健康与遗传心理学研究室知识库

本研究报告包括两个研究，第一个研究采用结构磁共振成像(structural MRI)技术考察了亚临床抑郁老年人大脑结构的改变，第二个研究则通过任务态功能磁共振成像((task fMRI)技术考察了亚临床抑郁老年人在处理情绪冲突时的大脑活动。

在第一个研究中，通过分析健康老年人和亚临床抑郁老年人的结构像，考察亚临床抑郁老年人大脑的结构，尤其是海马/旁海马结构是否存在异常。该研究以双侧的海马和旁海马作为感兴趣区，结果发现，与健康对照组老年人相比，亚临床抑郁老年人右侧旁海马的灰质体积显著缩小，而且亚临床抑郁老年人双侧旁海马及右侧海马的灰质体积与他们的抑郁得分呈现显著的负相关。这一结果说明海马和旁海马的结构改变和老年抑郁症的发生存在很大的相关。

在第二个研究中，采用词一面孔Stroop任务，通过分析健康老年人和亚临床抑郁老年人在处理情绪冲突时的大脑活动，考察亚临床抑郁老年人的大脑功能是否存在异常。两组老年人的行为成绩不存在显著差异。采用基于全脑的数据分析方法，结果发现，亚临床抑郁老年人处理情绪冲突时，与健康对照组相比，在背外侧前额叶、前扣带、外侧纹状体视觉区、后扣带、楔前叶、顶下小叶等脑区的激活显著增强。此外，在情绪冲突任务中，背外侧前额叶、顶下小叶、外侧纹状体视觉区以及前扣带的大脑信号变化和亚临床抑郁老年人的行为成绩存在显著的正相关。背外侧前额叶、前扣带回等脑区的过度激活反应出亚临床抑郁老年人自上而下的认知控制功能受到损坏。

There are two studies in this research report. By using structural MRI9 the first study explores whether there exist brain structural alternations in old adults with subthreshold depression. The second study employs the task fMRI to examine whether the brain activity of old adults with subthreshold depression dysfunctions in resolving emotional conflict.

In the first study a priori region of interest (ROI) including the bilateral hippocampi and parahippocampi was defined and a voxel-based morphometry analysis was conducted to investigate the structural alterations of the hippocampus/ parahippocampus and potential correlations between its volume and participants' self reported depressive symptoms in the elderly suffering from subthreshold depression. The results showed that elderly people with StD had substantially reduced volumes of the right parahippocampus compared with healthy age-matched controls. Moreover, the volumes of the hippocampus/parahippocampus were significantly correlated with participants' self reported depressive symptoms in StD. These results demonstrate that structural alterations of the hippocampus/parahippocampus may occur at an early stage of depression. Findings of the present study highlighted a relation between structural alterations of the hippocampus/parahippocampus and a precursor of major depression, the subthreshold depression, in older adults.

In the second study, a face-word Stroop task was used to investigate whether the brain activity of the elderly people with StD dysfunctions when resolving emotional conflicts. The behavioral results showed that both emotional and non-emotional distractors generated significant interference conflict in both groups. The old adults with StD did not demonstrate increased distractibility to either type of distractor and performed similarly to the healthy controls in both tasks. Concerning brain activity, the non-emotional task was processed similarly by both groups. however, the differences were striking during the resolution of emotional interference. Data-driven whole-brain analysis demonstrated that in dealing with the emotional interference, old adults with StD shown stronger activity in DLPFC, A.CC, visual extrastriate cortex, and DMN related areas compared with healthy controls. In addition, the incongruent-congruent RT of old adults with StD was significantly correlated with the signal changes of right middle frontal gyrus, right fusiform gyrus, right inferior parietal lobule, and left superior frontal gyrus in the emotional interference task. For healthy controls, the incongruent-congruent RT was significantly correlated with the signal changes of right anterior cingulate and right fusifonn gyrus and the incongruent-congruent accuracy was only correlated with signal changes of right anterior cingulate in the emotional task. These results showed that the brain functions of old adults with StD alters greatly.