title: Resting-state frontostriatal functional connectivity in Parkinson's disease-related apathy.
abstract: One of the most common neuropsychiatric symptoms in Parkinson's disease (PD) is apathy, affecting between 23% and 70% of patients and thought to be related to frontostriatal dopamine deficits. In the current study, we assessed functional resting-state frontostriatal connectivity and structural changes associated with the presence of apathy in a large sample of PD subjects and healthy controls, while controlling for the presence of comorbid depression and cognitive decline. Thirty-one healthy controls (HC) and 62 age-, sex-, and education-matched PD patients underwent resting-state functional magnetic resonance imaging (MRI). Apathy symptoms were evaluated with the Apathy Scale (AS). The 11 Beck Depression Inventory-II items that measure dysphoric mood symptoms as well as relevant neuropsychological scores were used as nuisance factors in connectivity analyses. Voxel-wise analyses of functional connectivity between frontal lobes (limbic, executive, rostral motor, and caudal motor regions), striata (limbic, executive, sensorimotor regions), and thalami were performed. Subcortical volumetry/shape analysis and fronto-subcortical voxel-based morphometry were performed to assess associated structural changes. Twenty-five PD patients were classified as apathetic (AS > 13). Apathetic PD patients showed functional connectivity reductions compared with HC and with non-apathetic patients, mainly in left-sided circuits, and predominantly involving limbic striatal and frontal territories. Similarly, severity of apathy negatively correlated with connectivity in these circuits. No significant effects were found in structural analyses. Our results indicate that the presence of apathy in PD is associated with functional connectivity reductions in frontostriatal circuits, predominating in the left hemisphere and mainly involving its limbic components.
authors.affiliation: Departament de Psiquiatria i Psicobiologia Clínica, Universitat de Barcelona. Barcelona, Catalonia, Spain.
authors.forename: Hugo Cesar
authors.initials: HC
authors.lastname: Baggio
authors.forename: Bàrbara
authors.initials: B
authors.lastname: Segura
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Garrido-Millan
authors.forename: Maria-José
authors.initials: MJ
authors.lastname: Marti
authors.forename: Yaroslau
authors.initials: Y
authors.lastname: Compta
authors.forename: Francesc
authors.initials: F
authors.lastname: Valldeoriola
authors.forename: Eduardo
authors.initials: E
authors.lastname: Tolosa
authors.forename: Carme
authors.initials: C
authors.lastname: Junque
mesh_terms: D000368:Aged; D057565:Apathy; D003342:Corpus Striatum / Q000098:blood supply*; D005260:Female; D005625:Frontal Lobe / Q000098:blood supply*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000098:blood supply* / Q000502:physiology; D010100:Oxygen / Q000097:blood; D010300:Parkinson Disease / Q000473:pathology* / Q000503:physiopathology; D012146:Rest; D066127:White Matter / Q000473:pathology
chemical_list: D010100:Oxygen
keywords: Parkinson's disease; apathy; functional imaging; resting-state connectivity