title: Attention and visual dysfunction in Parkinson's disease.
abstract: Visual processing extends from the retinal level to the ventral temporal lobe, and is modified by top-down and bottom-up processing. Complex visual hallucinations (VH) are commonly a feature of disorders which affect temporal lobe structures, frequently in association with impairment of ascending monoaminergic pathways. When Parkinson's disease (PD) is associated with VH, pathological changes characteristically affect the temporal lobes, a finding which is recapitulated by imaging findings. However, a major association of VH is with cognitive decline, and this is typically linked to deficits in attention and working memory, both of which are modulated by dopamine. Similarly, dopamine plays a crucial role in the function of prefrontal cortex, in addition to controlling access to consciousness via gating mechanisms that are dependent on the basal ganglia.
authors.affiliation: Division of Neurology, Department of Medicine, Faculty of Health Sciences, University of Stellenbosch, PO Box 19063, Tygerberg 7505, Cape Town, South Africa.
authors.forename: Hugo
authors.initials: H
authors.lastname: Botha
authors.forename: Jonathan
authors.initials: J
authors.lastname: Carr
mesh_terms: D001288:Attention; D003072:Cognition Disorders / Q000150:complications / Q000503:physiopathology; D004298:Dopamine / Q000502:physiology*; D006212:Hallucinations / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D008570:Memory, Short-Term; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology*; D013702:Temporal Lobe / Q000503:physiopathology; D014796:Visual Perception / Q000502:physiology*
chemical_list: D004298:Dopamine