title: Hallucinations and conscious access to visual inputs in Parkinson's disease.
abstract: The pathophysiology of visual hallucinations in Parkinson's disease has yet to be characterized. Although stimulus-driven ("bottom-up") processes are known to be impaired, the role of "top-down" processes remains to be determined. Distinguishing between conscious and non-conscious detections (i.e. access to consciousness) may be a valuable way of monitoring top-down processes. Conscious access to visual inputs was investigated to identify the neural substrates underlying susceptibility to hallucinations in Parkinson's disease. Seventeen healthy controls, 18 Parkinson's disease patients with minor visual hallucinations and 16 without were enrolled in the study. During functional magnetic resonance imaging, the participants performed a visual detection task. The detection threshold was significantly higher in each patient group than in healthy controls while the two groups of patients did not differ significantly. Compared with hallucination-free patients, patients with minor hallucinations displayed hyperactivation of prefrontal and right occipital cortices, and hypoactivation of the left cingulate, temporal and occipital cortices. During conscious access to visual inputs, the functional network in patients with visual hallucinations differed from that seen in patients without visual hallucinations. This suggests that the supremacy of top-down processes in visual information processing may enhance susceptibility to hallucinations in Parkinson's disease.
authors.affiliation: Univ. Lille, CNRS, UMR 9193 - SCALab - Sciences Cognitives et Sciences Affectives, F-59000 Lille, France.|CHU Lille, Clinique de Psychiatrie, CURE, F-59000 Lille, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Lefebvre
authors.affiliation: Department of Neurology and Movement Disorders, Lille University Medical Center, F-59000 Lille, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Baille
authors.affiliation: Univ. Lille, CNRS, UMR 9193 - SCALab - Sciences Cognitives et Sciences Affectives, F-59000 Lille, France.|CHU Lille, Clinique de Psychiatrie, CURE, F-59000 Lille, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: Jardri
authors.affiliation: Univ. Lille, Inserm, U1171 - Degenerative &vascular cognitive disorders, F-59000 Lille, France.
authors.forename: Lucie
authors.initials: L
authors.lastname: Plomhause
authors.affiliation: Univ. Lille, CNRS, UMR 9193 - SCALab - Sciences Cognitives et Sciences Affectives, F-59000 Lille, France.|CHU Lille, Clinique de Psychiatrie, CURE, F-59000 Lille, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Szaffarczyk
authors.affiliation: Department of Neurology and Movement Disorders, Lille University Medical Center, F-59000 Lille, France.|Univ. Lille, Inserm, U1171 - Degenerative &vascular cognitive disorders, F-59000 Lille, France.
authors.forename: Luc
authors.initials: L
authors.lastname: Defebvre
authors.affiliation: Univ. Lille, CNRS, UMR 9193 - SCALab - Sciences Cognitives et Sciences Affectives, F-59000 Lille, France.|CHU Lille, Clinique de Psychiatrie, CURE, F-59000 Lille, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Thomas
authors.affiliation: Univ. Lille, Inserm, U1171 - Degenerative &vascular cognitive disorders, F-59000 Lille, France.|Neuroimaging Department, Lille University Medical Center, F-59000 Lille, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Delmaire
authors.affiliation: Univ. Lille, CNRS, UMR 9193 - SCALab - Sciences Cognitives et Sciences Affectives, F-59000 Lille, France.|CHU Lille, Clinique de Psychiatrie, CURE, F-59000 Lille, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Pins
authors.affiliation: Department of Neurology and Movement Disorders, Lille University Medical Center, F-59000 Lille, France.|Univ. Lille, Inserm, U1171 - Degenerative &vascular cognitive disorders, F-59000 Lille, France.
authors.forename: Kathy
authors.initials: K
authors.lastname: Dujardin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002540:Cerebral Cortex / Q000503:physiopathology*; D003243:Consciousness; D005260:Female; D006212:Hallucinations / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology*; D014796:Visual Perception