The stomach's link to the brain

Abstract

Thirty years before Beaumont's publication of his observations of Alexis St. Martin, Pierre Jean Georges Cabanis, a brilliant but now little-known French physiologist, reported clinical data on digestive disturbances that accompany emotional upset. With extraordinary prescience he distinguished emotional states associated with the suppression of digestion from those that were accompanied by accelerated gastric secretory and motor function. However, Beaumont was the first to document the inhibitory effects on digestion by direct observation of the stomach. Later, others documented the excitatory effects, provided further detail concerning emotional states, and began to identify neuronal pathways and humoral mechanisms responsible for the phenomena. The integrative mechanisms in the brain that link life experience to gastric responses have come under study recently; the process has turned out to be immensely complex. Several neurotransmitters have been identified that subserve the facilitatory and inhibitory mechanisms converging on the efferent neurons that ultimately elicit patterns of visceral and general behavior. However, investigations of cognitive and emotional responses to stressful experiences have been largely neglected in humans. Although sophisticated methods and instruments exist that record in a noninvasive fashion a whole spectrum of gastric behavior, such studies are now out of fashion. To fully explore the stomach's link to the brain, research on the entire human organism must be revived.