Klinisch-neuropsychologische und funktionell-bildgebende Korrelate exekutiver Funktionen unter besonderer Berücksichtigung der Inhibitionskontrolle bei Parkinson-Patienten

The predominance of executive dysfunctions in patients with Parkinson`s disease (PD) was frequently and consistently reported by neuropsychological and functional brain imaging studies. These disturbances are caused by pathophysiological changes in the dopaminergic system and related circuits linking subcortical and cortical regions, also affecting other neurotransmitter systems. The purpose of this project was the investigation of the neuropsychological profile of PD patients on one hand. On the other hand, neural correlates of interference control as one component of executive functions in healthy controls (young and old) and PD patients were studied using functional magnetic resonance imaging (fMRI) on a spatial stimulus-response compatibility task (Simon effect). Neuropsychologically, PD patients showed slowing in simple motor speed and deficits in measures of executive functioning. Using functional imaging and comparing neuronal patterns of activation during active inhibition, older subjects showed strong bilateral fronto-parietal cortical activations. Successful inhibition in PD patients was associated with focused activations in inferior frontal cortex, insular cortex and the cerebellum. Our findings in PD are discussed in terms of underlying pathophysiological changes, affecting normal functioning of brain networks.