To further test this hypothesis, we evaluated correlations between fast gamma power and defensive behavior within animals on a trial-by-trial basis. Consistent with fast gamma being a safety-signal, freezing rates on individual trials were inversely correlated with fast gamma power, while simultaneously being positively correlated with theta-gamma coupling strength (Figure 3D). Both of these effects were significant across the population (Figure 3E; p<.001 and p<.05, respectively; multiple linear regression, MLR). There was no significant correlation between slow gamma power and trial-by-trial freezing rates, although there was trend towards a positive relationship (Figure S5E; r=.354; p=0.11, MLR). Overall, these data suggest that in the BLA, fear-associated theta simultaneously organizes fast gamma oscillations and decreases their power. This is reversed during safety, when local theta less effectively organizes fast gamma oscillations and fast gamma power is elevated.
