A Laser Diode-Based Wireless Optogenetic Headstage

A power efficient, battery powered optogenetic headstage for doing in-vivo experiments with freely moving genetically modified animals is presented. The proposed system is designed with commercial off-the-shelf components, and is based on a Bluetooth Low Energy (BLE) System-on-Chip (SoC) with an integrated antenna and a programmable ARM Cortex-M3 microprocessor core able to control the circuit. The optical signal is generated using a compact laser diode (LD) suitable for a wearable headstage. LD produces light in a highly concentrated way considerably improving the LD-optical fiber coupling efficiency. The proposed optogenetic system is shown to provide 120 mW/mm
²
at the fiber tip with a current consumption of 60mA, considerably lower than LED-based systems. The system is remotely controlled by a smartphone app where the user can define optical stimulations patterns settings (optical power, frequency, duty cycle, etc.). It is also powerful enough to be ready to house additional optogenetics functionalities, like electrochemical sensing of the cell response, without significant modifications, thus being the basis of an integrated optogenetic platform.