Brain and Mind Research Programme, Central European Institute of Technology, CEITEC MU, Masaryk University, Brno, Czech Republic.
Brain and Mind Research Programme, Central European Institute of Technology, CEITEC MU, Masaryk University, Brno, Czech Republic; First Department of Neurology, School of Medicine, Masaryk University and St. Anne's Hospital, Brno, Czech Republic.
Neuropsychologia. 2017 Nov;106:236-244. doi: 10.1016/j.neuropsychologia.2017.09.034. Epub 2017 Sep 30.
We used a functional MRI paradigm involving conventional vs. unconventional views of objects to assess bottom-up vs. top-down visual processing in Parkinson's disease (PD) with normal cognition, PD with mild cognitive impairment (MCI), and MCI due to Alzheimer's disease (AD) as compared to healthy controls. We particularly aimed at determining whether the task discriminated between PD with and without MCI and between two MCI groups due to distinct pathologies (AD and PD).
116 right-handed subjects (21 MCI due to AD; 16 PD with normal cognition; 24 PD with MCI; 55 healthy controls) performed a visual object-matching task in a T MR scanner. T statistic maps were computed to contrast task-based activation during unconventional vs. conventional view conditions. One-way ANOVAs and post hoc tests were performed to assess differences across and between groups.
Both MCI groups performed worse than controls in the unconventional views condition and showed reduced activation of right anterior cingulate cortex and right superior parietal lobule (PD with MCI), and right middle and inferior frontal gyri (MCI due to AD). Neural responses in cortical areas within the ventral and dorsal visual pathway appeared to be preserved in both MCI groups. Receiver operating characteristic analysis of MRI contrast in the right superior parietal lobule distinguished PD with and without MCI with 87.50% sensitivity and 86.98% specificity.
Impaired recognition of objects presented in unconventional orientations in MCI due to PD and AD was associated with decreased activation of frontoparietal regions, consistent with defective top-down regulation of visual processing. Aberrant activation of superior parietal cortex may serve as an early imaging biomarker of impending cognitive impairment in PD.
我们使用了一种涉及物体常规和非常规视图的功能磁共振成像范式，来评估认知正常的帕金森病（PD）、轻度认知障碍（MCI）的 PD 以及阿尔茨海默病（AD）所致 MCI 患者的自上而下的视觉加工与自下而上的视觉加工，与健康对照组进行比较。我们特别旨在确定该任务是否可以区分 PD 伴或不伴 MCI，以及由于不同病理（AD 和 PD）导致的两个 MCI 组之间的区别。
116 名右利手受试者（21 名 AD 所致 MCI；16 名认知正常的 PD；24 名 MCI 的 PD；55 名健康对照）在 T 磁共振扫描仪中进行了视觉物体匹配任务。计算 T 统计量图以对比非常规视图与常规视图条件下的任务激活。进行单因素方差分析和事后检验以评估组间和组内的差异。
两个 MCI 组在非常规视图条件下的表现均不如对照组差，并且显示出右前扣带皮层和右顶上小叶（MCI 的 PD）以及右中、下回额回（AD 所致 MCI）的激活减少。两个 MCI 组的腹侧和背侧视觉通路的皮质区域的神经反应似乎都得到了保留。右顶上小叶磁共振成像对比的受试者工作特征分析能够以 87.50％的敏感性和 86.98％的特异性区分 PD 伴和不伴 MCI。
PD 和 AD 所致 MCI 患者对非常规方向呈现的物体识别受损与额顶叶区域的激活减少有关，这与视觉处理的自上而下调节缺陷一致。顶叶上皮质的异常激活可能是 PD 认知障碍的早期影像学生物标志物。
