Sunday 3 November 2002
SFN 2002 - Day 1
Investigator: Herta Flor
by Rabiya Tuma
Researchers in Germany have demonstrated that there is a physiological component to a learned behavior that psychologists have recognized for years: People with chronic back pain whose spouses cater to their needs had more brain activity in response to pain stimulation than those whose spouses try to distract them from the pain.
Herta Flor's team measured brain activity with an array of electroencephalogram (EEG) electrodes placed on the patients' heads. They found that when they gave the patients a small painful stimulus in their backs, all ten of the patients who have solicitous spouses had significantly more activity in the anterior cingulate region of their brains than did the ten patients whose spouses were not so attentive. The brain activity difference between the two groups was about threefold.
Interestingly Flor, a neuropsychologist at the University of Heidelberg, and colleagues detected these large brain wave responses only when the patient's spouse was in the same room and when the pain stimulation was directed to the back. The exaggerated response did not occur either when the spouse was in another room, nor when the stimulation was a painful prick to the finger.
Flor said these data fit right in with a long history of research on learned behavior: "Any kind of behavior that is followed by a positive response is going to be strengthened over time." If every time a patient complains about back pain, the spouse responds with extra attention, by bringing dinner or giving a massage, the patient's brain learns to respond to the pain. But if the spouse offers a distraction such as suggesting a walk, or even if the spouse leaves the room or just doesn't pay attention, the brain has no positive feedback to train a response to the pain or the mere discussion of pain.
This is not a voluntary response, stressed Flor. The excess brain activity occurs on its own and is not under the patient's control - although the researchers are exploring whether they can use biofeedback training to mitigate the brain's response.
Allan Basbaum, a neurophysiologist at the University of California,t San Francisco, told BioMedNet News: "I am not at all surprised by the results." He finds it noteworthy that the patients only had this exaggerated response to back pain and not to a pricked finger, indicating that this really is part of the chronic pain pathway and response - not a response involving the acute pain system.
He also said that he thought the location of the brain response was
intriguing. The anterior cingulate is known to be involved in processing
emotional responses to pain.
© Elsevier Science Limited 2002