Nabatiyan A, Poulet J F A, de Polavieja G G, Hedwig B
Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom.
J Neurophysiol. 2003 Oct;90(4):2484-93. doi: 10.1152/jn.00259.2003.
Auditory pattern recognition by the CNS is a fundamental process in acoustic communication. Because crickets communicate with stereotyped patterns of constant frequency syllables, they are established models to investigate the neuronal mechanisms of auditory pattern recognition. Here we provide evidence that for the neural processing of amplitude-modulated sounds, the instantaneous spike rate rather than the time-averaged neural activity is the appropriate coding principle by comparing both coding parameters in a thoracic interneuron (Omega neuron ON1) of the cricket (Gryllus bimaculatus) auditory system. When stimulated with different temporal sound patterns, the analysis of the instantaneous spike rate demonstrates that the neuron acts as a low-pass filter for syllable patterns. The instantaneous spike rate is low at high syllable rates, but prominent peaks in the instantaneous spike rate are generated as the syllable rate resembles that of the species-specific pattern. The occurrence and repetition rate of these peaks in the neuronal discharge are sufficient to explain temporal filtering in the cricket auditory pathway as they closely match the tuning of phonotactic behavior to different sound patterns. Thus temporal filtering or "pattern recognition" occurs at an early stage in the auditory pathway.
中枢神经系统对听觉模式的识别是声音交流中的一个基本过程。由于蟋蟀通过固定频率音节的刻板模式进行交流，它们是研究听觉模式识别神经机制的成熟模型。在这里，我们通过比较双斑蟋（Gryllus bimaculatus）听觉系统中一个胸段中间神经元（欧米伽神经元ON1）的两种编码参数，提供证据表明，对于调幅声音的神经处理，瞬时发放率而非时间平均神经活动是合适的编码原则。当用不同的时间声音模式进行刺激时，对瞬时发放率的分析表明，该神经元对音节模式起到低通滤波器的作用。在高音节率时瞬时发放率较低，但当音节率类似于物种特异性模式时，瞬时发放率会产生明显的峰值。这些神经元放电中峰值的出现和重复率足以解释蟋蟀听觉通路中的时间滤波，因为它们与趋声行为对不同声音模式的调谐密切匹配。因此，时间滤波或“模式识别”发生在听觉通路的早期阶段。
