Encoding of environmental cues in central amygdala neurons during foraging

Abstract

In order to successfully forage in an environment filled with rewards and threats, animals need to rely on familiar structures of their environment that signal food availability. The central amygdala (CeA) is known to mediate a panoply of consummatory and defensive behaviors, yet how specific activity patterns within CeA subpopulations guide optimal choices is incompletely understood. In a paradigm of appetitive conditioning in which mice freely forage for food across a continuum of cues, we find that two major subpopulations of CeA neurons, Somatostatin-positive (CeASst) and protein kinase C{delta}-positive (CeAPKC{delta}) neurons can assign motivational properties to environmental cues and encode memory of goal location. While the proportion of food responsive cells was higher within CeASst than CeAPKC{delta} neurons, only the activities of CeAPKC{delta}, but not CeASst, neurons were required for learning of contextual food cues. Since CeAPKC{delta} neurons are known to promote a range of defensive behaviors, our findings point to a model in which CeA circuit components are not organized in specialized functional units but can process both aversive and rewarding information in a context and experience dependent manner. HIGHLIGHTSTwo populations of central amygdala (CeA) neurons, CeAPKC{delta} and CeASst neurons can assign motivational properties to environmental cues and encode memory of goal location. The proportion of food responsive cells was higher among CeASst, than CeAPKC{delta} neurons. The activities of CeAPKC{delta}, but not CeASst, neurons are required for learning of contextual food cues. CeAPKC{delta} neurons represent a "general encoding" population selecting defensive and appetitive responses depending on context.