The Treatment of Depression with Yoga and Walking

重度抑郁症（MDD）影响了多达17%的人口，并在多达40%的个体中没有得到有效治疗。有证据表明，负面情绪与迷走神经张力测量的副交感神经系统（PNS）活动减少有关。瑜伽练习和迷走神经刺激（VNS）都可以通过增加迷走神经张力来增加PNS活动。瑜伽疗法和VNS疗法都被证明可以改善抑郁症和癫痫的症状。磁共振波谱（MRS）显示，重度抑郁症和癫痫患者的脑γ -氨基丁酸（GABA）水平较低，当同一受试者接受药物治疗时，GABA水平升高，症状减轻。通过MRS，我们的研究小组发现，经过60分钟的瑜伽练习后，丘脑GABA水平会上升，而GABA水平的上升与情绪的改善有关。我们的假设是PNS和GABA系统的低活性与抑郁症状有关，瑜伽干预将刺激PNS传入脑干核，从而观察到GABA水平的增加和抑郁症状的减少。在项目开始之前，将进行剂量和可行性研究。目的：1：测量和比较重度抑郁症和非抑郁健康人（ND）在丘脑、脑岛和海马/杏仁核复合体三个解剖结构中的基线GABA水平。2：获取MDD受试者的4张MRS扫描图：基线（扫描1）；经过12周的瑜伽或步行干预（扫描2）；扫描2后，受试者将立即完成60分钟的干预（瑜伽或散步）；然后是扫描3，在扫描2和3（扫描4）后两天再次进行扫描。3：在研究过程中使用心理仪器测量情绪变化，使用呼吸性窦性心律失常（RSA）测量PNS活动。假设：1：在所有roi（即丘脑、脑岛和海马/杏仁核复合体）中，MDD组的基线GABA水平将低于ND组。IIa和IIb：在被分配到瑜伽组的重度抑郁症受试者中，补性GABA水平将在组内发生变化（扫描2-扫描1）。MDD瑜伽组与MDD步行组比较，补益GABA水平在组间存在差异。IIIa和IIIb：重度抑郁症瑜伽组急性GABA水平会有组内变化（Scan 3-Scan 2）。MDD瑜伽组与MDD步行组在急性GABA水平上存在组间差异。IV：恢复的GABA水平没有变化（扫描4 -扫描2）。V & VI: GABA水平与扫描时获得的情绪量表和RSA相关，GABA水平升高与情绪改善、抑郁减少和焦虑减少有关。在干预的过程中，瑜伽组的情绪会比步行组有更大的改善。

Major Depressive Disorder (MDD) affects up to 17% of the population and is not treated effectively in up to 40% of individuals. There is evidence that negative emotions are related to decreased activity in the parasympathetic nervous system (PNS) as measured by vagal tone. Both yoga practices and vagal nerve stimulation (VNS) can increase PNS activity by increasing vagal tone. Both yoga treatments and VNS have been shown to improve symptoms in depression and epilepsy. Using magnetic resonance spectroscopy (MRS), brain gamma-aminobutryic acid (GABA) levels have been shown to be low in subjects with MDD and epilepsy, and when the same subjects are treated with pharmacologic agents, GABA levels increase and symptoms decrease. Using MRS, our group has shown that thalamic GABA levels rise after a 60-minute yoga session and that increases in GABA levels are associated with improved mood. Our hypothesis is that low activity in the PNS and GABA systems is associated with depressive symptoms, and that a yoga intervention will stimulate the PNS afferents to brain stem nuclei, such that associated increases in GABA levels and decreased depressive symptoms will be observed. A dosing and feasibility study will be conducted prior to beginning the project. Aims: 1: To measure and compare baseline GABA levels in MDD and non-depressed healthy subjects (ND) in three anatomic structures, the thalamus, insula and hippocampal/amygdala complex. 2: To obtain four MRS scans in MDD subjects: Baseline (Scan 1); After 12- week yoga or walking interventions (Scan 2); Immediately after Scan 2, subjects will complete a 60-minute intervention (yoga or walking); Followed by Scan 3, and again two days after Scans 2 & 3 (Scan 4). 3: To measure changes in mood using psychological instruments and PNS activity using respiratory sinus arrhythmia (RSA) over the course of the study. Hypotheses: I: Baseline GABA levels will be lower in the MDD group compared to the ND group in all ROIs (i.e., thalamus, insula and hippocampal/amygdala complex). IIa & IIb: There will be a within-group change in tonic GABA levels (Scan 2-Scan 1) in the MDD subjects assigned to the yoga group. There will be a between-group difference in tonic GABA levels when comparing the MDD yoga group with the MDD walking group. IIIa & IIIb: There will be a within-group change in acute GABA levels (Scan 3-Scan 2) in the MDD yoga group. There will be a between-group difference in acute GABA levels when comparing the MDD yoga group with the MDD walking group. IV: There will be no change in recovery GABA levels (Scan 4 - Scan 2). V & VI: GABA levels, mood scales and RSA obtained at the time of scanning will be correlated, such that increasing GABA levels are associated with improved mood, decreased depression and decreased anxiety. VII: There will be a greater improvement in mood over the course of the interventions in the yoga group compared to the walking group.