Introduction

Recently, an additional trigeminothalamic tract – the dorsal trigeminothalamic tract – has been described in human brainstems by our group next to the known ventral trigeminothalamic tract. As various elements of the trigeminal system are known to be organised in a somatotopic fashion, the question arose whether the fibres within the trigeminal root show specific distributions patterns in their contribution to the ventral trigeminothalamic tract and dorsal trigeminothalamic tract specifically.

Methods

This study investigated the arrangement of the fibres in the trigeminal root by combining various imaging methods in the pons of 11 post-mortem specimens. The pons were investigated by polarised light imaging (PLI) (n = 4; to quantify fibre orientation; 100 µm interslice distance), histochemical staining methods (n = 3; to visualise the internal myeloarchitecture; 60 µm) and ultra-high field, post-mortem magnetic resonance imaging (MRI) (n = 4; for tractography; 500 µm interslice distance).

Results

This study shows that the fibres, from the point where the trigeminal root enters the brainstem, are distinctly arranged by their contribution to the ventral trigeminothalamic tract and dorsal trigeminothalamic tract. This finding is supported by both post-mortem, ultra-high dMRI and different light microscopy techniques.

Conclusion

The data from this study suggest that the fibres in the superior half of the root contribute mainly to the ventral trigeminothalamic tract, whereas the fibres in the inferior half mainly contribute to the dorsal trigeminothalamic tract. Such a somatotopic organisation could possibly create new insights into the anatomical origin of trigeminal neuralgia and the clinical relevance of this somatotopic organisation should therefore be further explored.

中文翻译：

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绘制三叉神经根进入区及其桥脑纤维分布模式。

介绍

最近，我们小组在人类脑干中描述了一个额外的三叉丘脑束——背侧三叉丘脑束，与已知的腹侧三叉丘脑束相邻。由于已知三叉神经系统的各种元素以体位方式组织，因此问题在于三叉神经根内的纤维是否显示出特定的分布模式，即它们对腹侧三叉丘脑束和背侧三叉丘脑束的贡献。

方法

本研究通过结合各种成像方法在 11 个死后标本的脑桥中研究了三叉神经根中纤维的排列。通过偏振光成像 (PLI)（n = 4；量化纤维方向；100 µm 层间距离）、组织化学染色方法（n = 3；以可视化内部骨髓结构；60 µm）和超高场对脑桥进行研究，验尸磁共振成像 (MRI)（n = 4；用于纤维束成像；500 µm 层间距离）。

结果

这项研究表明，从三叉神经根进入脑干的那一点，这些纤维通过它们对三叉丘脑腹侧束和三叉丘脑背侧束的贡献而明显排列。这一发现得到了验尸、超高 dMRI 和不同光学显微镜技术的支持。

结论

这项研究的数据表明，根上半部的纤维主要作用于三叉丘脑腹侧束，而下半部的纤维主要作用于三叉丘脑背侧束。这种体位组织可能会为三叉神经痛的解剖起源提供新的见解，因此应进一步探索这种体位组织的临床相关性。