Laboratory for Brain, Music and Sound Research (BRAMS), Montreal, Canada ; Department of Psychology, University of Montreal, Montreal, Canada ; Centre for Research on Brain, Language and Music (CRBLM), Montreal, Canada.
Laboratory for Brain, Music and Sound Research (BRAMS), Montreal, Canada ; Department of Psychology, University of Montreal, Montreal, Canada ; Centre for Research on Brain, Language and Music (CRBLM), Montreal, Canada ; Montreal Neurological Institute, McGill University, Montreal, Canada.
PLoS One. 2014 Jan 15;9(1):e85442. doi: 10.1371/journal.pone.0085442. eCollection 2014.
Selective attention is the mechanism that allows focusing one's attention on a particular stimulus while filtering out a range of other stimuli, for instance, on a single conversation in a noisy room. Attending to one sound source rather than another changes activity in the human auditory cortex, but it is unclear whether attention to different acoustic features, such as voice pitch and speaker location, modulates subcortical activity. Studies using a dichotic listening paradigm indicated that auditory brainstem processing may be modulated by the direction of attention. We investigated whether endogenous selective attention to one of two speech signals affects amplitude and phase locking in auditory brainstem responses when the signals were either discriminable by frequency content alone, or by frequency content and spatial location. Frequency-following responses to the speech sounds were significantly modulated in both conditions. The modulation was specific to the task-relevant frequency band. The effect was stronger when both frequency and spatial information were available. Patterns of response were variable between participants, and were correlated with psychophysical discriminability of the stimuli, suggesting that the modulation was biologically relevant. Our results demonstrate that auditory brainstem responses are susceptible to efferent modulation related to behavioral goals. Furthermore they suggest that mechanisms of selective attention actively shape activity at early subcortical processing stages according to task relevance and based on frequency and spatial cues.
选择性注意是一种机制，它允许人们将注意力集中在一个特定的刺激上，同时过滤掉一系列其他的刺激，例如在嘈杂的房间里专注于单一的对话。关注一个声源而不是另一个声源会改变人类听觉皮层的活动，但目前尚不清楚注意力是否会调节不同的声学特征，如声音音调和说话者位置，调节皮质下活动。使用双耳分听范式的研究表明，听觉脑干处理可能受到注意力方向的调节。我们研究了当两个语音信号中的一个受到内源性选择性注意时，是否会影响听觉脑干反应的幅度和相位锁定，而这些信号仅通过频率内容或频率内容和空间位置来区分。在两种情况下，对语音的频率跟随反应都显著受到调制。调制是特定于与任务相关的频带的。当同时存在频率和空间信息时，效果更强。反应模式在参与者之间是可变的，并且与刺激的心理物理可辨别性相关，这表明这种调制是具有生物学意义的。我们的结果表明，听觉脑干反应易受与行为目标相关的传出调制的影响。此外，它们表明，选择性注意机制根据任务相关性以及基于频率和空间线索，主动塑造早期皮质下处理阶段的活动。
