Nailin Yao1, Shirley Pang2, Charlton Cheung3, Richard Shek-Kwan Chang2, Kui Kai Lau2, John Suckling4, Kevin Yu1, Henry Ka-Fung Mak5, Grainne McAlonan6, Shu-Leong Ho7, Siew-Eng Chua3. 1. Department of Psychiatry, Queen Mary Hospital, The University of Hong Kong, Pokfulam, Hong Kong. 2. Division of Neurology, Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong. 3. Department of Psychiatry, Queen Mary Hospital, The University of Hong Kong, Pokfulam, Hong Kong; State Key Laboratory for Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong. 4. Department of Psychiatry and Behavioural and Clinical Neuroscience Institute, University of Cambridge, United Kingdom & Cambridge and Peterborough Foundation NHS Trust, UK. 5. Department of Diagnostic Radiology, The University of Hong Kong, Pokfulam, Hong Kong. 6. Department of Psychiatry, Queen Mary Hospital, The University of Hong Kong, Pokfulam, Hong Kong; State Key Laboratory for Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong; Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, King's College London, London SE5 8AZ, UK. Electronic address: grainne.mcalonan@kcl.ac.uk. 7. Division of Neurology, Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong. Electronic address: slho@hku.hk.
Abstract
BACKGROUND: Visual hallucinations are an important non-motor complication of Parkinson's disease (PD) and carry a negative prognosis. Their biological basis is uncertain, but may relate to the activity of resting state networks in brain. We therefore aimed to investigate functional activity of brain in patients with visual hallucinations (PDVH) in resting state compared to patients without hallucinations (PDnonVH) and a healthy control group (HC). METHODS: Resting state functional MRI was acquired and the primary analysis compared the amplitude of low-frequency fluctuations (ALFF) across groups. This informed a secondary analysis, in the PD groups only, comparing functional connectivity between a 'seed' region in the occipital lobe and the rest of the brain. RESULTS: Individuals with PDVH showed lower ALFF in bilateral lingual gyrus and cuneus and greater ALFF in temporo-parietal regions, medial temporal gyrus and cerebellum than PDnonVH and HC. PDnonVH also had lower ALFF in occipitoparietal region and greater ALFF in medial temporal gyrus, temporo-parietal and cerebellum regions than HC. Functional connectivity analysis revealed that, although both PD groups had lower occipital functional connectivity relative to the HC group, occipital - corticostriatal connectivity was significantly higher in those with PDVH compared with PDnonVH. CONCLUSION: Our study reveals widespread hemodynamic alterations in PD. However, within a functionally abnormal occipital lobe, those with PDVH have even lower ALFF than non-hallucinators, but have higher occipital functional connectivity with cortical-striatal regions. These findings suggest disruption of pathways underpinning both primary visual perceptual and intrinsic visual integration may contribute to visual hallucinations in PD.
BACKGROUND:Visual hallucinations are an important non-motor complication of Parkinson's disease (PD) and carry a negative prognosis. Their biological basis is uncertain, but may relate to the activity of resting state networks in brain. We therefore aimed to investigate functional activity of brain in patients with visual hallucinations (PDVH) in resting state compared to patients without hallucinations (PDnonVH) and a healthy control group (HC). METHODS: Resting state functional MRI was acquired and the primary analysis compared the amplitude of low-frequency fluctuations (ALFF) across groups. This informed a secondary analysis, in the PD groups only, comparing functional connectivity between a 'seed' region in the occipital lobe and the rest of the brain. RESULTS: Individuals with PDVH showed lower ALFF in bilateral lingual gyrus and cuneus and greater ALFF in temporo-parietal regions, medial temporal gyrus and cerebellum than PDnonVH and HC. PDnonVH also had lower ALFF in occipitoparietal region and greater ALFF in medial temporal gyrus, temporo-parietal and cerebellum regions than HC. Functional connectivity analysis revealed that, although both PD groups had lower occipital functional connectivity relative to the HC group, occipital - corticostriatal connectivity was significantly higher in those with PDVH compared with PDnonVH. CONCLUSION: Our study reveals widespread hemodynamic alterations in PD. However, within a functionally abnormal occipital lobe, those with PDVH have even lower ALFF than non-hallucinators, but have higher occipital functional connectivity with cortical-striatal regions. These findings suggest disruption of pathways underpinning both primary visual perceptual and intrinsic visual integration may contribute to visual hallucinations in PD.
Authors: Joseph Classen; Jiri Koschel; Christian Oehlwein; Klaus Seppi; Peter Urban; Christian Winkler; Ullrich Wüllner; Alexander Storch Journal: J Neural Transm (Vienna) Date: 2017-07-12 Impact factor: 3.575
Authors: Stephanie M Hare; Judith M Ford; Aral Ahmadi; Eswar Damaraju; Aysenil Belger; Juan Bustillo; Hyo Jong Lee; Daniel H Mathalon; Bryon A Mueller; Adrian Preda; Theo G M van Erp; Steven G Potkin; Vince D Calhoun; Jessica A Turner Journal: Schizophr Bull Date: 2017-03-01 Impact factor: 9.306