Gamble Marissa L, Woldorff Marty G
Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA Department of Psychology and Neuroscience, Duke University, Durham, NC, USA.
Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA Department of Psychology and Neuroscience, Duke University, Durham, NC, USA Department of Psychiatry, Duke University, Durham, NC, USA.
Cereb Cortex. 2015 Sep;25(9):2456-65. doi: 10.1093/cercor/bhu047. Epub 2014 Apr 6.
The posterior visual event-related potential (ERP) component, the N2pc, has been widely used to study lateralized shifts of attention within visual arrays. Recently, Gamble and Luck (2011) reported an auditory analog of this activity (the fronto-central "N2ac"), reflecting the lateralized focusing of attention toward a Target sound among 2 simultaneous auditory stimuli. Here, we directed an electrophysiological approach toward understanding auditory Target search within a more complex auditory environment in which rapidly occurring sounds were distributed across both time and space. Trials consisted of ten 40-ms monaural sounds rapidly presented to the 2 ears: 8 medium-pitch tones and 2 deviant sounds (one high and one low). For each block, one deviant type was designated as the Target, which participants needed to identify within each trial to discriminate its tonal quality. The extracted electrophysiological results included a very early enhancement, starting at approximately 50 ms, of a bilateral negative-polarity auditory brain response to the designated Target Deviant (compared with the Nontarget Deviant), followed at approximately 130 ms by the N2ac activity reflecting the lateralized focusing of attention toward that Target. The results delineate the tightly orchestrated sequence of neural processes underlying the detection of, and focusing of attention toward, Target sounds in complex auditory scenes.
视觉后事件相关电位（ERP）成分N2pc已被广泛用于研究视觉阵列中注意力的侧向转移。最近，甘布尔和勒克（2011年）报告了这种活动的听觉类似物（额中央“N2ac”），反映了在两个同时出现的听觉刺激中注意力向目标声音的侧向聚焦。在这里，我们采用一种电生理方法来理解在更复杂的听觉环境中的听觉目标搜索，在这种环境中，快速出现的声音在时间和空间上都有分布。试验包括向两只耳朵快速呈现十个40毫秒的单耳声音：8个中音调音和2个异常声音（一个高音和一个低音）。对于每个组块，一种异常类型被指定为目标，参与者需要在每次试验中识别该目标以辨别其音调质量。提取的电生理结果包括，从大约50毫秒开始，对指定目标异常声音（与非目标异常声音相比）的双侧负极性听觉脑反应有一个非常早期的增强，随后在大约130毫秒时出现N2ac活动，反映了注意力向该目标的侧向聚焦。这些结果描绘了在复杂听觉场景中检测目标声音并将注意力聚焦于目标声音背后紧密协调的神经过程序列。
