(Royer et al., 2012) showed that phase precession by pyramidal cells is maintained following transient silencing of PV neurons, while the phase can appear to shift. To examine whether our model can account for these observations we simulated transient inhibition of interneurons. (A–B) When interneurons were silenced for 1 s, centered on the place cell’s firing field, phase precession was maintained and on average spike phase appears to advance. (A) Average spike phase (circular standard error) across five bins spanning the length of the place field, for the control simulation and for simulations in which interneurons are silenced (cf. Figure 7c in Royer et al., 2012). (B) The mean shift in spike phase in each bin (cf. Figure 7b in Royer et al., 2012). The relatively minor effects of interneuron silencing in our simulations is a result of the phase locking of cells outside of the place field (before interneuron silencing begins), which ensures that pyramidal cells begin spiking at the correct phase upon place field entry. Despite the lack of any theta coordination via interneuron input inside the place field, their tonic spiking over the place field combined with the correct phase alignment at place field entry is sufficient to generate results similar to those of Royer et al. in the averaged data. (C–D) Simulations as for (A–B), but with silencing of interneurons centered on a random location within 20 cm of the place field center, which may better approximate the conditions in Royer et al. (2012). In these simulations phase precession is again maintained, while the phase change is reduced. Thus, when optogenetic silencing only covers part of the place field, interneuron inputs in the unsilenced portion of the place field further reduce the amount of disruption in the averaged data.