Along with shifts in theta frequency lead, theta-gamma coupling changed dynamically as well, such that BLA fast gamma was strongly coupled to local BLA theta in some epochs, and to mPFC theta in others. On trials when coupling to mPFC theta predominated, gamma power was higher; when coupling to BLA theta predominated, gamma power was lower (Figure 7F). These findings suggest a competitive mechanism between BLA and mPFC theta-frequency inputs for control of the fast gamma circuit within the BLA, and provide evidence for a relationship between mPFC control over BLA gamma and safety signals.
