Subconscious learning shapes pain responses

May 22, 2015

In a new study led from Sweden's Karolinska Institutet, researchers report that people can be conditioned to associate images with particular pain responses - such as improved tolerance to pain - even when they are not consciously aware of the images. The findings are being published in the journal PNAS.

Previous studies have shown that a person's pain experience can be increased or decreased by associating a specific cue, such as an image, with high or low intensity pain. However, until now it has been unclear if it is necessary to be consciously aware of the cue in order to learn the association. In this recent study, Dr Karin Jensen and colleagues tested whether unconscious learning affected pain responses, by using subliminal images and training participants to associate a certain image with high pain and another image with low pain.

The study involved 49 participants in all, randomly assigned into four experimental groups that would elucidate the impact of different levels of conscious awareness during the experiment. All participants were generally healthy, with no chronic illnesses or psychiatric diagnoses. None of the participants reported receiving any medication apart from hormonal contraceptives.

In the experiment, images of different faces were presented on a computer screen. To some of the participants the images were shown so quickly that they could not be consciously recognized. For each image exposure, participants were subjected to pain stimulation and asked to rate the pain according to a specific scale. As each image was repeatedly associated with either high or low pain, it turned into a high pain cue or a low pain cue that would affect the participants' expectations.

The results suggest that pain cues could be learned without conscious awareness, as participants reported increased pain when shown the high pain image and reduced pain when shown the low pain image during identical levels of pain stimulation, regardless of whether or not the images were shown subliminally,

"These results demonstrate that pain responses can be shaped by learning that takes place outside conscious awareness, suggesting that unconscious learning may have an extensive effect on higher cognitive processes in general", says Karin Jensen.
-end-
This work was funded by the Osher Center for Integrative Medicine at Karolinska Institutet, and support was also provided by a NCCIH/NIH Grant. The study was conducted by researchers from the Osher Center at the Department of Clinical Neuroscience at Karolinska Institutet, Sweden and from Beth Israel Deaconess Medical Center and Harvard Medical School, USA.

Publication: 'Classical conditioning of analgesic and hyperalgesic pain responses without conscious awareness', Karin Jensen, Irving Kirsch, Sara Odmalm, Ted J. Kaptchuk, and Martin Ingvar, PNAS, published ahead of print May 15, 2015, doi:10.1073/pnas.1504567112.

Karolinska Instiutet -- a medical university: ki.se/english

Karolinska Institutet

Related Pain Articles from Brightsurf:

Pain researchers get a common language to describe pain
Pain researchers around the world have agreed to classify pain in the mouth, jaw and face according to the same system.

It's not just a pain in the head -- facial pain can be a symptom of headaches too
A new study finds that up to 10% of people with headaches also have facial pain.

New opioid speeds up recovery without increasing pain sensitivity or risk of chronic pain
A new type of non-addictive opioid developed by researchers at Tulane University and the Southeast Louisiana Veterans Health Care System accelerates recovery time from pain compared to morphine without increasing pain sensitivity, according to a new study published in the Journal of Neuroinflammation.

The insular cortex processes pain and drives learning from pain
Neuroscientists at EPFL have discovered an area of the brain, the insular cortex, that processes painful experiences and thereby drives learning from aversive events.

Pain, pain go away: new tools improve students' experience of school-based vaccines
Researchers at the University of Toronto and The Hospital for Sick Children (SickKids) have teamed up with educators, public health practitioners and grade seven students in Ontario to develop and implement a new approach to delivering school-based vaccines that improves student experience.

Pain sensitization increases risk of persistent knee pain
Becoming more sensitive to pain, or pain sensitization, is an important risk factor for developing persistent knee pain in osteoarthritis (OA), according to a new study by researchers from the Université de Montréal (UdeM) School of Rehabilitation and Hôpital Maisonneuve Rosemont Research Centre (CRHMR) in collaboration with researchers at Boston University School of Medicine (BUSM).

Becoming more sensitive to pain increases the risk of knee pain not going away
A new study by researchers in Montreal and Boston looks at the role that pain plays in osteoarthritis, a disease that affects over 300 million adults worldwide.

Pain disruption therapy treats source of chronic back pain
People with treatment-resistant back pain may get significant and lasting relief with dorsal root ganglion (DRG) stimulation therapy, an innovative treatment that short-circuits pain, suggests a study presented at the ANESTHESIOLOGY® 2018 annual meeting.

Sugar pills relieve pain for chronic pain patients
Someday doctors may prescribe sugar pills for certain chronic pain patients based on their brain anatomy and psychology.

Peripheral nerve block provides some with long-lasting pain relief for severe facial pain
A new study has shown that use of peripheral nerve blocks in the treatment of Trigeminal Neuralgia (TGN) may produce long-term pain relief.

Read More: Pain News and Pain Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.