This project focuses on clinical translational research into personalized transcranial alternating current stimulation (tACS) for treating anhedonia in late-life depression (LLD). Key components include: (1) Optimizing individualized tACS treatment parameters through randomized, double-blind, controlled trials and establishing precise treatment protocols using deep learning algorithms; (2) Assessing the short-term (2 weeks) and long-term (3 months) efficacy of tACS on depressive symptoms and anhedonia using scales such as the HAMD, SHAPS, and DARS, while monitoring safety; (3) Integrating multimodal detection technologies (64-channel EEG, inflammatory factors/neurotransmitters, etc.) to elucidate the mechanisms by which tACS alleviates anhedonia through modulating prefrontal neural oscillations (y-band), improving synaptic plasticity (increased BDNF), and regulating neurotransmitters (5-HT, DA). This study will establish, for the first time, an individualized parameter system for tACS treatment of LLD, providing a novel non-pharmacological intervention strategy for clinical practice.

This project aims to explore effective treatment strategies and mechanisms of action for personalized transcranial alternating current stimulation (tACS) targeting anhedonia in late-life depression (LLD). Late-life depression has a high prevalence, with 70% of patients exhibiting symptoms of anhedonia, which is

. Current pharmacological treatments face challenges such as poor response rates and significant side effects, creating an urgent need for novel intervention strategies. As a non-invasive neurostimulation technique, tACS can improve depressive symptoms by modulating brain oscillatory activity; however, personalized treatment protocols and mechanisms specifically targeting anhedonia in LLD remain unclear. By optimizing tACS parameters, validating clinical efficacy, and elucidating the underlying neural mechanisms, this project will fill a research gap in this field. The findings will not only provide safe and effective non-pharmacological treatment options for patients with geriatric depression, thereby reducing suicide risk, but will also advance the application of tACS technology in precision medicine for mental disorders, holding significant clinical value and social implications.

Inclusion Criteria:

• (1) Patients were interviewed using the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) - Clinical Version (SCID-5-CV) to confirm that they met the DSM-5 diagnostic criteria for "major depressive disorder"; (2) Age ≥ 60 years; gender not restricted; (3) Hamilton Depression Scale (HAMD)-17 score > 24

Exclusion Criteria:

- (1) History of severe head trauma or serious neurological conditions such as epilepsy; (2) Any brain devices or implants, including cochlear implants and aneurysm clips; treatments such as transcranial direct current stimulation (tDCS).

(3) Individuals who have undergone other physical modulation therapies within the past 8 weeks, including but not limited to non-convulsive electroconvulsive therapy, repetitive transcranial magnetic stimulation, and transcranial direct current stimulation.

Recruitment for this study is currently underway, and we are unable to disclose specific experimental data at this time.