Somatosensory effects on neurons in dorsal cochlear nucleus.
Somatosensory effects on neurons in dorsal cochlear nucleus.
复制标题
对耳蜗背核神经元的体感影响。
DOI：
10.1152/jn.1995.73.2.743
复制
发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Conley,RA
中科院分区：
文献类型：
--
作者：
Young,ED;Nelken,I;Conley,RA
1.单个单位和诱发电位记录在耳蜗背核（DCN）的体感背柱和三叉神经脊束核（统称为MSN的延髓体感核）和触觉体感刺激的电刺激。记录来自瘫痪的去大脑猫。2. DCN主细胞（IV型单位）强烈抑制MSN的电刺激（单50微安双极脉冲）或体感刺激。在DCN的梭形细胞和深层中记录的单位被抑制，表明抑制作用影响两种类型的主细胞（即，梭形细胞和巨细胞）。3.抑制主细胞的中间神经元（II型单位）仅受到电刺激的微弱抑制，并且从未兴奋过，这表明对主细胞的抑制作用不通过II型回路。在DCN/PVCN（后腹侧耳蜗核）边界附近，在MSN中遇到被电刺激兴奋的单位;这些神经元中的一些对声音有反应，而另一些则没有。它们的反应特性与它们是向DCN传递躯体感觉信息的深层抑制性中间神经元的假设是一致的。4. MSN电刺激诱发电位的分析表明，体感输入激活DCN分子层的颗粒细胞系统。Klee和Rall以前的工作的基础上的一个模型被用来表明，诱发电位在DCN的分布可以被解释为导致径向电流产生的DCN分子和梭形细胞层的颗粒细胞输入到梭形细胞和车轮细胞的同步激活。诱发电位的电流源密度分析与该模型一致。因此，分子层中间神经元（侧手翻和星状细胞）是抑制主细胞的第二个可能来源。5.刺激水平越低（20微安）和脉冲对刺激（50- 100-ms的刺激间隔），在梭状细胞层和深层IV型单位中可以识别抑制反应的三个组成部分：在诱发电位开始之前开始的短潜伏期抑制;其定时对应于诱发电位的长潜伏期抑制;以及在诱发电位的上升相上发生的兴奋性分量。兴奋性成分通常被抑制性成分淹没，可能来自颗粒细胞输入;长潜伏期抑制性成分可能来自侧手翻细胞或假设的深层抑制性中间神经元。（400字处截断摘要）
1. Single units and evoked potentials were recorded in dorsal cochlear nucleus (DCN) in response to electrical stimulation of the somatosensory dorsal column and spinal trigeminal nuclei (together called MSN for medullary somatosensory nuclei) and for tactile somatosensory stimuli. Recordings were from paralyzed decerebrate cats. 2. DCN principal cells (type IV units) were strongly inhibited by electrical stimulation (single 50-microA bipolar pulse) in MSN or by somatosensory stimulation. Units recorded in the fusiform cell and deep layers of DCN were inhibited, suggesting that the inhibition affects both types of principal cells (i.e., both fusiform and giant cells). 3. Interneurons (type II units) that inhibit principal cells were only weakly inhibited by electrical stimulation and were never excited, demonstrating that the inhibitory effect on principal cells does not pass through the type II circuit. In the vicinity of the DCN/PVCN (posteroventral cochlear nucleus) boundary, units were encountered that were excited by electrical stimulation in MSN; some of these neurons responded to sound, and some did not. Their response properties are consistent with the hypothesis that they are deep-layer inhibitory interneurons conveying somatosensory information to the DCN. 4. Analysis of the evoked potentials produced by electrical stimulation in MSN suggests that the somatosensory inputs activate the granule cell system of the DCN molecular layer. A model based on previous work by Klee and Rall was used to show that the distribution of evoked potentials in DCN can be explained as resulting from radial currents produced in the DCN molecular and fusiform-cell layers by synchronous activation of granule cells inputs to fusiform and cartwheel cells. Current-source density analysis of the evoked potentials is consistent with this model. Thus molecular layer interneurons (cartwheel and stellate cells) are a second possible source of inhibition to principal cells. 5. With lower stimulus levels (20 microA) and pulse-pair stimuli (50- to 100-ms interstimulus interval), three components of the inhibitory response can be recognized in both fusiform cell layer and deep layer type IV units: a short-latency inhibition that begins before the start of the evoked potential; a longer-latency inhibition whose timing corresponds to the evoked potential; and an excitatory component that occurs on the rising phase of the evoked potential. The excitatory component is usually overwhelmed by the inhibitory components and could be derived from granule cell inputs; the long-latency inhibitory component could be derived from cartwheel cells or the hypothesized deep-layer inhibitory interneurons.(ABSTRACT TRUNCATED AT 400 WORDS)