A Closed-Loop Optogenetic Stimulation Device

Epsy S Edward,Abbas Z Kouzani

doi:10.3390/electronics9010096

Abstract

Closed-loop optogenetic stimulation devices deliver optical stimulations based on real-time measurement and analysis of neural responses to stimulations. However, the use of large bench-top and tethered devices hinders the naturalistic test environment, which is crucial in pre-clinical neuroscience studies involving small rodent subjects. This paper presents a tetherless, lightweight and miniaturized head-mountable closed-loop optogenetic stimulation device. The device consists of three hardware modules: a hybrid electrode, an action potential detector, and an optogenetic stimulator. In addition, the device includes three software modules: a feature extractor, a control algorithm, and a pulse generator. The details of the design, implementation, and bench-testing of the device are presented. Furthermore, an in vitro test environment is formed using synthetic neural signals, wherein the device is validated for its closed-loop performance. During the in vitro validation, the device was able to identify abnormal neural signals, and trigger optical stimulation. On the other hand, it was able to also distinguish normal neural signals and inhibit optical stimulation. The overall power consumption of the device is 24 mW. The device measures 6 mm in radius and weighs 0.44 g excluding the power source.

Highlights

Neuroscientists required a technology to selectively excite or inhibit neural structures of the brain.They used electrical deep brain stimulation to modulate target brain regions [1]
The results Results matched the theoretical estimation of gain and cut-off frequency of Action potential detector (APD), see
The APD output waveform verified the theoretical estimates of amplification and filtration

Summary

Introduction

Neuroscientists required a technology to selectively excite or inhibit neural structures of the brain They used electrical deep brain stimulation to modulate target brain regions [1]. Optogenetics is a stimulation technique that uses light to control the neural activity of the brain [4] In this method, the target neurons are transfected with microbial opsins that are sensitive to light. Closed-loop optogenetic stimulation (CLOS), on the other hand, modulates the neurons based on real-time measurement and analysis of neural responses. This approach enhances the efficacy of neuromodulation [6] and is being explored as an option for investigating neuropsychiatric disorders [7], for pre-clinical studies involving small animals

Results

Discussion

Conclusion