Distinct roles of beta and gamma bursts in the mouse basolateral amygdala-medial prefrontal cortex circuitry in the presence of a predatory robot

Abstract

Oscillatory activities in the basolateral amygdala (BLA) are known to regulate emotion-related behaviors with the medial prefrontal cortex (mPFC). Several studies on the rodent BLA have reported that transient oscillations at the high beta (~25 Hz, beta bursts) and low gamma (~40 Hz, gamma bursts) frequency range emerge during the emotion- or reward-related situations. However, whether the beta and gamma bursts have similar or different neuronal contexts is unclear. To characterize the functional roles of the beta and gamma bursts in the BLA-mPFC circuit, we examined their relevance to mouse behaviors by introducing a predatory robot in the open field arena. To classify the behavioral states, we used the dynamic parameters of the position data to classify the response of the mice towards or their interactions with the robot (e.g., attack, escape, freeze, avoid, etc.). We observed that the BLA-mPFC circuit predominantly displays both beta and gamma bursts in a significant level compared to the baseline. However, the moments during which these bursts occurred showed discrepancy: while most of the beta bursts were associated with the executive behaviors, the gamma bursts didn’t show such behavior-specificity. Rather, the gamma bursts occurred in an elevated manner during the situations of enhanced threat. Our observations so far concede with the recent findings and suggest the updated view of high beta and low gamma oscillations. Even the resonance frequencies are at proximate, the generative mechanisms of beta and gamma oscillations are different. The beta and gamma bursts in the mPFC and BLA may reflect distinct functional role in emotional and non-emotional cognitive processes.