title: Specific task anticipation versus unspecific orienting reaction during early contingent negative variation.
abstract: OBJECTIVE
  To investigate whether a warning stimulus in a forewarned reaction time task elicits only an unspecific orienting reaction or task specific motor cortex activity.
  
  
  METHODS
  We examined the time-course of alpha event-related desynchronization (ERD) as an indicator for primary motor cortex activation in an auditory contingent negative variation (CNV) paradigm with an interstimulus interval of 3 s in healthy subjects between 6 and 18 years using a 64 channel high-density sensor array.
  
  
  RESULTS
  We replicated a wide frontal distribution for the initial CNV component (iCNV), while only during late CNV (lCNV) a centro-parietal negativity resembling the 'Bereitschaftspotential' occurred. However, an early alpha-ERD over the central area contralateral to the side of the response movement followed the imperative stimulus already during the iCNV-interval. This early alpha-ERD was highly significantly lateralised and was even more prominent during iCNV than during lCNV indicating an activation of the contralateral sensorimotor cortex already during iCNV.
  
  
  CONCLUSIONS
  We conclude that early task specific preparatory motor processes (which might reflect the retrieval of a motor program from memory) were elicited by the warning stimulus. These preparatory processes clearly exceeded an unspecific orienting reaction as early alpha-ERD was influenced by the side of the anticipated movement.
authors.affiliation: Department for Child and Adolescent Psychiatry, Psychiatric Clinic, University of Heidelberg, Blumenstrasse 8, D-69115 Heidelberg, Germany. stephan_bender@med.uni-heidelberg.de
authors.forename: Stephan
authors.initials: S
authors.lastname: Bender
authors.forename: Franz
authors.initials: F
authors.lastname: Resch
authors.forename: Matthias
authors.initials: M
authors.lastname: Weisbrod
authors.forename: Rieke
authors.initials: R
authors.lastname: Oelkers-Ax
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000293:Adolescent; D002648:Child; D003265:Contingent Negative Variation / Q000502:physiology*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D009949:Orientation / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D013997:Time Factors