Development of preparatory activity indexed by the contingent negative variation in children

Objectives: The present study investigated the effect of age on task-specific preparatory activation induced by a spatial cue using the central cue Posner's paradigm. The behavioral responses and the contingent negative variation (CNV) generated between S1 (the warning stimulus) and S2 (the imperative stimulus) were compared between 16 healthy children (8-13 years old) and 17 healthy young adults (18-23 years old). Methods: The EEG was recorded from 20 scalp sites of the International 10-20 system. The complete trial period included a central directional cue that was on for 300 m s and an attentive waiting period lasting 1360 m s. Finally, a peripheral target appeared, subtending a visual angle of 4.56 degrees and situated 2.28 degrees eccentrically in the horizontal meridian. The early and late components of the CNV appearing in the period between cue and target were analyzed. Results: The CNV of children showed no contralateral cortical activation related to motor preparation. However, the young adults showed contralateral activation to the cue over motor areas. Both children and young adults showed cortical activation in posterior sensory areas, displaying a pattern of activation contralateral to the cue. Also, a positive parietal component appeared in children during the CNV period. Conclusions: These results suggest that the motor preparation system in children is less mature than the sensory preparatory system. The children may have used strategies and brain areas different from those of the young adults to prepare for stimuli and responses. (C) 2009 Elsevier Inc. All rights reserved.