Beta bursts mediate amygdala gating of hippocampal emotional encoding

The amygdala and hippocampus are central to emotional processing, yet the transient neural dynamics coordinating these regions remain unclear. We simultaneously recorded single-neuron activity and local field potentials from both regions in epilepsy patients during an emotional image-rating task. Neurons in both regions responded to images with firing rate changes that predicted subjective ratings of extreme pleasantness or unpleasantness. To examine the underlying oscillatory mechanisms, we analyzed beta bursts (13-30 Hz)-transient, high-power events-since conventional spectral analyses revealed no valence-specific patterns. Beta bursts were associated with increased gamma amplitude and enhanced phase coherence in both structures, with beta-gamma phase-amplitude coupling capturing emotion-related dynamics. Critically, amygdala beta bursts strongly suppressed hippocampal firing through interneuron activation during negative valence processing, whereas hippocampal bursts showed no reciprocal influence. These findings suggest that beta bursts provide a temporal code for emotion and represent a candidate mechanism for targeted neuromodulation in mood disorders.