title: Changes to the lateral geniculate nucleus in Alzheimer's disease but not dementia with Lewy bodies.
abstract: Complex visual hallucinations occur in 70% of dementia with Lewy bodies (DLB) cases and significantly affect patient well-being. Visuo-cortical and retinal abnormalities have been recorded in DLB and may play a role in visual hallucinations. The present study aimed to investigate the lateral geniculate nucleus (LGN), a visual relay centre between the retina and visual cortex, to see if changes to this structure underlie visual hallucinations in DLB.
  
  
  
  Fifty-one [17 probable DLB, 19 control and 15 probable Alzheimer's disease (AD)] cases were recruited for a functional magnetic resonance imaging study, in which patients' response to a flashing checkerboard stimulus was detected and measured in the LGN, before comparison across experimental groups. Additionally, post mortem LGN tissue was acquired for a cross-sectional study using 20 (six DLB, seven control and seven AD) cases and analysed using stereology. α-Synuclein, phosphorylated tau and amyloid-β pathology was also assessed in all cases.
  
  
  
  DLB cases did not significantly differ from controls on neuroimaging, morphometry or pathology. However, a significant increase in amyloid-β pathology, a reduction in number of parvocellular neurones and magnocellular gliosis was found in AD cases compared with control and DLB cases.
  
  
  
  These findings suggest that the early visual system is relatively spared in DLB, which implies that upstream visual structures may be largely responsible for the generation of hallucinatory percepts. The significance of the degeneration of the LGN in AD cases is uncertain.
authors.affiliation: Institute of Neuroscience, Ageing Research Laboratories, Newcastle upon Tyne, UK.|Medical Toxicology Centre, Wolfson Unit of Clinical Pharmacology, Newcastle upon Tyne, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Erskine
authors.affiliation: Institute of Neuroscience, Biomedical Research Building, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: John Paul
authors.initials: JP
authors.lastname: Taylor
authors.affiliation: Institute of Neuroscience, Biomedical Research Building, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Firbank
authors.affiliation: Institute of Neuroscience, Ageing Research Laboratories, Newcastle upon Tyne, UK.
authors.forename: Lina
authors.initials: L
authors.lastname: Patterson
authors.affiliation: Clinical Neurology, Department of Neuroscience and Imaging, Chieti Scalo, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Onofrj
authors.affiliation: Department of Psychiatry, University of Cambridge, Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK.
authors.forename: John T
authors.initials: JT
authors.lastname: O'Brien
authors.affiliation: Institute of Neuroscience, Biomedical Research Building, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Ian G
authors.initials: IG
authors.lastname: McKeith
authors.affiliation: Institute of Neuroscience, Ageing Research Laboratories, Newcastle upon Tyne, UK.
authors.forename: Johannes
authors.initials: J
authors.lastname: Attems
authors.affiliation: Institute of Neuroscience, Biomedical Research Building, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Thomas
authors.affiliation: Institute of Neuroscience, Ageing Research Laboratories, Newcastle upon Tyne, UK.|Medical Toxicology Centre, Wolfson Unit of Clinical Pharmacology, Newcastle upon Tyne, UK.
authors.forename: Chris M
authors.initials: CM
authors.lastname: Morris
authors.affiliation: Institute of Neuroscience, Ageing Research Laboratories, Newcastle upon Tyne, UK.
authors.forename: Ahmad Adam
authors.initials: AA
authors.lastname: Khundakar
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology* / Q000503:physiopathology*; D001931:Brain Mapping; D003430:Cross-Sectional Studies; D005260:Female; D005829:Geniculate Bodies / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D020961:Lewy Body Disease / Q000473:pathology* / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D010775:Photic Stimulation
keywords: dementia with Lewy bodies; fMRI; lateral geniculate nucleus; neuropathology; stereology