Development of High-speed Laser Scanning Microscope for In Vivo Deep Brain
Imaging
Sponsored by the Shun Hing Institute of Advanced Engineering
Principal Investigator:
Professor Shih-Chi Chen, Department of Mechanical and Automation Engineering
Co-Investigators:
Prof. Wing Ho Yung, School of Biomedical Sciences
Project Team:
-
Dr. Chenglin Gu, PhD
-
Mr.
Danny Chan, PhD Candidate
Introduction
This work aims to develop new imaging
techniques, including tunable frame rate (30 - 17,280 fps) and omnidirectional
imaging, for a custom-designed laser scanning confocal and two-photon excitation
(TPE) microscope. The new functions will be used for in vivo deep brain imaging
on mice. Current microscopes typically run at a fixed frame rate with a flat
imaging plane. However, all biological subjects are “3-dimensional (3-D)” in
nature and various biological events, e.g. blood flow or neuron signaling, occur
at different time scales. Accordingly, a versatile microscope with capabilities
of frame-rate tuning and a 3-D programmable imaging plane is highly desirable.
The frame-rate tuning function can be achieved by a new synchronization circuit
and related software development. It is worth to note that ultra-high frame
rates, i.e. 1000 - 10,000 fps, are achieved by trading off the imaging area, and
thus at any frame rate, the “pixel dwell time” of the system remains constant,
keeping a low signal-to-noise ratio. 3-D programmable imaging plane is achieved
by the introduction of a high-speed piezoelectric objective scanner. During the
in-plane raster scan procedure, the objective lens can be moved to any arbitrary
position in the Z axis, thus enabling the “omnidirectional scan”.
These new functions will be used to
investigate deep regions in brain in vivo and enable many new studies that
cannot be realized in the past. Specifically, we will follow neuron axons (not
in the same plane) in a mouse brain and identify their related neural circuits
and simultaneously observe their signaling processes at 1000 fps. We will
perform deep brain calcium imaging of visual and motor cortical columns (~800µm
deep) and record from multiple hypercolumns in a single scan. Lastly, we will
study and image dendritic spines and track the formation and disappearance of
individual spines. These results will generate significant impact by elucidating
the learning processes involved in visuomotor tasks.
Publications
TBA
References
[1]
D. Zhang, J. Cheng, and S. Chen, “Multi-depth Real-time Confocal Imaging,”
Proceedings of the 2013 International Symposium on Optomechatronic Technologies
(ISOT), Jeju, Korea, Oct. 28-30, 2013 (Best Paper Award).
[2] J. B. Pawley, ed.,
Handbook of Biological Confocal Microscopy,
3rd Ed. Springer, 2006.