The unique model of this story appeared in Quanta Journal.
It’s late at night time. You’re alone and wandering empty streets in the hunt for your parked automobile once you hear footsteps creeping up from behind. Your coronary heart kilos, your blood stress skyrockets. Goose bumps seem in your arms, sweat in your palms. Your abdomen knots and your muscle groups coil, able to dash or battle.
Now think about the identical scene, however with none of the physique’s innate responses to an exterior menace. Would you continue to really feel afraid?
Experiences like this reveal the tight integration between mind and physique within the creation of thoughts—the collage of ideas, perceptions, emotions, and character distinctive to every of us. The capabilities of the mind alone are astonishing. The supreme organ provides most individuals a vivid sensory notion of the world. It may well protect reminiscences, allow us to study and communicate, generate feelings and consciousness. However those that may try to protect their thoughts by importing its information into a pc miss a important level: The physique is important to the thoughts.
How is this important brain-body connection orchestrated? The reply entails the very uncommon vagus nerve. The longest nerve within the physique, it wends its manner from the mind all through the pinnacle and trunk, issuing instructions to our organs and receiving sensations from them. A lot of the bewildering vary of features it regulates, equivalent to temper, studying, sexual arousal, and concern, are computerized and function with out acutely aware management. These advanced responses have interaction a constellation of cerebral circuits that hyperlink mind and physique. The vagus nerve is, in a single mind-set, the conduit of the thoughts.
Nerves are usually named for the particular features they carry out. Optic nerves carry indicators from the eyes to the mind for imaginative and prescient. Auditory nerves conduct acoustic data for listening to. One of the best that early anatomists may do with this nerve, nevertheless, was to name it the “vagus,” from the Latin for “wandering.” The wandering nerve was obvious to the primary anatomists, notably Galen, the Greek polymath who lived till across the yr 216. However centuries of examine have been required to know its advanced anatomy and performance. This effort is ongoing: Analysis on the vagus nerve is on the forefront of neuroscience at the moment.
Essentially the most vigorous present analysis entails stimulating this nerve with electrical energy to boost cognition and reminiscence, and for a smorgasbord of therapies for neurological and psychological problems, together with migraine, tinnitus, weight problems, ache, drug dependancy, and extra. However how may stimulating a single nerve doubtlessly have such wide-ranging psychological and cognitive advantages? To know this, we should perceive the vagus nerve itself.
The vagus nerve originates from 4 clusters of neurons within the mind’s medulla, the place the brainstem attaches to the spinal twine. Most nerves in our physique department immediately from the spinal twine: They’re threaded between the vertebrae in our spine in a collection of lateral bands to hold data into and out of the mind. However not the vagus. The vagus nerve is one among 13 nerves that depart the mind immediately by way of particular holes within the cranium. From there it sprouts thickets of branches that attain nearly in all places within the head and trunk. The vagus additionally radiates from two main clusters of outpost neurons, known as ganglia, stationed in important spots within the physique. For instance, a big cluster of vagal neurons clings like a vine to the carotid artery in your neck. Its nerve fibers comply with this community of blood vessels all through your physique to succeed in very important organs, from the center and lungs to the intestine.
