title: Impaired executive function signals in motor brain regions in Parkinson's disease.
abstract: Recent evidence has shown that patients with Parkinson's disease (PD) often display deficits in executive functions, such as planning for future behavior, and these deficits may stem from pathologies in prefrontal cortex and basal ganglia circuits that are critical to executive control. Using the antisaccade task (look away from a visual stimulus), we show that when the preparatory 'readiness' to perform a given action is dissociated from the actual execution of that action, PD patients off and on dopamine medication display behavioral impairments and reduced cortical brain activation that cannot be explained by a pathology related to dysfunction in movement execution. Rather, they show that the appropriate task set signals were not in place in motor regions prior to execution, resulting in impairments in the control of subsequent voluntary movement. This is the first fMRI study of antisaccade deficits in Parkinson's disease, and importantly, the findings point to a critical role of the basal ganglia in translating signals related to rule representation (executive) into those governing voluntary motor behavior.
authors.affiliation: Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada.
authors.forename: Ian G M
authors.initials: IG
authors.lastname: Cameron
authors.forename: Giovanna
authors.initials: G
authors.lastname: Pari
authors.forename: Nadia
authors.initials: N
authors.lastname: Alahyane
authors.forename: Donald C
authors.initials: DC
authors.lastname: Brien
authors.forename: Brian C
authors.initials: BC
authors.lastname: Coe
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Stroman
authors.forename: Douglas P
authors.initials: DP
authors.lastname: Munoz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D010300:Parkinson Disease / Q000503:physiopathology*; D012438:Saccades