晚发性抑郁症患者抑制控制的功能磁共振研究

Inhibitory control dysfunction of late-onset depression：an event-related fMRI study

目的 应用功能磁共振成像技术探讨晚发性抑郁症患者抑制控制加工过程的神经环路.方法 14例晚发性抑郁症患者（首次发病年龄≥60岁）和13名年龄、性别、受教育程度相匹配的健康老年人（对照组）,采用视觉Go/Nogo试验范式进行fMRI扫描,要求被试对正立的三角形尽快准确地按键（Go）,对倒立的三角形不按键（Nogo）,比较两组被试在Go、Nogo两种不同任务下脑区激活的差异.结果 （1）晚发性抑郁症患者在Go任务下反应时间、正确率与对照组相比,差异无显著性（P＞0.05）.Nogo任务下的误按率晚发性抑郁症患者[（0.09±0.06）]高于对照组[（0.04±0.02）],差异有显著性（P＜0.05）.（2）在Go任务下,晚发性抑郁症患者较对照组激活增强的脑区有左中央后回、左顶下小叶、右中央前回、左中央旁小叶、右顶下小叶、右前扣带回、左额中回、右额中回、右额上回.在Nogo任务下,晚发性抑郁症患者较对照组激活增强的脑区有左顶下小叶、左额中回.结论 晚发性抑郁症患者抑制控制功能障碍与前额叶-纹状体环路损害有关,其中双侧额中回、右前扣带回过度激活可能是其神经基础.

Objective To investigate the neural circuit of inhibitory control in late-onset depressed patients（LOD） by functional magnetic resonance imaging（fMRI）. Methods Fourteen late-onset depressed patients （LOD group） and thirteen elderly healthy subjects（ control group） were recruited. The two groups were age, gender, and education matched. All the subjects performed a visual Go/Nogo task during the fMRI scan. Erect or inverted isosceles triangular figures were used for stimuli. The two groups were instructed to press a button as quickly and correctly as possible when the erect triangular figures（Go） were presented, but not to response when the inverted triangular figures（Nogo） were presented. The differences of brain activation between the two groups were compared. Results （ 1 ） During Go trials, there were no significant differences in reaction time and hit rate between the two groups （P 〉 0.05 ）. During Nogo trials, however, the late-onset depressed patients showed much higher false alarm rate（0.09 ±0.06） compared with control group（0.04 ±0.02） （P〈0.05=. （2） During Go trials , LOD group showed significantly greater activity in left postcentral gyrus, left inferior parietal lobule, right precentral gyrus, left paracentral lobule, right inferior parietal lobule, right anterior cingulate cortex, left middle frontal gyrus, right middle frontal gyrus, right superior frontal gyrus compared with the control group. Whereas during Nogo trials, LOD group exhibited greater activity in left inferior parietal lobule and left middle frontal gyrus compared with the control group. Conclusion This study suggests that inhibitory control dysfunction in late-onset depressed patients may be closely related to frontostriatal circuit impairment. Over activation in left middle frontal gyrus, right middle frontal gyrus and right anterior cingulate cortex may contribute to the pathogenesis of late-onset depression.