title: In vivo two-photon imaging of mouse hippocampal neurons in dentate gyrus using a light source based on a high-peak power gain-switched laser diode.
abstract: In vivo two-photon microscopy is an advantageous technique for observing the mouse brain at high resolution. In this study, we developed a two-photon microscopy method that uses a 1064-nm gain-switched laser diode-based light source with average power above 4 W, pulse width of 7.5-picosecond, repetition rate of 10-MHz, and a high-sensitivity photomultiplier tube. Using this newly developed two-photon microscope for in vivo imaging, we were able to successfully image hippocampal neurons in the dentate gyrus and obtain panoramic views of CA1 pyramidal neurons and cerebral cortex, regardless of age of the mouse. Fine dendrites in hippocampal CA1 could be imaged with a high peak-signal-to-background ratio that could not be achieved by titanium sapphire laser excitation. Finally, our system achieved multicolor imaging with neurons and blood vessels in the hippocampal region in vivo. These results indicate that our two-photon microscopy system is suitable for investigations of various neural functions, including the morphological changes undergone by neurons during physiological phenomena.
authors: Research Institute for Electronic Science, Hokkaido University, Kita 20 Nishi 10, Kita-ku, Sapporo, 001-0020, Japan ; Graduate school of information science and technology, Hokkaido University, Kita 20 Nishi 10, Kita-ku, Sapporo, 001-0020, Japan ; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo, Japan ; These authors contributed equally to this work.
authors: Ryosuke
authors: R
authors: Kawakami
authors: Research Institute for Electronic Science, Hokkaido University, Kita 20 Nishi 10, Kita-ku, Sapporo, 001-0020, Japan ; Graduate school of information science and technology, Hokkaido University, Kita 20 Nishi 10, Kita-ku, Sapporo, 001-0020, Japan ; These authors contributed equally to this work.
authors: Kazuaki
authors: K
authors: Sawada
authors: New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10 Aramaki-Aoba, Aoba-ku, Sendai, 980-8579, Japan.
authors: Yuta
authors: Y
authors: Kusama
authors: New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10 Aramaki-Aoba, Aoba-ku, Sendai, 980-8579, Japan.
authors: Yi-Cheng
authors: YC
authors: Fang
authors: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1,Aoba-ku, Sendai, 980-8577, Japan.
authors: Shinya
authors: S
authors: Kanazawa
authors: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1,Aoba-ku, Sendai, 980-8577, Japan ; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo, Japan.
authors: Yuichi
authors: Y
authors: Kozawa
authors: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1,Aoba-ku, Sendai, 980-8577, Japan ; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo, Japan.
authors: Shunichi
authors: S
authors: Sato
authors: New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10 Aramaki-Aoba, Aoba-ku, Sendai, 980-8579, Japan ; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo, Japan.
authors: Hiroyuki
authors: H
authors: Yokoyama
authors: Research Institute for Electronic Science, Hokkaido University, Kita 20 Nishi 10, Kita-ku, Sapporo, 001-0020, Japan ; Graduate school of information science and technology, Hokkaido University, Kita 20 Nishi 10, Kita-ku, Sapporo, 001-0020, Japan ; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo, Japan.
authors: Tomomi
authors: T
authors: Nemoto
keywords: (110.6880) Three-dimensional image acquisition; (180.0180) Microscopy; (180.2520) Fluorescence microscopy; (180.4315) Nonlinear microscopy