Riecke Lars, Scharke Wolfgang, Valente Giancarlo, Gutschalk Alexander
Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, University Hospital, RWTH Aachen University, Aachen, Germany.
PLoS One. 2014 Sep 26;9(9):e108045. doi: 10.1371/journal.pone.0108045. eCollection 2014.
Auditory selective attention plays an essential role for identifying sounds of interest in a scene, but the neural underpinnings are still incompletely understood. Recent findings demonstrate that neural activity that is time-locked to a particular amplitude-modulation (AM) is enhanced in the auditory cortex when the modulated stream of sounds is selectively attended to under sensory competition with other streams. However, the target sounds used in the previous studies differed not only in their AM, but also in other sound features, such as carrier frequency or location. Thus, it remains uncertain whether the observed enhancements reflect AM-selective attention. The present study aims at dissociating the effect of AM frequency on response enhancement in auditory cortex by using an ongoing auditory stimulus that contains two competing targets differing exclusively in their AM frequency. Electroencephalography results showed a sustained response enhancement for auditory attention compared to visual attention, but not for AM-selective attention (attended AM frequency vs. ignored AM frequency). In contrast, the response to the ignored AM frequency was enhanced, although a brief trend toward response enhancement occurred during the initial 15 s. Together with the previous findings, these observations indicate that selective enhancement of attended AMs in auditory cortex is adaptive under sustained AM-selective attention. This finding has implications for our understanding of cortical mechanisms for feature-based attentional gain control.
听觉选择性注意在识别场景中感兴趣的声音方面起着至关重要的作用，但其神经基础仍未完全被理解。最近的研究结果表明，当调制的声音流在与其他声音流的感觉竞争中被选择性地注意时，与特定幅度调制（AM）时间锁定的神经活动在听觉皮层中会增强。然而，先前研究中使用的目标声音不仅在其AM方面不同，在其他声音特征方面也不同，例如载波频率或位置。因此，观察到的增强是否反映了AM选择性注意仍不确定。本研究旨在通过使用一种持续的听觉刺激来区分AM频率对听觉皮层反应增强的影响，该刺激包含两个仅在AM频率上不同的竞争目标。脑电图结果显示，与视觉注意相比，听觉注意有持续的反应增强，但AM选择性注意（被关注的AM频率与被忽略的AM频率）则没有。相反，对被忽略的AM频率的反应增强了，尽管在最初的15秒内出现了短暂的反应增强趋势。与先前的研究结果一起，这些观察结果表明，在持续的AM选择性注意下，听觉皮层中被关注的AM的选择性增强是适应性的。这一发现对我们理解基于特征的注意力增益控制的皮层机制具有启示意义。
