Department of Communication Sciences and Disorders, University of South Florida, Tampa, Florida.
J Neurophysiol. 2021 Sep 1;126(3):803-815. doi: 10.1152/jn.00609.2020. Epub 2021 Jul 21.
The present study measured scalp potentials in response to low-frequency, narrowband noise bursts changing location in the front, azimuthal plane. At question was whether selective auditory attention has a modulatory effect on the cortical encoding of spatial change and whether older listeners with normal-hearing thresholds would show depressed cortical representation for spatial changes relative to younger listeners. Young and older normal-hearing listeners were instructed to either passively listen to the stimulus presentation or actively attend to a single location (either 30° left or right of midline) and detect when a noise stream moved to the attended location. Prominent peaks of the electroencephalographic scalp waveforms were compared across groups, locations, and attention conditions. In addition, an opponent-channel model of spatial coding was performed to capture the effect of attention on spatial-change tuning. Younger listeners showed not only larger responses overall but a greater dynamic range in their response to location changes. Results suggest that younger listeners were acquiring and encoding key spatial cues at early cortical processing areas. On the other hand, each group exhibited modulatory effects of attention to spatial-change tuning, indicating that both younger and older listeners selectively attend to space in a manner that amplifies the available signal. In complex acoustic scenes, listeners take advantage of spatial cues to selectively attend to sounds that are deemed immediately relevant. At the neural level, selective attention amplifies electrical responses to spatial changes. We tested whether older and younger listeners have comparable modulatory effects of attention to stimuli moving in the free field. Results indicate that although older listeners do have depressed overall responses, selective attention enhances spatial-change tuning in younger and older listeners alike.
本研究测量了低频、窄带噪声突发在额平面中的位置变化时的头皮电位。问题是选择性听觉注意力是否对空间变化的皮质编码具有调制作用，以及具有正常听力阈值的老年听众相对于年轻听众是否会表现出空间变化的皮质表示降低。年轻和年长的正常听力听众被指示要么被动地听刺激呈现，要么主动关注单个位置（中线左侧或右侧 30°），并检测噪声流是否移动到所关注的位置。比较了各组、位置和注意条件下的脑电图头皮波形的突出峰值。此外，还进行了空间编码的对立通道模型，以捕捉注意力对空间变化调谐的影响。年轻听众不仅总体反应更大，而且对位置变化的反应动态范围也更大。结果表明，年轻听众在早期皮质处理区域正在获取和编码关键的空间线索。另一方面，每个组都表现出对空间变化调谐的注意力调制效应，表明年轻和年长的听众都以一种放大可用信号的方式选择性地关注空间。在复杂的声学场景中，听众利用空间线索有选择地关注被认为立即相关的声音。在神经水平上，选择性注意力会放大对空间变化的电反应。我们测试了老年和年轻听众对在自由场中移动的刺激的注意力是否具有可比的调制作用。结果表明，尽管老年听众的总体反应确实降低了，但选择性注意力增强了年轻和年长听众的空间变化调谐。
