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De Schoenmacker I, Costa Marques D, Scheuren PS, Lütolf R, Gorrell LM, Mehli SC, Curt A, Rosner J, Hubli M. Novel neurophysiological evidence for preserved pain habituation across chronic pain conditions. Clin Neurophysiol 2024; 166:31-42. [PMID: 39094528 DOI: 10.1016/j.clinph.2024.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 03/26/2024] [Accepted: 07/16/2024] [Indexed: 08/04/2024]
Abstract
OBJECTIVE The present study aimed to investigate whether subjective and objective measures of pain habituation can be used as potential markers for central sensitization across various chronic pain patients. METHODS Two blocks of contact-heat stimuli were applied to a non-painful area in 93 chronic pain patients (low back pain, neuropathic pain, and complex regional pain syndrome) and 60 healthy controls (HC). Habituation of pain ratings, contact-heat evoked potentials (CHEP), and sympathetic skin responses (SSR) was measured. RESULTS There was no significant difference in any measure of pain habituation between patients and HC. Even patients with apparent clinical signs of central sensitization showed no reduced pain habituation. However, prolonged baseline CHEP and SSR latencies (stimulation block 1) were found in patients compared to HC (CHEP: Δ-latency = 23 ms, p = 0.012; SSR: Δ-latency = 100 ms, p = 0.022). CONCLUSION Given the performed multimodal neurophysiological testing protocol, we provide evidence indicating that pain habituation may be preserved in patients with chronic pain and thereby be of limited use as a sensitive marker for central sensitization. These results are discussed within the framework of the complex interactions between pro- and antinociceptive mechanism as well as methodological issues. The prolonged latencies of CHEP and SSR after stimulation in non-painful areas may indicate subclinical changes in the integrity of thermo-nociceptive afferents, or a shift towards antinociceptive activity. This shift could potentially affect the relay of ascending signals. SIGNIFICANCE Our findings challenge the prevailing views in the literature and may encourage further investigations into the peripheral and central components of pain habituation, using advanced multimodal neurophysiological techniques.
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Affiliation(s)
- Iara De Schoenmacker
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland.
| | - David Costa Marques
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Paulina S Scheuren
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada
| | - Robin Lütolf
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Lindsay M Gorrell
- Integrative Spinal Research Group, Department of Chiropractic Medicine, Balgrist University Hospital, University of Zurich, Switzerland
| | - Sarah C Mehli
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jan Rosner
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland; Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Michèle Hubli
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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De Schoenmacker I, Scheuren PS, Sirucek L, Lütolf R, Gorrell LM, Rosner J, Curt A, Schweinhardt P, Hubli M. Understanding inter-individual variability of experimental pain habituation and conditioned pain modulation in healthy individuals. Sci Rep 2024; 14:22070. [PMID: 39333624 PMCID: PMC11436718 DOI: 10.1038/s41598-024-73158-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 09/16/2024] [Indexed: 09/29/2024] Open
Abstract
Although reduced experimental pain habituation is proposed as a proxy of diminished endogenous pain modulatory capacity in chronic pain, prior studies show contradictory findings. Even across healthy participants, pain habituation varies substantially, which may relate to another measure of endogenous pain modulation, i.e., conditioned pain modulation (CPM). Hence, this study investigated the relationship between pain habituation and CPM. Pain habituation was assessed in 45 healthy participants between two blocks of 15-20 contact-heat stimuli applied to the hand. Habituation of subjective pain ratings and objective neurophysiological readouts (contact-heat evoked potential (CHEP) and palmar sympathetic skin response (SSR)) was investigated. CPM was assessed by comparing heat pain thresholds before and after hand immersion in a noxious cold (9 °C) and lukewarm water bath (32 °C, to control for repeated measures effects). Pain habituation showed a large variability, with subjective but not objective pain habituation correlating with cold-induced CPM effects (r = 0.50; p = 0.025). This correlation was not observed for 'true' CPM effects (corrected for repeated measures effects) nor for CPM effects induced by a lukewarm water bath. These findings suggest that the observed variability in subjective pain habituation may be influenced by both descending endogenous pain modulation and peripheral adaptation processes associated with repeated measures. Objective pain habituation readouts, i.e., CHEPs and SSRs, capture different, complementary aspects of endogenous pain modulation.
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Affiliation(s)
- Iara De Schoenmacker
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.
- Biomedical Data Science Lab, Institute of Translational Medicine, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland.
| | - Paulina S Scheuren
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
- Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Laura Sirucek
- Department of Chiropractic Medicine, Integrative Spinal Research Group, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich (ZNZ), Zurich, Switzerland
| | - Robin Lütolf
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Lindsay M Gorrell
- Department of Chiropractic Medicine, Integrative Spinal Research Group, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jan Rosner
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
- Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Petra Schweinhardt
- Department of Chiropractic Medicine, Integrative Spinal Research Group, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Michèle Hubli
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
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In A, Strohman A, Payne B, Legon W. Low-intensity focused ultrasound to the posterior insula reduces temporal summation of pain. Brain Stimul 2024; 17:911-924. [PMID: 39089647 PMCID: PMC11452899 DOI: 10.1016/j.brs.2024.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 07/24/2024] [Accepted: 07/29/2024] [Indexed: 08/04/2024] Open
Abstract
BACKGROUND The insula and dorsal anterior cingulate cortex (dACC) are core brain regions involved in pain processing and central sensitization, a shared mechanism across various chronic pain conditions. Methods to modulate these regions may serve to reduce central sensitization, though it is unclear which target may be most efficacious for different measures of central sensitization. OBJECTIVE/HYPOTHESIS Investigate the effect of low-intensity focused ultrasound (LIFU) to the anterior insula (AI), posterior insula (PI), or dACC on conditioned pain modulation (CPM) and temporal summation of pain (TSP). METHODS N = 16 volunteers underwent TSP and CPM pain tasks pre/post a 10 min LIFU intervention to either the AI, PI, dACC or Sham stimulation. Pain ratings were collected pre/post LIFU. RESULTS Only LIFU to the PI significantly attenuated pain ratings during the TSP protocol. No effects were found for the CPM task for any of the LIFU targets. LIFU pressure modulated group means but did not affect overall group differences. CONCLUSIONS LIFU to the PI reduced temporal summation of pain. This may, in part, be due to dosing (pressure) of LIFU. Inhibition of the PI with LIFU may be a future potential therapy in chronic pain populations demonstrating central sensitization. The minimal effective dose of LIFU for efficacious neuromodulation will help to translate LIFU for therapeutic options.
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Affiliation(s)
- Alexander In
- Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA
| | - Andrew Strohman
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA; Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA; Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Roanoke, VA, 24016, USA
| | - Brighton Payne
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA
| | - Wynn Legon
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA; Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA; Center for Human Neuroscience Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA; Center for Health Behaviors Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA; School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24016, USA; Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Roanoke, VA, 24016, USA; Department of Neurosurgery, Carilion Clinic, Roanoke, VA, 24016, USA.
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Legon W, Strohman A, In A, Payne B. Noninvasive neuromodulation of subregions of the human insula differentially affect pain processing and heart-rate variability: a within-subjects pseudo-randomized trial. Pain 2024; 165:1625-1641. [PMID: 38314779 PMCID: PMC11189760 DOI: 10.1097/j.pain.0000000000003171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 09/25/2023] [Accepted: 09/26/2023] [Indexed: 02/07/2024]
Abstract
ABSTRACT The insula is an intriguing target for pain modulation. Unfortunately, it lies deep to the cortex making spatially specific noninvasive access difficult. Here, we leverage the high spatial resolution and deep penetration depth of low-intensity focused ultrasound (LIFU) to nonsurgically modulate the anterior insula (AI) or posterior insula (PI) in humans for effect on subjective pain ratings, electroencephalographic (EEG) contact heat-evoked potentials, as well as autonomic measures including heart-rate variability (HRV). In a within-subjects, repeated-measures, pseudo-randomized trial design, 23 healthy volunteers received brief noxious heat pain stimuli to the dorsum of their right hand during continuous heart-rate, electrodermal, electrocardiography and EEG recording. Low-intensity focused ultrasound was delivered to the AI (anterior short gyrus), PI (posterior longus gyrus), or under an inert Sham condition. The primary outcome measure was pain rating. Low-intensity focused ultrasound to both AI and PI similarly reduced pain ratings but had differential effects on EEG activity. Low-intensity focused ultrasound to PI affected earlier EEG amplitudes, whereas LIFU to AI affected later EEG amplitudes. Only LIFU to the AI affected HRV as indexed by an increase in SD of N-N intervals and mean HRV low-frequency power. Taken together, LIFU is an effective noninvasive method to individually target subregions of the insula in humans for site-specific effects on brain biomarkers of pain processing and autonomic reactivity that translates to reduced perceived pain to a transient heat stimulus.
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Affiliation(s)
- Wynn Legon
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
- Center for Human Neuroscience Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States
- Center for Health Behaviors Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States
| | - Andrew Strohman
- Virginia Tech Carilion School of Medicine, Roanoke, VA, United States
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Roanoke, VA, United States
| | - Alexander In
- Virginia Tech Carilion School of Medicine, Roanoke, VA, United States
| | - Brighton Payne
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States
- Center for Health Behaviors Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States
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Allmendinger F, Scheuren PS, De Schoenmacker I, Brunner F, Rosner J, Curt A, Hubli M. Contact-Heat Evoked Potentials: Insights into Pain Processing in CRPS Type I. J Pain Res 2024; 17:989-1003. [PMID: 38505501 PMCID: PMC10949273 DOI: 10.2147/jpr.s436645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 02/23/2024] [Indexed: 03/21/2024] Open
Abstract
Purpose The pathophysiological mechanisms underlying the development of chronic pain in complex regional pain syndrome (CRPS) are diverse and involve both peripheral and central changes in pain processing, such as sensitization of the nociceptive system. The aim of this study was to objectively distinguish the specific changes occurring at both peripheral and central levels in nociceptive processing in individuals with chronic CRPS type I. Patients and Methods Nineteen individuals with chronic CRPS type I and 16 age- and sex-matched healthy controls (HC) were recruited. All individuals underwent a clinical examination and pain assessment in the most painful limb, the contralateral limb, and a pain-free control area to distinguish between peripheral and central mechanisms. Contact-heat evoked potentials (CHEPs) were recorded after heat stimulation of the three different areas and amplitudes and latencies were analyzed. Additionally, quantitative sensory testing (QST) was performed in all three areas. Results Compared to HC, CHEP amplitudes in CRPS were only increased after stimulation of the painful area (p=0.025), while no increases were observed for the pain-free control area (p=0.14). None of the CHEP latencies were different between the two cohorts (all p>0.23). Furthermore, individuals with CRPS showed higher pain ratings after stimulation of the painful limb compared to their contralateral limb (p=0.013). Lastly, compared to HC, mechanical (p=0.012) and thermal (p=0.046) sensitivity was higher in the painful area of the CRPS cohort. Conclusion This study provides neurophysiological evidence supporting an intact thermo-nociceptive pathway with signs of peripheral sensitization, such as hyperexcitable primary afferent nociceptors, in individuals with CRPS type I. This is further supported by the observation of mechanical and thermal gain of sensation only in the painful limb. Additionally, the increased CHEP amplitudes might be related to fear-induced alterations of nociceptive processing.
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Affiliation(s)
- Florin Allmendinger
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Paulina Simonne Scheuren
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland
- International Collaboration on Repair Discoveries, Vancouver, BC, Canada
- Department of Anesthesiology, Pharmacology & Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Iara De Schoenmacker
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Florian Brunner
- Department of Physical Medicine and Rheumatology, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jan Rosner
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Michèle Hubli
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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Strohman A, Payne B, In A, Stebbins K, Legon W. Low-Intensity Focused Ultrasound to the Human Dorsal Anterior Cingulate Attenuates Acute Pain Perception and Autonomic Responses. J Neurosci 2024; 44:e1011232023. [PMID: 38182418 PMCID: PMC10883612 DOI: 10.1523/jneurosci.1011-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 01/07/2024] Open
Abstract
The dorsal anterior cingulate cortex (dACC) is a critical brain area for pain and autonomic processing, making it a promising noninvasive therapeutic target. We leverage the high spatial resolution and deep focal lengths of low-intensity focused ultrasound (LIFU) to noninvasively modulate the dACC for effects on behavioral and cardiac autonomic responses using transient heat pain stimuli. A N = 16 healthy human volunteers (6 M/10 F) received transient contact heat pain during either LIFU to the dACC or Sham stimulation. Continuous electroencephalogram (EEG), electrocardiogram (ECG), and electrodermal response (EDR) were recorded. Outcome measures included pain ratings, heart rate variability, EDR response, blood pressure, and the amplitude of the contact heat-evoked potential (CHEP).LIFU reduced pain ratings by 1.09 ± 0.20 points relative to Sham. LIFU increased heart rate variability indexed by the standard deviation of normal sinus beats (SDNN), low-frequency (LF) power, and the low-frequency/high-frequency (LF/HF) ratio. There were no effects on the blood pressure or EDR. LIFU resulted in a 38.1% reduction in the P2 CHEP amplitude. Results demonstrate LIFU to the dACC reduces pain and alters autonomic responses to acute heat pain stimuli. This has implications for the causal understanding of human pain and autonomic processing in the dACC and potential future therapeutic options for pain relief and modulation of homeostatic signals.
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Affiliation(s)
- Andrew Strohman
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Roanoke, VA 24016
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016
| | - Brighton Payne
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016
| | - Alexander In
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016
| | - Katelyn Stebbins
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Roanoke, VA 24016
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016
| | - Wynn Legon
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Roanoke, VA 24016
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016
- Center for Human Neuroscience Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016
- Center for Health Behaviors Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
- Department of Neurosurgery, Virginia Tech Carilion School of Medicine, Roanoke, VA 24016
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Cormie MA, Moayedi M. Selective noninvasive modulation of insular subregions supports differential functions in the pain experience. Pain 2024:00006396-990000000-00506. [PMID: 38314822 DOI: 10.1097/j.pain.0000000000003172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 11/15/2023] [Indexed: 02/07/2024]
Affiliation(s)
- Matthew Alexander Cormie
- Centre for Multimodal Sensorimotor and Pain Research, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - Massieh Moayedi
- Centre for Multimodal Sensorimotor and Pain Research, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
- Division of Clinical and Computational Neuroscience, Krembil Brain Institute, Toronto Western Hospital, University Health Network, Toronto, ON, Canada
- University of Toronto Centre for the Study of Pain, University of Toronto, Toronto, ON, Canada
- Department of Dentistry, Mount Sinai Hospital, Toronto, ON, Canada
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McDaniel AL, Dimitrov TN, Bruehl SP, Monroe TB, Failla MD, Cowan RL, Ryan C, Anderson AR. Psychophysics of Pain: A Methodological Introduction. Pain Manag Nurs 2023; 24:442-451. [PMID: 36948969 PMCID: PMC10440278 DOI: 10.1016/j.pmn.2023.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 12/29/2022] [Accepted: 02/15/2023] [Indexed: 03/24/2023]
Abstract
For over 100 years, psychophysics ..÷ the scientific study between physical stimuli and sensation ... has been successfully employed in numerous scientific and healthcare disciplines, as an objective measure of sensory phenomena. This manuscript provides an overview of fundamental psychophysical concepts, emphasizing pain and research application..÷defining common terms, methods, and procedures.Psychophysics can provide systematic and objective measures of sensory perception that can be used by nursing scientists to explore complex, subjective phenomena..÷such as pain perception. While there needs to be improved standardization of terms and techniques, psychophysical approaches are diverse and may be tailored to address or augment current research paradigms. The interdisciplinary nature of psychophysics..÷like nursing..÷provides a unique lens for understanding how our perceptions are influenced by measurable sensations. While the quest to understand human perception is far from complete, nursing science has an opportunity to contribute to pain research by using the techniques and methods available through psychophysical procedures.
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Affiliation(s)
- Aaron L McDaniel
- From The Ohio State University College of Nursing, Columbus, Ohio.
| | | | - Stephen P Bruehl
- Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Todd B Monroe
- From The Ohio State University College of Nursing, Columbus, Ohio
| | | | - Ronald L Cowan
- Department of Psychiatry, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Claire Ryan
- Vanderbilt University Medical Center, Nashville, Tennessee
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Legon W, Strohman A, In A, Stebbins K, Payne B. Non-invasive neuromodulation of sub-regions of the human insula differentially affect pain processing and heart-rate variability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.05.539593. [PMID: 37205396 PMCID: PMC10187309 DOI: 10.1101/2023.05.05.539593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The insula is a portion of the cerebral cortex folded deep within the lateral sulcus covered by the overlying opercula of the inferior frontal lobe and superior portion of the temporal lobe. The insula has been parsed into sub-regions based upon cytoarchitectonics and structural and functional connectivity with multiple lines of evidence supporting specific roles for each of these sub-regions in pain processing and interoception. In the past, causal interrogation of the insula was only possible in patients with surgically implanted electrodes. Here, we leverage the high spatial resolution combined with the deep penetration depth of low-intensity focused ultrasound (LIFU) to non-surgically modulate either the anterior insula (AI) or posterior insula (PI) in humans for effect on subjective pain ratings, electroencephalographic (EEG) contact head evoked potentials (CHEPs) and time-frequency power as well as autonomic measures including heart-rate variability (HRV) and electrodermal response (EDR). N = 23 healthy volunteers received brief noxious heat pain stimuli to the dorsum of their right hand during continuous heart-rate, EDR and EEG recording. LIFU was delivered to either the AI (anterior short gyrus), PI (posterior longus gyrus) or under an inert sham condition time-locked to the heat stimulus. Results demonstrate that single-element 500 kHz LIFU is capable of individually targeting specific gyri of the insula. LIFU to both AI and PI similarly reduced perceived pain ratings but had differential effects on EEG activity. LIFU to PI affected earlier EEG amplitudes around 300 milliseconds whereas LIFU to AI affected EEG amplitudes around 500 milliseconds. In addition, only LIFU to the AI affected HRV as indexed by an increase in standard deviation of N-N intervals (SDNN) and mean HRV low frequency power. There was no effect of LIFU to either AI or PI on EDR or blood pressure. Taken together, LIFU looks to be an effective method to individually target sub-regions of the insula in humans for site-specific effects on brain biomarkers of pain processing and autonomic reactivity that translates to reduced perceived pain to a transient heat stimulus. These data have implications for the treatment of chronic pain and several neuropsychological diseases like anxiety, depression and addiction that all demonstrate abnormal activity in the insula concomitant with dysregulated autonomic function.
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Affiliation(s)
- Wynn Legon
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
- Center for Human Neuroscience Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA
- Center for Health Behaviors Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA
| | - Andrew Strohman
- Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Roanoke, VA, 24016, USA
| | - Alexander In
- Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA
| | - Katelyn Stebbins
- Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Roanoke, VA, 24016, USA
| | - Brighton Payne
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA
- Center for Health Behaviors Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA
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