Response inhibition subprocesses and dopaminergic pathways: basal ganglia disease effects.

Response inhibition is a component of executive functions, which can be divided into distinct subprocesses by means of event-related potentials (ERPs). These subprocesses are (pre)-motor inhibition and inhibition monitoring, which are probably reflected by the Nogo-N2 and Nogo-P3, respectively. Here we ask, if these subprocesses may depend on distinct basal ganglia subsystems.

Response monitoring in de novo patients with Parkinson's disease.

Background: Parkinson's disease (PD) is accompanied by dysfunctions in a variety of cognitive processes. One of these is error processing, which depends upon phasic decreases of medial prefrontal dopaminergic activity. Until now, there is no study evaluating these processes in newly diagnosed, untreated patients with PD ("de novo PD").

Effects of aging, Parkinson's disease, and dopaminergic medication on response selection and control.

We examined effects of short-term and long-term dopaminergic medication in Parkinson's disease on conflict monitoring or response selection processes. These processes were examined using event-related potentials (ERPs), while subjects performed a stimulus-response (S-R) compatibility task. An extended sample of young and elderly controls, Parkinson's disease patients with a medication history (PDs) and initially diagnosed, drug-naïve de novo PD patients (de novo PDs) were enrolled.

Effects of stimulus-response compatibility on inhibitory processes in Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative basal ganglia disorder accompanied by deficits in cognitive functions. One important executive function is the inhibition of responses. Due to basal ganglia damage, processes related to the selection of response are also dysfunctional.

Feedback-related processes during a time-production task in young and older adults.

Objective: We examined whether the age-related decline in the integrity of the mid-brain dopamine system plays a role in the adaptation of precisely timed motor responses by feedback information.

Methods: Participants performed a time-production task with feedback given after each trial. They were encouraged to use the feedback for improving temporal response accuracy.

Time estimation in healthy ageing and neurodegenerative basal ganglia disorders.

A decline in motor performance and timing performance is evident not only in clinical patient groups, e.g. with Parkinson's or Huntington's disease but also in normal ageing.

Central and parietal event-related lateralizations in a flanker task.

Recently Wascher et al. (1999) reported that in a flanker task with arrow stimuli not only the known lateralized readiness potential (LRP) that reflects lateralized response activation was induced, but also a parietal lateralized activation (direction encoding lateralization; DEL) that was interpreted as reflecting an earlier coding of a response side. However, the Wascher study did not exclude that the DEL could have also been due to lateralized stimulus- or attention-related factors.