Department of Biological and Medical Psychology University of Bergen, Bergen, Norway ; Department of Medical Engineering, Haukeland University Hospital Bergen, Norway.
Department of Experimental Psychology, Otto-von-Guericke University Magdeburg, Germany.
Front Psychol. 2014 Jun 11;5:549. doi: 10.3389/fpsyg.2014.00549. eCollection 2014.
To differentiate between stop-consonants, the auditory system has to detect subtle place of articulation (PoA) and voice-onset time (VOT) differences between stop-consonants. How this differential processing is represented on the cortical level remains unclear. The present functional magnetic resonance (fMRI) study takes advantage of the superior spatial resolution and high sensitivity of ultra-high-field 7 T MRI. Subjects were attentively listening to consonant-vowel (CV) syllables with an alveolar or bilabial stop-consonant and either a short or long VOT. The results showed an overall bilateral activation pattern in the posterior temporal lobe during the processing of the CV syllables. This was however modulated strongest by PoA such that syllables with an alveolar stop-consonant showed stronger left lateralized activation. In addition, analysis of underlying functional and effective connectivity revealed an inhibitory effect of the left planum temporale (PT) onto the right auditory cortex (AC) during the processing of alveolar CV syllables. Furthermore, the connectivity result indicated also a directed information flow from the right to the left AC, and further to the left PT for all syllables. These results indicate that auditory speech perception relies on an interplay between the left and right ACs, with the left PT as modulator. Furthermore, the degree of functional asymmetry is determined by the acoustic properties of the CV syllables.
为了区分塞音，听觉系统必须检测塞音之间细微的发音部位（PoA）和嗓音起始时间（VOT）差异。这种差异处理在皮质水平上是如何表现的还不清楚。本功能磁共振成像（fMRI）研究利用了超高场 7T MRI 的优越空间分辨率和高灵敏度。被试专注于听带有齿龈或双唇塞音的辅音-元音（CV）音节，并且 VOT 有短或长之分。结果显示，在处理 CV 音节时，双侧颞叶后部呈现出总体激活模式。然而，这种模式主要受到 PoA 的调制，使得带有齿龈塞音的音节显示出更强的左侧偏侧化激活。此外，对潜在功能和有效连接的分析表明，在处理齿龈 CV 音节时，左侧颞平面（PT）对右侧听觉皮层（AC）存在抑制作用。此外，连接结果还表明，对于所有音节，信息从右到左 AC 再到左 PT 呈定向流动。这些结果表明，听觉言语感知依赖于左、右 AC 之间的相互作用，左侧 PT 作为调制器。此外，功能不对称的程度取决于 CV 音节的声学特性。
