Modulation of the prefrontal blood oxygenation response to intermittent theta-burst stimulation in depression: A sham-controlled study with functional near-infrared spectroscopy

To better understand the neural mechanisms behind the effect of intermittent theta-burst stimulation (iTBS), we investigated how the prefrontal blood oxygenation response measured by changes in oxygenated haemoglobin (oxy-Hb) was modulated during a sham-controlled iTBS treatment course, and whether this was related to depressive symptom change. In this randomised, double-blind study, patients with ongoing treatment-resistant depression received either active (n = 18) or sham (n = 21) iTBS over the dorsomedial prefrontal cortex for ten to fifteen days with two sessions daily. Event-related functional near-infrared spectroscopy (fNIRS) was measured during each iTBS train, and resting-state oxy-Hb was compared before and after each iTBS session at the first, fifth, and last treatment day. Patients receiving active iTBS had an increase of the event-related oxy-Hb response compared to the sham group on the fifth (bilateral prefrontal cortices p p = .007, right prefrontal p = .025) treatment day. Resting-state analysis showed suppressed oxy-Hb change in active iTBS compared to sham iTBS on the last treatment day (p = .024). Oxy-Hb change was unrelated to depressive symptom change (p = .474). This study describes a modulation of the blood oxygenation response over the prefrontal cortex that was built up during the course of active iTBS treatment in depression.为更好地理解间歇性theta爆发刺激（intermittent theta-burst stimulation, iTBS）效应背后的神经机制，本研究探讨了通过氧合血红蛋白（oxygenated haemoglobin, oxy-Hb）变化测得的前额叶血氧响应在假对照iTBS治疗疗程中的调控模式，以及该响应是否与抑郁症状变化相关。本项随机双盲研究中，正在接受治疗的难治性抑郁症患者被分为两组，分别于背内侧前额叶皮层（dorsomedial prefrontal cortex）接受活性iTBS（n=18）或假iTBS（n=21）治疗，疗程为10至15天，每日开展两次治疗。每次iTBS刺激序列期间均采集事件相关功能近红外光谱（event-related functional near-infrared spectroscopy, fNIRS）数据，并在首次、第5个及末次治疗日的每次iTBS治疗前后，对静息态oxy-Hb水平进行对比。与假治疗组相比，接受活性iTBS的患者在第5个治疗日的事件相关oxy-Hb响应显著升高（双侧前额叶皮层p=0.007，右侧前额叶p=0.025）。静息态分析结果显示，在末次治疗日，活性iTBS组的oxy-Hb变化幅度较假治疗组受到抑制（p=0.024）。oxy-Hb变化与抑郁症状变化无显著关联（p=0.474）。本研究揭示了抑郁症患者在活性iTBS治疗过程中，前额叶皮层血氧响应所产生的动态调控效应。