Development of a Dual-Wavelength Isosbestic Wireless Fiber Photometry Platform for Live Animals Studies

Measuring neural activity from well-defined neural populations deep inside the brain has an important value in neuroscience. Fiber photometry is an important technique for evaluating neuron activity inside the brain. Besides, miniature wireless systems to record neuronal activity in a fully untethered experimental setting have recently become extremely interesting for experimenters. Still, a noise-robust wireless fiber photometry system for this purpose does not exist. Using an isosbestic excitation wavelength for recording with GCaMP6 has recently been suggested to reduce the different types of noises. We present the design of a wireless fiber photometry system at 470 nm for calcium-dependent fluorescence emission of GCaMP6 using a calcium-independent isosbestic excitation wavelength of 410 nm. Synthetic emission fluorescence light was played from a function generator to drive an LED at 530 nm at test the photometry platform. The setup has been fixed at 4.18 mW light power after linearity assessment while the analog circuit has THD of 0.35%. Then, the recorded synthetic neuronal activity was transmitted wirelessly to the base station. Finally, the isosbestic response has been aligned and removed from the calcium-dependent fluorescence signal to have a noiseless neuronal activity.