Pain is not only a physical sensation—it carries an emotional burden that can turn short-term discomfort into chronic suffering. Now, new research from the Salk Institute reveals a brain circuit that may explain why some people experience prolonged emotional distress from conditions like fibromyalgia, migraines, and PTSD.

A New Pathway in Pain Processing

Traditionally, scientists believed that the brain handled the sensory and emotional aspects of pain through separate neural systems. However, a recent study published in Proceedings of the National Academy of Sciences (July 9, 2025) has challenged this model. The Salk research team identified a specific group of neurons in the thalamus—a central hub in the brain—that appears to link sensory pain signals directly to emotional processing areas, including the amygdala.

“These findings suggest that a branch of the sensory pain pathway also plays a central role in shaping the emotional experience of pain,” says Dr. Sung Han, senior author and associate professor at Salk.

Why Pain Feels Worse for Some

The thalamus receives input from the spinal cord via the spinothalamic tract, long known as the sensory pain highway. But Han’s team discovered that a particular set of thalamic neurons—marked by the presence of CGRP (calcitonin gene-related peptide)—connect to the brain’s emotional centers and may be responsible for amplifying the emotional dimension of pain.

In experiments with mice, when these CGRP neurons were turned off, the animals still sensed pain (such as heat or pressure), but they no longer showed fear or avoidance behaviors. Conversely, when the neurons were activated without any actual painful stimulus, the mice showed strong emotional reactions and avoided the area altogether.

“This tells us that suffering isn’t just about detecting pain—it’s about how the brain interprets that pain emotionally,” explains Dr. Sukjae Kang, first author of the study.

Implications for Chronic Conditions

This research helps explain why people with fibromyalgia, migraine, or PTSD often feel intense, lingering pain without a clear injury. It may be due to overactivation of this CGRP-related brain circuit, causing the brain to misinterpret normal sensory input as threatening or painful.

Interestingly, several migraine medications that block CGRP activity are already in clinical use. These findings may now clarify why they are effective and could lead to new, non-addictive treatments for emotional and chronic pain.

The study also hints at a broader role for this brain circuit in conditions involving heightened sensitivity or hypervigilance, such as PTSD. By quieting this neural pathway, future therapies could help reduce emotional overreactions, fear, and avoidance behaviors in trauma-affected individuals.

However, more research is needed to determine how this circuit might relate to emotional pain from social experiences like grief or heartbreak.

“This discovery gives us a clearer understanding of the neural bridge between pain and suffering,” says Han. “It opens the door to therapies that could truly ease both the physical and emotional burdens of chronic pain”.