title: Impaired Early Attentional Processes in Parkinson's Disease: A High-Resolution Event-Related Potentials 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. A previous study using the P3 component of the event-related potentials suggested that a reduced ability to resist interference could be responsible for attention disorders at early stages of Parkinson's disease (PD), with a possible role of the dorsolateral prefrontal cortex (DLPFC).
  
  
  METHODS
  Our objective was to better determine the origin of this impairment, by studying an earlier ERP component, the N2, and its subcomponents, as they reflect early inhibition processes and as they are known to have sources in the anterior cingulate cortex (ACC), which is involved together with the DLPFC in inhibition processes. Fifteen early-stage PD patients and 15 healthy controls (HCs) performed a three-stimulus visual oddball paradigm, consisting in detecting target inputs amongst standard stimuli, while resisting interference from distracter ones. A 128-channel electroencephalogram was recorded during this task and the generators of the N2 subcomponents were identified using standardized weighted low-resolution electromagnetic tomography (swLORETA).
  
  
  RESULTS
  PD patients displayed fewer N2 generators than HCs in both the DLPFC and the ACC, for all types of stimuli. In contrast to controls, PD patients did not show any differences between their generators for different N2 subcomponents.
  
  
  CONCLUSIONS
  Our data suggest that impaired inhibition in PD results from dysfunction of the DLPFC and the ACC during the early stages of attentional processes.
authors.affiliation: Clinical Neurophysiology Department, Lille University Medical Center, Lille Cedex, France.
authors.forename: Perrine
authors.initials: P
authors.lastname: Bocquillon
authors.affiliation: Clinical Neurophysiology Department, Lille University Medical Center, Lille Cedex, France; Inserm, U1171, Troubles cognitifs dégénératifs et vasculaires, Université de Lille, Lille Cedex, France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Bourriez
authors.affiliation: Eemagine Medical Imaging Solutions GmbH, Berlin, Germany.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Palmero-Soler
authors.affiliation: Inserm, U1171, Troubles cognitifs dégénératifs et vasculaires, Université de Lille, Lille Cedex, France; Neurology and Movement Disorders Department, Lille University Medical Center, Lille Cedex, France.
authors.forename: Luc
authors.initials: L
authors.lastname: Defebvre
authors.affiliation: Clinical Neurophysiology Department, Lille University Medical Center, Lille Cedex, France; Inserm, U1171, Troubles cognitifs dégénératifs et vasculaires, Université de Lille, Lille Cedex, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Derambure
authors.affiliation: Inserm, U1171, Troubles cognitifs dégénératifs et vasculaires, Université de Lille, Lille Cedex, France; Neurology and Movement Disorders Department, Lille University Medical Center, Lille Cedex, France.
authors.forename: Kathy
authors.initials: K
authors.lastname: Dujardin
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001288:Attention; D001519:Behavior; D001921:Brain / Q000473:pathology; D016022:Case-Control Studies; D003071:Cognition; D003072:Cognition Disorders / Q000503:physiopathology; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D006179:Gyrus Cinguli / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D010300:Parkinson Disease / Q000503:physiopathology*; D011930:Reaction Time