Functional mapping of the connectivity of the brain is an essential procedure for neurosurgeons aiming for maximal resection of a brain tumor, while minimizing damage to the eloquent cortex. Being able to delineate the location of critical cortical areas in individual patients allows the surgeon to preserve sensorimotor and cognitive functions. Several methods exist for functional mapping, however, none are capable of delivering fast, label free mapping of the cortex with millimeter precision. In this work, we investigate the potential use of infrared neural stimulation (λ=1470nm) as a means of focal stimulation of the mouse cortex in vivo. Here, we show that the application of infrared neural stimulation induces in vivo cortical intracellular calcium signals in Layer II/III mouse neurons, using intravital calcium imaging with the genetically encoded calcium indicator GCaMP6f.