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Neural Plasticity 2020Most of the occupational exposure limits (OELs) are based on local irritants. However, exposure to much lower concentrations of irritant substances can also lead to...
Most of the occupational exposure limits (OELs) are based on local irritants. However, exposure to much lower concentrations of irritant substances can also lead to health complaints from workers. Exposure to irritants is often accompanied by strong unpleasant odors, and strong odors might have distracting effects and hence pose a safety risk. The findings obtained in human exposure studies with chemically sensitive, stressed, or anxious persons suggest that their ability to direct attention away from the odorous exposure and to focus on a cognitive task is reduced. In addition, after repeated odor exposure, these persons show signs of sensitization, i.e., difficulties in ignoring or getting used to the exposure. The question arises as to whether certain health conditions are accompanied by a change in sensitivity to odors and irritants, so that these persons are potentially more distracted by odors and irritants and therefore more challenged in working memory tasks than nonsusceptible persons. In our study, susceptible persons with sensory airway hyperreactivity ("capsaicin-sensitive") respond more strongly to mechanical skin stimuli than controls and show altered network connectivity. Capsaicin-sensitive subjects have a lower pain threshold and thus are more sensitive to mechanical skin stimuli. The intrinsic functional connectivity of their saliency network is higher, and the lower the GABAergic tone of the thalamus, the higher their pain sensitivity to mechanical stimuli. It seems that the increased communication between resting-state networks promotes a stronger perception of the sensory input signal. The results can be used to inform about actual risks (i.e., attention diversion and increased risk of accidents) and "pseudo" risks such as odor perception without a negative impact on one's well-being. This way, uncertainties that still prevail in the health assessment of odorous and sensory irritating chemicals could be reduced.
Topics: Adult; Brain; Capsaicin; Female; Glutamic Acid; Humans; Male; Neural Pathways; Nociception; Pain Perception; Young Adult; gamma-Aminobutyric Acid
PubMed: 33178262
DOI: 10.1155/2020/9125913 -
Best Practice & Research. Clinical... Dec 2017The difficulty of defining the three so-called components of « an-esthesia » is emphasized: hypnosis, absence of movement, and adequacy of anti-nociception... (Review)
Review
The difficulty of defining the three so-called components of « an-esthesia » is emphasized: hypnosis, absence of movement, and adequacy of anti-nociception (intraoperative « analgesia »). Data obtained from anesthetized animals or humans delineate the activation of cardiac and vasomotor sympathetic reflex (somato-sympathetic reflex) and the cardiac parasympathetic deactivation observed following somatic stimuli. Sympathetic activation and parasympathetic deactivation are used as monitors to address the adequacy of intraoperative anti-nociception. Finally, intraoperative nociception through the administration of nonopioid analgesics vs. opioid analgesics is considered to achieve minimal postoperative side effects.
Topics: Analgesics; Anesthesia; Animals; Humans; Intraoperative Neurophysiological Monitoring; Neural Pathways; Pain Measurement; Pain Perception; Regional Blood Flow
PubMed: 29739535
DOI: 10.1016/j.bpa.2017.05.001 -
The Laryngoscope Dec 2012
Review
Topics: Adaptation, Psychological; Humans; Pain Perception; Sleep; Sleep Deprivation
PubMed: 23239140
DOI: 10.1002/lary.23488 -
NeuroImage Jan 2017Decoding the neural representations of pain is essential to obtaining an objective assessment as well as an understanding of its underlying mechanisms. The complexities...
Decoding the neural representations of pain is essential to obtaining an objective assessment as well as an understanding of its underlying mechanisms. The complexities involved in the subjective experience of pain make it difficult to obtain a quantitative assessment from the induced spatiotemporal patterns of brain activity of high dimensionality. Most previous studies have investigated the perception of pain by analyzing the amplitude or spatial patterns in the response of the brain to external stimulation. This study investigated the decoding of endogenous pain perceptions according to resting-state magnetoencephalographic (MEG) recordings. In our experiments, we applied a beamforming method to calculate the brain activity for every brain region and examined temporal and spectral features of brain activity for predicting the intensity of perceived pain in patients with primary dysmenorrhea undergoing menstrual pain. Our results show that the asymmetric index of sample entropy in the precuneus and the sample entropy in the left posterior cingulate gyrus were the most informative characteristics associated with the perception of menstrual pain. The correlation coefficient (ρ=0.64, p<0.001) between the predicted and self-reported pain scores demonstrated the high prediction accuracy. In addition to the estimated brain activity, we were able to predict accurate pain scores directly from MEG channel signals (ρ=0.65, p<0.001). These findings suggest the possibility of using the proposed model based on resting-state MEG to predict the perceived intensity of endogenous pain.
Topics: Adult; Brain; Dysmenorrhea; Entropy; Female; Functional Laterality; Humans; Magnetoencephalography; Pain Perception; Signal Processing, Computer-Assisted; Young Adult
PubMed: 27746387
DOI: 10.1016/j.neuroimage.2016.09.040 -
Journal of Health Psychology Feb 2021Inequity and pain typically co-appear during disasters or illnesses and have significant effects on health. However, the relationship between inequity and pain...
Inequity and pain typically co-appear during disasters or illnesses and have significant effects on health. However, the relationship between inequity and pain perception is poorly understood. Four studies investigated whether perceived inequity modulates pain perception using different priming paradigms and pain measurements. Studies 1-3 consistently revealed that participants perceived pain more intensely and rapidly after inequity priming. Study 4 demonstrated that inequity in cancer patients predicts pain perception after controlling for individual differences in equity sensitivity and pain sensitivity. The findings suggest that equity may help manage adversity in achieving mental and physical health.
Topics: Humans; Pain; Pain Perception
PubMed: 30295088
DOI: 10.1177/1359105318802936 -
Best Practice & Research. Clinical... Dec 2017Pain in spondyloarthritis is usually attributed to inflammation. However, treatment with potent biologic agents that control inflammation does not always control the... (Review)
Review
Pain in spondyloarthritis is usually attributed to inflammation. However, treatment with potent biologic agents that control inflammation does not always control the pain. Pain is hence likely to be multifactorial. Fatigue is another prominent feature of this condition which again tends to respond poorly to potent biologic agents. There is also a growing interest in coexisting fibromyalgia in this group of patients and how this affects response to biologic therapies. Advances in neuroimaging have helped in better understanding the dynamic nature of brain networks in the perception of pain. Animal models have helped in developing concepts of peripheral and central sensitization in pain transmission. This review discusses the neuroimmune basis of pain in ankylosing spondylitis, with an emphasis on brain networks and the complex interactions between the nervous system and the immune system at various levels. It also provides some insights into the differences in pain perception between men and women.
Topics: Animals; Central Nervous System Sensitization; Female; Humans; Male; Neuroimmunomodulation; Pain; Pain Perception; Spondylarthritis
PubMed: 30509443
DOI: 10.1016/j.berh.2018.07.003 -
Trends in Neurosciences Apr 2016How perception of pain emerges from neural activity is largely unknown. Identifying a neural 'pain signature' and deriving a way to predict perceived pain from brain... (Review)
Review
How perception of pain emerges from neural activity is largely unknown. Identifying a neural 'pain signature' and deriving a way to predict perceived pain from brain activity would have enormous basic and clinical implications. Researchers are increasingly turning to functional brain imaging, often applying machine-learning algorithms to infer that pain perception occurred. Yet, such sophisticated analyses are fraught with interpretive difficulties. Here, we highlight some common and troublesome problems in the literature, and suggest methods to ensure researchers draw accurate conclusions from their results. Since functional brain imaging is increasingly finding practical applications with real-world consequences, it is critical to interpret brain scans accurately, because decisions based on neural data will only be as good as the science behind them.
Topics: Animals; Brain; Brain Mapping; Humans; Pain Perception
PubMed: 26898163
DOI: 10.1016/j.tins.2016.01.004 -
Rinsho Shinkeigaku = Clinical Neurology Nov 2010Both electrophysiological studies such as magnetoencephalography (MEG) and hemodynamic studies such as functional magnetic resonance imaging (fMRI) are intensively being... (Review)
Review
Both electrophysiological studies such as magnetoencephalography (MEG) and hemodynamic studies such as functional magnetic resonance imaging (fMRI) are intensively being used to elucidate underlying mechanisms of human pain and itch perception. MEG following A-delta (first pain) and C fiber stimulation (second pain) were similar except for a longer latency for the latter. At first, primary somatosensory cortex (SI) contralateral to the stimulation is activated and then secondary somatosensory cortex (SII), insula, amygdala and anterior cingulate cortex (ACC) in the bilateral hemispheres are activated sequentially. As for findings using fMRI, the stimulation of both C and A-delta fibers activated the bilateral thalamus, bilateral SII, right (ipsilateral) middle insula, and bilateral Brodmann's area (BA) 24/32, with the majority of activity found in the posterior portion of the ACC. However, magnitude of activity in the BA32/8/6, including ACC and pre-supplementary motor area (pre-SMA), and the bilateral anterior insula was significantly stronger following the stimulation of C nociceptors than A-delta nociceptors. Findings following itch stimulation were similar to those following pain stimulation, but the precuneus may be itch selective brain region. This unique finding was confirmed by both MEG and fMRI studies.
Topics: Humans; Limbic System; Magnetic Resonance Imaging; Magnetoencephalography; Pain Perception; Pruritus
PubMed: 21921542
DOI: 10.5692/clinicalneurol.50.997 -
Trends in Cognitive Sciences Jul 2023Why is analgesic treatment more effective when it is self-administered? Strube et al. compare two possible accounts and show that the effect of agency on perception is...
Why is analgesic treatment more effective when it is self-administered? Strube et al. compare two possible accounts and show that the effect of agency on perception is linked to a shift in expectation (prior) rather than to reduced likelihood precision, highlighting that agency has a profound impact on the entire perceptual process.
Topics: Humans; Pain Perception; Probability
PubMed: 37198090
DOI: 10.1016/j.tics.2023.04.011 -
PLoS Computational Biology Jan 2017Perception is seen as a process that utilises partial and noisy information to construct a coherent understanding of the world. Here we argue that the experience of pain... (Review)
Review
Perception is seen as a process that utilises partial and noisy information to construct a coherent understanding of the world. Here we argue that the experience of pain is no different; it is based on incomplete, multimodal information, which is used to estimate potential bodily threat. We outline a Bayesian inference model, incorporating the key components of cue combination, causal inference, and temporal integration, which highlights the statistical problems in everyday perception. It is from this platform that we are able to review the pain literature, providing evidence from experimental, acute, and persistent phenomena to demonstrate the advantages of adopting a statistical account in pain. Our probabilistic conceptualisation suggests a principles-based view of pain, explaining a broad range of experimental and clinical findings and making testable predictions.
Topics: Bayes Theorem; Humans; Models, Neurological; Models, Statistical; Pain; Pain Perception
PubMed: 28081134
DOI: 10.1371/journal.pcbi.1005142