Effects of tDCS with concurrent cognitive performance targeting the dorsolateral prefrontal cortex and the posterior parietal cortex on EEG microstates in schizophrenia

Objectives: Working memory impairments represent fundamental cognitive deficits in schizophrenia (SZ). Although transcranial direct current stimulation (tDCS) has demonstrated potential in enhancing working memory in SZ, its neural mechanisms and optimized strategies remain to be elucidated. This study explored the effects of tDCS with concurrent cognitive performance targeting the dorsolateral prefrontal cortex (DLPFC) and posterior parietal cortex (PPC) on electroencephalography (EEG) microstates in SZ. Methods: This analysis is based on a randomized, double-blind clinical trial of tDCS with concurrent cognitive performance in SZ. Sixty participants were assigned to three groups: active DLPFC, active PPC, and sham stimulation groups. tDCS was administered concurrently with a visual working memory task. The spatial span test was used to assess working memory at baseline, week 1, and week 2, with resting-state EEG data collected at each time point. Results: No significant differences were detected in the characteristics of the four microstates (A, B, C, and D) at baseline. Compared with the sham stimulation group, the active DLPFC and PPC groups exhibited significant improvements in the duration, occurrence, and coverage of microstate B at week 2. However, the changes in the parameters of microstate B at week 2 were not significantly correlated with working memory improvement. Conclusions: This study suggests that neuromodulation targeting different nodes within the task-induced network may influence the same subnetworks in SZ. This work provides new insights into network-based interventions and contributes to the development of multitarget intervention strategies under task conditions.