25/08/2024
Making Sense of Interoception by Molly McDonough for Harvard Medical School -- How we perceive what’s happening inside our bodies and what that means for our health.
Even when the world around us seems quiet, our insides are bustling. Much of the time we’re unaware of the tumult within — of cells shifting shapes, organs releasing chemicals, or blood vessels dilating. But sometimes a signal breaks through, and we feel a pang of hunger, a fullness of the bladder, or a racing heartbeat. It’s a call from the body to the mind that something’s off, a plea for a return to balance.
This type of sensation has a name: interoception, which is loosely defined as the perception of internal signals from the body. While the five commonly recognized senses — sight, hearing, touch, taste, and smell — help us understand the world around us, interoception processes information from the heart, gut, lungs, and more as our internal organs interact with the brain.
Evidence is mounting that these internal senses are integral to keeping the body in balance and could be implicated in a number of medical conditions, such as anxiety, addiction, eating disorders, and chronic pain. Yet compared with our knowledge of the external senses, “for a long time we knew almost nothing at a molecular and cellular level about interoception,” says Stephen Liberles, a professor of cell biology in the Blavatnik Institute at HMS. That’s why Liberles and other researchers are exploring the molecular underpinnings of mind-body links, reshaping our understanding of how we sense what’s happening inside us and why it matters that we do.
MIXED SIGNALS
Take a pause, but don’t take your pulse: can you feel your heartbeat? In the early 1980s, German psychologist Rainer Schandry wondered whether some people might be better at perceiving their bodily processes than others. So, he asked a group of study participants to count their heartbeats simply by sensing them, without using their fingers to check their pulse. Schandry found that although participants’ heart rates didn’t vary much, some participants counted the number of beats far more accurately than others. Curiously, those who were better at sensing their heartbeats were more likely to report having anxiety.
The heartbeat-counting task became a go-to measure of the ability, known as interoceptive attention or interoceptive accuracy, to sense what’s happening inside one’s own body, and the task was applied in the ensuing decades to the study of many other psychiatric and neurological conditions. But whereas Schandry linked anxiety to increased interoceptive accuracy, later studies often found that individuals with autism, eating disorders, or depression were worse at perceiving their heartbeats or other sensations.
Perhaps, researchers posited, there’s a happy medium when it comes to interoception: You want to be aware of the messages your body is sending, but not too aware. A number of interventions have been introduced to find that balance. Most are used in the context of mindfulness-based practices, such as cognitive behavioral therapy. Some focus on helping patients reconnect with their bodily sensations, using mindful breathing or movement to treat anorexia or pain. Others, such as those used to treat anxiety, involve conditioned exposure to the sensations that trigger stress.
Wen Chen stands outside in a red dress with her arms crossed, looking to the left of the camera with a slight smile.
Wen Chen
Wen Chen, MMSc ’98, PhD ’03, a branch chief at the National Center for Complementary and Integrative Health (NCCIH), part of the National Institutes of Health, was first exposed to the idea of interoception through these types of interventions. Given her interest in integrative health, she found the concept compelling, but as a neurobiologist, she noticed the researchers in her orbit were mostly focusing on the philosophical, clinical, and psychological dimensions of interoception. Nobody seemed to be diving into the fundamental science behind it. “I had this moment where I thought, what actually is interoception,” she says.
https://magazine.hms.harvard.edu/articles/making-sense-interoception?fbclid=IwY2xjawE4BpFleHRuA2FlbQIxMAABHdxoGOC-LHKJX0V57lDFnIwLMuqW-5ySSrWIjShEzd_jJmb6UJgIsYOQPQ_aem_REnqLOcKSBiE7LIMPafdPw
How we perceive what’s happening inside our bodies and what that means for our health
