working memory modulation was assessed by ANOVA on the accuracy and reaction time of working memory tasks before and after stimulation as well as brain imaging data.Results: In low memory load,there was no significant difference in accuracy before and after active and sham stimuli,and a significant decrease in reaction time in both active and sham stimulus posttests.In high memory load,the reaction time in active stimulus posttests was significantly lower than in pretests,and in sham stimuli,there was no significant difference in reaction time in pretests and posttests.Significant decreases in activation of the left inferior frontal gyrus were found in all three phases of the working memory interaction.Simple effects analysis showed that activat ion was significantly decreased in bilateral prefrontal and parieto-occipital brain regions in the active stimulus posttest compared to the pretest,and in the left middle frontal gyrus and inferior frontal gyrus compared to the sham stimulus posttest.Conclusion: TI stimulation increased the response speed of visuospatial working memory with high memory load.In all three phases of working memory,brain areas with significantly decreased activation were found in the active stimulusposttest,and TI stimulation could effectively modulate the level of neural activity in high memory load visuospatial working memory to some extent.