title: Executive processes in Parkinson's disease: FDG-PET and network analysis.
abstract: It is assumed widely that the clinical expression of Parkinson's Disease (PD), both motor and cognitive, is subtended by topographically distributed brain networks. However, little is known about the functional neuroanatomy of executive dysfunction in PD. Our objective was to validate further in a PD group the use of network analysis to assess the relationship between executive processes and pathological disorganization of frontostriatal networks. We studied 15 patients with idiopathic PD, and 7 age-matched normal controls, using resting [(18)F]fluorodeoxyglucose (FDG) and high-resolution positron emission tomography (PET). We carried out network analysis on regional metabolic data to identify specific covariation patterns associated with motor and executive dysfunction. We detected two independent patterns relating respectively to the two clinical abnormalities. The first pattern (principal component 1) was topographically similar to that described previously in other PD populations. Subject scores for this pattern discriminated patients from controls and correlated significantly with bradykinesia ratings (P = 0.013, r = 0.655) in PD patients. The second pattern (principal component 2) was characterized by relative ventromedial frontal, hippocampal, and striatal hypometabolism, associated with mediodorsal thalamic hypermetabolism. In the PD group, scores from this pattern correlated with scores on the conditional associative learning (CAL; P = 0.01, r = 0.690) and the Brown Peterson paradigm (BPP; P = 0.017, r = -0.651) tests, respectively assessing strategy and planning, and working memory. According to these findings, the networks subserving bradykinesia and executive dysfunction in PD seems to be topographically distinct and to involve different aspects of subcortico-cortical processing.
authors.affiliation: INSERM U 320, Centre Cyceron, Caen, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Lozza
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Baron
authors.forename: David
authors.initials: D
authors.lastname: Eidelberg
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Mentis
authors.forename: Maren
authors.initials: M
authors.lastname: Carbon
authors.forename: Rose-Marie
authors.initials: RM
authors.lastname: Marié
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D009415:Nerve Net / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D016571:Neural Networks, Computer; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D010300:Parkinson Disease / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D014055:Tomography, Emission-Computed
chemical_list: D019788:Fluorodeoxyglucose F18