| Summary: | 碩士 === 國立陽明大學 === 生物醫學資訊研究所 === 103 === Background: Theta-burst stimulation (TBS) appears to be a promising treatment alternative for depression. However, little is known about the underlying mechanism of its neuromodulation effect on emotion pathway for major depression. The aim of this study is to investigate the effect of neuromodulation on brain responses to emotional prosody in patients with treatment-resistant major depression by two-week TBS treatment using magnetoencephalography (MEG).
Materials and Methods: Fourteen patients with treatment-resistant major depressive disorder (trMDD) and ten healthy control subjects (HC) were recruited. Brain responses of each participant were recorded using a whole-head MEG system (Vectorview, Elekta Neuromag, Helsinki, Finland) while passively listening to emotional prosody (happy, sad, angry and neutral verbal tones). Each patient underwent clinical assessments and MEG experiments before (baseline) and after TBS treatment (week 1 and week 2). Each HC subject participated in the MEG experiment once. For each emotional prosody category, the beamforming method was applied to obtain spatiotemporal images of brain responses in a voxel-wise manner. Brain emotional response index (BERI) was then estimated at two time components (M50: 30-80 ms; M100: 80-120 ms). Nonparametric statistical analysis of BERI maps among three weeks as well as correlation analyses between baseline BERI and depressive severity were performed.
Results: We found changes of neuronal activity in trMDD patients by two-week TBS-treatment. Short-term and reversible plasticity of brain responses were found in the regions of the left anterior and posterior insular, caudate nucleus, left inferior frontal gyrus and anterior/middle cingulate cortex. There were positive correlation between the percent improvement of the HDRS-17 scores and the change of BERI in the left superior frontal gyrus nearby DLPFC which was the target of TBS. Furthermore, our results suggested lower activity in the right precuneus and STG before TBS treatment could predict better antidepressant treatment response in trMDD patients.
Conclusion: Our results demonstrated dynamic changes of neuronal processing in emotion perception and reversible plasticity of brain responses by two-week TBS-intervention in patients with trMDD, which provides a neuroimaging evidence of short-term neuromodulation on the time scale of weeks by TBS.
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