Evaluation of spatial validity-invalidity by the P300 component in children and young adults.

The influence of cerebral maturity on the neurocognitive evaluation of target stimuli that have been cued by a spatial directional central cue, which, validly or invalidly, indicates the spatial position of the upcoming target has been investigated. ERPs and behavioural responses were recorded in 18 children and 20 young adults. P3a and P3b amplitudes were analyzed in the valid and invalid trials to assess possible differences between children and young adults. Young adults showed more activation in anterior (P3a) and posterior (P3b) areas in the invalid than the valid condition, whereas children only showed greater activation in P3b. This may be due to the later maturation of the frontal cortex than the more posterior sites. Children also showed a greater P3 component amplitude and a topography shifting to occipital sites, irrespective of the experimental condition.