the same time, considering that theta is phase-synchronized across the regions [38] (Figure 1). Maximal firing probability of cells in the superficial layers of entorhinal cortex occurs immediately after the theta phase associated with maximal gamma power [39]. CA1 place cells have also been reported to exhibit maximal firing immediately after the theta phase associated with maximal fast gamma power [14]. Thus, theta-fast gamma coupling in MEC and CA1 may allow entorhinal spikes to arrive when hippocampal cells are likely to respond. Also, fast gamma synchronization of MEC spikes may produce a more powerful output from MEC and thereby increase spiking in CA1, as has been shown to occur during gamma coordination of V1 inputs to V2 [40].
