1
|
Rujoie A, Andersen OK, Frahm KS. Investigation of directional discrimination in the nociceptive system using temperature-controlled laser stimuli. Eur J Pain 2024. [PMID: 38440936 DOI: 10.1002/ejp.2259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 01/30/2024] [Accepted: 02/26/2024] [Indexed: 03/06/2024]
Abstract
BACKGROUND Cutaneous laser stimulation has commonly been employed to investigate the thermal properties of the nociceptive system. The aim of this study was to investigate how a temperature-controlled laser system improves the assessment of directional discrimination in the nociceptive system. METHODS In total, twenty healthy volunteers participated in this study. To determine the directional discrimination threshold (stimulation length 50% correct, expressed in mm), thermal stimuli were delivered using a diode laser and the laser beam was perpendicularly displaced across the skin to give a linear stimulation in four different directions (distal, proximal, lateral and medial) and displacement lengths (3 for lateral-medial and 5 for distal-proximal). Two temperature control modes were used in the stimulation system, open-loop and closed-loop control. The subjects had to report the perceived stimulus direction, the degree of certainty regarding the perceived direction and the intensity of the perceived stimulus (0-10 numerical rating scale, 3: pain threshold). RESULTS During closed-loop control, the orientation of stimuli was discriminated significantly more accurately than during open-loop control. During closed-loop control, the directional discrimination threshold was 31.9 and 26.1 mm for distal-proximal and lateral-medial directed stimuli, respectively. A numerical rating scale was significantly higher for the lateral/medial directions. Moreover, the variability of the discrimination threshold is reduced in the closed-loop control system. CONCLUSIONS The findings show that discrimination ability is better in the lateral-medial directions compared to the distal-proximal directions. This study indicates that using a system enabling closed-loop temperature control, allows more robust probing of the temporo-spatial mechanisms in the nociceptive system. SIGNIFICANCE This study shows that a newly developed temperature-controlled laser stimulation system enhances the possibilities to investigate the nociceptive temporo-spatial integration, as shown by a less variable directional discrimination threshold. The results also show that different orthogonal directions are discriminated differently. This new method allows a better investigation of the combined temporal and spatial mechanisms in the nociceptive system.
Collapse
Affiliation(s)
- Ahmad Rujoie
- Integrative Neuroscience Group, Center for Neuroplasticity and Pain (CNAP), Department of Health Science & Technology, Aalborg University, Aalborg, Denmark
| | - Ole Kaeseler Andersen
- Integrative Neuroscience Group, Center for Neuroplasticity and Pain (CNAP), Department of Health Science & Technology, Aalborg University, Aalborg, Denmark
| | - Ken Steffen Frahm
- Integrative Neuroscience Group, Center for Neuroplasticity and Pain (CNAP), Department of Health Science & Technology, Aalborg University, Aalborg, Denmark
| |
Collapse
|
2
|
Borbjerg MK, Antonsson E, Røikjer J, Ejskjaer N, Mørch CD. The stability of perception threshold tracking for long session evaluation of Aβ- and Aδ-fiber function. Muscle Nerve 2023; 68:743-749. [PMID: 37676114 DOI: 10.1002/mus.27967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 08/15/2023] [Accepted: 08/20/2023] [Indexed: 09/08/2023]
Abstract
INTRODUCTION/AIMS Research has proven that epidermal and transcutaneous stimulation can identify the function of Aβ and Aδ fibers (i.e., in diabetes) individually using different electrodes. In this study we aimed to determine the stability of perception thresholds when using such electrodes. METHODS Twenty healthy volunteers participated in this study. The perception threshold of Aβ fibers (patch electrode) and Aδ fibers (pin electrode) was estimated 30 times during a period of 60 minutes. A threshold was established every other minute, alternating between the two electrodes. The stimulus duration was 1 millisecond and the interstimulus interval was 1.5 to 2.5 seconds. Linear regressions of the perception threshold as a function of time were performed. The slopes were used as an estimate of habituation and were compared between the electrodes. RESULTS The slope was significantly larger when assessed by the pin electrode (median: 0.020 [0.009 to 0.030] mA/trial) than when assessed by the patch electrode (median: 0.005 [0.001 to 0.018] mA/trial) (P = .017, paired t test). During the session, total increases in perception threshold of approximately 55% and 1% were seen for the pin and patch electrodes, respectively. DISCUSSION The two fiber types assessed showed significant perception threshold increases. The higher slope of the pin electrode indicated that the Aδ fibers were more prone to habituation than the Aβ fibers, and that habituation should be considered during prolonged experiments. This assessment is valuable for future research on nerve fiber function using the technique for long session experiments.
Collapse
Affiliation(s)
- Mette Krabsmark Borbjerg
- Faculty of Medicine, University of Aalborg, Aalborg, Denmark
- Steno Diabetes Center North Denmark, Aalborg University Hospital, Aalborg, Denmark
| | - Elin Antonsson
- Faculty of Medicine, University of Aalborg, Aalborg, Denmark
| | - Johan Røikjer
- Steno Diabetes Center North Denmark, Aalborg University Hospital, Aalborg, Denmark
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Niels Ejskjaer
- Steno Diabetes Center North Denmark, Aalborg University Hospital, Aalborg, Denmark
- Departments of Endocrinology and Clinical Medicine, Aalborg University Hospital, Aalborg, Denmark
| | - Carsten Dahl Mørch
- Center for Neuroplasticity and Pain, SMI, Department of Health Science and Technology, School of Medicine, Aalborg University, Aalborg, Denmark
| |
Collapse
|
3
|
Adamczyk WM, Katra M, Szikszay TM, Peugh J, King CD, Luedtke K, Coghill RC. Spatial Tuning in Nociceptive Processing Is Driven by Attention. THE JOURNAL OF PAIN 2023; 24:1116-1125. [PMID: 36965648 PMCID: PMC10330125 DOI: 10.1016/j.jpain.2023.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 03/07/2023] [Accepted: 03/13/2023] [Indexed: 03/27/2023]
Abstract
When the source of nociception expands across a body area, the experience of pain increases due to the spatial integration of nociceptive information. This well-established effect is called spatial summation of pain (SSp) and has been the subject of multiple investigations. Here, we used cold-induced SSp to investigate the effect of attention on the spatial tuning of nociceptive processing. Forty pain-free volunteers (N = 40, 20 females) participated in this experiment. They took part in an SSp paradigm based on three hand immersions into cold water (5°C): Participants either immersed the radial segment ("a"), ulnar segment ("b") or both hand segments ("a+b") and provided overall pain ratings. In some trials based on "a+b" immersions, they were also asked to provide divided (ie, first pain in "a" then in "b"; or reversed) and directed attention ratings (ie, pain only in "a" or "b"). Results confirmed a clear SSp effect in which reported pain during immersions of "a" or "b" was less intense than pain during immersions of "a+b" (P < .001). Data also confirmed that spatial tuning was altered. SSp was abolished when participants provided two ratings in a divided fashion (P < .001). Furthermore, pain was significantly lower when attention was directed only to one segment ("a" OR "b") during "a+b" immersion (P < .001). We conclude that spatial tuning is dynamically driven by attention as reflected in abolished SSp. Directed attention was sufficient to focus spatial tuning and abolish SSp. Results support the role of cognitive processes such as attention in spatial tuning. PERSPECTIVE: This article presents experimental investigation of spatial tuning in pain and offers mechanistic insights of contiguous spatial summation of pain in healthy volunteers. Depending on how pain is evaluated in terms of attentional derivative (overall pain, directed, divided attention) the pain is reduced and spatial summation abolished.
Collapse
Affiliation(s)
- Waclaw M Adamczyk
- Pediatric Pain Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati School of Medicine, Cincinnati, Ohio; Laboratory of Pain Research, Institute of Physiotherapy and Health Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland.
| | - Michal Katra
- Laboratory of Pain Research, Institute of Physiotherapy and Health Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Tibor M Szikszay
- Department of Physiotherapy, Pain and Exercise Research Lübeck (P.E.R.L.), Institute of Health Sciences, Universität zu Lübeck, Lübeck, Germany
| | - James Peugh
- Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati School of Medicine, Cincinnati, Ohio
| | - Christopher D King
- Pediatric Pain Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati School of Medicine, Cincinnati, Ohio
| | - Kerstin Luedtke
- Laboratory of Pain Research, Institute of Physiotherapy and Health Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland; Department of Physiotherapy, Pain and Exercise Research Lübeck (P.E.R.L.), Institute of Health Sciences, Universität zu Lübeck, Lübeck, Germany
| | - Robert C Coghill
- Pediatric Pain Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati School of Medicine, Cincinnati, Ohio
| |
Collapse
|
4
|
Nonlinear increase of pain in distance-based and area-based spatial summation. Pain 2021; 162:1771-1780. [PMID: 33449502 DOI: 10.1097/j.pain.0000000000002186] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 12/30/2020] [Indexed: 11/25/2022]
Abstract
ABSTRACT When nociceptive stimulation affects a larger body area, pain increases. This effect is called spatial summation of pain (SSp). The aim of this study was to describe SSp as a function of the size or distance of a stimulated area(s) and to test how this function is shaped by the intensity and SSp test paradigm. Thirty-one healthy volunteers participated in a within-subject experiment. Participants were exposed to area-based and distanced-based SSp. For area-based SSp, electrocutaneous noxious stimuli were applied by up to 5 electrodes (5 areas) forming a line-like pattern; for distance-based SSp, the same position and lengths of stimuli were used but only 2 electrodes were stimulated. Each paradigm was repeated using pain of low, moderate, and high intensity. It was found that the pattern of pain intensity followed a logarithmic (power) rather than a linear function. The dynamics of the pain increase were significantly different across pain intensities, with more summation occurring when pain was perceived as low. Results indicated that area-based SSp is more painful than distance-based SSp when low and moderate but not when high pain intensity is induced. Presented findings have important implications for all studies in which the spatial dimension of pain is measured. When the area or separation between nociceptive stimulation increases, pain does not increase linearly and the pattern of the pain increase is a result of the interaction between intensity and the number of nociceptive sites. A power function should be considered when predicting the size of a nociceptive source.
Collapse
|
5
|
Cataldo A, Ferrè ER, Haggard P. Thermonociceptive interaction: interchannel pain modulation occurs before intrachannel convergence of warmth. J Neurophysiol 2019; 121:1798-1808. [PMID: 30864857 DOI: 10.1152/jn.00341.2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nonnoxious warmth reduces both perceived pain intensity and the amplitude of EEG markers of pain. However, the spatial properties of thermonociceptive interaction, and the level of sensory processing at which it occurs, remain unclear. We investigated whether interchannel warmth-pain interactions occur before or after intrachannel spatial summation of warmth. Warm stimuli were applied to the fingers of the right hand. Their number and location were manipulated in different conditions. A concomitant noxious test pulse was delivered to the middle finger using a CO2 laser. We replicated the classical suppressive effect of warmth on both perceived pain intensity and EEG markers. Importantly, inhibition of pain was not affected by the location and the number of thermal stimuli, even though they increased the perceived intensity of warmth. Our results therefore suggest that the inhibitory effect of warmth on pain is not somatotopically organized. The results also rule out the possibility that warmth affects nociceptive processing after intrachannel warmth summation. NEW & NOTEWORTHY We used spatial summation of warmth as a model to investigate thermonociceptive interactions. Painful CO2 laser pulses were delivered during different thermal conditions. We found that warmth inhibited pain regardless of its location. Crucially, spatial summation of multiple warm stimuli did not further inhibit pain. These findings suggest that warmth-pain interaction occurs independently of or after spatial summation of warmth.
Collapse
Affiliation(s)
- Antonio Cataldo
- Institute of Cognitive Neuroscience, University College London , London , United Kingdom.,Centre for Studies and Research in Cognitive Neuroscience, Alma Mater Studiorum - University of Bologna , Cesena , Italy.,Institute of Philosophy, University of London , London , United Kingdom
| | - Elisa Raffaella Ferrè
- Department of Psychology, Royal Holloway University of London , Surrey , United Kingdom
| | - Patrick Haggard
- Institute of Cognitive Neuroscience, University College London , London , United Kingdom.,Institute of Philosophy, University of London , London , United Kingdom
| |
Collapse
|
6
|
Scarabelot VL, de Oliveira C, Medeiros LF, de Macedo IC, Cioato SG, Adachi LNS, Paz AH, de Souza A, Caumo W, Torres ILS. Transcranial direct-current stimulation reduces nociceptive behaviour in an orofacial pain model. J Oral Rehabil 2018; 46:40-50. [PMID: 30281821 DOI: 10.1111/joor.12726] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 09/17/2018] [Accepted: 09/26/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND Transcranial direct-current stimulation (tDCS) is a noninvasive method of brain stimulation suggested as a therapeutic tool for pain and is related to the reversal of maladaptive plasticity associated with chronic pain. OBJECTIVES This study investigated the effect of tDCS, a non-pharmacological therapy, on local mechanical hyperalgesia, and remote thermal hyperalgesia in rats submitted to orofacial inflammatory pain model, by facial von Frey and hot plate tests, respectively. In addition, we evaluated levels of BDNF, NGF, IL-10 and IL-6 in the brainstem and blood serum of these animals at 24 hours and 7 days after the end of tDCS treatment. METHODS Rats were subjected to temporomandibular joint pain and treated with tDCS. The animals were divided into control, pain and pain + treatment groups. Mechanical and thermal hyperalgesia were evaluated at baseline, 7 days after administration of complete Freund's adjuvant, and immediately, 24 hours, and 7 days after the tDCS treatment. Neuroimmunomodulators levels were determined by ELISA. Statistical analyses were performed by (GEE)/Bonferroni (behavioural tests), three-way ANOVA/SNK (neurochemical tests) and Kruskal-Wallis (histological analysis). RESULTS Transcranial direct-current stimulation reduced mechanical and thermal hyperalgesia (P < 0.01). We observed interaction between factors (pain and treatment) increasing brainstem BDNF (P < 0.01) and NGF (P < 0.05) levels. Furthermore, we found an increase in IL-6 and IL-10 levels in the brainstem at 24 hours and 7 days after tDCS, respectively. CONCLUSION We showed that tDCS reduces thermal and mechanical hyperalgesia induced by orofacial pain until 7 days after treatment. These findings demonstrate that tDCS was effective in the control of orofacial inflammatory pain.
Collapse
Affiliation(s)
- Vanessa L Scarabelot
- Post-Graduate Program in Biological Sciences: Physiology, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Laboratory of Pain Pharmacology and Neuromodulation: Pre-clinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Carla de Oliveira
- Laboratory of Pain Pharmacology and Neuromodulation: Pre-clinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Liciane F Medeiros
- Laboratory of Pain Pharmacology and Neuromodulation: Pre-clinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Isabel C de Macedo
- Post-Graduate Program in Biological Sciences: Physiology, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Laboratory of Pain Pharmacology and Neuromodulation: Pre-clinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Stefania G Cioato
- Laboratory of Pain Pharmacology and Neuromodulation: Pre-clinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Lauren Naomi S Adachi
- Laboratory of Pain Pharmacology and Neuromodulation: Pre-clinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Ana Helena Paz
- Morphological Sciences Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Andressa de Souza
- Laboratory of Pain Pharmacology and Neuromodulation: Pre-clinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Wolnei Caumo
- Department of Surgery in Medical School, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Iraci L S Torres
- Post-Graduate Program in Biological Sciences: Physiology, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Laboratory of Pain Pharmacology and Neuromodulation: Pre-clinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| |
Collapse
|
7
|
Fardo F, Finnerup NB, Haggard P. Organization of the Thermal Grill Illusion by Spinal Segments. Ann Neurol 2018; 84:463-472. [PMID: 30063258 PMCID: PMC6175302 DOI: 10.1002/ana.25307] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 07/23/2018] [Accepted: 07/25/2018] [Indexed: 12/31/2022]
Abstract
Objective A common symptom of neuropathy is the misperception of heat and pain from cold stimuli. Similar cold allodynic sensations can be experimentally induced using the thermal grill illusion (TGI) in humans. It is currently unclear whether this interaction between thermosensory and nociceptive signals depends on spinal or supraspinal integration mechanisms. To address this issue, we developed a noninvasive protocol to assess thermosensory integration across spinal segments. Methods We leveraged anatomical knowledge regarding dermatomes and their spinal projections to investigate potential contributions of spinal integration to the TGI. We simultaneously stimulated a pair of skin locations on the arm or lower back using 1 cold (∼20°C) and 1 warm thermode (∼40°C). The 2 thermodes were always separated by a fixed physical distance on the skin, but elicited neural activity across a varying number of spinal segments, depending on which dermatomal boundaries the 2 stimuli spanned. Results Participants consistently overestimated the actual cold temperature on the skin during combined cold and warm stimulation, confirming the TGI effect. The TGI was present when cold and warm stimuli were delivered within the same dermatome, or across dermatomes corresponding to adjacent spinal segments. In striking contrast, no TGI effect was found when cold and warm stimuli projected to nonadjacent spinal segments. Interpretation These results demonstrate that the strength of the illusion is modulated by the segmental distance between cold and warm afferents. This suggests that both temperature perception and thermal–nociceptive interactions depend upon low‐level convergence mechanisms operating within a single spinal segment and its immediate neighbors. Ann Neurol 2018;84:463–472
Collapse
Affiliation(s)
- Francesca Fardo
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom.,Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Interacting Minds Center, Aarhus University, Aarhus, Denmark
| | - Nanna Brix Finnerup
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Patrick Haggard
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom
| |
Collapse
|
8
|
Olesen AE, Nissen TD, Nilsson M, Lelic D, Brock C, Christrup LL, Drewes AM. Offset Analgesia and The Impact of Treatment with Oxycodone and Venlafaxine: A Placebo-Controlled, Randomized Trial in Healthy Volunteers. Basic Clin Pharmacol Toxicol 2018; 123:727-731. [DOI: 10.1111/bcpt.13078] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 06/20/2018] [Indexed: 01/03/2023]
Affiliation(s)
- Anne E. Olesen
- Mech-Sense; Department of Gastroenterology & Hepatology; Aalborg University Hospital; Aalborg Denmark
- Department of Clinical Medicine; Aalborg University; Aalborg Denmark
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - Thomas D. Nissen
- Mech-Sense; Department of Gastroenterology & Hepatology; Aalborg University Hospital; Aalborg Denmark
| | - Matias Nilsson
- Mech-Sense; Department of Gastroenterology & Hepatology; Aalborg University Hospital; Aalborg Denmark
| | - Dina Lelic
- Mech-Sense; Department of Gastroenterology & Hepatology; Aalborg University Hospital; Aalborg Denmark
| | - Christina Brock
- Mech-Sense; Department of Gastroenterology & Hepatology; Aalborg University Hospital; Aalborg Denmark
- Department of Clinical Medicine; Aalborg University; Aalborg Denmark
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - Lona L. Christrup
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - Asbjørn M. Drewes
- Mech-Sense; Department of Gastroenterology & Hepatology; Aalborg University Hospital; Aalborg Denmark
- Department of Clinical Medicine; Aalborg University; Aalborg Denmark
| |
Collapse
|
9
|
Abstract
Spatial summation of pain (SSP) is the increase of perceived intensity that occurs as the stimulated area increases. Spatial summation of pain is subadditive in that increasing the stimulus area produces a disproportionately small increase in the perceived intensity of pain. A possible explanation for subadditive summation may be that convergent excitatory information is modulated by lateral inhibition. To test the hypothesis that lateral inhibition may limit SSP, we delivered different patterns of noxious thermal stimuli to the abdomens of 15 subjects using a computer-controlled CO2 laser. Lines (5 mm wide) of variable lengths (4, 8 cm) were compared with 2-point stimuli delivered at the same position/separation as the length of lines. When compared with one-point control stimuli, 2-point stimulus patterns produced statistically significant SSP, while no such summation was detected during line stimulus patterns. Direct comparison of pain intensity evoked by 2-point pattern stimuli with line pattern stimuli revealed that 2-point patterns were perceived as significantly more painful, despite the fact that the 2-point pattern stimulated far smaller areas of skin. Thus, the stimulation of the skin region between the endpoints of the lines appears to produce inhibition. These findings indicate that lateral inhibition limits SSP and is an intrinsic component of nociceptive information processing. Disruption of such lateral inhibition may contribute substantially to the radiation of some types of chronic pain.
Collapse
|
10
|
|
11
|
Mindfulness Meditation-Based Pain Relief Employs Different Neural Mechanisms Than Placebo and Sham Mindfulness Meditation-Induced Analgesia. J Neurosci 2016; 35:15307-25. [PMID: 26586819 DOI: 10.1523/jneurosci.2542-15.2015] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
UNLABELLED Mindfulness meditation reduces pain in experimental and clinical settings. However, it remains unknown whether mindfulness meditation engages pain-relieving mechanisms other than those associated with the placebo effect (e.g., conditioning, psychosocial context, beliefs). To determine whether the analgesic mechanisms of mindfulness meditation are different from placebo, we randomly assigned 75 healthy, human volunteers to 4 d of the following: (1) mindfulness meditation, (2) placebo conditioning, (3) sham mindfulness meditation, or (4) book-listening control intervention. We assessed intervention efficacy using psychophysical evaluation of experimental pain and functional neuroimaging. Importantly, all cognitive manipulations (i.e., mindfulness meditation, placebo conditioning, sham mindfulness meditation) significantly attenuated pain intensity and unpleasantness ratings when compared to rest and the control condition (p < 0.05). Mindfulness meditation reduced pain intensity (p = 0.032) and pain unpleasantness (p < 0.001) ratings more than placebo analgesia. Mindfulness meditation also reduced pain intensity (p = 0.030) and pain unpleasantness (p = 0.043) ratings more than sham mindfulness meditation. Mindfulness-meditation-related pain relief was associated with greater activation in brain regions associated with the cognitive modulation of pain, including the orbitofrontal, subgenual anterior cingulate, and anterior insular cortex. In contrast, placebo analgesia was associated with activation of the dorsolateral prefrontal cortex and deactivation of sensory processing regions (secondary somatosensory cortex). Sham mindfulness meditation-induced analgesia was not correlated with significant neural activity, but rather by greater reductions in respiration rate. This study is the first to demonstrate that mindfulness-related pain relief is mechanistically distinct from placebo analgesia. The elucidation of this distinction confirms the existence of multiple, cognitively driven, supraspinal mechanisms for pain modulation. SIGNIFICANCE STATEMENT Recent findings have demonstrated that mindfulness meditation significantly reduces pain. Given that the "gold standard" for evaluating the efficacy of behavioral interventions is based on appropriate placebo comparisons, it is imperative that we establish whether there is an effect supporting meditation-related pain relief above and beyond the effects of placebo. Here, we provide novel evidence demonstrating that mindfulness meditation produces greater pain relief and employs distinct neural mechanisms than placebo cream and sham mindfulness meditation. Specifically, mindfulness meditation-induced pain relief activated higher-order brain regions, including the orbitofrontal and cingulate cortices. In contrast, placebo analgesia was associated with decreased pain-related brain activation. These findings demonstrate that mindfulness meditation reduces pain through unique mechanisms and may foster greater acceptance of meditation as an adjunct pain therapy.
Collapse
|
12
|
Exogenously induced brain activation regulates neuronal activity by top-down modulation: conceptualized model for electrical brain stimulation. Exp Brain Res 2015; 233:1377-89. [DOI: 10.1007/s00221-015-4212-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 01/22/2015] [Indexed: 12/23/2022]
|
13
|
Spatial Summation of Pain in Humans Investigated Using Transcutaneous Electrical Stimulation. THE JOURNAL OF PAIN 2015; 16:11-8. [DOI: 10.1016/j.jpain.2014.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 09/24/2014] [Accepted: 10/08/2014] [Indexed: 01/02/2023]
|
14
|
Andresen T, Nilsson M, Nielsen AK, Lassen D, Arendt-Nielsen L, Drewes AM. Intradermal Injection with Nerve Growth Factor: A Reproducible Model to Induce Experimental Allodynia and Hyperalgesia. Pain Pract 2014; 16:12-23. [PMID: 25470218 DOI: 10.1111/papr.12267] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 10/10/2014] [Indexed: 01/17/2023]
Abstract
BACKGROUND Nerve growth factor (NGF) plays a pivotal role in survival, growth, and differentiation of the nervous system. Increased levels of NGF have been reported in human pain disorders. Experimental injection of NGF in humans is known to evoke long-lasting mechanical sensitization and subsequent allodynia and hyperalgesia. METHODS Reproducibility of intradermal injection of NGF was investigated. Twenty healthy male volunteers were included (mean age 24 years, range 19 to 31). The experiment consisted of 3 identical treatment periods with period 1 stimulating the right arm, period 2 the left arm, and period 3 stimulating the right arm again (period one and three were separated by at least 21 days). Pain intensity was assessed in response to several phasic stimuli in 3 adjacent sites of the volar forearm: pressure; pinprick; brush; and heat before and after NGF injection. Additionally, areas of allodynia and secondary hyperalgesia were assessed. Rekindling with pressure was performed 1 hour and 24 hours after injection. Reproducibility was assessed with intraclass correlation coefficient (ICC 3,1). RESULTS ICC values > 0.6 for all phasic stimuli and for the area of hyperalgesia. After NGF injection, pressure pain (P < 0.001) and heat pain (P < 0.01) sensitivity increased significantly. After rekindling, the area of hyperalgesia (von Frey 26 g) was significantly increased (P = 0.03) and sensitivity to pinprick was increased (P < 0.02). CONCLUSION Intradermal NGF injection is capable of inducing reproducible allodynia and hyperalgesia, and the model is recommended for future experimental and pharmacological pain studies.
Collapse
Affiliation(s)
- Trine Andresen
- Department of Gastroenterology & Hepatology, Center of Mech-Sense, Aalborg University Hospital, Aalborg, Denmark
| | - Matias Nilsson
- Department of Gastroenterology & Hepatology, Center of Mech-Sense, Aalborg University Hospital, Aalborg, Denmark
| | - Anders Klitgaard Nielsen
- Department of Gastroenterology & Hepatology, Center of Mech-Sense, Aalborg University Hospital, Aalborg, Denmark
| | - Dorte Lassen
- Department of Gastroenterology & Hepatology, Center of Mech-Sense, Aalborg University Hospital, Aalborg, Denmark
| | - Lars Arendt-Nielsen
- Department of Health Science and Technology, Center for Sensory-Motor Interactions (SMI), Aalborg University, Aalborg, Denmark
| | - Asbjørn Mohr Drewes
- Department of Gastroenterology & Hepatology, Center of Mech-Sense, Aalborg University Hospital, Aalborg, Denmark.,Department of Health Science and Technology, Center for Sensory-Motor Interactions (SMI), Aalborg University, Aalborg, Denmark
| |
Collapse
|
15
|
Bjerre L, Andersen A, Hagelskjær M, Ge N, Mørch C, Andersenl O. Dynamic tuning of human withdrawal reflex receptive fields during cognitive attention and distraction tasks. Eur J Pain 2012; 15:816-21. [DOI: 10.1016/j.ejpain.2011.01.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 12/14/2010] [Accepted: 01/31/2011] [Indexed: 10/18/2022]
Affiliation(s)
- L. Bjerre
- Center for Sensory‐Motor Interaction, Department of Health Science and Technology, Aalborg University, Denmark
| | - A.T. Andersen
- Center for Sensory‐Motor Interaction, Department of Health Science and Technology, Aalborg University, Denmark
| | - M.T. Hagelskjær
- Center for Sensory‐Motor Interaction, Department of Health Science and Technology, Aalborg University, Denmark
| | - N. Ge
- Center for Sensory‐Motor Interaction, Department of Health Science and Technology, Aalborg University, Denmark
| | - C.D. Mørch
- Center for Sensory‐Motor Interaction, Department of Health Science and Technology, Aalborg University, Denmark
| | - O.K. Andersenl
- Center for Sensory‐Motor Interaction, Department of Health Science and Technology, Aalborg University, Denmark
| |
Collapse
|
16
|
Differential effects of experimental central sensitization on the time-course and magnitude of offset analgesia. Pain 2011; 153:463-472. [PMID: 22154333 DOI: 10.1016/j.pain.2011.11.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 10/28/2011] [Accepted: 11/07/2011] [Indexed: 11/21/2022]
Abstract
Pain perception is temporally altered during states of chronic pain and acute central sensitization; however, the mechanisms contributing to temporal processing of nociceptive information remain poorly understood. Offset analgesia is a phenomenon that reflects the presence of temporal contrast mechanisms for nociceptive information and can provide an end point to study temporal aspects of pain processing. In order to investigate whether offset analgesia is disrupted during sensitized states, 23 healthy volunteers provided real-time continuous visual analogue scale responses to noxious heat stimuli that evoke offset analgesia. Responses to these stimuli were evaluated during capsaicin-heat sensitization (45°C stimulus, capsaicin cream 0.1%) and heat-only sensitization (40°C stimulus, placebo cream). Capsaicin-heat sensitization produced significantly larger regions of secondary mechanical allodynia compared to heat-only sensitization. Although areas of mechanical allodynia were positively related to individual differences in heat pain sensitivity, this relationship was altered at later time points after capsaicin-heat sensitization. Heat hyperalgesia was observed in the secondary region following both capsaicin-heat and heat-only sensitization. Increased latencies to maximal offset analgesia and prolonged aftersensations were observed only in the primary regions directly treated by capsaicin-heat or heat alone. However, contrary to the hypothesis that offset analgesia would be reduced following capsaicin-heat sensitization, the magnitude of offset analgesia remained remarkably intact after both capsaicin-heat and heat-only sensitization in zones of both primary and secondary mechanical allodynia. These data indicate that offset analgesia is a robust phenomenon and engages mechanisms that interact minimally with those supporting acute central sensitization.
Collapse
|
17
|
Mørch CD, Andersen OK, Quevedo AS, Arendt-Nielsen L, Coghill RC. Exteroceptive aspects of nociception: insights from graphesthesia and two-point discrimination. Pain 2010; 151:45-52. [PMID: 20541867 DOI: 10.1016/j.pain.2010.05.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 04/05/2010] [Accepted: 05/18/2010] [Indexed: 01/13/2023]
Abstract
The exteroceptive capabilities of the nociceptive system have long been thought to be considerably more limited than those of the tactile system. However, most investigations of spatio-temporal aspects of the nociceptive system have largely focused on intensity coding as consequence of spatial or temporal summation. Graphesthesia, the identification of numbers "written" on the skin, and assessment of the two-point discrimination thresholds were used to compare the exteroceptive capabilities of the tactile and nociceptive systems. Numbers were "written" on the forearm and the abdomen by tactile stimulation and by painful non-contact infrared laser heat stimulation. Subjects performed both graphesthesia tasks better than chance. The tactile graphesthesia tasks were performed with 89% (82-97%) correct responses on the forearm and 86% (79-94%) correct responses on the abdomen. Tactile graphesthesia tasks were significantly better than painful heat graphesthesia tasks that were performed with 31% (23-40%) and 44% (37-51%) correct responses on the forearm and abdomen, respectively. These findings demonstrate that the central nervous system is capable of assembling complex spatio-temporal patterns of nociceptive information from the body surface into unified mental objects with sufficient accuracy to enable behavioral discrimination.
Collapse
Affiliation(s)
- Carsten Dahl Mørch
- Center for Sensory-Motor Interaction, Health Science and Technology, Aalborg University, Fredrik Bajersvej 7, D3, DK-9220 Aalborg, Denmark Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | | | | | | | | |
Collapse
|
18
|
Quevedo AS, Coghill RC. Filling-in, spatial summation, and radiation of pain: evidence for a neural population code in the nociceptive system. J Neurophysiol 2009; 102:3544-53. [PMID: 19759320 DOI: 10.1152/jn.91350.2008] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The receptive field organization of nociceptive neurons suggests that noxious information may be encoded by population-based mechanisms. Electrophysiological evidence of population coding mechanisms has remained limited. However, psychophysical studies examining interactions between multiple noxious stimuli can provide indirect evidence that neuron population recruitment can contribute to both spatial and intensity-related percepts of pain. In the present study, pairs of thermal stimuli (35 degrees C/49 degrees C or 49 degrees C/49 degrees C) were delivered at different distances on the leg (0, 5, 10, 20, 40 cm) and abdomen (within and across dermatomes) and subjects evaluated pain intensity and perceived spatial attributes of stimuli. Reports of perceived pain spreading to involve areas that were not stimulated (radiation of pain) were most frequent at 5- and 10-cm distances (chi(2) = 34.107, P < 0.0001). Perceived connectivity between two noxious stimuli (filling-in) was influenced by the distance between stimuli (chi(2) = 16.756, P < 0.01), with the greatest connectivity reported at 5- and 10-cm separation distances. Spatial summation of pain occurred over probe separation distances as large as 40 cm and six dermatomes (P < 0.05), but was maximal at 5- and 10-cm separation distances. Taken together, all three of these phenomena suggest that interactions between recruited populations of neurons may support both spatial and intensity-related dimensions of the pain experience.
Collapse
Affiliation(s)
- Alexandre S Quevedo
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1010, USA
| | | |
Collapse
|
19
|
Attentional modulation of spatial integration of pain: evidence for dynamic spatial tuning. J Neurosci 2007; 27:11635-40. [PMID: 17959806 DOI: 10.1523/jneurosci.3356-07.2007] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In many sensory modalities, afferent processing is dynamically modulated by attention and this modulation produces altered sensory experiences. Attention is able to alter perceived pain, but the mechanisms involved in this modulation have not been elucidated. To determine whether attention alters spatial integration of nociceptive information, subjects were recruited to evaluate pain from pairs of noxious/innocuous thermal stimuli during different spatial attentional tasks. Divided attention was able to abolish spatial summation and produce inhibition of pain. In contrast, directed attention enhanced pain intensity by partially integrating both stimuli. This dynamic modulation of spatial integration indicates that attention alters spatial dimensions of afferent nociceptive processing to optimize the perceptual response to input from a particular body region or stimulus feature. This dynamic spatial tuning of nociceptive processing provides a new conceptual insight into the functional significance of endogenous pain inhibitory and facilitatory mechanisms.
Collapse
|
20
|
Yelle MD, Rogers JM, Robert C. C. Offset analgesia: a temporal contrast mechanism for nociceptive information. Pain 2007; 134:174-86. [PMID: 17533118 PMCID: PMC2213795 DOI: 10.1016/j.pain.2007.04.014] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Revised: 02/22/2007] [Accepted: 04/10/2007] [Indexed: 11/17/2022]
Abstract
Temporal filtering of afferent information is an intrinsic component of the processing of numerous types of sensory information. To date, no temporal filtering mechanism has been identified for nociceptive information. The phenomenon of offset analgesia, the disproportionately large decrease in perceived pain following slight decreases in noxious thermal intensity, however, suggests the existence of such a mechanism. To test the hypothesis that a temporal filtering mechanism is engaged during noxious stimulus offset, subjects rated heat pain intensity while stimulus fall rates were varied from -0.5 to -5.0 degrees C/s. In the absence of a temporal filtering mechanism, pain intensity would be expected to decrease in direct proportion to the stimulus fall rate. However, psychophysical fall rates were considerably faster than stimulus fall rates, such that subjects reported no pain while stimulus temperatures were clearly within the noxious range (47.2 degrees C). In addition, paired noxious stimuli were presented simultaneously to determine if offset analgesia evoked by one stimulus could inhibit pain arising from a separate population of primary afferent neurons. Pain ratings were significantly lower than those reported from two constant 49 degrees C stimuli when offset analgesia was induced proximal to, but not distal to, a second noxious stimulus. These asymmetric spatial interactions are not readily explained by peripheral mechanisms. Taken together, these findings indicate that offset analgesia is mediated in part by central mechanisms and reflect a temporal filtering of the sensory information that enhances the contrast of dynamic decreases in noxious stimulus intensity.
Collapse
Affiliation(s)
- Marc D. Yelle
- Wake Forest School of Medicine, Dept. of Neurobiology and Anatomy, Medical Center Blvd., Winston-Salem, NC 27157,
| | - June M. Rogers
- Wake Forest School of Medicine, Dept. of Neurobiology and Anatomy, Medical Center Blvd., Winston-Salem, NC 27157
| | - Coghill Robert C.
- Wake Forest School of Medicine, Dept. of Neurobiology and Anatomy, Medical Center Blvd., Winston-Salem, NC 27157, , 336.716.0302 (Office), 336.716.4534 (Fax)
| |
Collapse
|