title: Role of basal ganglia circuits in resisting interference by distracters: a swLORETA study.
abstract: BACKGROUND
  The selection of task-relevant information requires both the focalization of attention on the task and resistance to interference from irrelevant stimuli. Both mechanisms rely on a dorsal frontoparietal network, while focalization additionally involves a ventral frontoparietal network. The role of subcortical structures in attention is less clear, despite the fact that the striatum interacts significantly with the frontal cortex via frontostriatal loops. One means of investigating the basal ganglia's contributions to attention is to examine the features of P300 components (i.e. amplitude, latency, and generators) in patients with basal ganglia damage (such as in Parkinson's disease (PD), in which attention is often impaired). Three-stimulus oddball paradigms can be used to study distracter-elicited and target-elicited P300 subcomponents.
  
  
  RESULTS
  In order to compare distracter- and target-elicited P300 components, high-density (128-channel) electroencephalograms were recorded during a three-stimulus visual oddball paradigm in 15 patients with early PD and 15 matched healthy controls. For each subject, the P300 sources were localized using standardized weighted low-resolution electromagnetic tomography (swLORETA). Comparative analyses (one-sample and two-sample t-tests) were performed using SPM5® software. The swLORETA analyses showed that PD patients displayed fewer dorsolateral prefrontal (DLPF) distracter-P300 generators but no significant differences in target-elicited P300 sources; this suggests dysfunction of the DLPF cortex when the executive frontostriatal loop is disrupted by basal ganglia damage.
  
  
  CONCLUSIONS
  Our results suggest that the cortical attention frontoparietal networks (mainly the dorsal one) are modulated by the basal ganglia. Disruption of this network in PD impairs resistance to distracters, which results in attention disorders.
authors.affiliation: University of Lille Nord de France, Lille, France. pebocq@hotmail.fr
authors.forename: Perrine
authors.initials: P
authors.lastname: Bocquillon
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Bourriez
authors.forename: Ernesto
authors.initials: E
authors.lastname: Palmero-Soler
authors.forename: Alain
authors.initials: A
authors.lastname: Destée
authors.forename: Luc
authors.initials: L
authors.lastname: Defebvre
authors.forename: Philippe
authors.initials: P
authors.lastname: Derambure
authors.forename: Kathy
authors.initials: K
authors.lastname: Dujardin
mesh_terms: D000368:Aged; D001479:Basal Ganglia / Q000503:physiopathology*; D001519:Behavior; D016022:Case-Control Studies; D004569:Electroencephalography; D018913:Event-Related Potentials, P300 / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology*; D011930:Reaction Time; D012984:Software; D014057:Tomography, X-Ray Computed