Wang Xin, Li An-An, Wu Fei-Jian
College of Life Science, Central China Normal University, Wuhan, China.
Sheng Li Xue Bao. 2010 Aug 25;62(4):309-16.
Sound duration plays important role in acoustic communication. Information of acoustic signal is mainly encoded in the amplitude and frequency spectrum of different durations. Duration selective neurons exist in the central auditory system including inferior colliculus (IC) of frog, bat, mouse and chinchilla, etc., and they are important in signal recognition and feature detection. Two generally accepted models, which are "coincidence detector model" and "anti-coincidence detector model", have been raised to explain the mechanism of neural selective responses to sound durations based on the study of IC neurons in bats. Although they are different in details, they both emphasize the importance of synaptic integration of excitatory and inhibitory inputs, and are able to explain the responses of most duration-selective neurons. However, both of the hypotheses need to be improved since other sound parameters, such as spectral pattern, amplitude and repetition rate, could affect the duration selectivity of the neurons. The dynamic changes of sound parameters are believed to enable the animal to effectively perform recognition of behavior related acoustic signals. Under free field sound stimulation, we analyzed the neural responses in the IC and auditory cortex of mouse and bat to sounds with different duration, frequency and amplitude, using intracellular or extracellular recording techniques. Based on our work and previous studies, this article reviews the properties of duration selectivity in central auditory system and discusses the mechanisms of duration selectivity and the effect of other sound parameters on the duration coding of auditory neurons.
声音时长在声学通讯中起着重要作用。声学信号的信息主要编码在不同时长的幅度和频谱中。时长选择性神经元存在于包括青蛙、蝙蝠、小鼠和绒鼠等动物的下丘脑（IC）在内的中枢听觉系统中，它们在信号识别和特征检测中很重要。基于对蝙蝠IC神经元的研究，已经提出了两种普遍接受的模型，即“巧合探测器模型”和“反巧合探测器模型”，以解释神经对声音时长的选择性反应机制。尽管它们在细节上有所不同，但都强调兴奋性和抑制性输入的突触整合的重要性，并且能够解释大多数时长选择性神经元的反应。然而，这两种假设都需要改进，因为其他声音参数，如频谱模式、幅度和重复率，可能会影响神经元的时长选择性。声音参数的动态变化被认为能使动物有效地识别与行为相关的声学信号。在自由场声音刺激下，我们使用细胞内或细胞外记录技术，分析了小鼠和蝙蝠的IC和听觉皮层对不同时长、频率和幅度声音的神经反应。基于我们的工作和先前的研究，本文综述了中枢听觉系统中时长选择性的特性，并讨论了时长选择性的机制以及其他声音参数对听觉神经元时长编码的影响。
