Imagine that you smell some delicious foods as you walk down a street – and suddenly you start to recall the good old days you had that dish when you were small. This is a typical example showing the powerful link between memory and olfaction – the sense of smell. But how do neuronal circuits in your brain enable that? And why do we have to lose such a precious memory when we get old?

My lab is investigating circuit mechanism of sensory perception and memory, using rodents as model organisms. We are also clarifying what neural circuits are affected and how the impairments of neuronal activities cause memory loss in Alzheimer’s disease.

Memory, olfaction, Alzheimer's disease, hippocampus, entorhinal cortex, electrophysiology

Publications

Impaired In Vivo Gamma Oscillations in the Medial Entorhinal Cortex of Knock-in Alzheimer Model
Nakazono T, Lam TN, Patel AY, Kitazawa M, Saito T, Saido TC, Igarashi KM*
Front Syst Neurosci,  11:48 (2017)

Entorhinal map of space
Igarashi KM* (*Corresponding author)
Brain Research,  1637:177-187 (2016)

Topography of Place Maps along the CA3-to-CA2 Axis of the Hippocampus.
Lu L, Igarashi KM, Witter MP, Moser EI, Moser MB.
Neuron. 87:1078-92 (2015)

Plasticity in oscillatory coupling between hippocampus and cortex
Igarashi KM* (*Corresponding author)
Curr Opin Neurobiol. 35:163-168 (2015)

Coordination of entorhinal-hippocampal ensemble activity during associative learning.
Igarashi KM*, Lu L, Colgin LL, Moser MB, Moser EI* (*Co-corresponding authors)
Nature. 510: 143-7 (2014)

Functional diversity along the transverse axis of hippocampal area CA1.
Igarashi KM*, Ito HT, Moser EI, Moser, M-B. (*Corresponding author)
FEBS Lett. 588:2470-2476 (2014)

Parallel mitral and tufted cell pathways route distinct odor information to different targets in the olfactory cortex.
Igarashi KM*, Ieki N, An M, Yamaguchi Y, Nagayama S, Kobayakawa K, Kobayakawa R, Tanifuji M, Sakano H, Chen WR, Mori K*  (*Co-corresponding authors)
Journal of Neuroscience. 32:7970-85 (2012)

Genetic visualization of the secondary olfactory pathway in Tbx21 transgenic mice.
Mitsui S, Igarashi KM, Mori K and Yoshihara Y
Neural Systems & Circuits. 1:5 (2011)

Swept source optical coherence tomography as a tool for real time visualization and localization of electrodes used in electrophysiological studies of brain in vivo.
Watanabe H, Rajagopalan UM, Nakamichi Y, Igarashi KM, Kadono H, Tanifuji M.
Biomedical Optics Express. 2:3129-3134 (2011)

In vivo layer visualization of rat olfactory bulb by a swept source optical coherence tomography and its confirmation through electrocoagulation and anatomy.
Watanabe H, Rajagopalan UM, Nakamichi Y, Igarashi KM, Madjarova VD, Kadono H, Tanifuji M.
Biomedical Optics Express. 2:2279-2287 (2011)

Two highly homologous mouse odorant receptors encoded by tandemly-linked MOR29A and MOR29B genes respond differently to phenyl ethers.Tsuboi A, Imai T, Kato HK, Matsumoto H, Igarashi KM, Suzuki M, Mori K, Sakano H.
European Journal of Neuroscience. 33:205-13 (2011)

Differential axonal projection of mitral and tufted cells in the mouse main olfactory system.
Nagayama S, Enerva A, Fletcher ML, Masurkar AV, Igarashi KM, Mori K, Chen WR.
Frontiers in Neural Circuits. 4. Pii120 (2010)

Dendrodendritic synapses and functional compartmentalization in the olfactory bulb.
Mori K, Matsumoto H, Tsuno Y, Igarashi KM.
Ann N Y Acad Sci. 1070:255-258 (2009)

Maps of odorant molecular features in the Mammalian olfactory bulb.
Mori K, Takahashi YK, Igarashi KM, Yamaguchi M.
Physiol Rev.　86:409-433 (2006)

Spatial representation of hydrocarbon odorants in the ventrolateral zones of the rat olfactory bulb.
Igarashi KM, Mori K.
Journal of Neurophysiology. 93:1007-1019 (2005)

Odor Maps in the Dorsal and Lateral Surfaces of the Rat Olfactory Bulb.
Mori K, Takahashi YK, Igarashi K, and Nagayama S
Chemical Senses. 30:i103-i104 (2005)