title: Dysfunctions of cerebral networks precede recognition memory deficits in early Parkinson's disease.
abstract: We aimed to investigate changes in the verbal recognition memory network in patients with early Parkinson's disease (PD) without overt recognition memory alteration. Verbal recognition memory was assessed in 24 PD patients in early stages of the disease and a control group of 24 healthy subjects during fMRI data acquisition. Participants were presented with a list of 35 words before imaging, and later during fMRI scanning they were required to recognize these previously presented words. Both model-based (FEAT) and model-free (MELODIC) analyses of the fMRI data were carried out with FSL software. Memory was also assessed by means of Rey's Auditory Verbal Learning Test (RAVLT). PD patients showed no difference in the fMRI recognition memory task and recognition memory assessed by the RAVLT compared to healthy controls. Model-based analysis did not show significant differences between groups. On the other hand, model-free analysis identified components that fitted the task-model and were common to all the participants, as well as components that differed between PD and healthy controls. PD patients showed decreased task-related activations in areas involved in the recognition memory network and decreased task-related deactivations in the default mode network in comparison with controls. In conclusion, model-free fMRI analysis detected alterations in functional cerebral networks involved in a verbal memory task in PD patients without evident recognition memory deficit.
authors.affiliation: Servicio de Neurología, Centro de Investigación en Red de Enfermedades Neurodegenerativas (CIBERNED), Hospital Clínic, Universidad de Barcelona, Spain.
authors.forename: Naroa
authors.initials: N
authors.lastname: Ibarretxe-Bilbao
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Zarei
authors.forename: Carme
authors.initials: C
authors.lastname: Junque
authors.forename: Maria Jose
authors.initials: MJ
authors.lastname: Marti
authors.forename: Barbara
authors.initials: B
authors.lastname: Segura
authors.forename: Pere
authors.initials: P
authors.lastname: Vendrell
authors.forename: Francesc
authors.initials: F
authors.lastname: Valldeoriola
authors.forename: Nuria
authors.initials: N
authors.lastname: Bargallo
authors.forename: Eduardo
authors.initials: E
authors.lastname: Tolosa
mesh_terms: D000328:Adult; D000368:Aged; D002540:Cerebral Cortex / Q000503:physiopathology*; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D008875:Middle Aged; D009434:Neural Pathways / Q000503:physiopathology*; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D021641:Recognition, Psychology / Q000502:physiology