Haase Katrin, Musielak Isabelle, Warmuth-Moles Leonie, Leberecht Bo, Zolotareva Anna, Mouritsen Henrik, Heyers Dominik
AG Neurosensorik, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany.
Biological Station Rybachy, Zoological Institute of Russian Academy of Sciences, St Petersburg, Russia.
Front Neuroanat. 2022 Mar 7;16:853401. doi: 10.3389/fnana.2022.853401. eCollection 2022.
In night-migratory songbirds, neurobiological and behavioral evidence suggest the existence of a magnetic sense associated with the ophthalmic branch of the trigeminal nerve (V1), possibly providing magnetic positional information. Curiously, neither the unequivocal existence, structural nature, nor the exact location of any sensory structure has been revealed to date. Here, we used neuronal tract tracing to map both the innervation fields in the upper beak and the detailed trigeminal brainstem terminations of the medial and lateral V1 subbranches in the night-migratory Eurasian Blackcap (). The medial V1 subbranch takes its course along the ventral part of the upper beak to innervate subepidermal layers and the mucosa of the nasal cavity, whereas the lateral V1 subbranch runs along dorsolateral levels until the nostrils to innervate mainly the skin of the upper beak. In the trigeminal brainstem, medial V1 terminals innervate both the dorsal part and the ventral, magnetically activated part of the principal sensory trigeminal brainstem nuclei (PrV). In contrast, the lateral V1 subbranch innervates only a small part of the ventral PrV. The spinal sensory trigeminal brainstem nuclei (SpV) receive topographically ordered projections. The medial V1 subbranch mainly innervates rostral and medial parts of SpV, whereas the lateral V1 subbranch mainly innervates the lateral and caudal parts of SpV. The present findings could provide valuable information for further analysis of the trigeminal magnetic sense of birds.
在夜间迁徙的鸣禽中，神经生物学和行为学证据表明，存在一种与三叉神经眼支（V1）相关的磁感，这可能为鸟类提供磁位置信息。奇怪的是，迄今为止，尚未揭示任何感觉结构的确切存在、结构性质或确切位置。在这里，我们使用神经元示踪技术，绘制了夜间迁徙的欧亚黑头莺上喙的神经支配区域以及三叉神经内侧和外侧V1分支在脑干中的详细终止位置。内侧V1分支沿着上喙的腹侧走行，支配鼻腔的表皮下层和黏膜，而外侧V1分支沿着背外侧走行，直至鼻孔，主要支配上喙的皮肤。在三叉神经脑干中，内侧V1终末支配主要感觉三叉神经脑干核（PrV）的背侧部分以及腹侧、被磁激活的部分。相比之下，外侧V1分支仅支配腹侧PrV的一小部分。脊髓感觉三叉神经脑干核（SpV）接受按拓扑顺序排列的投射。内侧V1分支主要支配SpV的 Rostral 和内侧部分，而外侧V1分支主要支配SpV的外侧和尾侧部分。本研究结果可为进一步分析鸟类的三叉神经磁感提供有价值的信息。
