NatMEG, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Cognitive Neuroimaging Centre (CoNiC), Lee Kong Chien School of Medicine, Nanyang Technological University, Singapore.
Cognitive Neuroimaging Centre (CoNiC), Lee Kong Chien School of Medicine, Nanyang Technological University, Singapore; Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
Neuroimage. 2021 Jun;233:117962. doi: 10.1016/j.neuroimage.2021.117962. Epub 2021 Mar 18.
The auditory steady-state response (ASSR) is an oscillatory brain response generated by periodic auditory stimuli and originates mainly from the temporal auditory cortices. Recent data show that while the auditory cortices are indeed strongly activated by the stimulus when it is present (ON ASSR), the anatomical distribution of ASSR sources involves also parietal and frontal cortices, indicating that the ASSR is a more complex phenomenon than previously believed. Furthermore, while the ASSR typically continues to oscillate even after the stimulus has stopped (OFF ASSR), very little is known about the characteristics of the OFF ASSR and how it compares to the ON ASSR. Here, we assessed whether the OFF and ON ASSR powers are modulated by the stimulus properties (i.e. volume and pitch), selective attention, as well as individual musical sophistication. We also investigated the cortical source distribution of the OFF ASSR using a melody tracking task, in which attention was directed between uniquely amplitude-modulated melody streams that differed in pitch. The ON and OFF ASSRs were recorded with magnetoencephalography (MEG) on a group of participants varying from low to high degree of musical sophistication. Our results show that the OFF ASSR is different from the ON ASSR in nearly every aspect. While the ON ASSR was modulated by the stimulus properties and selective attention, the OFF ASSR was not influenced by any of these factors. Furthermore, while the ON ASSR was generated primarily from temporal sources, the OFF ASSR originated mainly from the frontal cortex. These findings challenge the notion that the OFF ASSR is merely a continuation of the ON ASSR. Rather, they suggest that the OFF ASSR is an internally-driven signal that develops from an initial sensory processing state (ON ASSR), with both types of ASSRs clearly differing in cortical representation and character. Furthermore, our results show that the ON ASSR power was enhanced by selective attention at cortical sources within each of the bilateral frontal, temporal, parietal and insular lobes. Finally, the ON ASSR proved sensitive to musicality, demonstrating positive correlations between musical sophistication and ASSR power, as well as with the degree of attentional ASSR modulation at the left and right parietal cortices. Taken together, these results show new aspects of the ASSR response, and demonstrate its usefulness as an effective tool for analysing how selective attention interacts with individual abilities in music perception.
听觉稳态响应（ASSR）是一种由周期性听觉刺激产生的振荡脑反应，主要来源于颞叶听觉皮质。最近的数据表明，当刺激存在时（ON ASSR），听觉皮质确实会被强烈激活，而 ASSR 源的解剖分布还涉及顶叶和额叶皮质，这表明 ASSR 是一种比以前认为的更为复杂的现象。此外，尽管 ASSR 通常在刺激停止后仍继续振荡（OFF ASSR），但对 OFF ASSR 的特征及其与 ON ASSR 的比较知之甚少。在这里，我们评估了 OFF 和 ON ASSR 功率是否受刺激特性（即音量和音高）、选择性注意以及个体音乐复杂性的调制。我们还使用旋律跟踪任务研究了 OFF ASSR 的皮质源分布，在该任务中，注意力在具有独特幅度调制的旋律流之间定向，这些旋律流在音高上有所不同。ON 和 OFF ASSR 是使用一组从音乐水平较低到较高的参与者的脑磁图（MEG）记录的。我们的结果表明，OFF ASSR 在几乎所有方面都与 ON ASSR 不同。虽然 ON ASSR 受刺激特性和选择性注意的调制，但 OFF ASSR 不受这些因素的任何影响。此外，虽然 ON ASSR 主要由颞叶源产生，但 OFF ASSR 主要源自额叶。这些发现挑战了 OFF ASSR 仅是 ON ASSR 的延续的观点。相反，它们表明 OFF ASSR 是一种内部驱动的信号，它源自初始的感觉处理状态（ON ASSR），两种类型的 ASSR 在皮质表示和特征上显然存在差异。此外，我们的结果表明，选择性注意增强了每个双侧额、颞、顶和岛叶皮质源的 ON ASSR 功率。最后，ON ASSR 对音乐性敏感，表现出与音乐复杂性之间的正相关关系，以及与左右顶叶皮质注意力调节程度的正相关关系。综上所述，这些结果展示了 ASSR 反应的新方面，并证明了它作为一种分析选择性注意如何与音乐感知个体能力相互作用的有效工具的有用性。
