Development of transition of neural circuit for behavioral adaptation

Hiromu Yawo (Tohoku University)

“Quantitative connectomics of the network reorganization during development”

During development of the central and peripheral nervous systems, the axons of presynaptic neurons innervate the target tissue to make connections with the postsynaptic cells. Initially, a presynaptic axon branch frequently to contact with many postsynaptic cells and a postsynaptic cell is innervated with many presynaptic axons. However, the massively reorganization follows in their connection to form mature neuronal circuit. As a result, some of presynaptic neurons lose their connections once made on a postsynaptic target cell. This process of synapse elimination is prevalent among central and peripheral nervous system to optimize the flow of information in terms of convergence. On the other hand, the transiently expanded axon arborization of a presynaptic neuron contracts by losing their aberrant connections to be adjusted to the appropriate number of postsynaptic cells during a certain critical period of the development. This process of axon pruning is also prevalent among central and peripheral nervous system to optimize the flow of information in terms of divergence.

In our present study we are aiming to investigate the development of axonal projection in the ciliary ganglion (CG) of chick embryo as a model system of network reorganization (Egawa et al., 2013). The connectomics of a presynaptic axon will be quantitatively performed using the sparse gene expression system, the tissue clearing and the 3D-image analysis in combination. Our chick CG network, with its simple organization and ease of gene manipulation using in ovo electroporation technique, should become an ideal model system for finding the fundamental rules of network reorganization and for unveiling the molecular mechanisms underlying these rules.

 

 
Recent Publications
1. Yawo, H., Kandori, H. & Koizumi, A. (editors) “Optogenetics: Light-Sensing Proteins and Their Applications”, Springer, Tokyo (2015). [Book]
2. Yawo, H., et al. (2013) Optogenetic manipulation of neural and non-neural functions. Growth Differ. 55(4):474-490. [Review]
3. Egawa, R., et al. (2013) Optogenetic probing and manipulation of the calyx-type presynaptic terminal in the embryonic chick ciliary ganglion. PLoS One 8, e59179.

Posted:2016/03/10