Uppenkamp Stefan, Johnsrude Ingrid S, Norris Dennis, Marslen-Wilson William, Patterson Roy D
Centre for the Neural Basis of Hearing, Department of Physiology, University of Cambridge, Cambridge CB2 3EG, UK.
Neuroimage. 2006 Jul 1;31(3):1284-96. doi: 10.1016/j.neuroimage.2006.01.004. Epub 2006 Feb 28.
It is commonly assumed that, in the cochlea and the brainstem, the auditory system processes speech sounds without differentiating them from any other sounds. At some stage, however, it must treat speech sounds and nonspeech sounds differently, since we perceive them as different. The purpose of this study was to delimit the first location in the auditory pathway that makes this distinction using functional MRI, by identifying regions that are differentially sensitive to the internal structure of speech sounds as opposed to closely matched control sounds. We analyzed data from nine right-handed volunteers who were scanned while listening to natural and synthetic vowels, or to nonspeech stimuli matched to the vowel sounds in terms of their long-term energy and both their spectral and temporal profiles. The vowels produced more activation than nonspeech sounds in a bilateral region of the superior temporal sulcus, lateral and inferior to regions of auditory cortex that were activated by both vowels and nonspeech stimuli. The results suggest that the perception of vowel sounds is compatible with a hierarchical model of primate auditory processing in which early cortical stages of processing respond indiscriminately to speech and nonspeech sounds, and only higher regions, beyond anatomically defined auditory cortex, show selectivity for speech sounds.
人们通常认为，在耳蜗和脑干中，听觉系统处理语音时不会将其与其他声音区分开来。然而，在某个阶段，它必须对语音和非语音进行不同的处理，因为我们能感知到它们的不同。本研究的目的是通过功能磁共振成像（fMRI）确定听觉通路中进行这种区分的首个位置，即识别对语音内部结构有不同敏感度的区域，与匹配度高的对照声音进行对比。我们分析了9名右利手志愿者的数据，他们在聆听自然元音和合成元音或与元音声音在长期能量以及频谱和时间特征方面相匹配的非语音刺激时接受扫描。在颞上沟的双侧区域，元音比非语音产生了更多激活，该区域位于由元音和非语音刺激均激活的听觉皮层区域的外侧和下方。结果表明，元音声音的感知与灵长类动物听觉处理的层级模型相符，在该模型中，早期皮层处理阶段对语音和非语音声音无差别响应，只有超出解剖学定义的听觉皮层的更高区域才对语音声音表现出选择性。
