2018年8月3日 加藤紘之さん(University of North Carolina Chapel Hill)セミナー

神経生理学の研究者である加藤紘之博士(ノースカロライナ大学チャペルヒル校
神経科学センター・准教授)をお招きし、セミナーを開催いたします。2光子カルシウムイメージングや光遺伝学を駆使した大脳皮質聴覚野の研究についてご講演頂きます。どなたでも参加可能です。ふるってご参加下さい。
海外留学や海外での独立のご経験についてもお話いただける予定(日本語)ですので、学部学生・大学院生の参加も歓迎します。

演者: 加藤 紘之 先生
所属: ノースカロライナ大学チャペルヒル校准教授
https://katolab-unc.org/

タイトル:
大脳皮質聴覚野における感覚チューニング
Inhibitory circuits underlying sensory tuning of cortical neurons

日時: 2018年8月3日(金)17:00~18:00
場所: 基礎研究A棟1階 第2講義室(生協前)

要旨:
Lateral inhibition is a fundamental circuit operation that sharpens
the tuning properties of cortical neurons. This operation is
classically attributed to an increase in GABAergic synaptic input
triggered by non-preferred stimuli. Here we use in vivo whole-cell
recording and two-photon Ca2+ imaging in awake mice to show that
lateral inhibition shapes frequency tuning in primary auditory cortex
via an unconventional mechanism: non-preferred tones suppress both
excitatory and inhibitory synaptic inputs onto layer 2/3 cells
(“network suppression”). Moreover, optogenetic inactivation of
inhibitory interneurons elicits a paradoxical increase in inhibitory
synaptic input. These results indicate that GABAergic interneurons
regulate cortical activity indirectly via the suppression of recurrent
excitation (inhibition-stabilized network model), rather than via the
direct inhibition. Furthermore, the network suppression underlying
lateral inhibition was blocked by inactivation of
somatostatin-expressing interneurons (SOM cells), but not
parvalbumin-expressing interneurons (PV cells). These findings reveal
that SOM cells govern lateral inhibition and control cortical
frequency tuning through the regulation of reverberating recurrent
circuits. Together with our previous finding that SOM cell activity is
regulated by the behavioral relevance attached to sounds, these
results demonstrate a dynamic nature of sensory tuning that is enabled
by cortical inhibitory circuits.

参考文献:
1. Kato HK, Asinof SK, Isaacson JS. (2017) Network-level control of
frequency tuning in auditory cortex. Neuron 95: 412-423.
2. Kato HK, Gillet SN, Isaacson JS. (2015) Flexible sensory
representations in auditory cortex driven by behavioral relevance.
Neuron 88: 1027-1039.
3. Kato HK, Gillet SN, Peters AJ, Isaacson JS, Komiyama T. (2013)
Parvalbumin-Expressing Interneurons Linearly Control Olfactory Bulb
Output. Neuron 80:1218-1231.
4. Kato HK, Chu MW, Isaacson JS, Komiyama T. (2012) Dynamic sensory
representations in the olfactory bulb: modulation by wakefulness and
experience. Neuron 76:962-75.

研究セミナーは英語での発表となりますが、日本語での質疑も歓迎です。

世話人: 医学研究院・疾患情報研究分野 今井 猛