Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander-University Erlangen-Nürnberg, 91054 Erlangen, Germany.
Neuroscience Laboratory, University Hospital Erlangen, 91058 Erlangen, Germany.
J Neurosci. 2023 Nov 1;43(44):7429-7440. doi: 10.1523/JNEUROSCI.1247-23.2023. Epub 2023 Oct 4.
Selective attention to one of several competing speakers is required for comprehending a target speaker among other voices and for successful communication with them. It moreover has been found to involve the neural tracking of low-frequency speech rhythms in the auditory cortex. Effects of selective attention have also been found in subcortical neural activities, in particular regarding the frequency-following response related to the fundamental frequency of speech (speech-FFR). Recent investigations have, however, shown that the speech-FFR contains cortical contributions as well. It remains unclear whether these are also modulated by selective attention. Here we used magnetoencephalography to assess the attentional modulation of the cortical contributions to the speech-FFR. We presented both male and female participants with two competing speech signals and analyzed the cortical responses during attentional switching between the two speakers. Our findings revealed robust attentional modulation of the cortical contribution to the speech-FFR: the neural responses were higher when the speaker was attended than when they were ignored. We also found that, regardless of attention, a voice with a lower fundamental frequency elicited a larger cortical contribution to the speech-FFR than a voice with a higher fundamental frequency. Our results show that the attentional modulation of the speech-FFR does not only occur subcortically but extends to the auditory cortex as well. Understanding speech in noise requires attention to a target speaker. One of the speech features that a listener can use to identify a target voice among others and attend it is the fundamental frequency, together with its higher harmonics. The fundamental frequency arises from the opening and closing of the vocal folds and is tracked by high-frequency neural activity in the auditory brainstem and in the cortex. Previous investigations showed that the subcortical neural tracking is modulated by selective attention. Here we show that attention affects the cortical tracking of the fundamental frequency as well: it is stronger when a particular voice is attended than when it is ignored.
选择性注意几个竞争说话者之一是理解目标说话者在其他声音中并与他们成功交流所必需的。此外，人们发现它涉及听觉皮层中低频言语节奏的神经跟踪。选择性注意的影响也在皮质下神经活动中发现，特别是与言语基频（言语 FFR）相关的频率跟随反应。然而，最近的研究表明，言语 FFR 也包含皮质贡献。目前尚不清楚这些是否也受到选择性注意的调节。在这里，我们使用脑磁图来评估皮质对言语 FFR 的贡献的注意力调制。我们向男性和女性参与者呈现两个竞争的语音信号，并在两个说话者之间的注意力切换期间分析皮质反应。我们的发现揭示了对言语 FFR 的皮质贡献的强大注意力调制：当说话者被关注时，神经反应比被忽略时更高。我们还发现，无论注意力如何，基频较低的声音比基频较高的声音引起的言语 FFR 的皮质贡献更大。我们的研究结果表明，言语 FFR 的注意力调制不仅发生在皮质下，而且还扩展到听觉皮层。在噪声中理解言语需要注意目标说话者。听众可以用来在其他声音中识别目标声音并关注它的语音特征之一是基频及其更高的谐波。基频源于声带的开闭，由听觉脑干和皮质中的高频神经活动跟踪。先前的研究表明，皮质下神经跟踪受选择性注意的调节。在这里，我们表明注意力也会影响基频的皮质跟踪：当特别关注某个声音时，它比忽略时更强。
