John Campbell, Ph.D.
Organisms must eat to survive, but energy consumption, storage, and use, collectively known as energy balance, is a complex process. The brain plays a central role in this process by monitoring the organism’s energy needs and storage and adjusting its energy intake accordingly. However, the relevant neuron populations, and the circuits they form, are largely unknown. Our lab is therefore working to identify these neuron populations, their circuits and specific roles in energy balance.
First, we identify the neuron populations using high-throughput single-cell transcriptomics and unsupervised clustering analysis. This analysis reveals genetic markers that we then use to gain genetic access to specific neuron populations, map their synaptic circuitry, and monitor and manipulate the activity of specific circuits in vivo. Such functional studies can link genetically-defined neuron populations with specific behaviors and physiologic processes, ultimately leading to a mechanistic understanding of how the brain controls energy balance. Our previous work generated a comprehensive “census” of cell types in the arcuate hypothalamus and median eminence and uncovered several novel types of neurons that potently control feeding behavior (Nature Neurosci, 2017a,b; Nature Neurosci, 2016). We are also examining distinct neural circuits that control different functions of the digestive system, including gastric motility and insulin secretion. Together these studies will advance our understanding of how brain controls energy balance by revealing the cell types, signals, and circuits that make it possible.