Your body is constantly communicating with your brain, sending silent signals about everything from your heartbeat to your blood pressure. It’s an ongoing internal conversation that keeps you alive. However, it is also a system that science still barely understands.
Now, a new $14.2 million research effort led by Scripps Research Institute, a non-profit medical research center based in San Diego, California, aims to change that by mapping the body’s mysterious “hidden sixth sense.”
The five-year project, funded through the National Institutes of Health (NIH) Director’s Transformative Research Award, will attempt to decode interoception—the process by which the nervous system monitors and interprets internal physiological signals.
Researchers hope their work will produce the first-ever atlas of this inner sensory system, revealing how the brain keeps tabs on vital functions such as breathing, digestion, and immune responses.
“My team is honored that the NIH is supporting the kind of collaborative science needed to study such a complex system,” Scripps project lead, Dr. Ardem Patapoutian, said in a statement.
Dr. Patapoutian is no stranger to decoding the body’s hidden senses. In 2021, he was awarded the Nobel Prize in Physiology or Medicine for discovering how cells sense touch and pressure, a finding that fundamentally reshaped our understanding of sensation. Now, he and colleagues at Scripps believe that interoception could hold the key to the next great understanding of how the brain maintains internal balance.
Interoception isn’t like the classic five senses. You can’t see or hear your blood pressure or digestion. Instead, this “sixth sense” operates through a network of sensory neurons that relay information from deep inside the body to the brain, often without conscious awareness.
These neurons weave through organs and tissues—heart, lungs, stomach, kidneys—forming a hidden communication network that ensures your body’s systems stay in sync.
The project represents a partnership between Scripps Research and the Allen Institute, combining expertise in molecular genetics, whole-body imaging, and neuroscience. Dr. Patapoutian will be joined by Dr. Li Ye, the N. Paul Whittier Chair in Chemistry and Chemical Biology at Scripps Research, and Dr. Bosiljka Tasic, Director of Molecular Genetics at the Allen Institute.
The NIH Director’s Transformative Research Award is part of the agency’s High-Risk, High-Reward Research Program, designed to fund bold ideas that push scientific boundaries. Established in 2009, the NIH describes the award as “supporting exceptionally innovative and/or unconventional research projects with the potential to create or overturn fundamental paradigms.”
Interoception remains one of biology’s least understood systems, partly because it’s so difficult to study. Unlike external senses that rely on clearly defined organs—eyes, ears, nose—interoceptive pathways are diffuse and overlapping. Signals from the heart, gut, or lungs intermingle as they travel to the brain, blurring the boundaries between systems.
Since the sensations monitored by interoception originate deep within the body and are interpreted largely without our conscious awareness, researchers often liken it to a kind of “hidden sixth sense.” Understanding how this internal sensory network functions could profoundly reshape how medicine approaches everything from stress regulation to chronic disease.
With NIH backing, the researchers plan to systematically map how sensory neurons connect to internal organs, including the heart and gastrointestinal tract.
The anatomical phase of the project will involve labeling these neurons and tracing their paths from the spinal cord into specific organs using high-resolution, whole-body imaging. This process will generate a three-dimensional map of the routes and branching patterns that make up the body’s internal communication system.
At the same time, the molecular arm of the project will use genomic profiling to classify different neuron types—identifying, for instance, how cells that transmit signals from the gut differ from those that transmit signals to the bladder, lungs, or fat tissue.
“We hope our results will help other scientists ask new questions about how internal organs and the nervous system stay in sync,” project participant and Howard Hughes Medical Institute Investigator, Dr. Li Ye, explained.
Together, these complementary datasets will form the first comprehensive atlas of the interoceptive system—a foundational reference that could help explain how body and brain coordinate to maintain internal stability, or homeostasis.
Though the hidden “six sense” label might give off parapsychology vibes, interoception has very tangible links to health and disease. Dysregulation of interoceptive signaling has been tied to a broad spectrum of conditions, including chronic pain, anxiety, hypertension, autoimmune disease, and even neurodegenerative disorders like Parkinson’s. Understanding how these signals are wired and how they malfunction could open the door to new diagnostic tools and therapies.
Put simply, interoception connects virtually every organ system. If researchers can accurately map how that communication works, science might begin to understand why it breaks down and how to fix it.
The new NIH-backed effort also reflects a broader shift in modern science to recognize that the human sensory experience extends far beyond the traditional five senses.
Researchers are increasingly exploring how the body detects and interprets a far wider range of internal and external cues, from subtle electromagnetic changes to microbial signals within our own gut.
Just recently, The Debrief reported that scientists have proposed models of seven or more human senses based on new evidence of specialized brain wiring. Other recent research has uncovered “neurobiotic” pathways, suggesting that microscopic organisms in our bodies can communicate directly with the nervous system.
Even in the animal world, discoveries of hidden sensory systems, like the “sixth sense” in geckos and desert ants, have raised new questions about whether humans may possess similar, still-untapped perceptual abilities.
Together, these findings point to an emerging frontier in biology, where understanding how we sense ourselves may be just as revolutionary as how we sense the world around us.
For Dr. Patapoutian, this work continues his decades-long pursuit of uncovering the body’s sensory secrets. Just as his earlier discoveries revealed how cells translate physical forces into biological signals, this project could uncover how the brain interprets the body’s invisible rhythms.
Ultimately, decoding interoception could reshape everything from medicine to mental health, shedding light on how our physical and emotional states are intertwined. From stress responses to immune regulation, this internal dialogue between organs and the nervous system forms the foundation of what it means to feel alive.
“Interoception is fundamental to nearly every aspect of health, but it remains a largely unexplored frontier of neuroscience,” Scripps Research Associate Professor, who will lead the genomic and cell-type identification portion of the project, Dr. Xin Jin, explained.
“By creating the first atlas of this system, we aim to lay the foundation for better understanding how the brain keeps the body in balance, how that balance can be disrupted in disease, and how we might restore it,” Jin said.
Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan. Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com