Bleeck Stefan, Sayles Mark, Ingham Neil J, Winter Ian M
Institute of Sound and Vibration Research, University of Southampton, Highfield, United Kingdom.
Hear Res. 2006 Feb;212(1-2):176-84. doi: 10.1016/j.heares.2005.12.005. Epub 2006 Feb 3.
The responses to two identical, consecutive pure tone stimuli with varying inter-stimulus intervals (delta ts) were measured for 89 neurons in the cochlear nucleus of the anaesthetised guinea pig. We observed two main effects; either a decrease (suppression) or an increase (facilitation) in response to the second tone followed by an exponential recovery. Response behaviour correlated with the unit type; primary-like, primary-like with notch and transient-chopper units showed a recovery from suppression that was very similar to that already reported in the auditory nerve. For chopper units the strength of the adaptation was correlated with the units regularity of spike discharge; sustained chopper (CS) units showed less suppression than transient choppers. Onset units showed complete suppression at short delta ts. Pause/Build (PB) units responded with increased activity to the second tone. In contrast to previous studies in the cochlear nucleus the recovery from suppression or facilitation was well described by a single exponential function, enabling us to define a recovery time constant and a maximum suppression/facilitation. There appeared to be a hierarchy in the time constant of recovery with PB and CS units showing the longest recovery times and onset units showing the shortest.
在麻醉的豚鼠耳蜗核中，对89个神经元测量了对两个相同、连续的纯音刺激的反应，刺激间隔（δt）不同。我们观察到两种主要效应：对第二个音调的反应要么降低（抑制）要么增加（易化），随后呈指数恢复。反应行为与单位类型相关；类初级、带缺口的类初级和瞬态斩波器单位显示出从抑制中恢复的情况，这与听觉神经中已经报道的情况非常相似。对于斩波器单位，适应强度与单位的放电规律性相关；持续斩波器（CS）单位的抑制比瞬态斩波器少。起始单位在短δt时表现出完全抑制。暂停/增强（PB）单位对第二个音调的反应是活动增加。与先前在耳蜗核中的研究不同，抑制或易化的恢复可以用单个指数函数很好地描述，这使我们能够定义恢复时间常数和最大抑制/易化。恢复时间常数似乎存在层次结构，PB和CS单位的恢复时间最长，起始单位的恢复时间最短。
