a, A novel integrated fluidic-tetrode probe (fprobe) allows for simultaneous LFP recording and delivery.Front view and back view of the fprobe. The fluidic channel of 50x20 µm dimensions is visible in the back view. A picture from the scanning electron microscope (SEM) is shown at the top-right to highlight outlet ports in the surface of the fprobe. b, Ripples and other LFP signatures can used to precisely target the hippocampal cell layers. SP, stratum pyramidale. c, Precise delivery of 50 nL of Texas red to mark the CA1 pyramidal layer (blue, bisbenzimide staining) in electrohysiological experiments aimed to modify ripple dynamics.