Positron Emission Tomography in Transcranial Magnetic Stimulation Intervention for Treatment-resistant Depression

Major depressive disorder (MDD) exhibit reduced visual motor perception, which affects prognosis. Metabolic substance changes and abnormal neural activity in the middle temporal visual area (MT) mediate this perceptual dysfunction. The main questions are: •there is no conclusive evidence of impairment of visual motion suppression in treatment-resistant depression (TRD); •it is unknown that functional abnormalities in the MT of TRD patients mediate possible changes in visual perception •lack of treatment for deficit in visual motor perception; •mechanisms behind the intervention process need to be explored. The goal of this clinical trial is to understand the function of visual motor perception in TRD, to validate the effect of the MT on visual motion perception and to explore the effectiveness of the intervention as well as the neurophysiological mechanisms.

This study was planned to •explore any differences in visual motor perception and function of MT between TRD and healthy controls; •analyze the influence of neurobiological changes in MT and related brain regions on visual motion perception; •investigate the effects of rTMS intervention in MT for treatment of impaired visual perception function in TRD; •studying potential therapeutic mechanisms by PET/MRI imaging.

Participants will divide into TRD group and HC group. Clinical symptoms, scales, visual perception suppression index, PET/MRI, electrophysiology and other clinical data were collected at baseline for both two groups. TRD group received high-frequency rTMS stimulation targeting the MT. Besides, psychological scales, visual suppression index, PET/MRI, electrophysiology and other clinical data were collected during the intervention and after treatment.

The researchers will •compare the differences in visual perceptual function and neurobiological characteristics between the TRD group and the HC group in baseline; •analyze the impact of MT and related brain regions in visual motion perception; •compare the suppression index before and after intervention in TRD to discuss the feasibility of rTMS stimulation targeting the MT to improve visual motion perception abnormalities；•utilize the changes in clinical data of PET/MRI and electrophysiology before and after the treatment of TRD group to explore the possible underlying mechanisms during the treatment process.


Eligibility Criteria:
Inclusion Criteria:

1. Receive two or more adequate doses and courses of antidepressant drugs in different mechanisms that were not effective and had been stable for more than 6 weeks on antidepressant medication prior to enrollment, with non-responsiveness defined as a decrease in HAMD-24 score of \<50%.
2. 24-item Hamilton Depression Scale (HAMD-24) ≥ 20.
3. Normal or corrected to normal vision.
4. Ability to complete spatial suppression psychophysical experiment.
5. education background above the college degree.
6. Age 18-45 years, regardless of gender.
7. Right-handedness.
8. Han Chinese.
9. Signed a written informed consent, willing to participate in the study and be evaluated.

Exclusion Criteria:

1. Co-morbid other mental disorders, including: schizophrenia, mental retardation, substance dependence, etc.
2. Patients with metal objects in the body or with other contraindications to PET-MRI scanning
3. Patients with severe or unstable somatic diseases
4. Women during pregnancy or lactation, and women of childbearing age with positive urine HCG test results during the screening period
5. Benzodiazepines were taken during the experimental period
6. Other conditions that, in the opinion of the investigator, exist that make participation in this clinical trial inappropriate.