COLUMN

Interoception and Psychosomatic Medicine

  • “Feeling well” “not feeling well”
  • “Physically tense/ relaxed”
  • “Hungry/ full”

The sensory system that detects these physiological states inside the body is called “interoception”.

It is the body’s internal sensor, so to speak. You may think, “I know what is going on in my body. However, there are many things you may not be aware of, such as not noticing when you are tired. If you are not feeling well but work too hard without realizing it, you will eventually collapse. This internal sensor is very important for maintaining good health.

Two levels of Interoception

There are two main levels of interoception: unconscious and conscious level of interoception.

The internal state of the body is perceived and adjusted unconsciously, even if we are not consciously aware of it. This is the function of the sense of internal receptivity at the unconscious level. For example, when food enters the stomach and digestion is required, the vagus nerve activates peristalsis and digestive activity in the gastrointestinal tract. The sensing of such a state is not often brought to the conscious mind. This is due to the first, unconscious (subconscious) level of internal receptive sensation.

However, when too much food enters the stomach and the stomach becomes full to bursting, the feeling of stomach fullness becomes conscious, and the (conscious) realization that “I can’t eat any more” leads to the action of “stop eating”. This is the second, conscious level of interoception. This is sometimes referred to as “interoceptive awareness.”

Mechanism of Interoceptive Awareness

So, how does the body capture internal states? With the recent development of neuroscience, the mechanism of interoception has gradually been elucidated.

The center of interoception is in areas responsible for physiological regulation functions such as the insular cortex and the limbic system in the brain. At the functional level of the brain, the level of the central limbic system plays an important role.

This is a level slightly deeper than areas involved in higher mental functions or cognitive functions that are normally consciously aware. However, we maintain our physical and mental health every day thanks to this sensor.

Awareness of Mind and Body

The sensory perception of mind-body sensations that lead to conscious awareness and action is called “awareness.”
It relates to the second level of “conscious level of interoception” mentioned earlier.

Being aware of one’s own emotions and body is important for the treatment of physical and mental health conditions, including stress-related disorders. If this is not appropriate, negative emotions may not be noticed and may lead to physical discomfort. Also, even if you are full, overeating can lead to a breakdown in physical and mental health and is related to dieting.

〇 State of decreased “awareness of emotions”: Not aware of what emotions you are feeling = Alexithymia
〇 State of decreased “awareness of body”: Not aware of changes in one’s physical condition = Alexisomia

These are called and are one of the characteristic features closely related to psychosomatic disorders. Please refer to the links for each item for more information on these. Interoception is important as the physiological basis of these conditions.

Interoception as the Basis of Emotions

Thus, interoception serves as the basis for awareness of both mind and body. Not only that, but it is deeply involved in the formation of emotions such as joy, anger, sadness, and happiness, and research is also progressing in psychology. Needless to say, emotions are very important in our lives. Through these emotions, we can lead a richer and more human life.

It is also said that “emotions are rooted in the body.” When the body is in good condition, positive emotions such as joy and happiness are more likely to occur, and when the body is in poor condition, negative emotions such as sadness and anger are more likely to occur, as everyone has experienced.

With good interoception, awareness of both mind and body improves, the functioning of the body’s functions such as the autonomic nervous system improves, and judgment becomes more appropriate. Furthermore, a richer life is possible through rich emotions.

As this mechanism becomes clearer, there is the potential to enhance health by dealing effectively with one’s own mind and body, and in medical care, there is hope for better approaches to stress-related disorders.

(Kanbara K, LABs Psychosomatic Medicine, https://psychosom.net/en/column/interoception, Jan 2022)

Related Columns, Articles, and Research
Related Projects

Alexisomia Research Association
 http://body-thinking.com/alexisomia/

References

Kanbara, K., Fukunaga, M. Links among emotional awareness, somatic awareness and autonomic homeostatic processing. BioPsychoSocial Med 10, 16 (2016). https://doi.org/10.1186/s13030-016-0059-3