A micro-LED implant and technique for optogenetic stimulation of the rat spinal cord

To date, relatively few studies have used optogenetic stimulation to address basic science and therapeutic questions within the spinal cord. Even less have reported optogenetic stimulation in the rat spinal cord. This is likely due to a lack of accessible optogenetic implants. The development of a device that can be fabricated and operated by most laboratories, requiring no special equipment, would allow investigators to begin dissecting the functions of specific neuronal cell-types and circuitry within the spinal cord, as well as investigate therapies for spinal ailments like spinal cord injury. Here, we describe a long-term implantable μLED device designed for optogenetic stimulation of the spinal cord in awake, freely moving rats that is simple enough to be fabricated, implanted and operated by most laboratories. This device, which sits above the dorsal cord, can induce robust movements for at least 6 weeks without causing physical or thermal damage to the underlying spinal cord. In this regard, the presented μLED device could help tease apart the complexities of the spinal cord and uncover potential future therapeutics.