The subjective experience of pain: Where expectations become reality

Summary & key facts

Researchers showed that what people expect about pain changes both how much pain they say they feel and how their brains respond. They used tests of pain together with brain scans to compare brain activity when people expected different levels of pain and when they actually felt pain. When people were led to expect less pain, they reported less pain and several pain-related brain areas became less active, suggesting expectations can shape real sensory experience.

Key facts:

• The team combined careful pain tests with functional MRI brain scans to study how expectation and actual pain relate in the brain.
• As people expected stronger pain, activity rose in several brain areas, including the thalamus, the insula, the front part of the brain used for thinking, and the anterior cingulate cortex (a brain region involved in emotion and attention).
• Some brain regions responded both to expected pain and to actual pain. In particular, the front part of the insula and the anterior cingulate cortex showed overlapping activity for expectation and experience.
• When the experiment made people expect less pain, they reported feeling less pain and showed reduced activity in pain-related areas such as the primary touch area of the brain, the insula, and the anterior cingulate cortex.
• The results show that a mental image or belief about an upcoming sensation can change the brain processes that build the actual sensory experience.
• The findings help explain why positive expectations sometimes reduce how bad chronic pain or other long-term health problems feel, but they do not prove exactly how this works in all cases.

Abstract

Our subjective sensory experiences are thought to be heavily shaped by interactions between expectations and incoming sensory information. However, the neural mechanisms supporting these interactions remain poorly understood. By using combined psychophysical and functional MRI techniques, brain activation related to the intensity of expected pain and experienced pain was characterized. As the magnitude of expected pain increased, activation increased in the thalamus, insula, prefrontal cortex, anterior cingulate cortex (ACC) and other brain regions. Pain-intensity-related brain activation was identified in a widely distributed set of brain regions but overlapped partially with expectation-related activation in regions, including the anterior insula and ACC. When expected pain was manipulated, expectations of decreased pain powerfully reduced both the subjective experience of pain and activation of pain-related brain regions, such as the primary somatosensory cortex, insular cortex, and ACC. These results confirm that a mental representation of an impending sensory event can significantly shape neural processes that underlie the formulation of the actual sensory experience and provide insight as to how positive expectations diminish the severity of chronic disease states.

Topics

Neural and Behavioral Psychology Studies Pain Management and Placebo Effect Pain Mechanisms and Treatments

Categories

Health Sciences Medicine Physiology

Tags

Anterior cingulate cortex Central nervous system Cingulate cortex Cognition Cortex (anatomy) Insula Insular cortex Medicine Neuroscience Psychology Secondary somatosensory cortex Sensory cortex Sensory system Somatosensory system Thalamus

Conditions & symptoms

Chronic Pain Chronic pain