Why Weight Loss Surgery Could Affect Memory

A new USC study in Nature Communications gives one possible explanation for food's prominence in our memory. 

Why can we remember specific details that surround foods we eat? NewsMedical.net reports that the body's longest nerve, the vagus nerve, is the autobahn between what scientists have referred to as the "two brains": the one in your head and the other in your gastrointestinal tract. The nerve, they write, is key for telling you the tank is full and to put the fork down because it helps transmit biochemical signals from the stomach to the most primitive part of the brain, the brain stem.

To examine this gut-brain connection, the research team conducted the study on rats. They noticed that the markers in the brain that are key for the growth of new neural connections was affected in rats with a disconnected gut-brain vagus nerve pathway.

The researchers believe that this mind-gut connection is what led cavemen and generations of hunters and gatherers following to remember the locations where they could find foods they enjoyed as well as for supply. 

Scott Kanoski, an assistant professor of biological sciences at USC Dornsife and corresponding author of the paper, says, "When animals find and eat a meal, for instance, the vagus nerve is activated and this global positioning system is engaged," Kanoski said. "It would be advantageous for an animal to remember their external environment so that they could have food again."

The scientists wrote that their findings may raise an important and timely medical question that merits further exploration: Could bariatric surgeries or other therapies that block gut-to-brain signaling affect memory in general? Or at least where we could find our foods?