The organization of plurisegmental mechanosensitive interneurons in the central nervous system of the wandering spider Cupiennius salei.
The organization of plurisegmental mechanosensitive interneurons in the central nervous system of the wandering spider Cupiennius salei.
复制标题
游走蜘蛛 Cupiennius salei 中枢神经系统中多节段机械敏感中间神经元的组织。
DOI：
10.1007/bf00297489
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发表时间：
1990
影响因子：
3.6
通讯作者：
Gronenberg,W
中科院分区：
文献类型：
--
作者：
Gronenberg,W
在蜘蛛中，中枢神经系统（CNS）的大部分由纵束穿过的融合节段神经节组成，纵束与感觉神经髓鞘有精确的关系，并含有大的多节段中间神经元的纤维。这些中间神经元对各种机械刺激的反应进行了电生理研究，并通过细胞内染色揭示了它们的单侧或双侧结构。单侧中间神经元访问CNS一侧的所有神经节。它们通过侵入腿部神经节并投射到特定纵向束的感觉神经元从单腿或所有同侧腿接收机械感觉输入。单侧中间神经元的解剖组织表明，它们的轴突传递信息给所有同侧腿神经节。双侧中间神经元分为对称神经元和非对称神经元。后者对身体一侧所有腿的刺激做出反应，其树突位于中枢神经系统同一侧的感觉束之间。解剖学证据表明，他们的终端侵入所有四个对侧腿神经节。双侧对称的多节段中间神经元在融合的腹侧神经节的两半中具有树突状分支。它们对8条腿中任何一条的刺激都有反应。作为第三类细胞，上行神经元在融合的腹侧神经节中具有单侧或双侧树突状分支，并且在大脑的后腹侧区域中显示出泡状轴突。它们的反应特征与其他多节段中间神经元相似。下行神经元具有相反的结构极性，在大脑中产生并终止于融合的腹侧神经节的节段区域。下行神经元对视觉刺激表现出强烈的反应。所有记录的神经元中大约有50%只对单一类型的机械感受器（触觉毛、耳毛或狭缝感受器）的刺激做出反应，而其余的则对各种感受器的刺激做出反应。然而，这些功能上的差异并没有在解剖学上得到明显的反映。多节段中间神经元的功能意义进行了讨论相对于感觉收敛和协调运动输出的腿。某些多节段性中间神经元和他们的父母纵向束的响应特性之间的比较表明，束本身并不反映一个模态特定的组织。
In spiders the bulk of the central nervous system (CNS) consists of fused segmental ganglia traversed by longitudinal tracts, which have precise relationships with sensory neuropils and which contain the fibers of large plurisegmental interneurons. The responses of these interneurons to various mechanical stimuli were studied electrophysiologically, and their unilateral or bilateral structure was revealed by intracellular staining. Unilateral interneurons visit all the neuromeres on one side of the CNS. They receive mechanosensory input either from a single leg or from all ipsilateral legs via sensory neurons that invade leg neuromeres and project into specific longitudinal tracts. The anatomical organization of unilateral interneurons suggests that their axons impart their information to all ipsilateral leg neuromeres. Bilateral interneurons are of two kinds, symmetric and asymmetric neurons. The latter respond to stimulation of all legs on one side of the body, having their dendrites amongst sensory tracts of the same side of the CNS. Anatomical evidence suggests that their terminals invade all four contralateral leg neuromeres. Bilaterally symmetrical plurisegmental interneurons have dendritic arborizations in both halves of the fused ventral ganglia. They respond to the stimulation of any of the 8 legs. A third class of cells, the ascending neurons have unilateral or bilateral dendritic arborizations in the fused ventral ganglia and show blebbed axons in postero-ventral regions of the brain. Their response characteristics are similar to those of other plurisegmental interneurons. Descending neurons have opposite structural polarity, arising in the brain and terminating in segmental regions of the fused ventral ganglia. Descending neurons show strong responses to visual stimulation. Approximately 50% of all the recorded neurons respond exclusively to stimulation of a single type of mechanoreceptor (either tactile hairs, or trichobothria, or slit sensilla), while the rest respond to stimulation of a variety of sensilla. However, these functional differences are not obviously reflected by the anatomy. The functional significance of plurisegmental interneurons is discussed with respect to sensory convergence and the coordination of motor output to the legs. A comparison between the response properties of certain plurisegmental interneurons and their parent longitudinal tracts suggests that the tracts themselves do not reflect a modality-specific organization.