New research suggests the digestive system may play a role in which food-related experiences the brain turns into memories, according to ScienceDaily. The study, led by USC Dornsife professor Scott Kanoski, focused on how signals from the gut may help shape memory formation when food is involved.
Published in Nature Communications, the work examined the vagus nerve, a major communication pathway between the digestive system and the brain. Researchers found that when rats ate nutrient-rich foods, acetylcholine increased in neurons linked to the hippocampus, a brain region important for learning and memory.
When the scientists disrupted vagus nerve communication, acetylcholine no longer rose after eating, and the rats had more trouble remembering where they had recently found food. The team also found that the brain responded to the nutritional value of food rather than just how sweet it tasted.
According to the study, rats that consumed sugar or fat showed strong activity in memory-related pathways, while animals given low-calorie or noncaloric sweet liquids did not show the same response. That suggests a sweet taste alone was not enough to trigger the same memory system.
The researchers also reported that rats fed high-fat and high-sugar diets early in life later showed weaker gut-to-hippocampus communication, even after switching back to a healthier diet. Kanoski said the findings may help explain links between poor nutrition, obesity and cognitive decline, and could point to future vagus nerve-based approaches for supporting memory.
