Meal Memory Neurons that Influence Eating Behavior Identified

University of Southern California researchers have identified a distinct group of neurons in the ventral hippocampus of laboratory rats that form “meal engrams”—memory traces that store details about what and when food is consumed. Published in Nature Communications, the study suggests that these specialized brain cells could explain why people with memory issues, such as dementia or brain injuries, may overeat due to forgetting recent meals.

Meal engrams are activated during eating, particularly in brief pauses between bites when the brain surveys the environment. These moments allow the hippocampal neurons to integrate information about the meal, including the setting and timing. According to Scott Kanoski, corresponding author, “Meal engrams function like sophisticated biological databases that store multiple types of information such as where you were eating, as well as the time that you ate.”

The research highlights the potential impact of distracted eating. Activities like watching television or using a phone during meals may prevent the brain from properly forming meal memories, leading to weak or incomplete engrams. First author Lea Decarie-Spain explained, “The brain fails to properly catalog the meal experience, leading to weak or incomplete meal engrams.”

Using advanced neuroscience tools, the team observed real-time brain activity in rats as meal memories formed. When these meal memory neurons were destroyed, rats forgot food locations but retained other spatial memories, indicating a specialized system for meal-related information. These neurons also communicate with the lateral hypothalamus, a region involved in hunger. Blocking this connection caused rats to overeat and forget meal locations.

Kanoski noted that these findings may inform future treatments for obesity and weight management, emphasizing that remembering what and when you eat could be as important as food choices themselves.