title: Set-maintenance and set-shifting problems in schizophrenic subtypes: relationship to dysfunctions of the fronto-striatal loops.
abstract: Research with patients suffering from Parkinson's disease and frontal lobe lesions has shown that disturbances in the fronto-striatal loops in the brain can cause perseveration. Perseveration is a core symptom of schizophrenia, yet the cause is not known. For schizophrenic patients disorders of many parts of the fronto-striatal loops are found, for example disturbances of the prefrontal cortex and the striatum. Perseveration in schizophrenia can be explained with set-maintenance problems, related to dysfunction of the prefrontal cortex, or with set-shifting problems that are related to disorders in the striatum. These set-maintenance and set-shifting problems can be distinguished with neuropsychological tests. Regarding the bloodflow patterns for the different subtypes of schizophrenia three problems are expected as explanations for perseveration: set-maintenance problems concerning abstract information, set-maintenance problems shifting between stimuli and enhanced set-shifting with cues.
authors.affiliation: Afdeling Psychoneurofarmacologie,Katholieke Universiteit Nijmegen.
authors.forename: M G
authors.initials: MG
authors.lastname: Lanser
authors.affiliation: Afdeling Psychoneurofarmacologie,Katholieke Universiteit Nijmegen.
authors.forename: B A
authors.initials: BA
authors.lastname: Ellenbroek
authors.affiliation: Afdeling Psychoneurofarmacologie,Katholieke Universiteit Nijmegen.
authors.forename: A R
authors.initials: AR
authors.lastname: Cools
authors.affiliation: Afdeling Psychiatrie,St. Radboud Ziekenhuis,Nijmegen.
authors.forename: F G
authors.initials: FG
authors.lastname: Zitman