Project Summary: The Neuroimaging and Electrophysiology Facility (NIEF) was established to increase the competitiveness of scientists in Puerto Rico via the incorporation of microscopy and electrophysiology techniques in their research projects. This aim was achieved by the establishment of two research cores, one at the Molecular Science Research Center (MSRC) and another at the Institute of Neurobiology (INB), from the University of Puerto Rico. Both facilities support a diversified group of investigators on the island. During phases 1 and 2 of COBRE, the NIEF acquired state-of-the-art instruments that are expensive and not accessible in most laboratories, departments and/or institutions. Among the equipment obtained or supervised by the NIEF are confocal, two-photon, and super resolution microscopes. Also available are electrophysiology rigs for oocytes, cultured cells, brain slice, and anesthetized animals to monitor cell electrical activity. As a result of the NIEF research infrastructure and expert technical personnel, 113 peer reviewed manuscripts have been published, leading to 1,816 citations. Moreover, data obtained from the NIEF cores were included in 84 grant proposals that were submitted to federal, state, and private agencies, and from those submitted, 48 were funded. Furthermore, research performed in the NIEF permitted the innovation of new technology by supporting investigators with the development of 7 patents. Finally, over 50 graduate students from eight different departments and three main research institutions have benefitted from the NIEF cores by being able to complete at least one of their theses aims and attain their academic degrees, thus demonstrating the impact of the NIEF in the scientific community of Puerto Rico. These results confirm the beneficial impact of the NIEF cores on the investigators in the island. Therefore, in this COBRE phase 3 proposal, the goal is to maintain, strengthen, and support the NIEF cores by implementing three aims: 1) to provide scientists in Puerto Rico with state-of-the-art instrumentation in microscopy and electrophysiology, 2) to support the investigators in the island with expert staff that will help them with the acquisition and analysis of the data from microscopy and electrophysiology techniques, and 3) to train researchers in several technologies associated with these two approaches (microscopy and electrophysiology) via seminars, workshop, and hands-on training. Thus, the facilities and services will continue to help investigators use the most innovative electrophysiological and microscopy technology to generate interdisciplinary projects to study biological and biophysical phenomena under the guidance of experienced and excellent staff. Fulfillment of these aims will enable a transition of the NIEF to a completely self-sustained facility beyond COBRE phase 3 and a role model for Puerto Rico and the Caribbean.