A recent study has provided new understanding of how the brain interprets and combines pain signals. The research not only identifies areas in the brain that react to pain but also explains the processes that aid in the integration of pain information. Utilizing functional magnetic resonance imaging (fMRI), the researchers demonstrated how the brain merges anticipated pain with the actual intensity of painful experiences.
A study led by Associate Director WOO Choong-Wan from the Center for Neuroscience Imaging Research (CNIR) at the Institute for Basic Science (IBS), along with Michael YOO Seng Bum, Assistant Professor of Biomedical Engineering at Sungkyunkwan University, has brought to light new insights into how the brain interprets and assimilates pain signals. Their work goes further than pinpointing brain regions involved in pain, as it uncovers the mechanisms that enable the brain to integrate this pain-related information. The team employed fMRI to explain how the brain aligns its expectations of pain with the actual severity of painful stimuli.
Pain is a multifaceted experience that is shaped not only by the severity of the painful stimulus but also by personal expectations. For example, one’s anticipated pain can influence how the actual pain is perceived. Earlier studies have identified brain regions responsible for these individual factors affecting pain perception, but this new research investigates how these different aspects merge to create a unified pain experience.
KIM Jungwoo, the lead author of the study, remarked, “It’s not only important to identify which brain regions matter; understanding the origin of pain is crucial for identifying ways to alleviate unnecessary pain.”
The researchers performed fMRI scans on participants subjected to varying pain levels, while also adjusting their expectations regarding the intensity of pain they might feel. To gain a complete understanding of how the brain processes pain, they broke down the process into two stages: preservation (how the brain retains information about pain expectations and the intensity of stimuli) and integration (how these factors fuse together to create a unified pain perception). They assessed these stages across different levels of the brain’s cortical hierarchy*, anticipating that lower-level networks would preserve information without synthesizing it, while higher-level networks would both preserve and integrate the information.
Unexpectedly, results revealed that all neural networks, irrespective of their level, preserved both pain expectation and stimulus intensity information. However, integration of this information occurred only in higher-level networks, which simply combined the preserved expectation with stimulus data. This indicates that while the entire brain retains pain-related information, only specific regions are tasked with merging diverse pain signals into the subjective experience of pain.
This study marks a significant collaborative effort spanning two domains of neuroscience. Dr. Yoo, who specializes in decision-making and electrophysiology, partnered with Dr. Woo, an expert in fMRI and pain research, to examine how the brain processes pain information holistically. Their pioneering approach illuminates the mechanisms through which the brain handles pain, presenting insights that could inspire new strategies for managing chronic pain.
Co-lead author Michael YOO Seng Bum commented, “This was a valuable collaborative study that synergized the strengths of each lead investigator, allowing us to move beyond merely reporting activation of certain regions and enabling us to explore how information is integrated throughout the brain.”
Co-lead author WOO Choong-Wan characterized the research as “an innovative investigation utilizing geometric information captured in brain activation patterns to unveil the integration mechanisms of various types of pain information,” emphasizing that “this breakthrough would not have been viable without collaboration.”
* Cortical Hierarchy: The brain processes information in a tiered fashion, with lower-level networks (such as sensory and motor networks) managing fundamental sensory input, while higher-level networks (like the limbic system and default mode network) are responsible for integrating more complex information. This study leveraged this framework to comprehend how the brain processes and integrates pain signals at various levels.
