Szczepaniak W S, Møller A R
Department of Neurological Surgery, University of Pittsburgh School of Medicine, PA 15213.
Electroencephalogr Clin Neurophysiol. 1993 Nov-Dec;88(6):508-15. doi: 10.1016/0168-5597(93)90039-r.
It is known that some neurons in the external nucleus of the inferior colliculus (ICX) receive both auditory and somatosensory input. In recordings of evoked potentials from the ICX in the rat we show evidence that somatosensory activation can modify the auditory response to click stimulation. Electrical stimulation of the median nerve affects the click-evoked response that is recorded from the surface of the ICX and different components of the response were affected differently. The magnitude of the changes was dependent on the time interval between electrical stimulation of the median nerve and presentation of the click stimulation. The amplitude of the two earliest peaks in the click-evoked ICX response increased slightly (16% and 20%, respectively; average of recordings in 10 animals) as a result of stimulation of the median nerve, while the amplitudes of two later peaks decreased as a result of stimulation of the median nerve (the average decrease in amplitude of these two peaks in recordings in 10 animals was 18 and 26%, respectively). The latencies of the 3 peaks we studied were only slightly affected, and the maximal change was 0.07 and 0.25 msec, respectively, for the 2 earliest peaks. The decrease in the amplitude of specific peaks of the ICX response confirms that some neurons of the extralemniscal system receive both auditory and somatosensory input, and that such somatosensory input is mainly inhibitory on these neurons. We interpret the increase in the amplitude of the early peak to be a result of median nerve stimulation caused by a decreased centrifugal inhibitory influence on superior olivary neurons.
已知下丘外侧核（ICX）中的一些神经元同时接受听觉和体感输入。在对大鼠ICX诱发电位的记录中，我们发现有证据表明体感激活可以改变对点击刺激的听觉反应。正中神经的电刺激会影响从ICX表面记录到的点击诱发反应，且反应的不同成分受到的影响不同。变化的幅度取决于正中神经电刺激与点击刺激呈现之间的时间间隔。由于正中神经的刺激，点击诱发的ICX反应中最早出现的两个峰值的幅度略有增加（分别为16%和20%；10只动物记录的平均值），而由于正中神经的刺激，随后两个峰值的幅度则下降（10只动物记录中这两个峰值幅度的平均下降分别为18%和26%）。我们研究的3个峰值的潜伏期仅受到轻微影响，最早出现的两个峰值的最大变化分别为0.07和0.25毫秒。ICX反应特定峰值幅度的下降证实，外侧丘系系统的一些神经元同时接受听觉和体感输入，并且这种体感输入对这些神经元主要起抑制作用。我们将早期峰值幅度的增加解释为正中神经刺激导致对上橄榄核神经元的离心抑制影响减弱的结果。
