PITTSBURGH -- For much of the 20th century, most people thought that stress caused stomach ulcers.
But that belief was largely dismissed 38 years ago when a study, that led to a Nobel Prize in 2016, described the bacterium that generates inflammation in the gastrointestinal tract and causes peptic ulcers and gastritis.
"The history of the idea that stress causes ulcers took a side step with the discovery of helicobacter pylori," said Dr. David Levinthal, director of the University of Pittsburgh Neurogastroenterology & Motility Center. "For the longest time -- most of the 20th century -- the dominant idea was that stress was the cause of ulcers until the early 1980s with discovery of helicobacter pylori that was tightly linked to the risk of ulcers.
"That discovery was critical but maybe over-generalized as the only cause of ulcers," he said.
Now in an important world first, a study co-authored by Levinthal and Peter Strick, both from the Pitt School of Medicine, has explained what parts of the brain's cerebral cortex influence stomach function and how it can impact health.
Published May 18 in the Proceedings of the National Academy of Sciences, the study describes how portions of the brain's cerebral cortex -- including the rostral insula and medial prefrontal cortex -- connect with and can have an impact on the microbiome.
That those areas of the brain also are associated with emotional control helps explain how mental activity -- how you think, feel and prepare to move -- may create an encouraging environment for helicobacter pylori.
"Our study shows that the activity of neurons in the cerebral cortex, the site of conscious mental function, can impact the ability of bacteria to colonize the stomach and make the person more sensitive to it or more likely to harbor the bacteria," Levinthal said.
The study goes far beyond ulcers by also providing evidence against the longstanding belief that the brain's influence on the stomach was more reflexive and with limited, if any, involvement of the thinking brain.
For the first time, the study also provides a general blueprint of neural wiring that controls the gastrointestinal tract.