Brain processes ongoing pain more emotionally

March 11, 2015
The picture shows the EEG results during a short (left) and a long-lasting pain stimulus (right). The brain areas with the strongest activity are depicted in red. Short pain stimuli are processed in sensory brain areas, whereas ongoing pain is processed in frontal brain areas which are related to emotional processes. Credit: E. Schulz et al., 2015, Prefrontal gamma oscillations encode tonic pain in humans, Cerebral Cortex, doi: 10.1093/cercor/bhv043, modified

A momentary lapse of concentration is all it takes for a finger to become trapped or sprain an ankle - and it hurts. Pain is the body's protective mechanism and a complex neurological phenomenon. Moreover, ongoing pain in the sense of chronic pain can be a disease. Scientists from Technische Universität München (TUM) have now demonstrated that already during a few minutes of ongoing pain, the underlying brain activity changes by shifting from sensory to emotional processes.

In their experiments, Prof. Markus Ploner, Heisenberg Professor for Human Pain Research at the TUM School of Medicine, and his team investigated perception: How does the duration of pain or the action of a placebo affect activities in the brain? For their measurements they used electroencephalograms (EEGs). The test subject wore a cap with 64 electrodes that can measure nerve cell activity in the brain throughout the experiment. This method makes it possible to chronologically pinpoint which signals nerve cells use to respond to a pain stimulus.

Pain influences emotion

The scientists used the following arrangement for their experiments: Over a period of ten minutes, 41 participants in the study were given painful heat stimuli to the hand which varied in intensity throughout the duration of the experiment. The participants were asked to continuously assess the level of their pain on a scale of one to a hundred with the other hand using a slider.

"We were absolutely amazed by the results: After just a few minutes, the subjective perception of pain changed - for example, the subjects felt changes in pain when the objective stimulus remained unchanged. The sensation of pain became detached from the objective stimulus after just a few minutes," says Markus Ploner, describing the results.

Previous studies showed that brief pain stimuli are predominantly processed by sensory areas of the brain that process the signals from the sensory organs such as the skin. However, in their experiment with longer-lasting ongoing pain, the EEGs gave the scientists a different picture: in this case, emotional areas of the brain became active.

"If pain persists over a prolonged period of time, the associated brain activity shows that it changes from a pure perception process to a more emotional process. This realization is extremely interesting for the diagnosis and treatment of where pain persists for months and years," explains Markus Ploner, who is also senior physician in the Department of Neurology at the TUM Klinikum rechts der Isar.

Placebos change the perception of pain

A second experiment showed that it is not just the duration, but also the anticipation of a pain stimulus that affects perception. Twenty test subjects were initially given different intensities of painful laser pulses on two areas of the back of the hand. The participants then rated verbally how strong they perceived the pain stimuli. As the experiments progressed, the subjects were once again given the same stimuli, the difference this time being that two creams had previously been applied to both areas. Although neither cream contained an active substance, the subjects were told that one of the creams had a pain-relieving effect.

The result according to Markus Ploner: "The subjects assessed the pain on the skin area with the allegedly pain-relieving cream as significantly lower than on the other area of skin." The scientists were further able to demonstrate how the brain implements this placebo effect: although the subjects were given the same pain stimuli, the nerve cells in the second run triggered a different pattern of .

"Our results show how differently our brain processes the same pain stimuli. Systematically mapping and better understanding this complex neurological phenomenon of 'pain' in the is a big challenge, but is absolutely essential for improving therapeutic options for pain patients," in Ploner's opinion.

Explore further: 'Ouch zone' in the brain identified

More information: E. Schulz, E. S. May, M. Postorino, L. Tiemann, M. M. Nickel, V. Witkovsky, P. Schmidt, J. Gross, M. Ploner, Prefrontal gamma oscillations encode tonic pain in humans, Cerebral Cortex, February 2015. DOI: 10.1093/cercor/bhv043

L. Tiemann, E. S. May, M. Postorino, E. Schulz, M. M. Nickel, U. Bingel, M. Ploner, Differential neurophysiological correlates of bottom-up and top-down modulations of pain, Pain, 2015, Feb;156(2):289-96. DOI: 10.1097/01.j.pain.0000460309.94442.44

Related Stories

'Ouch zone' in the brain identified

March 9, 2015
Activity in a brain area known as the dorsal posterior insula is directly related to the intensity of pain, a brain imaging study of 17 people has found.

Fibromyalgia and the role of brain connectivity in pain inhibition

October 1, 2014
The cause of fibromyalgia, a chronic pain syndrome is not known. However, the results of a new study that compares brain activity in individuals with and without fibromyalgia indicate that decreased connectivity between pain-related ...

Various strategies used by patients with HIV, chronic pain

February 16, 2015
(HealthDay)—For individuals with HIV and chronic pain, various pain self-management strategies are employed, including physical activity, cognitive and spiritual strategies, and substance use, according to a study published ...

Scientists chart spinal circuitry responsible for chronic pain

December 5, 2014
Pain typically has a clear cause–but not always. When a person touches something hot or bumps into a sharp object, it's no surprise that it hurts. But for people with certain chronic pain disorders, including fibromyalgia ...

Pain from rejection and physical pain may not be so similar after all

November 18, 2014
Over the last decade, neuroscientists have largely come to believe that physical pain and social pain are processed by the brain in the same way. But a new study led by the University of Colorado shows that the two kinds ...

Experience of pain relies on multiple brain pathways, not just one

January 12, 2015
People's mindsets can affect their experience of pain. For example, a soldier in battle or an athlete in competition may report that an injury did not feel especially painful in the heat of the moment. But until now it has ...

Recommended for you

Research redefines proteins' role in the development of spinal sensory cells

September 19, 2017
A recent study led by Samantha Butler at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA has overturned a common belief about how a certain class of proteins in the spinal cord regulate ...

The brain at work: Spotting half-hidden objects

September 19, 2017
How does a driver's brain realize that a stop sign is behind a bush when only a red edge is showing? Or how can a monkey suspect that the yellow sliver in the leaves is a round piece of fruit?

Team discovers how to train damaging inflammatory cells to promote repair after stroke

September 19, 2017
White blood cells called neutrophils are like soldiers in your body that form in the bone marrow and at the first sign of microbial attack, head for the site of injury just as fast as they can to neutralize invading bacteria ...

Epileptic seizures show long-distance effects

September 19, 2017
The area in which an epileptic seizure starts in the brain, may be small but it reaches other parts of the brain at distances of over ten centimeters. That distant activity, in turn, influences the epileptic core, according ...

Study uncovers markers for severe form of multiple sclerosis

September 18, 2017
Scientists have uncovered two closely related cytokines—molecules involved in cell communication and movement—that may explain why some people develop progressive multiple sclerosis (MS), the most severe form of the disease. ...

Genetically altered mice bear some hallmarks of human bipolar behavior

September 18, 2017
Johns Hopkins researchers report they have genetically engineered mice that display many of the behavioral hallmarks of human bipolar disorder, and that the abnormal behaviors the rodents show can be reversed using well-established ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.