Pain-related cerebral activation is altered by a distracting cognitive task

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Pain Research

Background:

• Attentional mechanisms are known to modulate sensory brain region activity during parallel cognitive processing.
• The role of attention in pain processing, particularly during concurrent cognitive tasks, requires further investigation.

Purpose of the Study:

• To investigate attention-related modulations in brain activity during pain processing.
• To determine if cognitive demands alter the brain's response to painful stimuli.

Main Methods:

• Regional cerebral blood flow was measured using [(15)O]butanol and positron emission tomography (PET).
• Participants underwent a cold pressor test for pain and a computerised perceptual maze test for cognitive demand.
• Brain activity was compared between conditions of pain alone, cognitive task alone, and combined pain and cognitive task.

Main Results:

• The cognitive task alone activated brain regions consistent with previous studies.
• Pain processing activated the primary somatosensory cortex (S1), somatosensory association areas (S2), anterior cingulate cortex (ACC), and mid-insula.
• Activity in somatosensory association areas and the periaqueductal gray/midbrain decreased during the combined task, correlating with reduced pain ratings.
• Lateral orbitofrontal regions showed increased activity during combined pain and cognitive tasks, suggesting frontal cortex involvement in pain modulation.

Conclusions:

• Attentional mechanisms, engaged through a cognitive task, can significantly modulate pain processing in the brain.
• Reduced activity in specific pain-processing areas and lower subjective pain ratings indicate that cognitive demands can dampen pain perception.
• The increased activity in lateral orbitofrontal regions suggests a top-down regulatory role of the frontal cortex in pain modulation during divided attention.