Inferior Frontal Gyrus Activation Predicts Individual Differences in Perceptual Learning of Cochlear-Implant Simulations
Inferior Frontal Gyrus Activation Predicts Individual Differences in Perceptual Learning of Cochlear-Implant Simulations
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DOI：
10.1523/jneurosci.4040-09.2010
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发表时间：
2010-05-26
影响因子：
5.3
通讯作者：
Scott, Sophie K.
中科院分区：
文献类型：
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作者：
Eisner, Frank;McGettigan, Carolyn;Scott, Sophie K.
本研究旨在探讨人工耳蜗（CI）模拟感知学习的神经可塑性。听力正常的听众进行了培训，语音编码和频谱移位语音模拟CI，而皮质反应与功能性磁共振成像（fMRI）测量。声码语音被频谱反转的条件提供了可学习性和适应性的控制。行为措施显示出相当大的个体差异，无论是在学习理解退化语音的能力，和语音工作记忆容量。在神经元方面，左侧的上级颞沟和额下回（IFG）的区域是敏感的可学习性的模拟，但只有前额叶皮层的活动与个体间的差异，可懂度分数和语音工作记忆。左角回（AG）的一个区域显示了一种激活模式，反映了实验过程中的学习，AG和IFG的活动的协变调制的可学习性的刺激。这些结果表明，在听者的能力，以适应语音编码和频谱转移的语音的变化，部分反映在招聘更高层次的语言过程在前额叶皮层的差异，这种变化可能进一步依赖于左额下回和角回之间的功能联系。左下前额叶皮质的参与差异，其与后顶叶区的协变，因此，可能是在CI用户的临床人群中观察到的语音感知技能的变化的基础。
This study investigated the neural plasticity associated with perceptual learning of a cochlear implant (CI) simulation. Normal-hearing listeners were trained with vocoded and spectrally shifted speech simulating a CI while cortical responses were measured with functional magnetic resonance imaging (fMRI). A condition in which the vocoded speech was spectrally inverted provided a control for learnability and adaptation. Behavioral measures showed considerable individual variability both in the ability to learn to understand the degraded speech, and in phonological working memory capacity. Neurally, left-lateralized regions in superior temporal sulcus and inferior frontal gyrus (IFG) were sensitive to the learnability of the simulations, but only the activity in prefrontal cortex correlated with interindividual variation in intelligibility scores and phonological working memory. A region in left angular gyrus (AG) showed an activation pattern that reflected learning over the course of the experiment, and covariation of activity in AG and IFG was modulated by the learnability of the stimuli. These results suggest that variation in listeners' ability to adjust to vocoded and spectrally shifted speech is partly reflected in differences in the recruitment of higher-level language processes in prefrontal cortex, and that this variability may further depend on functional links between the left inferior frontal gyrus and angular gyrus. Differences in the engagement of left inferior prefrontal cortex, and its covariation with posterior parietal areas, may thus underlie some of the variation in speech perception skills that have been observed in clinical populations of CI users.