Adam Khalifa, Martina Leistner, Jack Zhang
Implantable electrodes is a field of growing interest for neural stimulation and recording. They are highly used in the neuroscience and neuro-prosthetic applications. It is important to remember that neural codes underlying behavior cannot be explained by the responses of single cortical neurons, but instead rely on the population activity across multiple neurons. Since most neurological diseases affect multiple brain regions, being able to monitor neural activity anywhere in the brain is crucial to our understanding and treatment of dysfunction. The same is true in the neuro-prosthetic field, a large number of stimulating electrodes is needed at different locations in order to activate the brain in patterns that mimic natural activation. With recent advancements in the study of biomedical implants, several types of wirelessly powered neural interfaces have been developed, but a device than can stimulate and record neurons with arbitrary placement does not exist.
We are conducting research on implantable devices for neural stimulation and recording. Our work focuses on developing a new generation of fully implantable devices which we call the “micro-bead”. The micro-bead is an inductively powered device that is small enough (<200 μm in diameter in the 180nm technology) so that multiple devices, potentially swarms of them, can be injected into the brain at different locations. These distributed micro-beads can be individually addressed and synchronized to study the interactions between different areas in the nervous system, opening doors for new applications in the neuroscience and neuro-prosthetic field. If our work is successful, the micro-bead will be the smallest wirelessly-powered implant (which allows for neural stimulation and recording) ever fabricated. We expect the micro-bead to usurp the rigid Utah as main electrical neural interface employed in all aspects of neurophysiological studies, but particularly in studies involving many neurons from many areas distrusted around the nervous system.