Meeting Abstract

S2-1.5  Thursday, Jan. 3  Neuromeres segmentation and trigeminal nerve projections in the developing vertebrate brain MURAKAMI, Yasunori; Ehime University bothrops@sci.ehime-u.ac.jp

Vertebrate brains exhibit remarkable diversity in each animal group, reflecting evolutionary changes at the molecular-level developmental program of the nervous system that vertebrates have experienced. We focused on the developmental morphological plan of the brain to understand the evolutionary scenario that led to the above diversity. By comparing the organization of the brain of non-vertebrate chordates, cyclostomes and gnathostomes, a step-wise modification of brain patterning programs becomes apparent. Characteristically, neuromere compartments which give rise to specific neurons and neuronal tracts thought to have been established in the vertebrate common ancestor. Furthermore, by labeling the mouse oral region, the relationship between trigeminal somatotopy and rhombomere compartments become visible. The topographical projection of the trigeminal nerve in relation to rhombomeres was also conserved in the lamprey. Finally, by combining the knowledge on rhombomere segments and trigeminal projections, the evolutionary relationship between brain segmentation and neuronal circuits are discussed.