A new study published in the journal Nature Metabolism identified specific neurons in the hippocampus that store food-related memories, directly influencing overeating and body weight, according to Science Daily. These neurons play a role in excessive food intake and diet-induced obesity.
The research team identified a food-specific memory system in the brain, including two previously uncharacterized populations of neurons in the dorsal hippocampus that are differentially responsive to post-ingestive fats and sugars. These neurons are critical in forming memories related to food and driving eating behaviors.
Dr. Guillaume de Lartigue from the Monell Chemical Senses Center led the study that found memory influences what and how much we eat, providing direct evidence for a causal relationship between memory and sucrose intake. "These neurons are critical for linking sensory cues to food intake. Their ability to influence both memory and metabolism makes them promising targets for treating obesity in today's food-rich world," said de Lartigue, according to Science Daily.
The researchers found that silencing these neurons disrupts the animal's ability to recall memories related to sugars, thereby reducing its sugar consumption and preventing weight gain, even when exposing the test mice to diets that contribute to weight gain. Conversely, reactivating these neurons enhances food-related memories and increases food consumption, as noted by Science Daily.
Sugar-responsive neurons encode and influence only sugar-related memories and intake, indicating their specific role in the memory system. Similarly, fat-responsive neurons impact only fat intake, reported Science Daily. These neurons do not affect other types of memory, such as spatial memory for non-food-related tasks, as stated by MedicalXpress.
By targeting hippocampal memory circuits, it may be possible to disrupt memories that stimulate the consumption of calorie-rich foods, offering a method to combat overeating and obesity.
"Although it is not surprising that we remember experiences of eating delicious foods, it was long assumed that these memories had little to no impact on eating behavior," said de Lartigue, according to Vice News. "The surprising thing is that inhibiting these neurons can prevent weight gain and affect the response to meals rich in fats and sugars," he continued, as reported by NeuroTech.
The researchers confirmed that eliminating the neurons that respond to sugars in the hippocampus of mice not only disrupts food memories but also reduces the amount of sugar the animal consumes and protects against weight gain.
These findings reveal that the dorsal hippocampus contains glutamatergic neuronal populations that selectively encode post-ingestive fat and sugar signals, suggesting a potential neural basis for macronutrient-specific choice, reported Nature. The researchers observed that mice with ablated sugar-responsive dorsal hippocampus neurons exhibited a 50% decrease in sucrose consumption compared with controls, with no effect on fat intake, as noted by Science Daily.
The motivational effects of dorsal hippocampus neurons appear to be specifically tied to food-related contexts, rather than representing a general reward system, suggesting that these memory circuits may drive overeating in modern environments.
This article was written in collaboration with generative AI company Alchemiq