扁桃体 Axo-axonic 細胞は恐怖連合学習を制御する

抄録

Activity and plasticity of excitatory neurons are tightly regulated by local inhibitory neurons in a spatiotemporal specific manner. Axo-axonic cells (AACs) are a unique type of inhibitory neurons that express parvalbumin and innervate the axon initial segment (AIS) of excitatory neurons. While their anatomical features have been identified, the genetical marker and functional role remain unclear. Here, we show that vasoactive intestinal peptide receptor 2 (Vipr2)-expressing inhibitory neurons in the basolateral amygdala (BLA) exhibit the anatomical and electrophysiological properties typical of AACs. Furthermore, using an AACs-specific labeling approach, we conducted in vivo fiber photometry recording and functional inhibition experiments in a cued fear conditioning test. The activity of AACs was increased for both conditioned stimulus (CS: tone) and unconditioned stimulus (US: foot-shock), and inhibition of GABA transmission of AACs impaired cued fear conditioning. These results suggest that AACs are important for memory acquisition. Finally, we employed projection-specific monosynaptic rabies virus tracing to identify the direct monosynaptic inputs cells to AACs in the BLA. This study provides new insights into the detailed functional roles of AACs in the BLA.