Towards Developing a Closed-Loop System to Optogenetically Perturb Cerebellar Purkinje Cells and Assess Effects on Locomotion in Freely-Moving Mice

Abstract

The cerebellum has long been identified as a brain region involved in motor control and balance. Previously, it had been challenging to study cerebellar control of motor coordination in a context that did not involve constant user input, but recent advances in computer vision and optogenetics provide accurate monitoring of behavior and specificity of neuronal manipulation to address this problem. Given that optogenetic techniques are commonly used for probing cerebellar neurons, voluntary locomotion in control mice in an open field was compared with locomotion affected by optogenetic perturbation of Purkinje cells in experimental mice so as to assess if Purkinje cell stimulation significantly alters locomotion. The experimental set-up involved using Social LEAP Estimates Animal Pose (SLEAP), a pose estimation tool, in conjunction with DeepLabStream, an analytical framework that allows for real-time behavior-based manipulation of neuronal activity. Experimental mice were given 150 ms pulse optogenetic stimulation to ensure a behavioral response, and a short 15 ms pulse optogenetic stimulation during locomotion in an open-field as a mode of brief stimulation. Mice that had undergone optogenetic stimulation experienced a significant disturbance in phase of the step cycle, such that the trajectories of the four paws were no longer characterized as an n-dimensional oscillator. The use of DeepLabStream with SLEAP proves promising towards the development of a closed-loop system that would enable a more efficient way of probing the perturbation of Purkinje cells via optogenetic stimulation.