The term visceroception includes all sensory body systems that perceive the state and activity of internal organs, such as the digestive system and cardiopulmonary circulation. The various sensors report their perceptions mostly through afferent pathways of the autonomic nervous system to the brain, which processes the messages further. Most messages proceed unconsciously, so that after processing, the brain independently initiates further control of the internal organs.
What is visceroception?
The term visceroception includes all sensory body systems that perceive the state and activity of internal organs, such as the digestive system and cardiopulmonary circulation. Visceral perception, also called enteroception, under which the multiple sensory observations and messages of the state and activity of the internal organs to the brain are subsumed, is part of interoception. Interoception includes all messages from the body about internal states, thus also messages from proprioception and the sense of balance about radial and linear accelerations. There are a wide variety of sensors, each specialized for a task, that register certain pressure conditions, oxygen saturation, degree of hydration, degree of gastric filling, and much more, and report them to specific ganglia or brain centers via afferent pathways of the autonomic nervous system. The use of the autonomic nervous system indicates that most of the messages are unconscious, that is, unnoticed by us. The control of the internal organs based on the visceroceptive messages is also largely unconscious, but is also subject to a more or less strong influence by the sympathetic and parasympathetic systems, which have a very strong influence on metabolism and thus on the behavior of the internal organs toward tension and peak physical performance (sympathetic) or toward relaxation and growth (parasympathetic). The processing of visceroceptive messages in the central nervous system (CNS) corresponds in large part to the genetically predetermined circuitry in the brain, but in part also to experiences acquired during life, to which the body’s metabolism can adjust.
Function and task
As already explained above, visceroception runs largely autonomously, i.e. unconsciously. This relieves the human being enormously, since he does not have to consciously deal with how strong and fast the heart should beat, how high the blood pressure should be, how much digestive enzymes should be produced in the stomach and pancreas, how each of the dewy muscles should move and how many other things should be controlled. It can be seen that visceroception not only relieves, but enables coordinated bodily functions in the first place, since humans would be completely overwhelmed if the multitude of processes had to be consciously controlled. However, there are also situations with which the autonomic nervous system is overtaxed. These are, for example, immediate dangers that require conscious decisions about whether we avoid an imminent danger by fleeing or whether we try to eliminate the cause of the danger, e.g. by attacking. Injuries also require individual decisions about further behavior. In these cases, nociceptors (pain sensors) ensure that pain also reaches the level of consciousness. In many other cases, too, visceroceptive sensors or the autonomic nervous system have the ability to place certain states on the level of consciousness. This is not just a matter of producing feelings of anxiety or discomfort, but can extend to fainting. Fainting serves the immediate protection of the body in the case of injuries that have already occurred or in the case of imminent severe injuries. Peripheral blood vessels constrict and circulation is reduced to an absolute minimum, so that as little blood loss as possible occurs in the event of injury and consciousness is spared any traumatic experiences to the greatest extent possible.
Diseases and ailments
Given the multitude of mechano-, chemo-, baro-, thermo-, and osmoceptors, as well as many more different sensors that relay their “measurements” to the CNS, there may be disturbances in the sensing, transmission, or procession of signals. Conceivable are disturbances or failures of individual sensors due to injuries or due to local exposure to chemical substances.Failures or erroneous messages of individual sensors usually have no effect, since with the large number of sensors involved, the message of a single receptor hardly plays a role in the procession of the total messages. In cases where a whole group of sensors is impaired by a disease of the corresponding organ, serious misinterpretations of the situation by the CNS may well occur, which can trigger corresponding malfunctions of the affected organ. For example, if visceroceptors of the digestive tract are impaired in their function by a disease of the stomach or intestine, significant digestive problems may result due to organ dysfunction. Similar problems and discomfort can occur when transmission is impaired. Various neurological diseases such as multiple sclerosis (MS), autoimmune diseases, strokes, or neuritis that result in impaired conduction of action potentials trigger similar symptoms, even life-threatening conditions. The CNS cannot control the organs according to reality without correct messages from visceroception, so serious health problems may result due to the malfunctions. Another problem may arise at the interface of unconscious or conscious perception. As stated above, most sensory messages are not perceived consciously, but only in specific situations that require conscious individual intervention. The decision whether a particular state is raised to consciousness varies greatly from individual to individual and is controlled both by genetically determined neural connections and by experience. If the threshold that triggers awareness of states is too low, this can trigger anxiety and further neuroses that are detrimental to health. But the opposite, too low awareness of organ states, can also be detrimental to health because early warning signs of impending illness, such as heart attacks and the like, are not perceived.
