Brain circuit links past experiences to appetite control

Our past experiences shape how much we eat and where and what we choose to eat. Using preclinical models, researchers from Mass General Brigham and the Broad Institute of MIT and Harvard have identified brain cells that translate contextual information into appetite control. The findings suggest that dysfunction in this brain circuit could be a factor in disordered eating and obesity, meaning that these neurons could be a new target for treatment. Results are published in Neuron.

"We identified a neural circuit that is responsible for linking our prior experiences with current aversions and preferences when it comes to dining choices," said senior author Amar Sahay, PhD, of the Department of Psychiatry at Mass General Brigham. Sahay is also a Broad associate member. "These findings may shed light on therapeutics to treat disordered eating in humans such as binge eating that arises in part from loss of contextual control or calibration of eating."

Using mouse models, the researchers showed that Prodynorphin secreting neurons in the dorsolateral septum, DLS(Pdyn), relay information between the hippocampus and hypothalamus, the brain regions that store memories of contexts and control feeding, respectively. Importantly, silencing these cells or deleting the Pdyn gene in these cells prevented mice from associating a prior favorable feeding experience with a location and increased mice's appetite even in a non-familiar location, suggesting that the circuit's activity is shaped by experience, previously learned contexts, and prodynorphin signaling.

The researchers also found that stimulation of DLS(Pdyn) neurons suppressed feeding and promoted avoidance consistent with the role of dynorphin-an endogenous opioid made from prodynorphin that mediates dysphoria or anti-reward signaling-as a chemical signal. Because DLS(Pdyn) neurons also express the receptor for GLP1, this discovery suggests that widely used GLP1 drugs may work in part through this circuit.

"Dysfunction in dynorphin production or in the neural circuits that use it may contribute to disordered eating," said first author Travis Goode, PhD, a Research Fellow in the Sahay lab in the Department of Psychiatry. "Our findings may point toward new brain targets for eating-related issues."