scholarly journals The Underestimated Significance of Conditioning in Placebo Hypoalgesia and Nocebo Hyperalgesia

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Anne-Kathrin Bräscher ◽  
Michael Witthöft ◽  
Susanne Becker

Placebo and nocebo effects are intriguing phenomena in pain perception with important implications for clinical research and practice because they can alleviate or increase pain. According to current theoretical accounts, these effects can be shaped by verbal suggestions, social observational learning, and classical conditioning and are necessarily mediated by explicit expectation. In this review, we focus on the contribution of conditioning in the induction of placebo hypoalgesia and nocebo hyperalgesia and present accumulating evidence that conditioning independent from explicit expectation can cause these effects. Especially studies using subliminal stimulus presentation and implicit conditioning (i.e., without contingency awareness) that bypass the development of explicit expectation suggest that conditioning without explicit expectation can lead to placebo and nocebo effects in pain perception. Because only few studies have investigated clinical samples, the picture seems less clear when it comes to patient populations with chronic pain. However, conditioning appears to be a promising means to optimize treatment. In order to get a better insight into the mechanisms of placebo and nocebo effects in pain and the possible benefits of conditioning compared to explicit expectation, future studies should carefully distinguish both methods of induction.

2007 ◽  
Author(s):  
Jeffrey I. Gold ◽  
Trina Haselrig ◽  
D. Colette Nicolaou ◽  
Katharine A. Belmont

2019 ◽  
Vol 20 (10) ◽  
pp. 1141-1154 ◽  
Author(s):  
Melanie Beeckman ◽  
Sean Hughes ◽  
Ama Kissi ◽  
Laura E. Simons ◽  
Liesbet Goubert

2021 ◽  
Vol 22 (7) ◽  
pp. 3604
Author(s):  
Nicola Alessio ◽  
Carmela Belardo ◽  
Maria Consiglia Trotta ◽  
Salvatore Paino ◽  
Serena Boccella ◽  
...  

The bioactive form of vitamin .D, 1,25-dihydroxyvitamin D (1,25D3), exerts immunomodulatory actions resulting in neuroprotective effects potentially useful against neurodegenerative and autoimmune diseases. In fact, vitamin D deficiency status has been correlated with painful manifestations associated with different pathological conditions. In this study, we have investigated the effects of vitamin D deficiency on microglia cells, as they represent the main immune cells responsible for early defense at central nervous system (CNS), including chronic pain states. For this purpose, we have employed a model of low vitamin D intake during gestation to evaluate possible changes in primary microglia cells obtained from postnatal day(P)2-3 pups. Afterwards, pain measurement and microglia morphological analysis in the spinal cord level and in brain regions involved in the integration of pain perception were performed in the parents subjected to vitamin D restriction. In cultured microglia, we detected a reactive—activated and proliferative—phenotype associated with intracellular reactive oxygen species (ROS) generation. Oxidative stress was closely correlated with the extent of DNA damage and increased β-galactosidase (B-gal) activity. Interestingly, the incubation with 25D3 or 1,25D3 or palmitoylethanolamide, an endogenous ligand of peroxisome proliferator-activated-receptor-alpha (PPAR-α), reduced most of these effects. Morphological analysis of ex-vivo microglia obtained from vitamin-D-deficient adult mice revealed an increased number of activated microglia in the spinal cord, while in the brain microglia appeared in a dystrophic phenotype. Remarkably, activated (spinal) or dystrophic (brain) microglia were detected in a prominent manner in females. Our data indicate that vitamin D deficiency produces profound modifications in microglia, suggesting a possible role of these cells in the sensorial dysfunctions associated with hypovitaminosis D.


2020 ◽  
Vol 8 (7) ◽  
pp. 1056
Author(s):  
Cody Molnar ◽  
Ekaterina Nikolaeva ◽  
Seonghwan Kim ◽  
Tracey Olson ◽  
Devin Bily ◽  
...  

The increasing movement of exotic pathogens calls for systematic surveillance so that newly introduced pathogens can be recognized and dealt with early. A resource crucial for recognizing such pathogens is knowledge about the spatial and temporal diversity of endemic pathogens. Here, we report an effort to build this resource for Pennsylvania (PA) by characterizing the identity and distribution of Phytophthora species isolated from diverse plant species in PA nurseries and greenhouses. We identified 1137 Phytophthora isolates cultured from clinical samples of >150 plant species submitted to the PA Department of Agriculture for diagnosis from 1975 to 2019 using sequences of one or more loci and morphological characteristics. The three most commonly received plants were Abies, Rhododendron, and Pseudotsuga. Thirty-six Phytophthora species identified represent all clades, except 3 and 10, and included a distinct subgroup of a known species and a prospective new species. Prominent pathogenic species such as P. cactorum, P. cinnamomi, P. nicotianae, P. drechsleri, P. pini, P. plurivora, and P. sp. kelmania have been found consistently since 1975. One isolate cultured from Juniperus horizontalis roots did not correspond to any known species, and several other isolates also show considerable genetic variation from any authentic species or isolate. Some species were isolated from never-before-documented plants, suggesting that their host range is larger than previously thought. This survey only provides a coarse picture of historical patterns of Phytophthora encounters in PA nurseries and greenhouses because the isolation of Phytophthora was not designed for a systematic survey. However, its extensive temporal and plant coverage offers a unique insight into the association of Phytophthora with diverse plants in nurseries and greenhouses.


2021 ◽  
pp. 004912412098618
Author(s):  
Tim de Leeuw ◽  
Steffen Keijl

Although multiple organizational-level databases are frequently combined into one data set, there is no overview of the matching methods (MMs) that are utilized because the vast majority of studies does not report how this was done. Furthermore, it is unclear what the differences are between the utilized methods, and it is unclear whether research findings might be influenced by the utilized method. This article describes four commonly used methods for matching databases and potential issues. An empirical comparison of those methods used to combine regularly used organizational-level databases reveals large differences in the number of observations obtained. Furthermore, empirical analyses of these different methods reveal that several of them produce both systematic and random errors. These errors can result in erroneous estimations of regression coefficients in terms of direction and/or size as well as an issue where truly significant relationships might be found to be insignificant. This shows that research findings can be influenced by the MM used, which would argue in favor of the establishment of a preferred method as well as more transparency on the utilized method in future studies. This article provides insight into the matching process and methods, suggests a preferred method, and should aid researchers, reviewers, and editors with both combining multiple databases and describing and assessing them.


2021 ◽  
Author(s):  
Esther Benedetti ◽  
James Burnett ◽  
Meredith Degnan ◽  
Danielle Horne ◽  
Andres Missair ◽  
...  

The neuronal, chemical, and electrical transmission of pain is a complex and intricate subject that continues to be studied and expounded. This review discusses the relevant physiology and influential factors contributing to the experience and subjective variation in a variety of acute and chronic pain presentations. This review contains 4 figures, 4 tables, and 30 references Keywords: acute pain, chronic pain, somatic pain, neuropathic pain, visceral pain, nociception, pain perception, gender-related pain, cancer pain, spine pain


Geriatrics ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 64
Author(s):  
Fang Liu ◽  
Min Tong

Background and objective: Worldwide, 26 million older adults die from chronic disease, and chronic pain is typically a part of the experience of chronic disease. This study explores the perception of chronic pain for home-dwelling Chinese older adults and its influence on (1) self-management ability and (2) management and reduction of chronic pain. Methods: Adopting a qualitative study design, we conducted in-depth interviews with 10 Chinese community-dwelling older adults who experience chronic pain. Half of our informants perceive chronic pain, whereas the other half, diagnosed with Alzheimer’s disease, do not report that they perceive chronic pain. Data were analyzed with inductive thematic analysis. Results: Chronic pain perception plays important roles in (1) defining the challenge of self-management, (2) connecting previous caretaking experience, (3) adjusting the identity of self-management, (4) acquiring support from important others and (5) re-planning self-management arrangements. Conclusion: Pain perception helps to motivate Chinese older adults to face health challenges and regain self-management capacity through adjustments in self-identity and care experience with the support of important others. Pain perception can consolidate the situation of independent living of older adults. It helps to motivate Chinese older adults to face health challenges and regain self-management capacity.


2019 ◽  
Author(s):  
Yuru Song ◽  
Mingchen Yao ◽  
Helen Kemprecos ◽  
Áine Byrne ◽  
Zhengdong Xiao ◽  
...  

AbstractPain is a complex, multidimensional experience that involves dynamic interactions between sensory-discriminative and affective-emotional processes. Pain experiences have a high degree of variability depending on their context and prior anticipation. Viewing pain perception as a perceptual inference problem, we use a predictive coding paradigm to characterize both evoked and spontaneous pain. We record the local field potentials (LFPs) from the primary somatosensory cortex (S1) and the anterior cingulate cortex (ACC) of freely behaving rats—two regions known to encode the sensory-discriminative and affective-emotional aspects of pain, respectively. We further propose a framework of predictive coding to investigate the temporal coordination of oscillatory activity between the S1 and ACC. Specifically, we develop a high-level, empirical and phenomenological model to describe the macroscopic dynamics of bottom-up and top-down activity. Supported by recent experimental data, we also develop a mechanistic mean-field model to describe the mesoscopic population neuronal dynamics in the S1 and ACC populations, in both naive and chronic pain-treated animals. Our proposed predictive coding models not only replicate important experimental findings, but also provide new mechanistic insight into the uncertainty of expectation, placebo or nocebo effect, and chronic pain.Author SummaryPain perception in the mammalian brain is encoded through multiple brain circuits. The experience of pain is often associated with brain rhythms or neuronal oscillations at different frequencies. Understanding the temporal coordination of neural oscillatory activity from different brain regions is important for dissecting pain circuit mechanisms and revealing differences between distinct pain conditions. Predictive coding is a general computational framework to understand perceptual inference by integrating bottom-up sensory information and top-down expectation. Supported by experimental data, we propose a predictive coding framework for pain perception, and develop empirical and biologically-constrained computational models to characterize oscillatory dynamics of neuronal populations from two cortical circuits—one for the sensory-discriminative experience and the other for affective-emotional experience, and further characterize their temporal coordination under various pain conditions. Our computational study of biologically-constrained neuronal population model reveals important mechanistic insight on pain perception, placebo analgesia, and chronic pain.


Pain Medicine ◽  
2016 ◽  
pp. pnw186
Author(s):  
Dmitry Y. Yakunchikov ◽  
Camille J. Olechowski ◽  
Mark K. Simmonds ◽  
Michelle J. Verrier ◽  
Saifudin Rashiq ◽  
...  

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