Segregation of vowels and consonants in human auditory cortex: evidence for distributed hierarchical organization
Segregation of vowels and consonants in human auditory cortex: evidence for distributed hierarchical organization
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DOI：
10.3389/fpsyg.2010.00232
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发表时间：
2010-01-01
影响因子：
3.8
通讯作者：
Rauschecker, Josef P.
中科院分区：
文献类型：
--
作者：
Obleser, Jonas;Leaver, Amber M.;Rauschecker, Josef P.
语音信号由连续的辅音和元音组成，必须在人类听觉皮层中进行解码和编码，以确保语音的鲁棒识别和分类。我们使用小体素功能性磁共振成像来研究由辅音-元音音节引起的局部大脑激活模式中编码的信息，以及由控制组的噪声突发。首先，在控制非特异性声学处理（音节与带通噪声，在“经典”减法设计中）时，观察到前外侧上级颞叶皮层的激活。第二，分类器算法，这是训练和测试迭代的数据从所有受试者区分局部大脑激活模式，产生分离的皮层补丁歧视元音类别与补丁歧视停止辅音类别在整个上级颞叶皮层，但与区域差异的平均分类精度。重叠（体素正确分类两个语音类别）是令人惊讶的稀疏。第三，贷款进一步的结果，语音噪声差异的分类一般优于语音语音分类，与左前区，语音语音分类精度显着更好的显着例外上级。这些数据表明，声学语音特征编码在复杂但稀疏重叠的局部神经活动模式，分层分布在听觉皮层的不同区域。这些多重模式中明显的冗余可以部分解释音位表征的稳健性。
The speech signal consists of a continuous stream of consonants and vowels, which must be de-and encoded in human auditory cortex to ensure the robust recognition and categorization of speech sounds. We used small-voxel functional magnetic resonance imaging to study information encoded in local brain activation patterns elicited by consonant-vowel syllables, and by a control set of noise bursts. First, activation of anterior-lateral superior temporal cortex was seen when controlling for unspecific acoustic processing (syllables versus band-passed noises, in a "classic" subtraction-based design). Second, a classifier algorithm, which was trained and tested iteratively on data from all subjects to discriminate local brain activation patterns, yielded separations of cortical patches discriminative of vowel category versus patches discriminative of stop-consonant category across the entire superior temporal cortex, yet with regional differences in average classification accuracy. Overlap (voxels correctly classifying both speech sound categories) was surprisingly sparse. Third, lending further plausibility to the results, classification of speech-noise differences was generally superior to speech-speech classifications, with the notable exception of a left anterior region, where speech-speech classification accuracies were significantly better. These data demonstrate that acoustic-phonetic features are encoded in complex yet sparsely overlapping local patterns of neural activity distributed hierarchically across different regions of the auditory cortex. The redundancy apparent in these multiple patterns may partly explain the robustness of phonemic representations.