Amygdala beta bursts modulate hippocampal neuronal dynamics during human emotional processing

The amygdala and hippocampus are key structures in emotional processing, yet the transient neural dynamics coordinating their interaction remain poorly understood. We simultaneously recorded single-neuron activity and local field potentials from these regions in epilepsy patients performing an emotional image-rating task. Neurons in both regions exhibited firing rate changes predictive of subjective emotional valence. While conventional spectral analysis revealed no valence-specific patterns, beta bursts (13-30 Hz)-transient, high-power events-were selectively modified by task features. In both regions, beta bursts were associated with increased gamma amplitude and enhanced phase coherence, with beta-gamma phase-amplitude coupling capturing emotion-related dynamics. Critically, amygdala beta bursts were associated with valence-dependent, bidirectional modulation of hippocampal interneuron firing - decreased during very unpleasant/highest arousal processing and increased during high-arousal very pleasant processing - while putative pyramidal-cell firing did not change significantly. Hippocampal bursts showed no reciprocal influence. These findings suggest that beta bursts may represent a temporally precise neural correlate of emotional appraisal and a potential target for neuromodulation in mood disorders.