This Journal of Neuroscience paper by Song and Xu et al. from Dr. Ileana Hanganu-Opatz’s lab presents electrophysiology and optogenetics results using NeuroNexus multi-shank, multi-fiber optoelectrodes (A4x4-5mm-100-125-703-OA16LP). The lateral coverage from multiple shanks positioned recording sites in both layers 2/3 and 5/6 of developing mouse (ages P8-10 and P20-24) prefrontal cortex (PFC). They tested excitation and connectivity between PFC and hippocampus (CA1) in a model of mental disorder.