Researchers from University College London explored how the hunger signal produced in the gut interacts with the hippocampus, the brain region tied to decision making and behavior. The findings were reported in a neuroscience journal focusing on brain research and neural circuits.
In the study, mice were placed in an environment with limited food availability. The scientists tracked the animals as they experienced hunger or fullness and monitored brain activity in real time to understand how neural signals aligned with their actions. Across the board, all mice showed interest in the food zone, yet only the hungry individuals initiated eating. This suggested a distinct appetitive drive that outweighed curiosity once the animals perceived a lack of energy resources.
As the mice approached the food, activity rose in a specific set of neurons located in the ventral portion of the hippocampus. This neural boost appeared to play a role in inhibiting the act of eating in certain contexts, indicating that the hippocampus could exert a restraining influence on feeding behavior when energy balance was not severely compromised.
When hunger intensified, the pattern shifted. The same hippocampal region showed reduced activity, and the brain network no longer suppressed the appetite-driven action of eating. This change correlated with higher circulating levels of ghrelin, a hormone released by the gut that signals hunger to the brain.
To test causality, scientists stimulated ventral hippocampal neurons in hungry animals, successfully prompting them to refrain from consuming the available food. An alternative approach yielded a similar outcome by removing receptors that respond to ghrelin from these neurons, thereby diminishing the gut-to-brain hunger signal through this pathway.
The researchers envision that these results offer new avenues for understanding how eating behaviors are regulated and how disruptions in ghrelin signaling within the hippocampus could contribute to eating disorders. By mapping the precise brain circuits that link gut signals to decision making about food, they aim to illuminate potential targets for therapeutic strategies in the future.
Earlier work touched on approaches to weight management that involved altering the function of certain genes, highlighting the broader interest in how genetic and hormonal factors shape appetite and energy balance. This study adds to that conversation by detailing a clear gut-to-brain mechanism that modulates the urge to eat through hippocampal activity.