Effects of Repetitive Transcranial Magnetic Stimulation Treatment on Emotion Regulation in Major Depression: a MEG Study

• Main Authors: Mei-Ying Wu, 吳美瑛
• Other Authors: Li-Fen Chen
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/66729950240709874882

碩士 === 國立陽明大學 === 腦科學研究所 === 101 === Background: Major depressive disorder (MDD) is characterized by emotion dysregulation and cognitive impairments. High-frequency repetitive transcranial magnetic stimulation (rTMS) that has been proposed could improve depressive symptoms as well as cognitive function in depression. However, the neural mechanism of rTMS on cognitive-emotional interactions is still unclear. The current study aimed to investigate effects of rTMS on the interaction between emotion regulation and cognitive functions in MDD patients. We also aimed to evaluate predictive value of neuroimaging data under a flanker-emotional go/nogo task so as to guide subsequent rTMS sessions. We hypothesized that rTMS decreased the neural activity in the dorsal anterior cingulate cortex (dACC) during inhibitory control to negative stimuli in depression. Materials and methods: Twenty-nine medication-resistant patients with MDD (22 females, aged 27-63 years) were applied 10-session high-frequency rTMS over the left dorsolateral prefrontal cortex (DLPFC) for consecutive 2 weeks. Event-related magnetic field (ERMF) were measured as patients performed a flanker-emotional go/nogo task that required the inhibitory controls to emotional stimuli pre-treatment, after 5th, and 10th rTMS treatment sessions. Twenty-five gender- and age-matched healthy subjects were recruited as controls. The magnetoencephalographic (MEG) recordings were using a 306-channel whole head neuromagnetometer. Clinical response to rTMS was defined as a decrease of 50% or more in the 17-item Hamilton Rating Scale for depression (HDRS) score from baseline to the end of treatment. To estimate the dynamic changes of neuronal activity, noise-free MEG data were underwent a source reconstruction using the beamformer-based source imaging technique. The time components related to the task were selected (80 ms, 120 ms, 180 ms, and 280 ms). Image data were analyzed using mixed design ANOVAs (i.e., flexible factorial model in SPM8). Pearson correlation analysis was performed to assess the relation between treatment outcome, behavior changes, and cortical activity. Results: Seventeen out of 29 MDD patients (59%) were treatment responders after 2-week rTMS therapy. The behavioral results showed that MDD patients, particularly the non-responders, produced more false alarm than controls. A trend rTMS treatment effect was found in the non-responder. The key findings of this study indicate that, lower baseline left dPFC activity involving inhibitory control in nogo trials at 280 ms was positively correlated with false alarm and negatively correlated with depression improvement. Beside, decreased activity in the right dACC to negative stimuli in nogo trials at 280 ms from baseline to the end of treatment was found in the responder, which reflected emotional bias toward negative stimuli modulated by rTMS. Discussion: We demonstrated that rTMS modulated the mood-congruent bias that decreased the inhibitory resources to sad stimuli in the responder. The results suggested that rTMS ameliorated the emotional bias to negative stimuli in the responders. Repetitive TMS produced effects at the stimulated cortical regions but also at distant connected sites, which in line with previous studies. Repetitive TMS treatment may modulate the neuronal activity in the prefrontal cortex, which through frontal-cingulate trans-synaptic connections in depression. Moreover, the left dPFC in inhibitory control may predict response for rTMS treatment in medication-resistant depression. Conclusions: These findings provided neuroimaging evidence of brain plasticity increasing our understanding of HF-rTMS treatment effects on emotion regulation in patients of major depressive disorder.