Integrated photonics chip for neural activity investigation

Understanding the central nervous system and the human brain in particular represents one of the most challenging endeavors in current science. This interest is not only driven by the need to find new methods for curing neural disorders. Increasing efforts are dedicated to the development of hardware mimics of the nervous system in the form of artificial neural networks for computational purposes, which also reflects substantial interest in a deeper understanding of the brain's functionality. Here, we present a nanophotonic approach to enable a precise investigation of neural activity at the level of a single synapse. Key component is an integrated photonic chip, which serves as a platform for neural growth. Our simulations show, that an optogenetically modified nerve cell in close vicinity to a photonic waveguide can be efficiently stimulated by the waveguide's evanescent field, even with a low optical input power in the order of microwatts. These results pave the way for designing a versatile analysis tool to investigate both the behavior of individual neurons and their synergistic function in a neural network at the same time.