Graphical Abstract and Summary
The basolateral amygdala (BLA) plays a vital role in associating sensory stimuli with salient valence information. Excitatory principal neurons (PNs) undergo plastic changes to encode this association; however, local BLA inhibitory interneurons (INs) gate PN plasticity via feedforward inhibition (FFI). Despite literature implicating parvalbumin expressing (PV+) INs in FFI in cortex and hippocampus, prior anatomical experiments in BLA implicate somatostatin expressing (Sst+) INs. The lateral entorhinal cortex (LEC), a brain region carrying olfactory information, projects to BLA where it drives FFI. In the present study, we asked whether LEC input mediates plasticity in BLA and explored the role of interneurons in this circuit. We combined patch clamp electrophysiology, chemogenetics, unsupervised cluster analysis, and predictive modeling and found that a previously unreported subpopulation of fast-spiking Sst+ INs mediate LEC→BLA FFI and gate plasticity. Our study raises the question whether this circuit is involved in plasticity in olfactory learning.
Footnotes
New physiology, morphology, and control data added. Figures updated for better data display. Additional discussion added.
