van den Heuvel Odile A, Veltman Dick J, Groenewegen Henk J, Dolan Raymond J, Cath Danielle C, Boellaard Ronald, Mesina Catalina T, van Balkom Anton J L M, van Oppen Patricia, Witter Menno P, Lammertsma Adriaan A, van Dyck Richard
Department of Psychiatry, VU University Medical Center and GGZ Buitenamstel, Valeriusplein 9, 1075 BG Amsterdam, The Netherlands.
Psychiatry Res. 2004 Dec 30;132(3):225-37. doi: 10.1016/j.pscychresns.2004.06.007.
Previous imaging studies of obsessive-compulsive symptom states have implicated frontal-striatal and limbic regions in the pathophysiology of obsessive-compulsive disorder (OCD). Functional imaging studies, however, have yielded inconsistent results, presumably due to methodological differences (patient inclusion criteria, stimulus paradigm, imaging technique, and absence of control groups). In the present study, randomized presentation of contamination-related and neutral visual stimuli was used to investigate the neurophysiological correlates of contamination fear in a group of medication-free OCD patients with washing behaviors and healthy controls. A total of 21 subjects (11 OCD patients and 10 healthy controls) were scanned using H(2)(15)O positron emission tomography (PET). Subjects were presented with pictures of clean and dirty surroundings and were requested to make indoor/outdoor decisions to control for attention differences. State anxiety and obsessionality were rated after each scan using visual analogue scales. Main effects of stimulus type (contamination vs. neutral) were found in bilateral occipital cortex in both groups. A significant group interaction effect was observed in the left amygdala reflecting enhanced activity in response to contamination stimuli in OCD patients. Sensitization effects were observed in the right amygdala in the OCD group; these paralleled an increase in levels of distress and obsessionality as well as a decrease in dorsolateral prefrontal activity. The findings of the present study are consistent with the hypothesis of decreased frontal-striatal control of limbic structures, specifically the amygdala, resulting in an inadequate fear response in OCD patients with contamination fear.
以往对强迫症状状态的影像学研究表明，额叶纹状体和边缘系统区域与强迫症（OCD）的病理生理学有关。然而，功能影像学研究结果并不一致，推测是由于方法学上的差异（患者纳入标准、刺激范式、成像技术以及缺乏对照组）。在本研究中，采用随机呈现与污染相关和中性的视觉刺激，来调查一组有洗涤行为的未服药OCD患者和健康对照中污染恐惧的神经生理学相关性。共有21名受试者（11名OCD患者和10名健康对照）接受了H(2)(15)O正电子发射断层扫描（PET）。向受试者呈现干净和肮脏环境的图片，并要求他们做出室内/室外的判断，以控制注意力差异。每次扫描后使用视觉模拟量表对状态焦虑和强迫观念进行评分。在两组的双侧枕叶皮层均发现了刺激类型（污染与中性）的主效应。在左侧杏仁核观察到显著的组间交互效应，反映出OCD患者对污染刺激的反应增强。在OCD组的右侧杏仁核观察到致敏效应；这些效应与痛苦和强迫观念水平的增加以及背外侧前额叶活动的减少平行。本研究结果与以下假设一致，即额叶纹状体对边缘结构，特别是杏仁核的控制减弱，导致有污染恐惧的OCD患者恐惧反应不足。
