I-Corps: Implantable Brain-Computer Interface with Integrated Optics and Electrodes

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

The lack of a systematic theory of neural activity is complicated by the scale of the human brain, with an estimated 85 billion neurons, 100 trillion synapses, and 100 chemical neurotransmitters. Understanding what makes any one neuron fire or not is a central question in neuroscience and so the ideal sensing tool must span from the single neuron to its network of connections if we are to understand how that particular "cell type" assimilates information. Through recent advance in optogenetics, specific cell types can be activated and/or silenced by optical control using specific wavelengths to achieve high precision manipulation of cellular activity. Combined with an electrical recording system, an optogenetic probe can simultaneously stimulate and record from targeted neural population with high spatiotemporal resolution. In spite of recent rapid advances in optogenetics, supporting technologies to reliably deliver light to and record electrical signals from deep brain structures are not readily available. Early work involving in vivo optogenetics relied on the manual assembly of commercially available components such as microwires and optical fibers, which are not only bulky but can also experience large misalignments due to human error. This I-Corps team has developed the technical solutions to support optogenetic applications using advanced micro-fabrication techniques to monolithically integrate optical and electrical components into a compact MEMS probe. The technology allows for multiple micro-LEDs or waveguides to be precisely aligned on the same probe shank with the recording electrodes, obviating the need for hybrid processes to assemble components onto the probe shank. This, in turn, leads to increased scalability of the number of light sources per probe shank, minimized shank dimensions, and provides individual control of light sources for confined emission at cellular resolution and multiple locations. The probes the team has designed are practical to fabricate in bulk wafer processes with high yield and require minimal assembly effort. Excellent performance has been demonstrated in acute and chronic, behaving animal models through collaborations with several world-class neuroscience labs. The impact of this technology can be categorized by its utility in either research or clinical applications: to support optogenetic research where neuroscientists control cells through light to study brain functions; to better understand and to treat neurological diseases (Parkinson's, epilepsy, etc.), and to restore lost body functions (deafness, blindness, artificial limbs, etc.).