科技部新聞稿

「看見」果蠅的思想-

以光學顯微鏡成像技術探究大腦的奧秘

日期：109年3月11日

發稿單位：生命科學研究發展司

聯絡人：李慧欣博士

電話：02-2737-7461

E-mail：hhlee@nstc.gov.tw

大腦是由成千上萬個神經細胞集合而成，是動物體中最重要的器官，但這些神經細胞是如何藉由彼此間的連結與交互作用，產生思考決策等高階功能，科學家絞盡腦汁還是沒有找到答案。

在科技部「以疾病為導向之腦與心智科學專案研究計畫」(106-108)及「台灣腦科技發展及國際躍升計畫」(108-110)的支持下，臺大物理系朱士維教授成立跨領域團隊，結合清大電機系李夢麟教授與楊尚達教授、清大工程與系統科學系吳順吉副教授、交大光電學院詹明哲副教授，以及捷絡生物科技股份有限公司林彥穎執行長，共同研發「新穎光學顯微鏡成像技術平台」。具有高速、高空間解析度，能觀察到果蠅腦中單一神經細胞的電生理動態行為。藉由研究與人腦神經網路運作機制類似的果蠅，以探究人腦的奧秘。相關創新成果包括：

1. < >High-speed volumetric imaging system），相關成果於去年發表在光學重要期刊Optics Letters 44, 3190-3193 (2019)，並獲選為必讀文章（參考資料1）；< > (all-optical physiology)，成功解析果蠅腦中的視覺神經迴路上下游的神經連結與編碼模式，以瞭解腦神經的運作，相關成果於去年發表在iScience 22, 133-146 (2019)（參考資料2）；< >(COOL, Confocal lOcalization deep-imaging with Optical cLearing)，結合螢光蛋白標定、共軛焦掃描顯微鏡、光學組織澄清技術以及定位顯微技術等先進科技，以非侵入方式、20奈米空間解析度分辨出果蠅全腦中相鄰或彼此纏繞糾結之神經纖維分佈，找出其連結點所在，藉以判斷神經連結路徑，相關成果於去年發表在iScience 14, 164-170 (2019)（參考資料3）。朱教授更因相關研究貢獻，受光學領域頂尖期刊Light: Science and Applications (IF > 14) 邀請撰寫介紹文章，提升臺灣學術能見度（參考資料4）。< >1釐米的「雙光子影像系統」無法在果蠅腦中成像的主因，可能是其氣管結構所造成的像差，朱教授團隊更是世界上第一個完成此像差的組織光學衰減定量，並證明使用「長波長三光子螢光」即可改善影像，有機會進行果蠅活體全腦觀察，相關成果於去年發表在Biomedical Optics Express 10, 1627-1637 (2019)（參考資料5）。

   K.-J. Hsu, Y.-Y. Lin, Y.-Y. Lin, K. Su, K.-L. Feng, S.-C. Wu, Y.-C. Lin, A.-S. Chiang, S.-W. Chu*, “Millisecond two-photon optical ribbon imaging for small-animal functional connectome study” Opt. Lett. 44, 3190-3193 (2019). Editor’s pick https://doi.org/10.1364/OL.44.003190

2. C. Huang, C.-Y. Tai, K.-P. Yang, W.-K. Chang, K.-J. Hsu, C.-C. Hsiao, S.-C. Wu, Y.-Y. Lin*, A.-S. Chiang*, and S.-W. Chu*, “All-optical volumetric physiology for connectomics in dense neuronal structures” iScience 22, 133-146 (2019) https://doi.org/10.1016/j.isci.2019.11.011

3. H.-Y. Lin, L.-A. Chu, H. Yang, K.-J. Hsu, Y.-Y. Lin, K.-H. Lin, S.-W. Chu*, iScience 14, 164-170 (2019). https://doi.org/10.1016/j.isci.2019.03.025

4. S.-W. Chu “Optical microscopy approaches angstrom precision, in 3D!”, Light Sci. Appl. 8, 117 (2019) Invited News and Views article

   https://doi.org/10.1038/s41377-019-0226-y

5. K.-J. Hsu, Y.-Y. Lin, A.-S. Chiang, S.-W. Chu*, “Optical properties of 1627-1637 (2019). https://doi.org/10.1364/BOE.10.001627

研究成果聯絡人

朱士維教授

國立臺灣大學物理學系

聯絡電話(公)：02-33665131

電子郵件信箱：swchu@ntu.edu.tw

Press Release

March 11th, 2020

Visualization of Drosophila’s mind

- Developing novel optical microscopies to unravel the mystery of brain function

Brain, which governs our mind and behaviors, is arguably the most important organ in our body, but is also the functionally least understood one. Although the function of a single neuron or interaction of a few neurons have been well studied, the number of neurons ranges from hundred thousands in drosophila to billions in human brains, and the emerging properties from the massive connection among these neurons are unknown yet. The main obstacle is lacking a suitable tool that allows us to observe the physiological dynamics of brain with enough spatiotemporal resolution.

Under the support of the “Disease-oriented Brain and Mind Research Program” (2016 – 2019) and “Taiwan Brain Technology Development and International Raising Program” (2019 – 2021) (MOST, R.O.C.), Prof. Shi-Wei Chu (Physics, NTU) established an interdisciplinary team, including Prof. Meng-Lin Li (EE, NTHU), Prof. Shang-Da Yang (EE, NTHU), Prof. Shun-Chi Wu (Engineering and System Science, NTHU), Prof. Ming-Che Chan (Photonics, NCTU), and Dr. Yen-Yin Lin (JelloX Co.), to develop novel optical micro-imaging platform to study Drosophila brain, whose neural network connection is similar to human brain. The platform features high temporal and spatial resolutions that are capable to capture physiological dynamics of neurons in an intact living Drosophila brain. Our technical innovations are:

1. First high-speed volumetric imaging system that provides millisecond temporal resolution to observe 3D neuronal firing dynamics in a living Drosophila brain. The result was published in a leading optics journal from Optical Society of America, Optics Letters，and was selected as “Editor’s pick”. (reference 1)

2. Combining the high-speed volumetric imaging system with a home-built optical neuronal stimulation system, we have achieved volumetric all-optical physiology observation, that allows us to resolve the 3D neural connection and coding of visual circuits in a Drosophila brain. The result was published in a new interdisciplinary journal of Cell Press, iScience, in 2019. (reference 2)

3. We have developed deep-tissue super-solution imaging (COOL, Confocal lOcalization deep-imaging with Optical cLearing), which combines advanced techniques of fluorescence protein labeling, confocal scanning microscopy, optical clearing, and localization microscopy to achieve 20-nm spatial resolution across a whole brain of Drosophila. Together these techniques are readily available for many biologists without the need of upgrading hardware, and provide unprecedented depth/resolution performance to three-dimensionally resolve densely entangled dendritic fibers from top to bottom in a complete Drosophila brain. The method not only paves the way toward whole-brain neural network studies, but also will be applicable to other high-resolution imaging in biological tissues. This was published in iScience 2019 (reference 3). Due to the contribution in the field of super-resolution microscopy, Prof. SW Chu was invited to write a News and Views article in a top optics journal, Light: Science and Applications (IF > 14), promoting the visibility of Taiwan academic society. (reference 4)

4. We also explained a mystery that a deep-tissue imaging technique, two-photon microscopy, which typically provides 1 mm penetration depth in mouse brain, cannot penetrate more than 0.1 mm in Drosophila’s brain. The reason is optical aberration due to air in trachea of insect’s brain (mouse has blood in vessel, whose refractive index is similar to that of brain tissues). Surprisingly, no study has reported optical properties of trachea-filled tissues. We are not only the first group that quantify the optical decay in trachea-filled Drosophila’s brain, but we also demonstrate that using long-wavelength three-photon microscopy enables whole-brain imaging in a living Drosophila. This was published in another leading optics journal from Optical Society of America, Biomedical Optics Express, in 2019. (reference 5)

Currently the whole research team is devoted to develop novel optical techniques under the support of the “Taiwan Brain Technology Development and International Raising Program” (2019 – 2021) (MOST, R.O.C.). In addition, we work closely with MOST- and MoE-funded NTHU “Brain Research Center” (2018-2023), which was led by Academician Ann-Shyn Chiang (Systems Neuroscience, NTHU). Our future goal is to realize observation of “functional whole-brain connectome” in Drosophila, i.e. the connections among every single neuron during learning and memory formation, with high temporal resolution (millisecond), high spatial resolution (sub-micrometer to nanometer), and high penetration depth (millimeter), to unravel the mysteries of brain function.

Reference:

1. K.-J. Hsu, Y.-Y. Lin, Y.-Y. Lin, K. Su, K.-L. Feng, S.-C. Wu, Y.-C. Lin, A.-S. Chiang, S.-W. Chu*, “Millisecond two-photon optical ribbon imaging for small-animal functional connectome study” Opt. Lett. 44, 3190-3193 (2019). Editor’s pick https://doi.org/10.1364/OL.44.003190

2. C. Huang, C.-Y. Tai, K.-P. Yang, W.-K. Chang, K.-J. Hsu, C.-C. Hsiao, S.-C. Wu, Y.-Y. Lin*, A.-S. Chiang*, and S.-W. Chu*, “All-optical volumetric physiology for connectomics in dense neuronal structures” iScience 22, 133-146 (2019) https://doi.org/10.1016/j.isci.2019.11.011

3. H.-Y. Lin, L.-A. Chu, H. Yang, K.-J. Hsu, Y.-Y. Lin, K.-H. Lin, S.-W. Chu*, iScience 14, 164-170 (2019). https://doi.org/10.1016/j.isci.2019.03.025

4. S.-W. Chu “Optical microscopy approaches angstrom precision, in 3D!”, Light Sci. Appl. 8, 117 (2019) Invited News and Views article

https://doi.org/10.1038/s41377-019-0226-y

1. K.-J. Hsu, Y.-Y. Lin, A.-S. Chiang, S.-W. Chu*, “Optical properties of 1627-1637 (2019). https://doi.org/10.1364/BOE.10.001627

Media Contact

Dr. Shi-Wei Chu

Department of Physics, National Taiwan University

TEL: 02-33665131

Email：swchu@phys.ntu.edu.tw

Dr. Hui-Hsin Lee

Department of Life Sciences, Ministry of Science and Technology

TEL: 02-27377461

Email: hhlee@nstc.gov.tw