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Pain Research and Management
Volume 2019, Article ID 6760121, 8 pages
https://doi.org/10.1155/2019/6760121
Review Article

Reward Processing under Chronic Pain from the Perspective of “Liking” and “Wanting”: A Narrative Review

1CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China
2Department of Psychology, University of Chinese Academy of Sciences, Beijing 100049, China

Correspondence should be addressed to Ning Wang; nc.ca.hcysp@ngnaw

Received 3 January 2019; Revised 6 March 2019; Accepted 4 April 2019; Published 21 April 2019

Academic Editor: Monika I. Hasenbring

Copyright © 2019 Xinhe Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Linked References

  1. L. T. S. Pina, D. N. Gouveia, J. S. Costa et al., “New perspectives for chronic pain treatment: a patent review (2010-2016),” Expert Opinion on Therapeutic Patents, vol. 27, no. 7, pp. 787–796, 2017. View at Publisher · View at Google Scholar · View at Scopus
  2. M. A. Ilgen, F. Kleinberg, R. V. Ignacio et al., “Noncancer pain conditions and risk of suicide,” JAMA Psychiatry, vol. 70, no. 7, pp. 692–697, 2013. View at Publisher · View at Google Scholar · View at Scopus
  3. J. D. Loeser, “Relieving pain in America,” The Clinical Journal of Pain, vol. 28, no. 3, pp. 185-186, 2012. View at Publisher · View at Google Scholar · View at Scopus
  4. H. Breivik, B. Collett, V. Ventafridda, R. Cohen, and D. Gallacher, “Survey of chronic pain in Europe: prevalence, impact on daily life, and treatment,” European Journal of Pain, vol. 10, no. 4, p. 287, 2006. View at Publisher · View at Google Scholar · View at Scopus
  5. W. Jackson, E. L. Zale, S. J. Berman et al., “Physical functioning and mindfulness skills training in chronic pain: a systematic review,” Journal of Pain Research, vol. 12, pp. 179–189, 2019. View at Publisher · View at Google Scholar
  6. W. Schultz, “Dopamine signals for reward value and risk: basic and recent data,” Behavioral and Brain Functions, vol. 6, no. 1, p. 24, 2010. View at Publisher · View at Google Scholar · View at Scopus
  7. D. H. Zald and M. T. Treadway, “Reward processing, neuroeconomics, and psychopathology,” Annual Review of Clinical Psychology, vol. 13, no. 1, pp. 471–495, 2017. View at Publisher · View at Google Scholar · View at Scopus
  8. A. E. Whitton, M. T. Treadway, and D. A. Pizzagalli, “Reward processing dysfunction in major depression, bipolar disorder and schizophrenia,” Current Opinion in Psychiatry, vol. 28, no. 1, pp. 7–12, 2015. View at Publisher · View at Google Scholar · View at Scopus
  9. P. Karoly, M. A. Okun, C. Enders, and H. Tennen, “Effects of pain intensity on goal schemas and goal pursuit: a daily diary study,” Health Psychology, vol. 33, no. 9, pp. 968–976, 2014. View at Publisher · View at Google Scholar · View at Scopus
  10. C. J. Mun, P. Karoly, and M. A. Okun, “Effects of daily pain intensity, positive affect, and individual differences in pain acceptance on work goal interference and progress,” Pain, vol. 156, no. 11, pp. 2276–2285, 2015. View at Publisher · View at Google Scholar · View at Scopus
  11. P. Geha, I. de Araujo, B. Green, and D. M. Small, “Decreased food pleasure and disrupted satiety signals in chronic low back pain,” Pain, vol. 155, no. 4, pp. 712–722, 2014. View at Publisher · View at Google Scholar · View at Scopus
  12. C. Chen, T. Takahashi, S. Nakagawa, T. Inoue, and I. Kusumi, “Reinforcement learning in depression: a review of computational research,” Neuroscience & Biobehavioral Reviews, vol. 55, pp. 247–267, 2015. View at Publisher · View at Google Scholar · View at Scopus
  13. S. J. Rizvi, D. A. Pizzagalli, B. A. Sproule, and S. H. Kennedy, “Assessing anhedonia in depression: potentials and pitfalls,” Neuroscience & Biobehavioral Reviews, vol. 65, pp. 21–35, 2016. View at Publisher · View at Google Scholar · View at Scopus
  14. L. Pizzagalli, C. E. Waugh, and I. H. Gotlib, “Anticipatory pleasure predicts motivation for reward in major depression,” Journal of Abnormal Psychology, vol. 121, no. 1, pp. 51–60, 2012. View at Publisher · View at Google Scholar · View at Scopus
  15. M. J. Robinson, A. M. Fischer, A. Ahuja, E. N. Lesser, and H. Maniates, “Roles of “wanting” and “liking” in motivating behavior: gambling, food, and drug addictions,” Behavioral Neuroscience of Motivation, vol. 27, pp. 105–136, 2016. View at Publisher · View at Google Scholar · View at Scopus
  16. W. Gandhi, S. Becker, and P. Schweinhardt, “Pain increases motivational drive to obtain reward, but does not affect associated hedonic responses: a behavioural study in healthy volunteers,” European Journal of Pain, vol. 17, no. 7, pp. 1093–1103, 2013. View at Publisher · View at Google Scholar · View at Scopus
  17. K. E. Darbor, H. C. Lench, and A. R. Carter-Sowell, “Do people eat the pain away? The effects of acute physical pain on subsequent consumption of sweet-tasting food,” PLoS One, vol. 11, no. 11, Article ID e0166931, 2016. View at Publisher · View at Google Scholar · View at Scopus
  18. D. M. Small and A. V. Apkarian, “Increased taste intensity perception exhibited by patients with chronic back pain,” Pain, vol. 120, no. 1-2, pp. 124–130, 2006. View at Publisher · View at Google Scholar · View at Scopus
  19. R. Nusslock and L. B. Alloy, “Reward processing and mood-related symptoms: an RDoC and translational neuroscience perspective,” Journal of Affective Disorders, vol. 216, pp. 3–16, 2017. View at Publisher · View at Google Scholar · View at Scopus
  20. R. Alloy and D. A. Pizzagalli, “Dysfunctional reward processing in depression,” Current Opinion in Psychology, vol. 4, pp. 114–118, 2015. View at Publisher · View at Google Scholar · View at Scopus
  21. J. J. Marbach and P. Lund, “Depression, anhedonia and anxiety in temporomandibular joint and other facial pain syndromes,” Pain, vol. 11, no. 1, pp. 73–84, 1981. View at Publisher · View at Google Scholar · View at Scopus
  22. J. J. Marbach, D. M. Richlin, and J. A. Lipton, “Illness behavior, depression and anhedonia in myofascial face and back pain patients,” Psychotherapy and Psychosomatics, vol. 39, no. 1, pp. 47–54, 1983. View at Publisher · View at Google Scholar · View at Scopus
  23. C. Carver and T. L. White, “Behavioral inhibition, behavioral activation, and affective responses to impending reward and punishment: the BIS/BAS Scales,” Journal of Personality and Social Psychology, vol. 67, no. 2, pp. 319–333, 1994. View at Publisher · View at Google Scholar
  24. J. A. Becerra-García and M. J. Robles Jurado, “Behavioral approach system activity and self-reported somatic symptoms in fibromyalgia: an exploratory study,” International Journal of Rheumatic Diseases, vol. 17, no. 1, pp. 89–92, 2014. View at Publisher · View at Google Scholar · View at Scopus
  25. N. A. Elvemo, N. I. Landrø, P. C. Borchgrevink, and A. K. Håberg, “Reward responsiveness in patients with chronic pain,” European Journal of Pain, vol. 19, no. 10, pp. 1537–1543, 2015. View at Publisher · View at Google Scholar · View at Scopus
  26. J. T. Landrø and J. B. Vancouver, “Goal constructs in psychology: structure, process, and content,” Psychological Bulletin, vol. 120, no. 3, pp. 338–375, 1996. View at Publisher · View at Google Scholar
  27. E. Vancouver and T. M. Palermo, “Goal pursuit in youth with chronic pain,” Children (Basel), vol. 3, no. 4, 2016. View at Publisher · View at Google Scholar
  28. N. Claes, J. W. S. Vlaeyen, E. Lauwerier, M. Meulders, and G. Crombez, “Goal conflict in chronic pain: day reconstruction method,” PeerJ, vol. 6, Article ID e5272, 2018. View at Publisher · View at Google Scholar · View at Scopus
  29. E. Fisher, E. Keogh, and C. Eccleston, “Adolescentsʼ approach-avoidance behaviour in the context of pain,” Pain, vol. 157, no. 2, pp. 370–376, 2016. View at Publisher · View at Google Scholar · View at Scopus
  30. A. H. Threadgill and P. A. Gable, “The sweetness of successful goal pursuit: approach-motivated pregoal states enhance the reward positivity during goal pursuit,” International Journal of Psychophysiology, vol. 132, pp. 277–286, 2018. View at Publisher · View at Google Scholar · View at Scopus
  31. A. H. Threadgill and P. A. Gable, “Approach-motivated pregoal states enhance the reward positivity,” Psychophysiology, vol. 53, no. 5, pp. 733–738, 2016. View at Publisher · View at Google Scholar · View at Scopus
  32. J. K. Hardy, L. J. Crofford, and S. C. Segerstrom, “Goal conflict, distress, and pain in women with fibromyalgia: a daily diary study,” Journal of Psychosomatic Research, vol. 70, no. 6, pp. 534–540, 2011. View at Publisher · View at Google Scholar · View at Scopus
  33. K. C. Berridge, “The debate over dopamine’s role in reward: the case for incentive salience,” Psychopharmacology, vol. 191, no. 3, pp. 391–431, 2007. View at Publisher · View at Google Scholar · View at Scopus
  34. K. C. Berridge, T. E. Robinson, and J. W. Aldridge, “Dissecting components of reward: “liking,” “wanting,” and learning,” Current Opinion in Pharmacology, vol. 9, no. 1, pp. 65–73, 2009. View at Publisher · View at Google Scholar · View at Scopus
  35. R. A. Wise, “Dopamine and reward: the anhedonia hypothesis 30 years on,” Neurotoxicity Research, vol. 14, no. 2-3, pp. 169–183, 2008. View at Publisher · View at Google Scholar · View at Scopus
  36. K. C. Berridge and T. E. Robinson, “What is the role of dopamine in reward: hedonic impact, reward learning, or incentive salience?” Brain Research Reviews, vol. 28, no. 3, pp. 309–369, 1998. View at Publisher · View at Google Scholar · View at Scopus
  37. T. E. Robinson and K. C. Berridge, “Addiction,” Annual Review of Psychology, vol. 54, no. 1, pp. 25–53, 2003. View at Publisher · View at Google Scholar · View at Scopus
  38. M. Cabanac, “Physiological role of pleasure,” Science, vol. 173, no. 4002, pp. 1103–1107, 1971. View at Publisher · View at Google Scholar · View at Scopus
  39. R. A. Wise, “Dopamine, learning and motivation,” Nature Reviews Neuroscience, vol. 5, no. 6, pp. 483–494, 2004. View at Publisher · View at Google Scholar · View at Scopus
  40. E. Pool, V. Sennwald, S. Delplanque, T. Brosch, and D. Sander, “Measuring wanting and liking from animals to humans: a systematic review,” Neuroscience & Biobehavioral Reviews, vol. 63, pp. 124–142, 2016. View at Publisher · View at Google Scholar · View at Scopus
  41. S. Robinson, S. M. Sandstrom, V. H. Sandstrom, and R. D. Palmiter, “Distinguishing whether dopamine regulates liking, wanting, and/or learning about rewards,” Behavioral Neuroscience, vol. 119, no. 1, pp. 5–15, 2005. View at Publisher · View at Google Scholar · View at Scopus
  42. K. C. Berridge, “Food reward: brain substrates of wanting and liking,” Neuroscience & Biobehavioral Reviews, vol. 20, no. 1, pp. 1–25, 1996. View at Publisher · View at Google Scholar · View at Scopus
  43. D. C. Castro and K. C. Berridge, “Opioid hedonic hotspot in nucleus accumbens shell: mu, delta, and kappa maps for enhancement of sweetness “liking” and “wanting”,” Journal of Neuroscience, vol. 34, no. 12, pp. 4239–4250, 2014. View at Publisher · View at Google Scholar · View at Scopus
  44. S. E. Ross, E. Levin, C. A. Itoga, C. B. Schoen, R. Selmane, and J. W. Aldridge, “Deep brain stimulation in the central nucleus of the amygdala decreases “wanting” and “liking” of food rewards,” European Journal of Neuroscience, vol. 44, no. 7, pp. 2431–2445, 2016. View at Publisher · View at Google Scholar · View at Scopus
  45. J. W. de Jong, T. J. M. Roelofs, F. M. U. Mol et al., “Reducing ventral tegmental dopamine D2 receptor expression selectively boosts incentive motivation,” Neuropsychopharmacology, vol. 40, no. 9, pp. 2085–2095, 2015. View at Publisher · View at Google Scholar · View at Scopus
  46. S. L. Robinson and B. A. McCool, “Microstructural analysis of rat ethanol and water drinking patterns using a modified operant self-administration model,” Physiology & Behavior, vol. 149, pp. 119–130, 2015. View at Publisher · View at Google Scholar · View at Scopus
  47. D. C. Castro and K. C. Berridge, “Opioid and orexin hedonic hotspots in rat orbitofrontal cortex and insula,” Proceedings of the National Academy of Sciences, vol. 114, no. 43, pp. 9125–9134, 2017. View at Publisher · View at Google Scholar · View at Scopus
  48. S. Peciña, B. Cagniard, K. C. Berridge, J. W. Aldridge, and X. Zhuang, “Hyperdopaminergic mutant mice have higher “wanting” but not “liking” for sweet rewards,” The Journal of Neuroscience, vol. 23, no. 28, pp. 9395–9402, 2003. View at Publisher · View at Google Scholar
  49. A. Dellarole, P. Morton, R. Brambilla et al., “Neuropathic pain-induced depressive-like behavior and hippocampal neurogenesis and plasticity are dependent on TNFR1 signaling,” Brain, Behavior, and Immunity, vol. 41, pp. 65–81, 2014. View at Publisher · View at Google Scholar · View at Scopus
  50. J. Wang, Y. Goffer, D. Xu et al., “A single subanesthetic dose of ketamine relieves depression-like behaviors induced by neuropathic pain in rats,” Anesthesiology, vol. 115, no. 4, pp. 812–821, 2011. View at Publisher · View at Google Scholar · View at Scopus
  51. J. Wu, Z. Zhao, B. Sabirzhanov et al., “Spinal cord injury causes brain inflammation associated with cognitive and affective changes: role of cell cycle pathways,” Journal of Neuroscience, vol. 34, no. 33, pp. 10989–11006, 2014. View at Publisher · View at Google Scholar · View at Scopus
  52. A. S. Bura, T. Guegan, D. Zamanillo, J. M. Vela, and R. Maldonado, “Operant self-administration of a sigma ligand improves nociceptive and emotional manifestations of neuropathic pain,” European Journal of Pain, vol. 17, no. 6, pp. 832–843, 2013. View at Publisher · View at Google Scholar · View at Scopus
  53. Y.-T. Liu, Y.-W. Shao, C.-T. Yen, and F.-Z. Shaw, “Acid-induced hyperalgesia and anxio-depressive comorbidity in rats,” Physiology & Behavior, vol. 131, pp. 105–110, 2014. View at Publisher · View at Google Scholar · View at Scopus
  54. M. Shi, W.-J. Qi, G. Gao, J.-Y. Wang, and F. Luo, “Increased thermal and mechanical nociceptive thresholds in rats with depressive-like behaviors,” Brain Research, vol. 1353, pp. 225–233, 2010. View at Publisher · View at Google Scholar · View at Scopus
  55. M. Shi, J.-Y. Wang, and F. Luo, “Depression shows divergent effects on evoked and spontaneous pain behaviors in rats,” The Journal of Pain, vol. 11, no. 3, pp. 219–229, 2010. View at Publisher · View at Google Scholar · View at Scopus
  56. C. Su, J. D’amour, M. Lee et al., “Persistent pain alters AMPA receptor subunit levels in the nucleus accumbens,” Molecular Brain, vol. 8, p. 46, 2015. View at Publisher · View at Google Scholar · View at Scopus
  57. R. Urban, G. Scherrer, E. H. Goulding, L. H. Tecott, and A. I. Basbaum, “Behavioral indices of ongoing pain are largely unchanged in male mice with tissue or nerve injury-induced mechanical hypersensitivity,” Pain, vol. 152, no. 5, pp. 990–1000, 2011. View at Publisher · View at Google Scholar · View at Scopus
  58. L. Bravo, J. A. Mico, R. Rey-Brea, B. Pérez-Nievas, J. C. Leza, and E. Berrocoso, “Depressive-like states heighten the aversion to painful stimuli in a rat model of comorbid chronic pain and depression,” Anesthesiology, vol. 117, no. 3, pp. 613–625, 2012. View at Publisher · View at Google Scholar · View at Scopus
  59. Y. Goffer, D. Xu, S. E. Eberle et al., “Calcium-permeable AMPA receptors in the nucleus accumbens regulate depression-like behaviors in the chronic neuropathic pain state,” Journal of Neuroscience, vol. 33, no. 48, pp. 19034–19044, 2013. View at Publisher · View at Google Scholar · View at Scopus
  60. A. Okun, D. L. McKinzie, J. M. Witkin et al., “Hedonic and motivational responses to food reward are unchanged in rats with neuropathic pain,” Pain, vol. 157, no. 12, pp. 2731–2738, 2016. View at Publisher · View at Google Scholar · View at Scopus
  61. N. Schwartz, P. Temkin, S. Jurado et al., “Decreased motivation during chronic pain requires long-term depression in the nucleus accumbens,” Science, vol. 345, no. 6196, pp. 535–542, 2014. View at Publisher · View at Google Scholar · View at Scopus
  62. L. Hipolito, A. Wilson-Poe, Y. Campos-Jurado et al., “Inflammatory pain promotes increased opioid self-administration: role of dysregulated ventral tegmental area opioid receptors,” Journal of Neuroscience, vol. 35, no. 35, pp. 12217–12231, 2015. View at Publisher · View at Google Scholar · View at Scopus
  63. N. Schwartz, C. Miller, and H. L. Fields, “Cortico-Accumbens regulation of approach-avoidance behavior is modified by experience and chronic pain,” Cell Reports, vol. 19, no. 8, pp. 1522–1531, 2017. View at Publisher · View at Google Scholar · View at Scopus
  64. D. Amorim, A. David-Pereira, A. Pertovaara, A. Almeida, and F. Pinto-Ribeiro, “Amitriptyline reverses hyperalgesia and improves associated mood-like disorders in a model of experimental monoarthritis,” Behavioural Brain Research, vol. 265, pp. 12–21, 2014. View at Publisher · View at Google Scholar · View at Scopus
  65. W. Hodos, “Progressive ratio as a measure of reward strength,” Science, vol. 134, no. 3483, pp. 943-944, 1961. View at Publisher · View at Google Scholar · View at Scopus
  66. S. Peciña and K. C. Berridge, “Dopamine or opioid stimulation of nucleus accumbens similarly amplify cue-triggered “wanting” for reward: entire core and medial shell mapped as substrates for PIT enhancement,” European Journal of Neuroscience, vol. 37, no. 9, pp. 1529–1540, 2013. View at Publisher · View at Google Scholar · View at Scopus
  67. C. M. Cannon and R. D. Palmiter, “Reward without dopamine,” The Journal of Neuroscience, vol. 23, no. 34, pp. 10827–10831, 2003. View at Publisher · View at Google Scholar
  68. K. S. Smith, K. C. Berridge, and J. W. Aldridge, “Disentangling pleasure from incentive salience and learning signals in brain reward circuitry,” Proceedings of the National Academy of Sciences, vol. 108, no. 27, pp. E255–E264, 2011. View at Publisher · View at Google Scholar · View at Scopus
  69. M. Narita, Y. Kishimoto, Y. Ise, Y. Yajima, K. Misawa, and T. Suzuki, “Direct evidence for the involvement of the mesolimbic κ-opioid system in the morphine-induced rewarding effect under an inflammatory pain-like state,” Neuropsychopharmacology, vol. 30, no. 1, pp. 111–118, 2005. View at Publisher · View at Google Scholar · View at Scopus
  70. S. Ozaki, M. Narita, M. Narita et al., “Suppression of the morphine-induced rewarding effect in the rat with neuropathic pain: implication of the reduction in μ-opioid receptor functions in the ventral tegmental area,” Journal of Neurochemistry, vol. 82, no. 5, pp. 1192–1198, 2002. View at Publisher · View at Google Scholar · View at Scopus
  71. K. Niikura, M. Narita, M. Narita et al., “Direct evidence for the involvement of endogenous β-endorphin in the suppression of the morphine-induced rewarding effect under a neuropathic pain-like state,” Neuroscience Letters, vol. 435, no. 3, pp. 257–262, 2008. View at Publisher · View at Google Scholar · View at Scopus
  72. R. E. Harris, D. J. Clauw, D. J. Scott, S. A. McLean, R. H. Gracely, and J.-K. Zubieta, “Decreased central-opioid receptor availability in fibromyalgia,” Journal of Neuroscience, vol. 27, no. 37, pp. 10000–10006, 2007. View at Publisher · View at Google Scholar · View at Scopus
  73. A. Schrepf, D. E. Harper, S. E. Harte et al., “Endogenous opioidergic dysregulation of pain in fibromyalgia,” Pain, vol. 157, no. 10, pp. 2217–2225, 2016. View at Publisher · View at Google Scholar · View at Scopus
  74. I. Tsutsui-Kimura, H. Takiue, K. Yoshida et al., “Dysfunction of ventrolateral striatal dopamine receptor type 2-expressing medium spiny neurons impairs instrumental motivation,” Nature Communications, vol. 8, p. 14304, 2017. View at Publisher · View at Google Scholar · View at Scopus
  75. I. K. Martikainen, E. B. Nuechterlein, M. Pecina et al., “Chronic back pain is associated with alterations in dopamine neurotransmission in the ventral striatum,” Journal of Neuroscience, vol. 35, no. 27, pp. 9957–9965, 2015. View at Publisher · View at Google Scholar · View at Scopus
  76. D. S. Albrecht, P. J. MacKie, D. A. Kareken et al., “Differential dopamine function in fibromyalgia,” Brain Imaging and Behavior, vol. 10, no. 3, pp. 829–839, 2016. View at Publisher · View at Google Scholar · View at Scopus
  77. G. Crombez, D. M. L. Ryckeghem, C. Van Ryckeghem, and S. Van Damme, “Attentional bias to pain-related information: a meta-analysis,” Pain, vol. 154, no. 4, pp. 497–510, 2013. View at Publisher · View at Google Scholar · View at Scopus
  78. C. Berryman, T. R. Stanton, J. K. Bowering, A. Tabor, A. McFarlane, and L. G. Moseley, “Evidence for working memory deficits in chronic pain: a systematic review and meta-analysis,” Pain, vol. 154, no. 8, pp. 1181–1196, 2013. View at Publisher · View at Google Scholar · View at Scopus
  79. M. A. Farmer, A. Leja, E. Foxen-Craft et al., “Pain reduces sexual motivation in female but not male mice,” Journal of Neuroscience, vol. 34, no. 17, pp. 5747–5753, 2014. View at Publisher · View at Google Scholar · View at Scopus
  80. J. Luo, T. Wang, S. Liang, X. Hu, W. Li, and F. Jin, “Experimental gastritis leads to anxiety- and depression-like behaviors in female but not male rats,” Behavioral and Brain Functions, vol. 9, no. 1, p. 46, 2013. View at Publisher · View at Google Scholar · View at Scopus
  81. K. K. Pitchers, S. B. Flagel, E. G. O’Donnell, L. C. Solberg Woods, M. Sarter, and T. E. Robinson, “Individual variation in the propensity to attribute incentive salience to a food cue: influence of sex,” Behavioural Brain Research, vol. 278, pp. 462–469, 2015. View at Publisher · View at Google Scholar · View at Scopus
  82. R. M. Craft, J. S. Mogil, and A. M. Aloisi, “Sex differences in pain and analgesia: the role of gonadal hormones,” European Journal of Pain, vol. 8, no. 5, pp. 397–411, 2004. View at Publisher · View at Google Scholar · View at Scopus
  83. O. van Hecke, N. Torrance, and B. H. Smith, “Chronic pain epidemiology and its clinical relevance,” British Journal of Anaesthesia, vol. 111, no. 1, pp. 13–18, 2013. View at Publisher · View at Google Scholar · View at Scopus