The brain and stomach communicate through the nervous vago. It is one of the nerves that protrudes from the spinal bulb and reaches the stomach through the other organs that are on the way. The signals go in both directions, from the brain to the stomach, and from the stomach to the brain, and other experiments have shown that the signals that go from the stomach to the brain are related to modulation of mood, anxiety, and fear.
Researchers at the ETH University have cut the way from the stomach to the brain to some laboratory rats and have studied their influence on the intrinsic anxiety of the rats and on the fear conditioned or learned, compared to the rats of the control team that have complete communication pathways. Standard experiments have shown that rats that have suspended stomach and brain communication feel less anxiety than those of the control group, less fear of open areas and strong bright.
The results of experiments to measure conditioned fear have been different. In these experiments, rats have learned to associate a sound to an unpleasant experience, and the learning process has been similar to the interruption or integrity of nerve links. On the contrary, in the process of relearning to associate this same sound to a neutral experience and stop associating it to a bad experience, rats with suspended nerve links have been much slower. That is, the conditioned fear has been maintained for longer than healthy rats.
Researchers have considered this latest discovery interesting to treat people with posttraumatic stress disorder. These people are afraid of a certain stimulus because they associate it with a very bad experience. Researchers believe that with the excitation of the venous nerve a treatment pathway can be opened to learn to relate these stimuli to situations that will not make them feel afraid. Vagal nerve stimulation is currently used to treat epilepsy and certain depressions.
In addition to analyzing the behavior of rats, researchers have analyzed their brains and have found that the production of noradrenaline and neurotransmitters GABA in rats with suspended nerve ties is different in certain zones of the limbic system.
According to the researchers, research shows that the stomach has a direct role in fear, and that the interruption of the signaling path that goes from the stomach to the brain modifies the patterns of behavior complexes. The results have been published in the journal The Journal of Neuroscience.