Interoception: Function, Tasks, Role & Diseases

All perceptions from within one’s own body are summarized as introception. Introception regulates one’s own well-being and encompasses the proprioception of the locomotor and postural apparatus as well as the visceroception of the internal organs. Excessive introception can trigger anxiety disorders.

What is introception?

Interoception works with specialized sensory cells and transmits the information obtained to the central nervous system. Human perceptions have two different sources of stimuli. Exteroception in medicine is the perception of environmental stimuli. The external stimuli are received by stimulus-specialized sensory cells, processed into bioelectric excitation and transported to the central nervous system, where they reach consciousness in processes of interpretation and classification. Through this process, humans form a picture of their surroundings via sounds, smells, tastes, tactile perceptions, and visual stimuli. The opposite of exteroception is interoception. This perceptual structure responds to stimuli from within the individual and is thus an important component of self-perception. Thus, through interoception, a person does not form a picture of the environment, but rather a picture of one’s own bodily processes and thus one’s own organism in space. Interoception also works with specialized sensory cells and transmits the information obtained to the central nervous system. Not all interoceptive stimuli reach consciousness. Thus, interoception is a largely unconscious, albeit permanently occurring, process. Interoception includes proprioception and visceroception. Proprioception includes the senses of movement, force, and position and works with muscle spindles, tendon spindles, bone receptors, and the vestibular organ. Visceral perception is the perception of organ activity. It picks up signals from the internal organs and is also called enteroception.

Function and task

Interoception is the totality of any perception from within the body. This form of perception significantly shapes well-being and determines, for example, whether a person feels healthy or ill. Thus, interoception correlates with subjective well-being and enables the formation of the neurological body schema in the first place. The body schema is understood as the awareness of one’s own body and its limits. The ability of introception is genetically determined, but changes through learning. As a physiological process, interoception consists of several processes. One of them is encoding for stimulus conversion at interoceptors. Stimulus molecules bind to the receptors and convert them into afferent signaling pulse patterns. This is followed by transmission, which corresponds to onward transmission to the central nervous system. For some stimuli, this is followed by the awareness step, which is facilitated by cortical processing. Awareness corresponds to an awareness of interoceptive processes. The totality of the above steps is called the interoceptive system. Interoceptive stimuli can be pain, temperature, itch or touch stimuli. They may be muscular sensations or visceral sensations, information about vasomotor activity, sensations of hunger or thirst. Which stimuli are consciously perceived depends on learning processes and experiences. Various receptors are active as interoceptors. The baroreceptors in the blood vessel walls, for example, permanently measure blood pressure. The brain initiates actions to maintain circulation on the basis of their information. To determine the condition of the blood, ph receptors, carbon dioxide receptors and oxygen receptors sit in the vessel walls to ensure the ideal oxygen supply to the tissues. Osmoreceptors regulate fluid requirements and help the brain signal thirst. Muscle metaboreceptors determine skeletal muscle metabolism, and pancreatic glucose receptors work with the central nervous system to regulate insulin levels. All interoceptors are part of the autonomic nervous system. Mechanoreceptors in the internal organs and tissues are also counted among the interoceptors. They report pressure states and pain. The posture, movement, position and joint receptors are equally introceptive. Thermoreceptors, chemoreceptors and proprioceptors of the position and movement system also belong to the introceptors.A connection to the central nervous system exists via fiber-rich afferents of the motor and vegetative systems. The brain uses the information to regulate homeostasis, posture, movement, and functional adaptation.

Diseases and disorders

Introception plays a role as a component of self-perception in connection with physical changes and thereby with many diseases. What two people consciously perceive from within can vary more or less. Introception is to some extent subjective due to its connections with personal experiences and learning experiences. For example, in some people there is relatively little perception of bodily processes. In others, there is increased interoception. Under certain circumstances, strong interoception can trigger anxiety disorders. In such anxiety disorders, there is an overinterpretation of the smallest changes inside the body, which provoke anxiety reactions and can even trigger physical reactions. This is usually present in people who generally experience anxiety more quickly. Decreased perception of interoceptive stimuli may in turn cause a patient to ignore meaningful alarm signals from his or her own body. Experiential introception disorders can be treated by perceptual enhancement or anxiety disorder treatment. On the other hand, introception may also be physically altered due to neuronal damage or organ damage. Especially in the case of enteroception, this can have life-threatening consequences. If, for example, the baroreceptors in the vessel walls are damaged and do not transmit reliable information, misregulation of the heartbeat and blood pressure occurs. Equally dangerous can be disturbed interoceptors of the gastrointestinal tract, as they upset the regulation of digestion. Such damage can occur, for example, through necrosis of the tissues. However, deep sensitivity in particular can just as easily be disturbed by neurological diseases such as multiple sclerosis (MS). If autoimmunological inflammations of MS, for example, destroy the nerve guidance pathways or regulatory centers of deep sensitivity, severe movement, posture and regulatory disorders occur. In addition, a conceivable cause of physically altered interoception is stroke, which may damage the introceptive brain centers. Such damage can be fatal in severe cases.