Interdisciplinary Initiatives Program Round 7 - 2014

Ada Poon, Electrical Engineering
Scott Delp, Bioengineering, Mechanical Engineering
David Clark, Anesthesia

This project will produce a fully-internalized, wirelessly-powered optogenetic device to chronically and controllably perturb neuronal circuits involved in the perception of pain. Pain is an enormous healthcare problem. Unfortunately, intense basic research efforts have not yet translated into clinical breakthroughs. Our limited knowledge of how specific pain signaling pathways affect behavior is the major obstacle to the design of better treatments. The rise of optogenetics within neuroscience has enabled unprecedented levels of direct control over the activity of specific neuronal populations. Initially restricted to the central nervous system, optogenetics has recently been extended to control individual types of pain-related peripheral sensory neurons. This allows, in principle, the deciphering of how specific pain circuits influence complex behaviors without using highly artificial non-specific stimuli. In current systems, however, the need for tethered fiber cables or bulky external light sources constrain opportunities for studies of pain in freely moving and socially interacting animals; understanding pain, a multidimensional subjective sensation, requires an understanding of its impact on activity patterns and social interactions. Therefore, there is much interest in developing models of pain that feature animals freely interacting with their environment. The goal of this project is to design and build a wireless optogenetics system that allows for the discovery of the relationships between the activation of specific pain fibers and animal behaviors in naturalistic environments, without constraints on animal location/interaction or requiring high levels of researcher intervention. The system will involve the creation of unprecedentedly small remotely powered and controlled light-emitting devices where most of the electronic components – including multi-wavelength LED drivers, oscillator, memory, bidirectional wireless transceiver, rectifier, and power conversion circuitry – are integrated on a tiny microchip. The remote energy source is coupled to these devices in test animals via a cavity generating radiofrequency energy positioned below the test environment. The devices will be powered no matter where they roam – no attached electronics or fiber optics is needed. The proposed system will provide an entirely novel method to control and assess the behavioral impacts of pain. This could usher in a new era of wireless optogenetics leading to a detailed understanding of how sensory input impacts key social and exploratory behaviors over long time courses.