Integrative mechanisms controlling directional sensitivity of an identified sensory interneuron
Integrative mechanisms controlling directional sensitivity of an identified sensory interneuron
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控制已识别感觉中间神经元方向敏感性的综合机制
作者：
G. Jacobs;J. Miller;R. Murphey
在蟋蟀的颈传入系统中，几个已确定的中间神经元对风刺激表现出定向敏感性：这些细胞的尖峰频率取决于相对于动物身体的风向。研究了其中一个中间神经元（中间神经元10-3）定向敏感性的影响因素。该细胞有3个树突状分支，分布在腹神经节末端的3个不同区域。采用两种独立的方法，证明了树突对风刺激具有不同的感受野。首先，分离出一小片丝状毛发，选择性地刺激它们的传入神经到单个树突上。在每种情况下，细胞的反应都与贴片中传入事件的接受野相匹配。其次，在细胞内记录期间，通过立体解剖显微镜定向的激光束用于原位光灭活细胞的一小部分。通过分离或切除单个树突，评估3个树突对整个感受野的贡献。虽然整个细胞的感受野可以通过所有3个树突的感受野相加来预测，但细胞的精确定向灵敏度不能通过每个树突的感受野的简单线性相加来预测。发现有两个因素可以解释这种求和的非线性。第一个因素是来自腹末神经节内其他中间神经元的多突触抑制。确定了激活中间神经元10-3抑制的风向，并确定了激活抑制途径的特定种类的丝状传入事件。抑制的净效果是通过选择性地降低细胞对特定兴奋输入的反应来“锐化”1-3的方向敏感性。第二个影响定向灵敏度的因素是中间神经元的复杂电解剖。利用激光光灭活技术确定了脉冲起始区（SIZ）的可能位置。突触输入到3个不同分支的相对效果，然后根据它们与SIZ的不同电紧张距离来解释。在本报告获得的数据的基础上，我们提出了一个定性模型的基础上的方向灵敏度在这个细胞。
Several identified interneurons in the cricket cercal afferent system display directional sensitivity to wind stimuli: the spike frequency of these cells depends on the wind direction with respect to the animal's body. Factors determining the directional sensitivity of one of these identified interneurons (interneuron 10-3) were studied in detail. This cell has 3 dendritic branches that arborize in 3 distinct regions of the terminal abdominal ganglion. Using 2 independent methods, it was demonstrated that the dendrites have different receptive fields to wind stimuli. First, small patches of filiform hairs, whose afferents projected to individual dendrites, were isolated and selectively stimulated. In each case the response of the cell matched the receptive field of the afferents in the patch. Second, a laser beam directed through the stereo dissecting microscope was used to photoinactivate small portions of the cell in situ during intracellular recording. By isolating or ablating individual dendrites, the contributions of each of the 3 dendrites to the overall receptive field were assessed. Although the receptive field of the whole cell could be predicted by a summation of the receptive fields of all 3 dendrites, the precise directional sensitivity of the cell could not be predicted by a simple linear summation of the receptive fields of each dendrite. Two factors were found to account for this nonlinearity of summation. The first factor was polysynaptic inhibition from other interneurons within the terminal abdominal ganglion. Wind directions that activate inhibition in interneuron 10-3 were identified, and the specific classes of filiform afferents that activate the inhibitory pathway were determined. The net effect of the inhibition was to "sharpen" the directional sensitivity of 1–3 by selectively decreasing the cell's response to specific excitatory inputs. The second factor that contributed to directional sensitivity was the complex electroanatomy of the interneuron. The probable location of the spike-initiating zone (SIZ) was determined by using the laser photoinactivation technique. The relative efficacies of synaptic inputs onto the 3 different branches were then interpreted with respect to their different electrotonic distances from the SIZ. On the basis of the data obtained in this report, we present a qualitative model for the basis of directional sensitivity in this cell.
猫膝状 W 细胞的形态和生理特性：与 X 和 Y 细胞的比较。
影响因子：
2.5
作者：
Stanford,LR;Friedlander,MJ;Sherman,SM
通讯作者：
Sherman,SM
染色、功能和生长神经元的图像增强。
DOI：
--
发表时间：
1986
期刊：
Society of General Physiologists series
影响因子：
--
作者：
Kater,SB;Cohan,CS;Jacobs,GA;Miller,JP
通讯作者：
Miller,JP