Bilinguals at the "cocktail party": Dissociable neural activity in auditory-linguistic brain regions reveals neurobiological basis for nonnative listeners' speech-in-noise recognition deficits
Bilinguals at the "cocktail party": Dissociable neural activity in auditory-linguistic brain regions reveals neurobiological basis for nonnative listeners' speech-in-noise recognition deficits
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DOI：
10.1016/j.bandl.2015.02.002
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发表时间：
2015-04-01
影响因子：
2.5
通讯作者：
Dexter, Lauren
中科院分区：
文献类型：
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作者：
Bidelman, Gavin M.;Dexter, Lauren
我们研究了在双语者中观察到的一致缺陷：对非母语的噪声中语音（SIN）理解较差。我们记录了单语和双语听众在噪声中对对比语音的反应时的神经电失配电位。行为上，后期双语者需要类似的10 dB更有利的信噪比，以匹配单语者的SIN能力。皮层活动的源分析表明，两组的上级颞回（STG）的反应潜伏期随着噪声的单调增加，这表明听觉皮层的语音表征平行退化。相比之下，我们发现不同的语音编码组内额下回（IFG）相邻的布罗卡区，在非母语的听众观察到的噪音延迟抵消单语。值得注意的是，大脑行为的对应性在语言组之间是双重分离的：STG激活预测双语者的SIN，而IFG激活预测单语者的表现。我们推断，高阶脑区的行为补偿，以提高贫困的感觉表征，但只有当退化的语音招聘语言的大脑机制下游从最初的认知感觉输入。(C)2015 Elsevier Inc. All rights reserved.
We examined a consistent deficit observed in bilinguals: poorer speech-in-noise (SIN) comprehension for their nonnative language. We recorded neuroelectric mismatch potentials in mono- and bi-lingual listeners in response to contrastive speech sounds in noise. Behaviorally, late bilinguals required similar to 10 dB more favorable signal-to-noise ratios to match monolinguals' SIN abilities. Source analysis of cortical activity demonstrated monotonic increase in response latency With noise in superior temporal gyrus (STG) for both groups, suggesting parallel degradation of speech representations in auditory cortex. Contrastively, we found differential speech encoding between groups within inferior frontal gyrus (IFG) adjacent to Broca's area where noise delays observed in nonnative listeners were offset in monolinguals. Notably, brain-behavior correspondences double dissociated between language groups: STG activation predicted bilinguals' SIN, whereas IFG activation predicted monolinguals' performance. We infer higher-order brain areas act compensatorily to enhance impoverished sensory representations but only when degraded speech recruits linguistic brain mechanisms downstream from initial auditory-sensory inputs. (C) 2015 Elsevier Inc. All rights reserved.