Encoding of Environmental Cues in Central Amygdala Neurons during Foraging

Abstract

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 not completely understood. In a paradigm of appetitive conditioning in which mice freely forage for food across a continuum of cues, we found that two major subpopulations of CeA neurons, Somatostatin-positive (CeA^Sst) and protein kinase Cδ-positive (CeA^PKCδ) neurons, can assign motivational properties to environmental cues. Although the proportion of food responsive cells was higher within CeA^Sst than CeA^PKCδ neurons, only the activities of CeA^PKCδ, but not CeA^Sst, neurons were required for learning of contextual food cues. Our findings point to a model in which CeA^PKCδ neurons may incorporate stimulus salience together with sensory features of the environment to encode memory of the goal location.

SIGNIFICANCE STATEMENT The CeA has a very important role in the formation of memories that associate sensory information with aversive or rewarding representation. Here, we used a conditioned place preference paradigm, where freely moving mice learn to associate external cues with food availability, to investigate the roles of CeA neuron subpopulations. We found that CeA^Sst and CeA^PKCδ neurons encoded environmental cues during foraging but only the activities of CeA^PKCδ neurons were required for learning of contextual food cues.