Neural Mechanisms of Ingestive Behavior

Interoception includes processes by which an organism senses, integrates, interprets, and regulates internal signals that contribute to physiological processes such as eating. In this context, more is known about ascending brain pathways for postoral signals than about descending pathways (e.g. central regulators) that alter processing of this sensory information. In fact, NIH has identified our limited understanding of how forebrain central regulators modulate ascending interoceptive signals and its impact on behavior as critical knowledge gaps. Importantly, eating is not only regulated by postoral sensory signals but also by oral sensory signals (e.g. taste). Despite its public health importance, major gaps exist in our understanding of how central regulator nuclei influence neural coding of ascending sensory information and its impact on ingestive behavior. This proposal seeks to broaden our knowledge of how an anatomically/molecularly defined central regulator pathway contributes to taste coding and ingestive behavior. We have identified amygdala (CeA) cells that express GABA and somatostatin (Sst) as a source of several distinct central regulator pathways. One such pathway provides input to a region of the pons called the parabrachial nucleus (PBN - CeA/Sst-to-PBN pathway). The PBN is critical to processing oral and postoral signals that strongly influence the foodstuff an animal chooses to ingest. Our central premise is that this central regulator pathway mediates, in part, the neural processing of interoceptive information and, consequently, influences ingestive behavior. We will use Sst-cre mice in conjunction with cre-dependent retrograde viruses to specifically label and optogenetically manipulate CeA/Sst neurons. Our complimentary aims will expand knowledge of how CeA/Sst-to-PBN neurons influence ingestive behavior driven by oral and postoral signals, neural processing of taste information in the PBN, and neural activity of other CeA/Sst regulator neurons that differ in terms of where they project in the brainstem (i.e. NST vs. PBN).