Institute of Psychology I, University of Leipzig, Seeburgstr, 14-20, D-04103 Leipzig, Germany.
BMC Neurosci. 2010 Oct 7;11:126. doi: 10.1186/1471-2202-11-126.
We investigated the processing of task-irrelevant and unexpected novel sounds and its modulation by working-memory load in children aged 9-10 and in adults. Environmental sounds (novels) were embedded amongst frequently presented standard sounds in an auditory-visual distraction paradigm. Each sound was followed by a visual target. In two conditions, participants evaluated the position of a visual stimulus (0-back, low load) or compared the position of the current stimulus with the one two trials before (2-back, high load). Processing of novel sounds were measured with reaction times, hit rates and the auditory event-related brain potentials (ERPs) Mismatch Negativity (MMN), P3a, Reorienting Negativity (RON) and visual P3b.
In both memory load conditions novels impaired task performance in adults whereas they improved performance in children. Auditory ERPs reflect age-related differences in the time-window of the MMN as children showed a positive ERP deflection to novels whereas adults lack an MMN. The attention switch towards the task irrelevant novel (reflected by P3a) was comparable between the age groups. Adults showed more efficient reallocation of attention (reflected by RON) under load condition than children. Finally, the P3b elicited by the visual target stimuli was reduced in both age groups when the preceding sound was a novel.
Our results give new insights in the development of novelty processing as they (1) reveal that task-irrelevant novel sounds can result in contrary effects on the performance in a visual primary task in children and adults, (2) show a positive ERP deflection to novels rather than an MMN in children, and (3) reveal effects of auditory novels on visual target processing.
我们研究了儿童（9-10 岁）和成人在工作记忆负荷下对无关和意外新声音的处理及其调节。在视听分心范式中，环境声音（新颖声音）嵌入在经常呈现的标准声音中。每个声音后面都跟着一个视觉目标。在两种条件下，参与者评估视觉刺激的位置（0 回，低负载）或比较当前刺激与前两个刺激的位置（2 回，高负载）。通过反应时、击中率和听觉事件相关脑电位（MMN、P3a、重新定向负波（RON）和视觉 P3b）来测量新颖声音的处理。
在两种记忆负载条件下，新颖声音都会降低成人的任务表现，但会提高儿童的表现。听觉事件相关电位反映了 MMN 时间窗口中与年龄相关的差异，因为儿童对新颖声音表现出正的 ERP 偏转，而成年人则缺乏 MMN。对任务无关新颖声音的注意转换（由 P3a 反映）在两个年龄组之间是相似的。与儿童相比，成年人在负载条件下对注意的再分配更有效（由 RON 反映）。最后，当前一个声音是新颖声音时，两个年龄组的视觉目标刺激诱发的 P3b 都会减少。
我们的结果为新颖性处理的发展提供了新的见解，因为它们（1）揭示了无关新颖声音在儿童和成人的视觉主要任务表现中可能产生相反的影响，（2）在儿童中表现出对新颖声音的正 ERP 偏转，而不是 MMN，以及（3）揭示了听觉新颖声音对视觉目标处理的影响。
