But for approximately 50 million people in the United States, that alarm system gets stuck 'ON'. This is the reality of chronic pain, where the signal persists for months or years, long after any physical injury has healed. As neuroscientist J. Nicholas Betley of the University of Pennsylvania explains, chronic pain isn't just an injury that won't heal; "it's a brain input that's become sensitized and hyperactive."
Now, groundbreaking research is shedding light on how to quiet this constant noise, pinpointing a specific group of brain cells that act like a neural override switch for long-term pain.
Survival Over Suffering: The Discovery of Y1 Receptor Neurons
Betley and collaborators from the University of Pittsburgh and Scripps Research Institute have focused their attention on a group of brainstem cells known as Y1 receptor (Y1R)-expressing neurons. These cells are located in the lateral parabrachial nucleus (lPBN) and play a critical role in how the brain prioritizes survival.
The key insight came from an unexpected observation: states of urgent need, such as intense hunger, thirst, or fear, seemed to have the power to lessen chronic pain. Betley noted, "When it came to chronic, lingering pain, hunger seemed to be more powerful than Advil at reducing pain."
This inspired the team to investigate the brain's "built-in way of prioritizing urgent survival needs over pain."
The Neural Switchboard
The research, published in Nature, confirms that the brain does, in fact, have circuits that can reduce the activity of neurons transmitting pain signals.
The scientists observed that Y1R neurons showed "tonic activity"—they kept steadily firing during prolonged pain, like an engine left running even after the car is parked. This ongoing neural hum may be the source of chronic pain.
They then identified the signaling molecule responsible for the pain-quieting effect: neuropeptide Y (NPY).
When a survival instinct—like escaping a threat or finding food—takes priority, neurons activated by these threats release NPY.
NPY then acts on the Y1 receptors in the lPBN to actively dampen the ongoing pain signal.
Former graduate student Nitsan Goldstein perfectly describes the mechanism: "It's like the brain has this built-in override switch... NPY quiets the pain signal so that other survival needs take precedence."
Paving the Way for New Treatments
This discovery is much more than just a fascinating piece of neuroscience; it offers concrete hope for millions.
A New Biomarker and Target
For years, clinicians have struggled because there's no clear biological marker for chronic pain when a physical injury isn't present. Patients are in pain, but the source seems invisible.
Betley is excited about the potential to "use Y1 neural activity as a biomarker for chronic pain." The research suggests that the problem often lies not at the site of an old injury, but "in the brain circuit itself." Targeting these specific Y1R neurons opens up an entirely new path for drug developers and clinicians.
Behavior as a Treatment
The finding that this pain-regulating circuit is flexible—that it can be "dialed up or down" by things like hunger or fear—also has major implications for non-pharmacological treatments.
This suggests that behavioral interventions such as:
Exercise
Meditation
Cognitive Behavioral Therapy (CBT)
may be effective because they influence how these very brain circuits fire. According to Betley, "The future isn't just about designing a pill. It's also about asking how behavior, training, and lifestyle can change the way these neurons encode pain."
WNCTimes
Image: WNCTimes
By pinpointing the Y1R neurons in the lPBN, scientists have discovered a master switch, offering a powerful new framework for developing personalized treatments that finally get to the brain source of chronic pain.
Source: University of Pennsylvania. "Scientists discover brain circuit that can switch off chronic pain." ScienceDaily. ScienceDaily, 10 October 2025. 251009033126.htm>.