PROJECT SUMMARY The proposed study combines novel electronics and microfabrication techniques to create a non-invasive, research platform for targeted stimulation and characterization of human peripheral nerves. This Phase II proposal involves two significant developments for high-resolution peripheral nerve interfacing. Aim 1 will develop high-resolution and low-noise skin surface electrode arrays. Each electrode within the array will consist of cost-effective micropatterned needles, which significantly decrease electrode impedance by pain- lessly piercing the topmost layer of skin, thereby providing high spatial resolution without sacrificing signal- to-noise ratio. Aim 2 will develop miniaturized stimulation and recording electronics to recover signals tra- ditionally obscured by stimulation artifacts. The recovered data, combined with the ability to simultaneously interact with dozens of skin-surface electrodes, will allow non-invasive mapping, characterization, and con- trol of peripheral nerves. In addition to reducing the complexity, pain, and training required to monitor and manipulate peripheral nerves, this platform will allow for continued innovation in disease diagnostics, sur- face electromyography, neural prosthetics, intraoperative monitoring, and therapeutic stimulation.