基于脚桥核神经网络的帕金森病冻结步态的机制探讨

Alterations of pedunculopontine nucleus pathway in Parkinson’s disease patients with freezing of gait

目的探讨脚桥核(PPN)神经网络在帕金森病(PD)冻结步态(FOG)中的作用及其变化规律。方法对16例PD伴冻结步态(PD FOG+)患者,17例PD不伴冻结步态(PD FOG-)患者及17名正常对照者,行静息态功能MRI(rs-fMRI)扫描,并用功能连接方法对结果进行分析;同时行DTI检查,对脑白质纤维DTI的各相关参数进行组间比较。结果与正常对照组及PD FOG-组相比,PD FOG+组与PPN功能连接异常的脑区主要分布在皮质-脑桥核-小脑通路以及视觉相关颞叶皮质;与正常对照组相比,PD FOG+组存在明显的脑白质结构异常改变,包括连接两侧大脑半球的胼胝体、连接皮质-皮质间的白质纤维束、连接皮质-皮质下结构的白质纤维束以及连接丘脑的白质纤维束。结论 PD FOG+患者存在异常的PPN功能连接网络,主要影响皮质-脑桥核-小脑通路和参与视觉信息处理的颞叶相关皮质,并有显著的脑白质结构异常改变,可涉及运动、感觉和认知传导相关通路。如结合rs-fMRI和DTI技术,可以进一步提高对PD FOG潜在发病机制的认识。

Objective To study the role of the pedunculopontine nucleus(PPN) pathway in patients with Parkinson’s disease(PD)with freezing of gait(FOG)(PD FOG+) compared with those without freezing(PD FOG-) and healthy controls(HCs). Methods Resting state functional MRI(rs-fMRI) and DTI scans were obtained from 16 PD FOG+ parents, 17 PD FOG-patients and 17 HCs. Between-group difference in PPN functional connectivity(FC) was performed to assess FC dysfunction. Tract-based spatial statistics(TBSS) was applied to compare white matter(WM) impairment across the whole brain between groups. Results Compared with HCs and with PD FOG-, PD FOG+ patients exhibited abnormal PPN FC, mainly in the corticopontine-cerebellar pathways as well as the visual temporal areas. Compared with HCs, PD FOG+ patients showed more pronounced WM abnormalities, including the interhemispheric connections of corpus callosum, the cortico-cortical WM tracts, the corticofugal tract as well as tracts connecting the thalamus.Conclusions FOG in PD is associated with abnormal PPN FC network, mainly affecting the corticopontine-cerebellar pathways as well as visual temporal areas involved in visual processing, and with diffuse WM deficits extending to motor, sensory and cognitive regions. Combining rs-fMRI and DTI method, our study should advance the understanding of neural mechanisms underlying FOG in PD.