Pain, a universal human experience, serves as a distress signal from the body, alerting us to potential injury or harm. While the perception of pain originates in our sensory nerves, it is the remarkable complexity of the brain that allows us to interpret and modulate this sensory input. The brain wields incredible power in shaping our experience of pain.
In this fourth article in a series of posts focusing on communicating complexity with clarity, Associate Medical Writer Vincent Huynh outlines his research into how brain structure and function could be related to a healthy individual’s ability to control pain.
Understanding the brain in pain modulation
Chronic pain is experienced in over 30% of people worldwide and exerts an enormous personal and economic burden, with therapies demonstrating variability in effectiveness. This variability could be related to how individuals naturally regulate or modify their experience of pain, which is still poorly understood.
This study examined how brain structure and function could be related to pain modulation. The authors investigated pain control in a group of 42 healthy individuals, using a research framework called conditioned pain modulation (CPM), which aims to understand how the physical properties of stimuli, such as their intensity or duration, influence our psychological experiences, such as our perceptions, judgments, and decision-making processes. They also studied the size of different brain areas and how they communicate with each other in relation to how individuals regulate or modify their experience of pain.
The findings showed that better pain control (i.e., stronger inhibition) was related to larger frontal brain areas on the left side and stronger synchronicity between the motor cortex and a region called the periaqueductal grey – a key region involved with descending pain modulation. On the other hand, a weaker ability to control pain was related to larger frontal brain areas on the right side and stronger synchronicity between the right frontal cortex and the primary somatosensory cortex, and connections between the amygdala and posterior insula. All these regions are involved with sensory and emotional-affective dimensions of pain processing.
Overall, the study found a relationship between interindividual pain modulatory function and the structure and function of brain regions involved in pain control in healthy individuals. Ultimately, understanding the variability between individuals in pain processing could help optimise therapeutic strategies in those who do develop chronic pain.