A Multichannel Recording System with Optical Stimulation for Closed-Loop Optogenetic Experiments
Selective perturbation of the activity of specific cell types in the brain tissue is essential in understanding the function of neuronal circuits involved in cognition and behavior and might also provide therapeutic neuromodulation strategies. Such selective neuronal addressing can be achieved through the optical activation of light-sensitive proteins called opsins that are expressed in specific cell populations through genetic methods—hence the name “optogenetics.” In optogenetic experiments, the electrical activity of the targeted cell populations is optically triggered and monitored using arrays of microelectrodes. In closed-loop studies, the optical stimulation parameters are adjusted based on the recorded activity, ideally in real time. Here we describe the basic tools and the protocols allowing closed-loop optogenic experiments in vivo.
Key wordsOptical stimulation Closed-loop Multichannel recordings Tetrode Optic fibers Spike-sorting
The authors thank Prof. Veerle Baekelandt and Dr. Chris Van den Haute for providing the viral vectors used in this work. We thank Mr. Valentijn Tuts for helping with the PCB assembly and custom cables. We thank Dr. Fabian Kloosterman at NERF for assistance and suggestions on the design of the tetrode micro-drive.
These methods and protocols have been developed within the frame of the FP7 EC project ENLIGHTENMENT. The project ENLIGHTENMENT acknowledges the financial support of the Future and Emerging Technologies (FET) programme within the Seventh Framework Programme for Research of the European Commission
- 2.Knopfel T, Boyden ES (2012) Optogenetics: tools for controlling and monitoring neuronal activity. Prog Brain Res 196:2–278Google Scholar
- 3.Kloosterman F, Davidson TJ, Gomperts SN, Layton SP, Hale G, Nguyen DP, Wilson MA (2009) Micro-drive array for chronic in vivo recording: drive fabrication. J Vis Exp (26):e1094. doi:10.3791/1094Google Scholar
- 21.Guger C, Gener T, Pennartz CMA, Brotons-Mas JR, Edlinger G, Bermúdez i Badia S, Verschure P, Schaffelhofer S, Sanchez-Vives MV (2011) Real-time position reconstruction with hippocampal place cells. Front Neuroprosthetics 5:85Google Scholar
- 23.Wang L, Nguyen TK, Cabral H, Gysbrechts B, Battaglia FP, Bartic C (2014) Closed-loop optical stimulation and recording system with GPU-based real-time spike sorting. In: Popp J, Tuchin V, Matthews D, Pavone F (eds) Biophotonics: photonic solutions for better health care IV: vol. 9129 (91293U-1)Google Scholar
- 24.Nguyen DP, Layton SP, Hale G, Gomperts SN, Davidson TJ, Kloosterman F, Wilson MA (2009) Micro-drive array for chronic in vivo recording: tetrode assembly. J Vis Exp 26:pii: 1098Google Scholar