Schematic representation of basic connectivity patterns between IO axon, PC, and CN neuron. A–C, The three possible ways to connect an IO axon, a recorded PC, and a recorded CN neuron are shown along with schematic CS–CN correlograms that each would be expected to produce. D, An alternative connection pattern caused by the branching of IO axons to multiple PCs that would produce a similar CS–CN histogram as that shown in A. Yellow electrodes indicate which cells are being recorded.