مدولاسیون از بالا به پایین فرآیندهای توجه انتخابی در کودکان

It has been demonstrated in adults that attention can modulate very early stages of perceptual/cognitive processing, but it has not been determined if this capacity for modulation develops with age. We investigated early attentional processes in parallel and serial visual search tasks in 40 children 7–12 years old, using event-related potentials (ERPs). Two single-feature pop-out tasks were used to assess parallel processing; a conjunction of features task was used to study serial processing. There were significant decreases in latencies with age for the peaks measured [posterior P1, N1 and anterior P2 (P2a)]. P1 and N1 latency effects also varied with trial type and were consistent with top-down modulation of processing, which differed between the parallel tasks. P2a amplitude for the hit trials decreased with increasing age for the colour and serial tasks. Increasing R>L hemispheric asymmetries with age in P2a amplitude were seen on non-target trials for the size and serial tasks only, reflecting serial processing. These data demonstrate that developmental changes in visual selective attention for early stages of processing are continuing through childhood, and that there is top-down modulation at these latencies in children.