Shine James M, Halliday Glenda M, Gilat Moran, Matar Elie, Bolitho Samuel J, Carlos Maria, Naismith Sharon L, Lewis Simon J G
Parkinson's Disease Research Clinic, Brain and Mind Research Institute, The University of Sydney, New South Wales, Australia.
Hum Brain Mapp. 2014 May;35(5):2206-19. doi: 10.1002/hbm.22321. Epub 2013 Jun 13.
Visual misperceptions and hallucinations represent a problematic symptom of Parkinson's disease. The pathophysiological mechanisms underlying these symptoms remain poorly understood, however, a recent hypothesis has suggested that visual misperceptions and hallucinations may arise from disrupted processing across attentional networks. To test the specific predictions of this hypothesis, 22 patients with Parkinson's disease underwent 3T fMRI while performing the Bistable Percept Paradigm, a task that has previously been shown to identify patients with hallucinations. Subjects are required to study a battery of randomly assigned "monostable" and "bistable" monochromatic images for the presence or absence of a bistable percept. Those patients who scored a high percentage of misperceptions and missed images on the task were less able to activate frontal and parietal hubs of the putative Dorsal Attention Network. Furthermore, poor performance on the task was significantly correlated with the degree of decreased activation in a number of these hubs. At the group level, the difference between processing a bistable versus a monostable cue was associated with increased recruitment of the anterior insula. In addition, those patients with impaired performance on the paradigm displayed decreased resting state functional connectivity between hubs of the Ventral and Dorsal Attention Networks. These same patients had significantly decreased gray matter in the insula bilaterally. In addition, a combined analysis of the separate neuroimaging approaches revealed significant relationships across the impaired networks. These findings are consistent with specific predictions from a recently proposed hypothesis that implicates dysfunction within attentional networks in Parkinsonian hallucinations.
视觉错觉和幻觉是帕金森病的一个棘手症状。然而，这些症状背后的病理生理机制仍知之甚少，最近有一个假说认为，视觉错觉和幻觉可能源于注意力网络处理过程的中断。为了检验这一假说的具体预测，22名帕金森病患者在进行双稳态知觉范式任务时接受了3T功能磁共振成像检查，该任务此前已被证明可识别出有幻觉的患者。受试者需要研究一系列随机分配的“单稳态”和“双稳态”单色图像，以判断是否存在双稳态知觉。那些在该任务中出现高比例错觉和漏看图像的患者，激活假定背侧注意力网络的额叶和顶叶枢纽的能力较弱。此外，该任务表现不佳与这些枢纽中一些枢纽激活程度的降低显著相关。在组水平上，处理双稳态线索与单稳态线索之间的差异与前岛叶的募集增加有关。此外，在该范式中表现受损的患者，腹侧和背侧注意力网络枢纽之间的静息态功能连接性降低。这些患者双侧岛叶的灰质也显著减少。此外，对单独的神经影像学方法进行综合分析，揭示了受损网络之间的显著关系。这些发现与最近提出的一个假说的具体预测一致，该假说认为帕金森病幻觉与注意力网络功能障碍有关。
