The Experts below are selected from a list of 12663 Experts worldwide ranked by ideXlab platform
Adrian Handforth - One of the best experts on this subject based on the ideXlab platform.
-
Vagus Nerve stimulation inhibits harmaline-induced tremor.
Brain research, 2004Co-Authors: Scott E. Krahl, Fredricka C. Martin, Adrian HandforthAbstract:Excessive olivo-cerebellar burst-firing occurs during harmaline-induced tremor. This system receives rich sensory inputs, including visceral. We hypothesized that electrical Vagus Nerve stimulation (VNS) would suppress harmaline tremor, as measured with digitized motion power in the rat. Cervical Vagus Nerve stimulation suppressed power in the 8-12-Hz tremor range by 40%, whereas sham stimulation was ineffective. This study raises the possibility that activation of various sensory modalities, as well as visceral, may reduce tremor.
-
right sided Vagus Nerve stimulation reduces generalized seizure severity in rats as effectively as left sided
Epilepsy Research, 2003Co-Authors: Scott E. Krahl, Shayani S Senanayake, Adrian HandforthAbstract:As currently utilized, Vagus Nerve stimulation (VNS) is applied to the cervical trunk of the left Vagus Nerve to suppress seizures clinically. Demonstration that VNS can also reduce seizure severity when electrodes are placed on the right cervical Vagus Nerve in rats would provide empirical evidence that the antiepileptic effects of VNS are not an exclusive property of the left Vagus Nerve. Rats were implanted with a custom cuff electrode on either the left or right cervical Vagus Nerve. Two days later, continuous VNS was begun in half the rats with left-sided and half with right-sided electrodes. The remaining rats were connected to the stimulator, but did not receive VNS. After 30 s, pentylenetetrazole (PTZ) was administered systemically and seizures were rated by a blinded observer. The PTZ test was repeated two days later, with VNS administered to the previously unstimulated rats, while the others received no stimulation. VNS significantly reduced the severity of PTZ-induced seizures in rats regardless of the side of stimulation as compared to their no-VNS (control condition) seizure severity. No significant differences in efficacy existed based on the side of stimulation. These results indicate that right-sided VNS in rats is just as effective as left-sided VNS, suggesting that fibers necessary for seizure suppression are not unique to the left Vagus Nerve.
-
Suppression of harmaline-induced tremor in rats by Vagus Nerve stimulation.
Movement disorders : official journal of the Movement Disorder Society, 2001Co-Authors: Adrian Handforth, Scott E. KrahlAbstract:We studied whether Vagus Nerve stimulation could suppress tremor in the harmaline tremor model in the rat. Animals were chronically implanted with helical leads around the left Vagus Nerve and a disk-shaped electrode positioned subcutaneously in the dorsal neck. Harmaline-induced tremor was recorded on a physiograph while each animal received a sequence of five 20-minute trials. Each trial consisted of five minutes of pre-stimulation baseline, five minutes of Vagus Nerve stimulation, and ten minutes of post-stimulation. Vagus Nerve stimulation significantly suppressed harmaline-induced tremor. The suppressive effect was present within the first minute of stimulation and was reproducible across the five trials of the study. The results of this study suggest that the central generator or expression of tremor in the harmaline animal model can be suppressed by Vagus Nerve stimulation.
Scott E. Krahl - One of the best experts on this subject based on the ideXlab platform.
-
Vagus Nerve stimulation inhibits harmaline-induced tremor.
Brain research, 2004Co-Authors: Scott E. Krahl, Fredricka C. Martin, Adrian HandforthAbstract:Excessive olivo-cerebellar burst-firing occurs during harmaline-induced tremor. This system receives rich sensory inputs, including visceral. We hypothesized that electrical Vagus Nerve stimulation (VNS) would suppress harmaline tremor, as measured with digitized motion power in the rat. Cervical Vagus Nerve stimulation suppressed power in the 8-12-Hz tremor range by 40%, whereas sham stimulation was ineffective. This study raises the possibility that activation of various sensory modalities, as well as visceral, may reduce tremor.
-
right sided Vagus Nerve stimulation reduces generalized seizure severity in rats as effectively as left sided
Epilepsy Research, 2003Co-Authors: Scott E. Krahl, Shayani S Senanayake, Adrian HandforthAbstract:As currently utilized, Vagus Nerve stimulation (VNS) is applied to the cervical trunk of the left Vagus Nerve to suppress seizures clinically. Demonstration that VNS can also reduce seizure severity when electrodes are placed on the right cervical Vagus Nerve in rats would provide empirical evidence that the antiepileptic effects of VNS are not an exclusive property of the left Vagus Nerve. Rats were implanted with a custom cuff electrode on either the left or right cervical Vagus Nerve. Two days later, continuous VNS was begun in half the rats with left-sided and half with right-sided electrodes. The remaining rats were connected to the stimulator, but did not receive VNS. After 30 s, pentylenetetrazole (PTZ) was administered systemically and seizures were rated by a blinded observer. The PTZ test was repeated two days later, with VNS administered to the previously unstimulated rats, while the others received no stimulation. VNS significantly reduced the severity of PTZ-induced seizures in rats regardless of the side of stimulation as compared to their no-VNS (control condition) seizure severity. No significant differences in efficacy existed based on the side of stimulation. These results indicate that right-sided VNS in rats is just as effective as left-sided VNS, suggesting that fibers necessary for seizure suppression are not unique to the left Vagus Nerve.
-
Suppression of harmaline-induced tremor in rats by Vagus Nerve stimulation.
Movement disorders : official journal of the Movement Disorder Society, 2001Co-Authors: Adrian Handforth, Scott E. KrahlAbstract:We studied whether Vagus Nerve stimulation could suppress tremor in the harmaline tremor model in the rat. Animals were chronically implanted with helical leads around the left Vagus Nerve and a disk-shaped electrode positioned subcutaneously in the dorsal neck. Harmaline-induced tremor was recorded on a physiograph while each animal received a sequence of five 20-minute trials. Each trial consisted of five minutes of pre-stimulation baseline, five minutes of Vagus Nerve stimulation, and ten minutes of post-stimulation. Vagus Nerve stimulation significantly suppressed harmaline-induced tremor. The suppressive effect was present within the first minute of stimulation and was reproducible across the five trials of the study. The results of this study suggest that the central generator or expression of tremor in the harmaline animal model can be suppressed by Vagus Nerve stimulation.
Lorenza S Colzato - One of the best experts on this subject based on the ideXlab platform.
-
transcutaneous Vagus Nerve stimulation tvns enhances divergent thinking
Neuropsychologia, 2018Co-Authors: Lorenza S Colzato, Simone M. Ritter, Laura SteenbergenAbstract:Creativity is one of the most important cognitive skills in our complex and fast-changing world. Previous correlative evidence showed that gamma-aminobutyric acid (GABA) is involved in divergent but not convergent thinking. In the current study, a placebo/sham-controlled, randomized between-group design was used to test a causal relation between Vagus Nerve and creativity. We employed transcutaneous Vagus Nerve stimulation (tVNS), a novel non-invasive brain stimulation technique to stimulate afferent fibers of the Vagus Nerve and speculated to increase GABA levels, in 80 healthy young volunteers. Creative performance was assessed in terms of divergent thinking (Alternate Uses Task) and convergent thinking tasks (Remote Associates Test, Creative Problem Solving Task, Idea Selection Task). Results demonstrate active tVNS, compared to sham stimulation, enhanced divergent thinking. Bayesian analysis reported the data to be inconclusive regarding a possible effect of tVNS on convergent thinking. Therefore, our findings corroborate the idea that the Vagus Nerve is causally involved in creative performance. Even thought we did not directly measure GABA levels, our results suggest that GABA (likely to be increased in active tVNS condition) supports the ability to select among competing options in high selection demand (divergent thinking) but not in low selection demand (convergent thinking).
-
Transcutaneous Vagus Nerve stimulation (tVNS) modulates flow experience
Experimental Brain Research, 2018Co-Authors: Lorenza S Colzato, Gina Wolters, Corinna PeiferAbstract:Flow has been defined as a pleasant psychological state that people experience when completely absorbed in an activity. Previous correlative evidence showed that the vagal tone (as indexed by heart rate variability) is a reliable marker of flow. So far, it has not yet been demonstrated that the Vagus Nerve plays a causal role in flow. To explore this we used transcutaneous Vagus Nerve stimulation (tVNS), a novel non-invasive brain stimulation technique that increases activation of the locus coeruleus (LC) and norepinephrine release. A sham/placebo-controlled, randomized cross-over within-subject design was employed to infer a causal relation between the stimulated Vagus Nerve and flow as measured using the Flow Short-Scale in 32 healthy young volunteers. In both sessions, while being stimulated, participants had to rate their flow experience after having performed a task for 30 min. Active tVNS, compared to sham stimulation, decreased flow (as indexed by absorption scores). The results can be explained by the network reset theory, which assumes that high-phasic LC activity promotes a global reset of attention over exploitation of the current focus of attention, allowing rapid behavioral adaptation and resulting in decreased absorption scores. Furthermore, our findings corroborate the hypothesis that the Vagus Nerve and noradrenergic system are causally involved in flow.
Vaughan G Macefield - One of the best experts on this subject based on the ideXlab platform.
-
in vivo recordings from the human Vagus Nerve using ultrasound guided microneurography
The Journal of Physiology, 2020Co-Authors: Matteo M Ottaviani, Vaughan G Macefield, Leah Wright, Tye DawoodAbstract:Key points The Vagus Nerve is the largest cranial Nerve and innervates many structures in the neck, thorax and abdomen. Although single-unit recordings from the Vagus Nerve have been performed in experimental animals for several decades, no recordings have ever been made from the human Vagus Nerve. The Vagus Nerve is routinely stimulated clinically, yet we know little of its physiology in humans. We describe the methodology and provide preliminary results of the first intraneural single-unit recordings from the cervical Vagus in awake humans, using tungsten microelectrodes inserted into the Nerve through ultrasound guidance. Abstract Intraneural microelectrodes have been used extensively to record from single somatosensory axons supplying muscle, tendons, joints and skin, as well as to record from postganglionic sympathetic axons supplying muscle and skin, in accessible peripheral Nerves in awake humans. However, the Vagus Nerve has never been targeted, probably because of its close proximity to the carotid artery and jugular vein in the neck. Here, we report the first unitary recordings from the human cervical Vagus Nerve, obtained using ultrasound-guided insertion of tungsten microelectrodes into fascicles of the Nerve. We identified tonically-active neurones in which firing rates were inversely related to heart rate (and directly related to the cardiac interval), which we classified as putative preganglionic parasympathetic axons directed to the sinoatrial node of the heart. We also recorded from tonically-active presumed sensory axons from the airways and presumed motor axons to the larynx. This new methodology opens exciting new opportunities for studying the physiology of the human Vagus Nerve in health and disease.
Valentin A Pavlov - One of the best experts on this subject based on the ideXlab platform.
-
the Vagus Nerve and the inflammatory reflex linking immunity and metabolism
Nature Reviews Endocrinology, 2012Co-Authors: Valentin A Pavlov, Kevin J TraceyAbstract:The Vagus Nerve has an important role in regulation of metabolic homeostasis, and efferent Vagus Nerve-mediated cholinergic signalling controls immune function and proinflammatory responses via the inflammatory reflex. Dysregulation of metabolism and immune function in obesity are associated with chronic inflammation, a critical step in the pathogenesis of insulin resistance and type 2 diabetes mellitus. Cholinergic mechanisms within the inflammatory reflex have, in the past 2 years, been implicated in attenuating obesity-related inflammation and metabolic complications. This knowledge has led to the exploration of novel therapeutic approaches in the treatment of obesity-related disorders.
-
acetylcholine synthesizing t cells relay neural signals in a Vagus Nerve circuit
Science, 2011Co-Authors: Mauricio Rosasballina, Peder S Olofsson, Mahendar Ochani, Sergio I Valdesferrer, Yaakov A Levine, Colin Reardon, Michael W Tusche, Valentin A Pavlov, Ulf Andersson, Sangeeta S ChavanAbstract:Neural circuits regulate cytokine production to prevent potentially damaging inflammation. A prototypical Vagus Nerve circuit, the inflammatory reflex, inhibits tumor necrosis factor–α production in spleen by a mechanism requiring acetylcholine signaling through the α7 nicotinic acetylcholine receptor expressed on cytokine-producing macrophages. Nerve fibers in spleen lack the enzymatic machinery necessary for acetylcholine production; therefore, how does this neural circuit terminate in cholinergic signaling? We identified an acetylcholine-producing, memory phenotype T cell population in mice that is integral to the inflammatory reflex. These acetylcholine-producing T cells are required for inhibition of cytokine production by Vagus Nerve stimulation. Thus, action potentials originating in the Vagus Nerve regulate T cells, which in turn produce the neurotransmitter, acetylcholine, required to control innate immune responses.
-
transcutaneous Vagus Nerve stimulation reduces serum high mobility group box 1 levels and improves survival in murine sepsis
Critical Care Medicine, 2007Co-Authors: Jared M Huston, Mauricio Rosasballina, Mahendar Ochani, Margot Gallowitschpuerta, Kanta Ochani, Renqi Yuan, Mala Ashok, Richard S Goldstein, Valentin A PavlovAbstract:Objective: Electrical Vagus Nerve stimulation inhibits proinflammatory cytokine production and prevents shock during lethal systemic inflammation through an 7 nicotinic acetylcholine receptor (7nAChR)-dependent pathway to the spleen, termed the cholinergic anti-inflammatory pathway. Pharmacologic 7nAChR agonists inhibit production of the critical proinflammatory mediator high mobility group box 1 (HMGB1) and rescue mice from lethal polymicrobial sepsis. Here we developed a method of transcutaneous mechanical Vagus Nerve stimulation and then investigated whether this therapy can protect mice against sepsis lethality. Design: Prospective, randomized study. Setting: Institute-based research laboratory. Subjects: Male BALB/c mice. Interventions: Mice received lipopolysaccharide to induce lethal endotoxemia or underwent cecal ligation and puncture to induce polymicrobial sepsis. Mice were then randomized to receive electrical, transcutaneous, or sham Vagus Nerve stimulation and were followed for survival or euthanized at predetermined time points for cytokine analysis. Measurements and Main Results: Transcutaneous Vagus Nerve stimulation dose-dependently reduced systemic tumor necrosis factor levels during lethal endotoxemia. Treatment with transcutaneous Vagus Nerve stimulation inhibited HMGB1 levels and improved survival in mice with polymicrobial sepsis, even when administered 24 hrs after the onset of disease. Conclusions: Transcutaneous Vagus Nerve stimulation is an efficacious treatment for mice with lethal endotoxemia or polymicrobial sepsis. (Crit Care Med 2007; 35:2762‐2768)
