Jacob M, Weddell G
J Comp Neurol. 1975 May 1;161(1):115-23. doi: 10.1002/cne.901610109.
A study has been made of the macroscopic, microscopic and electron-microscopical appearance of intersegmental neural connections in the rat. Macroscopically, spinal roots and ganglia of adjacent segments were frequently observed to be linked by discrete, slender strands, mainly in the lumbosacral region where the roots are long. When examined under the light microscope, even the smallest was found to contain as many as 72 myelinated fibres with a range of diameters between 1.5-14 mu-m. The were commonly accompanied by blood vessels. Connections, when present, contributed to as much as 6-28% of the total number of myelinated axons in dorsal roots. Under the electron microscope, links between dorsal roots, or between dorsal roots and adjacent ganglia, contained unmyelinated fibres comparable in numbers to those found in the dorsal roots themselves. In links between ventral roots and ganglia the numbers of unmyelinated fibres proportionally exceeded those found in ventral roots. The presence of these connections may account for the reported finding of undamaged nerve fibres in the dorsal roots after dorsal root sectioning or ganglionectomy and in the ventral roots after ventral root sectioning.
对大鼠节段间神经连接的宏观、微观及电子显微镜下表现进行了一项研究。在宏观层面，经常观察到相邻节段的脊神经根和神经节通过离散的细束相连，主要位于神经根较长的腰骶部区域。在光学显微镜下检查时，发现即使是最细的束也包含多达72条有髓纤维，直径范围在1.5 - 14微米之间。它们通常伴有血管。这些连接在存在时，占背根中有髓轴突总数的6 - 28%。在电子显微镜下，背根之间或背根与相邻神经节之间的连接含有无髓纤维，其数量与背根自身中的无髓纤维数量相当。在腹根与神经节之间的连接中，无髓纤维的数量按比例超过腹根中的数量。这些连接的存在可能解释了在背根切断术或神经节切除术后背根中以及腹根切断术后腹根中报道的未受损神经纤维的发现。
