A new University College London study reveals that a newborn’s response to pain is more complex and less conscious than previously thought.
Researchers have discovered that while premature babies can physically feel pain, they lack the emotional and cognitive capacity to fully interpret or understand it—an insight that could reshape how neonatal care is approached in hospitals around the world.
“Pain is a complex experience with physical, emotional and cognitive elements,” said lead author and neuroscientist professor Lorenzo Fabrizi in a statement.
In adults, pain processing involves a network of brain regions known as the ‘pain connectome’, where each part contributes to different aspects of the pain experience.
“In newborn babies, this network is underdeveloped, which could mean that pain experience in newborns is totally different from the way we, as adults, understand it,” Fabrizi explained.
In their study, the researchers used advanced MRI data from more than 370 preterm and full-term infants—some as early as 32 weeks gestation—to analyze how the brain’s pain connectome forms over time.
This network of brain regions, responsible for sensing, reacting to and cognitively evaluating pain, matures in stages with different components developing at different points before and after birth.
Fabrizi and his colleagues focused on three major components of pain processing: Sensory-discriminative (identifying where and how intense the pain is), affective-motivational (the emotional response to pain) and cognitive-evaluative (interpreting and understanding the meaning of pain).
Their findings suggest that the ability to simply feel pain—the sensory-discriminative network—begins to resemble adult levels of connectivity between 34 and 36 weeks after conception, but the emotional and interpretive responses lag behind.
At around 36 to 38 weeks, the affective-motivational network matures, allowing infants to recognize pain as unpleasant or threatening.
However, the cognitive-evaluative network—responsible for contextualizing or “understanding” pain—doesn’t reach adult-like maturity until well beyond 42 weeks, meaning even full-term newborns aren’t fully capable of interpreting pain experiences.
“These results challenge assumptions about the completeness of infant pain perception and raise new concerns about how pain is managed in neonatal care,” Fabrizi said.
The study builds on earlier findings by the same research team who reported in 2023 that premature babies don’t habituate to repeated pain, such as from medical procedures. In essence, their brain does not “adjust” or reduce its response to ongoing painful stimuli.
The new research helps explain why. Without mature cognitive or emotional pain-processing systems, premature infants may feel the same pain repeatedly without developing coping mechanisms or psychological resilience.
“Our results suggest that preterm babies may be particularly vulnerable to painful medical procedures during critical stages of brain development,” Fabrizi said.
This emphasizes the importance of informed pediatric care, including tailored pain management and carefully timed medical interventions, he concluded.
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Reference
Jones, L., Batalle, D., Meek, J., Edwards, A. D., Fitzgerald, M., Arichi, T., & Fabrizi, L. (2022). Differential maturation of the brain networks required for the sensory, emotional, and cognitive aspects of pain in human newborns. PAIN. https://doi.org/10.1097/j.pain.0000000000003619
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