Laboratory for Sensory Circuit Formation

The mammalian nervous system is composed of enormous numbers of neurons, but how do these cells take on diverse fates and organize and array themselves during development? It has generally been thought that neuronal identities are genetically programmed, and that neuronal connectivity is maintained by molecular "lock and key" mechanisms. The mouse olfactory system, however, is highly adaptive; olfactory neuronal identities are dependent on peripheral inputs, and form the basis for a self-organizing olfactory map. Our lab is studying odorant receptor-dependent axon projection of olfactory sensory neurons and the formation of neuronal circuitry in the olfactory bulb dependent on inputs from these neurons.

Research Subjects

• Nature of the odorant receptor signaling that control the olfactory circuit formation
• Mechanisms of input-specific circuit formation in the olfactory bulb and olfactory cortex
• In vivo imaging of development and regeneration of the olfactory circuits
• Visualization and manipulation of specific neuronal circuits using novel genetic tools

Publications

1. Imai T.:
   "Positional information in neural map development: lessons from the olfactory system"
   Development, Growth & Differentiation, in press (2012)
2. Imai T & Sakano H.:
   "Axon-axon interactions in neuronal circuit assembly: lessons from olfactory map formation"
   European Journal of Neoroscience, 34, 1647-1654. (2011)
3. Tsuboi A*, Imai T*, Kato HK, Matsumoto H, Igarashi KM, Suzuki M, Mori K, Sakano H.:
   "Two highly homologous mouse odorant receptors encoded by tandemly-linked MOR29A and MOR29B genes respond differently to phenyl ethers"
   European Journal of Neoroscience, 33, 205-213. (2011)
4. Imai T, Sakano H, & Vosshall LB.:
   "Topographic Mapping-The Olfactory System"
   Cold Spring Harb Perspect Biol. 2, a001776. (2010)
5. Imai T. Yamazaki T. Kobayakawa R. Kobayakawa K. Abe T. Suzuki M. Sakano H.:
   "Pre-Target Axon Sorting Establishes the Neural Map Topography."
   Science. 325, 585-60. (2009)
6. Imai T. & Sakano H.:
   "Odorant receptor-mediated signaling in the mouse."
   Curr Opin Neurobiol. 18, 251-260. (2008)
7. Imai T. & Sakano H.:
   "Interhemispheric olfactory circuit and the memory beyond."
   Neuron 22, 465-467. (2008)
8. Kobayakawa K, Kobayakawa R, Matsumoto H, Oka Y, Imai T, Ikawa M, Okabe M, Ikeda T, Itohara S, Kikusui T, Mori K & Sakano H.:
   "Innate versus learned odour processing in the mouse olfactory bulb."
   Nature 450, 503-508. (2007)
9. Imai T. & Sakano H.:
   "Roles of odorant receptors in projecting axons in the mouse olfactory system."
   Curr Opin Neurobiol. 17, 507-15. (2007)
10. Imai T. Suzuki M. Sakano H.:
    "Odorant receptor-derived cAMP signals direct axonal targeting."
    Science. 314, 657-61. (2006)