Indeed, we observed highly synchronous slow and fast gamma oscillations in all three brain regions (Figure 6). During epochs of strong BLA gamma oscillations (>1.5 SD above mean power), we found that fast gamma oscillations were phase-synchronized across structures, as shown in gamma-triggered traces and coherograms (Figure 6A). Both BLA-mPFC (n=22) and BLA-vHPC (n=11) fast gamma phase-phase differences had a strong peak near 0, which was not found for a shift-predictor (Figure S7A). Similar results were obtained when the BLA was referenced to a cerebellar screw and other brain regions were referenced to a frontal screw, demonstrating that observed gamma dynamics reflect synchronous oscillations rather than high frequency activity in the reference (Figure S7B). These changes were specific to the BLA-mPFC-vHPC circuit, as the dHPC (n=9) was not strongly engaged in gamma-gamma coupling with the BLA (figure 6A).
