Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
Brain Res. 2009 Dec 15;1303:48-60. doi: 10.1016/j.brainres.2009.09.059. Epub 2009 Sep 25.
Recordings were made from single neurons in the rat's central nucleus of the inferior colliculus (ICc). Binaural responses were studied when dichotic tone bursts with various interaural-level differences were presented simultaneously or with a contralateral delay. These dichotic tone bursts allowed us to probe temporal changes in the effect produced by an ipsilateral sound on a contralaterally elicited response. Most of the neurons in the rat's ICc were excited by contralateral and inhibited by ipsilateral stimulation. For the majority of neurons with excitatory/inhibitory interactions, the early part of an ipsilateral stimulus caused stronger inhibition than the late part. The ipsilateral stimulus frequently produced an excitatory or inhibitory "offset" effect that was apparent soon after cessation of the stimulus. For many neurons, this aftereffect substantially changed the strength and temporal firing pattern of the response elicited by a lagging contralateral stimulus. Our results suggest that there are time-dependent changes in the effect of ipsilateral stimulation on the pattern and strength of responses to contralateral stimulation. These effects frequently outlast the duration of a leading ipsilateral stimulus. These characteristics of binaural interaction likely reflect the time courses of converging excitatory and inhibitory synaptic inputs to ICc neurons as well as the intrinsic membrane properties of those neurons.
记录取自大鼠下丘脑中核（ICc）的单个神经元。当同时或对侧延迟呈现具有各种耳间水平差异的双音声爆发时，研究了双耳反应。这些双音声爆发使我们能够探测同侧声音对同侧诱发反应产生的影响的时间变化。大鼠 ICc 中的大多数神经元对同侧刺激兴奋，对同侧刺激抑制。对于大多数具有兴奋/抑制相互作用的神经元，同侧刺激的早期部分比晚期部分引起更强的抑制。同侧刺激经常产生明显的兴奋性或抑制性“偏移”效应，在刺激停止后很快出现。对于许多神经元来说，这种后效极大地改变了滞后对侧刺激诱发的反应的强度和时间发放模式。我们的结果表明，同侧刺激对同侧刺激的模式和强度的影响存在时间依赖性变化。这些效应经常持续超过主导同侧刺激的持续时间。这些双耳相互作用的特征可能反映了向 ICc 神经元汇聚的兴奋性和抑制性突触输入的时间过程，以及这些神经元的内在膜特性。
