Stimulus Dependence of Contralateral Dominance in Human Auditory Cortex
Stimulus Dependence of Contralateral Dominance in Human Auditory Cortex
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DOI：
10.1002/hbm.22673
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发表时间：
2015-03-01
影响因子：
4.8
通讯作者：
Steinmann, Iris
中科院分区：
文献类型：
--
作者：
Gutschalk, Alexander;Steinmann, Iris
听觉系统通常被认为很少表现出对侧优势，但关于单耳声音诱发的活动的对侧优势的生理报告差异很大。在这里，我们表明，这种变化的一部分是刺激依赖性的：血氧水平依赖（BOLD）响应32秒的单耳呈现未调制的噪声（UN）显示激活对侧听觉皮层（AC）和失活在同侧AC相比，非刺激基线。缓慢的调幅（AM）噪声引起强烈的对侧激活和最小的同侧激活。AM与UN的对比度用于分离与慢幅度调制本身相关的fMRI活动。这种差异激活是双边的，但在对侧AC中仍然更强。在脑磁图（MEG）中，反应主要是稳态活动相位锁定到振幅调制。这种脑磁图活动没有表现出一致的对侧优势的听众。皮质下BOLD激活强烈对侧后，上级橄榄复合体（SOC），并没有表现出显着差异调制和UN。一名胼胝体参与者表现出与该组相似的fMRI激活，裁定经胼胝体传输不太可能是同侧增强或同侧失活的来源。这些结果表明，上升活动继SOC是强烈占主导地位的刺激耳对侧。与此相反，BOLD和MEG活动的慢幅度调制的一部分是双边的，只观察到在AC。同侧失活可能会使对侧BOLD优势的测量产生偏差，应在未来的研究中予以考虑。《脑地图》36：883-896，2015年。(c)2014 Wiley Periodicals，Inc.
The auditory system is often considered to show little contralateral dominance but physiological reports on the contralateral dominance of activity evoked by monaural sound vary widely. Here, we show that part of this variation is stimulus-dependent: blood oxygen level dependent (BOLD) responses to 32 s of monaurally presented unmodulated noise (UN) showed activation in contralateral auditory cortex (AC) and deactivation in ipsilateral AC compared to nonstimulus baseline. Slow amplitude-modulated (AM) noise evoked strong contralateral activation and minimal ipsilateral activation. The contrast of AM-versus-UN was used to separate fMRI activity related to the slow amplitude modulation per se. This difference activation was bilateral although still stronger in contralateral AC. In magnetoencephalography (MEG), the response was dominated by the steady-state activity phase locked to the amplitude modulation. This MEG activity showed no consistent contralateral dominance across listeners. Subcortical BOLD activation was strongly contralateral subsequent to the superior olivary complex (SOC) and showed no significant difference between modulated and UN. An acallosal participant showed similar fMRI activation as the group, ruling transcallosal transmission an unlikely source of ipsilateral enhancement or ipsilateral deactivation. These results suggest that ascending activity subsequent to the SOC is strongly dominant contralateral to the stimulus ear. In contrast, the part of BOLD and MEG activity related to slow amplitude modulation is more bilateral and only observed in AC. Ipsilateral deactivation can potentially bias measures of contralateral BOLD dominance and should be considered in future studies. Hum Brain Mapp 36:883-896, 2015.(c) 2014 Wiley Periodicals, Inc.