Ruhr University Bochum, Faculty of Psychology, D-44780, Bochum, Germany; Leibniz Research Centre for Working Environment and Human Factors, D-44139, Dortmund, Germany.
Leibniz Research Centre for Working Environment and Human Factors, D-44139, Dortmund, Germany.
Neuropsychologia. 2019 Aug;131:160-170. doi: 10.1016/j.neuropsychologia.2019.05.023. Epub 2019 May 27.
Speech perception in "cocktail-party" situations, in which a sound source of interest has to be extracted out of multiple irrelevant sounds, poses a remarkable challenge to the human auditory system. Studies on structural and electrophysiological correlates of auditory selective spatial attention revealed critical roles of the posterior temporal cortex and the N2 event-related potential (ERP) component in the underlying processes. Here, we explored effects of transcranial direct current stimulation (tDCS) to posterior temporal cortex on neurophysiological correlates of auditory selective spatial attention, with a specific focus on the N2. In a single-blind, sham-controlled crossover design with baseline and follow-up measurements, monopolar anodal and cathodal tDCS was applied for 16 min to the right posterior superior temporal cortex. Two age groups of human subjects, a younger (n = 20; age 18-30 yrs) and an older group (n = 19; age 66-77 yrs), completed an auditory free-field multiple-speakers localization task while ERPs were recorded. The ERP data showed an offline effect of anodal, but not cathodal, tDCS immediately after DC offset for targets contralateral, but not ipsilateral, to the hemisphere of tDCS, without differences between groups. This effect mainly consisted in a substantial increase of the N2 amplitude by 0.9 μV (SE 0.4 μV; d = 0.40) compared with sham tDCS. At the same point in time, cortical source localization revealed a reduction of activity in ipsilateral (right) posterior parietal cortex. Also, localization error was improved after anodal, but not cathodal, tDCS. Given that both the N2 and the posterior parietal cortex are involved in processes of auditory selective spatial attention, these results suggest that anodal tDCS specifically enhanced inhibitory attentional brain processes underlying the focusing onto a target sound source, possibly by improved suppression of irrelevant distracters.
在“鸡尾酒会”场景中，人类听觉系统需要从多个不相关的声音中提取出感兴趣的声源，这对其构成了巨大挑战。有关听觉选择性空间注意的结构和电生理相关性的研究表明，后颞叶皮层和 N2 事件相关电位（ERP）成分在这些过程中起着关键作用。在这里，我们探索了经颅直流电刺激（tDCS）对听觉选择性空间注意的神经生理相关性的影响，特别关注 N2。在一项单盲、假刺激对照的交叉设计中，我们在基线和随访测量时，将单极阳极和阴极 tDCS 应用于右侧后上颞叶皮层 16 分钟。两个年龄组的人类受试者，一个年轻组（n=20；年龄 18-30 岁）和一个老年组（n=19；年龄 66-77 岁），在听觉自由场多扬声器定位任务中完成任务，同时记录 ERP。ERP 数据显示，在直流电关闭后立即出现阳极 tDCS 的离线效应，但阴极 tDCS 没有，这种效应仅针对刺激对侧，而不是同侧，且同侧刺激对侧半球的效应在两组之间没有差异。这种效应主要表现为与假刺激相比，N2 振幅增加了 0.9μV（SE 0.4μV；d=0.40）。在同一时间点，皮质源定位显示同侧（右）后顶叶皮层的活动减少。此外，阳极 tDCS 后定位误差得到改善，但阴极 tDCS 没有。鉴于 N2 和后顶叶皮层都参与了听觉选择性空间注意的过程，这些结果表明，阳极 tDCS 特别增强了目标声源注意力集中的抑制性注意力处理过程，可能是通过提高对无关干扰的抑制。
