Matunis Ashley, Iwamoto Ryotaro, Stacy Emma, Abe Kenta, Tamura Shunki, Kambe Yuki, Itokazu Takahide, Hikida Takatoshi, Sato Tatsuo K, Sato Takashi R
Department of Biology, College of Charleston, Charleston, SC, 29424, USA.
Department of Neuroscience, Medical University of South Carolina, Charleston, SC, 29425, USA.
Sci Rep. 2025 Jul 1;15(1):22007. doi: 10.1038/s41598-025-05382-6.
Somatotopy serves as a fundamental principle underlying sensory information processing, traditionally emphasized in the study of the cerebral cortex. However, little effort has been directed towards unraveling the spatial organization characterizing the earlier stages of somatosensory pathways. In this study, we developed a novel methodology to visualize individual neurons within the trigeminal ganglion-a crucial cluster of cell bodies of sensory neurons innervating the face. Our investigations revealed a reliable sensory response to stimulation of the lower incisor or lip within this ganglion. The responsive neurons were confined to a specific portion of the trigeminal ganglion, consistent with innervation of the lower oral cavity by the mandibular nerve (V3). Contrary to our expectations, we did not observe a discernible map differentiating the lower tooth and the lip. Instead, the spatial representation of the tooth and lip within this portion of trigeminal ganglion exhibited intermingling with no clear border between tooth-responding and lip-responding neurons. These findings contrast with earlier studies that identified tooth and lip responding regions in the somatosensory cortex. Our study sheds light on the complex spatial organization of sensory processing in the trigeminal system, highlighting the need for further research to elucidate the underlying mechanisms and implications for sensory perception and clinical interventions.
躯体定位是感觉信息处理的一项基本原则，传统上在大脑皮层的研究中受到重视。然而，人们在揭示体感通路早期阶段的空间组织方面投入的精力很少。在本研究中，我们开发了一种新颖的方法来可视化三叉神经节内的单个神经元——三叉神经节是支配面部的感觉神经元细胞体的关键集群。我们的研究揭示了该神经节内对下切牙或嘴唇刺激的可靠感觉反应。反应性神经元局限于三叉神经节的特定部分，这与下颌神经（V3）对下口腔的支配一致。与我们的预期相反，我们没有观察到区分下牙和嘴唇的可辨别的图谱。相反，在三叉神经节的这一部分中，牙齿和嘴唇的空间表征呈现出相互交织的状态，对牙齿有反应和对嘴唇有反应的神经元之间没有明显的边界。这些发现与早期在体感皮层中确定牙齿和嘴唇反应区域的研究形成对比。我们的研究揭示了三叉神经系统中感觉处理的复杂空间组织，强调需要进一步研究以阐明其潜在机制以及对感觉感知和临床干预的影响。
