When pain is not only pain: Inserting needles into the body evokes distinct reward-related brain responses in the context of a treatment In-Seon Lee a,b , Christian Wallraven c , Jian Kong d , Dong-Seon Chang e , Hyejung Lee a , Hi-Joon Park a , Younbyoung Chae a,c, ⁎ a Acupuncture and Meridian Science Research Center, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea b Department of Internal Medicine: Psychosomatic Medicine and Psychotherapy, University Hospital Tübingen, Tübingen, Germany c Department of Brain Cognitive Engineering, Korea University, Seoul, Republic of Korea d Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA, USA e Department of Human Perception, Cognition and Action, Max Planck Institute for Biological Cybernetics, Tübingen, Germany HIGHLIGHTS • Acupuncture yielded greater brain activation in reward-related area in the context of treatment. • Inserting needles into the body in the context of treatment modulated pain responses in the brain. • Pain induced by therapeutic tools is modulated differently by the power of context in medical practice. abstract article info Article history: Received 11 July 2014 Received in revised form 12 December 2014 Accepted 16 December 2014 Available online 17 December 2014 Keywords: Acupuncture Context fMRI Pain Reward Therapeutic tool Ventral striatum The aim of this study was to compare behavioral and functional brain responses to the act of inserting needles into the body in two different contexts, treatment and stimulation, and to determine whether the behavioral and functional brain responses to a subsequent pain stimulus were also context dependent. Twenty-four partic- ipants were randomly divided into two groups: an acupuncture treatment (AT) group and an acupuncture stim- ulation (AS) group. Each participant received three different types of stimuli, consisting of tactile, acupuncture, and pain stimuli, and was given behavioral assessments during fMRI scanning. Although the applied stimuli were physically identical in both groups, the verbal instructions differed: participants in the AS group were primed to consider the acupuncture as a painful stimulus, whereas the participants in the AT group were told that the acupuncture was part of therapeutic treatment. Acupuncture yielded greater brain activation in reward-related brain areas (ventral striatum) of the brain in the AT group when compared to the AS group. Brain activation in response to pain stimuli was significantly attenuated in the bilateral secondary somatosensory cortex and the right dorsolateral prefrontal cortex after prior acupuncture needle stimulation in the AT group but not in the AS group. Inserting needles into the body in the context of treatment activated reward circuitries in the brain and modulated pain responses in the pain matrix. Our findings suggest that pain induced by therapeutic tools in the context of a treatment is modulated differently in the brain, demonstrating the power of context in medical practice. © 2014 Elsevier Inc. All rights reserved. 1. Introduction Pain, according to the International Association for the Study of Pain, is defined as ‘an unpleasant sensory and emotional experience associat- ed with actual or potential tissue damage, or described in terms of such damage’ [1]. Pain is considered a treatment target because of negative effects on patients' quality of life, including its role as a stressor on emo- tion and cognitive functions [2–4]. Pain impairs important cognitive functions by interrupting attention [5] and attenuating the value of re- wards [6]. Pain, usually opposed to reward, has generally been regarded as negative, with only a few exceptions in the context of supporting sur- vival. However, some recent research has emphasized the positive value of pain. Benedetti et al. [7] showed that participants produced greater pain tolerance when they informed that ischemic arm pain would be beneficial to the muscles, suggesting that pain could also be regarded as a reward when enduring pain was a benefit to participants. Leknes Physiology & Behavior 140 (2015) 148–155 ⁎ Corresponding author at: Acupuncture and Meridian Science Research Center, College of Korean Medicine, Kyung Hee University, 1 Hoegi-dong, Dongdaemun-gu, Seoul 130- 701, Republic of Korea. E-mail address: ybchae@khu.ac.kr (Y. Chae). http://dx.doi.org/10.1016/j.physbeh.2014.12.030 0031-9384/© 2014 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Physiology & Behavior journal homepage: www.elsevier.com/locate/phb