SCALP TOPOGRAPHY OF EVENT-RELATED BRAIN POTENTIALS AND COGNITIVE TRANSITION DURING CHILDHOOD

This study examined the relation between cognitive development and the ontogenesis of event-related brain potentials (ERPs) during childhood . First, the level of cognitive development was assessed in girls betw een 5 and 7 years of age with a standard Piagetian conservation kit. T hen these children performed 2 experimental tasks: a visual selective attention (oddball) task and an experimental analogue of the Piagetian conservation of liquid quantity task. The oddball task required the c hild to count silently the number of rare stimuli presented in a serie s of frequent stimuli. The ERPs elicited in this task showed a positiv e wave with a centroparietal scalp distribution and a maximum amplitud e at around 600 ms poststimulus. In the experimental analogue of the c onservation of liquid quantity task, the child was presented with a ch oice stimulus requiring a left- or right-hand button press. The propor tion of correct responses discriminated successfully between conserver s and nonconservers as established by traditional Piagetian assessment procedures. The ERPs obtained in the experimental analogue of the con servation task were characterized by a broad positivity with a centrop arietal scalp distribution. The broad positivity discriminated signifi cantly between nonconservers and conservers but not between age groups . These findings received additional support from topographic and symm etric dipole analyses of the ERPs. The results of the dipole analysis suggested more anterior ERP sources for the nonconservers during the e arly part of stimulus analysis and more lateralized ERP sources for co nservers during the later part of information processing. It is conclu ded that ERPs may provide a window on the relation between brain matur ation and stage-wise cognitive development.