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Laser evoked potentials

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https://www.readbyqxmd.com/read/29042004/quantitative-functional-mri-and-neurophysiological-markers-in-a-case-of-gerstmann-str%C3%A3-ussler-scheinker-syndrome
#1
Silvia Marino, Rosa Morabito, S De Salvo, L Bonanno, A Bramanti, P Pollicino, R Giorgianni, Placido Bramanti
Gerstmann-Sträussler-Scheinker syndrome (GSS) is an inherited autosomal dominant prion disease, caused by a codon 102 proline to leucine substitution (P102L) in the prion protein gene (PRNP). We describe the case of a 40-year-old male, affected by a slowly progressive gait disturbance, leg weakness and cognitive impairment. Genomic DNA revealed a point mutation of PRNP at codon 102, resulting in P102L, and the diagnosis of GSS was confirmed. Somatosensory evoked potentials showed alterations of principal parameters, particularly in the right upper and lower limbs...
July 2017: Functional Neurology
https://www.readbyqxmd.com/read/29032189/laser-evoked-potentials-in-painful-radiculopathy
#2
P Hüllemann, C von der Brelie, G Manthey, J Düsterhöft, A K Helmers, M Synowitz, J Gierthmühlen, R Baron
OBJECTIVE: The aims of this exploratory study were (1) to develop a standardized objective electrophysiological technique with laser-evoked potentials to assess dorsal root damage quantitatively and (2) to correlate these LEP measures with clinical parameters and sensory abnormalities (QST) in the affected dermatome. METHODS: Thirty-eight patients with painful radiculopathy and 20 healthy subjects were investigated with LEP recorded from the affected dermatome and control areas as well as with quantitative sensory testing...
September 28, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28972125/sub-millisecond-optogenetic-control-of-neuronal-firing-with-two-photon-holographic-photoactivation-of-chronos
#3
E Ronzitti, R Conti, V Zampini, D Tanese, A J Foust, N Klapoetke, E S Boyden, E Papagiakoumou, V Emiliani
Optogenetic neuronal network manipulation promises to unravel a long-standing mystery in neuroscience: how does microcircuit activity causally relate to behavioral and pathological states? The challenge to evoke spikes with high spatial and temporal complexity necessitates further joint development of light-delivery approaches and custom opsins. Two-photon light-targeting strategies demonstrated, in-depth generation of action potentials in photosensitive neurons both in-vitro and in-vivo, but thus far lack the temporal precision necessary to induce precisely timed spiking events...
October 2, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28971336/habituation-of-laser-evoked-potentials-by-migraine-phase-a-blinded-longitudinal-study
#4
Martin Uglem, Petter Moe Omland, Marit Stjern, Gøril Bruvik Gravdahl, Trond Sand
BACKGROUND: Migraineurs seem to have cyclic variations in cortical excitability in several neurophysiological modalities. Laser-evoked potentials (LEP) are of particular interest in migraine because LEP specifically targets pain pathways, and studies have reported different LEP-changes both between and during headaches. Our primary aim was to explore potential cyclic variations in LEP amplitude and habituation in more detail with a blinded longitudinal study design. METHODS: We compared N1 and N2P2 amplitudes and habituation between two blocks of laser stimulations to the dorsal hand, obtained from 49 migraineurs with four sessions each...
October 2, 2017: Journal of Headache and Pain
https://www.readbyqxmd.com/read/28935423/a-comparison-between-the-neural-correlates-of-laser-and-electric-pain-stimulation-and-their-modulation-by-expectation
#5
E J Hird, A K P Jones, D Talmi, W El-Deredy
BACKGROUND: Pain is modulated by expectation. Event-related potential (ERP) studies of the influence of expectation on pain typically utilise laser heat stimulation to provide a controllable nociceptive-specific stimulus. Painful electric stimulation has a number of practical advantages, but is less nociceptive-specific. We compared the modulation of electric versus laser-evoked pain by expectation, and their corresponding pain-evoked and anticipatory ERPs. NEW METHOD: We developed understanding of recognised methods of laser and electric stimulation...
September 19, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28925006/evidence-based-source-modeling-of-nociceptive-cortical-responses-a-direct-comparison-of-scalp-and-intracranial-activity-in-humans
#6
Claire Bradley, Hélène Bastuji, Luis Garcia-Larrea
BACKGROUND: Source modeling of EEG traditionally relies on interplay between physiological hypotheses and mathematical estimates. We propose to optimize the process by using evidence gathered from brain imaging and intracortical recordings. METHODS: We recorded laser-evoked potentials in 18 healthy participants, using high-density EEG. Brain sources were modeled during the first second poststimulus, constraining their initial position to regions where nociceptive-related activity has been ascertained by intracranial EEG...
September 18, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28899650/micropatterned-surface-electrode-for-massive-selective-stimulation-of-intraepidermal-nociceptive-fibres
#7
Massimo Leandri, Lucio Marinelli, Antonio Siri, Luca Pellegrino
BACKGROUND: No satisfactory neurophysiological test for nociceptive afferents is available to date. Laser stimuli present risks of skin damage, whilst electrical stimulation through specially designed electrodes is not selective enough. NEW METHOD: We present a new electrode designed according to critical issues identified in preliminary computer simulations concerning electric field gradient through the skin. To provide selective stimulation the activating electric field must be limited to intraepidermal free nerve endings...
September 9, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28898491/skin-denervation-does-not-alter-cortical-potentials-to-surface-concentric-electrode-stimulation-a-comparison-with-laser-evoked-potentials-and-contact-heat-evoked-potentials
#8
S La Cesa, G Di Stefano, C Leone, A Pepe, E Galosi, F Alu, A Fasolino, G Cruccu, M Valeriani, A Truini
BACKGROUND: In the neurophysiological assessment of patients with neuropathic pain, laser evoked potentials (LEPs), contact heat evoked potentials (CHEPs) and the evoked potentials by the intraepidermal electrical stimulation via concentric needle electrode are widely agreed as nociceptive specific responses; conversely, the nociceptive specificity of evoked potentials by surface concentric electrode (SE-PREPs) is still debated. METHODS: In this neurophysiological study we aimed at verifying the nociceptive specificity of SE-PREPs...
September 12, 2017: European Journal of Pain: EJP
https://www.readbyqxmd.com/read/28865377/assessing-pain-in-patients-with-chronic-disorders-of-consciousness-are-we-heading-in-the-right-direction
#9
Antonino Naro, Placido Bramanti, Alessia Bramanti, Rocco Salvatore Calabrò
The deterioration of sensory-motor integration within the pain matrix in patients with chronic Disorders of Consciousness (DoC) is one of the principal mechanisms responsible for non-conscious pain perception. The present study aimed to assess whether the variability in the inter-peak interval (IPI) between the N2 and P2 components of laser evoked potentials (LEP) could represent an objective marker of the behavioral responsiveness to nociceptive stimulation, as measured by the Nociception Coma Scale-Revised (NCS-R), and regardless of the sensory part of pain processing...
October 2017: Consciousness and Cognition
https://www.readbyqxmd.com/read/28859860/visual-reminders-of-death-enhance-nociceptive-related-cortical-responses-and-event-related-alpha-desynchronisation
#10
Elia Valentini, Valentina Nicolardi, Salvatore Maria Aglioti
Previous research suggests that prompting individuals to think on their own mortality affects their perception of painful somatic stimuli and related brain activity. Grounded on the assumption that reminders of mortality may recruit threat-defence mechanisms similar to the ones activated by painful nociceptive stimuli, we hypothesize that the effects exerted by linguistic reminders of death on pain perception and brain activity would be elicited by passive observation of death-related pictures vs. more generic threat-related pictures...
August 30, 2017: Biological Psychology
https://www.readbyqxmd.com/read/28856913/effects-of-external-trigeminal-nerve-stimulation-etns-on-laser-evoked-cortical-potentials-lep-a-pilot-study-in-migraine-patients-and-controls
#11
Eleonora Vecchio, Eleonora Gentile, Giovanni Franco, Katia Ricci, Marina de Tommaso
Background Transcutaneous external supraorbital nerve stimulation has emerged as a treatment option for primary headache disorders, though its action mechanism is still unclear. Study aim In this randomized, sham-controlled pilot study we aimed to test the effects of a single external transcutaneous nerve stimulation session on pain perception and cortical responses induced by painful laser stimuli delivered to the right forehead and the right hand in a cohort of migraine without aura patients and healthy controls...
January 1, 2017: Cephalalgia: An International Journal of Headache
https://www.readbyqxmd.com/read/28855885/laser-doppler-assessment-of-vasomotor-axon-reflex-responsiveness-to-evaluate-neurovascular-function
#12
REVIEW
Marie Luise Kubasch, Anne Sophie Kubasch, Juliana Torres Pacheco, Sylvia J Buchmann, Ben Min-Woo Illigens, Kristian Barlinn, Timo Siepmann
The vasomotor axon reflex can be evoked in peripheral epidermal nociceptive C-fibers to induce local vasodilation. This neurogenic flare response is a measure of C-fiber functional integrity and therefore shows impairment in patients with small fiber neuropathy. Laser Doppler flowmetry (LDF) and laser Doppler imaging (LDI) are both techniques to analyze vasomotor small fiber function by quantifying the integrity of the vasomotor-mediated axon reflex. While LDF assesses the flare response following acetylcholine iontophoresis with temporal resolution at a single defined skin point, LDI records flare responses with spatial and temporal resolution, generating a two-dimensional map of superficial blood flow...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28803174/intraoperative-vascular-neuromonitoring-in-patients-with-subarachnoid-hemorrhage-a-pilot-study-using-combined-laser-doppler-spectrophotometry
#13
Emilija Schmitz, Barbara Bischoff, Dennis Wolf, Hubert Schmitt, Ilker Y Eyupoglu, Karl Roessler, Michael Buchfelder, Björn Sommer
OBJECTIVE: Intraoperative monitoring of cerebral microcirculation in patients with subarachnoid hemorrhage (SAH) may predict the postoperative neurological outcome. In this pilot study, we examined the value of a novel non-invasive real-time measurement technique to detect changes in local microcirculation. METHODS: We used the laser-Doppler spectrophotometry system "Oxygen-to-see(O2C)" in 14 patients with SAH Hunt & Hess grade 2 to 5, who underwent microsurgical clipping of cerebral aneurysms...
August 9, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28752263/photobiomodulation-therapy-by-nir-laser-in-persistent-pain-an-analytical-study-in-the-rat
#14
Laura Micheli, Lorenzo Di Cesare Mannelli, Elena Lucarini, Francesca Cialdai, Leonardo Vignali, Carla Ghelardini, Monica Monici
Over the past three decades, physicians have used laser sources for the management of different pain conditions obtaining controversial results that call for further investigations. In order to evaluate the pain relieving possibilities of photobiomodulation therapy (PBMT), we tested two near infrared (NIR) laser systems, with different power, against various kinds of persistent hyperalgesia animal models. In rats, articular pain was reproduced by the intra-articular injection of sodium monoiodoacetate (MIA) and complete Freund's adjuvant (CFA), while compressive neuropathy was modelled by the chronic constriction injury of the sciatic nerve (CCI)...
July 28, 2017: Lasers in Medical Science
https://www.readbyqxmd.com/read/28744201/calcium-dynamics-in-basal-dendrites-of-layer-5a-and-5b-pyramidal-neurons-is-tuned-to-the-cell-type-specific-physiological-action-potential-discharge
#15
Patrik Krieger, Christiaan P J de Kock, Andreas Frick
Layer 5 (L5) is a major neocortical output layer containing L5A slender-tufted (L5A-st) and L5B thick-tufted (L5B-tt) pyramidal neurons. These neuron types differ in their in vivo firing patterns, connectivity and dendritic morphology amongst other features, reflecting their specific functional role within the neocortical circuits. Here, we asked whether the active properties of the basal dendrites that receive the great majority of synaptic inputs within L5 differ between these two pyramidal neuron classes...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28665973/negative-expectations-interfere-with-the-analgesic-effect-of-safety-cues-on-pain-perception-by-priming-the-cortical-representation-of-pain-in-the-midcingulate-cortex
#16
Abeer F Almarzouki, Christopher A Brown, Richard J Brown, Matthew H K Leung, Anthony K P Jones
It is well known that the efficacy of treatment effects, including those of placebos, is heavily dependent on positive expectations regarding treatment outcomes. For example, positive expectations about pain treatments are essential for pain reduction. Such positive expectations not only depend on the properties of the treatment itself, but also on the context in which the treatment is presented. However, it is not clear how the preceding threat of pain will bias positive expectancy effects. One hypothesis is that threatening contexts trigger fearful and catastrophic thinking, reducing the pain-relieving effects of positive expectancy...
2017: PloS One
https://www.readbyqxmd.com/read/28614189/dose-response-study-of-topical-allyl-isothiocyanate-mustard-oil-as-a-human-surrogate-model-of-pain-hyperalgesia-and-neurogenic-inflammation
#17
Hjalte H Andersen, Silvia Lo Vecchio, Parisa Gazerani, Lars Arendt-Nielsen
Despite being a ubiquitous animal pain model, the natural TRPA1-agonist allyl isothiocyanate (AITC, also known as "mustard oil") has only been sparsely investigated as a potential human surrogate model of pain, sensitization, and neurogenic inflammation. Its dose-response as an algogenic, sensitizing irritant remains to be elucidated in human skin. Three concentrations of AITC (10%, 50%, and 90%) and vehicle (paraffin) were applied for 5 minutes to 3 × 3 cm areas on the volar forearms in 14 healthy volunteers, and evoked pain intensity (visual analog scale 0-100 mm) and pain quality were assessed...
September 2017: Pain
https://www.readbyqxmd.com/read/28533761/the-frontal-area-with-higher-frequency-response-is-the-principal-feature-of-laser-evoked-potentials-in-rats-with-chronic-inflammatory-pain-a-parallel-factor-analysis-study
#18
Jing Wang, Juan Wang, You Wan, Xiaoli Li
Chronic pain is a pathological developing course of pain. In clinic, an objective indicator is needed for diagnosing and better controlling chronic pain. The abnormal neural responses in chronic pain are reflected by multiple event-related potentials (ERPs) in time, frequency, and location domain, respectively. However, multiple changes in ERPs are not applicable in clinic. So, the principal feature covered the most informative changes extracted from these three domains of ERP during the development of chronic pain is needed...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28527052/action-mechanisms-of-onabotulinum-toxin-a-hints-for-selection-of-eligible-patients
#19
Carlo Lovati, Luca Giani
In the past few decades, the so-feared botulinum toxin has conversely acquired the role of a ever more versatile therapeutic substance, used in an increasing number of pathological situations, including chronic headache and more precisely in the prophylaxis of chronic migraine. The medical use of botulinum toxin allowed to better understand its multiple mechanisms of action. Investigations about the pathophysiology of primary and secondary headaches has shown a series of common biological elements that frequently are also targets of the action of botulinum toxin...
May 2017: Neurological Sciences
https://www.readbyqxmd.com/read/28526914/finite-element-method-simulating-temperature-distribution-in-skin-induced-by-980-nm-pulsed-laser-based-on-pain-stimulation
#20
Han Wang, Xiao-Xi Dong, Ji-Chun Yang, He Huang, Ying-Xin Li, Hai-Xia Zhang
For predicting the temperature distribution within skin tissue in 980-nm laser-evoked potentials (LEPs) experiments, a five-layer finite element model (FEM-5) was constructed based on Pennes bio-heat conduction equation and the Lambert-Beer law. The prediction results of the FEM-5 model were verified by ex vivo pig skin and in vivo rat experiments. Thirty ex vivo pig skin samples were used to verify the temperature distribution predicted by the model. The output energy of the laser was 1.8, 3, and 4.4 J. The laser spot radius was 1 mm...
July 2017: Lasers in Medical Science
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