We were all taught about the five senses in school: sight, hearing, smell, taste, and touch. However, we also know that there are things our body senses, such as a gut feeling, and we don’t really know how to explain it. Yes, we have a sixth sense, and—although we’ll spare you the references to the famous movie starring Bruce Willis and Haley Joel Osment—there are scientists who have become obsessed with unraveling how our bodies are able to sense certain things without using the first five basic senses.
What many of us call intuition or a gut feeling, experts have given a more scientific term: interception.
Thanks to an initiative supported by the leading biomedical research agency in the United States, a group of scientists has been able to prove that we do indeed possess this sixth sense that has been historically ignored. They have been able to create the first three-dimensional map of this vital network, thanks to an investment of no less than US$14.2 million.
The mysterious human sixth sense
Interoception is a system of continuous monitoring of the body, a kind of constant conversation that takes place below our mental consciousness. Interception is our body’s ability to sense, interpret, integrate, and regulate signals that come exclusively from within the body. Unlike the other five traditional senses, interoception focuses on critical internal variables rather than stimuli from the external world.
Interception is what monitors our heart rate, the need to breathe, blood pressure, blood sugar levels, thirst, hunger, and immune activity (in short, almost everything that happens inside us).
This ability is essential for allostasis, the sophisticated process by which the body maintains physiological balance by anticipating internal needs before they become critical. It is the sense to which we owe our physical survival; thanks to it, you realize that someone is following you down the street, even if you haven’t seen them, or that someone is picking your pocket or backpack. It is a kind of superpower that allows you to be in tune with your surroundings and detect possible sources of danger.
The NIH’s million-dollar investment
The largest sponsor of this study has been the National Institutes of Health (NIH). This is the US federal government agency dedicated to biomedical research and public health. This money is channeled through the Transformative Research Award (TRA), part of the High Risk, High Reward Program.
Interoceptive Dysfunction
Prior to this large-scale neural project, previous research had already established interoception as a critical factor in multiple medical conditions. One of the findings is that interoceptive dysfunction is a transdiagnostic risk factor. Patients with anxiety have been shown to experience hyperactive interoception, which interprets benign bodily signals—such as a slightly accelerated heartbeat—as imminent threats that amplify stress and lead to possible panic attacks.
In other mental illnesses such as depression, interoception may be dampened or “turned off,” making it difficult to identify emotions or even physical pain. This core deficiency is linked to a lack of interoceptive awareness is known as alexithymia, the ability to recognize and describe one’s own emotions based on bodily sensations.
Interception is also key in eating disorders. Difficulty perceiving hunger signals can facilitate dietary restriction, while lack of awareness of satiety can contribute to excessive food intake. One of the greatest successes attributed to drugs such as GLP is their ability to reset hunger signals. For a person who constantly thinks about food, using this medication has allowed their brain to, in their words, “turn off a white noise radio that was playing all day.”
In the treatment of chronic conditions, complex disorders such as fibromyalgia and chronic fatigue syndrome have also been found to involve dysregulated interoceptive processes. In fact, some theories suggest that chronic psychosomatic pain could be due to a residual interoceptive image, in which the brain continues to have a defective body representation, even when the tissue damage has been completely healed and repaired.