Mathison Centre for Mental Health Research and Education, University of Calgary, Calgary, AB, Canada; Department of Psychiatry, University of Calgary, Calgary, AB, Canada; Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada.
Department of Psychiatry, University of Calgary, Calgary, AB, Canada; Department of Psychology, Aston University, Birmingham, UK.
J Affect Disord. 2017 Aug 1;217:125-131. doi: 10.1016/j.jad.2017.04.004. Epub 2017 Apr 5.
Major Depressive Disorder (MDD) is highly prevalent and potentially devastating, with widespread aberrations in brain activity. Thalamocortical networks are a potential candidate marker for psychopathology in MDD, but have not yet been thoroughly investigated. Here we examined functional connectivity between major cortical areas and thalamus.
Resting-state fMRI from 54 MDD patients and 40 healthy controls were collected. The cortex was segmented into six regions of interest (ROIs) consisting of frontal, temporal, parietal, and occipital lobes and pre-central and post-central gyri. BOLD signal time courses were extracted from each ROI and correlated with voxels in thalamus, while removing signals from every other ROI.
Our main findings showed that MDD patients had predominantly increased connectivity between medial thalamus and temporal areas, and between medial thalamus and somatosensory areas. Furthermore, a positive correlation was found between thalamo-temporal connectivity and severity of symptoms.
Most of the patients in this study were not medication naïve and therefore we cannot rule out possible long-term effects of antidepressant use on the findings.
The abnormal connectivity between thalamus and temporal, and thalamus and somatosensory regions may represent impaired cortico-thalamo-cortical modulation underlying emotional, and sensory disturbances in MDD. In the context of similar abnormalities in thalamocortical systems across major psychiatric disorders, thalamocortical dysconnectivity could be a reliable transdiagnostic marker.
重度抑郁症（MDD）患病率高且潜在破坏性大，其大脑活动广泛异常。丘脑皮质网络可能是 MDD 精神病理学的潜在候选标志物，但尚未得到彻底研究。在此，我们研究了主要皮质区与丘脑之间的功能连接。
采集了 54 名 MDD 患者和 40 名健康对照者的静息态 fMRI 数据。皮质分为 6 个感兴趣区（ROI），包括额、颞、顶和枕叶以及中央前回和中央后回。从每个 ROI 提取 BOLD 信号时间序列，并与丘脑体素相关联，同时去除其他 ROI 的信号。
我们的主要发现表明，MDD 患者的内侧丘脑与颞叶区之间以及内侧丘脑与躯体感觉区之间的连接普遍增强。此外，发现丘脑-颞叶连接与症状严重程度呈正相关。
本研究中的大多数患者均未服用抗抑郁药，因此我们不能排除抗抑郁药使用对研究结果的可能长期影响。
丘脑与颞叶以及丘脑与躯体感觉区之间的异常连接可能代表了 MDD 中情绪和感觉障碍下皮质-丘脑-皮质调节受损。在主要精神障碍的丘脑皮质系统中存在类似的异常情况下，丘脑皮质连接不良可能是一种可靠的跨诊断标志物。
