Impaired visuospatial transformation but intact sequence processing in Parkinson disease

We examined whether visuospatial deficits in Parkinson disease (PD) can be explained by a domain-general, The authors examined whether visuospatial deficits in Parkinson's disease (PD) can be explained by a domain–general, nonspatial impairment in the sequencing or serial chaining of mental operations. They argue that visuospatial deficits in PD result from impairments to spatial transformation routines involved in the computation of mappings between spatial locations. These routines are mediated by dopaminergic pathways linking the basal ganglia, prefrontal cortex, supplementary motor area, and parietal cortex.