Olfactory Glomerular Module
It is attractive model to consider the brain function is based on multiple network units, such as column in visual system, barrel in somatosensory system and glomerulus module in the olfactory system. These network units are adequate size to examine the multiple hypotheses, which can bridge the functions of individual neuron and their embedding network. Especially, we are interested in whether the network unit is organized in the cell type specific manner. Using conventional in vivo functional two-photon microscopy and electrophysiology, we identify each component neurons and measure the physiological and odorant response properties in the mouse olfactory glomerular module.
Temporal Dynamics of the Neuronal Network
The drawback of the conventional functional two-photon microscopy is its slow temporal resolution (several Hz). We overcome the problem using recently developed Acousto-Optic Deflector (AOD) two-photon imaging system. This system makes it possible to measure the multiple neuronal activities with sub-millisecond temporal resolution. Using the system, we challenge to gain the new insight of the temporal organization of the neuronal ensemble activity, such as synchrony and asynchrony of a given cell types within or between the glomerular modules.
Large Scale Network Connectivity
Brain road map is essential to understand the information flow between spatially segregated brain areas. In the olfactory system, it is still unclear whether there is a rule, which organizes the connection from olfactory bulb to the higher brain center, or vise versa. Using fluorescence micro-optical sectioning tomography, we challenge to explore the rule and clarify the large-scale connectivity for olfaction. This system makes possible to trace the individual neuronal axons with high contrast image quality. We hope this project will navigate next stage of olfactory research.