DataSheet1_Abnormal activation patterns in MT+ during visual motion perception in major depressive disorder.docx

ObjectivePrevious studies have found that patients with Major Depressive Disorder (MDD) exhibit impaired visual motion perception capabilities, and multi-level abnormalities in the human middle temporal complex (MT+), a key brain area for processing visual motion information. However, the brain activity pattern of MDD patients during the perception of visual motion information is currently unclear. In order to study the effect of depression on the activity and functional connectivity (FC) of MT+ during the perception of visual motion information, we conducted a study combining task-state fMRI and psychophysical paradigm to compare MDD patients and healthy control (HC).
MethodsDuration threshold was examined through a visual motion perception psychophysical experiment. In addition, a classic block-design grating motion task was utilized for fMRI scanning of 24 MDD patients and 25 HC. The grating moved randomly in one of eight directions. We examined the neural activation under visual stimulation conditions compared to the baseline and FC.
ResultsCompared to HC group, MDD patients exhibited increased duration threshold. During the task, MDD patients showed decreased beta value and percent signal change in left and right MT+. In the sample comprising MDD and HC, there was a significant negative correlation between beta value in right MT+ and duration threshold. And in MDD group, activation in MT+ were significantly correlated with retardation score. Notably, no such differences in activation were observed in primary visual cortex (V1). Furthermore, when left MT+ served as the seed region, compared to the HC, MDD group showed increased FC with right calcarine fissure and surrounding cortex and decreased FC with left precuneus.
ConclusionOverall, the findings of this study highlight that the visual motion perception function impairment in MDD patients relates to abnormal activation patterns in MT+, and task-related activity are significantly connected to the retardation symptoms of the disease. This not only provides insights into the potential neurobiological mechanisms behind visual motion perception disorder in MDD patients from the aspect of task-related brain activity, but also supports the importance of MT+ as a candidate biomarker region for MDD.

研究背景与目的：既往研究表明，重度抑郁症（Major Depressive Disorder, MDD）患者存在视觉运动感知能力受损，且在负责加工视觉运动信息的关键脑区——人类颞中回复合体（human middle temporal complex, MT+）中存在多层面异常。但目前学界尚未明确MDD患者在感知视觉运动信息时的脑活动模式。为探究抑郁症对视觉运动感知过程中MT+的活动与功能连接（functional connectivity, FC）的影响，本研究结合任务态功能磁共振成像（task-state fMRI）与心理物理学范式，对MDD患者与健康对照（healthy control, HC）开展对比研究。方法：本研究通过视觉运动感知心理物理学实验检测时长阈值。此外，采用经典区组设计光栅运动任务，对24名MDD患者与25名健康对照进行fMRI扫描。实验中光栅将沿8个预设方向中的某一个随机运动。本研究分析了视觉刺激条件相较于基线条件下的神经激活水平与功能连接。结果：与健康对照组相比，MDD患者的时长阈值显著升高。任务态扫描期间，MDD患者左右侧MT+的β值（beta value）与信号变化百分比（percent signal change）均出现下降。在全部入组样本（MDD患者与健康对照）中，右侧MT+的β值与时长阈值呈显著负相关；而在MDD组内，MT+的激活程度与精神运动迟滞评分（retardation score）显著相关。值得注意的是，初级视觉皮层（primary visual cortex, V1）未观察到此类激活差异。进一步以左侧MT+作为种子区开展功能连接分析时，相较于健康对照组，MDD组右侧距状裂及其周围皮层（calcarine fissure and surrounding cortex）的功能连接增强，而左侧楔前叶（precuneus）的功能连接减弱。结论：本研究结果整体显示，MDD患者的视觉运动感知功能受损与MT+的异常激活模式密切相关，且任务相关脑活动与该病的精神运动迟滞症状显著关联。本研究从任务相关脑活动的视角，为揭示MDD患者视觉运动感知障碍背后潜在的神经生物学机制提供了新的理论依据，同时也支持MT+可作为MDD的候选生物标志物脑区。