Rouiller E, de Ribaupierre Y, Toros-Morel A, de Ribaupierre F
Hear Res. 1981 Sep;5(1):81-100. doi: 10.1016/0378-5955(81)90028-9.
The activity of 418 medial geniculate body (MGB) units was studied in response to repetitive acoustic pulses in 35 nitrous oxide anaesthetized cats. The proportion of MGB neurons insensitive to repetitive clicks was close to 30%. On the basis of their pattern of discharge, the responsive units were divided into three categories. The majority of them (71%), classified as "lockers', showed discharges precisely time-locked to the individual clicks of the train. A few units (8%), called "groupers', had discharges loosely synchronized to low-rate repetitive clicks. When the spikes were not synchronized, the cell had transient or sustained responses for a limited frequency range and was classified as a "special responder' (21%). Responses of "lockers' were time-locked up to a limiting rate, which varied between 10 and 800 Hz; half of the "lockers' had a limiting rate of locking equal to or higher than 100 Hz. The degree of entrainment, defined as the probability that each click evokes at least one spike, regularly decreases for increasing rates; on the other hand, the precision of locking increasing increases with frequency. The time jitter observed at 100 Hz might be as small as 0.2 ms and was 1.2 ms on average. The population of "lockers' can mark with precision the transients of complex sounds and has response properties still compatible with a temporal coding of the fundamental frequency of most animal vocalizations.
在35只接受氧化亚氮麻醉的猫中，研究了418个内侧膝状体（MGB）单元对重复性声脉冲的反应。对重复性咔哒声不敏感的MGB神经元比例接近30%。根据其放电模式，将反应性单元分为三类。其中大多数（71%）被归类为“锁相器”，其放电与一连串单个咔哒声精确锁相。少数单元（8%）被称为“分组器”，其放电与低速率重复性咔哒声松散同步。当尖峰不同步时，细胞在有限频率范围内有瞬态或持续反应，被归类为“特殊反应者”（21%）。“锁相器”的反应在达到一个极限速率之前都是锁相的，该极限速率在10至800赫兹之间变化；一半的“锁相器”锁相极限速率等于或高于100赫兹。夹带程度定义为每次咔哒声引发至少一个尖峰的概率，随着速率增加而有规律地降低；另一方面，锁相精度随频率增加而提高。在100赫兹时观察到的时间抖动可能小至0.2毫秒，平均为1.2毫秒。“锁相器”群体能够精确标记复杂声音的瞬态，并且具有与大多数动物发声基频的时间编码仍兼容的反应特性。
