An example of the firing pattern-mimicking behavior of hippocampal interneurons is the theta phase precession of their spikes. In contrast to pyramidal cells, the spikes of hippocampal interneurons are either locked to a narrow phase of the theta cycle or show broad phase distribution with dominant locking to the trough. However, whenever an interneuron spikes display a transient phase shift, its phase precession slope is similar to that of the pyramidal cell(s) to which the interneuron is monosynaptically connected (Maurer et al., 2006b). Because multiple interleaving place cell assemblies are present in a given theta cycle (Figure 6), it is expected that the active assemblies induce selective firing in their own interneuron targets at discrete theta phases. This is indeed the case (Figure 9C, D). While the firing rate of the example interneuron in Figure 9C gives little indication that it is driven by neurons taking part in two assemblies, two separate phase precession cycles are clearly revealed in ‘phase-space’ (arrows in Figure 9C). Using the spike phase information, two distinct place-related firing patterns of the same interneuron can be
