Fully Implantable, Wireless and Battery-Free Platforms for Mechanistic Exploration of Neural Dynamics in Small Animals

Abstract

Recent advances in soft electronics, wireless power delivery, and minimally invasive device design have enabled the creation of a new class of fully implantable, battery-free systems for neuroscience research. By eliminating external tethers and bulky power sources, these platforms allow stable, long-term operation in freely behaving animals, offering critical advantages for studying neural processes in naturalistic conditions. Reliable wireless power transfer and robust system integration ensure sustained functionality while minimizing tissue disruption, supporting chronic use in small animal models. This thesis introduces two subdermal, tether-free technologies engineered to explore and modulate neural activity in vivo. The first is a fully implantable spinal cord stimulation (SCS) system designed to investigate mechanisms of neuromodulation in chronic pain. The device supports programmable, region-specific electrical stimulation over extended periods, enabling detailed behavioral and physiological studies without direct physical interaction. Contributions to this system include in vivo validation, characterization of chronic stability, and demonstration of therapeutic efficacy in rodent pain models. The second system is a wireless, subdermal platform for real-time calcium photometry and closed-loop optogenetic stimulation. This device enables dynamic, activity-dependent intervention by recording neural signals from deep brain structures and triggering optical stimulation when defined thresholds are met. Applied in behavioral paradigms related to feeding, the platform supports causal investigations into the relationship between neural circuit activity and behavior. Custom optical filtering, circuit integration, and implantable form factor design were key to achieving signal fidelity and chronic compatibility. Together, these systems expand the experimental toolkit for circuit-level neuroscience by providing fully implantable, multimodal interfaces that support both neural recording and modulation in unrestrained animals. These contributions address major limitations of existing tethered and battery-powered approaches, advancing the field toward scalable, chronic, and behaviorally relevant neuromodulation platforms for preclinical research and future therapeutic development.