Peripheral neural mechanisms of cutaneous heat hyperalgesia and heat pain

2018 ◽  
Author(s):  
Amanda H. Klein ◽  
Matthias Ringkamp
Keyword(s):  
Experimental Approach ◽  
Burn Injury ◽  
Neural Mechanisms ◽  
Heat Pain ◽  
Nerve Fibres ◽  
Thermal Test ◽  
Human Volunteers ◽  
Electrophysiological Studies ◽  
Conditioning Stimuli ◽  
Heat Hyperalgesia

In the landmark paper discussed in this chapter, published in 1982, LaMotte et al. investigated the contribution of different cutaneous nerve fibres to heat pain and heat hyperalgesia in both psychophysical (humans) and electrophysiological studies (human and primates), using identical thermal test and conditioning stimuli; the findings from the two sets of experiments were then correlated. In non-human primates, neuronal activity was recorded from mechanoheat-sensitive A- and C-fibres (AMHs and CMHs, respectively) and warm and cold fibres, whereas, in conscious human volunteers, activity from CMHs was recorded. The authors found that pain is mediated by activity in CMHs and that sensitization of CMHs after a mild burn injury accounts for the increased heat pain after such injury. The combination of psychophysical experiments in human and correlative electrophysiological studies in non-human primates provides an important experimental approach for unravelling the contribution of different classes of afferents to pain.

scholarly journals Sodium Channel Nav1.7 Is Essential for Lowering Heat Pain Threshold after Burn Injury

2012 ◽  
Vol 32 (32) ◽  
pp. 10819-10832 ◽  
Author(s):  
S. D. Shields ◽  
X. Cheng ◽  
N. Uceyler ◽  
C. Sommer ◽  
S. D. Dib-Hajj ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Pain Threshold ◽  
Burn Injury ◽  
Heat Pain ◽  
Heat Pain Threshold

scholarly journals Midfrontal neural dynamics distinguish between general control and inhibition-specific processes in the stopping of motor actions

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jakob Kaiser ◽  
Natalie Annette Simon ◽  
Paul Sauseng ◽  
Simone Schütz-Bosbach
Keyword(s):  
Error Rates ◽  
Neural Mechanisms ◽  
Oscillatory Activity ◽  
General Control ◽  
Selective Marker ◽  
Human Volunteers ◽  
Action Change ◽  
Motor Actions ◽  
Action Inhibition ◽  
Theta Range

Abstract Action inhibition, the suppression of action impulses, is crucial for goal-directed behaviour. In order to dissociate neural mechanisms specific to motor stopping from general control processes which are also relevant for other types of conflict adjustments, we compared midfrontal oscillatory activity in human volunteers via EEG between action inhibition and two other types of motor conflicts, unexpected action activation and unexpected action change. Error rates indicated that action activation was significantly easier than the other two equally demanding tasks. Midfrontal brain oscillations were significantly stronger for inhibition than for both other conflict types. This was driven by increases in the delta range (2–3 Hz), which were higher for inhibition than activation and action change. Increases in the theta range (4–7 Hz) were equally high for inhibition and change, but lower for action activation. These findings suggest that inhibition is facilitated by neural mechanisms specific to motor-stopping, with midfrontal delta being a potentially selective marker of motor inhibition.

scholarly journals Assessment of Drug Delivery Kinetics to Epidermal Targets In Vivo

2021 ◽  
Vol 23 (3) ◽  
Author(s):  
M. Hoppel ◽  
M. A. M. Tabosa ◽  
A. L. Bunge ◽  
M. B. Delgado-Charro ◽  
R. H. Guy
Keyword(s):  
Experimental Approach ◽  
Input Function ◽  
Drug Uptake ◽  
Tape Stripping ◽  
Healthy Human ◽  
Topical Product ◽  
Human Volunteers ◽  
Dermal Pharmacokinetics

AbstractIt has proven challenging to quantify ‘drug input’ from a formulation to the viable skin because the epidermal and dermal targets of topically applied drugs are difficult, if not impossible, to access in vivo. Defining the drug input function to the viable skin with a straightforward and practical experimental approach would enable a key component of dermal pharmacokinetics to be characterised. It has been hypothesised that measuring drug uptake into and clearance from the stratum corneum (SC) by tape-stripping allows estimation of a topical drug’s input function into the viable tissue. This study aimed to test this idea by determining the input of nicotine and lidocaine into the viable skin, following the application of commercialised transdermal patches to healthy human volunteers. The known input rates of these delivery systems were used to validate and assess the results from the tape-stripping protocol. The drug input rates from in vivo tape-stripping agreed well with the claimed delivery rates of the patches. The experimental approach was then used to determine the input of lidocaine from a marketed cream, a typical topical product for which the amount of drug absorbed has not been well-characterised. A significantly higher delivery of lidocaine from the cream than from the patch was found. The different input rates between drugs and formulations in vivo were confirmed qualitatively and quantitatively in vitro in conventional diffusion cells using dermatomed abdominal pig skin.

Increased contact heat pain and shortened latencies of contact heat evoked potentials following capsaicin-induced heat hyperalgesia

2012 ◽  
Vol 123 (7) ◽  
pp. 1429-1436 ◽  
Author(s):  
C.S. Madsen ◽  
B. Johnsen ◽  
A. Fuglsang-Frederiksen ◽  
T.S. Jensen ◽  
N.B. Finnerup
Keyword(s):  
Evoked Potentials ◽  
Heat Pain ◽  
Contact Heat ◽  
Contact Heat Evoked Potentials ◽  
Heat Hyperalgesia

scholarly journals Effect of Cutaneous Heat Pain on Corticospinal Excitability of the Tibialis Anterior at Rest and during Submaximal Contraction

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Maxime Billot ◽  
Cécilia Neige ◽  
Martin Gagné ◽  
Catherine Mercier ◽  
Laurent J. Bouyer
Keyword(s):  
Motor Control ◽  
Tibialis Anterior ◽  
Motor Evoked Potentials ◽  
Corticospinal Excitability ◽  
Neural Mechanisms ◽  
Heat Pain ◽  
Thermal Pain ◽  
Submaximal Contraction ◽  
Main Effect ◽  
Pain Ratings

Previous studies have shown that pain can interfere with motor control. The neural mechanisms underlying these effects remain largely unknown. At the upper limb, mounting evidence suggests that pain-induced reduction in corticospinal excitability is involved. No equivalent data is currently available at the lower limb. The present study therefore examined the effect of thermal pain on the corticospinal drive to tibialis anterior (TA) at rest and during an isometric submaximal dorsiflexion. Transcranial magnetic stimulation was used to induce motor-evoked potentials (MEPs) in the TA at rest and during contraction in the presence or absence of cutaneous heat pain induced by a thermode positioned above the TA (51°C during 1 s). With similar pain ratings between conditions (3.9/10 at rest and 3.6/10 during contraction), results indicate significant decreases in MEP amplitude during both rest (−9%) and active conditions (−13%) (main effect of pain, p=0.02). These results therefore suggest that cutaneous heat pain can reduce corticospinal excitability in the TA muscle and that such reduction in corticospinal excitability could contribute to the interference of pain on motor control/motor learning.

scholarly journals Distinct neural mechanisms for spatially lateralized and spatially global visual working memory representations

2016 ◽  
Vol 116 (4) ◽  
pp. 1715-1727 ◽  
Author(s):  
Keisuke Fukuda ◽  
Min-Suk Kang ◽  
Geoffrey F. Woodman
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Visual Working Memory ◽  
Imaging Techniques ◽  
Event Related Potentials ◽  
Neural Mechanisms ◽  
Electrophysiological Studies ◽  
Related Potentials ◽  
Memory Representations ◽  
Α Band

Visual working memory (VWM) allows humans to actively maintain a limited amount of information. Whereas previous electrophysiological studies have found that lateralized event-related potentials (ERPs) track the maintenance of information in VWM, recent imaging experiments have shown that spatially global representations can be read out using the activity across the visual cortex. The goal of the present study was to determine whether both lateralized and spatially global electrophysiological signatures coexist. We first show that it is possible to simultaneously measure lateralized ERPs that track the number of items held in VWM from one visual hemfield and parietooccipital α (8–12 Hz) power over both hemispheres indexing spatially global VWM representations. Next, we replicated our findings and went on to show that this bilateral parietooccipital α power as well as the contralaterally biased ERP correlate of VWM carries a signal that can be used to decode the identity of the representations stored in VWM. Our findings not only unify observations across electrophysiology and imaging techniques but also suggest that ERPs and α-band oscillations index different neural mechanisms that map on to lateralized and spatially global representations, respectively.

scholarly journals Thermal Pain in Complex Regional Pain Syndrome Type I

2014 ◽  
Vol 17;1 (1;17) ◽  
pp. 71-79
Author(s):  
John R. Grothusen
Keyword(s):  
Complex Regional Pain Syndrome ◽  
Quantitative Sensory Testing ◽  
Thermal Hyperalgesia ◽  
Pain Syndrome ◽  
Heat Pain ◽  
Syndrome Type ◽  
Sensory Testing ◽  
Cold Pain ◽  
Thermal Pain ◽  
Heat Hyperalgesia

Background: Quantitative sensory testing (QST), with thermal threshold determinations, is a routine part of the comprehensive clinical workup of patients suffering from chronic pain, especially those with Complex Regional Pain Syndrome seen at our outpatient pain clinic. This is done to quantitatively assess each patient’s small fiber and sensory function in a controlled manner. Most patients have normal sensory detection thresholds, but there are large differences in thermal pain thresholds. Some patients display no thermal hyperalgesia, while other patients display severe thermal hyperalgesia when tested in all 4 limbs. Objectives: To ascertain the prevalence of thermal hyperalgesia in patients with complex regional pain syndrome type 1 (CRPS-I). Study Design: This was a retrospective review of the results of QST performed on 105 patients as part of their clinical workup. Setting: The outpatient clinic of the Department of Neurology at Drexel University College of Medicine. Methods: All patients had a diagnosis of CRPS-I. Thermal quantitative sensory testing, including cool detection, warm detection, cold pain, and heat pain, was performed on 8 distal sites on each patient as part of a comprehensive clinical examination. Results: With regards to thermal hyperalgesia, patients with CPRS-I appear to fall into distinct groups. One subgroup displays evidence of generalized cold and heat hyperalgesia, one subgroup displays evidence of generalized cold hyperalgesia only, one displays evidence of heat hyperalgesia only, and one subgroup does not display evidence of cold or heat hyperalgesia. Limitations: This study is based on retrospective information on a relatively small (105 patient records) number of patients. Since only patients with CRPS-I were included, the results are only applicable to this group. Conclusions: Thermal QST provides useful information about the sensory phenotype of individual patients. Subgrouping based on thermal hyperalgesia may be useful for future studies regarding prognosis, treatment selection, and efficacy. Key words: Complex regional pain syndrome, CRPS, quantitative sensory testing, QST, cold pain, heat pain, thermal hyperalgesia

scholarly journals Impact of Dietary Lipids on Colonic Function and Microbiota: An Experimental Approach Involving Orlistat-Induced Fat Malabsorption in Human Volunteers

2016 ◽  
Vol 7 (4) ◽  
pp. e161 ◽  
Author(s):  
Pamela Morales ◽  
Sayaka Fujio ◽  
Paola Navarrete ◽  
Juan A Ugalde ◽  
Fabien Magne ◽  
...  
Keyword(s):  
Experimental Approach ◽  
Dietary Lipids ◽  
Human Volunteers ◽  
Fat Malabsorption
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