Placebo and Nocebo Effects Are Defined by Opposite Opioid and Dopaminergic Responses
Abstract
CONTEXT: Placebo and nocebo effects, the therapeutic and adverse effects, respectively, of inert substances or sham procedures, represent serious confounds in the evaluation of therapeutic interventions. They are also an example of cognitive processes, particularly expectations, capable of influencing physiology. OBJECTIVE: To examine the contribution of 2 different neurotransmitters, the endogenous opioid and the dopaminergic (DA) systems, to the development of placebo and nocebo effects. DESIGN AND SETTING: Using a within-subject design, subjects twice underwent a 20-minute standardized pain challenge, in the absence and presence of a placebo with expected analgesic properties. Studies were conducted in a university hospital setting. PARTICIPANTS: Twenty healthy men and women aged 20 to 30 years recruited by advertisement. MAIN OUTCOME MEASURES: Activation of DA and opioid neurotransmission by a pain stressor with and without placebo (changes in the binding potential of carbon 11 [11C]-labeled raclopride and [11C] carfentanil with positron emission tomography) and ratings of pain, affective state, and anticipation and perception of analgesia. RESULTS: Placebo-induced activation of opioid neurotransmission was detected in the anterior cingulate, orbitofrontal and insular cortices, nucleus accumbens, amygdala, and periaqueductal gray matter. Dopaminergic activation was observed in the ventral basal ganglia, including the nucleus accumbens. Regional DA and opioid activity were associated with the anticipated and subjectively perceived effectiveness of the placebo and reductions in continuous pain ratings. High placebo responses were associated with greater DA and opioid activity in the nucleus accumbens. Nocebo responses were associated with a deactivation of DA and opioid release. Nucleus accumbens DA release accounted for 25% of the variance in placebo analgesic effects. CONCLUSIONS: Placebo and nocebo effects are associated with opposite responses of DA and endogenous opioid neurotransmission in a distributed network of regions. The brain areas involved in these phenomena form part of the circuit typically implicated in reward responses and motivated behavior.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
Placebo responses are associated with the release of dopamine and endogenous opioids, whereas nocebo responses are associated with the release of cholecystokinin.
“Placebo and nocebo responses are also associated with different neurotransmitters; placebo responses are associated with the release of dopamine and endogenous opioids, whereas nocebo responses are associated with the release of cholecystokinin32–34.”
From Boundary effects of expectation in human pain perception (2019) · cites this paper as [32]
Mesolimbic dopamine projections from VTA to NAc are important in analgesic effects induced by placebo and stress, pain relief, and changes in motivated behavior caused by chronic pain.
“mesolimbic dopamine projections from the ventral tegmental area (VTA) to the NAc are important in the analgesic effects induced by placebo and stress [55],[82], pain relief [58],[83], and the changes in motivated behavior caused by chronic pain [84].”
From Distinct Brain Systems Mediate the Effects of Nociceptive Input and Self-Regulation on Pain (2015) · cites this paper as [82]
Analgesic placebo effects are mediated by the co-activation of DA and opioid neurotransmission in the ventral striatum (including the nucleus accumbens).
“Furthermore, analgesic placebo effects are mediated by the co-activation of DA and opioid neurotransmission in the ventral striatum (including the nucleus accumbens) (63), highlighting the potential interactions between DA and EO in the mesolimbic reward circuitry.”
From Neuroendocrinology of Parental Response to Baby‐Cry (2011) · cites this paper as [63]
Using PET techniques, μ-opioid neurotransmission induced by analgesic cognitive expectations, known as placebo effects, are enhanced in the orbital frontal cortex, dorsal and rostral anterior cingulate cortex, nucleus accumbens and midbrain.
“Using PET techniques, μ-opioid neurotransmission induced by the analgesic cognitive expectations, known as placebo effects, are enhanced in the orbital frontal cortex, dorsal and rostral anterior cingulate cortex, nucleus accumbems and midbrain (63,64).”
From Neuroendocrinology of Parental Response to Baby‐Cry (2011) · cites this paper as [63]
Cites
Prospect Theory: An Analysis of Decision under Risk
Kahneman, D., & Tversky, A. (1979) · Econometrica · doi:10.2307/1914185 · Cited by 48,524 · see citing works
Development and validation of brief measures of positive and negative affect: The PANAS scales.
Watson, D., Clark, L. A., & Tellegen, A. (1988) · Journal of Personality and Social Psychology · doi:10.1037/0022-3514.54.6.1063 · Cited by 32,433 · see citing works
Neurophysiological investigation of the basis of the fMRI signal
Logothetis, N. K., Pauls, J., Augath, M., Trinath, T., & Oeltermann, A. (2001) · Nature · doi:10.1038/35084005 · Cited by 6,542 · see citing works
What is the role of dopamine in reward: hedonic impact, reward learning, or incentive salience?
Berridge, K. C., & Robinson, T. E. (1998) · Brain Research Reviews · doi:10.1016/s0165-0173(98)00019-8 · Cited by 4,127 · see citing works
Behavioral Theories and the Neurophysiology of Reward
Schultz, W. (2006) · Annual Review of Psychology · doi:10.1146/annurev.psych.56.091103.070229 · Cited by 1,637 · see citing works
Adaptive Coding of Reward Value by Dopamine Neurons
Tobler, P. N., Fiorillo, C. D., & Schultz, W. (2005) · Science · doi:10.1126/science.1105370 · Cited by 1,276 · see citing works
Distributed Neural Representation of Expected Value
Knutson, B., Taylor, J., Kaufman, M., Peterson, R., & Glover, G. (2005) · The Journal of Neuroscience · doi:10.1523/jneurosci.0642-05.2005 · Cited by 955 · see citing works
State-dependent opioid control of pain
Fields, H. (2004) · Nature Reviews Neuroscience · doi:10.1038/nrn1431 · Cited by 946 · see citing works
Placebo Effects Mediated by Endogenous Opioid Activity on μ-Opioid Receptors
Zubieta, J.-K., Bueller, J. A., Jackson, L. R., Scott, D. J., Xu, Y., Koeppe, R. A., Nichols, T. E., & Stohler, C. S. (2005) · The Journal of Neuroscience · doi:10.1523/jneurosci.0439-05.2005 · Cited by 779 · see citing works
Self-citationDecision Affect Theory: Emotional Reactions to the Outcomes of Risky Options
Mellers, B. A., Schwartz, A., Ho, K., & Ritov, I. (1997) · Psychological Science · doi:10.1111/j.1467-9280.1997.tb00455.x · Cited by 736 · see citing works
Placebo effects on human μ-opioid activity during pain
Wager, T. D., Scott, D. J., & Zubieta, J.-K. (2007) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.0702413104 · Cited by 562 · see citing works
Self-citationPetrovic, P., Dietrich, T., Fransson, P., Andersson, J., Carlsson, K., & Ingvar, M. (2005) · Neuron · doi:10.1016/j.neuron.2005.05.023 · Cited by 437 · see citing works
Volkow, N. D., Wang, G.-J., Ma, Y., Fowler, J. S., Zhu, W., Maynard, L., Telang, F., Vaska, P., Ding, Y.-S., Wong, C., et al. (2003) · The Journal of Neuroscience · doi:10.1523/jneurosci.23-36-11461.2003 · Cited by 302 · see citing works
Selective Opiate Modulation of Nociceptive Processing in the Human Brain
Casey, K. L., Svensson, P., Morrow, T. J., Raz, J., Jone, C., & Minoshima, S. (2000) · Journal of Neurophysiology · doi:10.1152/jn.2000.84.1.525 · Cited by 186 · see citing works
Borras, M. C., Becerra, L., Ploghaus, A., Gostic, J. M., DaSilva, A., Gonzalez, R. G., & Borsook, D. (2004) · Journal of Neurophysiology · doi:10.1152/jn.00249.2003 · Cited by 118 · see citing works
Functional brain imaging of placebo analgesia: methodological challenges and recommendations
Rainville, P., & Duncan, G. H. (2006) · Pain · doi:10.1016/j.pain.2006.01.011 · Cited by 26 · cited 2× · see citing works
“In this context, minimizing differences in the pain experience between conditions could have resulted in lesser effects and differences between control and placebo studies.(19) It has also been hypothesized that placebo effects represent a form of reward expectation processing.”
Background
Flagged first, then by citations
Cited by
Sorted by citations
The brain reward circuitry in mood disorders
Russo, S. J., & Nestler, E. J. (2013) · Nature Reviews Neuroscience · doi:10.1038/nrn3381 · Cited by 1,870 · see citing works
Activation of the Opioidergic Descending Pain Control System Underlies Placebo Analgesia
Eippert, F., Bingel, U., Schoell, E. D., Yacubian, J., Klinger, R., Lorenz, J., & Büchel, C. (2009) · Neuron · doi:10.1016/j.neuron.2009.07.014 · Cited by 839 · see citing works
The neuroscience of placebo effects: connecting context, learning and health
Wager, T. D., & Atlas, L. Y. (2015) · Nature Reviews Neuroscience · doi:10.1038/nrn3976 · Cited by 844 · see citing works
The placebo response in medicine: minimize, maximize or personalize?
Enck, P., Bingel, U., Schedlowski, M., & Rief, W. (2013) · Nature Reviews Drug Discovery · doi:10.1038/nrd3923 · Cited by 671 · see citing works
Getting the pain you expect: mechanisms of placebo, nocebo and reappraisal effects in humans
Tracey, I. (2010) · Nature Medicine · doi:10.1038/nm.2229 · Cited by 553 · see citing works
Placebo Analgesia: A Predictive Coding Perspective
Büchel, C., Geuter, S., Sprenger, C., & Eippert, F. (2014) · Neuron · doi:10.1016/j.neuron.2014.02.042 · Cited by 505 · see citing works
Placebo and the New Physiology of the Doctor-Patient Relationship
Benedetti, F. (2013) · Physiological Reviews · doi:10.1152/physrev.00043.2012 · Cited by 492 · see citing works
Atlas, L. Y., & Wager, T. D. (2012) · Neuroscience Letters · doi:10.1016/j.neulet.2012.03.039 · Cited by 463 · see citing works
How Placebos Change the Patient's Brain
Benedetti, F., Carlino, E., & Pollo, A. (2011) · Neuropsychopharmacology · doi:10.1038/npp.2010.81 · Cited by 446 · see citing works
Brain mediators of predictive cue effects on perceived pain
Atlas, L. Y., Bolger, N., Lindquist, M. A., & Wager, T. D. (2010) · The Journal of Neuroscience · doi:10.1523/jneurosci.0057-10.2010 · Cited by 389 · see citing works
Fear is only as deep as the mind allows
Diekhof, E. K., Geier, K., Falkai, P., & Gruber, O. (2011) · NeuroImage · doi:10.1016/j.neuroimage.2011.05.073 · Cited by 413 · see citing works
Mithoefer, M. C., Feduccia, A. A., Jerome, L., Mithoefer, A., Wagner, M., Walsh, Z., Hamilton, S., Yazar-Klosinski, B., Emerson, A., & Doblin, R. (2019) · Psychopharmacology · doi:10.1007/s00213-019-05249-5 · Cited by 359 · see citing works
RetractedBorsook, D., Upadhyay, J., Chudler, E. H., & Becerra, L. (2010) · Molecular Pain · doi:10.1186/1744-8069-6-27 · Cited by 326 · see citing works
Wager, T. D., Atlas, L. Y., Leotti, L. A., & Rilling, J. K. (2011) · The Journal of Neuroscience · doi:10.1523/jneurosci.3420-10.2011 · Cited by 328 · see citing works
How placebo responses are formed: a learning perspective
Colloca, L., & Miller, F. G. (2011) · Philosophical Transactions of the Royal Society B: Biological Sciences · doi:10.1098/rstb.2010.0398 · Cited by 323 · see citing works
Schedlowski, M., Enck, P., Rief, W., & Bingel, U. (2015) · Pharmacological Reviews · doi:10.1124/pr.114.009423 · Cited by 323 · see citing works
Common brain mechanisms of chronic pain and addiction
Elman, I., & Borsook, D. (2016) · Neuron · doi:10.1016/j.neuron.2015.11.027 · Cited by 303 · see citing works
Harris, R. E., Zubieta, J.-K., Scott, D. J., Napadow, V., Gracely, R. H., & Clauw, D. J. (2009) · NeuroImage · doi:10.1016/j.neuroimage.2009.05.083 · Cited by 296 · see citing works
Self-citationNeurobiological Mechanisms of Placebo Responses
Zubieta, J., & Stohler, C. S. (2009) · Annals of the New York Academy of Sciences · doi:10.1111/j.1749-6632.2009.04424.x · Cited by 277 · see citing works
Self-citationActivation of the reward system boosts innate and adaptive immunity
Ben-Shaanan, T. L., Azulay-Debby, H., Dubovik, T., Starosvetsky, E., Korin, B., Schiller, M., Green, N. L., Admon, Y., Hakim, F., Shen-Orr, S. S., et al. (2016) · Nature Medicine · doi:10.1038/nm.4133 · Cited by 272 · see citing works
A functional magnetic resonance imaging study on the neural mechanisms of hyperalgesic nocebo effect
Kong, J., Gollub, R. L., Polich, G., Kirsch, I., LaViolette, P., Vangel, M., Rosen, B., & Kaptchuk, T. J. (2008) · The Journal of Neuroscience · doi:10.1523/jneurosci.2944-08.2008 · Cited by 263 · see citing works
Distinct Brain Systems Mediate the Effects of Nociceptive Input and Self-Regulation on Pain
Woo, C.-W., Roy, M., Buhle, J. T., & Wager, T. D. (2015) · PLoS Biology · doi:10.1371/journal.pbio.1002036 · Cited by 263 · see citing works
Placebo analgesia: Psychological and neurobiological mechanisms
Colloca, L., Klinger, R., Flor, H., & Bingel, U. (2013) · Pain · doi:10.1016/j.pain.2013.02.002 · Cited by 263 · see citing works
Lessons in exercise neurobiology: the case of endorphins.
Dishman, R. K., & O'Connor, P. J. (2009) · Mental health and physical activity · doi:10.1016/j.mhpa.2009.01.002 · Cited by 243 · see citing works
Relieving patients' pain with expectation interventions: a meta-analysis
Peerdeman, K. J., van Laarhoven, A. I. M., Keij, S. M., Vase, L., Rovers, M. M., Peters, M. L., & Evers, A. W. M. (2016) · Pain · doi:10.1097/j.pain.0000000000000540 · Cited by 239 · see citing works
Pain and analgesia: the value of salience circuits
Borsook, D., Edwards, R., Elman, I., Becerra, L., & Levine, J. (2013) · Progress in Neurobiology · doi:10.1016/j.pneurobio.2013.02.003 · Cited by 215 · see citing works
Schweinhardt, P., Seminowicz, D. A., Jaeger, E., Duncan, G. H., & Bushnell, M. C. (2009) · The Journal of Neuroscience · doi:10.1523/jneurosci.5634-08.2009 · Cited by 210 · see citing works
Amanzio, M., Benedetti, F., Porro, C. A., Palermo, S., & Cauda, F. (2013) · Human Brain Mapping · doi:10.1002/hbm.21471 · Cited by 202 · see citing works
Interactions between brain and spinal cord mediate value effects in nocebo hyperalgesia
Tinnermann, A., Geuter, S., Sprenger, C., Finsterbusch, J., & Büchel, C. (2017) · Science · doi:10.1126/science.aan1221 · Cited by 208 · see citing works
Gut memories: Towards a cognitive neurobiology of irritable bowel syndrome
Kennedy, P. J., Clarke, G., Quigley, E. M. M., Groeger, J. A., Dinan, T. G., & Cryan, J. F. (2012) · Neuroscience & Biobehavioral Reviews · doi:10.1016/j.neubiorev.2011.07.001 · Cited by 193 · see citing works
Pain, decisions, and actions: a motivational perspective
Wiech, K., & Tracey, I. (2013) · Frontiers in Neuroscience · doi:10.3389/fnins.2013.00046 · Cited by 188 · see citing works
Top-Down Dysregulation—From ADHD to Emotional Instability
Petrovic, P., & Castellanos, F. X. (2016) · Frontiers in Behavioral Neuroscience · doi:10.3389/fnbeh.2016.00070 · Cited by 179 · see citing works
The placebo effect: advances from different methodological approaches
Meissner, K., Bingel, U., Colloca, L., Wager, T. D., Watson, A., & Flaten, M. A. (2011) · The Journal of Neuroscience · doi:10.1523/jneurosci.4099-11.2011 · Cited by 178 · see citing works
Opioid system and human emotions
Nummenmaa, L., & Tuominen, L. (2018) · British Journal of Pharmacology · doi:10.1111/bph.13812 · Cited by 178 · see citing works
Placebo effects and their determinants in gastrointestinal disorders
Elsenbruch, S., & Enck, P. (2015) · Nature Reviews Gastroenterology & Hepatology · doi:10.1038/nrgastro.2015.117 · Cited by 173 · see citing works
Neural bases of conditioned placebo analgesia
Lui, F., Colloca, L., Duzzi, D., Anchisi, D., Benedetti, F., & Porro, C. A. (2010) · Pain · doi:10.1016/j.pain.2010.09.021 · Cited by 149 · see citing works
“Individual differences in the magnitude of opioids [50] and dopamine [43] release following placebo manipulations have also been described in the literature.”
BackgroundFacilitation of Pain in the Human Spinal Cord by Nocebo Treatment
Geuter, S., & Büchel, C. (2013) · The Journal of Neuroscience · doi:10.1523/jneurosci.2191-13.2013 · Cited by 152 · see citing works
Nocebo and pain: an overview of the psychoneurobiological mechanisms
Blasini, M., Corsi, N., Klinger, R., & Colloca, L. (2017) · PAIN Reports · doi:10.1097/pr9.0000000000000585 · Cited by 139 · see citing works
“The dopaminergic system showed reduced activity in areas of the brain such as the ventral basal ganglia, while the endogenous opioid system showed a reduction of activity in the rostral and subgenual ACC, orbitofrontal cortex, anterior and posterior insulae, medial thalamus, nucleus accumbens, amygdala, and periacqued…”
ResultDistinct neural representations of placebo and nocebo effects
Freeman, S., Yu, R., Egorova, N., Chen, X., Kirsch, I., Claggett, B., Kaptchuk, T. J., Gollub, R. L., & Kong, J. (2015) · NeuroImage · doi:10.1016/j.neuroimage.2015.03.015 · Cited by 116 · see citing works
“To reinforce these effects, identical moderate intensity stimuli were administered to the neutral squares (Eippert et al., 2009; Kong et al., 2006; Scott et al., 2008; Wagner et al., 2005).”
BackgroundMethodInfluentialLewandowski, K. E., Sperry, S. H., Cohen, B. M., Norris, L. A., Fitzmaurice, G. M., Ongur, D., & Keshavan, M. S. (2017) · The Journal of Clinical Psychiatry · doi:10.4088/jcp.17m11476 · Cited by 115 · see citing works
Placebo 2.0: the impact of expectations on analgesic treatment outcome
Bingel, U. (2020) · Pain · doi:10.1097/j.pain.0000000000001981 · Cited by 113 · see citing works
Does the kappa opioid receptor system contribute to pain aversion?
Cahill, C. M., Taylor, A. M. W., Cook, C., Ong, E., Morón, J. A., & Evans, C. J. (2014) · Frontiers in Pharmacology · doi:10.3389/fphar.2014.00253 · Cited by 105 · see citing works
Neuroendocrinology of Parental Response to Baby‐Cry
Swain, J. E., Kim, P., & Ho, S. S. (2011) · Journal of Neuroendocrinology · doi:10.1111/j.1365-2826.2011.02212.x · Cited by 106 · see citing works
Beyond conformity: Social influences on pain reports and physiology.
Koban, L., & Wager, T. D. (2016) · Emotion · doi:10.1037/emo0000087 · Cited by 92 · see citing works
Mechanisms of the placebo response
Benedetti, F., & Amanzio, M. (2013) · Pulmonary Pharmacology & Therapeutics · doi:10.1016/j.pupt.2013.01.006 · Cited by 93 · see citing works
Bruehl, S., Burns, J. W., Chung, O. Y., & Chont, M. (2009) · Neuroscience & Biobehavioral Reviews · doi:10.1016/j.neubiorev.2008.12.003 · Cited by 88 · see citing works
A Bayesian Perspective on Sensory and Cognitive Integration in Pain Perception and Placebo Analgesia
Anchisi, D., & Zanon, M. (2015) · PLOS ONE · doi:10.1371/journal.pone.0117270 · Cited by 84 · see citing works
Boundary effects of expectation in human pain perception
Hird, E. J., Charalambous, C., El-Deredy, W., Jones, A. K. P., & Talmi, D. (2019) · Scientific Reports · doi:10.1038/s41598-019-45811-x · Cited by 68 · see citing works
Massaly, N., Morón, J. A., & Al-Hasani, R. (2016) · Frontiers in Neuroscience · doi:10.3389/fnins.2016.00480 · Cited by 59 · see citing works
Lee, M. C., Wanigasekera, V., & Tracey, I. (2014) · Neuropharmacology · doi:10.1016/j.neuropharm.2013.06.035 · Cited by 56 · see citing works
Hjorth, O. R., Frick, A., Gingnell, M., Hoppe, J. M., Faria, V., Hultberg, S., Alaie, I., Månsson, K. N. T., Rosén, J., Reis, M., et al. (2021) · Translational Psychiatry · doi:10.1038/s41398-021-01682-3 · Cited by 46 · see citing works
Haloperidol blocks dorsal striatum activity but not analgesia in a placebo paradigm
Wrobel, N., Wiech, K., Forkmann, K., Ritter, C., & Bingel, U. (2014) · Cortex · doi:10.1016/j.cortex.2014.02.023 · Cited by 45 · see citing works
Acute Exercise Influences Reward Processing in Highly Trained and Untrained Men
BOTHE, N., ZSCHUCKE, E., DIMEO, F., HEINZ, A., WÜSTENBERG, T., & STRÖHLE, A. (2013) · Medicine & Science in Sports & Exercise · doi:10.1249/mss.0b013e318275306f · Cited by 37 · see citing works
Nishida, M., Kikuchi, S., Nisijima, K., & Suda, S. (2017) · The Journal of ECT · doi:10.1097/yct.0000000000000352 · Cited by 19 · see citing works
Efecto placebo y contexto terapéutico: un reto en investigación clínica
Morral, A., Urrutia, G., & Bonfill, X. (2017) · Medicina Clínica · doi:10.1016/j.medcli.2017.03.034 · Cited by 19 · see citing works
Placebo effects in children with autism spectrum disorder
Curie, A., Oberlander, T. F., & Jensen, K. B. (2023) · Developmental Medicine & Child Neurology · doi:10.1111/dmcn.15574 · Cited by 16 · see citing works
Furmark, T., Wahlstedt, K., & Faria, V. (2025) · Frontiers in Psychology · doi:10.3389/fpsyg.2025.1531725 · Cited by 1 · see citing works
- Authors
- Scott, D. J., Stohler, C. S., Egnatuk, C. M., Wang, H., Koeppe, R. A., & Zubieta, J.-K.
- Affiliations
- University of Michigan (US)
- University of Maryland, Baltimore (US)
- Venue
- Archives of General Psychiatry
- Publisher
- American Medical Association (AMA)
- Published
- 2008-02-01
- Volume
- 65
- Issue
- 2
- Pages
- 220
- ISSN
- 0003-990X (ISSN-L)
- OpenAlex
- W2013302461
- Cited by
- 637
- References
- 16
- Citations by year
- 2026: 12 · 2025: 18 · 2024: 29 · 2023: 22 · 2022: 24 · 2021: 31 · 2020: 38 · 2019: 39 · 2018: 39 · 2017: 46 · 2016: 41 · 2015: 52 · 2014: 46 · 2013: 43 · 2012: 35
- FWCI
- 20.07
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Archives of General Psychiatry (publishedVersion)
- PubMed (publishedVersion)
- Funders
- National Institute on Drug Abuse (R01DA016423)
- National Center for Complementary and Alternative Medicine
- National Institute of Dental and Craniofacial Research (R01DE015396)
- National Center for Complementary and Integrative Health (R01AT001415)
- Topics
- Life Sciences › Neuroscience › Cognitive Neuroscience › Pain Management and Placebo Effect
- Health Sciences › Medicine › Physiology › Pain Mechanisms and Treatments
- Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neurotransmitter Receptor Influence on Behavior
- Keywords
- placebo effect, nocebo effect, endogenous opioids, dopaminergic system, nucleus accumbens, placebo analgesia, pain anticipation, reward systems, [11C]raclopride, [11C]carfentanil, positron emission tomography
- MeSH terms
- Adult, Analgesics, Brain, Brain Mapping, Carbon Radioisotopes, Culture, Female, Fentanyl, Humans, Image Processing, Computer-Assisted, Male, Synaptic Transmission, Pain, Pain Measurement, Receptors, Dopamine, Receptors, Opioid, Placebo Effect, Receptors, Dopamine D2, Receptors, Opioid, mu, Raclopride, Positron-Emission Tomography, Receptors, Dopamine D3
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
