Inhibitory Circuits in the Basolateral Amygdala in Aversive Learning and Memory

Abstract

Neural circuits in the basolateral amygdala (BLA) play a pivotal role in the learning and memory formation, and processing of emotionally salient experiences, particularly aversive ones. A diverse population of GABAergic neurons present in the BLA orchestrate local circuits to mediate emotional memory functions. Targeted manipulation of GABAergic neuronal subtypes has shed light on cell-type specific functional roles in the fear learning and memory, revealing organizing principles for the operation of inhibitory circuit motifs in the BLA.

Keywords: GABAergic; anxiety; axo-axonic; chandelier; fear; parvalbumin; somatostatin; stress.

Figure 1

GABAergic neuronal diversity and circuit organization in the basolateral amygdala. (A) Types of GABAergic neurons color coded based on cytosolic protein expression: Somatostatin (SST), Neurokinin 1 (NK), Vaso intestinal peptide (VIP), cholecystokinin (CCK), Parvalbumin basket cell (PV-BC) and Parvalbumin chandelier cell (PV-CC) and Neurogliaform (NGFC). Dotted box indicates classification of groups based on synaptic target on principal neurons. Neurons with distinct cytosolic proteins tend to make distinct synaptic connections. (B) Schematic showing organization of circuit 'motif's formed on principal neurons and interneurons in the BLA. Bottom filled cell indicate excitatory axo-axonic chandelier interneuron; “+” excitatory connection, “–” inhibitory connection. (C) Schematic of a simplified BLA circuit model shows arrangement of different interneuron subtypes and putative circuit motifs shown in (B).