Specific task anticipation versus unspecific orienting reaction during early contingent negative variation.
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.
Bender
Stephan
S
Department for Child and Adolescent Psychiatry, Psychiatric Clinic, University of Heidelberg, Blumenstrasse 8, D-69115 Heidelberg, Germany. stephan_bender@med.uni-heidelberg.de
Resch
Franz
F
Weisbrod
Matthias
M
Oelkers-Ax
Rieke
R
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