Project summary
America has an obesity epidemic, which is getting progressively worse and has immense human and
financial costs. While our understanding of homeostatic feeding circuits has advanced steadily over the past
several decades much remains unclear. In addition, much of our food consumption is not due to homeostatic
need, instead, it is often a result of non-homeostatic drivers. Cravings for sugary or fatty foods, even when
sated, drive increased consumption. Stimuli in our environment that signal food availability, including food-
associated visual cues in the form of advertisements, billboards, and candy-bar wrappers, promote these
cravings, and, ultimately, promote consumption. We aim to understand the circuits that drive feeding behavior,
including how food-associated sensory stimuli can hijack normally advantageous neural processes to increase
consumption and contribute to the obesity epidemic.
We propose to determine the role of melanin-concentrating hormone (MCH) neurons in regulating
feeding and responses to food-associated cues. MCH neurons in the lateral hypothalamus and zona incerta
project throughout the brain, including to limbic and higher-order brain regions, and can drive a diverse array of
behaviors, such as feeding, sleep, and learning. Discrete MCH subpopulations likely serve separate functions;
for example, some might promote feeding while others promote sleep or other consummatory behaviors. Our
central hypothesis is that MCH neurons will drive food consumption, increase the rewarding value of
consummatory behavior and enhance responses to food-associated cues through projections to the arcuate
nucleus, nucleus accumbens, and basolateral amygdala.
We will first identify the activity and projection profiles of MCH neuron subpopulations that drive feeding
by mapping specific subpopulations of MCH neurons and recording their activity across a range of feeding
behaviors. We will then activate specific MCH projections to determine if they are capable of driving feeding
behaviors, in addition to other MCH-related behaviors, including sleep. We expect that a specific subpopulation
of MCH neurons projecting to the nucleus accumbens and basolateral amygdala will respond to food rewards
and increase consummatory behaviors. Finally, we will use in vivo two-photon calcium imaging to investigate
the role for MCH activity in forming enhanced behavioral and sensory responses to food-associated cues. By
using cutting-edge tools and approaches to identify the role for the MCH system in feeding behavior and
responses to food cues, we will generate findings that can help to identify cognitive targets and mechanisms
for treating maladaptive feeding behaviors.
