title: Default-mode network connectivity in cognitively unimpaired drug-naïve patients with rigidity-dominant Parkinson's disease.
abstract: Parkinson's disease (PD) with akinetic rigidity (PDAR) is more likely to develop cognitive deficits compared to PD with tremor-dominant symptoms (PDTD). The default mode network (DMN) is highly relevant for cognitive processes, so this study tested the functional connectivity (FC) of DMN in cognitively unimpaired PDARpatients. Resting-state fMRI data were collected in 21 cognitively unimpaired early stage drug-naïve patients with PDARand 21 healthy controls (HC). PD patients were matched closely to HCs for demographic and cognitive variables. FC of DMN was evaluated by seed-based correlation approach. Compared to HCs, despite comparable cognitive performance and no statistically discernible GM volume differences, a disruption in the DMN of PDARsubjects was detected. A decreased FC of DMN was found, specifically prominent in the posterior DMN. We also found a significantly increased FC of the anterior DMN. Three parts of left medial prefrontal regions (anterior, ventral, and dorsal) had significantly increased FC with the cerebellum. In addition, increased FC values of the anterior and ventral parts were negatively correlated with cognitive scores. An evident decline of FC of posterior DMN and enhanced compensatory FC of anterior DMN suggested an early functional disruption of DMN in PDARprior to clinical evidence of cognitive impairment. It could be hypothesized that the dysfunction of DMN connectivity may have a role in the development of cognitive decline in PD. However, further longitudinal studies are warranted to understand the underlying neural mechanisms and their relevance to clinical and cognitive outcomes in PDARsubtype.
authors.affiliation: Department of Neurology, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Yanbing
authors.initials: Y
authors.lastname: Hou
authors.affiliation: Department of Neurology, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Luo
authors.affiliation: Department of Neurology, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Neurology, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Ruwei
authors.initials: R
authors.lastname: Ou
authors.affiliation: Department of Neurology, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Wanglin
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Neurology, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Song
authors.affiliation: Department of Radiology, Huaxi MR Research Center (HMRRC), West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Qiyong
authors.initials: Q
authors.lastname: Gong
authors.affiliation: Department of Neurology, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China. hfshang2002@126.com.
authors.forename: Huifang
authors.initials: H
authors.lastname: Shang
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009127:Muscle Rigidity / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000523:psychology; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000503:physiopathology; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000523:psychology; D012146:Rest
keywords: Cognition; Functional connectivity; Parkinson’s disease; Resting-state fMRI; Subtype