Auditory Neuroscience Laboratory, Department of Communication Sciences, Northwestern University, 2240 Campus Drive, Evanston, IL 60208, USA.
Hear Res. 2011 Feb;272(1-2):125-34. doi: 10.1016/j.heares.2010.10.009. Epub 2010 Nov 20.
Low-frequency temporal information present in speech is critical for normal perception, however the neural mechanism underlying the differentiation of slow rates in acoustic signals is not known. Data from the rat trigeminal system suggest that the paralemniscal pathway may be specifically tuned to code low-frequency temporal information. We tested whether this phenomenon occurs in the auditory system by measuring the representation of temporal rate in lemniscal and paralemniscal auditory thalamus and cortex in guinea pig. Similar to the trigeminal system, responses measured in auditory thalamus indicate that slow rates are differentially represented in a paralemniscal pathway. In cortex, both lemniscal and paralemniscal neurons indicated sensitivity to slow rates. We speculate that a paralemniscal pathway in the auditory system may be specifically tuned to code low-frequency temporal information present in acoustic signals. These data suggest that somatosensory and auditory modalities have parallel sub-cortical pathways that separately process slow rates and the spatial representation of the sensory periphery.
语音中的低频时间信息对于正常感知至关重要，然而，目前尚不清楚神经机制如何区分声信号中的慢频率。来自大鼠三叉神经系统的数据表明，旁外侧索可能专门用于编码低频时间信息。我们通过测量豚鼠听觉丘脑和皮层中的声索和旁声索听觉丘脑和皮层中时间率的表示，来测试这一现象是否发生在听觉系统中。与三叉神经系统相似，在听觉丘脑中测量的反应表明，慢频率在旁声索途径中以不同的方式表示。在皮层中，声索和旁声索神经元都对慢频率敏感。我们推测，听觉系统中的旁声索途径可能专门用于编码声信号中的低频时间信息。这些数据表明，躯体感觉和听觉模态具有平行的皮质下通路，分别处理慢频率和感觉外围的空间表示。
