This discovery places the scientific community in an unexplored new continent, said an expert. Since 90 years ago, when Wilder Penfield discovered the inherent relationship between brain signals and the behavior of the immune system, a whole generation of scientists has dedicated themselves to unraveling the way our organs feel, and how they manifest themselves by speaking to the brain, discovering that the nerves that control the basic functioning of the body also influence memory, emotions and the construction of the self.
Nowadays, scientists have contributed new discoveries that, in line with Penfield's premises, expand the understanding of neural and cellular complicity, which experts have called “two-way communication.
This phenomenon is known as interoception. The latest findings, compiled in a "Science" publication, reveal that communication between organs and the brain forms a complex system of nerves and hormones that connect throughout the body.
According to the researchers, the connector par excellence turned out to be the vagus nerve, which, due to its motor and sensory functions, is the network with the largest number of fibers, ranging from more than 100 thousand, and they travel from almost all internal organs to the base of the brain.
Although since the last century, experts knew the transmitting tasks of the vagus nerve, the most recent studies have shown that the signals carried by the vagal fibers, scale beyond those previously known.
Among the findings, the study authors suggest that just as the vagus nerve has the ability to interpret internal changes, it anticipates the body's needs, and sends commands to satisfy them. In addition, its network includes regions of the brain involved in the way we remember, process emotions, and the way we construct the sense of self.
For Catherine Tallon-Baudry, a neuroscientist at the École Normale Supérieure, these discoveries place the scientific community on an unexplored new continent. According to the expert, knowing interoception will broaden the therapeutic objectives that seek the physical and emotional well-being of the patient.
Steve Liberles, a cell biologist at Harvard Medical School, found a type of cells, located in the brainstem, connected to vagal neurons that caused nausea in the rodents studied. The researcher assured that these results could lead to more tolerable chemotherapies, which avoid the side effects of the treatment.
For his part, Scott Kanoski, a neuroscientist at the University of Southern California, was interested in knowing, especially, the relationship of vagal connections with emotions and memories. The expert cut loose cells from a group of rodents that connected the stomach and hippocampus, a brain area associated with memory. As a result, the disruption prevented the animals from remembering new objects and locations, as well as slowed the birth of neurons.
In turn, Diego Bohórquez of Duke University showed that vagal circuits also boost motivation and mood. The neuroscientist came to this conclusion, after discovering the connection of the vagus nerves with neuropod cells, related to nutrition and its impact on the brain.
Accordingly, Ivan de Araujo of the Icahn School of Medicine at Mount Sinai found that stimulating these circuits triggers the release of dopamine in the brain. These studies would explain why we like to eat and how stimulation of the vagus nerve alleviates depression.
To learn more about this phenomenon, researchers have designed a specialized device to stimulate the vagus nerve. However, its methodology is invasive, as it sends pulses of electricity to the bum, through a device implanted below the clavicle.
Despite its technique, the treatment has already been approved in the United States to treat epilepsy and depression. Accordingly, experts are dedicated to designing more careful therapeutic forms, including a transcutaneous atrial.
Penfield was an American neurosurgeon, a pioneer in the study of nervous tissue. The researcher captivated the science of the thirties by his discovery of the relationship between brain signals and the behavior of the immune system, for which he resorted to the use of cartographic and shorthand tools to study brain functions, an unusual practice.
The researcher also estimated the side effects that invasive observation would produce in patients. Among his methods, he stimulated patients with a slight electric shock, which hit different areas of the brain's surface.
From these works, Penfield created the homunculus, a map in which he traced the divisions that are part of the external brain area, which he called the body of the brain. However, his invention lacked precision, as the internal sensory regions were difficult to distinguish. Theoretical gaps, motivated by this lack of clarity, persisted throughout the 20th century.