P300 sequence effects differ between children and adults for auditory stimuli

Variation of the P300 component was studied in normal children and adults d uring an auditory oddball paradigm. In children, the target stimuli that we re preceded by a large number of standard stimuli elicited about twice as l arge P300 with a significantly shorter latency, a more widespread distribut ion, and an earlier positivity in the frontal area than those that were pre ceded by a small number of standard stimuli. The P300 variation was not as marked in adults as in children. Based on the context updating theory of th e P300, the finding suggests that a long intertarget interval (ITI) results in a profound decay of the neural representation of the target stimulus in children; consequently, mon resources are needed to update the neural repr esentation, and the target may even be processed as a novel input. The P300 variation may provide information about the brain functions related to mem ory, attention, and orienting in children. This variation should be conside red when assessing cognitive brain functions with event-related potentials in children.