Fig. 6. (A) An example of a simultaneous extracellular recording from three of the FG efferent nerves, in which an additional early unit participated in the PPN burst (large spikes). The time window shown corresponds to that in Fig. 5B. (B) Here, FC nerve and PPN bursts commence together (compare to Fig. 5Bii). The early PPN activity is dominated by a single unit generating 2-4 high-amplitude spikes. Other PPN units appear to be unaffected by this early unit (see, for instance, the return to low spiking rate between the early PPN activity and the main burst).