Publisher: John Wiley & Sons Country of Publication: United States NLM ID: 101570837 Publication Model: Print Cited Medium: Internet ISSN: 2162-3279 (Electronic) NLM ISO Abbreviation: Brain Behav Subsets: MEDLINE

Transcranial Direct Current Stimulation*/methods , Prefrontal Cortex*/physiopathology , Anxiety*/physiopathology , Anxiety*/therapy , Depression*/physiopathology , Depression*/therapy, Humans ; Female ; Male ; Electroencephalography/methods ; Adult ; Cross-Over Studies ; Middle Aged ; Dorsolateral Prefrontal Cortex/physiopathology ; Young Adult

Purpose: Microstate analysis involves examining the temporal dynamics of electroencephalogram (EEG) signals and serves as a crucial method for exploring the neural basis of psychiatric disorders. This study investigates the effects of transcranial direct current stimulation (tDCS) on specific microstate parameter maps-D and C in patients with depression, specifically targeting the dorsomedial prefrontal cortex (DMPFC) and left dorsolateral prefrontal cortex (DLPFC).
Methods: We conducted an open-label, between-subject, crossover trial involving 19 patients clinically diagnosed with depression. A 1 mA electrical current was administered, with anodal stimulation specifically targeting the DMPFC or the left DLPFC. Microstate maps were derived from resting-state EEG recordings obtained prior to and following the application of tDCS. The EEG data were categorized into five distinct microstate classes for subsequent analysis.
Findings: The findings revealed a significant increase in the duration of microstate class D following stimulation in both groups, while microstate class C exhibited no notable changes. Additionally, a significant association was identified between the transition from microstate D to C and alterations in the State-Trait Anxiety Inventory-State (STAI-S) scores after left DLPFC stimulation.
Conclusion: Microstate map D appears to be associated with psychiatric disorders and executive functions, whereas map C may relate to the salience network and mind-wandering. Our findings suggest that microstate maps D and C are responsive to tDCS stimuli, indicating their potential as objective tools for anxiety assessment. Employing transition-focused parameters in EEG microstate analysis may enhance the tracking of rapidly fluctuating emotional states, rather than relying solely on duration metrics. Furthermore, the integration of non-invasive brain stimulation techniques, such as tDCS, with EEG microstate analysis holds significant promise for elucidating the neural mechanisms involved in depression.
Trial Registration: UMIN-CTR Clinical Trial: UMIN000015046.
(© 2025 The Author(s). Brain and Behavior published by Wiley Periodicals LLC.)