Scientists launch $14.2 million project to map the body’s “hidden sixth sense”

Now, a collaborative team from Scripps Research and the Allen Institute has received the National Institutes of Health (NIH) Director's Transformative Research Award to develop the first comprehensive atlas of this internal sensory system.

A Major Investment in Brain-Body Research

Leading the project is Nobel Prize-winning neuroscientist Ardem Patapoutian, joined by Li Ye, the N. Paul Whittier Chair in Chemistry and Chemical Biology at Scripps Research, and Bosiljka Tasic, Director of Molecular Genetics at the Allen Institute. Xin Jin, Associate Professor at Scripps Research, will serve as co-investigator, directing the genomic and cell-type identification work.

The NIH has awarded the team $14.2 million over five years to carry out this ambitious project.

"My team is honored that the NIH is supporting the kind of collaborative science needed to study such a complex system," says Patapoutian, the Presidential Endowed Chair in Neurobiology at Scripps Research.

Patapoutian, who shared the 2021 Nobel Prize in Physiology or Medicine for his discovery of cellular sensors that detect touch, will now apply his expertise to understanding interoception.

"We hope our results will help other scientists ask new questions about how internal organs and the nervous system stay in sync," adds Ye. Like Patapoutian, he's also a Howard Hughes Medical Institute Investigator.

Established in 2009, the Transformative Research Award funds groundbreaking interdisciplinary projects that push beyond traditional scientific boundaries. It is part of the NIH Common Fund's High-Risk, High-Reward Research Program, designed to support innovative ideas that could reshape our understanding of human health but might otherwise struggle to receive funding through conventional mechanisms.

What Makes Interoception Unique

Unlike the classic senses -- such as smell, sight, and hearing -- which rely on specialized sensory organs that detect stimuli from the outside world, interoception involves a vast network of neurons that sense what's happening inside the body. These neural circuits track critical processes including circulation, digestion, and immune activity.

Because interoceptive signals originate deep within the body and are often processed unconsciously, scientists often describe this system as our "hidden sixth sense."

Despite its fundamental role, interoception has received little scientific attention. The signals it produces are complex, overlapping, and difficult to measure. The sensory neurons that carry them are distributed throughout organs such as the heart, lungs, stomach, and kidneys, making them hard to isolate and map precisely.

Mapping the Brain-Body Connection

With the NIH's support, the Scripps and Allen Institute researchers plan to map how sensory neurons connect with a wide variety of internal organs, including the heart and gastrointestinal tract. Their goal is to create a detailed anatomical and molecular atlas that reveals how these neural pathways are organized.

To achieve this, one part of the project will label sensory neurons and use whole-body imaging to trace their routes from the spinal cord to different organs, producing a high-resolution 3D map. The second part will use genetic profiling to distinguish between different cell types, such as neurons that send signals from the gut, bladder, or fat tissue.

Together, these datasets will form the first standardized reference for understanding the body's internal sensory wiring.

Why Interoception Matters for Health

By decoding how interoception works, scientists hope to uncover key principles of brain-body communication that could lead to new treatments for disease. Disruptions in these internal sensory pathways have been linked to a range of conditions, including autoimmune disorders, chronic pain, neurodegenerative diseases, and high blood pressure.

"Interoception is fundamental to nearly every aspect of health, but it remains a largely unexplored frontier of neuroscience," says Jin, who's a Howard Hughes Medical Institute Freeman Hrabowski Scholar. "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."