CICLoPS Photometry Project
Open source in-vivo fiber photometry for low-light level recordings
Background
Fiber photometry is a tool used in neuroscience to optically monitor neural correlates of behavior to targeted neuronal populations in the brain. When applied to study neurons genetically-targeted to express optical reporters of local physiological dynamics, the experimentalist gains access to real-time activity of arbitrary neuronal populations during behavioral assays.
The technology surrounding photometry has matured rapidly, and multiple systems have been reported and several solutions are now commercially available. However, mainstream technologies have limitations, of which poor sensitivity to fluorescence is a notable challenge. This problem is compensated in experiments by increasing the level of input excitation light. However, this causes increased destruction of the fluorescent proteins, which results in a reduction in overall brightness, and largely restricts studies to short-term transients, precluding longer-term and repeated investigations into optically-reported neuronal activity. The Integrated Circuits and Optical Imaging Laboratory at the University of Calgary developed a high-performance, cost-effective system for deep-brain optical measurements of fluorescence intensity transients in freely-moving animals that achieves excellent Signal-to-noise ratio at extremely low levels of input excitation light. The system is named CICLoPS for Cost-effective, In-Vivo, Customizeable, Low-Power, Photometry System.
Components
CICLoPS is a complete solution for in-vivo fiber photometry, designed specifically to monitor neural activity with low-light levels. The Construction and Assembly Guide for the core system refers to source files in the optical system, coherent detection hardware, and code for data acquisition. Instructions on how to achieve additional functions are also provided.
Related Work
This development builds on the prior contributions from several others, listed below.
[1] Grienberger, Christine, et al. "Sound‐evoked network calcium transients in mouse auditory cortex in vivo." The Journal of physiology 590.4 (2012): 899-918.
[2] Cui, Guohong, et al. "Deep brain optical measurements of cell type–specific neural activity in behaving mice." Nature protocols 9.6 (2014): 1213.
[3] Gunaydin, Lisa A., et al. "Natural neural projection dynamics underlying social behavior." Cell 157.7 (2014): 1535-1551.
[4] LeChasseur, Yoan, et al. "A microprobe for parallel optical and electrical recordings from single neurons in vivo." Nature methods 8.4 (2011): 319-325.
[5] Lerner, Talia N., et al. "Intact-brain analyses reveal distinct information carried by SNc dopamine subcircuits." Cell 162.3 (2015): 635-647.
[6] Kim, Christina K., et al. "Simultaneous fast measurement of circuit dynamics at multiple sites across the mammalian brain." Nature 201 (2016): 6.
[7] Pashaie, Ramin, and Ryan Falk. "Single optical fiber probe for fluorescence detection and optogenetic stimulation." IEEE Transactions on Biomedical Engineering 60.2 (2013): 268-280.
[8] Doronina‐Amitonova, Lyubov V., et al. "Fiber‐optic probes for in vivo depth‐resolved neuron‐activity mapping." Journal of biophotonics 3.10‐11 (2010): 660-669.
[9] Guo, Qingchun, et al. "Multi-channel fiber photometry for population neuronal activity recording." Biomedical optics express 6.10 (2015): 3919-3931.