Department of Neurology, Movement Disorders Unit, Hospital de la Santa Creu i Sant Pau Sant Antoni M. Claret 167, Universitat Autònoma de Barcelona, 08025, Barcelona, Spain.
Sant Pau Institute of Biomedical Research (IIB-Sant Pau), Barcelona, Spain.
Brain Imaging Behav. 2017 Oct;11(5):1334-1342. doi: 10.1007/s11682-016-9607-5.
Apathy is a common but poorly understood neuropsychiatric disturbance in Parkinson's disease (PD). In a recent study using event-related brain potentials we demonstrated impaired reward processing and compromised mesocortico-limbic pathways in PD patients with clinical symptoms of apathy. Here we aimed to further investigate the involvement of reward circuits in apathetic PD patients by assessing potential differences in brain structure. Using structural magnetic resonance imaging (MRI) and voxel-based morphometry (VBM) we quantified grey matter volume (GMV) in a sample of 18 non-demented and non-depressed PD patients with apathy, and 18 matched non-apathetic patients. Both groups were equivalent in terms of sociodemographic characteristics, disease stage, cognitive performance and L-Dopa equivalent daily dose. Apathetic patients showed significant GMV loss in cortical and subcortical brain structures. Various clusters of cortical GMV decrease were found in the parietal, lateral prefrontal cortex, and orbitofrontal cortex (OFC). The second largest cluster of GMV loss was located in the left nucleus accumbens (NAcc), a subcortical structure that is a key node of the human reward circuit. Isolated apathy in our sample is explained by the combined GMV loss in regions involved in executive functions, and cortical and subcortical structures of the mesolimbic reward pathway. The correlations observed between apathy and cognition suggests apathy as a marker of more widespread brain degeneration even in a sample of non-demented PD patients.
淡漠是帕金森病（PD）中一种常见但了解甚少的神经精神障碍。在最近一项使用事件相关脑电位的研究中，我们证明了淡漠的 PD 患者存在奖赏处理受损和中脑边缘通路受损。在这里，我们旨在通过评估潜在的大脑结构差异，进一步研究奖赏回路在淡漠型 PD 患者中的参与情况。我们使用结构磁共振成像（MRI）和基于体素的形态测量学（VBM），对 18 名非痴呆和非抑郁的淡漠 PD 患者和 18 名匹配的非淡漠患者的灰质体积（GMV）进行了定量分析。两组在社会人口统计学特征、疾病阶段、认知表现和 L-多巴等效日剂量方面均无差异。淡漠患者在皮质和皮质下脑结构中出现明显的 GMV 损失。在顶叶、外侧前额叶皮质和眶额皮质（OFC）中发现了各种皮质 GMV 减少的簇。GMV 损失的第二大簇位于左侧伏隔核（NAcc），这是一个亚皮质结构，是人类奖赏回路的关键节点。在我们的样本中，孤立的淡漠症可以用涉及执行功能的区域以及中脑边缘奖赏通路的皮质和皮质下结构的 GMV 联合损失来解释。在淡漠症和认知之间观察到的相关性表明，即使在非痴呆 PD 患者的样本中，淡漠症也是更广泛脑退化的标志物。
