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Sample records for nerve magnetic stimulation

  1. Magnetic resonance based noninvasive RF nerve stimulator.

    PubMed

    Ganesh Bharadwaj, C V; Yuanjin, Zheng

    2012-01-01

    A noninvasive method of stimulating the nerve by applying radiofrequency has been presented. The design is based on the concept of magnetic resonance based power transfer. A comparison between electric field on the nerve at the frequency of 450-550 KHz with vacuum placed under a human tissue and the case where it is replaced with a resonant and non-resonant structure was analysed. Calculations were performed by using Ansoft HFSS. Power savings of 7.15% was observed when resonant structures were used, compared to vacuum. Theoretical calculation and simulation of fields were presented.

  2. Peripheral nerve magnetic stimulation: influence of tissue non-homogeneity

    PubMed Central

    Krasteva, Vessela TZ; Papazov, Sava P; Daskalov, Ivan K

    2003-01-01

    Background Peripheral nerves are situated in a highly non-homogeneous environment, including muscles, bones, blood vessels, etc. Time-varying magnetic field stimulation of the median and ulnar nerves in the carpal region is studied, with special consideration of the influence of non-homogeneities. Methods A detailed three-dimensional finite element model (FEM) of the anatomy of the wrist region was built to assess the induced currents distribution by external magnetic stimulation. The electromagnetic field distribution in the non-homogeneous domain was defined as an internal Dirichlet problem using the finite element method. The boundary conditions were obtained by analysis of the vector potential field excited by external current-driven coils. Results The results include evaluation and graphical representation of the induced current field distribution at various stimulation coil positions. Comparative study for the real non-homogeneous structure with anisotropic conductivities of the tissues and a mock homogeneous media is also presented. The possibility of achieving selective stimulation of either of the two nerves is assessed. Conclusion The model developed could be useful in theoretical prediction of the current distribution in the nerves during diagnostic stimulation and therapeutic procedures involving electromagnetic excitation. The errors in applying homogeneous domain modeling rather than real non-homogeneous biological structures are demonstrated. The practical implications of the applied approach are valid for any arbitrary weakly conductive medium. PMID:14693034

  3. Neuroprotection trek--the next generation: neuromodulation I. Techniques--deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation

    NASA Technical Reports Server (NTRS)

    Andrews, Russell J.

    2003-01-01

    Neuromodulation denotes controlled electrical stimulation of the central or peripheral nervous system. The three forms of neuromodulation described in this paper-deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation-were chosen primarily for their demonstrated or potential clinical usefulness. Deep brain stimulation is a completely implanted technique for improving movement disorders, such as Parkinson's disease, by very focal electrical stimulation of the brain-a technique that employs well-established hardware (electrode and pulse generator/battery). Vagus nerve stimulation is similar to deep brain stimulation in being well-established (for the treatment of refractory epilepsy), completely implanted, and having hardware that can be considered standard at the present time. Vagus nerve stimulation differs from deep brain stimulation, however, in that afferent stimulation of the vagus nerve results in diffuse effects on many regions throughout the brain. Although use of deep brain stimulation for applications beyond movement disorders will no doubt involve placing the stimulating electrode(s) in regions other than the thalamus, subthalamus, or globus pallidus, the use of vagus nerve stimulation for applications beyond epilepsy-for example, depression and eating disorders-is unlikely to require altering the hardware significantly (although stimulation protocols may differ). Transcranial magnetic stimulation is an example of an external or non-implanted, intermittent (at least given the current state of the hardware) stimulation technique, the clinical value of which for neuromodulation and neuroprotection remains to be determined.

  4. Basic study on the influence of inhibition induced by the magnetic stimulation on the peripheral nerve

    NASA Astrophysics Data System (ADS)

    Sato, Aya; Torii, Tetsuya; Iwahashi, Masakuni; Iramina, Keiji

    2015-05-01

    The purpose of this study is to analyze the inhibition mechanism of magnetic stimulation on motor function. A magnetic stimulator with a flat figure-eight coil was used to stimulate the peripheral nerve of the antebrachium. The intensity of magnetic stimulation was 0.8 T, and the stimulation frequency was 1 Hz. The amplitudes of the motor-evoked potentials (MEPs) at the abductor pollicis brevis muscle and first dorsal interosseous muscle were used to evaluate the effects of magnetic stimulation. The effects of magnetic stimulation were evaluated by analyzing the MEP amplitude before and after magnetic stimulation to the primary motor cortex. The results showed that MEP amplitude after magnetic stimulation compared with before magnetic stimulation decreased. Because there were individual differences in MEP amplitude induced by magnetic stimulation, the MEP amplitude after stimulation was normalized by the amplitude of each participant before stimulation. The MEP amplitude after stimulation decreased by approximately 58% (p < 0.01) on average compared with before stimulation. Previous studies suggested that magnetic stimulation to the primary motor cortex induced an increase or a decrease in MEP amplitude. Furthermore, previous studies have shown that the alteration in MEP amplitude was induced by cortical excitability based on magnetic stimulation. The results of this study showed that MEP amplitude decreased following magnetic stimulation to the peripheral nerve. We suggest that the decrease in MEP amplitude found in this study was obtained via the feedback from a peripheral nerve through an afferent nerve to the brain. This study suggests that peripheral excitement by magnetic stimulation of the peripheral nerve may control the central nervous system via afferent feedback.

  5. Peripheral nerve conduction and central motor conduction after magnetic stimulation of the brain in myotonic dystrophy.

    PubMed

    Cruz Martínez, A

    1992-06-01

    Central motor conduction time was calculated after magnetic stimulation of the brain in 15 patients with myotonic dystrophy and in 38 healthy voluntaries of the same age. Conventional electromyography and motor and sensory conduction velocities were also performed. Central motor conduction time from vertex to C8 was within the normal range in all patients whereas motor conduction velocity of the peripheral nerve and amplitude of the nerve evoked potentials were slightly reduced in 3 and 2 cases respectively, supporting peripheral nerve involvement in some subjects. Our results suggest that the reported central nervous system involvement in myotonic dystrophy, including the nonspecific white matter lesions showed by magnetic resonance imaging, would not affect the conduction of the corticospinal tracts. Magnetic stimulation on the motor cortex is a painless method to study the central nervous system and apports a satisfactory approximation to central motor pathways conduction.

  6. Noninvasive techniques for probing neurocircuitry and treating illness: vagus nerve stimulation (VNS), transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS)

    PubMed Central

    George, Mark S; Aston-Jones, Gary

    2010-01-01

    Although the preceding chapters discuss much of the new knowledge of neurocircuitry of neuropsychiatric diseases, and an invasive approach to treatment, this chapter describes and reviews the noninvasive methods of testing circuit-based theories and treating neuropsychiatric diseases that do not involve implanting electrodes into the brain or on its surface. These techniques are transcranial magnetic stimulation, vagus nerve stimulation, and transcranial direct current stimulation. Two of these approaches have FDA approval as therapies. PMID:19693003

  7. Reference values and clinical application of magnetic peripheral nerve stimulation in cats.

    PubMed

    Van Soens, Iris; Struys, Michel M R F; Bhatti, Sofie F M; Van Ham, Luc M L

    2012-07-01

    Magnetic stimulation of radial (RN) and sciatic (SN) nerves was performed bilaterally in 40 healthy cats. Reference values for onset latency and peak-to-peak amplitude of magnetic motor evoked potentials (MMEPs) were obtained and compared with values of electric motor evoked potentials (EMEPs) in 10/40 cats. Onset latencies and peak-to-peak amplitudes of the MMEPs of three cats with polyneuropathy (PNP) were compared to the reference values. Magnetic motor evoked responses were easily recorded in all normal cats. Significant differences were found in onset latencies between MMEPs and EMEPs, but peak-to-peak amplitudes were equal. The MMEPs of three cats with PNP can be seen as outliers in comparison to the reference values. MMEPs from the RN and SN were easily obtained and reproducible in normal cats. The technique could represent a useful adjunct in the assessment of peripheral nerve disorders. PMID:22070914

  8. Peripheral nerve stimulation: definition.

    PubMed

    Abejón, David; Pérez-Cajaraville, Juan

    2011-01-01

    Recently, there has been a tremendous evolution in the field of neurostimulation, both from the technological point of view and from development of the new and different indications. In some areas, such as peripheral nerve stimulation, there has been a boom in recent years due to the variations in the surgical technique and the improved results documented by in multiple published papers. All this makes imperative the need to classify and define the different types of stimulation that are used today. The confusion arises when attempting to describe peripheral nerve stimulation and subcutaneous stimulation. Peripheral nerve stimulation, in its pure definition, involves implanting a lead on a nerve, with the aim to produce paresthesia along the entire trajectory of the stimulated nerve.

  9. Electromechanical Nerve Stimulator

    NASA Technical Reports Server (NTRS)

    Tcheng, Ping; Supplee, Frank H., Jr.; Prass, Richard L.

    1993-01-01

    Nerve stimulator applies and/or measures precisely controlled force and/or displacement to nerve so response of nerve measured. Consists of three major components connected in tandem: miniature probe with spherical tip; transducer; and actuator. Probe applies force to nerve, transducer measures force and sends feedback signal to control circuitry, and actuator positions force transducer and probe. Separate box houses control circuits and panel. Operator uses panel to select operating mode and parameters. Stimulator used in research to characterize behavior of nerve under various conditions of temperature, anesthesia, ventilation, and prior damage to nerve. Also used clinically to assess damage to nerve from disease or accident and to monitor response of nerve during surgery.

  10. Vagus Nerve Stimulation

    PubMed Central

    Howland, Robert H.

    2014-01-01

    The vagus nerve is a major component of the autonomic nervous system, has an important role in the regulation of metabolic homeostasis, and plays a key role in the neuroendocrine-immune axis to maintain homeostasis through its afferent and efferent pathways. Vagus nerve stimulation (VNS) refers to any technique that stimulates the vagus nerve, including manual or electrical stimulation. Left cervical VNS is an approved therapy for refractory epilepsy and for treatment resistant depression. Right cervical VNS is effective for treating heart failure in preclinical studies and a phase II clinical trial. The effectiveness of various forms of non-invasive transcutaneous VNS for epilepsy, depression, primary headaches, and other conditions has not been investigated beyond small pilot studies. The relationship between depression, inflammation, metabolic syndrome, and heart disease might be mediated by the vagus nerve. VNS deserves further study for its potentially favorable effects on cardiovascular, cerebrovascular, metabolic, and other physiological biomarkers associated with depression morbidity and mortality. PMID:24834378

  11. Sacral nerve stimulation.

    PubMed

    Matzel, K E; Stadelmaier, U; Besendörfer, M

    2004-01-01

    The current concept of recruiting residual function of an inadequate pelvic organ by electrostimulation involves stimulation of the sacral spinal nerves at the level of the sacral canal. The rationale for applying SNS to fecal incontinence was based on clinical observations of its effect on bowel habits and anorectal continence function in urologic patients (increased anorectal angulation and anal canal closure pressure) and on anatomic considerations: dissection demonstrated a dual peripheral nerve supply of the striated pelvic floor muscles that govern these functions. Because the sacral spinal nerve site is the most distal common location of this dual nerve supply, stimulating here can elicit both functions. Since the first application of SNS in fecal incontinence in 1994, this technique has been improved, the patient selection process modified, and the spectrum of indications expanded. At present SNS has been applied in more than 1300 patients with fecal incontinence limited.

  12. The effect of single-pulse transcranial magnetic stimulation and peripheral nerve stimulation on complexity of EMG signal: fractal analysis.

    PubMed

    Cukic, M; Oommen, J; Mutavdzic, D; Jorgovanovic, N; Ljubisavljevic, M

    2013-07-01

    The aim of this study was to examine whether single-pulse transcranial magnetic stimulation (spTMS) affects the pattern of corticospinal activity once voluntary drive has been restored after spTMS-induced EMG silence. We used fractal dimension (FD) to explore the 'complexity' of the electromyography (EMG) signal, and median frequency of the spectra (MDF) to examine changes in EMG spectral characteristics. FD and MDF of the raw EMG epochs immediately before were compared with those obtained from epochs after the EMG silence. Changes in FD and MDF after spTMS were examined with three levels of muscle contraction corresponding to weak (20-40%), moderate (40-60%) and strong (60-80% of maximal voluntary contraction) and three intensities of stimulation set at 10, 20 and 30% above the resting motor threshold. FD was calculated using the Higuchi fractal dimension algorithm. Finally, to discern the origin of FD changes between the CNS and muscle, we compared the effects of spTMS with the effects of peripheral nerve stimulation (PNS) on FD and MDF. The results show that spTMS induced significant decrease in both FD and MDF of EMG signal after stimulation. PNS did not have any significant effects on FD nor MDF. Changes in TMS intensity did not have any significant effect on FD or MDF after stimulation nor had the strength of muscle contraction. However, increase in contraction strength decreased FD before stimulation but only between weak and moderate contraction. The results suggest that the effects of spTMS on corticospinal activity, underlying voluntary motor output, outlast the TMS stimulus. It appears that the complexity of the EMG signal is reduced after spTMS, suggesting that TMS alters the dynamics of the ongoing corticospinal activity most likely temporarily synchronizing the neural network activity. Further studies are needed to confirm whether observed changes after TMS occur at the cortical level. PMID:23652725

  13. Magnetoneurographic registration of propagating magnetic fields in the lumbar spine after stimulation of the posterior tibial nerve

    NASA Astrophysics Data System (ADS)

    Klein, Anita; van Leeuwen, Peter; Hoormann, Jörg; Grönemeyer, Dietrich

    2006-06-01

    Stimulation of the posterior tibial nerve has been associated with different somatosensory evoked potentials (SEP) recorded along the spine and thorax. The aim of this study was to register and describe the magnetic fields corresponding to different components of spinal SEP after stimulation of tibial nerves. In nine healthy subjects, right and left posterior tibial nerves were transcutaneously electrostimulated at the ankles. Neuromagnetic fields were registered over a circular 800 cm2 area of the lumbosacral spine using a 61-channel biomagnetometer. Magnetic field maps were constructed and examined visually for dipolar patterns. Equivalent current dipoles (ECD) were calculated for each somatosensory evoked field (SEF) using a least-squares fit in a spherical model. In seven subjects dipolar SEF were detected over the lower back at two separate latencies and locations and propagating ECD could be localized. Both the first and second components found agreed anatomically and functionally with respect to propagation in the underlying nerve fibers. It was possible to record and identify SEF which correspond to the SEP described in the literature. Dipole localization based on an equivalent current dipole model allowed a basic evaluation of the plausibility of the measurements with respect to the processes being examined.

  14. Magnetically induced vagal nerve stimulation and food intake and body mass in growing rats.

    PubMed

    Ziomber, Agata; Zaraska, Wiesław; Bugajski, Andrzej; Thor, Piotr J

    2005-01-01

    Electrostimulation of vagal nerve (VNS) by microchip (MC) with magnetic field energy supply may "mimic" the physiological output associated with gastric mechanoreceptors activation by food and lead to decrease in food intake and subsequently decrease in weight gain. Vago-vagal reflexes in growing animals seems to be mainly responsible for meal size regulation and other compensatory (hormonal or neural) mechanisms prevent from decrease in body mass.

  15. Repetitive magnetic stimulation affects the microenvironment of nerve regeneration and evoked potentials after spinal cord injury

    PubMed Central

    Jiang, Jin-lan; Guo, Xu-dong; Zhang, Shu-quan; Wang, Xin-gang; Wu, Shi-feng

    2016-01-01

    Repetitive magnetic stimulation has been shown to alter local blood flow of the brain, excite the corticospinal tract and muscle, and induce motor function recovery. We established a rat model of acute spinal cord injury using the modified Allen's method. After 4 hours of injury, rat models received repetitive magnetic stimulation, with a stimulus intensity of 35% maximum output intensity, 5-Hz frequency, 5 seconds for each sequence, and an interval of 2 minutes. This was repeated for a total of 10 sequences, once a day, 5 days in a week, for 2 consecutive weeks. After repetitive magnetic stimulation, the number of apoptotic cells decreased, matrix metalloproteinase 9/2 gene and protein expression decreased, nestin expression increased, somatosensory and motor-evoked potentials recovered, and motor function recovered in the injured spinal cord. These findings confirm that repetitive magnetic stimulation of the spinal cord improved the microenvironment of neural regeneration, reduced neuronal apoptosis, and induced neuroprotective and repair effects on the injured spinal cord. PMID:27335567

  16. Noninvasive and painless magnetic stimulation of nerves improved brain motor function and mobility in a cerebral palsy case.

    PubMed

    Flamand, Véronique H; Schneider, Cyril

    2014-10-01

    Motor deficits in cerebral palsy disturb functional independence. This study tested whether noninvasive and painless repetitive peripheral magnetic stimulation could improve motor function in a 7-year-old boy with spastic hemiparetic cerebral palsy. Stimulation was applied over different nerves of the lower limbs for 5 sessions. We measured the concurrent aftereffects of this intervention on ankle motor control, gait (walking velocity, stride length, cadence, cycle duration), and function of brain motor pathways. We observed a decrease of ankle plantar flexors resistance to stretch, an increase of active dorsiflexion range of movement, and improvements of corticospinal control of ankle dorsiflexors. Joint mobility changes were still present 15 days after the end of stimulation, when all gait parameters were also improved. Resistance to stretch was still lower than prestimulation values 45 days after the end of stimulation. This case illustrates the sustained effects of repetitive peripheral magnetic stimulation on brain plasticity, motor function, and gait. It suggests a potential impact for physical rehabilitation in cerebral palsy.

  17. Effect of high-frequency repetitive transcranial magnetic stimulation on motor cortical excitability and sensory nerve conduction velocity in subacute-stage incomplete spinal cord injury patients.

    PubMed

    Cha, Hyun Gyu; Ji, Sang-Goo; Kim, Myoung-Kwon

    2016-07-01

    [Purpose] The aim of the present study was to determine whether repetitive transcranial magnetic stimulation can improve sensory recovery of the lower extremities in subacute-stage spinal cord injury patients. [Subjects and Methods] This study was conducted on 20 subjects with diagnosed paraplegia due to spinal cord injury. These 20 subjects were allocated to an experimental group of 10 subjects that underwent active repetitive transcranial magnetic stimulation or to a control group of 10 subjects that underwent sham repetitive transcranial magnetic stimulation. The SCI patients in the experimental group underwent active repetitive transcranial magnetic stimulation and conventional rehabilitation therapy, whereas the spinal cord injury patients in the control group underwent sham repetitive transcranial magnetic stimulation and conventional rehabilitation therapy. Participants in both groups received therapy five days per week for six-weeks. Latency, amplitude, and sensory nerve conduction velocity were assessed before and after the six week therapy period. [Results] A significant intergroup difference was observed for posttreatment velocity gains, but no significant intergroup difference was observed for amplitude or latency. [Conclusion] repetitive transcranial magnetic stimulation may be improve sensory recovery of the lower extremities in subacute-stage spinal cord injury patients. PMID:27512251

  18. Effect of high-frequency repetitive transcranial magnetic stimulation on motor cortical excitability and sensory nerve conduction velocity in subacute-stage incomplete spinal cord injury patients

    PubMed Central

    Cha, Hyun Gyu; Ji, Sang-Goo; Kim, Myoung-Kwon

    2016-01-01

    [Purpose] The aim of the present study was to determine whether repetitive transcranial magnetic stimulation can improve sensory recovery of the lower extremities in subacute-stage spinal cord injury patients. [Subjects and Methods] This study was conducted on 20 subjects with diagnosed paraplegia due to spinal cord injury. These 20 subjects were allocated to an experimental group of 10 subjects that underwent active repetitive transcranial magnetic stimulation or to a control group of 10 subjects that underwent sham repetitive transcranial magnetic stimulation. The SCI patients in the experimental group underwent active repetitive transcranial magnetic stimulation and conventional rehabilitation therapy, whereas the spinal cord injury patients in the control group underwent sham repetitive transcranial magnetic stimulation and conventional rehabilitation therapy. Participants in both groups received therapy five days per week for six-weeks. Latency, amplitude, and sensory nerve conduction velocity were assessed before and after the six week therapy period. [Results] A significant intergroup difference was observed for posttreatment velocity gains, but no significant intergroup difference was observed for amplitude or latency. [Conclusion] repetitive transcranial magnetic stimulation may be improve sensory recovery of the lower extremities in subacute-stage spinal cord injury patients. PMID:27512251

  19. Technology for Peripheral Nerve Stimulation.

    PubMed

    Parker, John L; Cameron, Tracy

    2015-01-01

    Peripheral nerve stimulation (PNS) has been in use for over 50 years to treat patients suffering from chronic pain who have failed conservative treatments. Despite this long history, the devices being used have changed very little. In fact, current PNS technology was developed specifically for spinal cord stimulation. The use of technology developed for other applications in PNS has led to an unnecessary number of device complications and the limited adoption of this promising therapy. The following chapter provides an overview of PNS technology throughout the years, outlining both the benefits and limitations. We will briefly explore the electrophysiology of PNS stimulation, with an emphasis on technology and indication-specific devices. Finally, design and technical requirements of an ideal PNS device will be discussed.

  20. Spiral scan peripheral nerve stimulation.

    PubMed

    King, K F; Schaefer, D J

    2000-07-01

    Time-varying magnetic fields induce electric fields that can cause physiological stimulation. Stimulation has been empirically characterized as a function of dB/dt and duration based on experiments using trapezoidal and sinusoidal gradient waveforms with constant ramp time, amplitude, and direction. For two-dimensional (2D) spiral scans, the readout gradient waveforms are frequency- and amplitude-modulated sinusoids on two orthogonal axes in quadrature. The readout gradient waveform therefore rotates with amplitude and angular velocity that are generally not constant. It does not automatically follow that spiral stimulation thresholds can be predicted using available stimulation models. We scanned 18 normal volunteers with a 2D spiral scan and measured global thresholds for axial, sagittal, and coronal planes. We concluded that the stimulation model evaluated accurately predicts slew rate-limited spiral mean stimulation thresholds, if the effective ramp time is chosen to be the half-period at the end of the spiral readout.

  1. Central motor conduction time by magnetic stimulation of the cortex and peripheral nerve conduction follow-up studies in Friedreich's ataxia.

    PubMed

    Cruz-Martínez, A; Palau, F

    1997-12-01

    A follow-up clinical study, peripheral motor and sensory nerve conduction velocities and central motor conduction by magnetic stimulation of the cortex were performed in 13 patients with classical Friedreich's ataxia (FA) phenotype, for a period of 9-12 years. Clinical worsening was unrelated to peripheral nerve abnormalities. The amplitude of the nerve action potentials and delayed conduction velocity remained unchanged for several years. Central motor conduction times were abnormal in all patients. Clinical conditions worsened significantly between successive examinations with significant increments in threshold and significant decrement of the amplitude of motor evoked potentials. The results are consistent with progressive pyramidal and cerebellar pathways involvement as the cause of clinical worsening in FA.

  2. Somatosensory evoked potentials can be recorded on the midline of the skull with subdermal electrodes in non-sedated rats elicited by magnetic stimulation of the tibial nerve.

    PubMed

    Zhang, Shu-Xin; Huang, Fengfa; Gates, Mary; Holmberg, Eric G

    2012-07-15

    Somatosensory evoked potentials (SSEPs) are a sensitive quantitative measure of conduction in somatosensory pathways of the central nervous system and are increasingly used in both clinical trials and animal experiments. SSEPs can be recorded in non-sedated rodents by magnetic stimulation (MS) of peripheral nerves. To overcome some disadvantages caused by using anesthesia and implanted recording electrodes, we used subdermal needle electrodes located on the midline of the skull to successfully record SSEPs in non-sedated rats, elicited by stimulating the tibial nerve with a magnetic stimulator. The wave form contains a typical P1 peak and N1 peak. Although there is a variation of P1 latency, N1 latency, and P1-N1 amplitude between right side and left side, it was not statistically significant. In addition, there is a significantly positive relationship between P1-N1 amplitude and MS strength, suggesting that the increase in magnetic stimulating strength resulted in the increase in P1-N1 amplitude. Results in the present study demonstrate that our modified method is a reliable and feasible paradigm for recording SSEPs in non-sedated rats. PMID:22579876

  3. [Electrical nerve stimulation for plexus and nerve blocks].

    PubMed

    Birnbaum, J; Klotz, E; Bogusch, G; Volk, T

    2007-11-01

    Despite the increasing use of ultrasound, electrical nerve stimulation is commonly used as the standard for both plexus and peripheral nerve blocks. Several recent randomized trials have contributed to a better understanding of physiological and clinical correlations. Traditionally used currents and impulse widths are better defined in relation to the distance between needle tip and nerves. Commercially available devices enable transcutaneous nerve stimulation and provide new opportunities for the detection of puncture sites and for training. The electrically ideal position of the needle usually is defined by motor responses which can not be interpreted without profound anatomical knowledge. For instance, interscalene blocks can be successful even after motor responses of deltoid or pectoral muscles. Infraclavicular blocks should be aimed at stimulation of the posterior fascicle (extension). In contrast to multiple single nerve blocks, axillary single-shot blocks more commonly result in incomplete anaesthesia. Blockade of the femoral nerve can be performed without any nerve stimulation if the fascia iliaca block is used. Independently of the various approaches to the sciatic nerve, inversion and plantar flexion are the best options for single-shot blocks. Further clinical trials are needed to define the advantages of stimulating catheters in continuous nerve blocks.

  4. Cardiovascular effects of afferent renal nerve stimulation.

    PubMed

    Stella, A; Weaver, L; Golin, R; Genovesi, S; Zanchetti, A

    1987-01-01

    Electrical stimulation of afferent renal nerves elicits an increase in arterial pressure and heart rate. The hypertensive response is presumably due to the widespread activation of the sympathetic nervous system leading to peripheral vasoconstriction. Interestingly, the kidney does not appear involved in this reflex excitatory response to afferent renal nerve stimulation since changes in vascular conductances and excretory functions are equal in both the innervated and denervated kidney, and secondary to changes in renal perfusion pressure. In addition, no changes in renin release from either kidneys are observed during afferent renal nerve stimulation. It is likely that the electrical stimulation of afferent renal nerves activates other reflexes exerting an inhibitory influence on efferent renal nerve activity. Indeed, neural renorenal reflexes which tonically inhibit renal functions have clearly been demonstrated. Furthermore, preferential inhibition of efferent renal nerve activity by cardiopulmonary and sinoaortic receptors has recently been shown during activation of other visceral afferents.

  5. Optical nerve stimulation for a vestibular prosthesis

    NASA Astrophysics Data System (ADS)

    Harris, David M.; Bierer, Steven M.; Wells, Jonathon D.; Phillips, James O.

    2009-02-01

    Infrared Nerve Stimulation (INS) offers several advantages over electrical stimulation, including more precise spatial selectivity and improved surgical access. In this study, INS and electrical stimulation were compared in their ability to activate the vestibular branch of the VIIIth nerve, as a potential way to treat balance disorders. The superior and lateral canals of the vestibular system of Guinea pigs were identified and approached with the aid of precise 3-D reconstructions. A monopolar platinum stimulating electrode was positioned near the ampullae of the canals, and biphasic current pulses were used to stimulate vestibular evoked potentials and eye movements. Thresholds and input/output functions were measured for various stimulus conditions. A short pulsed diode laser (Capella, Lockheed Martin-Aculight, Inc., Bothell WA) was placed in the same anatomical position and various stimulus conditions were evaluated in their ability to evoke similar potentials and eye movements.

  6. Transcutaneous Electrical Nerve Stimulation: Research Update.

    ERIC Educational Resources Information Center

    Johns, Florene Carnicelli

    Currently, research is being performed in the area of nonsurgical and nonchemical means for influencing the body's threshold for pain. Today, transcutaneous electrical nerve stimulation (TENS) is being widely used for this purpose. Application of this treatment can be confusing, however, because determining such things as selection of the proper…

  7. Vagus nerve stimulation: predictors of seizure freedom

    PubMed Central

    Janszky, J; Hoppe, M; Behne, F; Tuxhorn, I; Pannek, H; Ebner, A

    2005-01-01

    Objectives: To identify predictive factors for the seizure-free outcome of vagus nerve stimulation (VNS). Methods: All 47 patients who had undergone VNS implantation at one centre and had at least one year of follow up were studied. They underwent complete presurgical evaluation including detailed clinical history, magnetic resonance imaging, and long term video-EEG with ictal and interictal recordings. After implantation, adjustment of stimulation parameters and concomitant antiepileptic drugs were at the discretion of the treating physician. Results: Mean (SD) age of the patients was 22.7 (11.6) years (range 7 to 53). Six patients (13%) became seizure-free after the VNS implantation. Only two variables showed a significant association with the seizure-free outcome: absence of bilateral interictal epileptiform discharges (IED) and presence of malformation of cortical development (MCD). Epilepsy duration showed a non-significant trend towards a negative association with outcome. By logistic regression analysis, only absence of bilateral IED correlated independently with successful VNS treatment (p<0.01, odds ratio = 29.2 (95% confidence interval, 2.4 to 353)). Bilateral IED (independent or bilateral synchronous) was found in one of six seizure-free patients and in 33 of 41 non-seizure-free patients. When bilateral IED were absent, the sensitivity for seizure-free outcome was 0.83 (0.44 to 0.97), and the specificity was 0.80 (0.66 to 0.90). Conclusions: Bilateral IED was independently associated with the outcome of VNS. These results are preliminary because they were based on a small patient population. They may facilitate prospective VNS studies enrolling larger numbers of patients to confirm the results. PMID:15716532

  8. 21 CFR 874.1820 - Surgical nerve stimulator/locator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1820 Surgical nerve stimulator/locator. (a) Identification. A surgical nerve stimulator/locator is a device that is intended...

  9. 21 CFR 874.1820 - Surgical nerve stimulator/locator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1820 Surgical nerve stimulator/locator. (a) Identification. A surgical nerve stimulator/locator is a device that is intended...

  10. Vagal Nerve Stimulation Therapy: What Is Being Stimulated?

    PubMed Central

    Kember, Guy; Ardell, Jeffrey L.; Armour, John A.; Zamir, Mair

    2014-01-01

    Vagal nerve stimulation in cardiac therapy involves delivering electrical current to the vagal sympathetic complex in patients experiencing heart failure. The therapy has shown promise but the mechanisms by which any benefit accrues is not understood. In this paper we model the response to increased levels of stimulation of individual components of the vagal sympathetic complex as a differential activation of each component in the control of heart rate. The model provides insight beyond what is available in the animal experiment in as much as allowing the simultaneous assessment of neuronal activity throughout the cardiac neural axis. The results indicate that there is sensitivity of the neural network to low level subthreshold stimulation. This leads us to propose that the chronic effects of vagal nerve stimulation therapy lie within the indirect pathways that target intrinsic cardiac local circuit neurons because they have the capacity for plasticity. PMID:25479368

  11. Comparison of quadriceps inactivation between nerve and muscle stimulation.

    PubMed

    Place, Nicolas; Casartelli, Nicola; Glatthorn, Julia F; Maffiuletti, Nicola A

    2010-12-01

    We evaluated the use of direct muscle stimulation for quantifying quadriceps inactivation at different contraction levels as opposed to conventional twitch interpolation using nerve stimulation. Fourteen healthy volunteers were tested. Paired stimuli were delivered to the femoral nerve or to the quadriceps muscle belly during voluntary contractions ranging from 20% to 100% of maximum, and the amplitude of the superimposed doublet was quantified to investigate inactivation. Superimposed doublet for muscle and nerve stimulation, respectively between the range of 60% to 100% of maximum (e.g., at 100%, muscle stimulation was 14 ± 5 Nm and nerve stimulation was 15 ± 6 Nm). Despite higher current doses, muscle stimulation was associated with less discomfort than nerve stimulation (P < 0.05). Collectively, our data suggest that direct muscle stimulation could be used to assess quadriceps inactivation at maximal and quasi-maximal contraction levels as a valid alternative to motor nerve stimulation.

  12. Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea.

    PubMed

    Mwenge, Gimbada B; Rombaux, Philippe; Lengele, Benoit; Rodenstein, Daniel

    2015-01-01

    Obstructive sleep apnea (OSA) is a very frequent affliction that affects about 1-5% of the adult population in its severe form. Continuous positive airway pressure (CPAP) is the most commonly used treatment and is highly effective, but its use is limited by low long-term adherence rates and overall poor acceptance among the patients. Therefore, there is a need for developing alternative approaches to OSA treatment, including a more 'natural' concept of maintaining an open airway through neuromodulation. Here we review the concept, scientific rationale, and technical details of hypoglossal nerve stimulation. We also review results of published clinical studies with several hypoglossal stimulation devices that are being investigated today. Hypoglossal nerve stimulation appears to be a very promising treatment for patients with moderate-to-severe OSA. If its efficacy is confirmed, it will probably be complementary with CPAP therapy and initially aimed at patients unable or unwilling to use CPAP. Once it becomes a standard therapy, its advantages might prove sufficient to challenge CPAP as the first-line therapy.

  13. Short-interval intracortical inhibition is modulated by high-frequency peripheral mixed nerve stimulation.

    PubMed

    Murakami, Takenobu; Sakuma, Kenji; Nomura, Takashi; Nakashima, Kenji

    2007-06-01

    Cortical excitability can be modulated by manipulation of afferent input. We investigated the influence of peripheral mixed nerve stimulation on the excitability of the motor cortex. Motor evoked potentials (MEPs), short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) in the right abductor pollicis brevis (APB), extensor carpi radialis (ECR) and first dorsal interosseous (FDI) muscles were evaluated using paired-pulse transcranial magnetic stimulation (TMS) before and after high-frequency peripheral mixed nerve stimulation (150 Hz, 30 min) over the right median nerve at the wrist. The MEP amplitude and SICI of the APB muscle decreased transiently 0-10 min after the intervention, whereas the ICF did not change. High-frequency peripheral mixed nerve stimulation reduced the excitability of the motor cortex. The decrement in the SICI, which reflects the function of GABA(A)ergic inhibitory interneurons, might compensate for the reduced motor cortical excitability after high-frequency peripheral mixed nerve stimulation.

  14. Non-invasive electrical and magnetic stimulation of the brain, spinal cord, roots and peripheral nerves: Basic principles and procedures for routine clinical and research application. An updated report from an I.F.C.N. Committee.

    PubMed

    Rossini, P M; Burke, D; Chen, R; Cohen, L G; Daskalakis, Z; Di Iorio, R; Di Lazzaro, V; Ferreri, F; Fitzgerald, P B; George, M S; Hallett, M; Lefaucheur, J P; Langguth, B; Matsumoto, H; Miniussi, C; Nitsche, M A; Pascual-Leone, A; Paulus, W; Rossi, S; Rothwell, J C; Siebner, H R; Ugawa, Y; Walsh, V; Ziemann, U

    2015-06-01

    These guidelines provide an up-date of previous IFCN report on "Non-invasive electrical and magnetic stimulation of the brain, spinal cord and roots: basic principles and procedures for routine clinical application" (Rossini et al., 1994). A new Committee, composed of international experts, some of whom were in the panel of the 1994 "Report", was selected to produce a current state-of-the-art review of non-invasive stimulation both for clinical application and research in neuroscience. Since 1994, the international scientific community has seen a rapid increase in non-invasive brain stimulation in studying cognition, brain-behavior relationship and pathophysiology of various neurologic and psychiatric disorders. New paradigms of stimulation and new techniques have been developed. Furthermore, a large number of studies and clinical trials have demonstrated potential therapeutic applications of non-invasive brain stimulation, especially for TMS. Recent guidelines can be found in the literature covering specific aspects of non-invasive brain stimulation, such as safety (Rossi et al., 2009), methodology (Groppa et al., 2012) and therapeutic applications (Lefaucheur et al., 2014). This up-dated review covers theoretical, physiological and practical aspects of non-invasive stimulation of brain, spinal cord, nerve roots and peripheral nerves in the light of more updated knowledge, and include some recent extensions and developments. PMID:25797650

  15. Non-invasive electrical and magnetic stimulation of the brain, spinal cord, roots and peripheral nerves: Basic principles and procedures for routine clinical and research application. An updated report from an I.F.C.N. Committee.

    PubMed

    Rossini, P M; Burke, D; Chen, R; Cohen, L G; Daskalakis, Z; Di Iorio, R; Di Lazzaro, V; Ferreri, F; Fitzgerald, P B; George, M S; Hallett, M; Lefaucheur, J P; Langguth, B; Matsumoto, H; Miniussi, C; Nitsche, M A; Pascual-Leone, A; Paulus, W; Rossi, S; Rothwell, J C; Siebner, H R; Ugawa, Y; Walsh, V; Ziemann, U

    2015-06-01

    These guidelines provide an up-date of previous IFCN report on "Non-invasive electrical and magnetic stimulation of the brain, spinal cord and roots: basic principles and procedures for routine clinical application" (Rossini et al., 1994). A new Committee, composed of international experts, some of whom were in the panel of the 1994 "Report", was selected to produce a current state-of-the-art review of non-invasive stimulation both for clinical application and research in neuroscience. Since 1994, the international scientific community has seen a rapid increase in non-invasive brain stimulation in studying cognition, brain-behavior relationship and pathophysiology of various neurologic and psychiatric disorders. New paradigms of stimulation and new techniques have been developed. Furthermore, a large number of studies and clinical trials have demonstrated potential therapeutic applications of non-invasive brain stimulation, especially for TMS. Recent guidelines can be found in the literature covering specific aspects of non-invasive brain stimulation, such as safety (Rossi et al., 2009), methodology (Groppa et al., 2012) and therapeutic applications (Lefaucheur et al., 2014). This up-dated review covers theoretical, physiological and practical aspects of non-invasive stimulation of brain, spinal cord, nerve roots and peripheral nerves in the light of more updated knowledge, and include some recent extensions and developments.

  16. Regulation of Peripheral Nerve Stimulation Technology.

    PubMed

    Birk, Daniel M; Yin, Dali; Slavin, Konstantin V

    2015-01-01

    The number of peripheral nerve stimulation (PNS) indications, targets, and devices is expanding, yet the development of the technology has been slow because many devices used for PNS do not have formal regulatory approval. Manufacturers have not sought Food and Drug Administration (FDA) approval for PNS devices because of a perceived lack of interest amongst practitioners and patients. Without FDA approval, companies cannot invest in marketing to educate the implanters and the patients about the benefits of PNS in the treatment of chronic pain. Violation of this has resulted in governmental investigation and prosecution. Most of the PNS devices currently used to treat chronic pain are FDA approved for epidural spinal cord stimulation. Many of the complications seen in PNS surgery can be attributed to the lack of purpose-built hardware with FDA approval. Despite the lack of regulatory approval, there are insurance companies that approve PNS procedures when deemed medically necessary. As the targets and indications for PNS continue to expand, there will be an even greater need for customized technological solutions. It is up to the medical device industry to invest in the design and marketing of PNS technology and seek out FDA approval. Market forces will continue to push PNS into the mainstream and physicians will increasingly have the choice to implant devices specifically designed and approved to treat chronic peripheral nerve pain. PMID:26394389

  17. Investigation of assumptions underlying current safety guidelines on EM-induced nerve stimulation

    NASA Astrophysics Data System (ADS)

    Neufeld, Esra; Vogiatzis Oikonomidis, Ioannis; Iacono, Maria Ida; Angelone, Leonardo M.; Kainz, Wolfgang; Kuster, Niels

    2016-06-01

    An intricate network of a variety of nerves is embedded within the complex anatomy of the human body. Although nerves are shielded from unwanted excitation, they can still be stimulated by external electromagnetic sources that induce strongly non-uniform field distributions. Current exposure safety standards designed to limit unwanted nerve stimulation are based on a series of explicit and implicit assumptions and simplifications. This paper demonstrates the applicability of functionalized anatomical phantoms with integrated coupled electromagnetic and neuronal dynamics solvers for investigating the impact of magnetic resonance exposure on nerve excitation within the full complexity of the human anatomy. The impact of neuronal dynamics models, temperature and local hot-spots, nerve trajectory and potential smoothing, anatomical inhomogeneity, and pulse duration on nerve stimulation was evaluated. As a result, multiple assumptions underlying current safety standards are questioned. It is demonstrated that coupled EM-neuronal dynamics modeling involving realistic anatomies is valuable to establish conservative safety criteria.

  18. Electroactive biocompatible materials for nerve cell stimulation

    NASA Astrophysics Data System (ADS)

    Yang, Mei; Liang, Youlong; Gui, Qingyuan; Chen, Jun; Liu, Yong

    2015-04-01

    In the past decades, great efforts have been developed for neurobiologists and neurologists to restore nervous system functions. Recently much attention has been paid to electrical stimulation (ES) of the nervous system as a potential way to repair it. Various conductive biocompatible materials with good electrical conductivity, biocompatibility, and long-term ES or electrical stability have been developed as the substrates for ES. In this review, we summarized different types of materials developed in the purpose for ES of nervous system, including conducting polymers, carbon nanomaterials and composites from conducting polymer/carbon nanomaterials. The present review will give our perspective on the future research directions for further investigation on development of ES particularly on the nerve system.

  19. Vagus nerve stimulation: indications and limitations.

    PubMed

    Ansari, S; Chaudhri, K; Al Moutaery, K A

    2007-01-01

    Vagus nerve stimulation (VNS) is an established treatment for selected patients with medically refractory seizures. Recent studies suggest that VNS could be potentially useful in the treatment of resistant depressive disorder. Although a surgical procedure is required in order to implant the VNS device, the possibility of a long-term benefit largely free of severe side effects could give VNS a privileged place in the management of resistant depression. In addition, VNS appears to affect pain perception in depressed adults; a possible role of VNS in the treatment of severe refractory headache, intractable chronic migraine and cluster headache has also been suggested. VNS is currently investigated in clinical studies, as a potential treatment for essential tremor, cognitive deficits in Alzheimer's disease, anxiety disorders, and bulimia. Finally, other studies explore the potential use of VNS in the treatment of resistant obesity, addictions, sleep disorders, narcolepsy, coma and memory and learning deficits.

  20. Bladder emptying by intermittent electrical stimulation of the pudendal nerve

    NASA Astrophysics Data System (ADS)

    Boggs, Joseph W.; Wenzel, Brian J.; Gustafson, Kenneth J.; Grill, Warren M.

    2006-03-01

    Persons with a suprasacral spinal cord injury cannot empty their bladder voluntarily. Bladder emptying can be restored by intermittent electrical stimulation of the sacral nerve roots (SR) to cause bladder contraction. However, this therapy requires sensory nerve transection to prevent dyssynergic contraction of the external urethral sphincter (EUS). Stimulation of the compound pudendal nerve trunk (PN) activates spinal micturition circuitry, leading to a reflex bladder contraction without a reflex EUS contraction. The present study determined if PN stimulation could produce bladder emptying without nerve transection in cats anesthetized with α-chloralose. With all nerves intact, intermittent PN stimulation emptied the bladder (64 ± 14% of initial volume, n = 37 across six cats) more effectively than either distention-evoked micturition (40 ± 19%, p < 0.001, n = 27 across six cats) or bilateral intermittent SR stimulation (25 ± 23%, p < 0.005, n = 4 across two cats). After bilateral transection of the nerves innervating the urethral sphincter, intermittent SR stimulation voided 79 ± 17% (n = 12 across three cats), comparable to clinical results obtained with SR stimulation. Voiding via intermittent PN stimulation did not increase after neurotomy (p > 0.10), indicating that PN stimulation was not limited by bladder-sphincter dyssynergia. Intermittent PN stimulation holds promise for restoring bladder emptying following spinal injury without requiring nerve transection.

  1. Neuroprotective effects of vagus nerve stimulation on traumatic brain injury

    PubMed Central

    Zhou, Long; Lin, Jinhuang; Lin, Junming; Kui, Guoju; Zhang, Jianhua; Yu, Yigang

    2014-01-01

    Previous studies have shown that vagus nerve stimulation can improve the prognosis of traumatic brain injury. The aim of this study was to elucidate the mechanism of the neuroprotective effects of vagus nerve stimulation in rabbits with brain explosive injury. Rabbits with brain explosive injury received continuous stimulation (10 V, 5 Hz, 5 ms, 20 minutes) of the right cervical vagus nerve. Tumor necrosis factor-α, interleukin-1β and interleukin-10 concentrations were detected in serum and brain tissues, and water content in brain tissues was measured. Results showed that vagus nerve stimulation could reduce the degree of brain edema, decrease tumor necrosis factor-α and interleukin-1β concentrations, and increase interleukin-10 concentration after brain explosive injury in rabbits. These data suggest that vagus nerve stimulation may exert neuroprotective effects against explosive injury via regulating the expression of tumor necrosis factor-α, interleukin-1β and interleukin-10 in the serum and brain tissue. PMID:25368644

  2. Laterality effects of human pudendal nerve stimulation on corticoanal pathways: evidence for functional asymmetry

    PubMed Central

    Hamdy, S; Enck, P; Aziz, Q; Uengoergil, S; Hobson, A; Thompson, D

    1999-01-01

    BACKGROUND—Although motor and sensory pathways to the human external anal sphincter are bilateral, a unilateral pudendal neuropathy may still disrupt anal continence. Anal continence can, however, be preserved despite unilateral pudendal damage, and so to explain those differing observations, we postulated that pudendal innervation might be asymmetric.
AIMS—To explore the individual effects of right and left pudendal nerve stimulation on the corticofugal pathways to the human external anal sphincter and thus assess evidence for functional asymmetric pelvic innervation.
METHODS—In eight healthy subjects, anal sphincter electromyographic responses, evoked to transcranial magnetic stimulation of the motor cortex, were recorded 5-500 msec after digital transrectal electrical conditioning stimuli applied to each pudendal nerve.
RESULTS—Right or left pudendal nerve stimulation evoked anal responses of similar latencies but asymmetric amplitudes in six subjects: dominant responses (>50% contralateral side) from the right pudendal in four subjects and from the left in two. Cortical stimulation also evoked anal responses with amplitude 448 (121) µV and latency 20.9 (1.1) msec. When cortical stimulation was preceded by pudendal nerve stimulation, the cortical responses were facilitated at interstimulus intervals of 5-20 msec. Dominant pudendal nerve stimulation induced greater facilitation of the cortically evoked responses than the non-dominant nerve.
CONCLUSIONS—Cortical pathways to the external anal sphincter are facilitated by pudendal nerve conditioning, in an asymmetric manner. This functional asymmetry may explain the presence and absence of anal incontinence after unilateral pudendal nerve injury.


Keywords: cerebral cortex; continence; electromyography; external anal sphincter; incontinence; magnetic stimulation PMID:10369705

  3. Pulsed laser versus electrical energy for peripheral nerve stimulation

    PubMed Central

    Wells, Jonathon; Konrad, Peter; Kao, Chris; Jansen, E. Duco; Mahadevan-Jansen, Anita

    2010-01-01

    Transient optical neural stimulation has previously been shown to elicit highly controlled, artifact-free potentials within the nervous system in a non-contact fashion without resulting in damage to tissue. This paper presents the physiologic validity of elicited nerve and muscle potentials from pulsed laser induced stimulation of the peripheral nerve in a comparative study with the standard method of electrically evoked potentials. Herein, the fundamental physical properties underlying the two techniques are contrasted. Key laser parameters for efficient optical stimulation of the peripheral nerve are detailed. Strength response curves are shown to be linear for each stimulation modality, although fewer axons can be recruited with optically evoked potentials. Results compare the relative transient energy requirements for stimulation using each technique and demonstrate that optical methods can selectively excite functional nerve stimulation. Adjacent stimulation and recording of compound nerve potentials in their entirety from optical and electrical stimulation are presented, with optical responses shown to be free of any stimulation artifact. Thus, use of a pulsed laser exhibits some advantages when compared to standard electrical means for excitation of muscle potentials in the peripheral nerve in the research domain and possibly for clinical diagnostics in the future. PMID:17537515

  4. Can ultrasound be used to stimulate nerve tissue?

    PubMed Central

    Norton, Stephen J

    2003-01-01

    Background The stimulation of nerve or cortical tissue by magnetic induction is a relatively new tool for the non-invasive study of the brain and nervous system. Transcranial magnetic stimulation (TMS), for example, has been used for the functional mapping of the motor cortex and may have potential for treating a variety of brain disorders. Methods and Results A new method of stimulating active tissue is proposed by propagating ultrasound in the presence of a magnetic field. Since tissue is conductive, particle motion created by an ultrasonic wave will induce an electric current density generated by Lorentz forces. An analytical derivation is given for the electric field distribution induced by a collimated ultrasonic beam. An example shows that peak electric fields of up to 8 V/m appear to be achievable at the upper range of diagnostic intensities. This field strength is about an order of magnitude lower than fields typically associated with TMS; however, the electric field gradients induced by ultrasound can be quite high (about 60 kV/m2 at 4 MHz), which theoretically play a more important role in activation than the field magnitude. The latter value is comparable to TMS-induced gradients. Conclusion The proposed method could be used to locally stimulate active tissue by inducing an electric field in regions where the ultrasound is focused. Potential advantages of this method compared to TMS is that stimulation of cortical tissue could be highly localized as well as achieved at greater depths in the brain than is currently possible with TMS. PMID:12702213

  5. Laryngeal elevation by selective stimulation of the hypoglossal nerve

    NASA Astrophysics Data System (ADS)

    Hadley, Aaron J.; Kolb, Ilya; Tyler, Dustin J.

    2013-08-01

    Objective. Laryngeal elevation protects the airway and assists opening of the esophagus during swallowing. The GH, thyrohyoid, and MH muscles provide a majority of this elevatory motion. This study applied functional electrical stimulation to the XII/C1 nerve complex using a nerve cuff electrode to determine the capabilities of neural stimulation to induce laryngeal elevation. Approach. Multi-contact FINE electrodes were implanted onto the XII/C1 nerve complex at locations proximal and distal to the thyrohyoid branching point in five anesthetized canines. Motion of the thyroid cartilage and the hyoid bone was recorded during stimulation of nerve cuffs and intramuscular electrodes. Main Results. Nerve stimulation induced 260% more laryngeal elevation than intramuscular stimulation (18.8 mm versus 5.2 mm, p ≪ 0.01), and 228% higher velocity (143.8 versus 43.9 mm s-1, p ≪ 0.01). While stimulation at all cuff and electrode locations elevated the larynx, only the proximal XII/C1 nerve cuff significantly elicited both thyroid-hyoid approximation and hyoid elevation. In all proximal XII/C1 nerve cuffs (n = 7), stimulation was able to obtain selectivity of greater than 75% of at least one elevatory muscle. Significance. These results support the hypothesis that an implanted neural interface system can produce increased laryngeal elevation, a significant protective mechanism of deglutition.

  6. Magnetic resonance imaging of optic nerve

    PubMed Central

    Gala, Foram

    2015-01-01

    Optic nerves are the second pair of cranial nerves and are unique as they represent an extension of the central nervous system. Apart from clinical and ophthalmoscopic evaluation, imaging, especially magnetic resonance imaging (MRI), plays an important role in the complete evaluation of optic nerve and the entire visual pathway. In this pictorial essay, the authors describe segmental anatomy of the optic nerve and review the imaging findings of various conditions affecting the optic nerves. MRI allows excellent depiction of the intricate anatomy of optic nerves due to its excellent soft tissue contrast without exposure to ionizing radiation, better delineation of the entire visual pathway, and accurate evaluation of associated intracranial pathologies. PMID:26752822

  7. Stimulation of the human auditory nerve with optical radiation

    NASA Astrophysics Data System (ADS)

    Fishman, Andrew; Winkler, Piotr; Mierzwinski, Jozef; Beuth, Wojciech; Izzo Matic, Agnella; Siedlecki, Zygmunt; Teudt, Ingo; Maier, Hannes; Richter, Claus-Peter

    2009-02-01

    A novel, spatially selective method to stimulate cranial nerves has been proposed: contact free stimulation with optical radiation. The radiation source is an infrared pulsed laser. The Case Report is the first report ever that shows that optical stimulation of the auditory nerve is possible in the human. The ethical approach to conduct any measurements or tests in humans requires efficacy and safety studies in animals, which have been conducted in gerbils. This report represents the first step in a translational research project to initiate a paradigm shift in neural interfaces. A patient was selected who required surgical removal of a large meningioma angiomatum WHO I by a planned transcochlear approach. Prior to cochlear ablation by drilling and subsequent tumor resection, the cochlear nerve was stimulated with a pulsed infrared laser at low radiation energies. Stimulation with optical radiation evoked compound action potentials from the human auditory nerve. Stimulation of the auditory nerve with infrared laser pulses is possible in the human inner ear. The finding is an important step for translating results from animal experiments to human and furthers the development of a novel interface that uses optical radiation to stimulate neurons. Additional measurements are required to optimize the stimulation parameters.

  8. Optical stimulation of the facial nerve: a surgical tool?

    NASA Astrophysics Data System (ADS)

    Richter, Claus-Peter; Teudt, Ingo Ulrik; Nevel, Adam E.; Izzo, Agnella D.; Walsh, Joseph T., Jr.

    2008-02-01

    One sequela of skull base surgery is the iatrogenic damage to cranial nerves. Devices that stimulate nerves with electric current can assist in the nerve identification. Contemporary devices have two main limitations: (1) the physical contact of the stimulating electrode and (2) the spread of the current through the tissue. In contrast to electrical stimulation, pulsed infrared optical radiation can be used to safely and selectively stimulate neural tissue. Stimulation and screening of the nerve is possible without making physical contact. The gerbil facial nerve was irradiated with 250-μs-long pulses of 2.12 μm radiation delivered via a 600-μm-diameter optical fiber at a repetition rate of 2 Hz. Muscle action potentials were recorded with intradermal electrodes. Nerve samples were examined for possible tissue damage. Eight facial nerves were stimulated with radiant exposures between 0.71-1.77 J/cm2, resulting in compound muscle action potentials (CmAPs) that were simultaneously measured at the m. orbicularis oculi, m. levator nasolabialis, and m. orbicularis oris. Resulting CmAP amplitudes were 0.3-0.4 mV, 0.15-1.4 mV and 0.3-2.3 mV, respectively, depending on the radial location of the optical fiber and the radiant exposure. Individual nerve branches were also stimulated, resulting in CmAP amplitudes between 0.2 and 1.6 mV. Histology revealed tissue damage at radiant exposures of 2.2 J/cm2, but no apparent damage at radiant exposures of 2.0 J/cm2.

  9. Heart Stimulation by Time-Varying Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Masuhiro; Andoh, Tomio; Goto, Tsuneaki; Hosono, Akihiko; Kawakami, Tadashi; Okumura, Fukuichiro; Takenaka, Toshifumi; Yamamoto, Isao

    1992-07-01

    A strong magnetic stimulator adopted for cardiac muscle was constructed with the stored energy of 50 kJ. Pulsed magnetic fields were applied to dog hearts with normal activity from outside of the body. The magnetic stimulus triggered on the T wave of the electrocardiograph caused arrhythmias in the first and second beats after the stimulus. It has been confirmed that this magnetic effect is due to a direct stimulation of cardiac muscle, not to an indirect stimulation on the vagus nerve. The threshold strength was determined for different pulse durations. The obtained strength-duration relationship is comparable to that for the electric stimulation of the dog heart.

  10. A Computational Framework for Electrical Stimulation of Vestibular Nerve.

    PubMed

    Marianelli, Prisca; Capogrosso, Marco; Bassi Luciani, Lorenzo; Panarese, Alessandro; Micera, Silvestro

    2015-09-01

    The vestibular organs are very important to generate reflexes critical for stabilizing gaze and body posture. Vestibular diseases significantly reduce the quality of life of people who are affected by them. Some research groups have recently started developing vestibular neuroprostheses to mitigate these symptoms. However, many scientific and technological issues need to be addressed to optimise their use in clinical trials. We developed a computational model able to mimic the response of human vestibular nerves and which can be exploited for "in-silico" testing of new strategies to design implantable vestibular prostheses. First, a digital model of the vestibular system was reconstructed from anatomical data. Monopolar stimulation was delivered at different positions and distances from ampullary nerves. The electrical potential induced by the injected current was computed through finite-element methods and drove extra-cellular stimulation of fibers in the vestibular, facial, and cochlear nerves. The electrical activity of vestibular nerves and the resulting eye movements elicited by different stimulation protocols were investigated. A set of electrode configurations was analyzed in terms of selectivity at increasing injected current. Electrode position along the nerve plays a major role in producing undesired activity in other nontargeted nerves, whereas distance from the fiber does not significantly affect selectivity. Indications are provided to minimize misalignment in nonoptimal electrode locations. Eye movements elicited by the different stimulation protocols are calculated and compared to experimental values, for the purpose of model validation. PMID:25751868

  11. [Implantable nerve stimulation for obstructive sleep apnea hypopnea syndrome].

    PubMed

    Afonso Delgado, Lidia; Micoulaud Franchi, Jean-Arthur; Monteyrol, Pierre-Jean; Philip, Pierre

    2016-02-01

    Obstructive sleep apnea hypopnea syndrome (OSAHS) is a common disorder that has been identified as a contributor to cardiovascular disease making it a major public health problem. Continuous positive airway pressure is the standard treatment but compliance is suboptimal. Mandibular advancement devices and surgery have limited indications, inconstant efficiency and potential irreversible side effects. Stimulation of the hypoglossal nerve, that innervates the genioglossus, a protrusor muscle of the tongue, is now a new treatment option for moderate and severe cases of OSAHS. Two types of stimulation are currently available: stimulation synchronous with inspiration and continuous stimulation. The indication of each type of stimulation and long-term effects still need to be assessed but the implantable nerve stimulation is a promising treatment for patients without a therapy solution so far.

  12. Diabetic neuropathy increases stimulation threshold during popliteal sciatic nerve block†

    PubMed Central

    Heschl, S.; Hallmann, B.; Zilke, T.; Gemes, G.; Schoerghuber, M.; Auer-Grumbach, M.; Quehenberger, F.; Lirk, P.; Hogan, Q.; Rigaud, M.

    2016-01-01

    Background Peripheral nerve stimulation is commonly used for nerve localization in regional anaesthesia, but recommended stimulation currents of 0.3–0.5 mA do not reliably produce motor activity in the absence of intraneural needle placement. As this may be particularly true in patients with diabetic neuropathy, we examined the stimulation threshold in patients with and without diabetes. Methods Preoperative evaluation included a neurological exam and electroneurography. During ultrasound-guided popliteal sciatic nerve block, we measured the current required to produce motor activity for the tibial and common peroneal nerve in diabetic and non-diabetic patients. Proximity to the nerve was evaluated post-hoc using ultrasound imaging. Results Average stimulation currents did not differ between diabetic (n=55) and non-diabetic patients (n=52). Although the planned number of patients was not reached, the power goal for the mean stimulation current was met. Subjects with diminished pressure perception showed increased thresholds for the common peroneal nerve (median 1.30 vs. 0.57 mA in subjects with normal perception, P=0.042), as did subjects with decreased pain sensation (1.60 vs. 0.50 mA in subjects with normal sensation, P=0.038). Slowed ulnar nerve conduction velocity predicted elevated mean stimulation current (r=−0.35, P=0.002). Finally, 15 diabetic patients required more than 0.5 mA to evoke a motor response, despite intraneural needle placement (n=4), or required currents ≥2 mA despite needle-nerve contact, vs three such patients (1 intraneural, 2 with ≥2 mA) among non-diabetic patients (P=0.003). Conclusions These findings suggest that stimulation thresholds of 0.3–0.5 mA may not reliably determine close needle-nerve contact during popliteal sciatic nerve block, particularly in patients with diabetic neuropathy. Clinical trial registration NCT01488474 PMID:26994231

  13. Differential fiber-specific block of nerve conduction in mammalian peripheral nerves using kilohertz electrical stimulation

    PubMed Central

    Patel, Yogi A.

    2015-01-01

    Kilohertz electrical stimulation (KES) has been shown to induce repeatable and reversible nerve conduction block in animal models. In this study, we characterized the ability of KES stimuli to selectively block specific components of stimulated nerve activity using in vivo preparations of the rat sciatic and vagus nerves. KES stimuli in the frequency range of 5–70 kHz and amplitudes of 0.1–3.0 mA were applied. Compound action potentials were evoked using either electrical or sensory stimulation, and block of components was assessed through direct nerve recordings and muscle force measurements. Distinct observable components of the compound action potential had unique conduction block thresholds as a function of frequency of KES. The fast component, which includes motor activity, had a monotonically increasing block threshold as a function of the KES frequency. The slow component, which includes sensory activity, showed a nonmonotonic block threshold relationship with increasing KES frequency. The distinct trends with frequency of the two components enabled selective block of one component with an appropriate choice of frequency and amplitude. These trends in threshold of the two components were similar when studying electrical stimulation and responses of the sciatic nerve, electrical stimulation and responses of the vagus nerve, and sensorimotor stimulation and responses of the sciatic nerve. This differential blocking effect of KES on specific fibers can extend the applications of KES conduction block to selective block and stimulation of neural signals for neuromodulation as well as selective control of neural circuits underlying sensorimotor function. PMID:25878155

  14. Centrally administered glucagon stimulates sympathetic nerve activity in rat.

    PubMed

    Krzeski, R; Czyzyk-Krzeska, M F; Trzebski, A; Millhorn, D E

    1989-12-18

    The effect of pancreatic glucagon given intravenously, intracerebroventricularly and microinjected into the nucleus of the solitary tract on sympathetic activity in the cervical trunk and adrenal nerve was examined in rat. In each case glucagon caused a relatively long-lasting substantial increase in discharge of both nerves. This finding shows that glucagon can act centrally to stimulate sympathetic activity. The most probable site for the sympathoexcitatory effect of glucagon is the nucleus of the solitary tract. PMID:2598031

  15. Assessment of Neuromuscular Function Using Percutaneous Electrical Nerve Stimulation.

    PubMed

    Rozand, Vianney; Grosprêtre, Sidney; Stapley, Paul J; Lepers, Romuald

    2015-09-13

    Percutaneous electrical nerve stimulation is a non-invasive method commonly used to evaluate neuromuscular function from brain to muscle (supra-spinal, spinal and peripheral levels). The present protocol describes how this method can be used to stimulate the posterior tibial nerve that activates plantar flexor muscles. Percutaneous electrical nerve stimulation consists of inducing an electrical stimulus to a motor nerve to evoke a muscular response. Direct (M-wave) and/or indirect (H-reflex) electrophysiological responses can be recorded at rest using surface electromyography. Mechanical (twitch torque) responses can be quantified with a force/torque ergometer. M-wave and twitch torque reflect neuromuscular transmission and excitation-contraction coupling, whereas H-reflex provides an index of spinal excitability. EMG activity and mechanical (superimposed twitch) responses can also be recorded during maximal voluntary contractions to evaluate voluntary activation level. Percutaneous nerve stimulation provides an assessment of neuromuscular function in humans, and is highly beneficial especially for studies evaluating neuromuscular plasticity following acute (fatigue) or chronic (training/detraining) exercise.

  16. Patterned sensory nerve stimulation enhances the reactivity of spinal Ia inhibitory interneurons.

    PubMed

    Kubota, Shinji; Hirano, Masato; Morishita, Takuya; Uehara, Kazumasa; Funase, Kozo

    2015-03-25

    Patterned sensory nerve stimulation has been shown to induce plastic changes in the reciprocal Ia inhibitory circuit. However, the mechanisms underlying these changes have not yet been elucidated in detail. The aim of the present study was to determine whether the reactivity of Ia inhibitory interneurons could be altered by patterned sensory nerve stimulation. The degree of reciprocal Ia inhibition, the conditioning effects of transcranial magnetic stimulation (TMS) on the soleus (SOL) muscle H-reflex, and the ratio of the maximum H-reflex amplitude versus maximum M-wave (H(max)/M(max)) were examined in 10 healthy individuals. Patterned electrical nerve stimulation was applied to the common peroneal nerve every 1 s (100 Hz-5 train) at the motor threshold intensity of tibialis anterior muscle to induce activity changes in the reciprocal Ia inhibitory circuit. Reciprocal Ia inhibition, the TMS-conditioned H-reflex amplitude, and H(max)/M(max) were recorded before, immediately after, and 15 min after the electrical stimulation. The patterned electrical nerve stimulation significantly increased the degree of reciprocal Ia inhibition and decreased the amplitude of the TMS-conditioned H-reflex in the short-latency inhibition phase, which was presumably mediated by Ia inhibitory interneurons. However, it had no effect on H(max)/M(max). Our results indicated that patterned sensory nerve stimulation could modulate the activity of Ia inhibitory interneurons, and this change may have been caused by the synaptic modification of Ia inhibitory interneuron terminals. These results may lead to a clearer understanding of the spinal cord synaptic plasticity produced by repetitive sensory inputs.

  17. 21 CFR 882.5870 - Implanted peripheral nerve stimulator for pain relief.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Implanted peripheral nerve stimulator for pain....5870 Implanted peripheral nerve stimulator for pain relief. (a) Identification. An implanted peripheral nerve stimulator for pain relief is a device that is used to stimulate electrically a peripheral...

  18. 21 CFR 882.5870 - Implanted peripheral nerve stimulator for pain relief.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Implanted peripheral nerve stimulator for pain....5870 Implanted peripheral nerve stimulator for pain relief. (a) Identification. An implanted peripheral nerve stimulator for pain relief is a device that is used to stimulate electrically a peripheral...

  19. 21 CFR 882.5870 - Implanted peripheral nerve stimulator for pain relief.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Implanted peripheral nerve stimulator for pain....5870 Implanted peripheral nerve stimulator for pain relief. (a) Identification. An implanted peripheral nerve stimulator for pain relief is a device that is used to stimulate electrically a peripheral...

  20. 21 CFR 882.5870 - Implanted peripheral nerve stimulator for pain relief.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Implanted peripheral nerve stimulator for pain....5870 Implanted peripheral nerve stimulator for pain relief. (a) Identification. An implanted peripheral nerve stimulator for pain relief is a device that is used to stimulate electrically a peripheral...

  1. 21 CFR 882.5870 - Implanted peripheral nerve stimulator for pain relief.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implanted peripheral nerve stimulator for pain....5870 Implanted peripheral nerve stimulator for pain relief. (a) Identification. An implanted peripheral nerve stimulator for pain relief is a device that is used to stimulate electrically a peripheral...

  2. Magnetically stimulated fluid flow patterns

    ScienceCinema

    Martin, Jim; Solis, Kyle

    2016-07-12

    Sandia National Laboratories' Jim Martin and Kyle Solis explain research on the effects of magnetic fields on fluid flows and how they stimulate vigorous flows. Fluid flow is a necessary phenomenon in everything from reactors to cooling engines in cars.

  3. Magnetically stimulated fluid flow patterns

    SciTech Connect

    Martin, Jim; Solis, Kyle

    2014-03-06

    Sandia National Laboratories' Jim Martin and Kyle Solis explain research on the effects of magnetic fields on fluid flows and how they stimulate vigorous flows. Fluid flow is a necessary phenomenon in everything from reactors to cooling engines in cars.

  4. Optimization of a wearable pudendal nerve stimulator using computational models.

    PubMed

    Shiraz, Arsam N; Leaker, Brian; Demosthenous, Andreas

    2015-01-01

    After spinal cord injury, lower urinary tract functions may be disrupted. Trans-rectal stimulation of the pudendal nerve may enable patients to regain these functions via minimally invasive means. Using a finite element model of a wearable trans-rectal stimulator in the pelvic region, and a computational model of mammalian nerve fiber, various electrode configurations and the corresponding required current levels were studied. A configuration requiring considerably lower current level than previously reported was identified. For this configuration, the strength-duration curve was simulated and the effect of different stimulus waveforms on the required current was studied. In addition, the study examined whether a multi-electrode device could selectively activate different terminal branches of the pudendal nerve.

  5. Optimization of a wearable pudendal nerve stimulator using computational models.

    PubMed

    Shiraz, Arsam N; Leaker, Brian; Demosthenous, Andreas

    2015-01-01

    After spinal cord injury, lower urinary tract functions may be disrupted. Trans-rectal stimulation of the pudendal nerve may enable patients to regain these functions via minimally invasive means. Using a finite element model of a wearable trans-rectal stimulator in the pelvic region, and a computational model of mammalian nerve fiber, various electrode configurations and the corresponding required current levels were studied. A configuration requiring considerably lower current level than previously reported was identified. For this configuration, the strength-duration curve was simulated and the effect of different stimulus waveforms on the required current was studied. In addition, the study examined whether a multi-electrode device could selectively activate different terminal branches of the pudendal nerve. PMID:26737021

  6. An implant for chronic selective stimulation of nerves.

    PubMed

    Bugbee, M; Donaldson, N N; Lickel, A; Rijkhoff, N J; Taylor, J

    2001-01-01

    An implantable stimulator system has been developed for nerve stimulation. The system is capable of stimulating selectively, either by fibre position, fibre size or by sending action potentials in one direction only, based on the use of nerve cuffs. The stimulator produces either quasi-trapezoidal current pulses, to allow anodal blocking, or conventional rectangular-shaped current pulses, of amplitude 20 microA to 5 mA (in 20 microA steps) with duration of 16 micros to 1 ms (in 8 micros steps). For safety, both active and passive charge balancing is used. The amplitude of the active charge-balancing phase can be varied between 1/7 and 1/47 of the pulse amplitude. During manufacture, each implant is customised so as to drive either 6 quasi-tripolar (dipolar), 4 tripolar or 2 pentapolar cuffs. Possible applications of the device are: improved defaecation and bladder voiding after spinal cord injury, by stimulation of the sacral motor roots; neuromodulation to reduce hyperreflexia without concomitant muscle contractions; in stroke patients, to enable balanced inversion-eversion while dorsiflexing the ankle by stimulating the peroneal nerve. It may also be used in chronic animal experiments.This paper describes the implant system, its hardware and communication protocol, and shows results from in vitro tests of the device and the first acute anodal-blocking experiments in pigs. PMID:11344005

  7. Infrared neural stimulation of human spinal nerve roots in vivo

    PubMed Central

    Cayce, Jonathan M.; Wells, Jonathon D.; Malphrus, Jonathan D.; Kao, Chris; Thomsen, Sharon; Tulipan, Noel B.; Konrad, Peter E.; Jansen, E. Duco; Mahadevan-Jansen, Anita

    2015-01-01

    Abstract. Infrared neural stimulation (INS) is a neurostimulation modality that uses pulsed infrared light to evoke artifact-free, spatially precise neural activity with a noncontact interface; however, the technique has not been demonstrated in humans. The objective of this study is to demonstrate the safety and efficacy of INS in humans in vivo. The feasibility of INS in humans was assessed in patients (n=7) undergoing selective dorsal root rhizotomy, where hyperactive dorsal roots, identified for transection, were stimulated in vivo with INS on two to three sites per nerve with electromyogram recordings acquired throughout the stimulation. The stimulated dorsal root was removed and histology was performed to determine thermal damage thresholds of INS. Threshold activation of human dorsal rootlets occurred in 63% of nerves for radiant exposures between 0.53 and 1.23  J/cm2. In all cases, only one or two monitored muscle groups were activated from INS stimulation of a hyperactive spinal root identified by electrical stimulation. Thermal damage was first noted at 1.09  J/cm2 and a 2∶1 safety ratio was identified. These findings demonstrate the success of INS as a fresh approach for activating human nerves in vivo and providing the necessary safety data needed to pursue clinically driven therapeutic and diagnostic applications of INS in humans. PMID:26157986

  8. 21 CFR 868.2775 - Electrical peripheral nerve stimulator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... a device used to apply an electrical current to a patient to test the level of pharmacological... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Electrical peripheral nerve stimulator. 868.2775... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2775 Electrical peripheral...

  9. 21 CFR 868.2775 - Electrical peripheral nerve stimulator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... a device used to apply an electrical current to a patient to test the level of pharmacological... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electrical peripheral nerve stimulator. 868.2775... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2775 Electrical peripheral...

  10. 21 CFR 868.2775 - Electrical peripheral nerve stimulator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... a device used to apply an electrical current to a patient to test the level of pharmacological... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Electrical peripheral nerve stimulator. 868.2775... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2775 Electrical peripheral...

  11. 21 CFR 868.2775 - Electrical peripheral nerve stimulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... a device used to apply an electrical current to a patient to test the level of pharmacological... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Electrical peripheral nerve stimulator. 868.2775... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2775 Electrical peripheral...

  12. 21 CFR 868.2775 - Electrical peripheral nerve stimulator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... a device used to apply an electrical current to a patient to test the level of pharmacological... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Electrical peripheral nerve stimulator. 868.2775... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2775 Electrical peripheral...

  13. 21 CFR 870.3850 - Carotid sinus nerve stimulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Carotid sinus nerve stimulator. 870.3850 Section 870.3850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3850 Carotid...

  14. 21 CFR 870.3850 - Carotid sinus nerve stimulator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Carotid sinus nerve stimulator. 870.3850 Section 870.3850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3850 Carotid...

  15. 21 CFR 874.1820 - Surgical nerve stimulator/locator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Surgical nerve stimulator/locator. 874.1820 Section 874.1820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1820 Surgical...

  16. 21 CFR 874.1820 - Surgical nerve stimulator/locator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Surgical nerve stimulator/locator. 874.1820 Section 874.1820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1820 Surgical...

  17. 21 CFR 874.1820 - Surgical nerve stimulator/locator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Surgical nerve stimulator/locator. 874.1820 Section 874.1820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1820 Surgical...

  18. Deafness alters auditory nerve fibre responses to cochlear implant stimulation.

    PubMed

    Sly, David J; Heffer, Leon F; White, Mark W; Shepherd, Robert K; Birch, Michael G J; Minter, Ricki L; Nelson, Niles E; Wise, Andrew K; O'Leary, Stephen J

    2007-07-01

    Here we characterized the relationship between duration of sensorineural hearing loss and the response of the auditory nerve to electrical stimulus rate. Electrophysiological recordings were made from undeafened guinea pigs and those ototoxically deafened for either 5 weeks or 6 months. Auditory neuron survival decreased significantly with the duration of deafness. Extracellular recordings were made from auditory nerve fibres responding to biphasic, charge-balanced current pulses delivered at rates of 20 and 200 pulses/s via a monopolar scala tympani stimulating electrode. The response to 20 pulses/s electrical stimulation of the deafened cochlea exhibited a decrease in spike latency, unaltered temporal jitter and unaltered dynamic range (of nerve firing rate against stimulus current), and a reduction in threshold after 6 months of deafness. The response to a 200-pulse/s stimulus was similar except that the dynamic range was greater than with 20 pulses/s and was also greater in deafened animals than in undeafened animals. Deafness and pulse rate are related; in deaf animals spike recovery appears to be complete between successive stimulus pulses at a low rate (20 pulses/s), but incomplete between pulses at a moderate pulse rate (200 pulses/s). These results suggest that changes in the function of individual auditory nerve fibres after deafness may affect clinical responses during high-rate stimulation such as that used in contemporary speech processing strategies, but not during lower rate stimulation such as that used to record evoked potentials. PMID:17650121

  19. Electrical stimulation of nerve cells using conductive nanofibrous scaffolds for nerve tissue engineering.

    PubMed

    Ghasemi-Mobarakeh, Laleh; Prabhakaran, Molamma P; Morshed, Mohammad; Nasr-Esfahani, Mohammad Hossein; Ramakrishna, Seeram

    2009-11-01

    Fabrication of scaffolds with suitable chemical, mechanical, and electrical properties is critical for the success of nerve tissue engineering. Electrical stimulation was directly applied to electrospun conductive nanofibrous scaffolds to enhance the nerve regeneration process. In the present study, electrospun conductive nanofibers were prepared by mixing 10 and 15 wt% doped polyaniline (PANI) with poly (epsilon-caprolactone)/gelatin (PG) (70:30) solution (PANI/PG) by electrospinning. The fiber diameter, pore size, hydrophilicity, tensile properties, conductivity, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy spectra of nanofibers were determined, and the in vitro biodegradability of the different nanofibrous scaffolds was also evaluated. Nanofibrous scaffolds containing 15% PANI was found to exhibit the most balanced properties to meet all the required specifications for electrical stimulation for its enhanced conductivity and is used for in vitro culture and electrical stimulation of nerve stem cells. 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and scanning electron microscopy results showed that conductive nanofibrous scaffolds are suitable substrates for the attachment and proliferation of nerve stem cells. Electrical stimulation through conductive nanofibrous PANI/PG scaffolds showed enhanced cell proliferation and neurite outgrowth compared to the PANI/PG scaffolds that were not subjected to electrical stimulation.

  20. Electrical stimulation of the hypoglossal nerve: a potential therapy.

    PubMed

    Schwartz, Alan R; Smith, Philip L; Oliven, Arie

    2014-02-01

    Obstructive sleep apnea is characterized by recurrent episodes of pharyngeal collapse, which result from a decrease in pharyngeal dilator muscle tone. The genioglossus is a major pharyngeal dilator that maintains airway patency during sleep. Early studies in animal and humans have demonstrated that electrical stimulation of this muscle reduces pharyngeal collapsibility, increases airflow, and mitigates obstructive sleep apnea. These findings impelled the development of fully implantable hypoglossal nerve stimulating systems (HGNS), for which feasibility trial results are now available. These pilot studies have confirmed that hypoglossal nerve stimulation can prevent pharyngeal collapse without arousing patients from sleep. Potentially, a substantial segment of the patient population with obstructive sleep apnea can be treated with this novel approach. Furthermore, the feasibility trial findings suggest that the therapeutic potential of HGNS can be optimized by selecting patients judiciously, titrating the stimulus intensity optimally, and characterizing the underlying function and anatomy of the pharynx. These strategies are currently being examined in ongoing pivotal trials of HGNS.

  1. Optical stimulation of the prostate nerves: A potential diagnostic technique

    NASA Astrophysics Data System (ADS)

    Tozburun, Serhat

    There is wide variability in sexual potency rates (9--86%) after nerve-sparing prostate cancer surgery due to limited knowledge of the location of the cavernous nerves (CN's) on the prostate surface, which are responsible for erectile function. Thus, preservation of the CN's is critical in preserving a man's ability to have spontaneous erections following surgery. Nerve-mapping devices, utilizing conventional Electrical Nerve Stimulation (ENS) techniques, have been used as intra-operative diagnostic tools to assist in preservation of the CN. However, these technologies have proven inconsistent and unreliable in identifying the CN's due to the need for physical contact, the lack of spatial selectivity, and the presence of electrical artifacts in measurements. Optical Nerve Stimulation (ONS), using pulsed infrared laser radiation, is studied as an alternative to ENS. The objective of this study is sevenfold: (1) to develop a laparoscopic laser probe for ONS of the CN's in a rat model, in vivo; (2) to demonstrate faster ONS using continuous-wave infrared laser radiation; (3) to describe and characterize the mechanism of successful ONS using alternative laser wavelengths; (4) to test a compact, inexpensive all-single-mode fiber configuration for optical stimulation of the rat CN studies; (5) to implement fiber optic beam shaping methods for comparison of Gaussian and flat-top spatial beam profiles during ONS; (6) to demonstrate successful ONS of CN's through a thin layer of fascia placed over the nerve and prostate gland; and (7) to verify the experimentally determined therapeutic window for safe and reliable ONS without thermal damage to the CN's by comparison with a computational model for thermal damage. A 5.5-Watt Thulium fiber laser operated at 1870 nm and two pigtailed, single mode, near-IR diode lasers (150-mW, 1455-nm laser and 500-mW, 1550-nm laser) were used for non-contact stimulation of the rat CN's. Successful laser stimulation, as measured by an

  2. Pudendal Nerve Stimulation and Block by a Wireless Controlled Implantable Stimulator in Cats

    PubMed Central

    Yang, Guangning; Wang, Jicheng; Shen, Bing; Roppolo, James R.; de Groat, William C.; Tai, Changfeng

    2014-01-01

    Objective To determine the functionality of a wireless controlled implantable stimulator designed for stimulation and block of the pudendal nerve. Materials and Methods In 5 cats under α-chloralose anesthesia, the stimulator was implanted underneath the skin on the left side in the lower back along the sacral spine. Two tripolar cuff electrodes were implanted bilaterally on the pudendal nerves in addition to one bipolar cuff electrode that was implanted on the left side central to the tripolar cuff electrode. The stimulator provided high frequency (5-20 kHz) biphasic stimulation waveforms to the two tripolar electrodes and low frequency (1-100 Hz) rectangular pulses to the bipolar electrode. Bladder and urethral pressures were measured to determine the effects of pudendal nerve stimulation (PNS) or block. Results The maximal (70-100 cmH2O) urethral pressure generated by 20 Hz PNS applied via the bipolar electrode was completely eliminated by the pudendal nerve block induced by the high frequency stimulation (6-15 kHz, 6-10 V) applied via the two tripolar electrodes. In a partially filled bladder 20-30 Hz PNS (2-8 V, 0.2 ms) but not 5 Hz stimulation applied via the bipolar electrode elicited a large sustained bladder contraction (45.9±13.4 to 52.0±22 cmH2O). During cystometry, the 5 Hz PNS significantly (P<0.05) increased bladder capacity to 176.5±27.1% of control capacity. Conclusions The wireless controlled implantable stimulator successfully generated the required waveforms for stimulation and block of pudendal nerve, which will be useful for restoring bladder functions after spinal cord injury (SCI). PMID:24320615

  3. Mesencephalic stimulation elicits inhibition of phrenic nerve activity in cat.

    PubMed

    Gallman, E A; Lawing, W L; Millhorn, D E

    1991-05-01

    1. Previous work from this laboratory has indicated that the mesencephalon is the anatomical substrate for a mechanism capable of inhibiting central respiratory drive in glomectomized cats for periods of up to 1 h or more following brief exposure to systemic hypoxia; phrenic nerve activity was used as an index of central respiratory drive. 2. The present study was undertaken to further localize the region responsible for the observed post-hypoxic inhibition of respiratory drive. We studied the phrenic nerve response to stimulations of the mesencephalon in anaesthetized, paralysed peripherally chemo-denervated cats with end-expired PCO2 and body temperature servo-controlled. 3. Stimulations of two types were employed. Electrical stimulation allowed rapid determination of sites from which phrenic inhibition could be elicited. Microinjections of excitatory amino acids were used subsequently in order to confine excitation to neuronal cell bodies and not axons of passage. 4. Stimulation of discrete regions of the ventromedial aspect of the mesencephalon in the vicinity of the red nucleus produced substantial inhibition of phrenic activity which lasted up to 45 min. Stimulation of other areas of the mesencephalon either produced no phrenic inhibition or resulted in a slight stimulation of phrenic activity. 5. The results are discussed in the context of the central respiratory response to hypoxia. PMID:1676420

  4. Vagus nerve stimulation attenuates the systemic inflammatory response to endotoxin

    NASA Astrophysics Data System (ADS)

    Borovikova, Lyudmila V.; Ivanova, Svetlana; Zhang, Minghuang; Yang, Huan; Botchkina, Galina I.; Watkins, Linda R.; Wang, Haichao; Abumrad, Naji; Eaton, John W.; Tracey, Kevin J.

    2000-05-01

    Vertebrates achieve internal homeostasis during infection or injury by balancing the activities of proinflammatory and anti-inflammatory pathways. Endotoxin (lipopolysaccharide), produced by all gram-negative bacteria, activates macrophages to release cytokines that are potentially lethal. The central nervous system regulates systemic inflammatory responses to endotoxin through humoral mechanisms. Activation of afferent vagus nerve fibres by endotoxin or cytokines stimulates hypothalamic-pituitary-adrenal anti-inflammatory responses. However, comparatively little is known about the role of efferent vagus nerve signalling in modulating inflammation. Here, we describe a previously unrecognized, parasympathetic anti-inflammatory pathway by which the brain modulates systemic inflammatory responses to endotoxin. Acetylcholine, the principle vagal neurotransmitter, significantly attenuated the release of cytokines (tumour necrosis factor (TNF), interleukin (IL)-1β, IL-6 and IL-18), but not the anti-inflammatory cytokine IL-10, in lipopolysaccharide-stimulated human macrophage cultures. Direct electrical stimulation of the peripheral vagus nerve in vivo during lethal endotoxaemia in rats inhibited TNF synthesis in liver, attenuated peak serum TNF amounts, and prevented the development of shock.

  5. Vestibular stimulation by magnetic fields

    PubMed Central

    Ward, Bryan K.; Roberts, Dale C.; Della Santina, Charles C.; Carey, John P.; Zee, David S.

    2015-01-01

    Individuals working next to strong static magnetic fields occasionally report disorientation and vertigo. With the increasing strength of magnetic fields used for magnetic resonance imaging (MRI) studies, these reports have become more common. It was recently learned that humans, mice and zebrafish all demonstrate behaviors consistent with constant peripheral vestibular stimulation while inside a strong, static magnetic field. The proposed mechanism for this effect involves a Lorentz force resulting from the interaction of a strong static magnetic field with naturally occurring ionic currents flowing through the inner ear endolymph into vestibular hair cells. The resulting force within the endolymph is strong enough to displace the lateral semicircular canal cupula, inducing vertigo and the horizontal nystagmus seen in normal mice and in humans. This review explores the evidence for interactions of magnetic fields with the vestibular system. PMID:25735662

  6. Giant early components of somatosensory evoked potentials to tibial nerve stimulation in cortical myoclonus.

    PubMed

    Anzellotti, Francesca; Onofrj, Marco; Bonanni, Laura; Saracino, Antonio; Franciotti, Raffaella

    2016-01-01

    Enlarged cortical components of somatosensory evoked potentials (giant SEPs) recorded by electroencephalography (EEG) and abnormal somatosensory evoked magnetic fields (SEFs) recorded by magnetoencephalography (MEG) are observed in the majority of patients with cortical myoclonus (CM). Studies on simultaneous recordings of SEPs and SEFs showed that generator mechanism of giant SEPs involves both primary sensory and motor cortices. However the generator sources of giant SEPs have not been fully understood as only one report describes clearly giant SEPs following lower limb stimulation. In our study we performed a combined EEG-MEG recording on responses elicited by electric median and tibial nerve stimulation in a patient who developed consequently to methyl bromide intoxication CM with giant SEPs to median and tibial nerve stimuli. SEPs wave shapes were identified on the basis of polarity-latency components (e.g. P15-N20-P25) as defined by earlier studies and guidelines. At EEG recording, the SEP giant component did not appear in the latency range of the first cortical component for median nerve SEP (N20), but appeared instead in the range of the P37 tibial nerve SEP, which is currently identified as the first cortical component elicited by tibial nerve stimuli. Our MEG and EEG SEPs recordings also showed that components in the latency range of P37 were preceded by other cortical components. These findings suggest that lower limb P37 does not correspond to upper limb N20. MEG results confirmed that giant SEFs are the second component from both tibial (N43m-P43m) and median (N27m-P27m) nerve stimulation. MEG dipolar sources of these giant components were located in the primary sensory and motor area. PMID:27489768

  7. Cortical Brain Mapping of Peripheral Nerves Using Functional Magnetic Resonance Imaging in a Rodent Model

    PubMed Central

    Cho, Younghoon R.; Jones, Seth R.; Pawela, Christopher P.; Li, Rupeng; Kao, Dennis S.; Schulte, Marie L.; Runquist, Matthew L.; Yan, Ji-Geng; Hudetz, Anthony G.; Jaradeh, Safwan S.; Hyde, James S.; Matloub, Hani S.

    2008-01-01

    The regions of the body have cortical and subcortical representation in proportion to their degree of innervation. The rat forepaw has been studied extensively in recent years using functional magnetic resonance imaging (fMRI)—typically by stimulation using electrodes directly inserted into the skin of the forepaw. Here, we stimulate using surgically implanted electrodes. A major distinction is that stimulation of the skin of the forepaw is mostly sensory, whereas direct nerve stimulation reveals not only the sensory system but also deep brain structures associated with motor activity. In this paper, we seek to define both the motor and sensory cortical and subcortical representations associated with the four major nerves of the rodent upper extremity. We electrically stimulated each nerve (median, ulnar, radial, and musculocutaneous) during fMRI acquisition using a 9.4T Bruker scanner. A current level of 0.5-1.0 mA and a frequency of 5 Hz were used while keeping the duration constant. A distinct pattern of cortical activation was found for each nerve that can be correlated with known sensorimotor afferent and efferent pathways to the rat forepaw. This direct nerve stimulation rat model can provide insight into peripheral nerve injury. PMID:18924070

  8. Electrical nerve stimulation for overactive bladder in children.

    PubMed

    Barroso, Ubirajara; Lordêlo, Patrícia

    2011-07-01

    Overactive bladder (OAB) is a urological condition that is frequently observed in children and requires treatment. Standard urotherapy is usually the first line of treatment; however, children with severe OAB do not respond to this therapy. Antimuscarinic drugs may be used, but complete resolution of symptoms with this medication is low. Studies, including two randomized clinical trials, have demonstrated that electrical nerve stimulation (ENS) can be used successfully for OAB in children. Electrodes have been placed in the genitals, anus, and intravesical area, and on the tibial posterior nerve, as well as used transcutaneously or implanted during a surgical procedure. This Review will discuss the use of ENS in children with OAB, with particular focus on the putative mechanisms of action, the different ENS techniques available, and clinical results for this therapy.

  9. Stimulation of the medial plantar nerve for complex regional pain syndrome.

    PubMed

    Mobbs, Ralph J; Lazarro, Amanda

    2010-11-01

    We describe a 47-year old male with complex regional pain syndrome II in the distribution of the medial plantar nerve following metatarsal fracture, which was treated with peripheral nerve stimulation. Using a new technique of nerve stimulation with a percutaneous-type electrode, the patient experienced sustained relief at 12 months follow-up. To our knowledge, this is the first report of peripheral neurostimulation effectively managing pain for the medial plantar nerve. PMID:20708936

  10. Enhancement of the amplitude of somatosensory evoked potentials following magnetic pulse stimulation of the human brain.

    PubMed

    Seyal, M; Browne, J K; Masuoka, L K; Gabor, A J

    1993-01-01

    In this study we have demonstrated an enhancement of cortically generated wave forms of the somatosensory evoked potential (SEP) following magnetic pulse stimulation of the human brain. Subcortically generated activity was unaltered. The enhancement of SEP amplitude was greatest when the median nerve was stimulated 30-70 msec following magnetic pulse stimulation over the contralateral parietal scalp. We posit that the enhancement of the SEP is the result of synchronization of pyramidal cells in the sensorimotor cortex resulting from the magnetic pulse.

  11. Functional regeneration of severed peripheral nerve using an implantable electrical stimulator.

    PubMed

    Lee, Tae Hyung; Pan, Hui; Kim, In Sook; Hwang, Soon Jung; Kim, Sung June

    2010-01-01

    This paper presents functional regeneration of severed peripheral nerve using a polymer-based implantable electrical stimulator. A polyimide based conduit electrode was made by micro-fabrication and a stimulation chip was designed to generate biphasic current pulse for electrical stimulation. The stimulation chip was packaged with a battery using silicone elastomer, and integrated with the electrode. The implantable electrical stimulator was implanted in the rat sciatic nerve with 7 mm gap. The electrical stimulation was applied for periods of one, two and four weeks between the proximal and the distal nerve stumps. After four weeks of post-operations, the degree of regeneration was evaluated through walking track assessments and by measuring neural response of the regenerated nerve. Based on these results, electrical stimulation, especially for two weeks of stimulation, could accelerate functional regeneration of the severed nerve.

  12. Continuous-wave infrared optical nerve stimulation for potential diagnostic applications

    NASA Astrophysics Data System (ADS)

    Tozburun, Serhat; Cilip, Christopher M.; Lagoda, Gwen A.; Burnett, Arthur L.; Fried, Nathaniel M.

    2010-09-01

    Optical nerve stimulation using infrared laser radiation has recently been developed as a potential alternative to electrical nerve stimulation. However, recent studies have focused primarily on pulsed delivery of the laser radiation and at relatively low pulse rates. The objective of this study is to demonstrate faster optical stimulation of the prostate cavernous nerves using continuous-wave (cw) infrared laser radiation for potential diagnostic applications. A thulium fiber laser (λ=1870 nm) is used for noncontact optical stimulation of the rat prostate cavernous nerves in vivo. Optical nerve stimulation, as measured by an intracavernous pressure (ICP) response in the penis, is achieved with the laser operating in either cw mode, or with a 5-ms pulse duration at 10, 20, 30, 40, 50, and 100 Hz. Successful optical stimulation is observed to be primarily dependent on a threshold nerve temperature (42 to 45 °C), rather than an incident fluence, as previously reported. cw optical nerve stimulation provides a significantly faster ICP response time using a lower power (and also less expensive) laser than pulsed stimulation. cw optical nerve stimulation may therefore represent an alternative mode of stimulation for intraoperative diagnostic applications where a rapid response is critical, such as identification of the cavernous nerves during prostate cancer surgery.

  13. Continuous-wave vs. pulsed infrared laser stimulation of the rat prostate cavernous nerves

    NASA Astrophysics Data System (ADS)

    Tozburun, Serhat; Cilip, Christopher M.; Lagoda, Gwen A.; Burnett, Arthur L.; Fried, Nathaniel M.

    2011-03-01

    Optical nerve stimulation has recently been developed as an alternative to electrical nerve stimulation. However, recent studies have focused primarily on pulsed delivery of the laser radiation and at relatively low pulse rates. The objective of this study is to demonstrate faster optical stimulation of the prostate cavernous nerves using continuouswave (CW) infrared laser radiation, for potential diagnostic applications. A Thulium fiber laser (λ = 1870 nm) was used for non-contact optical stimulation of the rat prostate cavernous nerves, in vivo. Optical nerve stimulation, as measured by an intracavernous pressure (ICP) response in the penis, was achieved with the laser operating in either CW mode, or with a 5-ms pulse duration at 10, 20, 30, 40, 50, and 100 Hz. Successful optical stimulation was observed to be primarily dependent on a threshold nerve temperature (42-45 °C), not an incident fluence, as previously reported. CW optical nerve stimulation provides a significantly faster ICP response time using a laser with lower power output than pulsed stimulation. CW optical nerve stimulation may therefore represent an alternative mode of stimulation for intra-operative diagnostic applications where a rapid response is critical, such as identification of the cavernous nerves during prostate cancer surgery.

  14. Vagus nerve stimulation for standardized monitoring: technical notes for conventional and endoscopic thyroidectomy.

    PubMed

    Dionigi, Gianlorenzo; Kim, Hoon Yub; Wu, Che-Wei; Lavazza, Matteo; Ferrari, Cesare; Leotta, Andrea; Spampatti, Sebastiano; Rovera, Francesca; Rausei, Stefano; Boni, Luigi; Chiang, Feng-Yu

    2013-09-01

    Standardization of the intraoperative neuromonitoring (IONM) technique is an essential aspect of modern monitored thyroid surgery. The standardized technique involves vagal nerve stimulation. VN stimulation is useful for technical problem solving, detecting non-recurrent laryngeal nerve (non-RLN), recognizing any recurrent laryngeal nerve (RLN) lesions, and precisely predicting RLN postoperative function. Herein, we present technical notes for the VN identification to achieve the critical view of safety of the VN stimulation with or without dissection. PMID:23860931

  15. Transcranial magnetic stimulation in neurology

    PubMed Central

    Eldaief, Mark C.; Press, Daniel Z.

    2013-01-01

    Summary Transcranial magnetic stimulation (TMS) is a neurophysiologic technique to noninvasively induce a controlled current pulse in a prespecified cortical target. This can be used to transiently disrupt the function of the targeted cortical region and explore causal relations to behavior, assess cortical reactivity, and map out functionally relevant brain regions, for example during presurgical assessments. Particularly when applied repetitively, TMS can modify cortical excitability and the effects can propagate trans-synaptically to interconnected cortical, subcortical, and spinal cord regions. As such, TMS can be used to assess the functional integrity of neural circuits and to modulate brain activity with potential therapeutic intent. PMID:24353923

  16. Intractable sacroiliac joint pain treated with peripheral nerve field stimulation

    PubMed Central

    Chakrabortty, Shushovan; Kumar, Sanjeev; Gupta, Deepak; Rudraraju, Sruthi

    2016-01-01

    As many as 62% low back pain patients can have sacroiliac joint (SIJ) pain. There is limited (to poor) evidence in regards to long-term pain relief with therapeutic intra-articular injections and/or conventional (heat or pulsed) radiofrequency ablations (RFAs) for SIJ pain. We report our pain-clinic experience with peripheral nerve field stimulation (PNFS) for two patients of intractable SIJ pain. They had reported absence of long-term pain relief (pain relief >50% for at least 2 weeks postinjection and at least 3 months post-RFA) with SIJ injections and SIJ RFAs. Two parallel permanent 8-contact subcutaneous stimulating leads were implanted under the skin overlying their painful SIJ. Adequate stimulation in the entire painful area was confirmed. For implantable pulse generator placement, a separate subcutaneous pocket was made in the upper buttock below the iliac crest level ipsilaterally. During the pain-clinic follow-up period, the patients had reduced their pain medications requirements by half with an additional report of more than 50% improvement in their functional status. The first patient passed away 2 years after the PNFS procedure due to medical causes unrelated to his chronic pain. The second patient has been comfortable with PNFS-induced analgesic regimen during her pain-clinic follow-up during last 5 years. In summary, PNFS can be an effective last resort option for SIJ pain wherein conventional interventional pain techniques have failed, and analgesic medication requirements are escalating or causing unwarranted side-effects.

  17. Chronic stability and selectivity of four-contact spiral nerve-cuff electrodes in stimulating the human femoral nerve

    NASA Astrophysics Data System (ADS)

    Fisher, L. E.; Tyler, D. J.; Anderson, J. S.; Triolo, R. J.

    2009-08-01

    This study describes the stability and selectivity of four-contact spiral nerve-cuff electrodes implanted bilaterally on distal branches of the femoral nerves of a human volunteer with spinal cord injury as part of a neuroprosthesis for standing and transfers. Stimulation charge threshold, the minimum charge required to elicit a visible muscle contraction, was consistent and low (mean threshold charge at 63 weeks post-implantation: 23.3 ± 8.5 nC) for all nerve-cuff electrode contacts over 63 weeks after implantation, indicating a stable interface with the peripheral nervous system. The ability of individual nerve-cuff electrode contacts to selectively stimulate separate components of the femoral nerve to activate individual heads of the quadriceps was assessed with fine-wire intramuscular electromyography while measuring isometric twitch knee extension moment. Six of eight electrode contacts could selectively activate one head of the quadriceps while selectively excluding others to produce maximum twitch responses of between 3.8 and 8.1 N m. The relationship between isometric twitch and tetanic knee extension moment was quantified, and selective twitch muscle responses scaled to between 15 and 35 N m in tetanic response to pulse trains with similar stimulation parameters. These results suggest that this nerve-cuff electrode can be an effective and chronically stable tool for selectively stimulating distal nerve branches in the lower extremities for neuroprosthetic applications.

  18. Effects of sciatic nerve stimulation on the propagation of cortical spreading depression

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoli; Yu, Zhidong; Zeng, Shaoqun; Luo, Qingming; Li, Pengcheng

    2008-02-01

    Cortical spreading depression (CSD) is an important pathological model of migraine and is related to other neural disorders, such as cerebral ischemia and epilepsy. It has been reported that brain stimulation is a quite effective way to treat neural diseases. However, direct stimulation could cause harm to brain. If peripheral nerve stimulation could have the same treatment, it would be essential to investigate the mechanisms of peripheral nerve and the study of sciatic nerve stimulation would have profound clinical meaning. In this paper, we used optical intrinsic signal imaging (OISI) and extracellular electrophysiologic recording techniques to study the effects of sciatic nerve stimulation on the propagation of CSD. We found that: (1) continuous sciatic nerve stimulation on rats caused a decrease in light intensity on the whole cortex, which meant an increase in cerebral blood volume(CBV); (2) the spreading velocity of CSD declined from 3.63+/- 0.272 mm/min to 3.06+/-0.260 mm/min during sciatic nerve stimulation, compared with that without sciatic nerve stimulation. In summary, data suggests that sciatic nerve stimulation elicits a response of cortex and causes a slowdown in the propagation of CSD.

  19. Electrical stimulation vs. pulsed and continuous-wave optical stimulation of the rat prostate cavernous nerves, in vivo

    NASA Astrophysics Data System (ADS)

    Perkins, William C.; Lagoda, Gwen A.; Burnett, Arthur; Fried, Nathaniel M.

    2015-07-01

    Identification and preservation of the cavernous nerves (CNs) during prostate cancer surgery is critical for post-operative sexual function. Electrical nerve stimulation (ENS) mapping has previously been tested as an intraoperative tool for CN identification, but was found to be unreliable. ENS is limited by the need for electrode-tissue contact, poor spatial precision from electrical current spreading, and stimulation artifacts interfering with detection. Alternatively, optical nerve stimulation (ONS) provides noncontact stimulation, improved spatial selectivity, and elimination of stimulation artifacts. This study compares ENS to pulsed/CW ONS to explore the ONS mechanism. A total of eighty stimulations were performed in 5 rats, in vivo. ENS (4 V, 5 ms, 10 Hz) was compared to ONS using a pulsed diode laser nerve stimulator (1873 nm, 5 ms, 10 Hz) or CW diode laser nerve stimulator (1455 nm). Intracavernous pressure (ICP) response and nerve compound action potentials (nCAPs) were measured. All three stimulation modes (ENS, ONS-CW, ONS-P) produced comparable ICP magnitudes. However, ENS demonstrated more rapid ICP response times and well defined nCAPs compared to unmeasurable nCAPs for ONS. Further experiments measuring single action potentials during ENS and ONS are warranted to further understand differences in the ENS and ONS mechanisms.

  20. Complications of vagal nerve stimulation for epilepsy in children.

    PubMed

    Rychlicki, F; Zamponi, N; Cesaroni, E; Corpaci, L; Trignani, R; Ducati, A; Scerrati, M

    2006-04-01

    Vagal nerve stimulation (VNS) is a surgical option to treat drug-resistant epilepsy. A few side effects have been described, mainly as anecdotal reports. We analysed our material concerning a juvenile population to identify the most common and most important complications, discussing them with the literature. Thirty-six patients were studied (18 months-18 years old). The children were assessed before the VNS implant and 3, 6, 12, 24 and 36 months after surgery. The mean follow-up was 30 months. Four patients required a second surgery: two for changing the device 3 years after implant; one for revision of an imperfect implant; one for removing a non-functioning device. In one patient a transient vocal cord paralysis was observed. Hoarseness was the main complaint (38.8%). More infrequent was mild sleep apnoea (8.3%), sternocleidomastoid muscle spasm, drooling and snoring in one patient each. Skin scars were reported with a different frequency according to the surgical technique. At variance with the literature reports, we did not observe infections. Side effects of VNS can be minimised, but not avoided completely, with a correct technical procedure, which in turn depends upon a thorough knowledge of vagus nerve anatomy.

  1. Transcutaneous electric nerve stimulation (TENS) in dentistry- A review

    PubMed Central

    Gupta, Aditi; Ladda, Ruchi; Kathariya, Mitesh; Saluja, Harish; Farooqui, Anjum-Ara

    2014-01-01

    Transcutaneous electric nerve stimulation (TENS) is a non-pharmacological method which is widely used by medical and paramedical professionals for the management of acute and chronic pain in a variety of conditions. Similarly, it can be utilized for the management of pain during various dental procedures as well as pain due to various conditions affecting maxillofacial region. This review aims to provide an insight into clinical research evidence available for the analgesic and non analgesic uses of TENS in pediatric as well as adult patients related to the field of dentistry. Also, an attempt is made to briefly discuss history of therapeutic electricity, mechanism of action of TENS, components of TENs equipment, types, techniques of administration, advantages and contradictions of TENS. With this we hope to raise awareness among dental fraternity regarding its dental applications thereby increasing its use in dentistry. Key words:Dentistry, pain, TENS. PMID:25674327

  2. Nerve growth factor: stimulation of polymorphonuclear leukocyte chemotaxis in vitro.

    PubMed Central

    Gee, A P; Boyle, M D; Munger, K L; Lawman, M J; Young, M

    1983-01-01

    Topical application of mouse nerve growth factor (NGF) to superficial skin wounds of mice has previously been shown to accelerate the rate of wound contraction. Results of the present study reveal that NGF in the presence of plasma is also chemotactic for human polymorphonuclear leukocytes in vitro, and the concentration of NGF required for this effect is similar to that which stimulates ganglionic neurite outgrowth. This property does not arise from liberation of the C5a fragment of complement, nor does it require the known enzymic activity of NGF. (NGF inactivated with diisopropyl fluorophosphate is equally active.) We conclude that NGF can display biological effects on cells of nonneural origin and function, and this feature might play a role in the early inflammatory response to injury. PMID:6580641

  3. Vagus nerve stimulation modulates visceral pain-related affective memory.

    PubMed

    Zhang, Xu; Cao, Bing; Yan, Ni; Liu, Jin; Wang, Jun; Tung, Vivian Oi Vian; Li, Ying

    2013-01-01

    Within a biopsychosocial model of pain, pain is seen as a conscious experience modulated by mental, emotional and sensory mechanisms. Recently, using a rodent visceral pain assay that combines the colorectal distension (CRD) model with the conditioned place avoidance (CPA) paradigms, we measured a learned behavior that directly reflects the affective component of visceral pain, and showed that perigenual anterior cingulate cortex (pACC) activation is critical for memory processing involved in long-term visceral affective state and prediction of aversive stimuli by contextual cue. Electrical vagus nerve stimulation (VNS) has become an established therapy for treatment-resistant epilepsy. VNS has also been shown to enhance memory performance in rats and humans. High-intensity VNS (400 μA) immediately following conditional training significantly increases the CRD-induced CPA scores, and enhanced the pain affective memory retention. In contrast, VNS (400 μA) had no effect on CPA induced by non-nociceptive aversive stimulus (U69,593). Low-intensity VNS (40 μA) had no effect on CRD-induced CPA. Electrophysiological recording showed that VNS (400 μA) had no effect on basal and CRD-induced ACC neuronal firing. Further, VNS did not alter CRD-induced visceral pain responses suggesting high intensity VNS facilitates visceral pain aversive memory independent of sensory discriminative aspects of visceral pain processing. The findings that vagus nerve stimulation facilities visceral pain-related affective memory underscore the importance of memory in visceral pain perception, and support the theory that postprandial factors may act on vagal afferents to modulate ongoing nature of visceral pain-induced affective disorder observed in the clinic, such as irritable bowel syndrome.

  4. Combined Spinal Cord Stimulation and Peripheral Nerve Stimulation for Brachial Plexopathy: A Case Report.

    PubMed

    Choi, Ji Hye; Choi, Shu Chung; Kim, Dong Kyu; Sung, Choon Ho; Chon, Jin Young; Hong, Sung Jin; Lee, Ji Young; Moon, Ho Sik

    2016-03-01

    Brachial plexopathy usually results from an iatrogenic brachial plexus injury and can sometimes cause severe chronic pain and disability. There are a number of possible treatments for this condition, including medication, physical therapy, nerve blocks, and neuromodulation, but they are not always successful. Recently, combined spinal cord stimulation (SCS) and peripheral nerve stimulation (PNS) have been tried for various chronic pain diseases because of their different mechanisms of action.Here, we describe the case of a 54-year-old man who was diagnosed with brachial plexopathy 8 years ago. He underwent video-assisted thoracoscopic surgery to remove a superior mediastinal mass. However, his brachial plexus was damaged during the surgery. Although he had received various treatments, the pain did not improve. For the management of intractable severe pain, he underwent SCS 2 years ago, which initially reduced his pain from numeric rating scale (NRS) 10/10 to NRS 4 - 5/10, but the pain then gradually increased, reaching NRS 8/10, 6 months ago. At that time, he was refractory to other treatments, and we therefore applied PNS in combination with SCS. The PNS electrode was positioned on the radial nerve under ultrasound guidance. After combined PNS and SCS, his background pain disappeared, although a breakthrough pain (NRS 3 - 4/10) was caused intermittently by light touch. Furthermore, the patient's need for analgesics decreased, and he was satisfied with the outcome of this combined treatment. We concluded that combined SCS and PNS is a very useful treatment modality, which can stimulate the target nerve both directly and indirectly, and hence, relieve pain from brachial plexopathy. PMID:27008302

  5. Changes in the frequency of swallowing during electrical stimulation of superior laryngeal nerve in rats.

    PubMed

    Tsuji, Kojun; Tsujimura, Takanori; Magara, Jin; Sakai, Shogo; Nakamura, Yuki; Inoue, Makoto

    2015-02-01

    The aim of the present study was to investigate the adaptation of the swallowing reflex in terms of reduced swallowing reflex initiation following continuous superior laryngeal nerve stimulation. Forty-four male Sprague Dawley rats were anesthetized with urethane. To identify swallowing, electromyographic activity of the left mylohyoid and thyrohyoid muscles was recorded. To evoke the swallowing response, the superior laryngeal nerve (SLN), recurrent laryngeal nerve, or cortical swallowing area was electrically stimulated. Repetitive swallowing evoked by continuous SLN stimulation was gradually reduced, and this reduction was dependent on the resting time duration between stimulations. Prior SLN stimulation also suppressed subsequent swallowing initiation. The reduction in evoked swallows induced by recurrent laryngeal nerve or cortical swallowing area stimulation was less than that following superior laryngeal nerve stimulation. Decerebration had no effect on the reduction in evoked swallows. Prior subthreshold stimulation reduced subsequent initiation of swallowing, suggesting that there was no relationship between swallowing movement evoked by prior stimulation and the subsequent reduction in swallowing initiation. Overall, these data suggest that reduced sensory afferent nerve firing and/or trans-synaptic responses, as well as part of the brainstem central pattern generator, are involved in adaptation of the swallowing reflex following continuous stimulation of swallow-inducing peripheral nerves and cortical areas.

  6. 21 CFR 882.5890 - Transcutaneous electrical nerve stimulator for pain relief.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... pain relief. 882.5890 Section 882.5890 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Devices § 882.5890 Transcutaneous electrical nerve stimulator for pain relief. (a) Identification. A transcutaneous electrical nerve stimulator for pain relief is a device used to apply an electrical current...

  7. 21 CFR 882.5890 - Transcutaneous electrical nerve stimulator for pain relief.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... pain relief. 882.5890 Section 882.5890 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Devices § 882.5890 Transcutaneous electrical nerve stimulator for pain relief. (a) Identification. A transcutaneous electrical nerve stimulator for pain relief is a device used to apply an electrical current...

  8. 21 CFR 882.5890 - Transcutaneous electrical nerve stimulator for pain relief.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... pain relief. 882.5890 Section 882.5890 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Devices § 882.5890 Transcutaneous electrical nerve stimulator for pain relief. (a) Identification. A transcutaneous electrical nerve stimulator for pain relief is a device used to apply an electrical current...

  9. 21 CFR 882.5890 - Transcutaneous electrical nerve stimulator for pain relief.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... pain relief. 882.5890 Section 882.5890 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Devices § 882.5890 Transcutaneous electrical nerve stimulator for pain relief. (a) Identification. A transcutaneous electrical nerve stimulator for pain relief is a device used to apply an electrical current...

  10. 21 CFR 882.5890 - Transcutaneous electrical nerve stimulator for pain relief.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... pain relief. 882.5890 Section 882.5890 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Devices § 882.5890 Transcutaneous electrical nerve stimulator for pain relief. (a) Identification. A transcutaneous electrical nerve stimulator for pain relief is a device used to apply an electrical current...

  11. 42 CFR 414.232 - Special payment rules for transcutaneous electrical nerve stimulators (TENS).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... nerve stimulators (TENS). 414.232 Section 414.232 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES... § 414.232 Special payment rules for transcutaneous electrical nerve stimulators (TENS). (a) General payment rule. Except as provided in paragraph (b) of this section, payment for TENS is made on a...

  12. 42 CFR 414.232 - Special payment rules for transcutaneous electrical nerve stimulators (TENS).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... nerve stimulators (TENS). 414.232 Section 414.232 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES... Special payment rules for transcutaneous electrical nerve stimulators (TENS). (a) General payment rule. Except as provided in paragraph (b) of this section, payment for TENS is made on a purchase basis...

  13. 42 CFR 414.232 - Special payment rules for transcutaneous electrical nerve stimulators (TENS).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... nerve stimulators (TENS). 414.232 Section 414.232 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES... Surgical Dressings § 414.232 Special payment rules for transcutaneous electrical nerve stimulators (TENS). (a) General payment rule. Except as provided in paragraph (b) of this section, payment for TENS...

  14. Quality of life and seizure outcome after vagus nerve stimulation in children with intractable epilepsy.

    PubMed

    Sherman, Elisabeth M S; Connolly, Mary B; Slick, Daniel J; Eyrl, Kim L; Steinbok, Paul; Farrell, Kevin

    2008-09-01

    This study examined the effect of vagus nerve stimulation on quality of life in children with epilepsy using a validated quality-of-life scale and an empirical technique that accounts for measurement error in assessing individual change (the reliable change index). Participants were 34 children with severe intractable epilepsy who underwent vagus nerve stimulation and 19 children with intractable epilepsy who received medical management. Parent-completed epilepsy-specific and global ratings at baseline and after 1 year indicated that most children had no changes in quality of life following vagus nerve stimulation (52%-77%), similar to the comparison group. There was a trend for decreases to be less common in the vagus nerve stimulation group (14% vs 37%, P < .07), but there was no relation between improved quality of life and seizure control. The results raise questions about the mechanisms that underlie changes in quality of life after vagus nerve stimulation in this group of children. PMID:18474931

  15. Improvement of physical performance by transcutaneous nerve stimulation in athletes.

    PubMed

    Kaada, B

    1984-01-01

    The present pilot study tested the exercise response to transcutaneous nerve stimulation (TNS) of 21 volunteers, who were well-trained competitive athletes. In 62 experiments (n) they received low-frequency TNS (2 Hz) for 30-45 min prior to either a road or track race, swimming race, bicycle ergometer exercise, isometric muscular endurance test, or dynamometer hand grip test. Improvement in performance compared with a corresponding number of control tests, without TNS or with placebo stimulation in the same subjects, was almost regularly observed in running, swimming and ergometer cycling, although with great individual variations. The average improvement was 4.3 sec (2.2%) in 1.000 m road racing (n = 9); 2.3 sec (1.8%) in 800 m track racing (n = 5); 0.9 sec (1.4%) in 100 m swimming (n = 12); 1.3 sec (0.8%) in 200 m swimming (n = 6); and 2.5 sec (0.9%) in 400 m swimming (n = 3). In a bicycle ergometer test with stepwise, progressive exercise to muscular fatigue, the maximal capacity was increased by 9% (n = 4). Local isometric muscle endurance of the elbow flexors (n = 7) and hand grip strengths (n = 11) were not significantly altered. Possible mechanisms involved in the response to TNS are discussed.

  16. The effects of general anaesthesia on nerve-motor response characteristics (rheobase and chronaxie) to peripheral nerve stimulation.

    PubMed

    Tsui, B C

    2014-04-01

    Using a simple surface nerve stimulation system, I examined the effects of general anaesthesia on rheobase (the minimum current required to stimulate nerve activity) and chronaxie (the minimum time for a stimulus twice the rheobase to elicit nerve activity). Nerve stimulation was used to elicit a motor response from the ulnar nerve at varying pulse widths before and after induction of general anaesthesia. Mean (SD) rheobase before and after general anaesthesia was 0.91 (0.37) mA (95% CI 0.77-1.04 mA) and 1.11 (0.53) mA (95% CI 0.92-1.30 mA), respectively. Mean (SD) chronaxie measured before and after general anaesthesia was 0.32 (0.17) ms (95% CI 0.26-0.38 ms) and 0.29 (0.13) ms (95% CI 0.24-0.33 ms), respectively. Under anaesthesia, rheobase values increased by an average of 20% (p = 0.05), but chronaxie values did not change significantly (p = 0.39). These results suggest that threshold currents used for motor response from nerve stimulation under general anaesthesia might be higher than those used in awake patients.

  17. Treating Obstructive Sleep Apnea with Hypoglossal Nerve Stimulation

    PubMed Central

    Eastwood, Peter R.; Barnes, Maree; Walsh, Jennifer H.; Maddison, Kathleen J.; Hee, Geoffrey; Schwartz, Alan R.; Smith, Philip L.; Malhotra, Atul; McEvoy, R. Douglas; Wheatley, John R.; O'Donoghue, Fergal J.; Rochford, Peter D.; Churchward, Tom; Campbell, Matthew C.; Palme, Carsten E.; Robinson, Sam; Goding, George S.; Eckert, Danny J.; Jordan, Amy S.; Catcheside, Peter G.; Tyler, Louise; Antic, Nick A.; Worsnop, Christopher J.; Kezirian, Eric J.; Hillman, David R.

    2011-01-01

    Background: Reduced upper airway muscle activity during sleep is fundamental to obstructive sleep apnea (OSA) pathogenesis. Hypoglossal nerve stimulation (HGNS) counteracts this problem, with potential to reduce OSA severity. Study Objectives: To examine safety and efficacy of a novel HGNS system (HGNS, Apnex Medical, Inc.) in treating OSA. Participants: Twenty-one patients, 67% male, age (mean ± SD) 53.6 ± 9.2 years, with moderate to severe OSA and unable to tolerate continuous positive airway pressure (CPAP). Design: Each participant underwent surgical implantation of the HGNS system in a prospective single-arm interventional trial. OSA severity was defined by apnea-hypopnea index (AHI) during in-laboratory polysomnography (PSG) at baseline and 3 and 6 months post-implant. Therapy compliance was assessed by nightly hours of use. Symptoms were assessed using the Epworth Sleepiness Scale (ESS), Functional Outcomes of Sleep Questionnaire (FOSQ), Calgary Sleep Apnea Quality of Life Index (SAQLI), and the Beck Depression Inventory (BDI). Results: HGNS was used on 89% ± 15% of nights (n = 21). On these nights, it was used for 5.8 ± 1.6 h per night. Nineteen of 21 participants had baseline and 6-month PSGs. There was a significant improvement (all P < 0.05) from baseline to 6 months in: AHI (43.1 ± 17.5 to 19.5 ± 16.7), ESS (12.1 ± 4.7 to 8.1 ± 4.4), FOSQ (14.4 ± 2.0 to 16.7 ± 2.2), SAQLI (3.2 ± 1.0 to 4.9 ± 1.3), and BDI (15.8 ± 9.0 to 9.7 ± 7.6). Two serious device-related adverse events occurred: an infection requiring device removal and a stimulation lead cuff dislodgement requiring replacement. Conclusions: HGNS demonstrated favorable safety, efficacy, and compliance. Participants experienced a significant decrease in OSA severity and OSA-associated symptoms. Clinical Trial Information: Name: Australian Clinical Study of the Apnex Medical HGNS System to Treat Obstructive Sleep Apnea. Registration Number: NCT01186926. URL: http://clinicaltrials.gov/ct2

  18. Artifacts produced during electrical stimulation of the vestibular nerve in cats. [autonomic nervous system components of motion sickness

    NASA Technical Reports Server (NTRS)

    Tang, P. C.

    1973-01-01

    Evidence is presented to indicate that evoked potentials in the recurrent laryngeal, the cervical sympathetic, and the phrenic nerve, commonly reported as being elicited by vestibular nerve stimulation, may be due to stimulation of structures other than the vestibular nerve. Experiments carried out in decerebrated cats indicated that stimulation of the petrous bone and not that of the vestibular nerve is responsible for the genesis of evoked potentials in the recurrent laryngeal and the cervical sympathetic nerves. The phrenic response to electrical stimulation applied through bipolar straight electrodes appears to be the result of stimulation of the facial nerve in the facial canal by current spread along the petrous bone, since stimulation of the suspended facial nerve evoked potentials only in the phrenic nerve and not in the recurrent laryngeal nerve. These findings indicate that autonomic components of motion sickness represent the secondary reactions and not the primary responses to vestibular stimulation.

  19. Tinnitus suppression by electric stimulation of the auditory nerve

    PubMed Central

    Chang, Janice E.; Zeng, Fan-Gang

    2012-01-01

    Electric stimulation of the auditory nerve via a cochlear implant (CI) has been observed to suppress tinnitus, but parameters of an effective electric stimulus remain unexplored. Here we used CI research processors to systematically vary pulse rate, electrode place, and current amplitude of electric stimuli, and measure their effects on tinnitus loudness and stimulus loudness as a function of stimulus duration. Thirteen tinnitus subjects who used CIs were tested, with nine (70%) being “Responders” who achieved greater than 30% tinnitus loudness reduction in response to at least one stimulation condition and the remaining four (30%) being “Non-Responders” who had less than 30% tinnitus loudness reduction in response to any stimulus condition tested. Despite large individual variability, several interesting observations were made between stimulation parameters, tinnitus characteristics, and tinnitus suppression. If a subject's tinnitus was suppressed by one stimulus, then it was more likely to be suppressed by another stimulus. If the tinnitus contained a “pulsating” component, then it would be more likely suppressed by a given combination of stimulus parameters than tinnitus without these components. There was also a disassociation between the subjects' clinical speech processor and our research processor in terms of their effectiveness in tinnitus suppression. Finally, an interesting dichotomy was observed between loudness adaptation to electric stimuli and their effects on tinnitus loudness, with the Responders exhibiting higher degrees of loudness adaptation than the Non-Responders. Although the mechanisms underlying these observations remain to be resolved, their clinical implications are clear. When using a CI to manage tinnitus, the clinical processor that is optimized for speech perception needs to be customized for optimal tinnitus suppression. PMID:22479238

  20. Intractable sacroiliac joint pain treated with peripheral nerve field stimulation.

    PubMed

    Chakrabortty, Shushovan; Kumar, Sanjeev; Gupta, Deepak; Rudraraju, Sruthi

    2016-01-01

    As many as 62% low back pain patients can have sacroiliac joint (SIJ) pain. There is limited (to poor) evidence in regards to long-term pain relief with therapeutic intra-articular injections and/or conventional (heat or pulsed) radiofrequency ablations (RFAs) for SIJ pain. We report our pain-clinic experience with peripheral nerve field stimulation (PNFS) for two patients of intractable SIJ pain. They had reported absence of long-term pain relief (pain relief >50% for at least 2 weeks postinjection and at least 3 months post-RFA) with SIJ injections and SIJ RFAs. Two parallel permanent 8-contact subcutaneous stimulating leads were implanted under the skin overlying their painful SIJ. Adequate stimulation in the entire painful area was confirmed. For implantable pulse generator placement, a separate subcutaneous pocket was made in the upper buttock below the iliac crest level ipsilaterally. During the pain-clinic follow-up period, the patients had reduced their pain medications requirements by half with an additional report of more than 50% improvement in their functional status. The first patient passed away 2 years after the PNFS procedure due to medical causes unrelated to his chronic pain. The second patient has been comfortable with PNFS-induced analgesic regimen during her pain-clinic follow-up during last 5 years. In summary, PNFS can be an effective last resort option for SIJ pain wherein conventional interventional pain techniques have failed, and analgesic medication requirements are escalating or causing unwarranted side-effects. PMID:27625495

  1. Intractable sacroiliac joint pain treated with peripheral nerve field stimulation

    PubMed Central

    Chakrabortty, Shushovan; Kumar, Sanjeev; Gupta, Deepak; Rudraraju, Sruthi

    2016-01-01

    As many as 62% low back pain patients can have sacroiliac joint (SIJ) pain. There is limited (to poor) evidence in regards to long-term pain relief with therapeutic intra-articular injections and/or conventional (heat or pulsed) radiofrequency ablations (RFAs) for SIJ pain. We report our pain-clinic experience with peripheral nerve field stimulation (PNFS) for two patients of intractable SIJ pain. They had reported absence of long-term pain relief (pain relief >50% for at least 2 weeks postinjection and at least 3 months post-RFA) with SIJ injections and SIJ RFAs. Two parallel permanent 8-contact subcutaneous stimulating leads were implanted under the skin overlying their painful SIJ. Adequate stimulation in the entire painful area was confirmed. For implantable pulse generator placement, a separate subcutaneous pocket was made in the upper buttock below the iliac crest level ipsilaterally. During the pain-clinic follow-up period, the patients had reduced their pain medications requirements by half with an additional report of more than 50% improvement in their functional status. The first patient passed away 2 years after the PNFS procedure due to medical causes unrelated to his chronic pain. The second patient has been comfortable with PNFS-induced analgesic regimen during her pain-clinic follow-up during last 5 years. In summary, PNFS can be an effective last resort option for SIJ pain wherein conventional interventional pain techniques have failed, and analgesic medication requirements are escalating or causing unwarranted side-effects. PMID:27625495

  2. Afferent vagal nerve stimulation resets baroreflex neural arc and inhibits sympathetic nerve activity

    PubMed Central

    Saku, Keita; Kishi, Takuya; Sakamoto, Kazuo; Hosokawa, Kazuya; Sakamoto, Takafumi; Murayama, Yoshinori; Kakino, Takamori; Ikeda, Masataka; Ide, Tomomi; Sunagawa, Kenji

    2014-01-01

    Abstract It has been established that vagal nerve stimulation (VNS) benefits patients and/or animals with heart failure. However, the impact of VNS on sympathetic nerve activity (SNA) remains unknown. In this study, we investigated how vagal afferent stimulation (AVNS) impacts baroreflex control of SNA. In 12 anesthetized Sprague–Dawley rats, we controlled the pressure in isolated bilateral carotid sinuses (CSP), and measured splanchnic SNA and arterial pressure (AP). Under a constant CSP, increasing the voltage of AVNS dose dependently decreased SNA and AP. The averaged maximal inhibition of SNA was ‐28.0 ± 10.3%. To evaluate the dynamic impacts of AVNS on SNA, we performed random AVNS using binary white noise sequences, and identified the transfer function from AVNS to SNA and that from SNA to AP. We also identified transfer functions of the native baroreflex from CSP to SNA (neural arc) and from SNA to AP (peripheral arc). The transfer function from AVNS to SNA strikingly resembled the baroreflex neural arc and the transfer functions of SNA to AP were indistinguishable whether we perturbed ANVS or CSP, indicating that they likely share common central and peripheral neural mechanisms. To examine the impact of AVNS on baroreflex, we changed CSP stepwise and measured SNA and AP responses with or without AVNS. AVNS resets the sigmoidal neural arc downward, but did not affect the linear peripheral arc. In conclusion, AVNS resets the baroreflex neural arc and induces sympathoinhibition in the same manner as the control of SNA and AP by the native baroreflex. PMID:25194023

  3. Noninvasive vagus nerve stimulation in the management of cluster headache: clinical evidence and practical experience

    PubMed Central

    Holle-Lee, Dagny; Gaul, Charly

    2016-01-01

    The efficacy of invasive vagal nerve stimulation as well as other invasive neuromodulatory approaches such as deep brain stimulation, occipital nerve stimulation, and ganglion sphenopalatine stimulation has been shown in the treatment of headache disorders in several studies in the past. However, these invasive treatment options were quite costly and often associated with perioperative and postoperative side effects, some severe. As such, they were predominantly restricted to chronic and therapy refractory patients. Transcutaneous vagal nerve stimulation now offers a new, noninvasive neuromodulatory treatment approach. Recently published studies showed encouraging results of noninvasive vagus nerve stimulation (nVNS), especially with respect to cluster headache, with high tolerability and a low rate of side effects; however, randomized controlled trials are needed to prove its efficacy. Further data also indicate therapeutic benefits regarding treatment of migraine and medication overuse headache. This review summarizes current knowledge and personal experiences of nVNS in the treatment of cluster headache. PMID:27134678

  4. Vagus Nerve Stimulation and Other Neuromodulation Methods for Treatment of Traumatic Brain Injury.

    PubMed

    Neren, Daniel; Johnson, Matthew D; Legon, Wynn; Bachour, Salam P; Ling, Geoffrey; Divani, Afshin A

    2016-04-01

    The objective of this paper is to review the current literature regarding the use of vagus nerve stimulation (VNS) in preclinical models of traumatic brain injury (TBI) as well as discuss the potential role of VNS along with alternative neuromodulation approaches in the treatment of human TBI. Data from previous studies have demonstrated VNS-mediated improvement following TBI in animal models. In these cases, VNS was observed to enhance motor and cognitive recovery, attenuate cerebral edema and inflammation, reduce blood brain barrier breakdown, and confer neuroprotective effects. Yet, the underlying mechanisms by which VNS enhances recovery following TBI remain to be fully elucidated. Several hypotheses have been offered including: a noradrenergic mechanism, reduction in post-TBI seizures and hyper-excitability, anti-inflammatory effects, attenuation of blood-brain barrier breakdown, and cerebral edema. We present other potential mechanisms by which VNS acts including enhancement of synaptic plasticity and recruitment of endogenous neural stem cells, stabilization of intracranial pressure, and interaction with the ghrelin system. In addition, alternative methods for the treatment of TBI including deep brain stimulation, transcranial magnetic stimulation, transcranial direct current stimulation, and focused ultrasound stimulation are discussed. Although the primary source data show that VNS improves TBI outcomes, it remains to be determined if these findings can be translated to clinical settings. PMID:26399249

  5. Vagus Nerve Stimulation and Other Neuromodulation Methods for Treatment of Traumatic Brain Injury.

    PubMed

    Neren, Daniel; Johnson, Matthew D; Legon, Wynn; Bachour, Salam P; Ling, Geoffrey; Divani, Afshin A

    2016-04-01

    The objective of this paper is to review the current literature regarding the use of vagus nerve stimulation (VNS) in preclinical models of traumatic brain injury (TBI) as well as discuss the potential role of VNS along with alternative neuromodulation approaches in the treatment of human TBI. Data from previous studies have demonstrated VNS-mediated improvement following TBI in animal models. In these cases, VNS was observed to enhance motor and cognitive recovery, attenuate cerebral edema and inflammation, reduce blood brain barrier breakdown, and confer neuroprotective effects. Yet, the underlying mechanisms by which VNS enhances recovery following TBI remain to be fully elucidated. Several hypotheses have been offered including: a noradrenergic mechanism, reduction in post-TBI seizures and hyper-excitability, anti-inflammatory effects, attenuation of blood-brain barrier breakdown, and cerebral edema. We present other potential mechanisms by which VNS acts including enhancement of synaptic plasticity and recruitment of endogenous neural stem cells, stabilization of intracranial pressure, and interaction with the ghrelin system. In addition, alternative methods for the treatment of TBI including deep brain stimulation, transcranial magnetic stimulation, transcranial direct current stimulation, and focused ultrasound stimulation are discussed. Although the primary source data show that VNS improves TBI outcomes, it remains to be determined if these findings can be translated to clinical settings.

  6. Electrical stimulation of dog pudendal nerve regulates the excitatory pudendal-to-bladder reflex

    PubMed Central

    Ju, Yan-he; Liao, Li-min

    2016-01-01

    Pudendal nerve plays an important role in urine storage and voiding. Our hypothesis is that a neuroprosthetic device placed in the pudendal nerve trunk can modulate bladder function after suprasacral spinal cord injury. We had confirmed the inhibitory pudendal-to-bladder reflex by stimulating either the branch or the trunk of the pudendal nerve. This study explored the excitatory pudendal-to-bladder reflex in beagle dogs, with intact or injured spinal cord, by electrical stimulation of the pudendal nerve trunk. The optimal stimulation frequency was approximately 15–25 Hz. This excitatory effect was dependent to some extent on the bladder volume. We conclude that stimulation of the pudendal nerve trunk is a promising method to modulate bladder function. PMID:27212934

  7. Variable spatial magnetic field influences peripheral nerves regeneration in rats.

    PubMed

    Suszyński, Krzysztof; Marcol, Wiesław; Szajkowski, Sebastian; Pietrucha-Dutczak, Marita; Cieślar, Grzegorz; Sieroń, Aleksander; Lewin-Kowalik, Joanna

    2014-09-01

    Generator of spatial magnetic field is one of most recent achievements among the magnetostimulators. This apparatus allows to obtain the rotating magnetic field. This new method may be more effective than other widely used techniques of magnetostimulation and magnetotherapy. We investigated the influence of alternating, spatial magnetic field on the regeneration of the crushed rat sciatic nerves. Functional and morphological evaluations were used. After crush injury of the right sciatic nerve, Wistar C rats (n = 80) were randomly divided into four groups (control and three experimental). The experimental groups (A, B, C) were exposed (20 min/day, 5 d/week, 4 weeks) to alternating spatial magnetic field of three different intensities. Sciatic Functional Index (SFI) and tensometric assessments were performed every week after nerve crush. Forty-eight hours before the sacrificing of animals, DiI (1,1'-di-octadecyl-3,3,3',3'-tetramethyloindocarbocyanine perchlorate) was applied 5 mm distally to the crush site. Collected nerves and dorsal root ganglia (DRG) were subjected to histological and immunohistochemical staining. The survival rate of DRG neurons was estimated. Regrowth and myelination of the nerves was examined. The results of SFI and tensometric assessment showed improvement in all experimental groups as compared to control, with best outcome observed in group C, exposed to the strongest magnetic field. In addition, DRG survival rate and nerve regeneration intensity were significantly higher in the C group. Above results indicate that strong spatial alternating magnetic field exerts positive effect on peripheral nerve regeneration and its application could be taken under consideration in the therapy of injured peripheral nerves. PMID:23781984

  8. Optimization of epilepsy treatment with vagus nerve stimulation

    NASA Astrophysics Data System (ADS)

    Uthman, Basim; Bewernitz, Michael; Liu, Chang-Chia; Ghacibeh, Georges

    2007-11-01

    Epilepsy is one of the most common chronic neurological disorders that affects close to 50 million people worldwide. Antiepilepsy drugs (AEDs), the main stay of epilepsy treatment, control seizures in two thirds of patients only. Other therapies include the ketogenic diet, ablative surgery, hormonal treatments and neurostimulation. While other approaches to stimulation of the brain are currently in the experimental phase vagus nerve stimulation (VNS) has been approved by the FDA since July 1997 for the adjunctive treatment of intractable partial onset epilepsy with and without secondary generalization in patients twelve years of age or older. The safety and efficacy of VNS have been proven and duplicated in two subsequent double-blinded controlled studies after two pilot studies demonstrated the feasibility of VNS in man. Long term observational studies confirmed the safety of VNS and that its effectiveness is sustained over time. While AEDs influence seizure thresholds via blockade or modulation of ionic channels, inhibit excitatory neurotransmitters or enhance inhibitory neurotransmitters the exact mechanism of action of VNS is not known. Neuroimaging studies revealed that VNS increases blood flow in certain regions of the brain such as the thalamus. Chemical lesions in the rat brains showed that norepinephrine is an important link in the anticonvulsant effect of VNS. Analysis of cerebrospinal fluid obtained from patients before and after treatment with VNS showed modest decreases in excitatory neurotransmitters. Although Hammond et al. reported no effect of VNS on scalp EEG by visual analysis and Salinsky et al. found no effect of VNS on scalp EEG by spectral analysis, Kuba et al. suggested that VNS reduces interictal epileptiform activity. Further, nonlinear dynamical analysis of the electroencephalogram in the rat and man have reportedly shown predictable changes (decrease in the short term Lyapunov exponent STLmax and T-index) more than an hour prior to the

  9. A method for estimation of stimulated brain sites based on columnar structure of cerebral cortex in transcranial magnetic stimulation

    NASA Astrophysics Data System (ADS)

    Hiwaki, Osamu; Inoue, Tomonori

    2009-04-01

    Transcranial magnetic stimulation (TMS) is a noninvasive method to stimulate the cortex. In TMS with a figure-of-eight coil, the induced electric field elicited by the pulsed magnetic fields is gathered beneath the center of the figure-of-eight coil, so the point on the cortex beneath the center of the figure-of-eight coil has been regarded as a stimulating site conventionally. However, the stimulating point determined in this way is not supposed to be plausible because electric field induced in TMS is dispersed over the brain vectorially. The present study proposed the novel method for the accurate estimation of stimulating points of the cortex in TMS. In our proposed method, the cortical structure and property of neural excitation in magnetic nerve stimulation were taken into account. The basic unit of the cerebral cortex is the cylindrical column containing pyramidal neurons perpendicular to the cortical surface, and neural excitation in the magnetic nerve stimulation is determined by the spatial derivative of the electric field parallel to the cablelike neuron such as a pyramidal neuron. According to these understandings, the relative intensity of nerve stimulation in TMS corresponds to the strength of the component of the induced electrical field perpendicular to the cortical surface. We realized the method for the estimation of stimulating sites of the cortex in TMS by using this principle. The component of the electric field perpendicular to the cortical surface at each pixel of magnetic resonance imaging was obtained with computation of the dot product of the electric field and the unit vector perpendicular to the cortex surface. The strength of the component of the electric field perpendicular to the cortical surface was regarded as the stimulating strength at each pixel of the cortical surface in TMS. We conducted the experiments of TMS to confirm the validity of this method. The cortex sites, which innervate muscles of the upper limb, were successfully

  10. Hypoglossal Nerve Stimulation Improves Obstructive Sleep Apnea: 12 Month Outcomes

    PubMed Central

    Kezirian, Eric J.; Goding, George S.; Malhotra, Atul; O'Donoghue, Fergal J.; Zammit, Gary; Wheatley, John R.; Catcheside, Peter G.; Smith, Philip L.; Schwartz, Alan R.; Walsh, Jennifer H.; Maddison, Kathleen J.; Claman, David M.; Huntley, Tod; Park, Steven Y.; Campbell, Matthew C.; Palme, Carsten E.; Iber, Conrad; Eastwood, Peter R.; Hillman, David R.; Barnes, Maree

    2013-01-01

    Reduced upper airway muscle activity during sleep is a key contributor to obstructive sleep apnoea (OSA) pathogenesis. Hypoglossal nerve stimulation (HGNS) activates upper airway dilator muscles, including the genioglossus, and has the potential to reduce OSA severity. The objective of this study was to examine the safety, feasibility, and efficacy of a novel HGNS system (HGNS®, Apnex Medical, Inc., St. Paul, MN) in treating OSA at 12 months following implantation. Thirty-one subjects (35% female, age 52·4±9·4 years) with moderate to severe OSA and unable to tolerate positive airway pressure underwent surgical implantation and activation of the HGNS system in a prospective single-arm interventional trial. Primary outcomes were changes in OSA severity (apnoea-hypopnoea index, AHI, from in-laboratory polysomnogram) and sleep-related quality of life (Functional Outcomes of Sleep Questionnaire, FOSQ). HGNS was used on 86±16% of nights for 5·4±1·4 hours per night. There was a significant improvement (p < 0·001) from baseline to 12 months in AHI (45.4±17·5 to 25·3±20·6 events/h) and FOSQ score (14·2±2·0 to 17·0±2·4) as well as other polysomnogram and symptom measures. Outcomes were stable compared to 6 months following implantation. Three serious device-related adverse events occurred: an infection requiring device removal and two stimulation lead cuff dislodgements requiring replacement. There were no significant adverse events with onset later than 6 months following implantation. HGNS demonstrated favourable safety, feasibility, and efficacy. PMID:24033656

  11. Transcutaneous electrical nerve stimulation (TENS) in angina pectoris.

    PubMed

    Mannheimer, C; Carlsson, C A; Vedin, A; Wilhelmsson, C

    1986-09-01

    The aim of this study was to determine the efficacy of transcutaneous electrical nerve stimulation (TENS) in the treatment of chronic stable severe angina pectoris. In a short-term study the effect of TENS was studied in 10 male patients with angina pectoris (functional class III and IV). All patients had previously been stabilized on long-term maximal oral treatment. The effects of the treatment were measured by means of repeated bicycle ergometer tests. All patients had an increased working capacity (16-85%), decreased ST segment depression and reduced recovery time during TENS. No adverse effects were observed. A long-term study of TENS on similarly selected patients showed beneficial effects in terms of pain reduction, reduced frequency of anginal attacks, increased physical activity and increased working capacity during bicycle ergometer tests. An invasive study was carried out with respect to systemic and coronary hemodynamics and myocardial metabolism during pacing provoked myocardial ischemia in 13 patients. The results showed that TENS led to an increased tolerance to pacing, improved lactate metabolism, less pronounced ST segment depression. A drop in systolic blood pressure during TENS treatment at identical pacing rates indicated a decreased afterload. An increased coronary flow to ischemic areas in the myocardium was supported by the fact that the rate pressure product during anginal pain increased during TENS.

  12. Transcranial Magnetic Stimulation for Schizophrenia.

    PubMed

    Dougall, Nadine; Maayan, Nicola; Soares-Weiser, Karla; McDermott, Lisa M; McIntosh, Andrew

    2015-11-01

    People with schizophrenia typically experience auditory hallucinations or delusions during acute episodes. Although effective drug treatments are available, many have intractable symptoms that do not recover between acute episodes. One proposed alternative to drug treatments is transcranial magnetic stimulation (TMS). To date, many research trials to assess effectiveness of TMS for people with symptoms of schizophrenia have been conducted worldwide. However, there is a lack of consensus on whether TMS should be recommended to be adopted in routine clinical practice. We conducted a systematic review of the literature for all relevant randomized controlled trials (RCTs) comparing TMS with sham or standard treatment. Forty-one trials (1473 participants) survived eligibility criteria and had extractable data. We found significant differences in favor of temporoparietal TMS compared with sham TMS for global state (7 RCTs, n = 224, MD: -0.5, 95% CI: -0.76 to -0.23) and for positive symptoms measured on the Positive and Negative Syndrome Scale (5 RCTs, n = 127, MD: -6.09, 95% CI: -10.95 to -1.22). However, we also found that the quality of trial reporting was frequently suboptimal and the risks of bias were strong or unascertainable for many trial aspects; this led to many results being graded as very low-quality evidence. On that basis, we were unable to definitively support or refute the routine use of TMS in clinical practice. Future definitive trials of TMS with rigorous processes and high-quality reporting are needed.

  13. Insulation discontinuity in a vagus nerve stimulator lead: a treatable cause of intolerable stimulation-related symptoms.

    PubMed

    Spitz, Mark C; Winston, Ken R; Maa, Edward H; Ojemann, Steven G

    2010-04-01

    Discontinuity in the silicone insulation over an electrode of a left vagus nerve stimulator (VNS) allowed the aberrant leak of current to the phrenic nerve and other structures. This resulted in ipsilateral diaphragmatic dysfunction, inability to vocalize, and severe radiating pain into the jaw and upper incisor for the duration of each stimulation. The device was explanted and a new device was implanted. All stimulation-related symptoms ceased immediately. A similar discontinuity in the silicone insulation is the likely explanation for several prior reports of poorly understood pains and phrenic nerve stimulation in patients with VNSs. The findings and analysis of this case establish a rationale for consideration of replacement of the VNS lead in all similarly symptomatic patients.

  14. Risk of Encountering Dorsal Scapular and Long Thoracic Nerves during Ultrasound-guided Interscalene Brachial Plexus Block with Nerve Stimulator

    PubMed Central

    Kim, Yeon Dong; Yu, Jae Yong; Shim, Junho; Heo, Hyun Joo

    2016-01-01

    Background Recently, ultrasound has been commonly used. Ultrasound-guided interscalene brachial plexus block (IBPB) by posterior approach is more commonly used because anterior approach has been reported to have the risk of phrenic nerve injury. However, posterior approach also has the risk of causing nerve injury because there are risks of encountering dorsal scapular nerve (DSN) and long thoracic nerve (LTN). Therefore, the aim of this study was to evaluate the risk of encountering DSN and LTN during ultrasound-guided IBPB by posterior approach. Methods A total of 70 patients who were scheduled for shoulder surgery were enrolled in this study. After deciding insertion site with ultrasound, awake ultrasound-guided IBPB with nerve stimulator by posterior approach was performed. Incidence of muscle twitches (rhomboids, levator scapulae, and serratus anterior muscles) and current intensity immediately before muscle twitches disappeared were recorded. Results Of the total 70 cases, DSN was encountered in 44 cases (62.8%) and LTN was encountered in 15 cases (21.4%). Both nerves were encountered in 10 cases (14.3%). Neither was encountered in 21 cases (30.4%). The average current measured immediately before the disappearance of muscle twitches was 0.44 mA and 0.50 mA at DSN and LTN, respectively. Conclusions Physicians should be cautious on the risk of injury related to the anatomical structures of nerves, including DSN and LTN, during ultrasound-guided IBPB by posterior approach. Nerve stimulator could be another option for a safer intervention. Moreover, if there is a motor response, it is recommended to select another way to secure better safety. PMID:27413483

  15. Magnetic fields in noninvasive brain stimulation.

    PubMed

    Vidal-Dourado, Marcos; Conforto, Adriana Bastos; Caboclo, Luis Otávio Sales Ferreira; Scaff, Milberto; Guilhoto, Laura Maria de Figueiredo Ferreira; Yacubian, Elza Márcia Targas

    2014-04-01

    The idea that magnetic fields could be used therapeutically arose 2000 years ago. These therapeutic possibilities were expanded after the discovery of electromagnetic induction by the Englishman Michael Faraday and the American Joseph Henry. In 1896, Arsène d'Arsonval reported his experience with noninvasive brain magnetic stimulation to the scientific French community. In the second half of the 20th century, changing magnetic fields emerged as a noninvasive tool to study the nervous system and to modulate neural function. In 1985, Barker, Jalinous, and Freeston presented transcranial magnetic stimulation, a relatively focal and painless technique. Transcranial magnetic stimulation has been proposed as a clinical neurophysiology tool and as a potential adjuvant treatment for psychiatric and neurologic conditions. This article aims to contextualize the progress of use of magnetic fields in the history of neuroscience and medical sciences, until 1985. PMID:23787954

  16. Magnetic fields in noninvasive brain stimulation.

    PubMed

    Vidal-Dourado, Marcos; Conforto, Adriana Bastos; Caboclo, Luis Otávio Sales Ferreira; Scaff, Milberto; Guilhoto, Laura Maria de Figueiredo Ferreira; Yacubian, Elza Márcia Targas

    2014-04-01

    The idea that magnetic fields could be used therapeutically arose 2000 years ago. These therapeutic possibilities were expanded after the discovery of electromagnetic induction by the Englishman Michael Faraday and the American Joseph Henry. In 1896, Arsène d'Arsonval reported his experience with noninvasive brain magnetic stimulation to the scientific French community. In the second half of the 20th century, changing magnetic fields emerged as a noninvasive tool to study the nervous system and to modulate neural function. In 1985, Barker, Jalinous, and Freeston presented transcranial magnetic stimulation, a relatively focal and painless technique. Transcranial magnetic stimulation has been proposed as a clinical neurophysiology tool and as a potential adjuvant treatment for psychiatric and neurologic conditions. This article aims to contextualize the progress of use of magnetic fields in the history of neuroscience and medical sciences, until 1985.

  17. Spectral and spatial dependence of
diffuse optical signals in response to
peripheral nerve stimulation

    PubMed Central

    Chen, Debbie K.; Erb, M. Kelley; Tong, Yunjie; Yu, Yang; Sassaroli, Angelo; Bergethon, Peter R.; Fantini, Sergio

    2010-01-01

    Using non-invasive, near-infrared spectroscopy we have previously reported optical signals measured at or around peripheral nerves in response to their stimulation. Such optical signals featured amplitudes on the order of 0.1% and peaked about 100 ms after peripheral nerve stimulation in human subjects. Here, we report a study of the spatial and spectral dependence of the optical signals induced by stimulation of the human median and sural nerves, and observe that these optical signals are: (1) unlikely due to either dilation or constriction of blood vessels, (2) not associated with capillary bed hemoglobin, (3) likely due to blood vessel(s) displacement, and (4) unlikely due to fiber-skin optical coupling effects. We conclude that the most probable origin of the optical response to peripheral nerve stimulation is from displacement of blood vessels within the optically probed volume, as a result of muscle twitch in adjacent areas. PMID:21258519

  18. Signal space separation algorithm and its application on suppressing artifacts caused by vagus nerve stimulation for magnetoencephalography recordings.

    PubMed

    Song, Tao; Cui, Li; Gaa, Kathleen; Feffer, Lori; Taulu, Samu; Lee, Roland R; Huang, Mingxiong

    2009-12-01

    Magnetoencephalography (MEG) has been successfully applied to presurgical epilepsy foci localization and brain functional mapping. Because the neuronal magnetic signals from the brain are extremely weak, MEG measurement requires both low environment noise and the subject/patient being free of artifact-generating metal objects. This strict requirement makes it hard for patients with vagus nerve stimulator, or other similar medical devices, to benefit from the presurgical MEG examinations. Therefore, an approach that can effectively reduce the environmental noise and faithfully recover the brain signals is highly desirable. We applied spatiotemporal signal space separation method, an advanced signal processing approach that can recover bio-magnetic signal from inside the MEG sensor helmet and suppress external disturbance from outside the helmet in empirical MEG measurements, on MEG recordings from normal control subjects and patients who has vagus nerve stimulator. The original MEG recordings were heavily contaminated, and the data could not be assessed. After applying temporal signal space separation, the strong external artifacts from outside the brain were successfully removed, and the neuronal signal from the human brain was faithfully recovered. Both of the goodness-of-fit and 95% confident limit volume confirmed the significant improvement after temporal signal space separation. Hence, temporal signal space separation makes presurgical MEG examinations possible for patients with implanted vagus nerve stimulator or similar medical devices.

  19. Transcranial magnetic stimulation and the human brain

    NASA Astrophysics Data System (ADS)

    Hallett, Mark

    2000-07-01

    Transcranial magnetic stimulation (TMS) is rapidly developing as a powerful, non-invasive tool for studying the human brain. A pulsed magnetic field creates current flow in the brain and can temporarily excite or inhibit specific areas. TMS of motor cortex can produce a muscle twitch or block movement; TMS of occipital cortex can produce visual phosphenes or scotomas. TMS can also alter the functioning of the brain beyond the time of stimulation, offering potential for therapy.

  20. Bladder contractions alter inspiratory termination by superior laryngeal and intercostal nerve stimulation.

    PubMed

    Bartlett, D; Knuth, S L

    1999-08-01

    Gradual distension of the urinary bladder evokes spontaneous bladder contractions (SBCs), which are associated with reduced inspiratory activity in the phrenic and other inspiratory motor nerves. We examined the influence of isovolumetric SBCs on the threshold for termination of phrenic inspiration by electrical stimulation of superior laryngeal and/or mid-thoracic intercostal nerves (ICN) in decerebrate, vagotomized, paralyzed, ventilated cats. Although SBCs reduced phrenic inspiratory activity, the threshold for inspiratory termination by nerve stimulation was increased. The results emphasize the complexity of the synaptic connections among brain stem neurons governing micturition and breathing.

  1. Responses of nerve fibres of the rat saphenous nerve neuroma to mechanical and chemical stimulation: an in vitro study

    PubMed Central

    Rivera, Luis; Gallar, Juana; Pozo, Miguel Angel; Belmonte, Carlos

    2000-01-01

    The response of neuroma nerve endings to different stimuli was studied in a saphenous nerve neuroma preparation in vitro. Electrical activity was recorded from 141 single fibres dissected of saphenous nerve. One-third (27 %) displayed spontaneous activity. Based on their response to mechanical and chemical stimuli, neuroma nerve fibres were classified as mechanosensory fibres (47.5 %), mechanically insensitive chemosensory fibres (17.0 %), polymodal nociceptor fibres (28.4 %) and unresponsive fibres (7.1 %). Mechanosensory and polymodal neuroma endings responded to von Frey hair stimulation either with a few impulses (phasic units) or a sustained discharge (tonic units). Polymodal units were additionally activated by at least one of the following stimuli: acidic solutions; a combination of bradykinin, prostaglandin E2, serotonin, substance P and histamine (all at 1 μM) plus 7 mm KCl (inflammatory soup); 600 mm NaCl and capsaicin. Low pH solutions increased the firing discharge of polymodal endings proportionally to the proton concentration. The ‘inflammatory soup’ evoked a firing response characterized by the absence of tachyphylaxis, which appeared when its components were applied separately. Both stimuli sensitized polymodal fibres to mechanical stimulation. Hypertonic NaCl (600 mm) and capsaicin (3.3 mm) induced a prolonged discharge that outlasted the stimulus duration. Mechanically insensitive chemosensory neuroma fibres exhibited responses to chemical stimuli analogous to polymodal fibres. They became mechanically sensitive after chemical stimulation. These findings show that neuroma nerve endings in the rat saphenous nerve neuroma in vitro are functionally heterogeneous and exhibit properties reminiscent of those in intact mechanosensory, polymodal and ‘silent’ nociceptor sensory afferents, including their sensitization by algesic chemicals. PMID:10970431

  2. A model of the stimulation of a nerve fiber by electromagnetic induction.

    PubMed

    Roth, B J; Basser, P J

    1990-06-01

    A model is presented to explain the physics of nerve stimulation by electromagnetic induction. Maxwell's equations predict the induced electric field distribution that is produced when a capacitor is discharged through a stimulating coil. A nonlinear Hodgkin-Huxley cable model describes the response of the nerve fiber to this induced electric field. Once the coil's position, orientation, and shape are given and the resistance, capacitance, and initial voltage of the stimulating circuit are specified, this model predicts the resulting transmembrane potential of the fiber as a function of distance and time. It is shown that the nerve fiber is stimulated by the gradient of the component of the induced electric field that is parallel to the fiber, which hyperpolarizes or depolarizes the membrane and may stimulate an action potential. Finally, it predicts complicated dynamics such as action potential annihilation and dispersion.

  3. Electrical stimulation of the hypoglossal nerve in the treatment of obstructive sleep apnea.

    PubMed

    Kezirian, Eric J; Boudewyns, An; Eisele, David W; Schwartz, Alan R; Smith, Philip L; Van de Heyning, Paul H; De Backer, Wilfried A

    2010-10-01

    Upper airway occlusion in obstructive sleep apnea has been attributed to a decline in pharyngeal neuromuscular activity occurring in a structurally narrowed airway. Surgical treatment focuses on the correction of anatomic abnormalities, but there is a potential role for activation of the upper airway musculature, especially with stimulation of the hypoglossal nerve and genioglossus muscle. We present evidence from research on upper airway neuromuscular electrical stimulation in animals and humans. We also present results from eight obstructive sleep apnea patients with a fully implanted system for hypoglossal nerve stimulation, demonstrating an improvement in upper airway collapsibility and obstructive sleep apnea severity. Future research, including optimization of device features and stimulation parameters as well as patient selection, is necessary to make hypoglossal nerve stimulation a viable alternative to positive airway pressure therapy and upper airway surgical procedures.

  4. Temperature-controlled optical stimulation of the rat prostate cavernous nerves

    NASA Astrophysics Data System (ADS)

    Tozburun, Serhat; Hutchens, Thomas C.; McClain, Michael A.; Lagoda, Gwen A.; Burnett, Arthur L.; Fried, Nathaniel M.

    2013-06-01

    Optical nerve stimulation (ONS) may be useful as a diagnostic tool for intraoperative identification and preservation of the prostate cavernous nerves (CN), responsible for erectile function, during prostate cancer surgery. Successful ONS requires elevating the nerve temperature to within a narrow range (˜42 to 47°C) for nerve activation without thermal damage to the nerve. This preliminary study explores a prototype temperature-controlled optical nerve stimulation (TC-ONS) system for maintaining a constant (±1°C) nerve temperature during short-term ONS of the rat prostate CNs. A 150-mW, 1455-nm diode laser was operated in continuous-wave mode, with and without temperature control, during stimulation of the rat CNs for 15 to 30 s through a fiber optic probe with a 1-mm-diameter spot. A microcontroller opened and closed an in-line mechanical shutter in response to an infrared sensor, with a predetermined temperature set point. With TC-ONS, higher laser power settings were used to rapidly and safely elevate the CNs to a temperature necessary for a fast intracavernous pressure response, while also preventing excessive temperatures that would otherwise cause thermal damage to the nerve. With further development, TC-ONS may provide a rapid, stable, and safe method for intraoperative identification and preservation of the prostate CNs.

  5. Electrical potentials from the eye and optic nerve of Strombus: effects of electrical stimulation of the optic nerve.

    PubMed

    Gillary, H L

    1977-02-01

    1. Photic stimulation of the mature eye of Strombus can evoke in the optic nerve 'on' activity in numerous small afferent fibres and repetitive 'off' bursts of afferent impulses in a smaller number of larger fibres. 2. Synchronous invasion of the eye by electrically evoked impulses in small optic nerve fibres (apparently the 'on' afferents, antidromically activated) can evoke a burst of impulses in the larger 'off' fibres which propagate away from the eye. Invasion of the eye via one branch of optic nerve can evoke an answering burst in another branch. 3. Such electrically evoked bursts are similar to light-evoked 'off' bursts with respect to their impulse composition, their ability to be inhibited by illumination of the eye, and their susceptibility to MgCl2 anaesthesia. 4. Invasion of the eye by a train of repetitive electrically evoked impulses in the absence of photic stimulation can give rise to repetitive 'off' bursts as well as concomitant oscillatory potentials in the eye which are similar to those normally evoked by cessation of a photic stimulus. 5. The electrically evoked 'off' bursts appear to be caused by an excitatory rebound following the cessation of inhibitory synaptic input from photoreceptors which can be antidromically activated by electrical stimulation of the optic nerve. 6. The experimental results suggest that the rhythmic discharge of the 'off' fibres evoked by the cessation of a photic stimulus is mediated by the abrupt decrease of inhibitory synaptic input from the receptors. PMID:192827

  6. Chronic migraine headache prevention with noninvasive vagus nerve stimulation

    PubMed Central

    Calhoun, Anne H.; Lipton, Richard B.; Grosberg, Brian M.; Cady, Roger K.; Dorlas, Stefanie; Simmons, Kristy A.; Mullin, Chris; Liebler, Eric J.; Goadsby, Peter J.; Saper, Joel R.

    2016-01-01

    Objective: To evaluate the feasibility, safety, and tolerability of noninvasive vagus nerve stimulation (nVNS) for the prevention of chronic migraine (CM) attacks. Methods: In this first prospective, multicenter, double-blind, sham-controlled pilot study of nVNS in CM prophylaxis, adults with CM (≥15 headache d/mo) entered the baseline phase (1 month) and were subsequently randomized to nVNS or sham treatment (2 months) before receiving open-label nVNS treatment (6 months). The primary endpoints were safety and tolerability. Efficacy endpoints in the intent-to-treat population included change in the number of headache days per 28 days and acute medication use. Results: Fifty-nine participants (mean age, 39.2 years; mean headache frequency, 21.5 d/mo) were enrolled. During the randomized phase, tolerability was similar for nVNS (n = 30) and sham treatment (n = 29). Most adverse events were mild/moderate and transient. Mean changes in the number of headache days were −1.4 (nVNS) and −0.2 (sham) (Δ = 1.2; p = 0.56). Twenty-seven participants completed the open-label phase. For the 15 completers initially assigned to nVNS, the mean change from baseline in headache days after 8 months of treatment was −7.9 (95% confidence interval −11.9 to −3.8; p < 0.01). Conclusions: Therapy with nVNS was well-tolerated with no safety issues. Persistent prophylactic use may reduce the number of headache days in CM; larger sham-controlled studies are needed. ClinicalTrials.gov identifier: NCT01667250. Classification of evidence: This study provides Class II evidence that for patients with CM, nVNS is safe, is well-tolerated, and did not significantly change the number of headache days. This pilot study lacked the precision to exclude important safety issues or benefits of nVNS. PMID:27412146

  7. Hyperinsulinemia Potentiates Airway Responsiveness to Parasympathetic Nerve Stimulation in Obese Rats

    PubMed Central

    Jacoby, David B.; Fryer, Allison D.

    2014-01-01

    Obesity is a substantial risk factor for developing asthma, but the molecular mechanisms underlying this relationship are unclear. We tested the role of insulin in airway responsiveness to nerve stimulation using rats genetically prone or resistant to diet-induced obesity. Airway response to vagus nerve stimulation and airway M2 and M3 muscarinic receptor function were measured in obese-prone and -resistant rats with high or low circulating insulin. The effects of insulin on nerve-mediated human airway smooth muscle contraction and human M2 muscarinic receptor function were tested in vitro. Our data show that increased vagally mediated bronchoconstriction in obesity is associated with hyperinsulinemia and loss of inhibitory M2 muscarinic receptor function on parasympathetic nerves. Obesity did not induce airway inflammation or increase airway wall thickness. Smooth muscle contraction to acetylcholine was not increased, indicating that hyperresponsiveness is mediated at the level of airway nerves. Reducing serum insulin with streptozotocin protected neuronal M2 receptor function and prevented airway hyperresponsiveness to vagus nerve stimulation in obese rats. Replacing insulin restored dysfunction of neuronal M2 receptors and airway hyperresponsiveness to vagus nerve stimulation in streptozotocin-treated obese rats. Treatment with insulin caused loss of M2 receptor function, resulting in airway hyperresponsiveness to vagus nerve stimulation in obese-resistant rats, and inhibited human neuronal M2 receptor function in vitro. This study shows that it is not obesity per se but hyperinsulinemia accompanying obesity that potentiates vagally induced bronchoconstriction by inhibiting neuronal M2 muscarinic receptors and increasing acetylcholine release from airway parasympathetic nerves. PMID:24605871

  8. Laryngeal and tracheal afferent nerve stimulation evokes swallowing in anaesthetized guinea pigs.

    PubMed

    Tsujimura, Takanori; Udemgba, Chioma; Inoue, Makoto; Canning, Brendan J

    2013-09-15

      We describe swallowing reflexes evoked by laryngeal and tracheal vagal afferent nerve stimulation in anaesthetized guinea pigs. The swallowing reflexes evoked by laryngeal citric acid challenges were abolished by recurrent laryngeal nerve (RLN) transection and mimicked by electrical stimulation of the central cut ends of an RLN. By contrast, the number of swallows evoked by upper airway/pharyngeal distensions was not significantly reduced by RLN transection but they were virtually abolished by superior laryngeal nerve transection. Laryngeal citric acid-evoked swallowing was mimicked by laryngeal capsaicin challenges, implicating transient receptor potential vanilloid 1 (TRPV1)-expressing laryngeal afferent nerves arising from the jugular ganglia. The swallowing evoked by citric acid and capsaicin and evoked by electrical stimulation of either the tracheal or the laryngeal mucosa occurred at stimulation intensities that were typically subthreshold for evoking cough in these animals. Swallowing evoked by airway afferent nerve stimulation also desensitized at a much slower rate than cough. We speculate that swallowing is an essential component of airway protection from aspiration associated with laryngeal and tracheal afferent nerve activation. PMID:23858010

  9. Dilation of the oropharynx via selective stimulation of the hypoglossal nerve

    NASA Astrophysics Data System (ADS)

    Huang, Jingtao; Sahin, Mesut; Durand, Dominique M.

    2005-12-01

    The functional effects of selective hypoglossal nerve (HG) stimulation with a multi-contact peripheral nerve electrode were assessed using images of the upper airways and the tongue in anesthetized beagles. A biphasic pulse train of 50 Hz frequency and 2 s duration was applied through each one of the tripolar contact sets of the nerve electrode while the pharyngeal images were acquired into a computer. The stimulation current was limited to 20% above the activation threshold for maximum selectivity. The images showed that various contact sets could generate several different activation patterns of the tongue muscles resulting in medial and/or lateral dilation and closing of the airways at the tongue root. Some of these patterns translated into an increase in the oropharyngeal size while others did not have any effect. The pharyngeal sizes were not statistically different during stimulation either between the two different positions of the head (30° and 60°), or when the lateral contacts were compared with the medial ones. The contacts that had the least effect generated an average of 53 ± 15% pharyngeal dilation relative to the best contacts, indicating that the results are marginally sensitive to the contact position around the HG nerve trunk. These results suggest that selective HG nerve stimulation can be a useful technique to produce multiple tongue activation patterns that can dilate the pharynx. This may in turn increase the size of the patient population who can benefit from HG nerve stimulation as a treatment method for obstructive sleep apnea.

  10. Dilation of the oropharynx via selective stimulation of the hypoglossal nerve.

    PubMed

    Huang, Jingtao; Sahin, Mesut; Durand, Dominique M

    2005-12-01

    The functional effects of selective hypoglossal nerve (HG) stimulation with a multi-contact peripheral nerve electrode were assessed using images of the upper airways and the tongue in anesthetized beagles. A biphasic pulse train of 50 Hz frequency and 2 s duration was applied through each one of the tripolar contact sets of the nerve electrode while the pharyngeal images were acquired into a computer. The stimulation current was limited to 20% above the activation threshold for maximum selectivity. The images showed that various contact sets could generate several different activation patterns of the tongue muscles resulting in medial and/or lateral dilation and closing of the airways at the tongue root. Some of these patterns translated into an increase in the oropharyngeal size while others did not have any effect. The pharyngeal sizes were not statistically different during stimulation either between the two different positions of the head (30 degrees and 60 degrees), or when the lateral contacts were compared with the medial ones. The contacts that had the least effect generated an average of 53 +/- 15% pharyngeal dilation relative to the best contacts, indicating that the results are marginally sensitive to the contact position around the HG nerve trunk. These results suggest that selective HG nerve stimulation can be a useful technique to produce multiple tongue activation patterns that can dilate the pharynx. This may in turn increase the size of the patient population who can benefit from HG nerve stimulation as a treatment method for obstructive sleep apnea. PMID:16317230

  11. Does Pulsed Magnetic Field Therapy Influence Nerve Regeneration in the Median Nerve Model of the Rat?

    PubMed Central

    Beck-Broichsitter, Benedicta E.; Lamia, Androniki; Fregnan, Federica; Smeets, Ralf; Becker, Stephan T.; Sinis, Nektarios

    2014-01-01

    The aim of this study was to evaluate the impact of pulsed magnetic field therapy on peripheral nerve regeneration after median nerve injury and primary coaptation in the rat. Both median nerves were surgically exposed and denervated in 24 female Wistar rats. A microsurgical coaptation was performed on the right side, whereas on the left side a spontaneous healing was prevented. The study group underwent a daily pulsed magnetic field therapy; the other group served as a control group. The grasping force was recorded 2 weeks after the surgical intervention for a period of 12 weeks. The right median nerve was excised and histologically examined. The histomorphometric data and the functional assessments were analyzed by t-test statistics and one-way ANOVA. One-way ANOVA indicated a statistically significant influence of group affiliation and grasping force (P = 0.0078). Grasping strength was higher on a significant level in the experimental group compared to the control group permanently from the 9th week to the end of the study. T-test statistics revealed a significantly higher weight of the flexor digitorum sublimis muscle (P = 0.0385) in the experimental group. The histological evaluation did not reveal any statistically significant differences concerning the histomorphometric parameters. Our results suggest that the pulsed magnetic field therapy has a positive influence on the functional aspects of neural regeneration. More studies are needed to precisely evaluate and optimize the intensity and duration of the application. PMID:25143937

  12. Magnetic stimulation of marigold seed

    NASA Astrophysics Data System (ADS)

    Afzal, I.; Mukhtar, K.; Qasim, M.; Basra, S. M. A.; Shahid, M.; Haq, Z.

    2012-10-01

    The effects of magnetic field treatments of French marigold seeds on germination, early seedling growth and biochemical changes of seedlings were studied under controlled conditions. For this purpose, seeds were exposed to five different magnetic seed treatments for 3 min each. Most of seed treatments resulted in improved germination speed and spread, root and shoot length, seed soluble sugars and a-amylase activity. Magnetic seed treatment with 100 mT maximally improved germination, seedling vigour and starch metabolism as compared to control and other seed treatments. In emergence experiment, higher emergence percentage (4-fold), emergence index (5-fold) and vigorous seedling growth were obtained in seeds treated with 100 mT. Overall, the enhancement of marigold seeds by magnetic seed treatment with 100 mT could be related to enhanced starch metabolism. The results suggest that magnetic field treatments of French marigold seeds have the potential to enhance germination, early growth and biochemical parameters of seedlings.

  13. A stimulating nerve cuff for chronic in vivo measurements of torque produced about the ankle in the mouse.

    PubMed

    Warren, G L; Ingalls, C P; Armstrong, R B

    1998-06-01

    Specific muscle training and chronic contractile measurements are difficult in rodents, especially in the mouse. The primary reason for this is the lack of a means for stimulating the motor nerve that does not damage the nerve and that permits reproducible measurements of contractility. In this paper, we describe procedures for the construction and implantation of a stimulating nerve cuff for use on the mouse common peroneal nerve. We demonstrate that nerve cuff implantation success rates can be high (i.e., 75-93%), as determined from measurements of maximal isometric torque produced by the anterior crural muscles. Isometric torque production is not adversely affected by the nerve cuff because the torque produced matches that observed in our established percutaneous stimulation model. We also demonstrate that use of the nerve cuff for stimulation is compatible with electromyographic measurements made on the tibialis anterior muscle, with no sign of stimulation artifact in the electromyographic signal. PMID:9609814

  14. Peripheral Nerve Stimulation for Treatment of Post-Amputation Pain – A Case Report

    PubMed Central

    Rauck, Richard L.; Kapural, Leonardo; Cohen, Steven P.; North, James M.; Gilmore, Christopher A.; Zang, Rosemary H.; Boggs, Joseph W.

    2012-01-01

    Many amputees suffer from post-amputation pain, which can be extremely debilitating, decrease quality of life, increase the risk of depression, and negatively affect interpersonal relationships and the ability to work. Present methods of treatment, including medications, are often unsatisfactory in reducing post-amputation pain. Electrical stimulation of the nerve innervating the painful area could reduce the pain, but peripheral nerve stimulation is rarely used to treat post-amputation pain because present methods require invasive surgical access and precise placement of the leads in close proximity (≤ 2 mm) with the nerve. The present study investigated a novel approach to peripheral nerve stimulation in which a lead was placed percutaneously a remote distance (> 1 cm) away from the femoral nerve in a patient with severe residual limb pain 33 years following a below-knee amputation. Electrical stimulation generated ≥ 75% paresthesia coverage, reduced residual limb pain by > 60%, and improved quality of life outcomes as measured by the pain interference scale of the Brief Pain Inventory-Short Form (100% reduction in pain interference), Pain Disability Index (74% reduction in disability), and the Patient Global Impression of Change (Very Much Improved) during a 2-week home trial. There were no adverse events. The ability to generate significant paresthesia coverage and pain relief with a single lead inserted percutaneously and remotely from the target nerve holds promise for providing relief of post-amputation pain. PMID:22548686

  15. Minimizing Stimulus Current in a Wearable Pudendal Nerve Stimulator Using Computational Models.

    PubMed

    Shiraz, Arsam N; Craggs, Michael; Leaker, Brian; Demosthenous, Andreas

    2016-04-01

    After spinal cord injury, functions of the lower urinary tract may be disrupted. A wearable device with surface electrodes which can effectively control the bladder functions would be highly beneficial to the patients. A trans-rectal pudendal nerve stimulator may provide such a solution. However, the major limiting factor in such a stimulator is the high level of current it requires to recruit the nerve fibers. Also, the variability of the trajectory of the nerve in different individuals should be considered. Using computational models and an approximate trajectory of the nerve derived from an MRI study, it is demonstrated in this paper that it may be possible to considerably reduce the required current levels for trans-rectal stimulation of the pudendal nerve compared to the values previously reported in the literature. This was corroborated by considering an ensemble of possible and probable variations of the trajectory. The outcome of this study suggests that trans-rectal stimulation of the pudendal nerve is a plausible long term solution for treating lower urinary tract dysfunctions after spinal cord injury. PMID:26415182

  16. Electrochemical and Electrophysiological Performance of Platinum Electrodes Within the Ninety-Nine-Electrode Stimulating Nerve Cuff.

    PubMed

    Pečlin, Polona; Mehle, Andraž; Karpe, Blaž; Rozman, Janez

    2015-10-01

    The trend in neural prostheses using selective nerve stimulation for electrical stimulation therapies is headed toward single-part systems having a large number of working electrodes (WEs), each of which selectively stimulate neural tissue or record neural response (NR). The present article reviews the electrochemical and electrophysiological performance of platinum WE within a ninety-nine-electrode spiral cuff for selective nerve stimulation and recording of peripheral nerves, with a focus on the vagus nerve (VN). The electrochemical properties of the WE were studied in vitro using the electrochemical impedance spectroscopy (EIS) technique. The equivalent circuit model (ECM) of the interface between the WE and neural tissue was extracted from the EIS data and simulated in the time domain using a preset current stimulus. Electrophysiological performance of in-space and fiber-type highly selective vagus nerve stimulation (VNS) was tested using an isolated segment of a porcine VN and carotid artery as a reference. A quasitrapezoidal current-controlled pulse (stimulus) was applied to the VN or arterial segment using an appointed group of three electrodes (triplet). The triplet and stimulus were configured to predominantly stimulate B-fibers and minimize the stimulation of A-fibers. The EIS results revealed capacitive charge transfer predominance, which is a highly desirable property. Electrophysiological performance testing indicated the potential existence of certain parameters and waveforms of the stimulus for which the contribution of the A-fibers to the NR decreased slightly and that of the B-fibers increased slightly. Findings show that the design of the stimulating electrodes, based on the EIS and ECM results, could act as a useful tool for nerve cuff development.

  17. Deep Brain Stimulation using Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Jiles, David; Williams, Paul; Crowther, Lawrence; Iowa State University Team; Wolfson CentreMagnetics Team

    2011-03-01

    New applications for transcranial magnetic stimulation are developing rapidly for both diagnostic and therapeutic purposes. Therefore so is the demand for improved performance, particularly in terms of their ability to stimulate deeper regions of the brain and to do so selectively. The coil designs that are used presently are limited in their ability to stimulate the brain at depth and with high spatial focality. Consequently, any improvement in coil performance would have a significant impact in extending the usefulness of TMS in both clinical applications and academic research studies. New and improved coil designs have then been developed, modeled and tested as a result of this work. A large magnetizing coil, 300mm in diameter and compatible with a commercial TMS system has been constructed to determine its feasibility for use as a deep brain stimulator. The results of this work have suggested directions that could be pursued in order to further improve the coil designs.

  18. Electrical stimulation accelerates axonal and functional peripheral nerve regeneration across long gaps.

    PubMed

    Haastert-Talini, Kirsten; Schmitte, Ruth; Korte, Nele; Klode, Dorothee; Ratzka, Andreas; Grothe, Claudia

    2011-04-01

    Short-term low-frequency electrical stimulation (ESTIM) of proximal peripheral nerve stumps prior to end-to-end coaptation or tubular bridging of small distances has been reported to increase preferential motor reinnervation and functional motor recovery in animal models and human patients undergoing carpal tunnel release surgery. We investigated the effects of ESTIM on regeneration across rat sciatic nerve gaps, which exceed distances that allow spontaneous regeneration. Three different reconstruction approaches were combined with ESTIM in the experimental groups. Nerve gaps (13 mm) were bridged using (I) nerve autotransplantation, (II) transplantation of differentially filled silicone tubes, or (III) transplantation of tubular grafts containing fibroblast growth factor-2 overexpressing Schwann cells (SCs) for gene therapy. The regeneration outcome was followed for up to 8 weeks, and functionally as well as histomorphometrically analyzed in comparison to non-stimulated control groups. Combining ESTIM with nerve autotransplantation significantly increased the nerve fiber density in the regenerated nerve, and the grade of functional recovery as detected by electrodiagnostic recordings from the gastrocnemius muscle. The combination of ESTIM with transplantation of naïve SCs increased the regeneration of gap-bridging nerve tissue. Although macroscopic tissue regeneration was not further improved after combining ESTIM with FGF-2(21/23-kD) gene therapy, the latter resulted in a high rate of regenerated nerves that functionally reconnected to the target muscle. Based on our results, brief ESTIM shows high potential to accelerate axonal as well as functional (motor and sensory) outcomes in the clinical setting of peripheral nerve gap reconstruction in human patients. PMID:21265597

  19. Electrophysiologic studies of cervical vagus nerve stimulation in humans: II. Evoked potentials.

    PubMed

    Hammond, E J; Uthman, B M; Reid, S A; Wilder, B J

    1992-01-01

    Evidence from studies of experimental animals indicates that electrical stimulation of the vagus nerve not only can alter the EEG but evokes activity in specific brain areas. We report effects of electrical stimulation of the vagus nerve in 9 patients with medically intractable seizures as part of a clinical trial of chronic vagal stimulation for control of epilepsy. The left vagus nerve in the neck was stimulated with a programmable implanted stimulator. Effects of stimulus amplitude, duration, and rate were studied. Noncephalic reference recording of the vagus nerve evoked potential showed some unusual properties: a scalp negative component occurred with a latency of 12 ms, very high amplitude (< or = 60 microV), and widespread scalp distribution. Field distribution studies indicated that this potential was myogenic in origin and generated in the region of the stimulating electrodes in the neck area. Chemically induced muscle paralysis confirmed this observation. Bipolar scalp recording showed several small-amplitude topographically distinct potentials occurring in 30 ms. No effect, either acute or chronic, could be detected on pattern-reversal evoked potentials, auditory brainstem evoked potentials, auditory 40-Hz potentials, or cognitive evoked potentials. PMID:1464258

  20. Stimulation of raphe (obscurus) nucleus causes long-term potentiation of phrenic nerve activity in cat.

    PubMed

    Millhorn, D E

    1986-12-01

    1. The respiratory response, measured as integrated phrenic nerve activity, during and for up to an hour following 10 min of continuous electrical stimulation of raphe obscurus was quantitated in anaesthetized, artificially ventilated cats whose carotid sinus nerves and vagus nerves had been cut. End-tidal PCO2 and body temperature were kept constant with servocontrollers. 2. Stimulation of raphe obscurus caused a significant increase in both phrenic tidal activity and respiratory frequency that persisted following cessation of the stimulus. This persistent facilitation is referred to as 'long-term potentiation' of respiration. 3. Control stimulations in the parenchyma of the medulla oblongata failed to stimulate respiration and cause the long-term potentiation. 4. Both the direct facilitatory effects of raphe obscurus stimulation on phrenic nerve activity and the long-term potentiation of respiration following the stimulus were prevented by pre-treating cats with methysergide, a serotonin receptor antagonist. 5. The results are discussed in terms of the raphe obscurus being the potential source of the long-term potentiation of respiration that occurs following stimulation of carotid body afferents (Millhorn, Eldridge & Waldrop, 1980a, b). PMID:3114470

  1. Numerical dosimetry of transcranial magnetic stimulation coils

    NASA Astrophysics Data System (ADS)

    Crowther, Lawrence; Hadimani, Ravi; Jiles, David

    2014-03-01

    Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation technique capable of stimulating neurons by means of electromagnetic induction. TMS can be used to map brain function and shows promise for the diagnosis and treatment of neurological and psychiatric disorders. Calculation of fields induced in the brain are necessary to accurately identify stimulated neural tissue during TMS. This allows the development of novel TMS coil designs capable of stimulating deeper brain regions and increasing the localization of stimulation that can be achieved. We have performed numerical calculations of magnetic and electric field with high-resolution anatomically realistic human head models to find these stimulated brain regions for a variety of proposed TMS coil designs. The realistic head models contain heterogeneous tissue structures and electrical conductivities, yielding superior results to those obtained from the simplified homogeneous head models that are commonly employed. The attenuation of electric field as a function of depth in the brain and the localization of stimulating field have been methodically investigated. In addition to providing a quantitative comparison of different TMS coil designs the variation of induced field between subjects has been investigated. We also show the differences in induced fields between adult, adolescent and child head models to preemptively identify potential safety issues in the application of pediatric TMS.

  2. [ELECTRIC STIMULATION OF VAGUS NERVE MODULATES A PROPAGATION OF OXYGEN EPILEPSY IN RABBITS].

    PubMed

    Zhilyaev, S Yu; Moskvin, A N; Platonova, T F; Demchenko, I T

    2015-11-01

    The activation of autonomic afferents (achieved through the vagus nerve (VN) electrical stimulation) on CNS O2 toxicity and cardiovascular function was investigated. In conscious rabbits at 5 ATA 02, prodromal signs of CNS O2 toxicity and convulsion latency were determined with and without vagus nerve (VN) stimulation. EEG, ECG and respiration were also recorded. In rabbits at 5 ATA, sympathetic overdrive and specific patterns on the EEG (synchronization of slow-waves), ECG (tachycardia) and respiration (respiratory minute volume increase) preceded motor convulsions. Vagus nerve stimulation increased parasympathetic component of autonomic drive and significantly delayed prodromal signs of oxygen toxicity and convulsion latency. Autonomic afferent input to the brain is a novel target for preventing CNS toxicity in HBO2. PMID:26995956

  3. Pharyngeal patency caused by stimulation of the hypoglossal nerve in anaesthesia-relaxed patients.

    PubMed

    Ilomäki, J; Baer, G A; Karhuketo, T; Talonen, P; Puhakka, H

    1997-01-01

    Impaired function of the genioglossal muscle is the most frequent reason for upper airway obstruction during sleep. Functional electrical stimulation (FES) of the hypoglossal nerve may be used to push the tongue forward to release the obstruction. Anaesthesia-induced upper airway obstruction resembles the situation during obstructive sleep apnea (OSA) syndrome. In order to develop an implantable FES system for treatment of OSA, we stimulated the exposed hypoglossal nerve in 6 patients undergoing radical cancer surgery of the head and neck region. Tongue movements during stimulation were video filmed and the amount of unobstructed airway achieved with stimulation was estimated using the adjacent intubation tube as reference. In every case, stimulation created an unobstructed airway, larger than the intubation tube.

  4. Application of conductive polymers, scaffolds and electrical stimulation for nerve tissue engineering.

    PubMed

    Ghasemi-Mobarakeh, Laleh; Prabhakaran, Molamma P; Morshed, Mohammad; Nasr-Esfahani, Mohammad Hossein; Baharvand, Hossein; Kiani, Sahar; Al-Deyab, Salem S; Ramakrishna, Seeram

    2011-04-01

    Among the numerous attempts to integrate tissue engineering concepts into strategies to repair nearly all parts of the body, neuronal repair stands out. This is partially due to the complexity of the nervous anatomical system, its functioning and the inefficiency of conventional repair approaches, which are based on single components of either biomaterials or cells alone. Electrical stimulation has been shown to enhance the nerve regeneration process and this consequently makes the use of electrically conductive polymers very attractive for the construction of scaffolds for nerve tissue engineering. In this review, by taking into consideration the electrical properties of nerve cells and the effect of electrical stimulation on nerve cells, we discuss the most commonly utilized conductive polymers, polypyrrole (PPy) and polyaniline (PANI), along with their design and modifications, thus making them suitable scaffolds for nerve tissue engineering. Other electrospun, composite, conductive scaffolds, such as PANI/gelatin and PPy/poly(ε-caprolactone), with or without electrical stimulation, are also discussed. Different procedures of electrical stimulation which have been used in tissue engineering, with examples on their specific applications in tissue engineering, are also discussed.

  5. Design of a compact laparoscopic probe for optical stimulation of the cavernous nerves

    NASA Astrophysics Data System (ADS)

    Tozburun, Serhat; Fried, Nathaniel M.

    2009-02-01

    The cavernous nerves are responsible for erectile function and course along the prostate surface, varying in size and location among patients, making preservation of sexual function challenging after prostate cancer surgery. Electrical stimulation has proven inconsistent and unreliable in identifying these nerves and evaluating nerve function. Optical stimulation of the rat cavernous nerves has recently been reported as a alternative to electrical stimulation, with potential advantages including noncontact stimulation and improved spatial selectivity. This study describes the design of a compact laparoscopic probe for future clinical use in optical nerve stimulation. The 10-Fr (3.4-mm-OD) prototype laparoscopic probe includes an aspheric lens for collimation of the laser beam with a 0.8- mm-diameter spot, coupled with a 200-μm-core optical fiber. A 45° gold-coated rod mirror in the probe tip provides side-firing delivery of the laser radiation. The probe handle houses a miniature linear motorized stage for lateral scanning of the probe tip over a 25-mm line along the prostate surface. A 5.5-W Thulium fiber laser with tunable wavelength range of 1850-1880 nm was tested with the probe. The probe fits through a standard 5-mm-ID laparoscopic port and is capable of delivering pulse energies up to 8 mJ (1.6 J/cm2) at a 2.5-ms pulse duration, well above the threshold (~ 0.35 J/cm2) for optical stimulation of the cavernous nerves.

  6. Magnetic Stimulation Studies of Foveal Representation

    ERIC Educational Resources Information Center

    Lavidor, Michal; Walsh, Vincent

    2004-01-01

    The right and left visual fields each project to the contralateral cerebral hemispheres, but the extent of the functional overlap of the two hemifields along the vertical meridian is still under debate. After presenting the spatial, temporal, and functional specifications of Transcranial Magnetic Stimulation (TMS), we show that TMS is particularly…

  7. Magnetized stimulated scattering in pulsar winds

    NASA Technical Reports Server (NTRS)

    Sincell, Mark W.; Krolik, Julian H.

    1992-01-01

    The effects of stimulated scattering on a collimated high brightness temperature beam of photons traversing a relativistically streaming magnetized plasma are studied. Under the assumption that the center of the photon beam is parallel to the bulk motion, we calculate the scattering rate as a function of the angular spread of the beam and the Lorentz factor gamma. Magnetization changes the photon recoil, without which stimulated scattering has no effect. It also introduces a strong dependence on frequency and polarization: if the photon frequency matches the electron cyclotron frequency, the scattering rate of photons polarized perpendicular to the magnetic field can be substantially enhanced relative to Thomson, and if the photon frequency is much less than the cyclotron frequency, the scattering is suppressed. Applying these calculations to pulsars, we find that stimulated scattering of the radio beam in the magnetized wind believed to exist outside the light cylinder can substantially alter the spectrum and polarization state of the radio signal. We suggest that the scattering rate is so high in some pulsars that the ability of the radio signal to penetrate the pulsar magnetosphere requires modification of either the conventional model of the magnetosphere or assumptions about the effects of stimulated scattering upon a beam.

  8. Effects of acute selective pudendal nerve electrical stimulation after simulated childbirth injury

    PubMed Central

    Gill, Bradley C.; Dissaranan, Charuspong; Zutshi, Massarat; Balog, Brian M.; Lin, Danli; Damaser, Margot S.

    2013-01-01

    During childbirth, a combinatorial injury occurs and can result in stress urinary incontinence (SUI). Simulated childbirth injury, consisting of vaginal distension (VD) and pudendal nerve crush (PNC), results in slowed recovery of continence, as well as decreased expression of brain-derived neurotrophic factor (BDNF), a regenerative cytokine. Electrical stimulation has been shown to upregulate BDNF in motor neurons and facilitate axon regrowth through the increase of βII-tubulin expression after injury. In this study, female rats underwent selective pudendal nerve motor branch (PNMB) stimulation after simulated childbirth injury or sham injury to determine whether such stimulation affects bladder and anal function after injury and whether the stimulation increases BDNF expression in Onuf's nucleus after injury. Rats received 4 h of VD followed by bilateral PNC and 1 h of subthreshold electrical stimulation of the left PNMB and sham stimulation of the right PNMB. Rats underwent filling cystometry and anal pressure recording before, during, and after the stimulation. Bladder and anal contractile function were partially disrupted after injury. PNMB stimulation temporarily inhibited bladder contraction after injury. Two days and 1 wk after injury, BDNF expression in Onuf's nucleus of the stimulated side was significantly increased compared with the sham-stimulated side, whereas βII-tubulin expression in Onuf's nucleus of the stimulated side was significantly increased only 1 wk after injury. Acute electrical stimulation of the pudendal nerve proximal to the crush site upregulates BDNF and βII-tubulin in Onuf's nucleus after simulated childbirth injury, which could be a potential preventive option for SUI after childbirth injury. PMID:23152293

  9. Transcranial magnetic stimulation reduces nociceptive threshold in rats.

    PubMed

    Ambriz-Tututi, Mónica; Sánchez-González, Violeta; Drucker-Colín, René

    2012-05-01

    Transcranial magnetic stimulation (TMS) is a procedure that uses magnetic fields to stimulate or inhibit nerve cells in the brain noninvasively. TMS induces an electromagnetic current in the underlying cortical neurons. Varying frequencies and intensities of TMS increase or decrease excitability in the cortical area directly targeted. It has been suggested that TMS has potential in the treatment of some neurological disorders such as Parkinson's disease, stroke, and depression. Initial case reports and open label trials reported by several groups support the use of TMS in pain treatment. In the present study, we evaluated the effect of TMS on the nociceptive threshold in the rat. The parameters used were a frequency of 60 Hz and an intensity of 2 and 6 mT for 2 hr twice per day. After 5 days of TMS treatment, rats were evaluated for mechanical, chemical, and cold stimulation. We observed a significant reduction in the nociceptive threshold in TMS-treated rats but not in sham-treated rats in all behavioral tests evaluated. When TMS treatment was stopped, a slow recovery to normal mechanic threshold was observed. Interestingly, i.c.v. MK-801 or CNQX administration reverted the TMS-induced pronociception. The results suggest that high-frequency TMS can alter the nociceptive threshold and produce allodynia in the rats; results suggest the involvement of NMDA and AMPA/KA receptors on TMS-induced allodynia in the rat. PMID:22315163

  10. Blood pressure control with selective vagal nerve stimulation and minimal side effects

    NASA Astrophysics Data System (ADS)

    Plachta, Dennis T. T.; Gierthmuehlen, Mortimer; Cota, Oscar; Espinosa, Nayeli; Boeser, Fabian; Herrera, Taliana C.; Stieglitz, Thomas; Zentner, Joseph

    2014-06-01

    Objective. Hypertension is the largest threat to patient health and a burden to health care systems. Despite various options, 30% of patients do not respond sufficiently to medical treatment. Mechanoreceptors in the aortic arch relay blood pressure (BP) levels through vagal nerve (VN) fibers to the brainstem and trigger the baroreflex, lowering the BP. Selective electrical stimulation of these nerve fibers reduced BP in rats. However, there is no technique described to localize and stimulate these fibers inside the VN without inadvertent stimulation of non-baroreceptive fibers causing side effects like bradycardia and bradypnea. Approach. We present a novel method for selective VN stimulation to reduce BP without the aforementioned side effects. Baroreceptor compound activity of rat VN (n = 5) was localized using a multichannel cuff electrode, true tripolar recording and a coherent averaging algorithm triggered by BP or electrocardiogram. Main results. Tripolar stimulation over electrodes near the barofibers reduced the BP without triggering significant bradycardia and bradypnea. The BP drop was adjusted to 60% of the initial value by varying the stimulation pulse width and duration, and lasted up to five times longer than the stimulation. Significance. The presented method is robust to impedance changes, independent of the electrode's relative position, does not compromise the nerve and can run on implantable, ultra-low power signal processors.

  11. Model-based analysis and design of nerve cuff electrodes for restoring bladder function by selective stimulation of the pudendal nerve

    NASA Astrophysics Data System (ADS)

    Kent, Alexander R.; Grill, Warren M.

    2013-06-01

    Objective. Electrical stimulation of the pudendal nerve (PN) is being developed as a means to restore bladder function in persons with spinal cord injury. A single nerve cuff electrode placed on the proximal PN trunk may enable selective stimulation of distinct fascicles to maintain continence or evoke micturition. The objective of this study was to design a nerve cuff that enabled selective stimulation of the PN. Approach. We evaluated the performance of both flat interface nerve electrode (FINE) cuff and round cuff designs, with a range of FINE cuff heights and number of contacts, as well as multiple contact orientations. This analysis was performed using a computational model, in which the nerve and fascicle cross-sectional positions from five human PN trunks were systematically reshaped within the nerve cuff. These cross-sections were used to create finite element models, with electric potentials calculated and applied to a cable model of a myelinated axon to evaluate stimulation selectivity for different PN targets. Subsequently, the model was coupled to a genetic algorithm (GA) to identify solutions that used multiple contact activation to maximize selectivity and minimize total stimulation voltage. Main results. Simulations did not identify any significant differences in selectivity between FINE and round cuffs, although the latter required smaller stimulation voltages for target activation due to preserved localization of targeted fascicle groups. Further, it was found that a ten contact nerve cuff generated sufficient selectivity for all PN targets, with the degree of selectivity dependent on the relative position of the target within the nerve. The GA identified solutions that increased fitness by 0.7-45.5% over single contact activation by decreasing stimulation of non-targeted fascicles. Significance. This study suggests that using an optimal nerve cuff design and multiple contact activation could enable selective stimulation of the human PN trunk for

  12. Assessing the Firing Properties of the Electrically Stimulated Auditory Nerve Using a Convolution Model.

    PubMed

    Strahl, Stefan B; Ramekers, Dyan; Nagelkerke, Marjolijn M B; Schwarz, Konrad E; Spitzer, Philipp; Klis, Sjaak F L; Grolman, Wilko; Versnel, Huib

    2016-01-01

    The electrically evoked compound action potential (eCAP) is a routinely performed measure of the auditory nerve in cochlear implant users. Using a convolution model of the eCAP, additional information about the neural firing properties can be obtained, which may provide relevant information about the health of the auditory nerve. In this study, guinea pigs with various degrees of nerve degeneration were used to directly relate firing properties to nerve histology. The same convolution model was applied on human eCAPs to examine similarities and ultimately to examine its clinical applicability. For most eCAPs, the estimated nerve firing probability was bimodal and could be parameterised by two Gaussian distributions with an average latency difference of 0.4 ms. The ratio of the scaling factors of the late and early component increased with neural degeneration in the guinea pig. This ratio decreased with stimulation intensity in humans. The latency of the early component decreased with neural degeneration in the guinea pig. Indirectly, this was observed in humans as well, assuming that the cochlear base exhibits more neural degeneration than the apex. Differences between guinea pigs and humans were observed, among other parameters, in the width of the early component: very robust in guinea pig, and dependent on stimulation intensity and cochlear region in humans. We conclude that the deconvolution of the eCAP is a valuable addition to existing analyses, in particular as it reveals two separate firing components in the auditory nerve. PMID:27080655

  13. Assessing the Firing Properties of the Electrically Stimulated Auditory Nerve Using a Convolution Model.

    PubMed

    Strahl, Stefan B; Ramekers, Dyan; Nagelkerke, Marjolijn M B; Schwarz, Konrad E; Spitzer, Philipp; Klis, Sjaak F L; Grolman, Wilko; Versnel, Huib

    2016-01-01

    The electrically evoked compound action potential (eCAP) is a routinely performed measure of the auditory nerve in cochlear implant users. Using a convolution model of the eCAP, additional information about the neural firing properties can be obtained, which may provide relevant information about the health of the auditory nerve. In this study, guinea pigs with various degrees of nerve degeneration were used to directly relate firing properties to nerve histology. The same convolution model was applied on human eCAPs to examine similarities and ultimately to examine its clinical applicability. For most eCAPs, the estimated nerve firing probability was bimodal and could be parameterised by two Gaussian distributions with an average latency difference of 0.4 ms. The ratio of the scaling factors of the late and early component increased with neural degeneration in the guinea pig. This ratio decreased with stimulation intensity in humans. The latency of the early component decreased with neural degeneration in the guinea pig. Indirectly, this was observed in humans as well, assuming that the cochlear base exhibits more neural degeneration than the apex. Differences between guinea pigs and humans were observed, among other parameters, in the width of the early component: very robust in guinea pig, and dependent on stimulation intensity and cochlear region in humans. We conclude that the deconvolution of the eCAP is a valuable addition to existing analyses, in particular as it reveals two separate firing components in the auditory nerve.

  14. Pulsed 808-nm infrared laser stimulation of the auditory nerve in guinea pig cochlea.

    PubMed

    Xia, Nan; Wu, Xiao Y; Wang, Xing; Mou, Zong X; Wang, Man Q; Gu, Xin; Zheng, Xiao L; Hou, Wen S

    2014-01-01

    Pulsed near-infrared radiation has been proposed as an alternative stimulus for auditory nerve stimulation and could be potentially used in the design of cochlear implant. Although the infrared with high absorption coefficient of water (i.e., wavelength ranged from 1.8 to 2.2 μm) has been widely investigated, the lymph in the cochlea absorbs most of the infrared energies, and only a small part can arrive at the target auditory nerves. The present study is aimed to test whether the short-wavelength near-infrared irradiation with lower absorption coefficients can penetrate the lymph fluid to stimulate the auditory nerves. An 808-nm near-infrared laser was chosen to stimulate the auditory nerve in the guinea pig cochlea. The infrared pulse was delivered by an optical fiber that was surgically inserted near the round window membrane and oriented toward the spiral ganglion cells in the basal turn of the cochlea. The 2-Hz infrared pulses were used to stimulate the cochlea before and after the deafness with different pulse durations (100-1,000 μs). Optically evoked compound action potentials (oCAPs) were recorded during the infrared radiation. We successfully recorded oCAPs from both normal hearing animals and deafened animals. The oCAP amplitude increased with the infrared radiation energy. The preliminary experiment suggests that the near-infrared with lower absorption coefficients can effectively pass through the lymph filled in the cochlea and stimulate the auditory nerve. Further studies will optimize the deafness animal model and determine the optimal stimulation parameters.

  15. Effects of anti-inflammatory vagus nerve stimulation on the cerebral microcirculation in endotoxinemic rats

    PubMed Central

    2012-01-01

    Background In sepsis syndromes the severity of the inflammation triggers microvascular dysfunction and early organ failure. We studied the effects of anti-inflammatory vagus nerve stimulation on the cerebral microcirculatory integrity in an endotoxinemic rat model. Methods In both control and endotoxinemic (5 mg/kg lipopolysaccharide i.v.) rats, the effect of cervical bilateral vagotomy with or without left-sided distal vagus nerve stimulation were compared to non-vagotomized, nonstimulated group (sham). Neurovascular coupling was analyzed by electrical forepaw stimulation, EEG, and cortical laser-Doppler flow recording. Resting cerebral blood flow, evoked potentials and hemodynamic responses, were obtained over a period of 4.5 hours. Regulation of the nitric oxide system (iNOS expression and nitrite/nitrate measurements), cytokines (IFN-γ, TNF-α, IL-6, IL-10), hypoxic and apoptosis signaling molecules (HIF-2α, Bax) were measured at the end of experiments. Results In endotoxinemic rats, vagus nerve stimulation tended to increase anti-inflammatory cytokine levels and resulted in a stabile hemodynamic response (28 ± 13%; versus baseline). Vagotomized animals incurred a pro-inflammatory response (7 ± 4%; P < 0.0001 versus baseline) and produced more HIF-2α than vagotomized vagus nerve stimulated (VNS) animals. Evoked potential amplitudes were stabilized in VNS (15 ± 7 μV; n.s. versus baseline) as compared to vagotomised rats (8 ± 5 μV; P < 0.001 versus baseline). However, no effects were observed on apoptosis markers or nitric oxide levels. Conclusions Vagus nerve stimulation in endotoxinemic rats had a positive effect on neurovascular coupling and stabilized evoked potentials. PMID:22830560

  16. Repetitive nerve stimulation transiently opens the mitochondrial permeability transition pore in motor nerve terminals of symptomatic mutant SOD1 mice.

    PubMed

    Nguyen, Khanh T; Barrett, John N; García-Chacón, Luis; David, Gavriel; Barrett, Ellen F

    2011-06-01

    Mitochondria in motor nerve terminals temporarily sequester large Ca(2+) loads during repetitive stimulation. In wild-type mice this Ca(2+) uptake produces a small (<5 mV), transient depolarization of the mitochondrial membrane potential (Ψ(m), motor nerve stimulated at 100 Hz for 5s). We demonstrate that this stimulation-induced Ψ(m) depolarization attains much higher amplitudes in motor terminals of symptomatic mice expressing the G93A or G85R mutation of human superoxide dismutase 1 (SOD1), models of familial amyotrophic lateral sclerosis (fALS). These large Ψ(m) depolarizations decayed slowly and incremented with successive stimulus trains. Additional Ψ(m) depolarizations occurred that were not synchronized with stimulation. These large Ψ(m) depolarizations were reduced (a) by cyclosporin A (CsA, 1-2 μM), which inhibits opening of the mitochondrial permeability transition pore (mPTP), or (b) by replacing bath Ca(2+) with Sr(2+), which enters motor terminals and mitochondria but does not support mPTP opening. These results are consistent with the hypothesis that the large Ψ(m) depolarizations evoked by repetitive stimulation in motor terminals of symptomatic fALS mice result from mitochondrial dysfunction that increases the likelihood of transient mPTP opening during Ca(2+) influx. Such mPTP openings, a sign of mitochondrial stress, would disrupt motor terminal handling of Ca(2+) loads and might thereby contribute to motor terminal degeneration in fALS mice. Ψ(m) depolarizations resembling those in symptomatic fALS mice could be elicited in wild-type mice following a 0.5-1h exposure to diamide (200 μM), which produces an oxidative stress, but these depolarizations were not reduced by CsA. PMID:21310237

  17. The sweet taste in the calf. II. Glossopharyngeal nerve responses to taste stimulation of the tongue.

    PubMed

    Hård af Segerstad, C H; Hellekant, G

    1989-05-01

    Recordings were obtained from the glossopharyngeal nerve in 1-5-week-old calves during stimulation of the circumvallate tongue area with NaCl, quinine hydrochloride, citric acid, and the sweet compounds: acesulfam-K, aspartame, fructose, galactose, glucose, glycine, lactose, maltose, monellin, Na-saccharin, sucrose, thaumatin, and xylitol. All compounds except aspartame, monellin and thaumatin gave a nerve response. Glycine, followed by Na-saccharin, elicited the largest responses. Sucrose gave the largest response among the disaccharides, while there was no significant difference between the monosaccharides. Expressed as percent of the NaCl responses, the responses to glycine, sucrose, xylitol, fructose, galactose, glucose, lactose and maltose were considerably larger in the glossopharyngeal nerve than in the chorda tympani nerve. This can be taken as an indication that the posterior region of the tongue serves as the major receptive area for sweet in cattle.

  18. Vagus nerve stimulation inhibits cytokine production and attenuates disease severity in rheumatoid arthritis

    PubMed Central

    Koopman, Frieda A.; Chavan, Sangeeta S.; Miljko, Sanda; Grazio, Simeon; Sokolovic, Sekib; Schuurman, P. Richard; Mehta, Ashesh D.; Levine, Yaakov A.; Faltys, Michael; Zitnik, Ralph; Tracey, Kevin J.; Tak, Paul P.

    2016-01-01

    Rheumatoid arthritis (RA) is a heterogeneous, prevalent, chronic autoimmune disease characterized by painful swollen joints and significant disabilities. Symptomatic relief can be achieved in up to 50% of patients using biological agents that inhibit tumor necrosis factor (TNF) or other mechanisms of action, but there are no universally effective therapies. Recent advances in basic and preclinical science reveal that reflex neural circuits inhibit the production of cytokines and inflammation in animal models. One well-characterized cytokine-inhibiting mechanism, termed the “inflammatory reflex,” is dependent upon vagus nerve signals that inhibit cytokine production and attenuate experimental arthritis severity in mice and rats. It previously was unknown whether directly stimulating the inflammatory reflex in humans inhibits TNF production. Here we show that an implantable vagus nerve-stimulating device in epilepsy patients inhibits peripheral blood production of TNF, IL-1β, and IL-6. Vagus nerve stimulation (up to four times daily) in RA patients significantly inhibited TNF production for up to 84 d. Moreover, RA disease severity, as measured by standardized clinical composite scores, improved significantly. Together, these results establish that vagus nerve stimulation targeting the inflammatory reflex modulates TNF production and reduces inflammation in humans. These findings suggest that it is possible to use mechanism-based neuromodulating devices in the experimental therapy of RA and possibly other autoimmune and autoinflammatory diseases. PMID:27382171

  19. 21 CFR 882.5830 - Implanted diaphragmatic/phrenic nerve stimulator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Implanted diaphragmatic/phrenic nerve stimulator. 882.5830 Section 882.5830 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... which an abnormally low amount of air enters the lungs) caused by brain stem disease, high...

  20. 21 CFR 882.5830 - Implanted diaphragmatic/phrenic nerve stimulator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Implanted diaphragmatic/phrenic nerve stimulator. 882.5830 Section 882.5830 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... which an abnormally low amount of air enters the lungs) caused by brain stem disease, high...

  1. 21 CFR 882.5830 - Implanted diaphragmatic/phrenic nerve stimulator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Implanted diaphragmatic/phrenic nerve stimulator. 882.5830 Section 882.5830 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... which an abnormally low amount of air enters the lungs) caused by brain stem disease, high...

  2. Vagus nerve stimulation inhibits cytokine production and attenuates disease severity in rheumatoid arthritis.

    PubMed

    Koopman, Frieda A; Chavan, Sangeeta S; Miljko, Sanda; Grazio, Simeon; Sokolovic, Sekib; Schuurman, P Richard; Mehta, Ashesh D; Levine, Yaakov A; Faltys, Michael; Zitnik, Ralph; Tracey, Kevin J; Tak, Paul P

    2016-07-19

    Rheumatoid arthritis (RA) is a heterogeneous, prevalent, chronic autoimmune disease characterized by painful swollen joints and significant disabilities. Symptomatic relief can be achieved in up to 50% of patients using biological agents that inhibit tumor necrosis factor (TNF) or other mechanisms of action, but there are no universally effective therapies. Recent advances in basic and preclinical science reveal that reflex neural circuits inhibit the production of cytokines and inflammation in animal models. One well-characterized cytokine-inhibiting mechanism, termed the "inflammatory reflex," is dependent upon vagus nerve signals that inhibit cytokine production and attenuate experimental arthritis severity in mice and rats. It previously was unknown whether directly stimulating the inflammatory reflex in humans inhibits TNF production. Here we show that an implantable vagus nerve-stimulating device in epilepsy patients inhibits peripheral blood production of TNF, IL-1β, and IL-6. Vagus nerve stimulation (up to four times daily) in RA patients significantly inhibited TNF production for up to 84 d. Moreover, RA disease severity, as measured by standardized clinical composite scores, improved significantly. Together, these results establish that vagus nerve stimulation targeting the inflammatory reflex modulates TNF production and reduces inflammation in humans. These findings suggest that it is possible to use mechanism-based neuromodulating devices in the experimental therapy of RA and possibly other autoimmune and autoinflammatory diseases. PMID:27382171

  3. Percutaneous tibial nerve stimulation for treatment of overactive bladder and urinary retention in an elderly population.

    PubMed

    Zinkgraf, Kristine; Quinn, Annette O'Leary; Ketterhagen, Debra; Kreuziger, Betty; Stevenson, Katherine

    2009-01-01

    Percutaneous tibial nerve stimulation (PTNS) is a treatment option for patients who present with urinary urgency, frequency, urge incontinence, or urinary retention. When behavior modification and/or pharmacotherapy did not adequately relieve symptoms, this treatment was found to decrease incidence of overactive bladder or retention symptoms in the authors' patient population.

  4. 42 CFR 414.232 - Special payment rules for transcutaneous electrical nerve stimulators (TENS).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Special payment rules for transcutaneous electrical nerve stimulators (TENS). 414.232 Section 414.232 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM PAYMENT FOR PART B MEDICAL AND OTHER HEALTH SERVICES Payment for...

  5. Interlimb Reflexes Induced by Electrical Stimulation of Cutaneous Nerves after Spinal Cord Injury

    PubMed Central

    Butler, Jane E.; Godfrey, Sharlene; Thomas, Christine K.

    2016-01-01

    Whether interlimb reflexes emerge only after a severe insult to the human spinal cord is controversial. Here the aim was to examine interlimb reflexes at rest in participants with chronic (>1 year) spinal cord injury (SCI, n = 17) and able-bodied control participants (n = 5). Cutaneous reflexes were evoked by delivering up to 30 trains of stimuli to either the superficial peroneal nerve on the dorsum of the foot or the radial nerve at the wrist (5 pulses, 300 Hz, approximately every 30 s). Participants were instructed to relax the test muscles prior to the delivery of the stimuli. Electromyographic activity was recorded bilaterally in proximal and distal arm and leg muscles. Superficial peroneal nerve stimulation evoked interlimb reflexes in ipsilateral and contralateral arm and contralateral leg muscles of SCI and control participants. Radial nerve stimulation evoked interlimb reflexes in the ipsilateral leg and contralateral arm muscles of control and SCI participants but only contralateral leg muscles of control participants. Interlimb reflexes evoked by superficial peroneal nerve stimulation were longer in latency and duration, and larger in magnitude in SCI participants. Interlimb reflex properties were similar for both SCI and control groups for radial nerve stimulation. Ascending interlimb reflexes tended to occur with a higher incidence in participants with SCI, while descending interlimb reflexes occurred with a higher incidence in able-bodied participants. However, the overall incidence of interlimb reflexes in SCI and neurologically intact participants was similar which suggests that the neural circuitry underlying these reflexes does not necessarily develop after central nervous system injury. PMID:27049521

  6. Pudendal but not tibial nerve stimulation inhibits bladder contractions induced by stimulation of pontine micturition center in cats.

    PubMed

    Lyon, Timothy D; Ferroni, Matthew C; Kadow, Brian T; Slater, Richard C; Zhang, Zhaocun; Chang, Victor; Lamm, Vladimir; Shen, Bing; Wang, Jicheng; Roppolo, James R; de Groat, William C; Tai, Changfeng

    2016-02-15

    This study examined the possibility that pudendal nerve stimulation (PNS) or tibial nerve stimulation (TNS) inhibits the excitatory pathway from the pontine micturition center (PMC) to the urinary bladder. In decerebrate cats under α-chloralose anesthesia, electrical stimulation of the PMC (40 Hz frequency, 0.2-ms pulse width, 10-25 s duration) using a microelectrode induced bladder contractions >20 cmH2O amplitude when the bladder was filled to 60-70% capacity. PNS or TNS (5 Hz, 0.2 ms) at two and four times the threshold (2T and 4T) to induce anal or toe twitch was applied to inhibit the PMC stimulation-induced bladder contractions. Propranolol, a nonselective β-adrenergic receptor antagonist, was administered intravenously (1 mg/kg i.v.) to determine the role of sympathetic pathways in PNS/TNS inhibition. PNS at both 2T and 4T significantly (P < 0.05) reduced the amplitude and area under the curve of the bladder contractions induced by PMC stimulation, while TNS at 4T facilitated the bladder contractions. Propranolol completely eliminated PNS inhibition and TNS facilitation. This study indicates that PNS, but not TNS, inhibits PMC stimulation-induced bladder contractions via a β-adrenergic mechanism that may occur in the detrusor muscle as a result of reflex activity in lumbar sympathetic nerves. Neither PNS nor TNS activated a central inhibitory pathway with synaptic connections to the sacral parasympathetic neurons that innervate the bladder. Understanding the site of action involved in bladder neuromodulation is important for developing new therapies for bladder disorders. PMID:26676253

  7. Autocrine/paracrine modulation of baroreceptor activity after antidromic stimulation of aortic depressor nerve in vivo.

    PubMed

    Santana-Filho, Valter J; Davis, Greg J; Castania, Jaci A; Ma, Xiuying; Salgado, Helio C; Abboud, Francois M; Fazan, Rubens; Chapleau, Mark W

    2014-02-01

    Activation of the sensory nerve endings of non-myelinated C-fiber afferents evokes release of autocrine/paracrine factors that cause localized vasodilation, neurogenic inflammation, and modulation of sensory nerve activity. The aims of this study were to determine the effect of antidromic electrical stimulation on afferent baroreceptor activity in vivo, and investigate the role of endogenous prostanoids and hydrogen peroxide (H2O2) in mediating changes in nerve activity. Baroreceptor activity was recorded from the left aortic depressor nerve (ADN) in anesthetized rats before and after stimulating the ADN for brief (5–20 s) periods. The rostral end of the ADN was crushed or sectioned beforehand to prevent reflex changes in blood pressure. Antidromic stimulation of ADN using parameters that activate both myelinated A-fibers and non-myelinated C-fibers caused pronounced and long-lasting (> 1 min) inhibition of baroreceptor activity (n = 9, P < 0.05), with the magnitude and duration of inhibition dependent on the duration of the stimulation period (n = 5). Baroreceptor activity was only transiently inhibited after selective stimulation of A-fibers. The inhibition of activity after antidromic stimulation of A and C fibers was prolonged after administration of the cyclooxygenase inhibitor indomethacin (5 mg/kg, IV, n = 7) and abolished after administration of PEG-catalase (104 units/kg, IV, n = 7), an enzyme that catalyzes the decomposition of H2O2 to water and oxygen. The results demonstrate a long-lasting inhibition of baroreceptor activity after antidromic stimulation of ADN and suggest that endogenous prostanoids and H2O2 oppose and mediate the inhibition, respectively. These mechanisms may contribute to rapid baroreceptor resetting during acute hypertension and be engaged during chronic baroreceptor activation therapy in patients with hypertension.

  8. Vagus nerve stimulation: state of the art of stimulation and recording strategies to address autonomic function neuromodulation

    NASA Astrophysics Data System (ADS)

    Guiraud, David; Andreu, David; Bonnet, Stéphane; Carrault, Guy; Couderc, Pascal; Hagège, Albert; Henry, Christine; Hernandez, Alfredo; Karam, Nicole; Le Rolle, Virginie; Mabo, Philippe; Maciejasz, Paweł; Malbert, Charles-Henri; Marijon, Eloi; Maubert, Sandrine; Picq, Chloé; Rossel, Olivier; Bonnet, Jean-Luc

    2016-08-01

    Objective. Neural signals along the vagus nerve (VN) drive many somatic and autonomic functions. The clinical interest of VN stimulation (VNS) is thus potentially huge and has already been demonstrated in epilepsy. However, side effects are often elicited, in addition to the targeted neuromodulation. Approach. This review examines the state of the art of VNS applied to two emerging modulations of autonomic function: heart failure and obesity, especially morbid obesity. Main results. We report that VNS may benefit from improved stimulation delivery using very advanced technologies. However, most of the results from fundamental animal studies still need to be demonstrated in humans.

  9. Transcranial magnetic stimulation assisted by neuronavigation of magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Viesca, N. Angeline; Alcauter, S. Sarael; Barrios, A. Fernando; González, O. Jorge J.; Márquez, F. Jorge A.

    2012-10-01

    Technological advance has improved the way scientists and doctors can learn about the brain and treat different disorders. A non-invasive method used for this is Transcranial Magnetic Stimulation (TMS) based on neuron excitation by electromagnetic induction. Combining this method with functional Magnetic Resonance Images (fMRI), it is intended to improve the localization technique of cortical brain structures by designing an extracranial localization system, based on Alcauter et al. work.

  10. Practical magnetic resonance imaging evaluation of peripheral nerves in children: magnetic resonance neurography.

    PubMed

    Cortes, Cesar; Ramos, Yanerys; Restrepo, Ricardo; Restrepo, Jose Andres; Grossman, John A I; Lee, Edward Y

    2013-07-01

    Magnetic resonance (MR) imaging is an excellent tool for the evaluation of peripheral nerves in children not only because of its excellent soft tissue contrast resolution but also because it is noninvasive and does not use ionizing radiation. In nonconclusive cases, MR neurography can be complementary to physical examination and electromyography in identifying a specific affected nerve and the site of the lesion. This article reviews the MR imaging technique used in the evaluation of peripheral nerves (ie, MR neurography), its major indications, and the common pathologic conditions encountered in the pediatric population.

  11. Magnetically stimulated diffusion of Rydberg gases.

    PubMed

    Dumin, Yurii V

    2013-01-18

    The specific kind of diffusion stimulated (rather than suppressed) by the external magnetic field, which was predicted for the first time by Schmelcher and Cederbaum in 1992, is considered here for the case of high-angular-momentum (i.e., approximately "circular") Rydberg atoms. The coefficient of such diffusion was calculated by a purely analytical approach and was found to be very relevant to the experiments on antihydrogen formation.

  12. Simulation of Nerve Bundle Activation by Simultaneous Multipoint Extracellular Stimulation with Surface Electrodes

    NASA Astrophysics Data System (ADS)

    Takahashi, Hirokazu; Nakao, Masayuki; Kaga, Kimitaka

    Neural prostheses for restoring lost functions can benefit from selective activation of nerves. We had previously proposed a multiple gating stimulation, which can selectively activate a desired portion of nerve bundle, irrespective of a density of the electrode. In this paper, we discuss the design of electrode array and effective strategies to determine the stimulus parameters. A large electrode was less affected by the relative location of electrodes and the node of Ranvier, suggesting that a rectangular electrode, whose long side along a nerve bundle is longer than the internodal distance, i.e., on the order of 1 mm, would be more effective rather than a disk electrode. We could estimate an appropriate current at each electrode was a blocking threshold. For the lateral gating stimulation, the gate current should be set above the threshold, while, for depth-wise gating stimulation, the gate current should be set below the threshold. The spatial resolution of lateral gating stimulation is theoretically estimated at least at 50 μm when the grid of array was 1.2 mm, and that of depth-wise gating stimulation at 50 μm.

  13. Aligned Nanofibers from Polypyrrole/Graphene as Electrodes for Regeneration of Optic Nerve via Electrical Stimulation.

    PubMed

    Yan, Lu; Zhao, Bingxin; Liu, Xiaohong; Li, Xuan; Zeng, Chao; Shi, Haiyan; Xu, Xiaoxue; Lin, Tong; Dai, Liming; Liu, Yong

    2016-03-23

    The damage of optic nerve will cause permanent visual field loss and irreversible ocular diseases, such as glaucoma. The damage of optic nerve is mainly derived from the atrophy, apoptosis or death of retinal ganglion cells (RGCs). Though some progress has been achieved on electronic retinal implants that can electrically stimulate undamaged parts of RGCs or retina to transfer signals, stimulated self-repair/regeneration of RGCs has not been realized yet. The key challenge for development of electrically stimulated regeneration of RGCs is the selection of stimulation electrodes with a sufficient safe charge injection limit (Q(inj), i.e., electrochemical capacitance). Most traditional electrodes tend to have low Q(inj) values. Herein, we synthesized polypyrrole functionalized graphene (PPy-G) via a facile but efficient polymerization-enhanced ball milling method for the first time. This technique could not only efficiently introduce electron-acceptor nitrogen to enhance capacitance, but also remain a conductive platform-the π-π conjugated carbon plane for charge transportation. PPy-G based aligned nanofibers were subsequently fabricated for guided growth and electrical stimulation (ES) of RGCs. Significantly enhanced viability, neurite outgrowth and antiaging ability of RGCs were observed after ES, suggesting possibilities for regeneration of optic nerve via ES on the suitable nanoelectrodes. PMID:26926578

  14. A review of sacral nerve stimulation parameters used in the treatment of faecal incontinence.

    PubMed

    Devane, Liam A; Evers, Judith; Jones, James F X; Ronan O'Connell, P

    2015-06-01

    Sacral nerve stimulation (SNS) was originally developed in the field of urinary incontinence. Without adaptation, it was subsequently applied to treat faecal incontinence. SNS has now become a first line therapy for this socially disabling condition, however the mechanism of action is unknown. This review examines the evidence for stimulation parameters currently used for SNS in humans and considers the potential electrophysiological effects of changing these parameters. However, without a proper understanding of the physiology of SNS, changing stimulation parameters remains empirical. PMID:25623489

  15. Serratus muscle stimulation effectively treats notalgia paresthetica caused by long thoracic nerve dysfunction: a case series.

    PubMed

    Wang, Charlie K; Gowda, Alpana; Barad, Meredith; Mackey, Sean C; Carroll, Ian R

    2009-01-01

    Currently, notalgia paresthetica (NP) is a poorly-understood condition diagnosed on the basis of pruritus, pain, or both, in the area medial to the scapula and lateral to the thoracic spine. It has been proposed that NP is caused by degenerative changes to the T2-T6 vertebrae, genetic disposition, or nerve entrapment of the posterior rami of spinal nerves arising at T2-T6. Despite considerable research, the etiology of NP remains unclear, and a multitude of different treatment modalities have correspondingly met with varying degrees of success. Here we demonstrate that NP can be caused by long thoracic nerve injury leading to serratus anterior dysfunction, and that electrical muscle stimulation (EMS) of the serratus anterior can successfully and conservatively treat NP. In four cases of NP with known injury to the long thoracic nerve we performed transcutaneous EMS to the serratus anterior in an area far lateral to the site of pain and pruritus, resulting in significant and rapid pain relief. These findings are the first to identify long thoracic nerve injury as a cause for notalgia paresthetica and electrical muscle stimulation of the serratus anterior as a possible treatment, and we discuss the implications of these findings on better diagnosing and treating notalgia paresthetica. PMID:19772656

  16. Serratus muscle stimulation effectively treats notalgia paresthetica caused by long thoracic nerve dysfunction: a case series

    PubMed Central

    2009-01-01

    Currently, notalgia paresthetica (NP) is a poorly-understood condition diagnosed on the basis of pruritus, pain, or both, in the area medial to the scapula and lateral to the thoracic spine. It has been proposed that NP is caused by degenerative changes to the T2-T6 vertebrae, genetic disposition, or nerve entrapment of the posterior rami of spinal nerves arising at T2-T6. Despite considerable research, the etiology of NP remains unclear, and a multitude of different treatment modalities have correspondingly met with varying degrees of success. Here we demonstrate that NP can be caused by long thoracic nerve injury leading to serratus anterior dysfunction, and that electrical muscle stimulation (EMS) of the serratus anterior can successfully and conservatively treat NP. In four cases of NP with known injury to the long thoracic nerve we performed transcutaneous EMS to the serratus anterior in an area far lateral to the site of pain and pruritus, resulting in significant and rapid pain relief. These findings are the first to identify long thoracic nerve injury as a cause for notalgia paresthetica and electrical muscle stimulation of the serratus anterior as a possible treatment, and we discuss the implications of these findings on better diagnosing and treating notalgia paresthetica. PMID:19772656

  17. Sympathetic nerve stimulation induces local endothelial Ca2+ signals to oppose vasoconstriction of mouse mesenteric arteries

    PubMed Central

    Nausch, Lydia W. M.; Bonev, Adrian D.; Heppner, Thomas J.; Tallini, Yvonne; Kotlikoff, Michael I.

    2012-01-01

    It is generally accepted that the endothelium regulates vascular tone independent of the activity of the sympathetic nervous system. Here, we tested the hypothesis that the activation of sympathetic nerves engages the endothelium to oppose vasoconstriction. Local inositol 1,4,5-trisphosphate (IP3)-mediated Ca2+ signals (“pulsars”) in or near endothelial projections to vascular smooth muscle (VSM) were measured in an en face mouse mesenteric artery preparation. Electrical field stimulation of sympathetic nerves induced an increase in endothelial cell (EC) Ca2+ pulsars, recruiting new pulsar sites without affecting activity at existing sites. This increase in Ca2+ pulsars was blocked by bath application of the α-adrenergic receptor antagonist prazosin or by TTX but was unaffected by directly picospritzing the α-adrenergic receptor agonist phenylephrine onto the vascular endothelium, indicating that nerve-derived norepinephrine acted through α-adrenergic receptors on smooth muscle cells. Moreover, EC Ca2+ signaling was not blocked by inhibitors of purinergic receptors, ryanodine receptors, or voltage-dependent Ca2+ channels, suggesting a role for IP3, rather than Ca2+, in VSM-to-endothelium communication. Block of intermediate-conductance Ca2+-sensitive K+ channels, which have been shown to colocalize with IP3 receptors in endothelial projections to VSM, enhanced nerve-evoked constriction. Collectively, our results support the concept of a transcellular negative feedback module whereby sympathetic nerve stimulation elevates EC Ca2+ signals to oppose vasoconstriction. PMID:22140050

  18. Magnetic stimulation for non-homogeneous biological structures

    PubMed Central

    Krasteva, Vessela T; Papazov, Sava P; Daskalov, Ivan K

    2002-01-01

    Background Magnetic stimulation has gained relatively wide application in studying nervous system structures. This technology has the advantage of reduced excitation of sensory nerve endings, and hence results in quasi-painless action. It has become clinically accepted modality for brain stimulation. However, theoretical and practical solutions for assessment of induced current distribution need more detailed and accurate consideration. Some possible analyses are proposed for distribution of the current induced from excitation current contours of different shape and disposition. Relatively non-difficult solutions are shown, applicable for two- and three-dimensional analysis. Methods The boundary conditions for field analysis by the internal Dirichlet problem are introduced, based on the vector potential field excited by external current coils. The feedback from the induced eddy currents is neglected. Finite element modeling is applied for obtaining the electromagnetic fields distribution in a non-homogeneous domain. Results The distributions were obtained in a non-homogeneous structure comprised of homogeneous layers. A tendency was found of the induced currents to follow paths in lower resistivity layers, deviating from the expected theoretical course for a homogeneous domain. Current density concentrations occur at the boundary between layers, suggesting the possibility for focusing on, or predicting of, a zone of stimulation. Conclusion The theoretical basis and simplified approach for generation of 3D FEM networks for magnetic stimulation analysis are presented, applicable in non-homogeneous and non-linear media. The inconveniences of introducing external excitation currents are avoided. Thus, the possibilities are improved for analysis of distributions induced by time-varying currents from contours of various geometry and position with respect to the medium. PMID:12437784

  19. Hypoglossal Nerve Stimulator Implantation in an Adolescent With Down Syndrome and Sleep Apnea.

    PubMed

    Diercks, Gillian R; Keamy, Donald; Kinane, Thomas Bernard; Skotko, Brian; Schwartz, Allison; Grealish, Ellen; Dobrowski, John; Soose, Ryan; Hartnick, Christopher J

    2016-05-01

    Obstructive sleep apnea (OSA) is more common in children with Down syndrome, affecting up to 60% of patients, and may persist in up to 50% of patients after adenotonsillectomy. These children with persistent moderate to severe OSA require continuous positive airway pressure, which is often poorly tolerated, or even tracheotomy for severe cases. The hypoglossal nerve stimulator is an implantable device that produces an electrical impulse to the anterior branches of the hypoglossal nerve, resulting in tongue protrusion in response to respiratory variation. It is an effective treatment of sleep apnea in select adult patients because it allows for alleviation of tongue base collapse, improving airway obstruction. Herein we describe the first pediatric hypoglossal nerve stimulator implantation, which was performed in an adolescent with Down syndrome and refractory severe OSA (apnea hypopnea index [AHI]: 48.5 events/hour). The patient would not tolerate continuous positive airway pressure and required a long-standing tracheotomy. Hypoglossal nerve stimulator therapy was well tolerated and effective, resulting in significant improvement in the patient's OSA (overall AHI: 3.4 events/hour; AHI: 2.5-9.7 events/hour at optimal voltage settings depending on sleep stage and body position). Five months after implantation, the patient's tracheotomy was successfully removed and he continues to do well with nightly therapy. PMID:27244805

  20. Transcutaneous Electrical Nerve Stimulation (TENS) A Possible Aid for Pain Relief in Developing Countries?

    PubMed Central

    Tashani, O; Johnson, MI

    2009-01-01

    Transcutaneous electrical nerve stimulation (TENS) refers to the delivery of electrical currents through the skin to activate peripheral nerves. The technique is widely used in developed countries to relieve a wide range of acute and chronic pain conditions, including pain resulting from cancer and its treatment. There are many systematic reviews on TENS although evidence is often inconclusive because of shortcomings in randomised control trials methodology. In this overview the basic science behind TENS will be discussed, the evidence of its effectiveness in specific clinical conditions analysed and a case for its use in pain management in developing countries will be made. PMID:21483510

  1. Transcutaneous Electrical Nerve Stimulation (TENS) A Possible Aid for Pain Relief in Developing Countries?

    PubMed

    Tashani, O; Johnson, Mi

    2009-06-01

    Transcutaneous electrical nerve stimulation (TENS) refers to the delivery of electrical currents through the skin to activate peripheral nerves. The technique is widely used in developed countries to relieve a wide range of acute and chronic pain conditions, including pain resulting from cancer and its treatment. There are many systematic reviews on TENS although evidence is often inconclusive because of shortcomings in randomised control trials methodology. In this overview the basic science behind TENS will be discussed, the evidence of its effectiveness in specific clinical conditions analysed and a case for its use in pain management in developing countries will be made.

  2. Dosimetry of typical transcranial magnetic stimulation devices

    NASA Astrophysics Data System (ADS)

    Lu, Mai; Ueno, Shoogo

    2010-05-01

    The therapeutic staff using transcranial magnetic stimulation (TMS) devices could be exposed to magnetic pulses. In this paper, dependence of induced currents in real human man model on different coil shapes, distance between the coil and man model as well as the rotation of the coil in space have been investigated by employing impedance method. It was found that the figure-of-eight coil has less leakage magnetic field and low current density induced in the body compared with the round coil. The TMS power supply cables play an important role in the induced current density in human body. The induced current density in TMS operator decreased as the coil rotates from parallel position to perpendicular position. Our present study shows that TMS operator should stand at least 110 cm apart from the coil.

  3. Waveform efficiency analysis of auditory nerve fiber stimulation for cochlear implants.

    PubMed

    Lotfi Navaii, Mehdi; Sadjedi, Hamed; Jalali, Mohsen

    2013-09-01

    Evaluation of the electrical stimulation efficiency of various stimulating waveforms is an important issue for efficient neural stimulator design. Concerning the implantable micro devices design, it is also necessary to consider the feasibility of hardware implementation of the desired waveforms. In this paper, the charge, power and energy efficiency of four waveforms (i.e. square, rising ramp, triangular and rising ramp-decaying exponential) in various durations have been simulated and evaluated based on the computational model of the auditory nerve fibers. Moreover, for a fair comparison of their feasibility, a fully integrated current generator circuit has been developed so that the desired stimulating waveforms can be generated. The simulation results show that stimulation with the square waveforms is a proper choice in short and intermediate durations while the rising ramp-decaying exponential or triangular waveforms can be employed for long durations. PMID:23918258

  4. A point process framework for modeling electrical stimulation of the auditory nerve

    PubMed Central

    Rubinstein, Jay T.; Shea-Brown, Eric

    2012-01-01

    Model-based studies of responses of auditory nerve fibers to electrical stimulation can provide insight into the functioning of cochlear implants. Ideally, these studies can identify limitations in sound processing strategies and lead to improved methods for providing sound information to cochlear implant users. To accomplish this, models must accurately describe spiking activity while avoiding excessive complexity that would preclude large-scale simulations of populations of auditory nerve fibers and obscure insight into the mechanisms that influence neural encoding of sound information. In this spirit, we develop a point process model of individual auditory nerve fibers that provides a compact and accurate description of neural responses to electric stimulation. Inspired by the framework of generalized linear models, the proposed model consists of a cascade of linear and nonlinear stages. We show how each of these stages can be associated with biophysical mechanisms and related to models of neuronal dynamics. Moreover, we derive a semianalytical procedure that uniquely determines each parameter in the model on the basis of fundamental statistics from recordings of single fiber responses to electric stimulation, including threshold, relative spread, jitter, and chronaxie. The model also accounts for refractory and summation effects that influence the responses of auditory nerve fibers to high pulse rate stimulation. Throughout, we compare model predictions to published physiological data of response to high and low pulse rate stimulation. We find that the model, although constructed to fit data from single and paired pulse experiments, can accurately predict responses to unmodulated and modulated pulse train stimuli. We close by performing an ideal observer analysis of simulated spike trains in response to sinusoidally amplitude modulated stimuli and find that carrier pulse rate does not affect modulation detection thresholds. PMID:22673331

  5. Long-lasting modulation of human motor cortex following prolonged transcutaneous electrical nerve stimulation (TENS) of forearm muscles: evidence of reciprocal inhibition and facilitation.

    PubMed

    Tinazzi, Michele; Zarattini, Stefano; Valeriani, Massimiliano; Romito, Silvia; Farina, Simona; Moretto, Giuseppe; Smania, Nicola; Fiaschi, Antonio; Abbruzzese, Giovanni

    2005-03-01

    Several lines of evidence indicate that motor cortex excitability can be modulated by manipulation of afferent inputs, like peripheral electrical stimulation. Most studies in humans mainly dealt with the effects of prolonged low-frequency peripheral nerve stimulation on motor cortical excitability, despite its being known from animal studies that high-frequency stimulation can also result in changes of the cortical excitability. To investigate the possible effects of high-frequency peripheral stimulation on motor cortical excitability we recorded motor-evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) of the left motor cortex from the right flexor carpi radialis (FCR), extensor carpi radialis (ECR), and first dorsal interosseous (FDI) in normal subjects, before and after transcutaneous electrical nerve stimulation (TENS) of 30 min duration applied over the FCR. The amplitude of MEPs from the FRC was significantly reduced from 10 to 35 min after TENS while the amplitude of MEPs from ECR was increased. No effects were observed in the FDI muscle. Indices of peripheral nerve (M-wave) and spinal cord excitability (H waves) did not change throughout the experiment. Electrical stimulation of the lateral antebrachial cutaneous nerve has no significant effect on motor cortex excitability. These findings suggest that TENS of forearm muscles can induce transient reciprocal inhibitory and facilitatory changes in corticomotoneuronal excitability of forearm flexor and extensor muscles lasting several minutes. These changes probably may occur at cortical site and seem to be mainly dependent on stimulation of muscle afferents. These findings might eventually lead to practical applications in rehabilitation, especially in those syndromes in which the excitatory and inhibitory balance between agonist and antagonist is severely impaired, such as spasticity and dystonia.

  6. High and low frequency transcutaneous electrical nerve stimulation inhibits nociceptive responses induced by CO2 laser stimulation in humans.

    PubMed

    de Tommaso, Marina; Fiore, Pietro; Camporeale, Alfonso; Guido, Marco; Libro, Giuseppe; Losito, Luciana; Megna, Marisa; Puca, Francomichele; Megna, Gianfranco

    2003-05-15

    The aim of the study was to evaluate the effects of transcutaneous electric nerve stimulation (TENS) on CO(2) laser evoked potentials (LEPs) in 16 normal subjects. The volar side of the forearm was stimulated by 10 Hz TENS in eight subjects and by 100 Hz TENS in the remainder; the skin of the forearm was stimulated by CO(2) laser and the LEPs were recorded in basal conditions and soon after and 15 min after TENS. Both low and high frequency TENS significantly reduced the subjective rating of heat stimuli and the LEPs amplitude, although high frequency TENS appeared more efficacious. TENS seemed to exert a mild inhibition of the perception and processing of pain induced by laser Adelta fibres activation; the implications of these effects in the clinical employment of TENS remain to be clarified. PMID:12727307

  7. High and low frequency transcutaneous electrical nerve stimulation inhibits nociceptive responses induced by CO2 laser stimulation in humans.

    PubMed

    de Tommaso, Marina; Fiore, Pietro; Camporeale, Alfonso; Guido, Marco; Libro, Giuseppe; Losito, Luciana; Megna, Marisa; Puca, Francomichele; Megna, Gianfranco

    2003-05-15

    The aim of the study was to evaluate the effects of transcutaneous electric nerve stimulation (TENS) on CO(2) laser evoked potentials (LEPs) in 16 normal subjects. The volar side of the forearm was stimulated by 10 Hz TENS in eight subjects and by 100 Hz TENS in the remainder; the skin of the forearm was stimulated by CO(2) laser and the LEPs were recorded in basal conditions and soon after and 15 min after TENS. Both low and high frequency TENS significantly reduced the subjective rating of heat stimuli and the LEPs amplitude, although high frequency TENS appeared more efficacious. TENS seemed to exert a mild inhibition of the perception and processing of pain induced by laser Adelta fibres activation; the implications of these effects in the clinical employment of TENS remain to be clarified.

  8. Giant Lipomatosis of the Sciatic Nerve: Unique Magnetic Resonance Imaging Findings.

    PubMed

    Sarp, Ali Firat; Pekcevik, Yeliz

    2016-04-01

    Lipomatosis of the nerve, also known as fibrolipomatous hamartoma, is characterized by the infiltration of the nerve by fibro-fatty tissue. The affected nerve becomes thicker, and it simulates a mass lesion. Lipomatosis usually affects the median nerve and lipomatosis of the sciatic nerve is extremely rare. Magnetic resonance imaging (MRI) is the key to diagnosis, and it is usually pathognomonic. In this report, MRI and diffusion-weighted MRI findings of a case of a giant sciatic nerve lipomatosis without macrodactyly are presented. The MRI findings are unique, and awareness of the MRI features of this rare soft tissue mass may prevent unnecessary biopsies and surgeries. PMID:27679695

  9. [High resolution (3 T) magnetic resonance neurography of the sciatic nerve].

    PubMed

    Cejas, C; Aguilar, M; Falcón, L; Caneo, N; Acuña, M C

    2013-01-01

    Magnetic resonance (MR) neurography refers to a set of techniques that enable the structure of the peripheral nerves and nerve plexuses to be evaluated optimally. New two-dimensional and three-dimensional neurographic sequences, in particular in 3T scanners, achieve excellent contrast between the nerve and perineural structures. MR neurography makes it possible to distinguish between the normal fascicular pattern of the nerve and anomalies like inflammation, trauma, and tumor that can affect nerves. In this article, we describe the structure of the sciatic nerve, its characteristics on MR neurography, and the most common diseases that affect it.

  10. Giant Lipomatosis of the Sciatic Nerve: Unique Magnetic Resonance Imaging Findings

    PubMed Central

    Sarp, Ali Firat; Pekcevik, Yeliz

    2016-01-01

    Lipomatosis of the nerve, also known as fibrolipomatous hamartoma, is characterized by the infiltration of the nerve by fibro-fatty tissue. The affected nerve becomes thicker, and it simulates a mass lesion. Lipomatosis usually affects the median nerve and lipomatosis of the sciatic nerve is extremely rare. Magnetic resonance imaging (MRI) is the key to diagnosis, and it is usually pathognomonic. In this report, MRI and diffusion-weighted MRI findings of a case of a giant sciatic nerve lipomatosis without macrodactyly are presented. The MRI findings are unique, and awareness of the MRI features of this rare soft tissue mass may prevent unnecessary biopsies and surgeries.

  11. Giant Lipomatosis of the Sciatic Nerve: Unique Magnetic Resonance Imaging Findings

    PubMed Central

    Sarp, Ali Firat; Pekcevik, Yeliz

    2016-01-01

    Lipomatosis of the nerve, also known as fibrolipomatous hamartoma, is characterized by the infiltration of the nerve by fibro-fatty tissue. The affected nerve becomes thicker, and it simulates a mass lesion. Lipomatosis usually affects the median nerve and lipomatosis of the sciatic nerve is extremely rare. Magnetic resonance imaging (MRI) is the key to diagnosis, and it is usually pathognomonic. In this report, MRI and diffusion-weighted MRI findings of a case of a giant sciatic nerve lipomatosis without macrodactyly are presented. The MRI findings are unique, and awareness of the MRI features of this rare soft tissue mass may prevent unnecessary biopsies and surgeries. PMID:27679695

  12. Comparative analysis of transverse intrafascicular multichannel, longitudinal intrafascicular and multipolar cuff electrodes for the selective stimulation of nerve fascicles

    NASA Astrophysics Data System (ADS)

    Badia, Jordi; Boretius, Tim; Andreu, David; Azevedo-Coste, Christine; Stieglitz, Thomas; Navarro, Xavier

    2011-06-01

    The selection of a suitable nerve electrode for neuroprosthetic applications implies a trade-off between invasiveness and selectivity, wherein the ultimate goal is achieving the highest selectivity for a high number of nerve fascicles by the least invasiveness and potential damage to the nerve. The transverse intrafascicular multichannel electrode (TIME) is intended to be transversally inserted into the peripheral nerve and to be useful to selectively activate subsets of axons in different fascicles within the same nerve. We present a comparative study of TIME, LIFE and multipolar cuff electrodes for the selective stimulation of small nerves. The electrodes were implanted on the rat sciatic nerve, and the activation of gastrocnemius, plantar and tibialis anterior muscles was recorded by EMG signals. Thus, the study allowed us to ascertain the selectivity of stimulation at the interfascicular and also at the intrafascicular level. The results of this study indicate that (1) intrafascicular electrodes (LIFE and TIME) provide excitation circumscribed to the implanted fascicle, whereas extraneural electrodes (cuffs) predominantly excite nerve fascicles located superficially; (2) the minimum threshold for muscle activation with TIME and LIFE was significantly lower than with cuff electrodes; (3) TIME allowed us to selectively activate the three tested muscles when stimulating through different active sites of one device, both at inter- and intrafascicular levels, whereas selective activation using multipolar cuff (with a longitudinal tripolar stimulation configuration) was only possible for two muscles, at the interfascicular level, and LIFE did not activate selectively more than one muscle in the implanted nerve fascicle.

  13. Comparison of skin sensory thresholds using pre-programmed or single-frequency transcutaneous electrical nerve stimulation

    PubMed Central

    Kang, Jong Ho

    2015-01-01

    [Purpose] The purpose of the present study was to compare the sensory thresholds of healthy subjects using pre-programmed or single-frequency transcutaneous electrical nerve stimulation. [Subjects] Ninety healthy adult subjects were randomly assigned to pre-programmed or single-frequency stimulation groups, each consisting of 45 participants. [Methods] Sensory thresholds were measured in the participants’ forearms using von Frey filaments before and after pre-programmed or single-frequency transcutaneous electrical nerve stimulation, and the result in values were analyzed. [Results] Significant increases in sensory threshold after stimulation were observed in both groups. However, there were no significant differences between the two groups in sensory thresholds after stimulation or in the magnitude of threshold increases following stimulation. [Conclusion] Our results show that there are no differences between sensory threshold increases induced by pre-programmed and single-frequency transcutaneous electrical nerve stimulation. PMID:26834358

  14. Novel transcranial magnetic stimulation coil for mice

    NASA Astrophysics Data System (ADS)

    March, Stephen; Stark, Spencer; Crowther, Lawrence; Hadimani, Ravi; Jiles, David

    2014-03-01

    Transcranial magnetic stimulation (TMS) shows potential for non-invasive treatment of various neurological disorders. Significant work has been performed on the design of coils used for TMS on human subjects but few reports have been made on the design of coils for use on the brains of animals such as mice. This work is needed as TMS studies utilizing mice can allow rapid preclinical development of TMS for human disorders but the coil designs developed for use on humans are inadequate for optimal stimulation of the much smaller mouse brain. A novel TMS coil has been developed with the goal of inducing strong and focused electric fields for the stimulation of small animals such as mice. Calculations of induced electric fields were performed utilizing an MRI derived inhomogeneous model of an adult male mouse. Mechanical and thermal analysis of this new TMS helmet-coil design have also been performed at anticipated TMS operating conditions to ensure mechanical stability of the new coil and establish expected linear attraction and rotational force values. Calculated temperature increases for typical stimulation periods indicate the helmet-coil system is capable of operating within established medical standards. A prototype of the coil has been fabricated and characterization results are presented.

  15. Diffusion tensor magnetic resonance imaging of regeneration/degeneration after rat sciatic nerve injury

    NASA Astrophysics Data System (ADS)

    Sig Hwang, Min; Perrin, George; Muir, David; Mareci, Thomas

    2005-11-01

    Diffusion tensor imaging was performed to investigate myelination and demyelination spatiotemporally in cut or crushed excised rat sciatic nerves in a 17.6 T magnet with a solenoid RF coil. Orientation independent measures of water diffusion, fractional anisotropy (FA) and averaged diffusivity (), were examined as MR parameters for the quantification of the myelin within the major peripheral nerve. Crushed nerves initially demonstrated decreased FA, followed by increase to FA of normal nerve with time. At 14 days post injury, FA of the nerve is high, 0.85, at the site proximal to the injury then FA decreases in a proximodistal gradient because the nerve remains more demyelinated toward the distal area. Cut sciatic nerves displayed a prolonged decrease of FA with time after injury. Also FA correlates with in these nerves. Therefore FA or may be a good indicator of myelination and demyelination in rat sciatic nerves and FA appears to be a more sensitive indicator of myelin.

  16. Recovery characteristics of the electrically stimulated auditory nerve in deafened guinea pigs: relation to neuronal status.

    PubMed

    Ramekers, Dyan; Versnel, Huib; Strahl, Stefan B; Klis, Sjaak F L; Grolman, Wilko

    2015-03-01

    Successful cochlear implant performance requires adequate responsiveness of the auditory nerve to prolonged pulsatile electrical stimulation. Degeneration of the auditory nerve as a result of severe hair cell loss could considerably compromise this ability. The main objective of this study was to characterize the recovery of the electrically stimulated auditory nerve, as well as to evaluate possible changes caused by deafness-induced degeneration. To this end we studied temporal responsiveness of the auditory nerve in a guinea pig model of sensorineural hearing loss. Using masker-probe and pulse train paradigms we compared electrically evoked compound action potentials (eCAPs) in normal-hearing animals with those in animals with moderate (two weeks after ototoxic treatment) and severe (six weeks after ototoxic treatment) loss of spiral ganglion cells (SGCs). Masker-probe interval and pulse train inter-pulse interval was varied from 0.3 to 16 ms. Whereas recovery assessed with masker-probe was roughly similar for normal-hearing and both groups of deafened animals, it was considerably faster for six weeks deaf animals (τ ≈ 1.2 ms) than for two weeks deaf or normal-hearing animals (τ ≈ 3-4 ms) when 100-ms pulse trains were applied. Latency increased with decreasing inter-pulse intervals, and this was more pronounced with pulse trains than with masker-probe stimulation. With high frequency pulse train stimulation eCAP amplitudes were modulated for deafened animals, meaning that amplitudes for odd pulse numbers were larger than for even pulses. The relative refractory period (τ) and the modulation depth of the eCAP amplitude for pulse trains, as well as the latency increase for both paradigms significantly correlated with quantified measures of auditory nerve degeneration (size and packing density of SGCs). In addition to these findings, separate masker-probe recovery functions for the eCAP N1 and N2 peaks displayed a robust non-monotonic or shoulder

  17. Recovery characteristics of the electrically stimulated auditory nerve in deafened guinea pigs: relation to neuronal status.

    PubMed

    Ramekers, Dyan; Versnel, Huib; Strahl, Stefan B; Klis, Sjaak F L; Grolman, Wilko

    2015-03-01

    Successful cochlear implant performance requires adequate responsiveness of the auditory nerve to prolonged pulsatile electrical stimulation. Degeneration of the auditory nerve as a result of severe hair cell loss could considerably compromise this ability. The main objective of this study was to characterize the recovery of the electrically stimulated auditory nerve, as well as to evaluate possible changes caused by deafness-induced degeneration. To this end we studied temporal responsiveness of the auditory nerve in a guinea pig model of sensorineural hearing loss. Using masker-probe and pulse train paradigms we compared electrically evoked compound action potentials (eCAPs) in normal-hearing animals with those in animals with moderate (two weeks after ototoxic treatment) and severe (six weeks after ototoxic treatment) loss of spiral ganglion cells (SGCs). Masker-probe interval and pulse train inter-pulse interval was varied from 0.3 to 16 ms. Whereas recovery assessed with masker-probe was roughly similar for normal-hearing and both groups of deafened animals, it was considerably faster for six weeks deaf animals (τ ≈ 1.2 ms) than for two weeks deaf or normal-hearing animals (τ ≈ 3-4 ms) when 100-ms pulse trains were applied. Latency increased with decreasing inter-pulse intervals, and this was more pronounced with pulse trains than with masker-probe stimulation. With high frequency pulse train stimulation eCAP amplitudes were modulated for deafened animals, meaning that amplitudes for odd pulse numbers were larger than for even pulses. The relative refractory period (τ) and the modulation depth of the eCAP amplitude for pulse trains, as well as the latency increase for both paradigms significantly correlated with quantified measures of auditory nerve degeneration (size and packing density of SGCs). In addition to these findings, separate masker-probe recovery functions for the eCAP N1 and N2 peaks displayed a robust non-monotonic or shoulder

  18. Naloxone reversible reduction in brain monoamine synthesis following sciatic nerve stimulation.

    PubMed

    Nissbrandt, H; Yao, T; Thorén, P; Svensson, T H

    1982-01-01

    Brain monoaminergic neurons seem to be influenced by endogenous opioid systems as judged from largely indirect evidence. In an attempt to more directly study this interaction, we have analyzed the effect of sciatic nerve stimulation (rectangular pulses, frequency 3 Hz, pulse duration 0.2 msec, current intensity 6-20 times muscle twitch threshold) on the in vivo rate of tyrosine-and tryptophanhydroxylation, respectively, in the rat brain. This stimulation procedure has previously been shown to evoke naloxone reversible pain threshold elevation and a longlasting blood pressure reduction rats, with maximum reached about 1.5 h after stimulation. The formation of DOPA and 5-HTP in various parts of the central nervous system during 30 min after inhibition of L-amino-acid-decarboxylase by NSD 1015 was measured. Two hours after the sciatic nerve stimulation procedure a significant decrease in DOPA formation was obtained in the cerebral cortex and in the spinal cord. This effect was reversed by pretreatment with a high dose of naloxone (15 mg/kg s.c., 10 min before stimulation). A reduction in 5-HTP formation was also obtained in the cerebral cortex, with a concomitant reduction in tryptophan concentration. These effects appeared to be antagonized by naloxone treatment. In the spinal cord there was no change in the 5-HTP accumulation after stimulation, but an increase after stimulation plus naloxone pretreatment was obtained. These data infer that the activity of some central monoamine systems, such as the NA pathways originating in locus coeruleus can be reduced by physiological activation of endogenous opioid systems. This effect of the acupuncture like stimulation procedure may be related to clinically reported actions of acupuncture stimulation, which apart from pain relief include, for example, antagonism of heroin abstinence symptoms.

  19. Hypoglossal nerve stimulation rescue surgery after multiple multilevel procedures for obstructive sleep apnea.

    PubMed

    Strohl, Madeleine; Strohl, Kingman; Palomo, J Martin; Ponsky, Diana

    2016-01-01

    Hypoglossal nerve stimulation (HNS) is a new procedure offered for the treatment of moderate-to-severe obstructive sleep apnea (OSA) that has been shown to decrease the severity and symptoms of OSA in select patients. We report on a case of a patient with persistent symptoms and findings of OSA despite a history of multiple multilevel procedures, including an uvulopalatopharyngoplasty (UPPP) with revision, a genioglossus advancement, and a maxillomandibular advancement. The patient then underwent HNS with significant improvement of his symptoms and severity. The success of this patient's HNS surgery demonstrates that we need to examine where HNS fits into the approach to surgery for OSA. There could be benefit to considering cranial nerve stimulation earlier than conventional approaches for select patients. PMID:26700261

  20. Analytical theory for extracellular electrical stimulation of nerve with focal electrodes. II. Passive myelinated axon.

    PubMed Central

    Rubinstein, J T

    1991-01-01

    The cable model of a passive, myelinated fiber is derived using the theory of electromagnetic propagation in periodic structures. The cable may be excited by an intracellular source or by an arbitrary, time-varying, applied extracellular field. When the cable is stimulated by a distant source, its properties are qualitatively similar to an unmyelinated fiber. Under these conditions relative threshold is proportional to the cube of the source distance and inversely proportional to the square of the fiber diameter. Electrical parameters of the model are chosen where possible, from mammalian peripheral nerve and anatomic parameters from cat auditory nerve. Several anatomic representations of the paranodal region are analyzed for their effects on the length and time constants of the fibers. Sensitivity of the model to parameter changes is studied. The linear model reliably predicts the effects of fiber size and electrode-fiber separation on threshold of cat dorsal column fibers to extracellular electrical stimulation. Images FIGURE 2 PMID:1932546

  1. Hypoglossal nerve stimulation rescue surgery after multiple multilevel procedures for obstructive sleep apnea.

    PubMed

    Strohl, Madeleine; Strohl, Kingman; Palomo, J Martin; Ponsky, Diana

    2016-01-01

    Hypoglossal nerve stimulation (HNS) is a new procedure offered for the treatment of moderate-to-severe obstructive sleep apnea (OSA) that has been shown to decrease the severity and symptoms of OSA in select patients. We report on a case of a patient with persistent symptoms and findings of OSA despite a history of multiple multilevel procedures, including an uvulopalatopharyngoplasty (UPPP) with revision, a genioglossus advancement, and a maxillomandibular advancement. The patient then underwent HNS with significant improvement of his symptoms and severity. The success of this patient's HNS surgery demonstrates that we need to examine where HNS fits into the approach to surgery for OSA. There could be benefit to considering cranial nerve stimulation earlier than conventional approaches for select patients.

  2. Topography of Synchronization of Somatosensory Evoked Potentials Elicited by Stimulation of the Sciatic Nerve in Rat

    PubMed Central

    Qu, Xuefeng; Yan, Jiaqing; Li, Xiaoli; Zhang, Peixun; Liu, Xianzeng

    2016-01-01

    Purpose: Traditionally, the topography of somatosensory evoked potentials (SEPs) is generated based on amplitude and latency. However, this operation focuses on the physical morphology and field potential-power, so it suffers from difficulties in performing identification in an objective manner. In this study, measurement of the synchronization of SEPs is proposed as a method to explore brain functional networks as well as the plasticity after peripheral nerve injury. Method: SEPs elicited by unilateral sciatic nerve stimulation in twelve adult male Sprague-Dawley (SD) rats in the normal group were compared with SEPs evoked after unilateral sciatic nerve hemisection in four peripheral nerve injured SD rats. The characterization of synchronized networks from SEPs was conducted using equal-time correlation, correlation matrix analysis, and comparison to randomized surrogate data. Eigenvalues of the correlation matrix were used to identify the clusters of functionally synchronized neuronal activity, and the participation index (PI) was calculated to indicate the involvement of each channel in the cluster. The PI value at the knee point of the PI histogram was used as a threshold to demarcate the cortical boundary. Results: Ten out of the twelve normal rats showed only one synchronized brain network. The remaining two normal rats showed one strong and one weak network. In the peripheral nerve injured group, only one synchronized brain network was found in each rat. In the normal group, all network shapes appear regular and the network is largely contained in the posterior cortex. In the injured group, the network shapes appear irregular, the network extends anteriorly and posteriorly, and the network area is significantly larger. There are considerable individual variations in the shape and location of the network after peripheral nerve injury. Conclusion: The proposed method can detect functional brain networks. Compared to the results of the traditional SEP

  3. Gait phase detection from sciatic nerve recordings in functional electrical stimulation systems for foot drop correction.

    PubMed

    Chu, Jun-Uk; Song, Kang-Il; Han, Sungmin; Lee, Soo Hyun; Kang, Ji Yoon; Hwang, Dosik; Suh, Jun-Kyo Francis; Choi, Kuiwon; Youn, Inchan

    2013-05-01

    Cutaneous afferent activities recorded by a nerve cuff electrode have been used to detect the stance phase in a functional electrical stimulation system for foot drop correction. However, the implantation procedure was difficult, as the cuff electrode had to be located on the distal branches of a multi-fascicular nerve to exclude muscle afferent and efferent activities. This paper proposes a new gait phase detection scheme that can be applied to a proximal nerve root that includes cutaneous afferent fibers as well as muscle afferent and efferent fibers. To test the feasibility of this scheme, electroneurogram (ENG) signals were measured from the rat sciatic nerve during treadmill walking at several speeds, and the signal properties of the sciatic nerve were analyzed for a comparison with kinematic data from the ankle joint. On the basis of these experiments, a wavelet packet transform was tested to define a feature vector from the sciatic ENG signals according to the gait phases. We also propose a Gaussian mixture model (GMM) classifier and investigate whether it could be used successfully to discriminate feature vectors into the stance and swing phases. In spite of no significant differences in the rectified bin-integrated values between the stance and swing phases, the sciatic ENG signals could be reliably classified using the proposed wavelet packet transform and GMM classification methods.

  4. The effect of splanchnic nerve stimulation on adrenocortical activity in conscious calves.

    PubMed Central

    Edwards, A V; Jones, C T

    1987-01-01

    1. Right adrenal and various cardiovascular responses to stimulation of the peripheral end of the right splanchnic nerve have been investigated in the presence and absence of exogenous adrenocorticotrophin, ACTH1-24, (5 ng min-1 kg-1). The adrenal-clamp technique was employed in conscious calves in which the pituitary stalk had been cauterized 3-4 days previously. 2. The I.V. infusion of ACTH1-24 increased mean plasma ACTH concentration by about 1200 pg/ml and mean right adrenal cortisol output by about 500 ng min-1 kg-1. Stimulation of the peripheral end of the right splanchnic nerve at 4 Hz for 10 min produced a further rise in cortisol output, amounting to about 400 ng min-1 kg-1 (P less than 0.01). These changes in output were reflected accurately by changes in peripheral plasma cortisol concentration. 3. Closely similar amounts of adrenaline were released in response to splanchnic nerve stimulation in the presence and absence of exogenous ACTH. In the presence of ACTH the average mean output of noradrenaline (58 +/- 2 ng min-1 kg-1) was significantly less than that of adrenaline (102 +/- 4 ng min-1 kg-1; P less than 0.001), whereas the corresponding values were not significantly different in the absence of ACTH. 4. These results also confirm the fact that the fall in adrenal vascular resistance which occurs during splanchnic nerve stimulation is substantially reduced by ACTH, as is the rise in met5-enkephalin output. 5. It is concluded that the splanchnic innervation is capable of enhancing the secretion of adrenal glucocorticoids in response to ACTH under physiological conditions in the conscious calf. PMID:3040966

  5. High-frequency stimulation selectively blocks different types of fibers in frog sciatic nerve.

    PubMed

    Joseph, Laveeta; Butera, Robert J

    2011-10-01

    Conduction block using high-frequency alternating current (HFAC) stimulation has been shown to reversibly block conduction through various nerves. However, unlike simulations and experiments on myelinated fibers, prior experimental work in our lab on the sea-slug, Aplysia, found a nonmonotonic relationship between frequency and blocking thresholds in the unmyelinated fibers. To resolve this discrepancy, we investigated the effect of HFAC waveforms on the compound action potential of the sciatic nerve of frogs. Maximal stimulation of the nerve produces a compound action potential consisting of the A-fiber and C-fiber components corresponding to the myelinated and unmyelinated fibers' response. In our study, HFAC waveforms were found to induce reversible block in the A-fibers and C-fibers for frequencies in the range of 5-50 kHz and for amplitudes from 0.1-1 mA. Although the A-fibers demonstrated the monotonically increasing threshold behavior observed in published literature, the C-fibers displayed a nonmonotonic relationship, analogous to that observed in the unmyelinated fibers of Aplysia. This differential blocking behavior observed in myelinated and unmyelinated fibers during application of HFAC waveforms has diverse implications for the fields of selective stimulation and pain management.

  6. Secretion of Growth Hormone in Response to Muscle Sensory Nerve Stimulation

    NASA Technical Reports Server (NTRS)

    Grindeland, Richard E.; Roy, R. R.; Edgerton, V. R.; Gosselink, K. L.; Grossman, E. J.; Sawchenko, P. E.; Wade, Charles E. (Technical Monitor)

    1994-01-01

    Growth hormone (GH) secretion is stimulated by aerobic and resistive exercise and inhibited by exposure to actual or simulated (bedrest, hindlimb suspension) microgravity. Moreover, hypothalamic growth hormone-releasing factor (GRF) and preproGRF mRNA are markedly decreased in spaceflight rats. These observations suggest that reduced sensory input from inactive muscles may contribute to the reduced secretion of GH seen in "0 G". Thus, the aim of this study was to determine the effect of muscle sensory nerve stimulation on secretion of GH. Fed male Wistar rats (304 +/- 23 g) were anesthetized (pentobarbital) and the right peroneal (Pe), tibial (T), and sural (S) nerves were cut. Electrical stimulation of the distal (D) or proximal (P) ends of the nerves was implemented for 15 min. to mimic the EMG activity patterns of ankle extensor muscles of a rat walking 1.5 mph. The rats were bled by cardiac puncture and their anterior pituitaries collected. Pituitary and plasma bioactive (BGH) and immunoactive (IGH) GH were measured by bioassay and RIA.

  7. Effect of stimulation of afferent renal nerves on plasma levels of vasopressin

    SciTech Connect

    Caverson, M.M.; Ciriello, J.

    1987-04-01

    Experiments were done in ..cap alpha..-chloralose-anesthetized, paralyzed and artificially ventilated cats with vagus, cervical sympathetic, aortic depressor, and carotid sinus nerves cut bilaterally to investigate the effect of afferent renal nerve (ARN) stimulation on circulating levels of vasopressin (AVP). Electrical stimulation of ARN elicited a pressor response that had two components, a primary (1/sup 0/) component locked in time with the stimulus and a secondary (2/sup 0/) component that had a long onset latency and that outlasted the stimulation period. The 1/sup 0/ and 2/sup 0/ components of the pressor response were largest at stimulation frequencies of 30 and 40 Hz, respectively. Autonomic blockage with hexamethonium bromide and atropine methylbromide abolished the 1/sup 0/ component. Administration of the vasopressin V/sub 1/-vascular receptor antagonist d(CH/sub 2/)/sub 5/ VAVP during autonomic blockade abolished the 2/sup 0/C component. Plasma concentrations of AVP measured by radioimmunoassay increased from control levels of 5.2 +/- 0.9 to 53.6 +/- 18.6 pg/ml during a 5-min period of stimulation of ARN. Plasma AVP levels measured 20-40 min after simulation were not significantly different from control values. These data demonstrate that sensory information originating in the kidney alters the release of vasopressin from the neurohypophysis and suggest that ARN are an important component of the neural circuitry involved in homeostatic mechanisms controlling arterial pressure.

  8. Studies on magnetism and bioelectromagnetics for 45 years: from magnetic analog memory to human brain stimulation and imaging.

    PubMed

    Ueno, Shoogo

    2012-01-01

    Forty-five years of studies on magnetism and bioelectromagnetics, in our laboratory, are presented. This article is prepared for the d'Arsonval Award Lecture. After a short introduction of our early work on magnetic analog memory, we review and discuss the following topics: (1) Magnetic nerve stimulation and localized transcranial magnetic stimulation (TMS) of the human brain by figure-eight coils; (2) Measurements of weak magnetic fields generated from the brain by superconducting quantum interference device (SQUID) systems, called magnetoencephalography (MEG), and its application in functional brain studies; (3) New methods of magnetic resonance imaging (MRI) for the imaging of impedance of the brain, called impedance MRI, and the imaging of neuronal current activities in the brain, called current MRI; (4) Cancer therapy and other medical treatments by pulsed magnetic fields; (5) Effects of static magnetic fields and magnetic control of cell orientation and cell growth; and (6) Effects of radio frequency magnetic fields and control of iron ion release and uptake from and into ferritins, iron cage proteins. These bioelectromagnetic studies have opened new horizons in magnetism and medicine, in particular for brain research and treatment of ailments such as depression, Parkinson's, and Alzheimer's diseases.

  9. Modeling binaural responses in the auditory brainstem to electric stimulation of the auditory nerve.

    PubMed

    Chung, Yoojin; Delgutte, Bertrand; Colburn, H Steven

    2015-02-01

    Bilateral cochlear implants (CIs) provide improvements in sound localization and speech perception in noise over unilateral CIs. However, the benefits arise mainly from the perception of interaural level differences, while bilateral CI listeners' sensitivity to interaural time difference (ITD) is poorer than normal. To help understand this limitation, a set of ITD-sensitive neural models was developed to study binaural responses to electric stimulation. Our working hypothesis was that central auditory processing is normal with bilateral CIs so that the abnormality in the response to electric stimulation at the level of the auditory nerve fibers (ANFs) is the source of the limited ITD sensitivity. A descriptive model of ANF response to both acoustic and electric stimulation was implemented and used to drive a simplified biophysical model of neurons in the medial superior olive (MSO). The model's ITD sensitivity was found to depend strongly on the specific configurations of membrane and synaptic parameters for different stimulation rates. Specifically, stronger excitatory synaptic inputs and faster membrane responses were required for the model neurons to be ITD-sensitive at high stimulation rates, whereas weaker excitatory synaptic input and slower membrane responses were necessary at low stimulation rates, for both electric and acoustic stimulation. This finding raises the possibility of frequency-dependent differences in neural mechanisms of binaural processing; limitations in ITD sensitivity with bilateral CIs may be due to a mismatch between stimulation rate and cell parameters in ITD-sensitive neurons. PMID:25348578

  10. Short-term peripheral nerve stimulation ameliorates axonal dysfunction after spinal cord injury.

    PubMed

    Lee, Michael; Kiernan, Matthew C; Macefield, Vaughan G; Lee, Bonne B; Lin, Cindy S-Y

    2015-05-01

    There is accumulating evidence that peripheral motor axons deteriorate following spinal cord injury (SCI). Secondary axonal dysfunction can exacerbate muscle atrophy, contribute to peripheral neuropathies and neuropathic pain, and lead to further functional impairment. In an attempt to ameliorate the adverse downstream effects that developed following SCI, we investigated the effects of a short-term peripheral nerve stimulation (PNS) program on motor axonal excitability in 22 SCI patients. Axonal excitability studies were undertaken in the median and common peroneal nerves (CPN) bilaterally before and after a 6-wk unilateral PNS program. PNS was delivered percutaneously over the median nerve at the wrist and CPN around the fibular head, and the compound muscle action potential (CMAP) from the abductor pollicis brevis and tibialis anterior was recorded. Stimulus intensity was above motor threshold, and pulses (450 μs) were delivered at 100 Hz with a 2-s on/off cycle for 30 min 5 days/wk. SCI patients had consistently high thresholds with a reduced CMAP consistent with axonal loss; in some patients the peripheral nerves were completely inexcitable. Nerve excitability studies revealed profound changes in membrane potential, with a "fanned-in" appearance in threshold electrotonus, consistent with membrane depolarization, and significantly reduced superexcitability during the recovery cycle. These membrane dysfunctions were ameliorated after 6 wk of PNS, which produced a significant hyperpolarizing effect. The contralateral, nonstimulated nerves remained depolarized. Short-term PNS reversed axonal dysfunction following SCI, may provide an opportunity to prevent chronic changes in axonal and muscular function, and may improve rehabilitation outcomes. PMID:25787956

  11. Computational electromagnetic methods for transcranial magnetic stimulation

    NASA Astrophysics Data System (ADS)

    Gomez, Luis J.

    Transcranial magnetic stimulation (TMS) is a noninvasive technique used both as a research tool for cognitive neuroscience and as a FDA approved treatment for depression. During TMS, coils positioned near the scalp generate electric fields and activate targeted brain regions. In this thesis, several computational electromagnetics methods that improve the analysis, design, and uncertainty quantification of TMS systems were developed. Analysis: A new fast direct technique for solving the large and sparse linear system of equations (LSEs) arising from the finite difference (FD) discretization of Maxwell's quasi-static equations was developed. Following a factorization step, the solver permits computation of TMS fields inside realistic brain models in seconds, allowing for patient-specific real-time usage during TMS. The solver is an alternative to iterative methods for solving FD LSEs, often requiring run-times of minutes. A new integral equation (IE) method for analyzing TMS fields was developed. The human head is highly-heterogeneous and characterized by high-relative permittivities (107). IE techniques for analyzing electromagnetic interactions with such media suffer from high-contrast and low-frequency breakdowns. The novel high-permittivity and low-frequency stable internally combined volume-surface IE method developed. The method not only applies to the analysis of high-permittivity objects, but it is also the first IE tool that is stable when analyzing highly-inhomogeneous negative permittivity plasmas. Design: TMS applications call for electric fields to be sharply focused on regions that lie deep inside the brain. Unfortunately, fields generated by present-day Figure-8 coils stimulate relatively large regions near the brain surface. An optimization method for designing single feed TMS coil-arrays capable of producing more localized and deeper stimulation was developed. Results show that the coil-arrays stimulate 2.4 cm into the head while stimulating 3

  12. Non-Invasive Vagus Nerve Stimulation as Treatment for Trigeminal Allodynia

    PubMed Central

    Oshinsky, Michael L.; Murphy, Angela L.; Hekierski, Hugh; Cooper, Marnie; Simon, Bruce J.

    2014-01-01

    Implanted vagus nerve stimulation (VNS) has been used to treat seizures and depression. In this study, we explore the mechanism of action of non-invasive vagus nerve stimulation (nVNS) for the treatment of trigeminal allodynia. Rats were repeatedly infused with inflammatory mediators directly onto the dura, which leads to chronic trigeminal allodynia. nVNS for 2min decreases periorbital sensitivity in rats with periorbital trigeminal allodynia for up to 3.5hr after stimulation. Using microdialysis, we quantified levels of extracellular neurotransmitters in the trigeminal nucleus caudalis (TNC). Allodynic rats showed a 7.7±0.9 fold increase in extracellular glutamate in the TNC following i.p. administration of the chemical headache trigger, glyceryl trinitrate (GTN; 0.1mg/kg). Allodynic rats, which received nVNS, had only a 2.3±0.4 fold increase in extracellular glutamate following GTN similar to the response in control naive rats. When nVNS was delayed until 120min after GTN treatment, the high levels of glutamate in the TNC were reversed following nVNS. The nVNS stimulation parameters used in this study did not produce significant changes in blood pressure or heart rate. These data suggest that nVNS may be used to treat trigeminal allodynia. PMID:24530613

  13. Transcutaneous Vagus Nerve Stimulation (tVNS) does not increase prosocial behavior in Cyberball

    PubMed Central

    Sellaro, Roberta; Steenbergen, Laura; Verkuil, Bart; van IJzendoorn, Marinus H.; Colzato, Lorenza S.

    2015-01-01

    Emerging research suggests that individuals experience vicarious social pain (i.e., ostracism). It has been proposed that observing ostracism increases activity in the insula and in the prefrontal cortex (PFC), two key brain regions activated by directly experiencing ostracism. Here, we assessed the causal role of the insula and PFC in modulating neural activity in these areas by applying transcutaneous Vagus Nerve Stimulation (tVNS), a new non-invasive and safe method to stimulate the vagus nerve that has been shown to activate the insula and PFC. A single-blind, sham-controlled, within-subjects design was used to assess the effect of on-line (i.e., stimulation overlapping with the critical task) tVNS in healthy young volunteers (n = 24) on the prosocial Cyberball game, a virtual ball-tossing game designed to measure prosocial compensation of ostracism. Active tVNS did not increase prosocial helping behavior toward an ostracized person, as compared to sham (placebo) stimulation. Corroborated by Bayesian inference, we conclude that tVNS does not modulate reactions to vicarious ostracism, as indexed by performance in a Cyberball game. PMID:25972825

  14. Sensory feedback by peripheral nerve stimulation improves task performance in individuals with upper limb loss using a myoelectric prosthesis

    NASA Astrophysics Data System (ADS)

    Schiefer, Matthew; Tan, Daniel; Sidek, Steven M.; Tyler, Dustin J.

    2016-02-01

    Objective. Tactile feedback is critical to grip and object manipulation. Its absence results in reliance on visual and auditory cues. Our objective was to assess the effect of sensory feedback on task performance in individuals with limb loss. Approach. Stimulation of the peripheral nerves using implanted cuff electrodes provided two subjects with sensory feedback with intensity proportional to forces on the thumb, index, and middle fingers of their prosthetic hand during object manipulation. Both subjects perceived the sensation on their phantom hand at locations corresponding to the locations of the forces on the prosthetic hand. A bend sensor measured prosthetic hand span. Hand span modulated the intensity of sensory feedback perceived on the thenar eminence for subject 1 and the middle finger for subject 2. We performed three functional tests with the blindfolded subjects. First, the subject tried to determine whether or not a wooden block had been placed in his prosthetic hand. Second, the subject had to locate and remove magnetic blocks from a metal table. Third, the subject performed the Southampton Hand Assessment Procedure (SHAP). We also measured the subject’s sense of embodiment with a survey and his self-confidence. Main results. Blindfolded performance with sensory feedback was similar to sighted performance in the wooden block and magnetic block tasks. Performance on the SHAP, a measure of hand mechanical function and control, was similar with and without sensory feedback. An embodiment survey showed an improved sense of integration of the prosthesis in self body image with sensory feedback. Significance. Sensory feedback by peripheral nerve stimulation improved object discrimination and manipulation, embodiment, and confidence. With both forms of feedback, the blindfolded subjects tended toward results obtained with visual feedback.

  15. Impaired sensory conduction in a mixed nerve induced by high frequency stimulation of the muscle fibres. An experimental study in cats.

    PubMed

    Miyauchi, A; Matsuda, H; Shimazu, A; Nakata, N; Seki, M

    1993-12-01

    To see if symptoms such as sensory disturbance or numbness worsen during exercise as is thought to occur in entrapment neuropathy, we studied the interaction between sensory and muscle nerve fibres in a mixed nerve in cats. Stimulation electrodes were placed on both the deep (muscle) and superficial (sensory) branch of the radial nerve at the elbow. High frequency stimulation at 100 Hz was applied to one branch for five minutes and the nerve action potential of the other branch was recorded at the axilla where the radial nerve is mixed. The stimulation decreased the amplitude of the nerve action potential and prolonged its latency. Recovery from these changes was gradual, and changes were the same whichever branch was stimulated. When a cat's leg was made ischaemic, the changes were more pronounced. The changes in the nerve action potential may have arisen from ischaemia in the nerve, possibly caused by high frequency stimulation. PMID:8159937

  16. Nonpharmacologic care for patients with Lennox-Gastaut syndrome: ketogenic diets and vagus nerve stimulation.

    PubMed

    Kossoff, Eric H W; Shields, W Donald

    2014-09-01

    Individuals with Lennox-Gastaut syndrome (LGS) often do not respond to or become resistant to pharmacologic treatments. Ketogenic diets (KDs) and vagus nerve stimulation (VNS) are nonpharmacologic treatment options for these intractable patients. The classic KD, a high-fat, low-carbohydrate diet with 90% of calories derived from fat, has been used in the treatment of seizures for >90 years. About half of patients with LGS respond to the KD with a >50% reduction in seizures and some patients may achieve a >90% reduction. Vagus nerve stimulation therapy involves a surgically implanted generator that delivers intermittent electrical stimuli to the brain via an electrode wrapped around the left vagus nerve. It is utilized as adjunctive therapy for patients with drug-resistant epilepsy (including patients with LGS) who are not suitable candidates for resective surgery. Similar to the KD, about half of LGS patients respond to VNS therapy, with a >50% reduction in seizures, and the response may improve over time. Both the KD and VNS are options for patients with LGS.

  17. A computational model for the stimulation of rat sciatic nerve using a transverse intrafascicular multichannel electrode.

    PubMed

    Raspopovic, Stanisa; Capogrosso, Marco; Micera, Silvestro

    2011-08-01

    Neuroprostheses based on electrical stimulation could potentially help disabled persons. They are based on neural interface that aim at creating an intimate contact with neural cells. The efficacy of neuroprostheses can be improved by increasing the selectivity of the neural interfaces used to stimulate specific subsets of cells. Selectivity is strongly influenced by interface design. Computer models can be useful for exploring the high dimensional space of design parameters with the aim to provide guidelines for the development of more efficient electrodes, with minimal animal use and optimization of manufacturing processes. The purpose of this study was to implement a realistic model of the performance of a transverse intrafascicular multichannel electrode (TIME) implanted into the rat sciatic nerve. A realistic finite element method (FEM) model was developed taking into account the anatomical and physiological features of the rat sciatic nerve. Electric potentials were calculated and interpolated voltages were applied to the model of a rat sciatic nerve axon, based on experimental biophysical data. Results indicate that high intra-fascicular and inter-fascicular selectivity values with low current levels can be achieved with TIMEs. The selectivity of TIMEs was also compared to an extraneural electrode, showing that higher selectivity with less current can be obtained. Using this model, the robustness of electrode performances for translational and rotational displacements were evaluated.

  18. Plasma renin activity during hypotensive responses to electrical stimulation carotid sinus nerves in conscious dogs.

    PubMed

    Peters, T K; Kaczmarczyk, G

    1994-01-01

    1. The interaction of electrical stimulation of the carotid sinus nerves (carotid sinus nerve stimulation, CSNS) with mechanisms of renin release was studied in conscious and unrestrained resting beagle dogs receiving a standardized diet (sodium intake, 4.5 mmol/kg bodyweight (bw); water intake, 91 mL/kg bw). 2. By CSNS, mean arterial blood pressure (MAP) was lowered for periods of 20 min to levels between 101 +/- 4 and 56 +/- 5 mmHg. 3. In another group of conscious dogs, renal perfusion pressure (RPP) was lowered to 95 +/- 4 mmHg for periods of 20 min by partial suprarenal aortic occlusion in order to assess the influence of a reduced RPP on plasma renin activity (PRA) without concomitant CSNS. 4. During CSNS, PRA increased markedly (> 100%) only when MAP was reduced below 75 mmHg. 5. With aortic constriction and an RPP of 95 mmHg, the increase in PRA was 955%, which is more than three-fold higher than the increase in PRA during CSNS at MAP levels < 65 mmHg (314%). 6. The observed responses indirectly support the hypothesis that basal activity in efferent renal nerve discharge is present even at rest and can be inhibited by CSNS, and furthermore suggests that CSNS attenuated the pressure-dependent renin release.

  19. Comparision of nerve stimulator and ultrasonography as the techniques applied for brachial plexus anesthesia

    PubMed Central

    2011-01-01

    Background Brachial plexus block is useful for upper extremity surgery, and many techniques are available. The aim of our study was to compare the efficacy of axillary brachial plexus block using an ultrasound technique to the peripheral nerve stimulation technique. Methods 60 patients scheduled for surgery of the forearm or hand were randomly allocated into two groups (n = 30 per group). For Group 1; US, and for Group 2 PNS was applied. The quality and the onset of the sensorial and motor blockade were assessed. The sensorial blockade, motor blockade time and quality of blockade were compared among the cases. Results The time needed to perform the axillary brachial plexus block averaged is similar in both groups (p > 0.05). Although not significant statistically, it was observed that the sensory block had formed earlier in Group 1 (p > 0.05). But the degree of motor blockade was intenser in Group 1 than in Group 2 (p < 0.05). Conclusions Ultrasound offers a new possibility for identifiying the nerves of the brachial plexus for regional anesthesia. The ultrasound-guided axillary brachial plexus block is a safe method with faster onset time and better quality of motor blockade compared to peripheral nerve stimulation technique. PMID:21255404

  20. Synaptic Plasticity after Chemical Deafening and Electrical Stimulation of the Auditory Nerve in Cats

    PubMed Central

    Ryugo, D.K.; Baker, C.A.; Montey, K.L.; Chang, L.Y.; Coco, A.; Fallon, J.B.; Shepherd, R.K.

    2010-01-01

    The effects of deafness on brain structure and function have been studied using animal models of congenital deafness that include surgical ablation of the organ of Corti, acoustic trauma, ototoxic drugs, and hereditary deafness. This report describes the morphologic plasticity of auditory nerve synapses in response to ototoxic deafening and chronic electrical stimulation of the auditory nerve. Normal kittens were deafened by neonatal administration of neomycin that eliminated auditory receptor cells. Some of these cats were raised deaf, whereas others were chronically implanted with cochlear electrodes at two months of age and electrically stimulated for up to 12 months. The large endings of the auditory nerve, endbulbs of Held, were studied because they hold a key position in the timing pathway for sound localization, are readily identifiable, and exhibit deafness-associated abnormalities. Compared to normal hearing cats, synapses of ototoxically deafened cats displayed expanded postsynaptic densities, a decrease in synaptic vesicle (SV) density, and a reduction in the somatic size of spherical bushy cells (SBCs). When compared to normal hearing cats, endbulbs of ototoxically deafened cats that received cochlear stimulation expressed postsynaptic densities (PSDs) that were statistically identical in size, showed a 32.8% reduction in SV density, and whose target SBCs had a 25.5% reduction in soma area. These results demonstrate that electrical stimulation via a cochlear implant in chemically-deafened cats preserves PSD size but not other aspects of synapse morphology. The results further suggest that the effects of ototoxic deafness are not identical to those of hereditary deafness. PMID:20127807

  1. Auditory stimulation affects renal sympathetic nerve activity and blood pressure in rats.

    PubMed

    Nakamura, Takuo; Tanida, Mamoru; Niijima, Akira; Hibino, Hiroshi; Shen, Jiao; Nagai, Katsuya

    2007-04-12

    Here, we examined the effects of auditory stimulation at 50 dB with white noise (WN) or music (Traeumerei [TM] by Schumann or Etude by Chopin) on renal sympathetic nerve activity (RSNA) and BP in urethane-anesthetized rats. Auditory stimulation with TM, but not with WN or the Etude, significantly decreased RSNA and BP. Complete bilateral destruction of the cochleae and bilateral lesions of the auditory cortex (AuC) eliminated the effects of TM stimulation on RSNA and BP, but bilateral lesions of primary somatosensory cortex (S1C) had no effect. Bilateral lesions of the hypothalamic suprachiasmatic nucleus (SCN) or intracerebral administration of thioperamide, a histaminergic H3 receptor antagonist, also abolished TM-induced decreases in RSNA and BP. These findings suggest that exposure to music can decrease RSNA and BP through the auditory pathway, histaminergic neurons, and the SCN.

  2. Transcranial magnetic stimulation (TMS) inhibits cortical dendrites.

    PubMed

    Murphy, Sean C; Palmer, Lucy M; Nyffeler, Thomas; Müri, René M; Larkum, Matthew E

    2016-03-18

    One of the leading approaches to non-invasively treat a variety of brain disorders is transcranial magnetic stimulation (TMS). However, despite its clinical prevalence, very little is known about the action of TMS at the cellular level let alone what effect it might have at the subcellular level (e.g. dendrites). Here, we examine the effect of single-pulse TMS on dendritic activity in layer 5 pyramidal neurons of the somatosensory cortex using an optical fiber imaging approach. We find that TMS causes GABAB-mediated inhibition of sensory-evoked dendritic Ca(2+) activity. We conclude that TMS directly activates fibers within the upper cortical layers that leads to the activation of dendrite-targeting inhibitory neurons which in turn suppress dendritic Ca(2+) activity. This result implies a specificity of TMS at the dendritic level that could in principle be exploited for investigating these structures non-invasively.

  3. Gaussian versus flat-top spatial beam profiles for optical stimulation of the prostate nerves

    NASA Astrophysics Data System (ADS)

    Tozburun, Serhat; Lagoda, Gwen A.; Burnett, Arthur L.; Fried, Nathaniel M.

    2010-02-01

    The cavernous nerves (CN) course along the prostate surface and are responsible for erectile function. Improved identification and preservation of the CN's is critical to maintaining sexual potency after prostate cancer surgery. Noncontact optical nerve stimulation (ONS) of the CN's was recently demonstrated in a rat model, in vivo, as a potential alternative to electrical nerve stimulation (ENS) for identification of the CN's during prostate surgery. However, the therapeutic window for ONS is narrow, so optimal design of the fiber optic delivery system is critical for safe, reproducible stimulation. This study describes modeling, assembly, and testing of an ONS probe for delivering a small, collimated, flat-top laser beam for uniform CN stimulation. A direct comparison of the magnitude and response time of the intracavernosal pressure (ICP) for both Gaussian and flat-top spatial beam profiles was performed. Thulium fiber laser radiation (λ=1870 nm) was delivered through a 200-μm fiber, with distal fiber tip chemically etched to convert a Gaussian to flat-top beam profile. The laser beam was collimated to a 1-mm-diameter spot using an aspheric lens. Computer simulations of light propagation were used to optimize the probe design. The 10-Fr (3.4-mm-OD) laparoscopic probe provided a constant radiant exposure at the CN surface. The probe was tested in four rats, in vivo. ONS of the CN's was performed with a 1-mm-diameter spot, 5-ms pulse duration, and pulse rate of 20 Hz for a duration of 15-30 s. The flat-top laser beam profile consistently produced a faster and higher ICP response at a lower radiant exposure than the Gaussian beam profile due, in part, to easier alignment of the more uniform beam with nerve. The threshold for ONS was approximately 0.14 J/cm2, corresponding to a temperature increase of 6-8°C at the CN surface after a stimulation time of 15 s. With further development, ONS may be used as a diagnostic tool for identification of CN's during prostate

  4. Optical Parameter Variability in Laser Nerve Stimulation: A Study of Pulse Duration, Repetition Rate, and Wavelength

    PubMed Central

    Walsh, Joseph T.; Jansen, E. Duco; Bendett, Mark; Webb, Jim; Ralph, Heather; Richter, Claus-Peter

    2012-01-01

    Pulsed lasers can evoke neural activity from motor as well as sensory neurons in vivo. Lasers allow more selective spatial resolution of stimulation than the conventional electrical stimulation. To date, few studies have examined pulsed, mid-infrared laser stimulation of nerves and very little of the available optical parameter space has been studied. In this study, a pulsed diode laser, with wavelength between 1.844–1.873 μm, was used to elicit compound action potentials (CAPs) from the auditory system of the gerbil. We found that pulse durations as short as 35 μs elicit a CAP from the cochlea. In addition, repetition rates up to 13 Hz can continually stimulate cochlear spiral ganglion cells for extended periods of time. Varying the wavelength and, therefore, the optical penetration depth, allowed different populations of neurons to be stimulated. The technology of optical stimulation could significantly improve cochlear implants, which are hampered by a lack of spatial selectivity. PMID:17554829

  5. Effects of electrode geometry and combination on nerve fibre selectivity in spinal cord stimulation.

    PubMed

    Holsheimer, J; Struijk, J J; Tas, N R

    1995-09-01

    The differential effects of the geometry of a rostrocaudal array of electrode contacts on dorsal column fibre and dorsal root fibre activation in spinal cord stimulation are analysed theoretically. 3-D models of the mid-cervical and mid-thoracic vertebral areas are used for the computation of stimulation induced field potentials, whereas a cable model of myelinated nerve fibre is used for the calculation of the excitation thresholds of large dorsal column and dorsal root fibres. The size and spacing of 2-D rectangular electrode contacts are varied while mono-, bi- and tripolar stimulation are applied. The model predicts that the highest preferential stimulation of dorsal root fibres is obtained in monopolar stimulation with a large cathode, whereas dorsal column fibre preference is highest in tripolar stimulation with small contacts and small contact spacings. Fibre type preference is most sensitive to variations of rostrocaudal contact size and least sensitive to variations of lateral contact size. Dorsal root fibre preference is increased and sensitivity to lead geometry is reduced as the distance from contacts to spinal cord is increased.

  6. Jak/Stat Signaling Stimulates Zebrafish Optic Nerve Regeneration and Overcomes the Inhibitory Actions of Socs3 and Sfpq

    PubMed Central

    Elsaeidi, Fairouz; Bemben, Michael A.; Zhao, Xiao-Feng

    2014-01-01

    The regenerative failure of mammalian optic axons is partly mediated by Socs3-dependent inhibition of Jak/Stat signaling (Smith et al., 2009, 2011). Whether Jak/Stat signaling is part of the normal regenerative response observed in animals that exhibit an intrinsic capacity for optic nerve regeneration, such as zebrafish, remains unknown. Nor is it known whether the repression of regenerative inhibitors, such as Socs3, contributes to the robust regenerative response of zebrafish to optic nerve damage. Here we report that Jak/Stat signaling stimulates optic nerve regeneration in zebrafish. We found that IL-6 family cytokines, acting via Gp130-coupled receptors, stimulate Jak/Stat3 signaling in retinal ganglion cells after optic nerve injury. Among these cytokines, we found that CNTF, IL-11, and Clcf1/Crlf1a can stimulate optic axon regrowth. Surprisingly, optic nerve injury stimulated the expression of Socs3 and Sfpq (splicing factor, proline/glutamine rich) that attenuate optic nerve regeneration. These proteins were induced in a Jak/Stat-dependent manner, stimulated each other's expression and suppressed the expression of regeneration-associated genes. In vivo, the injury-dependent induction of Socs3 and Sfpq inhibits optic nerve regeneration but does not block it. We identified a robust induction of multiple cytokine genes in zebrafish retinal ganglion cells that may contribute to their ability to overcome these inhibitory factors. These studies not only identified mechanisms underlying optic nerve regeneration in fish but also suggest new molecular targets for enhancing optic nerve regeneration in mammals. PMID:24523552

  7. Effect of somatic nerve stimulation on the kidney in intact, vagotomized and carotid sinus-denervated rats.

    PubMed

    Davis, G; Johns, E J

    1991-01-01

    1. The influence of cardiopulmonary and arterial baroreceptors on the renal nerve-dependent functional responses of the kidney to electrical stimulation of somatic afferent nerves was studied in pentobarbitone-anaesthetized rats. 2. Electrical stimulation of the left brachial nerve plexus at 3 Hz, 0.2 ms and 15 V in the intact animals increased blood pressure by 22%, and while renal perfusion pressure was maintained at pre-stimulus levels, renal blood flow and glomerular filtration rate decreased by 14 and 22% respectively. At the same time urine flow rate and absolute and fractional sodium excretion decreased by 36, 42 and 27% respectively. In animals subjected to acute renal nerve section these renal functional responses could not be elicited. 3. Following bilateral vagotomy the systemic and renal haemodynamic responses to brachial nerve stimulation were similar to the intact group. However, urine flow rate and absolute and fractional sodium excretions decreased by 50, 59 and 47% respectively, responses which were significantly greater than in the intact group. 4. In a group of rats in which the carotid sinus nerves had been sectioned, stimulation of the brachial plexus caused reductions of renal blood flow and glomerular filtration rate of the same magnitude as in the intact group; however, urine flow rate and absolute and fractional sodium excretion fell by 51, 60 and 48%, respectively, which were significantly larger than in the intact group. 5. These results demonstrate that the afferent nerve information arising from muscle joints and skin and carried via the brachial plexus caused reflex renal nerve-dependent reductions in renal haemodynamics and an antidiuresis and antinatriuresis. The cardiopulmonary and carotid sinus baroreceptors exert a tonic inhibitory action on these reflex renal responses insofar as they appeared to attenuate the antidiuretic and antinatriuretic responses to somatic afferent nerve stimulation.

  8. Permanent implantation of peripheral nerve stimulator for combat injury-related ilioinguinal neuralgia.

    PubMed

    Banh, Diem Phuc T; Moujan, Pablo M; Haque, Quazi; Han, Tae-Hyung

    2013-01-01

    A peripheral nerve stimulator (PNS) can be an alternative for long-term pain relief refractory to conventional therapeutic modalities. We present a case of chronic incapacitating ilioinguinal neuralgia, which was successfully managed with permanent implantation of a peripheral nerve stimulator. A 26-year-old active duty African American man was referred to the University Pain Clinic with left ilioinguinal neuralgia due to shrapnel injury during his military service 6 years prior to his visit. Most of the shrapnel were surgically removed, but the patient subsequently developed left lower abdominal pain. Multiple surgeries, including inguinal herniorrhaphy, varicocelectomy, and orchiectomy, failed to provide satisfactory relief of his neuralgia. Other therapies tried resulting in limited outcomes were multiple ilioinguinal nerve blocks and cryoanalgesia. A trial of PNS was successful and the implantation of permanent leads was carried out. At his 3-month visit, the patient reported to have minimal pain, was tapered off oral analgesics, was able to return to work, and had resumed his normal daily activities. Recent technological advances in programming software and surgical techniques have led to renewed interest in PNS for the treatment of chronic refractory peripheral nerve injury. Despite our limited understanding of its exact mechanism of action, it can be considered as a therapeutic potential for a few carefully selected, intractable cases. Its minimally invasive and reversible features make PNS a favorable option for these patients. The stringent and rigorous screening procedures for suitable candidacy, documentation of previously failed treatments, psychiatric evaluation, and 3-5 days of preplacement trial, improve the success rate. PMID:24284860

  9. Electroencephalogram activity induced by magnetic stimulation on heart meridian.

    PubMed

    Jo, Han-Gue; Jo, Gi-Ho

    2011-05-16

    Many studies on the effects of acupuncture on brain activity have been concerned with the stimulation of specific acu-points. However, research on brain activity with the stimulation of the body-meridian line is still quite novel. The hypothesis of the present study is that heart meridian stimulations with different directions of line-magnet poles would elicit different effects on EEG activity. Twenty-three healthy young adults between the age of 19 and 22 years old participated in the experiment. Two tiny NEO line-magnets were applied to stimulate the heart meridian. EEG activities were changed significantly between different treatments on the heart meridian using line-magnet with different directions of magnetic poles (p<0.05). The present study shows that the stimulation of the heart meridian with the line-magnets has an effect on brain activity associated with the direction of the line-magnet pole.

  10. Application of implantable wireless biomicrosystem for monitoring nerve impedance of rat after sciatic nerve injury.

    PubMed

    Li, Yu-Ting; Peng, Chih-Wei; Chen, Lung-Tai; Lin, Wen-Shan; Chu, Chun-Hsun; Chen, Jia-Jin Jason

    2013-01-01

    Electrical stimulation is usually applied percutaneously for facilitating peripheral nerve regeneration. However, few studies have conducted long-term monitoring of the condition of nerve regeneration. This study implements an implantable biomicrosystem for inducing pulse current for aiding nerve repair and monitoring the time-course changes of nerve impedance for assessing nerve regeneration in sciatic nerve injury rat model. For long-term implantation, a transcutaneous magnetic coupling technique is adopted for power and data transmission. For in vivo study, the implanted module was placed in the rat's abdomen and the cuff electrode was wrapped around an 8-mm sciatic nerve gap of the rat for nerve impedance measurement for 42 days. One group of animals received monophasic constant current via the cuff electrode and a second group had no stimulation between days 8-21. The nerve impedance increased to above 150% of the initial value in the nerve regeneration groups with and without stimulation whereas the group with no nerve regeneration increased to only 113% at day 42. The impedance increase in nerve regeneration groups can be observed before evident functional recovery. Also, the nerve regeneration group that received electrical stimulation had relatively higher myelinated fiber density than that of no stimulation group, 20686 versus 11417 fiber/mm (2). The developed implantable biomicrosystem is proven to be a useful experimental tool for long-term stimulation in aiding nerve fiber growth as well as impedance assessment for understanding the time-course changes of nerve regeneration. PMID:23060343

  11. Sensorimotor integration in Complex Regional Pain Syndrome: a transcranial magnetic stimulation study.

    PubMed

    Turton, Ailie J; McCabe, Candida S; Harris, Nigel; Filipovic, Sasa R

    2007-02-01

    There is evidence that patients with Complex Regional Pain Syndrome (CRPS) have altered central sensorimotor processing. Sensory input can influence motor output either through indirect pathways or through direct connections from the sensory to motor cortex. The purpose of this study was to investigate sensorimotor interaction via direct connections in patients with CRPS and to compare the results with normal subjects'. Direct short-latency sensory-motor interaction was evaluated in eight patients with CRPS1 affecting a hand. Modulation of EMG responses to transcranial magnetic stimulation (TMS) induced by concomitant median nerve stimulation was measured, the so-called, short-latency afferent inhibition (SAI). Results were compared with eight normal subjects who were age and sex matched with the patients. As expected, all the normal subjects' EMG responses to TMS with median nerve stimulation were smaller than responses to TMS alone. In seven of the eight CRPS patients EMG responses to TMS were suppressed when paired with median nerve stimulation. Only one CRPS patient's results showed no suppression of EMG responses. These results suggest that the disease mechanisms of CRPS1 do not typically affect the direct neural circuit between sensory and motor cortex and that normal sensorimotor interaction is occurring via this route.

  12. Coordinated, multi-joint, fatigue-resistant feline stance produced with intrafascicular hind limb nerve stimulation

    NASA Astrophysics Data System (ADS)

    Normann, R. A.; Dowden, B. R.; Frankel, M. A.; Wilder, A. M.; Hiatt, S. D.; Ledbetter, N. M.; Warren, D. A.; Clark, G. A.

    2012-04-01

    The production of graceful skeletal movements requires coordinated activation of multiple muscles that produce torques around multiple joints. The work described herein is focused on one such movement, stance, that requires coordinated activation of extensor muscles acting around the hip, knee and ankle joints. The forces evoked in these muscles by external stimulation all have a complex dependence on muscle length and shortening velocities, and some of these muscles are biarticular. In order to recreate sit-to-stand maneuvers in the anesthetized feline, we excited the hind limb musculature using intrafascicular multielectrode stimulation (IFMS) of the muscular branch of the sciatic nerve, the femoral nerve and the main branch of the sciatic nerve. Stimulation was achieved with either acutely or chronically implanted Utah Slanted Electrode Arrays (USEAs) via subsets of electrodes (1) that activated motor units in the extensor muscles of the hip, knee and ankle joints, (2) that were able to evoke large extension forces and (3) that manifested minimal coactivation of the targeted motor units. Three hind limb force-generation strategies were investigated, including sequential activation of independent motor units to increase force, and interleaved or simultaneous IFMS of three sets of six or more USEA electrodes that excited the hip, knee and ankle extensors. All force-generation strategies evoked stance, but the interleaved IFMS strategy also reduced muscle fatigue produced by repeated sit-to-stand maneuvers compared with fatigue produced by simultaneous activation of different motor neuron pools. These results demonstrate the use of interleaved IFMS as a means to recreate coordinated, fatigue-resistant multi-joint muscle forces in the unilateral hind limb. This muscle activation paradigm could provide a promising neuroprosthetic approach for the restoration of sit-to-stand transitions in individuals who are paralyzed by spinal cord injury, stroke or disease.

  13. Episodic phrenic-inhibitory vagus nerve stimulation paradoxically induces phrenic long-term facilitation in rats

    PubMed Central

    Zhang, Yi; McGuire, Michelle; White, David P; Ling, Liming

    2003-01-01

    All respiratory long-term facilitation (LTF) is induced by inspiratory-excitatory stimulation, suggesting that LTF needs inspiratory augmentation and is the result of a Hebbian mechanism (coincident pre- and post-synaptic activity strengthens synapses). The present study examined the long-term effects of episodic inspiratory-inhibitory vagus nerve stimulation (VNS) on phrenic nerve activity. We hypothesized that episodic VNS would induce phrenic long-term depression. The results are compared with those obtained following serotonin receptor antagonism or episodic carotid sinus nerve stimulation (CSNS). Integrated phrenic neurograms were measured before, during and after three episodes of 5 min VNS (50 Hz, 0.1 ms), each separated by a 5 min interval, at a low (˜50 μA), medium (˜200 μA) or high (˜500 μA) stimulus intensity in anaesthetized, vagotomized, neuromuscularly blocked and artificially ventilated rats. Medium- and high-intensity VNS eliminated rhythmic phrenic activity during VNS, while low-intensity VNS only reduced phrenic burst frequency. At 60 min post-VNS, phrenic amplitude was higher than baseline (35 ± 5 % above baseline, mean ± S.E.M., P < 0.05) in the high-intensity group but not in the low- (−4 ± 4 %) or medium-intensity groups (−10 ± 15 %), or in the high-intensity with methysergide group (4 mg kg−1, I.P.) (−11 ± 5 %). These data, which are inconsistent with our hypothesis, indicate that phrenic-inhibitory VNS induces a serotonin-dependent phrenic LTF similar to that induced by phrenic-excitatory CSNS (33 ± 7 %) and may require activation of high-threshold afferent fibres. These data also suggest that the synapses on phrenic motoneurons do not use the Hebbian mechanism in this LTF, as these motoneurons were suppressed during VNS. PMID:12872010

  14. Haemodynamic Responses to Selective Vagal Nerve Stimulation under Enalapril Medication in Rats

    PubMed Central

    Gierthmuehlen, Mortimer; Stieglitz, Thomas; Zentner, Josef; Plachta, Dennis T. T.

    2016-01-01

    Selective vagal nerve stimulation (sVNS) has been demonstrated to lower blood pressure (BP) in rats without causing major side effects. This method might be adapted for the treatment of therapy-resistant hypertension in patients. Converting enzyme inhibitors (CEIs) are among the first drugs that are administered for arterial hypertension and prominently reduce BP primarily by interacting with the renin-angiotensin system of the kidneys. Beyond the reduction of BP, CEI have a positive effect on the survival rate after myocardial infarction; they reduce the rates of stroke and improve the neurohormonal status in heart-failure patients. If sVNS might be introduced as a therapy against resistant hypertension, patients will at least partially stay on their CEI medication. It is therefore the aim of this study to investigate the influence of the CEI enalapril on the haemodynamic and respiratory effects of sVNS. In 10 male Wistar rats, a polyimide-based multichannel-cuff-electrode was placed around the vagal nerve bundle to selectively stimulate the aortic depressor nerve fibres. Stimulation parameters were adapted to the thresholds of the individual animals and included repetition frequencies between 30 and 50 Hz, amplitudes of 0.5 to 1.5 mA and pulse widths between 0.4 ms and 1.0 ms. BP responses were detected with a microtip transducer in the left carotid artery, and electrocardiography was recorded with subcutaneous electrodes. After intravenous administration of enalapril (2 mg/kg bodyweight), the animals’ mean arterial blood pressures (MAPs) decreased significantly, while the heart rates (HRs) were not significantly influenced. The effects of sVNS on BP and HR were attenuated by enalapril but were still present. We conclude that sVNS can lower the MAP during enalapril treatment without relevant side effects. PMID:26766419

  15. Haemodynamic Responses to Selective Vagal Nerve Stimulation under Enalapril Medication in Rats.

    PubMed

    Gierthmuehlen, Mortimer; Stieglitz, Thomas; Zentner, Josef; Plachta, Dennis T T

    2016-01-01

    Selective vagal nerve stimulation (sVNS) has been demonstrated to lower blood pressure (BP) in rats without causing major side effects. This method might be adapted for the treatment of therapy-resistant hypertension in patients. Converting enzyme inhibitors (CEIs) are among the first drugs that are administered for arterial hypertension and prominently reduce BP primarily by interacting with the renin-angiotensin system of the kidneys. Beyond the reduction of BP, CEI have a positive effect on the survival rate after myocardial infarction; they reduce the rates of stroke and improve the neurohormonal status in heart-failure patients. If sVNS might be introduced as a therapy against resistant hypertension, patients will at least partially stay on their CEI medication. It is therefore the aim of this study to investigate the influence of the CEI enalapril on the haemodynamic and respiratory effects of sVNS. In 10 male Wistar rats, a polyimide-based multichannel-cuff-electrode was placed around the vagal nerve bundle to selectively stimulate the aortic depressor nerve fibres. Stimulation parameters were adapted to the thresholds of the individual animals and included repetition frequencies between 30 and 50 Hz, amplitudes of 0.5 to 1.5 mA and pulse widths between 0.4 ms and 1.0 ms. BP responses were detected with a microtip transducer in the left carotid artery, and electrocardiography was recorded with subcutaneous electrodes. After intravenous administration of enalapril (2 mg/kg bodyweight), the animals' mean arterial blood pressures (MAPs) decreased significantly, while the heart rates (HRs) were not significantly influenced. The effects of sVNS on BP and HR were attenuated by enalapril but were still present. We conclude that sVNS can lower the MAP during enalapril treatment without relevant side effects.

  16. Alternating Current Stimulation for Vision Restoration after Optic Nerve Damage: A Randomized Clinical Trial

    PubMed Central

    Schittkowski, Michael P.; Antal, Andrea; Ambrus, Géza Gergely; Paulus, Walter; Dannhauer, Moritz; Michalik, Romualda; Mante, Alf; Bola, Michal; Lux, Anke; Kropf, Siegfried; Brandt, Stephan A.; Sabel, Bernhard A.

    2016-01-01

    Background Vision loss after optic neuropathy is considered irreversible. Here, repetitive transorbital alternating current stimulation (rtACS) was applied in partially blind patients with the goal of activating their residual vision. Methods We conducted a multicenter, prospective, randomized, double-blind, sham-controlled trial in an ambulatory setting with daily application of rtACS (n = 45) or sham-stimulation (n = 37) for 50 min for a duration of 10 week days. A volunteer sample of patients with optic nerve damage (mean age 59.1 yrs) was recruited. The primary outcome measure for efficacy was super-threshold visual fields with 48 hrs after the last treatment day and at 2-months follow-up. Secondary outcome measures were near-threshold visual fields, reaction time, visual acuity, and resting-state EEGs to assess changes in brain physiology. Results The rtACS-treated group had a mean improvement in visual field of 24.0% which was significantly greater than after sham-stimulation (2.5%). This improvement persisted for at least 2 months in terms of both within- and between-group comparisons. Secondary analyses revealed improvements of near-threshold visual fields in the central 5° and increased thresholds in static perimetry after rtACS and improved reaction times, but visual acuity did not change compared to shams. Visual field improvement induced by rtACS was associated with EEG power-spectra and coherence alterations in visual cortical networks which are interpreted as signs of neuromodulation. Current flow simulation indicates current in the frontal cortex, eye, and optic nerve and in the subcortical but not in the cortical regions. Conclusion rtACS treatment is a safe and effective means to partially restore vision after optic nerve damage probably by modulating brain plasticity. This class 1 evidence suggests that visual fields can be improved in a clinically meaningful way. Trial Registration ClinicalTrials.gov NCT01280877 PMID:27355577

  17. Hybrid electro-optical stimulation of the rat sciatic nerve induces force generation in the plantarflexor muscles

    NASA Astrophysics Data System (ADS)

    Duke, Austin R.; Peterson, Erik; Mackanos, Mark A.; Atkinson, James; Tyler, Dustin; Jansen, E. Duco

    2012-12-01

    Objective. Optical methods of neural activation are becoming important tools for the study and treatment of neurological disorders. Infrared nerve stimulation (INS) is an optical technique exhibiting spatially precise activation in the native neural system. While this technique shows great promise, the risk of thermal damage may limit some applications. Combining INS with traditional electrical stimulation, a method known as hybrid electro-optical stimulation, reduces the laser power requirements and mitigates the risk of thermal damage while maintaining spatial selectivity. Here we investigate the capability of inducing force generation in the rat hind limb through hybrid stimulation of the sciatic nerve. Approach. Hybrid stimulation was achieved by combining an optically transparent nerve cuff for electrical stimulation and a diode laser coupled to an optical fiber for infrared stimulation. Force generation in the rat plantarflexor muscles was measured in response to hybrid stimulation with 1 s bursts of pulses at 15 and 20 Hz and with a burst frequency of 0.5 Hz. Main results. Forces were found to increase with successive stimulus trains, ultimately reaching a plateau by the 20th train. Hybrid evoked forces decayed at a rate similar to the rate of thermal diffusion in tissue. Preconditioning the nerve with an optical stimulus resulted in an increase in the force response to both electrical and hybrid stimulation. Histological evaluation showed no signs of thermally induced morphological changes following hybrid stimulation. Our results indicate that an increase in baseline temperature is a likely contributor to hybrid force generation. Significance. Extraneural INS of peripheral nerves at physiologically relevant repetition rates is possible using hybrid electro-optical stimulation.

  18. The combined effects of transcutaneous electrical nerve stimulation (TENS) and stretching on muscle hardness and pressure pain threshold

    PubMed Central

    Karasuno, Hiroshi; Ogihara, Hisayoshi; Morishita, Katsuyuki; Yokoi, Yuka; Fujiwara, Takayuki; Ogoma, Yoshiro; Abe, Koji

    2016-01-01

    [Purpose] This study aimed to clarify the immediate effects of a combined transcutaneous electrical nerve stimulation and stretching protocol. [Subjects] Fifteen healthy young males volunteered to participate in this study. The inclusion criterion was a straight leg raising range of motion of less than 70 degrees. [Methods] Subjects performed two protocols: 1) stretching (S group) of the medial hamstrings, and 2) tanscutaneous electrical nerve stimulation (100 Hz) with stretching (TS group). The TS group included a 20-minute electrical stimulation period followed by 10 minutes of stretching. The S group performed 10 minutes of stretching. Muscle hardness, pressure pain threshold, and straight leg raising range of motion were analyzed to evaluate the effects. The data were collected before transcutaneous electrical nerve stimulation (T1), before stretching (T2), immediately after stretching (T3), and 10 minutes after stretching (T4). [Results] Combined transcutaneous electrical nerve stimulation and stretching had significantly beneficial effects on muscle hardness, pressure pain threshold, and straight leg raising range of motion at T2, T3, and T4 compared with T1. [Conclusion] These results support the belief that transcutaneous electrical nerve stimulation combined with stretching is effective in reducing pain and decreasing muscle hardness, thus increasing range of motion. PMID:27190439

  19. The combined effects of transcutaneous electrical nerve stimulation (TENS) and stretching on muscle hardness and pressure pain threshold.

    PubMed

    Karasuno, Hiroshi; Ogihara, Hisayoshi; Morishita, Katsuyuki; Yokoi, Yuka; Fujiwara, Takayuki; Ogoma, Yoshiro; Abe, Koji

    2016-04-01

    [Purpose] This study aimed to clarify the immediate effects of a combined transcutaneous electrical nerve stimulation and stretching protocol. [Subjects] Fifteen healthy young males volunteered to participate in this study. The inclusion criterion was a straight leg raising range of motion of less than 70 degrees. [Methods] Subjects performed two protocols: 1) stretching (S group) of the medial hamstrings, and 2) tanscutaneous electrical nerve stimulation (100 Hz) with stretching (TS group). The TS group included a 20-minute electrical stimulation period followed by 10 minutes of stretching. The S group performed 10 minutes of stretching. Muscle hardness, pressure pain threshold, and straight leg raising range of motion were analyzed to evaluate the effects. The data were collected before transcutaneous electrical nerve stimulation (T1), before stretching (T2), immediately after stretching (T3), and 10 minutes after stretching (T4). [Results] Combined transcutaneous electrical nerve stimulation and stretching had significantly beneficial effects on muscle hardness, pressure pain threshold, and straight leg raising range of motion at T2, T3, and T4 compared with T1. [Conclusion] These results support the belief that transcutaneous electrical nerve stimulation combined with stretching is effective in reducing pain and decreasing muscle hardness, thus increasing range of motion. PMID:27190439

  20. The combined effects of transcutaneous electrical nerve stimulation (TENS) and stretching on muscle hardness and pressure pain threshold.

    PubMed

    Karasuno, Hiroshi; Ogihara, Hisayoshi; Morishita, Katsuyuki; Yokoi, Yuka; Fujiwara, Takayuki; Ogoma, Yoshiro; Abe, Koji

    2016-04-01

    [Purpose] This study aimed to clarify the immediate effects of a combined transcutaneous electrical nerve stimulation and stretching protocol. [Subjects] Fifteen healthy young males volunteered to participate in this study. The inclusion criterion was a straight leg raising range of motion of less than 70 degrees. [Methods] Subjects performed two protocols: 1) stretching (S group) of the medial hamstrings, and 2) tanscutaneous electrical nerve stimulation (100 Hz) with stretching (TS group). The TS group included a 20-minute electrical stimulation period followed by 10 minutes of stretching. The S group performed 10 minutes of stretching. Muscle hardness, pressure pain threshold, and straight leg raising range of motion were analyzed to evaluate the effects. The data were collected before transcutaneous electrical nerve stimulation (T1), before stretching (T2), immediately after stretching (T3), and 10 minutes after stretching (T4). [Results] Combined transcutaneous electrical nerve stimulation and stretching had significantly beneficial effects on muscle hardness, pressure pain threshold, and straight leg raising range of motion at T2, T3, and T4 compared with T1. [Conclusion] These results support the belief that transcutaneous electrical nerve stimulation combined with stretching is effective in reducing pain and decreasing muscle hardness, thus increasing range of motion.

  1. Refining the Sensory and Motor Ratunculus of the Rat Upper Extremity Using fMRI and Direct Nerve Stimulation

    PubMed Central

    Cho, Younghoon R.; Pawela, Christopher P.; Li, Rupeng; Kao, Dennis; Schulte, Marie L.; Runquist, Matthew L.; Yan, Ji-Geng; Matloub, Hani S.; Jaradeh, Safwan S.; Hudetz, Anthony G.; Hyde, James S.

    2008-01-01

    It is well understood that the different regions of the body have cortical representations in proportion to the degree of innervation. Our current understanding of the rat upper extremity has been enhanced using functional MRI (fMRI), but these studies are often limited to the rat forepaw. The purpose of this study is to describe a new technique that allows us to refine the sensory and motor representations in the cerebral cortex by surgically implanting electrodes on the major nerves of the rat upper extremity and providing direct electrical nerve stimulation while acquiring fMRI images. This technique was used to stimulate the ulnar, median, radial, and musculocutaneous nerves in the rat upper extremity using four different stimulation sequences that varied in frequency (5 Hz vs. 10 Hz) and current (0.5 mA vs. 1.0 mA). A distinct pattern of cortical activation was found for each nerve. The higher stimulation current resulted in a dramatic increase in the level of cortical activation. The higher stimulation frequency resulted in both increases and attenuation of cortical activation in different regions of the brain, depending on which nerve was stimulated. PMID:17969116

  2. Frequency-dependent effects of sine-wave cranial transcutaneous electrical nerve stimulation in human subjects.

    PubMed

    Taylor, D N; Lee, C T

    1992-01-01

    In a double-blind protocol, ninety healthy volunteer subjects received 30 minutes of constant current sine-wave cranial transcutaneous electrical nerve stimulation (TENS) of 5 Hertz (Hz), 100 Hz, or 2000 Hz frequency (current maintained below .5 mA for safety), placebo TENS, or no treatment. The five groups were compared on pre- to posttreatment changes in blood pressure, heart rate, peripheral temperature, and anxiety. Analysis showed significant reductions in systolic and diastolic blood pressure and heart rate after 100 Hz cranial TENS as compared to the other groups. No other differences achieved significance. PMID:1357927

  3. Epidermal laser stimulation of action potentials in the frog sciatic nerve

    NASA Astrophysics Data System (ADS)

    Jindra, Nichole M.; Goddard, Douglas; Imholte, Michelle; Thomas, Robert J.

    2010-01-01

    Measurements of laser-stimulated action potentials in the sciatic nerve of leopard frogs (Rana pipiens) are made using two infrared lasers. The dorsal sides of the frog's hind limbs are exposed to short-pulsed 1540- and 1064-nm wavelengths at three separate spot sizes: 2, 3, and 4 mm. Energy density thresholds are determined for eliciting an action potential at each experimental condition. Results from these exposures show similar evoked potential thresholds for both wavelengths. The 2-mm-diam spot sizes yield action potentials at radiant exposure levels almost double that seen with larger beam sizes.

  4. A comparison of pulmonary function tests for postthoracotomy pain using cryoanalgesia and transcutaneous nerve stimulation.

    PubMed

    Rooney, S M; Jain, S; McCormack, P; Bains, M S; Martini, N; Goldiner, P L

    1986-02-01

    The beneficial effects of transcutaneous nerve stimulation (TNS) and cryoanalgesia for post-thoracotomy pain were compared against each other and against a control group through pulmonary function testing in the immediate and delayed postoperative period. Patients receiving cryoanalgesia did not perform well in the first 24 hours after operation. However, by the fifth postoperative day, they did as well as or even better than the TNS patients. Both cryoanalgesia and TNS were significantly effective in the management of postoperative pain as compared with controls. PMID:3484939

  5. Neuralgia associated with transcutaneous electrical nerve stimulation therapy in a patient initially diagnosed with temporomandibular disorder.

    PubMed

    Omolehinwa, Temitope T; Musbah, Thamer; Desai, Bhavik; O'Malley, Bert W; Stoopler, Eric T

    2015-03-01

    Head and neck neoplasms may be difficult to detect because of wide-ranging symptoms and the presence of overlapping anatomic structures in the region. This case report describes a patient with chronic otalgia and temporomandibular disorder, who developed sudden-onset neuralgia while receiving transcutaneous electrical nerve stimulation (TENS) therapy. Further diagnostic evaluation revealed a skull base tumor consistent with adenoid cystic carcinoma. To our knowledge, this is the first report of TENS-associated neuralgia leading to a diagnosis of primary intracranial adenoid cystic carcinoma.

  6. Low-frequency sinusoidal galvanic stimulation of the left and right vestibular nerves reveals two peaks of modulation in muscle sympathetic nerve activity.

    PubMed

    Hammam, Elie; James, Cheree; Dawood, Tye; Macefield, Vaughan G

    2011-09-01

    Studies previously performed in our laboratory have shown that sinusoidal galvanic vestibular stimulation (sGVS), a means of selectively modulating vestibular input without affecting other inputs, can cause partial entrainment of muscle sympathetic nerve activity (MSNA) at frequencies ranging from 0.2 to 2.0 Hz. Here we test the effect of sGVS on sympathetic outflow when stimulating the vestibular system at lower frequencies. MSNA was recorded via tungsten microelectrodes inserted into the left common peroneal nerve in 12 awake, seated subjects. Bipolar binaural sinusoidal GVS (±2 mA, 100 cycles) was applied to the mastoid processes at 0.08, 0.13 and 0.18 Hz. Cross-correlation analysis revealed two bursts of modulation of MSNA for each cycle of stimulation. We believe the primary peak is related to the positive phase of the sinusoid, in which the right vestibular nerve is hyperpolarised and the left vestibular nerve depolarised. Furthermore, we believe the secondary peak is related to the negative phase of the sinusoid (depolarisation of the right vestibular nerve and hyperpolarisation of the left vestibular nerve). This was never observed at higher frequencies of stimulation, presumably because at such frequencies there is insufficient time for a second peak to be expressed. The incidence of double peaks of MSNA was highest at 0.08 Hz and lowest at 0.18 Hz. These observations emphasise the role of the vestibular apparatus in the control of blood pressure, and further suggest convergence of bilateral inputs from vestibular nuclei onto the output nuclei from which MSNA originates, the rostral ventrolateral medulla (RVLM).

  7. Comparing the magnetic resonant coupling radiofrequency stimulation to the traditional approaches: Ex-vivo tissue voltage measurement and electromagnetic simulation analysis

    SciTech Connect

    Yeung, Sai Ho; Pradhan, Raunaq; Feng, Xiaohua; Zheng, Yuanjin

    2015-09-15

    Recently, the design concept of magnetic resonant coupling has been adapted to electromagnetic therapy applications such as non-invasive radiofrequency (RF) stimulation. This technique can significantly increase the electric field radiated from the magnetic coil at the stimulation target, and hence enhancing the current flowing through the nerve, thus enabling stimulation. In this paper, the developed magnetic resonant coupling (MRC) stimulation, magnetic stimulation (MS) and transcutaneous electrical nerve stimulation (TENS) are compared. The differences between the MRC RF stimulation and other techniques are presented in terms of the operating mechanism, ex-vivo tissue voltage measurement and electromagnetic simulation analysis. The ev-vivo tissue voltage measurement experiment is performed on the compared devices based on measuring the voltage induced by electromagnetic induction at the tissue. The focusing effect, E field and voltage induced across the tissue, and the attenuation due to the increase of separation between the coil and the target are analyzed. The electromagnetic stimulation will also be performed to obtain the electric field and magnetic field distribution around the biological medium. The electric field intensity is proportional to the induced current and the magnetic field is corresponding to the electromagnetic induction across the biological medium. The comparison between the MRC RF stimulator and the MS and TENS devices revealed that the MRC RF stimulator has several advantages over the others for the applications of inducing current in the biological medium for stimulation purposes.

  8. Comparing the magnetic resonant coupling radiofrequency stimulation to the traditional approaches: Ex-vivo tissue voltage measurement and electromagnetic simulation analysis

    NASA Astrophysics Data System (ADS)

    Yeung, Sai Ho; Pradhan, Raunaq; Feng, Xiaohua; Zheng, Yuanjin

    2015-09-01

    Recently, the design concept of magnetic resonant coupling has been adapted to electromagnetic therapy applications such as non-invasive radiofrequency (RF) stimulation. This technique can significantly increase the electric field radiated from the magnetic coil at the stimulation target, and hence enhancing the current flowing through the nerve, thus enabling stimulation. In this paper, the developed magnetic resonant coupling (MRC) stimulation, magnetic stimulation (MS) and transcutaneous electrical nerve stimulation (TENS) are compared. The differences between the MRC RF stimulation and other techniques are presented in terms of the operating mechanism, ex-vivo tissue voltage measurement and electromagnetic simulation analysis. The ev-vivo tissue voltage measurement experiment is performed on the compared devices based on measuring the voltage induced by electromagnetic induction at the tissue. The focusing effect, E field and voltage induced across the tissue, and the attenuation due to the increase of separation between the coil and the target are analyzed. The electromagnetic stimulation will also be performed to obtain the electric field and magnetic field distribution around the biological medium. The electric field intensity is proportional to the induced current and the magnetic field is corresponding to the electromagnetic induction across the biological medium. The comparison between the MRC RF stimulator and the MS and TENS devices revealed that the MRC RF stimulator has several advantages over the others for the applications of inducing current in the biological medium for stimulation purposes.

  9. Effect of Transcranial Magnetic Stimulation on Neuronal Networks

    NASA Astrophysics Data System (ADS)

    Unsal, Ahmet; Hadimani, Ravi; Jiles, David

    2013-03-01

    The human brain contains around 100 billion nerve cells controlling our day to day activities. Consequently, brain disorders often result in impairments such as paralysis, loss of coordination and seizure. It has been said that 1 in 5 Americans suffer some diagnosable mental disorder. There is an urgent need to understand the disorders, prevent them and if possible, develop permanent cure for them. As a result, a significant amount of research activities is being directed towards brain research. Transcranial Magnetic Stimulation (TMS) is a promising tool for diagnosing and treating brain disorders. It is a non-invasive treatment method that produces a current flow in the brain which excites the neurons. Even though TMS has been verified to have advantageous effects on various brain related disorders, there have not been enough studies on the impact of TMS on cells. In this study, we are investigating the electrophysiological effects of TMS on one dimensional neuronal culture grown in a circular pathway. Electrical currents are produced on the neuronal networks depending on the directionality of the applied field. This aids in understanding how neuronal networks react under TMS treatment.

  10. A system for delivering mechanical stimulation and robot-assisted therapy to the rat whisker pad during facial nerve regeneration.

    PubMed

    Heaton, James T; Knox, Christopher J; Malo, Juan S; Kobler, James B; Hadlock, Tessa A

    2013-11-01

    Functional recovery is typically poor after facial nerve transection and surgical repair. In rats, whisking amplitude remains greatly diminished after facial nerve regeneration, but can recover more completely if the whiskers are periodically mechanically stimulated during recovery. Here we present a robotic "whisk assist" system for mechanically driving whisker movement after facial nerve injury. Movement patterns were either preprogrammed to reflect natural amplitudes and frequencies, or movements of the contralateral (healthy) side of the face were detected and used to control real-time mirror-like motion on the denervated side. In a pilot study, 20 rats were divided into nine groups and administered one of eight different whisk assist driving patterns (or control) for 5-20 minutes, five days per week, across eight weeks of recovery after unilateral facial nerve cut and suture repair. All rats tolerated the mechanical stimulation well. Seven of the eight treatment groups recovered average whisking amplitudes that exceeded controls, although small group sizes precluded statistical confirmation of group differences. The potential to substantially improve facial nerve recovery through mechanical stimulation has important clinical implications, and we have developed a system to control the pattern and dose of stimulation in the rat facial nerve model.

  11. How does vagal nerve stimulation (VNS) change EEG brain functional connectivity?

    PubMed

    Bartolomei, Fabrice; Bonini, Francesca; Vidal, Elsa; Trébuchon, Agnes; Lagarde, Stanislas; Lambert, Isabelle; McGonigal, Aileen; Scavarda, Didier; Carron, Romain; Benar, Christian G

    2016-10-01

    An effect of vagal nerve stimulation (VNS) on cortical synchronization has been postulated but remains to be verified. In this study we investigated the impact of VNS on functional connectivity (Fc) using direct intracerebral recordings (stereotactic EEG, SEEG). Five patients with epilepsy who underwent SEEG recordings during ongoing VNS therapy were investigated. Interdependencies between twenty-six selected bipolar SEEG channels were estimated by nonlinear regression analysis during ON and OF periods of stimulation. In comparison with OFF periods, the ON periods disclosed higher values for four patients (P1, P3, P4, P5) and lower values for one patient (P2). From thresholded graphs, we observed increased connections between several brain regions in P1 and P5 and decreased connections in P2. Finally, the only decreased Fc occurring during VNS corresponded to the responder patient, suggesting that therapeutic impact might be related to this mechanism. PMID:27497814

  12. Transcranial magnetic stimulation: Improved coil design for deep brain investigation

    NASA Astrophysics Data System (ADS)

    Crowther, L. J.; Marketos, P.; Williams, P. I.; Melikhov, Y.; Jiles, D. C.; Starzewski, J. H.

    2011-04-01

    This paper reports on a design for a coil for transcranial magnetic stimulation. The design shows potential for improving the penetration depth of the magnetic field, allowing stimulation of subcortical structures within the brain. The magnetic and induced electric fields in the human head have been calculated with finite element electromagnetic modeling software and compared with empirical measurements. Results show that the coil design used gives improved penetration depth, but also indicates the likelihood of stimulation of additional tissue resulting from the spatial distribution of the magnetic field.

  13. Clinical applications of diffusion magnetic resonance imaging of the lumbar foraminal nerve root entrapment

    PubMed Central

    Ohtori, Seiji; Yamashita, Masaomi; Yamauchi, Kazuyo; Suzuki, Munetaka; Orita, Sumihisa; Kamoda, Hiroto; Arai, Gen; Ishikawa, Tetsuhiro; Miyagi, Masayuki; Ochiai, Nobuyasu; Kishida, Shunji; Masuda, Yoshitada; Ochi, Shigehiro; Kikawa, Takashi; Takaso, Masashi; Aoki, Yasuchika; Toyone, Tomoaki; Suzuki, Takane; Takahashi, Kazuhisa

    2010-01-01

    Diffusion-weighted imaging (DWI) can provide valuable structural information about tissues that may be useful for clinical applications in evaluating lumbar foraminal nerve root entrapment. Our purpose was to visualize the lumbar nerve root and to analyze its morphology, and to measure its apparent diffusion coefficient (ADC) in healthy volunteers and patients with lumbar foraminal stenosis using 1.5-T magnetic resonance imaging. Fourteen patients with lumbar foraminal stenosis and 14 healthy volunteers were studied. Regions of interest were placed at the fourth and fifth lumbar root at dorsal root ganglia and distal spinal nerves (at L4 and L5) and the first sacral root and distal spinal nerve (S1) on DWI to quantify mean ADC values. The anatomic parameters of the spinal nerve roots can also be determined by neurography. In patients, mean ADC values were significantly higher in entrapped roots and distal spinal nerve than in intact ones. Neurography also showed abnormalities such as nerve indentation, swelling and running transversely in their course through the foramen. In all patients, leg pain was ameliorated after selective decompression (n = 9) or nerve block (n = 5). We demonstrated the first use of DWI and neurography of human lumbar nerves to visualize and quantitatively evaluate lumbar nerve entrapment with foraminal stenosis. We believe that DWI is a potential tool for diagnosis of lumbar nerve entrapment. PMID:20632042

  14. Membrane depolarization and carbamoylcholine stimulate phosphatidylinositol turnover in intact nerve terminals

    SciTech Connect

    Audigier, S.M.P.; Wang, J.K.T.; Greengard, P.

    1988-04-01

    Synaptosomes, purified from rat cerebral cortex, were prelabeled with (/sup 3/H)inositol to study phosphatidylinositol turnover in nerve terminals. Labeled synaptosomes were either depolarized with 40 mM K/sup +/ or exposed to carbamoylcholine (carbachol). K/sup +/ depolarization increased the level of inositol phosphates in a time-dependent manner. The inositol bisphosphate level also increased rapidly, but its elevated level was sustained during continued depolarization. The elevated level of inositol bisphosphate was reversed upon repolarization of the synaptosomes. The level of inositol monophosphate increased slowly to 120-130% of control. These effects of K/sup +/ depolarization depended on the presence of Ca/sup 2 +/ in the incubation medium. Carbachol stimulated the turnover of phosphatidylinositol in a dose- and time-dependent manner. The level of inositol bisphosphate increased to 210% of control, and this maximal response was seen from 15 to 60 min. Accumulation of inositol monophosphate was larger than that of inositol bisphosphate, but its time course was slower. Atropine and pirenzepine inhibited the carbachol effect with high affinities. These data show that both Ca/sup 2 +/ influx and M/sub 1/ muscarinic receptor activation stimulate phospholipase C activity in synaptosomes, suggesting that phosphatidylinositol turnover may be involved in regulating neurotransmitter release from nerve terminals.

  15. Selective bilateral activation of leg muscles after cutaneous nerve stimulation during backward walking

    PubMed Central

    Massaad, Firas; Jansen, Karen; Bruijn, Sjoerd M.; Duysens, Jacques

    2012-01-01

    During human locomotion, cutaneous reflexes have been suggested to function to preserve balance. Specifically, cutaneous reflexes in the contralateral leg's muscles (with respect to the stimulus) were suggested to play an important role in maintaining stability during locomotor tasks where stability is threatened. We used backward walking (BW) as a paradigm to induce unstable gait and analyzed the cutaneous reflex activity in both ipsilateral and contralateral lower limb muscles after stimulation of the sural nerve at different phases of the gait cycle. In BW, the tibialis anterior (TA) reflex activity in the contralateral leg was markedly higher than TA background EMG activity during its stance phase. In addition, in BW a substantial reflex suppression was observed in the ipsilateral biceps femoris during the stance-swing transition in some participants, while for medial gastrocnemius the reflex activity was equal to background activity in both legs. To test whether the pronounced crossed responses in TA could be related to instability, the responses were correlated with measures of stability (short-term maximum Lyapunov exponents and step width). These measures were higher for BW compared with forward walking, indicating that BW is less stable. However, there was no significant correlation between these measures and the amplitude of the crossed TA responses in BW. It is therefore proposed that these crossed responses are related to an attempt to briefly slow down (TA decelerates the center of mass in the single-stance period) in the light of unexpected perturbations, such as provided by the sural nerve stimulation. PMID:22773779

  16. Role of transcutaneous electric nerve stimulation in the management of trigeminal neuralgia

    PubMed Central

    Singla, Sanju; Prabhakar, Vikram; Singla, Rajan Kumar

    2011-01-01

    Background: Trigeminal neuralgia typically involves nerves supplying teeth, jaws and face of older females. Though the etiology is usually obscure, different treatment modalities have been tried for it viz. medicinal treatment, injection alcohol, peripheral neurectomy, rhizotomy, and microvascular decompression etc. Transcutaneous electric nerve stimulation (TENS) is an emerging and promising option for management of such patients. Aims and Design: The present study was designed with an aim to study the efficacy of TENS in management of trigeminal neuralgia. Materials and Methods: The study was conducted on 30 patients of trigeminal neuralgia confirmed by diagnostic nerve block. They were given bursts of TENS for 20-40 days over the path of the affected nerve and subsequently evaluated at 1 month and 3 month intervals by visual analogue scale (VAS), verbal pain scale (VPS), a functional outcome scales for main daily activities like sleep, chewing, talking, or washing face. Results: The results showed that, on VAS, the score decreased from 8.9 (Pre TENS) to 3.1 at 1 month and 1.3 at 3 months, and on VPS, the score decreased from 3.5 (Pre TENS) to 1.2 at 1 month and 0.3 at 3 months. Similarly, a considerable decrease in scores was seen on functional outcome scale for different activities. No side effects like irritation or redness of skin were seen in any of the patients. Conclusions: Thus, TENS was found to be a safe, easily acceptable, and non-invasive outdoor patient department procedure for management of trigeminal neuralgia. PMID:21897677

  17. Transcranial Magnetic Stimulation for Status Epilepticus

    PubMed Central

    Zeiler, F. A.; Matuszczak, M.; Teitelbaum, J.; Gillman, L. M.; Kazina, C. J.

    2015-01-01

    Background. Our goal was to perform a systematic review on the use of repetitive transcranial magnetic stimulation (rTMS) in the treatment of status epilepticus (SE) and refractory status epilepticus (RSE). Methods. MEDLINE, BIOSIS, EMBASE, Global Health, Healthstar, Scopus, Cochrane Library, the International Clinical Trials Registry Platform, clinicaltrials.gov (inception to August 2015), and gray literature were searched. The strength of evidence was adjudicated using Oxford and GRADE methodology. Results. We identified 11 original articles. Twenty-one patients were described, with 13 adult and 8 pediatric. All studies were retrospective. Seizure reduction/control with rTMS occurred in 15 of the 21 patients (71.4%), with 5 (23.8%) and 10 (47.6%) displaying partial and complete responses, respectively. Seizures recurred after rTMS in 73.3% of the patients who had initially responded. All studies were an Oxford level 4, GRADE D level of evidence. Conclusions. Oxford level 4, GRADE D evidence exists to suggest a potential impact on seizure control with the use of rTMS for FSE and FRSE, though durability of the therapy is short-lived. Routine use of rTMS in this context cannot be recommended at this time. Further prospective study of this intervention is warranted. PMID:26682065

  18. Transcranial magnetic stimulation (TMS) inhibits cortical dendrites

    PubMed Central

    Murphy, Sean C; Palmer, Lucy M; Nyffeler, Thomas; Müri, René M; Larkum, Matthew E

    2016-01-01

    One of the leading approaches to non-invasively treat a variety of brain disorders is transcranial magnetic stimulation (TMS). However, despite its clinical prevalence, very little is known about the action of TMS at the cellular level let alone what effect it might have at the subcellular level (e.g. dendrites). Here, we examine the effect of single-pulse TMS on dendritic activity in layer 5 pyramidal neurons of the somatosensory cortex using an optical fiber imaging approach. We find that TMS causes GABAB-mediated inhibition of sensory-evoked dendritic Ca2+ activity. We conclude that TMS directly activates fibers within the upper cortical layers that leads to the activation of dendrite-targeting inhibitory neurons which in turn suppress dendritic Ca2+ activity. This result implies a specificity of TMS at the dendritic level that could in principle be exploited for investigating these structures non-invasively. DOI: http://dx.doi.org/10.7554/eLife.13598.001 PMID:26988796

  19. Electrochemical properties of titanium nitride nerve stimulation electrodes: an in vitro and in vivo study.

    PubMed

    Meijs, Suzan; Fjorback, Morten; Jensen, Carina; Sørensen, Søren; Rechendorff, Kristian; Rijkhoff, Nico J M

    2015-01-01

    The in vivo electrochemical behavior of titanium nitride (TiN) nerve stimulation electrodes was compared to their in vitro behavior for a period of 90 days. Ten electrodes were implanted in two Göttingen minipigs. Four of these were used for electrical stimulation and electrochemical measurements. Five electrodes were kept in Ringer's solution at 37.5°C, of which four were used for electrical stimulation and electrochemical measurements. The voltage transients measured in vivo were 13 times greater than in vitro at implantation and they continued to increase with time. The electrochemical properties in vivo and the tissue resistance (Rtissue) followed a similar trend with time. There was no consistent significant difference between the electrochemical properties of the in vivo and in vitro electrodes after the implanted period. The differences between the in vivo and in vitro electrodes during the implanted period show that the evaluation of electrochemical performance of implantable stimulation electrodes cannot be substituted with in vitro measurements. After the implanted period, however, the performance of the in vivo and in vitro electrodes in saline was similar. In addition, the changes observed over time during the post-implantation period regarding the electrochemical properties of the in vivo electrodes and Rtissue were similar, which indicates that these changes are due to the foreign body response to implantation.

  20. Electrochemical properties of titanium nitride nerve stimulation electrodes: an in vitro and in vivo study

    PubMed Central

    Meijs, Suzan; Fjorback, Morten; Jensen, Carina; Sørensen, Søren; Rechendorff, Kristian; Rijkhoff, Nico J. M.

    2015-01-01

    The in vivo electrochemical behavior of titanium nitride (TiN) nerve stimulation electrodes was compared to their in vitro behavior for a period of 90 days. Ten electrodes were implanted in two Göttingen minipigs. Four of these were used for electrical stimulation and electrochemical measurements. Five electrodes were kept in Ringer's solution at 37.5°C, of which four were used for electrical stimulation and electrochemical measurements. The voltage transients measured in vivo were 13 times greater than in vitro at implantation and they continued to increase with time. The electrochemical properties in vivo and the tissue resistance (Rtissue) followed a similar trend with time. There was no consistent significant difference between the electrochemical properties of the in vivo and in vitro electrodes after the implanted period. The differences between the in vivo and in vitro electrodes during the implanted period show that the evaluation of electrochemical performance of implantable stimulation electrodes cannot be substituted with in vitro measurements. After the implanted period, however, the performance of the in vivo and in vitro electrodes in saline was similar. In addition, the changes observed over time during the post-implantation period regarding the electrochemical properties of the in vivo electrodes and Rtissue were similar, which indicates that these changes are due to the foreign body response to implantation. PMID:26300717

  1. Transmembrane potential induced in a spherical cell model under low-frequency magnetic stimulation

    NASA Astrophysics Data System (ADS)

    Ye, Hui; Cotic, Marija; Carlen, Peter L.

    2007-09-01

    Time-varying magnetic fields can induce electric fields in the neuronal tissue, a phenomenon that has been recently explored in clinical applications such as peripheral nerve stimulation and transcranial magnetic stimulation. Although the transmembrane potential induced during direct electric stimulation has already been the subject of a number of theoretical studies, an analytical solution for the magnetically induced transmembrane potential change is still unavailable. In addition, although several studies have analyzed the impact of stimulation parameters, including stimulation intensity and frequency, as well as coil design and position, on the amount of tissue polarization, the effects of tissue non-homogeneity on cell polarization have not been fully elucidated. In this study, we have derived an analytical expression for the transmembrane potential induced by a low-frequency magnetic field in a spherical neuronal structure. This model is representative of a spherical cell body or any neuronal structure of a similar shape. The model cell is located in an extracellular medium and possesses a low-conductive membrane and an internal cytoplasm. These three regions represent the basic tissue non-homogeneity of a neuron at a microscopic level. The sensitivity of the induced transmembrane potential to the coil position and to the geometrical and electrical parameters of the model structure was studied in a broad physiologically relevant range. Our results demonstrate that the structure is regionally polarized, with the pattern of polarization depending on the relative positioning between the model cell and the stimulation coil. In addition, both the geometrical and electrical parameters of the structure affect the amount of polarization. These results may be generalized to other neuronal tissues that possess similar non-homogenous properties, but different shapes, such as an axon. Our results support the idea that aside from coil design and position, tissue non

  2. Ultrasound-guided Continuous Axillary Brachial Plexus Block Using a Nerve Stimulating Catheter: EpiStim® Catheter

    PubMed Central

    Lee, Mi Kyoung; Kim, Jung Eun; Kim, Se Hee; Yeo, Gwi Eun

    2015-01-01

    Brachial plexus block (BPB) under ultrasound guidance has come to be widely used. However, nerve injury has been reported following ultrasound-guided BPB. We hypothesized that BPB under ultrasound guidance in conjunction with real-time electrical nerve stimulation would help us prevent nerve injury and do more successful procedure. Here, we report the successful induction and maintenance of ultrasound-guided BPB and the achievement of good peri- and postoperative pain control using a conductive catheter, the EpiStim®. PMID:26495085

  3. Automatic Vagus Nerve Stimulation Triggered by Ictal Tachycardia: Clinical Outcomes and Device Performance—The U.S. E‐37 Trial

    PubMed Central

    Afra, Pegah; Macken, Micheal; Minecan, Daniela N.; Bagić, Anto; Benbadis, Selim R.; Helmers, Sandra L.; Sinha, Saurabh R.; Slater, Jeremy; Treiman, David; Begnaud, Jason; Raman, Pradheep; Najimipour, Bita

    2015-01-01

    Objectives The Automatic Stimulation Mode (AutoStim) feature of the Model 106 Vagus Nerve Stimulation (VNS) Therapy System stimulates the left vagus nerve on detecting tachycardia. This study evaluates performance, safety of the AutoStim feature during a 3‐5‐day Epilepsy Monitoring Unit (EMU) stay and long‐ term clinical outcomes of the device stimulating in all modes. Materials and Methods The E‐37 protocol (NCT01846741) was a prospective, unblinded, U.S. multisite study of the AspireSR® in subjects with drug‐resistant partial onset seizures and history of ictal tachycardia. VNS Normal and Magnet Modes stimulation were present at all times except during the EMU stay. Outpatient visits at 3, 6, and 12 months tracked seizure frequency, severity, quality of life, and adverse events. Results Twenty implanted subjects (ages 21–69) experienced 89 seizures in the EMU. 28/38 (73.7%) of complex partial and secondarily generalized seizures exhibited ≥20% increase in heart rate change. 31/89 (34.8%) of seizures were treated by Automatic Stimulation on detection; 19/31 (61.3%) seizures ended during the stimulation with a median time from stimulation onset to seizure end of 35 sec. Mean duty cycle at six‐months increased from 11% to 16%. At 12 months, quality of life and seizure severity scores improved, and responder rate was 50%. Common adverse events were dysphonia (n = 7), convulsion (n = 6), and oropharyngeal pain (n = 3). Conclusions The Model 106 performed as intended in the study population, was well tolerated and associated with clinical improvement from baseline. The study design did not allow determination of which factors were responsible for improvements. PMID:26663671

  4. Impaired vascular responses to parasympathetic nerve stimulation and muscarinic receptor activation in the submandibular gland in nonobese diabetic mice

    PubMed Central

    Berggreen, Ellen; Nyløkken, Krister; Delaleu, Nicolas; Hajdaragic-Ibricevic, Hamijeta; Jonsson, Malin V

    2009-01-01

    Introduction Decreased vascular responses to salivary gland stimulation are observed in Sjögren's syndrome patients. We investigate whether impaired vascular responses to parasympathetic stimulation and muscarinic receptor activation in salivary glands parallels hyposalivation in an experimental model for Sjögren's syndrome. Methods Blood flow responses in the salivary glands were measured by laser Doppler flowmeter. Muscarinic receptor activation was followed by saliva secretion measurements. Nitric oxide synthesis-mediated blood flow responses were studied after administration of a nitric oxide synthase inhibitor. Glandular autonomic nerves and muscarinic 3 receptor distributions were also investigated. Results Maximal blood flow responses to parasympathetic stimulation and muscarinic receptor activation were significantly lower in nonobese diabetic (NOD) mice compared with BALB/c mice, coinciding with impaired saliva secretion in nonobese diabetic mice (P < 0.005). Nitric oxide synthase inhibitor had less effect on blood flow responses after parasympathetic nerve stimulation in nonobese diabetic mice compared with BALB/c mice (P < 0.02). In nonobese diabetic mice, salivary gland parasympathetic nerve fibres were absent in areas of focal infiltrates. Muscarinic 3 receptor might be localized in the blood vessel walls of salivary glands. Conclusions Impaired vasodilatation in response to parasympathetic nerve stimulation and muscarinic receptor activation may contribute to hyposalivation observed in nonobese diabetic mice. Reduced nitric oxide signalling after parasympathetic nerve stimulation may contribute in part to the impaired blood flow responses. The possibility of muscarinic 3 receptor in the vasculature supports the notion that muscarinic 3 receptor autoantibodies present in nonobese diabetic mice might impair the fluid transport required for salivation. Parasympathetic nerves were absent in areas of focal infiltrates, whereas a normal distribution was

  5. [Exploration Research of Treatment Effect Improvement of Transcutaneous Electrical Nerve Stimulation Using Parameter-changing Chaotic Signal].

    PubMed

    Zheng, Jincun; Zhang, Hui; Qin, Binyi; Wang, Hai; Nie, Guochao; Chen, Tiejun

    2015-10-01

    This article presents a transcutaneous electric stimulator that is based on chaotic signal. Firstly, we in the study used the MATLAB platform in the PC to generate chaotic signal through the chaos equation, and then we transferred the signal out by data acquisition equipment of USB-6251 manufactured by NI Company. In order to obtain high-power signal for transcutaneous electric stimulator, we used the chip of LM3886 to amplify the signal. Finally, we used the power-amplified chaotic signal to stimulate the internal nerve of human through the electrodes fixed on the skin. We obtained different stimulation effects of transcutaneous electric stimulator by changing the parameters of chaotic model. The preliminary test showed that the randomness of chaotic signals improved the applicability of electrical stimulation and the rules of chaos ensured that the stimulation was comfort. The method reported in this paper provides a new way for the design of transcutaneous electric stimulator.

  6. Electrical stimulation of the auditory nerve. I. Correlation of physiological responses with cochlear status.

    PubMed

    Shepherd, R K; Javel, E

    1997-06-01

    The purpose of the present study was to evaluate evoked potential and single fibre responses to biphasic current pulses in animals with varying degrees of cochlear pathology, and to correlate any differences in the physiological response with status of the auditory nerve. Six cats, whose cochleae ranged from normal to a severe neural loss (< 5% spiral ganglion survival), were used. Morphology of the electrically evoked auditory brainstem response (EABR) was similar across all animals, although electrophonic responses were only observed from the normal animal. In animals with extensive neural pathology, EABR thresholds were elevated and response amplitudes throughout the dynamic range were moderately reduced. Analysis of single VIIIth nerve fibre responses were based on 207 neurons. Spontaneous discharge rates among fibres depended on hearing status, with the majority of fibres recorded from deafened animals exhibiting little or no spontaneous activity. Electrical stimulation produced a monotonic increase in discharge rate, and a systematic reduction in response latency and temporal jitter as a function of stimulus intensity for all fibres examined. Short-duration current pulses elicited a highly synchronous response (latency < 0.7 ms), with a less well synchronized response sometimes present (0.7-1.1 ms). There were, however, a number of significant differences between responses from normal and deafened cochleae. Electrophonic activity was only present in recordings from the normal animal, while mean threshold, dynamic range and latency of the direct electrical response varied with cochlear pathology. Differences in the ability of fibres to follow high stimulation rates were also observed; while neurons from the normal cochlea were capable of 100% entrainment at high rates (600-800 pulses per second (pps)), fibres recorded from deafened animals were often not capable of such entrainment at rates above 400 pps. Finally, a number of fibres in deafened animals showed

  7. A Phenomenological Model of the Electrically Stimulated Auditory Nerve Fiber: Temporal and Biphasic Response Properties.

    PubMed

    Horne, Colin D F; Sumner, Christian J; Seeber, Bernhard U

    2016-01-01

    We present a phenomenological model of electrically stimulated auditory nerve fibers (ANFs). The model reproduces the probabilistic and temporal properties of the ANF response to both monophasic and biphasic stimuli, in isolation. The main contribution of the model lies in its ability to reproduce statistics of the ANF response (mean latency, jitter, and firing probability) under both monophasic and cathodic-anodic biphasic stimulation, without changing the model's parameters. The response statistics of the model depend on stimulus level and duration of the stimulating pulse, reproducing trends observed in the ANF. In the case of biphasic stimulation, the model reproduces the effects of pseudomonophasic pulse shapes and also the dependence on the interphase gap (IPG) of the stimulus pulse, an effect that is quantitatively reproduced. The model is fitted to ANF data using a procedure that uniquely determines each model parameter. It is thus possible to rapidly parameterize a large population of neurons to reproduce a given set of response statistic distributions. Our work extends the stochastic leaky integrate and fire (SLIF) neuron, a well-studied phenomenological model of the electrically stimulated neuron. We extend the SLIF neuron so as to produce a realistic latency distribution by delaying the moment of spiking. During this delay, spiking may be abolished by anodic current. By this means, the probability of the model neuron responding to a stimulus is reduced when a trailing phase of opposite polarity is introduced. By introducing a minimum wait period that must elapse before a spike may be emitted, the model is able to reproduce the differences in the threshold level observed in the ANF for monophasic and biphasic stimuli. Thus, the ANF response to a large variety of pulse shapes are reproduced correctly by this model.

  8. Central modulation in cluster headache patients treated with occipital nerve stimulation: an FDG-PET study

    PubMed Central

    2011-01-01

    Background Occipital nerve stimulation (ONS) has raised new hope for drug-resistant chronic cluster headache (drCCH), a devastating condition. However its mode of action remains elusive. Since the long delay to meaningful effect suggests that ONS induces slow neuromodulation, we have searched for changes in central pain-control areas using metabolic neuroimaging. Methods Ten drCCH patients underwent an 18FDG-PET scan after ONS, at delays varying between 0 and 30 months. All were scanned with ongoing ONS (ON) and with the stimulator switched OFF. Results After 6-30 months of ONS, 3 patients were pain free and 4 had a ≥ 90% reduction of attack frequency (responders). In all patients compared to controls, several areas of the pain matrix showed hypermetabolism: ipsilateral hypothalamus, midbrain and ipsilateral lower pons. All normalized after ONS, except for the hypothalamus. Switching the stimulator ON or OFF had little influence on brain glucose metabolism. The perigenual anterior cingulate cortex (PACC) was hyperactive in ONS responders compared to non-responders. Conclusions Metabolic normalization in the pain neuromatrix and lack of short-term changes induced by the stimulation might support the hypothesis that ONS acts in drCCH through slow neuromodulatory processes. Selective activation in responders of PACC, a pivotal structure in the endogenous opioid system, suggests that ONS could restore balance within dysfunctioning pain control centres. That ONS is nothing but a symptomatic treatment might be illustrated by the persistent hypothalamic hypermetabolism, which could explain why autonomic attacks may persist despite pain relief and why cluster attacks recur shortly after stimulator arrest. PET studies on larger samples are warranted to confirm these first results. PMID:21349186

  9. A Phenomenological Model of the Electrically Stimulated Auditory Nerve Fiber: Temporal and Biphasic Response Properties

    PubMed Central

    Horne, Colin D. F.; Sumner, Christian J.; Seeber, Bernhard U.

    2016-01-01

    We present a phenomenological model of electrically stimulated auditory nerve fibers (ANFs). The model reproduces the probabilistic and temporal properties of the ANF response to both monophasic and biphasic stimuli, in isolation. The main contribution of the model lies in its ability to reproduce statistics of the ANF response (mean latency, jitter, and firing probability) under both monophasic and cathodic-anodic biphasic stimulation, without changing the model's parameters. The response statistics of the model depend on stimulus level and duration of the stimulating pulse, reproducing trends observed in the ANF. In the case of biphasic stimulation, the model reproduces the effects of pseudomonophasic pulse shapes and also the dependence on the interphase gap (IPG) of the stimulus pulse, an effect that is quantitatively reproduced. The model is fitted to ANF data using a procedure that uniquely determines each model parameter. It is thus possible to rapidly parameterize a large population of neurons to reproduce a given set of response statistic distributions. Our work extends the stochastic leaky integrate and fire (SLIF) neuron, a well-studied phenomenological model of the electrically stimulated neuron. We extend the SLIF neuron so as to produce a realistic latency distribution by delaying the moment of spiking. During this delay, spiking may be abolished by anodic current. By this means, the probability of the model neuron responding to a stimulus is reduced when a trailing phase of opposite polarity is introduced. By introducing a minimum wait period that must elapse before a spike may be emitted, the model is able to reproduce the differences in the threshold level observed in the ANF for monophasic and biphasic stimuli. Thus, the ANF response to a large variety of pulse shapes are reproduced correctly by this model. PMID:26903850

  10. Postural disturbances resulting from unilateral and bilateral diaphragm contractions: a phrenic nerve stimulation study.

    PubMed

    Hamaoui, Alain; Hudson, Anna L; Laviolette, Louis; Nierat, Marie-Cécile; Do, Manh-Cuong; Similowski, Thomas

    2014-10-15

    Thoracoabdominal breathing movements are a complex source of postural disturbance, but there are contradictory reports in the literature with inspiration described as having either a backward or a forward disturbing effect. To elucidate the mechanisms underlying this phenomenon, the present study studied the postural disturbance caused by isolated contractions of the diaphragm. Eight male and four female healthy subjects followed an original paradigm of phrenic nerve stimulation (bilateral and unilateral) and "diaphragmatic" voluntary sniff maneuvers in the seated and standing postures. Center of gravity (CG) acceleration was calculated from force plate recordings, and respiratory kinematics were assessed with thoracic and abdominal sensor belts. CG and respiratory signals revealed that, while seated, bilateral phrenic stimulation and sniff maneuvers consistently produced expansion of the abdomen associated with a forward peak of CG acceleration. In the standing posture, the direction of the CG peak was reversed and always directed backward. Unilateral phrenic stimulation induced an additional medial-lateral acceleration of the CG, directed toward the nonactive side while seated, but in the opposite direction while standing. These results suggest that isolated diaphragmatic contractions produce a constant disturbing pattern for a given posture, but with opposite effects between standing and seated postures. This could be related to the different biomechanical configuration of the body in each posture, corresponding to distinct kinematic patterns of the osteoarticular chain. In addition, the lateral component of the CG acceleration induced by unilateral diaphragm contractions could be clinically relevant in patients with hemidiaphragm paralysis.

  11. Suppression of anodal break excitation by electrical stimulation with down-staircase waveform for distance-selective nerve recruitment.

    PubMed

    Ueno, Ayako; Karashima, Akihiro; Nakao, Mitsuyuki; Katayama, Norihiro

    2012-01-01

    Electrical nerve stimulation using extracellular electrodes is widely performed in clinical medicine as well as basic medical science. It has been reported that selective recruitment of nerve fibers on the basis of the distance between the electrode and the axon is possible without moving the electrode and only by modifying the waveform of electrical stimulation. However, computer simulations have not reproduced the complete nature of the distance-selectivity of the stimulus owing to the difficulty in numerical analysis. In this paper, we propose a minor modification to the myelinated axon model to overcome this difficulty. We confirm that this modification improves the numerical stability of the simulation and enables us to obtain the spatio-temporal dynamics of axons, including the electrode-to-axon distance-dependency. In addition, we propose a novel stimulation method using a down-staircase waveform for distance-selective nerve recruitment. Simulations confirm that the method works well. We show the spatial distribution of axons activated by the down-staircase stimulation, which would be helpful to determine the stimulation parameters for distance-selective nerve recruitment. PMID:23365868

  12. Multi-scale simulations predict responses to non-invasive nerve root stimulation

    NASA Astrophysics Data System (ADS)

    Laakso, Ilkka; Matsumoto, Hideyuki; Hirata, Akimasa; Terao, Yasuo; Hanajima, Ritsuko; Ugawa, Yoshikazu

    2014-10-01

    Objective. Established biophysical neurone models have achieved limited success in reproducing electrophysiological responses to non-invasive stimulation of the human nervous system. This is related to our insufficient knowledge of the induced electric currents inside the human body. Despite the numerous research and clinical applications of non-invasive stimulation, it is still unclear which internal sites are actually affected by it. Approach. We performed multi-scale computer simulations that, by making use of advances in computing power and numerical algorithms, combine a microscopic model of electrical excitation of neurones with a macroscopic electromagnetic model of the realistic whole-body anatomy. Main results. The simulations yield responses consistent with those experimentally recorded following magnetic and electrical motor root stimulation in human subjects, and reproduce the observed amplitudes and latencies for a wide variety of stimulation parameters. Significance. Our findings demonstrate that modern computational techniques can produce detailed predictions about which and where neurones are activated, leading to improved understanding of the physics and basic mechanisms of non-invasive stimulation and enabling potential new applications that make use of improved targeting of stimulation.

  13. Selective recording of electroneurograms from the left vagus nerve of a dog during stimulation of cardiovascular or respiratory systems.

    PubMed

    Rozman, Janez; Ribaric, Samo

    2007-10-31

    Selective electroneurograms (ENGs) from superficial regions of the left vagus nerve of a dog were recorded with a 33-electrode spiral cuff (cuff) implanted on the nerve at the neck in an adult Beagle dog. The electrodes in the cuff were arranged in thirteen groups of three electrodes (GTE 1-13). To identify the relative positions of the particular nerve regions that innervated the heart and lungs, stimulating pulses (2 mA, 200 micros, 20 Hz) were individually delivered to all thirteen GTEs. It was shown that by delivering stimulating pulses to GTEs 4 and 9, heart rate, blood pressure and respiratory rate were modulated. Precisely, only when the stimuli were delivered to GTE 9, the heart rate began to fall and only when the stimuli were delivered to GTE 4 the rate of breathing decreased. To test the selectivity of recording the above-defined groups GTEs 4 and 9 and randomly chosen GTEs 1 and 7 were simultaneously used as recording GTEs while cardio-vascular or respiratory systems were stimulated by carotid artery compression, epinephrine injection and non-invasive, positive end-pressure ventilation. Results showed that stimulations elicited site-specific changes in ENG power spectra recorded from the superficial regions of the vagus nerve. Power spectrum of the ENG recorded with GTE 9, contained frequencies belonging to the neural activity elicited by compression of the carotid artery and injection of epinephrine. The power spectrum of the ENG recorded with GTE 4, contained frequencies belonging to the neural activity elicited by non-invasive, positive end-expiratory pressure ventilation. We concluded that the multi-electrode nerve cuff enables selective stimulation and recording of nerve activity from internal organs.

  14. Peripheral vagus nerve stimulation significantly affects lipid composition and protein secondary structure within dopamine-related brain regions in rats.

    PubMed

    Surowka, Artur Dawid; Krygowska-Wajs, Anna; Ziomber, Agata; Thor, Piotr; Chrobak, Adrian Andrzej; Szczerbowska-Boruchowska, Magdalena

    2015-06-01

    Recent immunohistochemical studies point to the dorsal motor nucleus of the vagus nerve as the point of departure of initial changes which are related to the gradual pathological developments in the dopaminergic system. In the light of current investigations, it is likely that biochemical changes within the peripheral nervous system may influence the physiology of the dopaminergic system, suggesting a putative role for it in the development of neurodegenerative disorders. By using Fourier transform infrared microspectroscopy, coupled with statistical analysis, we examined the effect of chronic, unilateral electrical vagus nerve stimulation on changes in lipid composition and in protein secondary structure within dopamine-related brain structures in rats. It was found that the chronic vagal nerve stimulation strongly affects the chain length of fatty acids within the ventral tegmental area, nucleus accumbens, substantia nigra, striatum, dorsal motor nucleus of vagus and the motor cortex. In particular, the level of lipid unsaturation was found significantly increasing in the ventral tegmental area, substantia nigra and motor cortex as a result of vagal nerve stimulation. When it comes to changes in protein secondary structure, we could see that the mesolimbic, mesocortical and nigrostriatal dopaminergic pathways are particularly affected by vagus nerve stimulation. This is due to the co-occurrence of statistically significant changes in the content of non-ordered structure components, alpha helices, beta sheets, and the total area of Amide I. Macromolecular changes caused by peripheral vagus nerve stimulation may highlight a potential connection between the gastrointestinal system and the central nervous system in rat during the development of neurodegenerative disorders.

  15. Peripheral vagus nerve stimulation significantly affects lipid composition and protein secondary structure within dopamine-related brain regions in rats.

    PubMed

    Surowka, Artur Dawid; Krygowska-Wajs, Anna; Ziomber, Agata; Thor, Piotr; Chrobak, Adrian Andrzej; Szczerbowska-Boruchowska, Magdalena

    2015-06-01

    Recent immunohistochemical studies point to the dorsal motor nucleus of the vagus nerve as the point of departure of initial changes which are related to the gradual pathological developments in the dopaminergic system. In the light of current investigations, it is likely that biochemical changes within the peripheral nervous system may influence the physiology of the dopaminergic system, suggesting a putative role for it in the development of neurodegenerative disorders. By using Fourier transform infrared microspectroscopy, coupled with statistical analysis, we examined the effect of chronic, unilateral electrical vagus nerve stimulation on changes in lipid composition and in protein secondary structure within dopamine-related brain structures in rats. It was found that the chronic vagal nerve stimulation strongly affects the chain length of fatty acids within the ventral tegmental area, nucleus accumbens, substantia nigra, striatum, dorsal motor nucleus of vagus and the motor cortex. In particular, the level of lipid unsaturation was found significantly increasing in the ventral tegmental area, substantia nigra and motor cortex as a result of vagal nerve stimulation. When it comes to changes in protein secondary structure, we could see that the mesolimbic, mesocortical and nigrostriatal dopaminergic pathways are particularly affected by vagus nerve stimulation. This is due to the co-occurrence of statistically significant changes in the content of non-ordered structure components, alpha helices, beta sheets, and the total area of Amide I. Macromolecular changes caused by peripheral vagus nerve stimulation may highlight a potential connection between the gastrointestinal system and the central nervous system in rat during the development of neurodegenerative disorders. PMID:25893743

  16. Transcranial magnetic stimulation studies in the Miller Fisher syndrome: evidence of corticospinal tract abnormality

    PubMed Central

    Lo, Y; Ratnagopal, P

    2001-01-01

    OBJECTIVES—To evaluate serial central motor conduction time in the Miller Fisher syndrome.
METHOD—Three patients with classic Miller Fisher syndrome were evaluated clinically. They had serial central motor conduction times measured with transcranial magnetic stimulation and nerve conduction studies. Motor evoked potentials were recorded from the first dorsal interossei and abductor hallucis muscles.
RESULTS—All three patients showed reduction in central motor conduction times in tandem with gradual clinical improvement at each review.
CONCLUSIONS—There is electrophysiological evidence of a central reversible corticospinal tract conduction abnormality in the Miller Fisher syndrome.

 PMID:11459894

  17. Transcutaneous electrical nerve stimulation offers partial relief in notalgia paresthetica patients with a relevant spinal pathology.

    PubMed

    Savk, Ekin; Savk, Oner; Sendur, Faruk

    2007-05-01

    There is yet no established mode of curative treatment for notalgia paresthetica (NP). We had previously shown a correlation of NP localization with relevant spinal changes which led us to speculate on the possible role of spinal nerve impingement in the pathogenesis of this entity. Based on these findings we aimed to investigate the possible effect of physical therapy in selected cases of NP. Fifteen NP patients with a relevant spinal pathology (four men and 11 women) were included in the study. The mean age was 52.80 +/- 8.83 years (+/- SD; range, 39-73). NP duration was 8.9 +/- 8.13 years (range, 1.5-30). All patients received 10 conventional transcutaneous electrical nerve stimulation (TENS) sessions in the symptomatic area of 20 min duration and high frequency (50-100 Hz). From an initial pruritus score of 10, the mean score by the end of first week was 7.67 +/- 2.02 (range, 5-10) and by the end of second week it was 6.80 +/- 2.73 (range, 4-11). The differences between the pretreatment and post-treatment scores were statistically significant. There was no correlation of therapeutic benefit with age or disease duration. We believe that the partial therapeutic benefit of TENS in NP patients is of importance and further research on the effects of various physical therapeutic modalities would be worthwhile. PMID:17408440

  18. Fully Implantable Peripheral Nerve Stimulation for the Treatment of Hemiplegic Shoulder Pain: A Case Report

    PubMed Central

    Nguyen, Vu Q. C.; Bock, William C.; Groves, Christine C.; Whitney, Marybeth; Bennett, Maria E.; Lechman, Tina E.; Strother, Robert; Grill, Julie H.; Stager, Kathryn W.; Chae, John

    2014-01-01

    This case report describes the first participant treated with a fully-implantable, single-lead peripheral nerve stimulation (PNS) system for refractory hemiplegic shoulder pain (HSP). During the 6-wk trial-stage, a temporary lead was placed percutaneously near the terminal branches of the axillary nerve to the deltoid. The primary outcome measure was the Brief Pain Inventory-Short Form Question 3 (BPI-3), a 0–10 pain numeric rating scale. The participant experienced 75% pain reduction and proceeded to the implant-stage where he received a single-lead, implantable pulse generator. After 3-wks, the participant became pain-free. However, 7-wks after implantation, the system was turned off due to an unrelated acute medical illness. HSP reemerged with BPI-3 of 9. After 11-wks of recovery, PNS was reinitiated and the participant became pain-free through the 9-months follow-up. At 12-months, BPI-3 was a 1. This case report demonstrates the feasibility of a single-lead, fully-implantable PNS system for refractory HSP. PMID:25251248

  19. The therapeutic dilemma of vagus nerve stimulator-induced sleep disordered breathing.

    PubMed

    Upadhyay, Hinesh; Bhat, Sushanth; Gupta, Divya; Mulvey, Martha; Ming, Sue

    2016-01-01

    Intermittent vagus nerve stimulation (VNS) can reduce the frequency of seizures in patients with refractory epilepsy, but can affect respiration in sleep. Untreated obstructive sleep apnea (OSA) can worsen seizure frequency. Unfortunately, OSA and VNS-induced sleep disordered breathing (SDB) may occur in the same patient, leading to a therapeutic dilemma. We report a pediatric patient in whom OSA improved after tonsillectomy, but coexistent VNS-induced SDB persisted. With decrease in VNS output current, patient's SDB improved, but seizure activity exacerbated, which required a return to the original settings. Continuous positive airway pressure titration was attempted, which showed only a partial improvement in apnea-hypopnea index. This case illustrates the need for clinicians to balance seizure control and SDB in patients with VNS. PMID:27168865

  20. The therapeutic dilemma of vagus nerve stimulator-induced sleep disordered breathing

    PubMed Central

    Upadhyay, Hinesh; Bhat, Sushanth; Gupta, Divya; Mulvey, Martha; Ming, Sue

    2016-01-01

    Intermittent vagus nerve stimulation (VNS) can reduce the frequency of seizures in patients with refractory epilepsy, but can affect respiration in sleep. Untreated obstructive sleep apnea (OSA) can worsen seizure frequency. Unfortunately, OSA and VNS-induced sleep disordered breathing (SDB) may occur in the same patient, leading to a therapeutic dilemma. We report a pediatric patient in whom OSA improved after tonsillectomy, but coexistent VNS-induced SDB persisted. With decrease in VNS output current, patient's SDB improved, but seizure activity exacerbated, which required a return to the original settings. Continuous positive airway pressure titration was attempted, which showed only a partial improvement in apnea–hypopnea index. This case illustrates the need for clinicians to balance seizure control and SDB in patients with VNS. PMID:27168865

  1. Chronic pain therapy with transcutaneous electrical nerve stimulation: predictive value of questionnaires.

    PubMed

    Reynolds, A C; Abram, S E; Anderson, R A; Vasudevan, S V; Lynch, N T

    1983-07-01

    A retrospective study of 200 chronic pain patients was conducted to determine whether preexisting physical or social factors influence treatment success with transcutaneous electrical nerve stimulation (TENS). Responses to 30 questions from a preadmission questionnaire were analyzed against short-term treatment success. Patients with pain of more than a year's duration, who had undergone multiple surgical operations for pain control, who used tranquilizers, or who were not working because of pain, demonstrated a generally lower rate of treatment success, although the differences were not statistically significant. Treatment success rate was significantly higher for retired patients than for those with blue-collar jobs or those who were unemployed. There was no association between treatment success rate and site, frequency, character or severity of pain, age, sex, use of narcotic analgesics, or the presence of financial compensation or litigation. The value of TENS for chronic pain remains largely empirical.

  2. Current Approaches to Neuromodulation in Primary Headaches: Focus on Vagal Nerve and Sphenopalatine Ganglion Stimulation.

    PubMed

    Puledda, Francesca; Goadsby, Peter J

    2016-07-01

    Neuromodulation is a promising, novel approach for the treatment of primary headache disorders. Neuromodulation offers a new dimension in the treatment that is both easily reversible and tends to be very well tolerated. The autonomic nervous system is a logical target given the neurobiology of common primary headache disorders, such as migraine and the trigeminal autonomic cephalalgias (TACs). This article will review new encouraging results of studies from the most recent literature on neuromodulation as acute and preventive treatment in primary headache disorders, and cover some possible underlying mechanisms. We will especially focus on vagus nerve stimulation (VNS) and sphenopalatine ganglion (SPG) since they have targeted autonomic pathways that are cranial and can modulate relevant pathophysiological mechanisms. The initial data suggests these approaches will find an important role in headache disorder management going forward.

  3. Mini-coil for magnetic stimulation in the behaving primate.

    PubMed

    Tischler, Hadass; Wolfus, Shuki; Friedman, Alexander; Perel, Eli; Pashut, Tamar; Lavidor, Michal; Korngreen, Alon; Yeshurun, Yosef; Bar-Gad, Izhar

    2011-01-15

    Transcranial magnetic stimulation (TMS) is rapidly becoming a leading method in both cognitive neuroscience and clinical neurology. However, the cellular and network level effects of stimulation are still unclear and their study relies heavily on indirect physiological measurements in humans. Direct electrophysiological studies of the effect of magnetic stimulation on neuronal activity in behaving animals are severely limited by both the size of the stimulating coils, which affect large regions of the animal brain, and the large artifacts generated on the recording electrodes. We present a novel mini-coil which is specifically aimed at studying the neurophysiological mechanism of magnetic stimulation in behaving primates. The mini-coil fits into a chronic recording chamber and provides focal activation of brain areas while enabling simultaneous extracellular multi-electrode recordings. We present a comparison of this coil to a commercial coil based on the theoretical and recorded magnetic fields and induced electric fields they generate. Subsequently, we present the signal recorded in the behaving primate during stimulation and demonstrate the ability to extract the spike trains of multiple single units from each of the electrodes with minimal periods affected by the stimulus artifact (median period <2.5 ms). The directly recorded effect of the magnetic stimulation on cortical neurons is in line with peripheral recordings obtained in humans. This novel mini-coil is a key part of the infrastructure for studying the neurophysiological basis of magnetic stimulation, thereby enabling the development and testing of better magnetic stimulation tools and protocols for both neuroscientists and clinicians. PMID:20974177

  4. Occipital Nerve Stimulation for Chronic Migraine—A Systematic Review and Meta-Analysis

    PubMed Central

    Chen, Yen-Fu; Bramley, George; Unwin, Gemma; Hanu-Cernat, Dalvina; Dretzke, Janine; Moore, David; Bayliss, Sue; Cummins, Carole; Lilford, Richard

    2015-01-01

    Background Chronic migraine is a debilitating headache disorder that has significant impact on quality of life. Stimulation of peripheral nerves is increasingly being used to treat chronic refractory pain including headache disorders. This systematic review examines the effectiveness and adverse effects of occipital nerve stimulation (ONS) for chronic migraine. Methods Databases, including the Cochrane Library, MEDLINE, EMBASE, CINAHL and clinical trial registers were searched to September 2014. Randomized controlled trials (RCTs), other controlled and uncontrolled observational studies and case series (n≥ 10) were eligible. RCTs were assessed using the Cochrane risk of bias tool. Meta-analysis was carried out using a random-effects model. Findings are presented in summary tables and forest plots. Results Five RCTs (total n=402) and seven case series (total n=115) met the inclusion criteria. Pooled results from three multicenter RCTs show that ONS was associated with a mean reduction of 2.59 days (95% CI 0.91 to 4.27, I2=0%) of prolonged, moderate to severe headache per month at 3 months compared with a sham control. Results for other outcomes generally favour ONS over sham controls but quantitative analysis was hampered by incomplete publication and reporting of trial data. Lead migration and infections are common and often require revision surgery. Open-label follow-up of RCTs and case series suggest long-term effectiveness can be maintained in some patients but evidence is limited. Conclusions While the effectiveness of ONS compared to sham control has been shown in multiple RCTs, the average effect size is modest and may be exaggerated by bias as achieving effective blinding remains a methodological challenge. Further measures to reduce the risk of adverse events and revision surgery are needed. Systematic Review Registration this systematic review is an update and expanded work of part of a broader review registered with PROSPERO. Registration No. CRD

  5. Hyposensitivity to nerve stimulation in portal hypertensive rats: role of nitric oxide.

    PubMed

    Sieber, C C; Sumanovski, L T; Moll-Kaufmann, C; Stalder, G A

    1997-11-01

    Portal hypertension goes along with vascular hyporeactivity, partly mediated by nitric oxide (NO). Interactions between the adrenergic nervous system and NO in portal hypertension are undetermined. We tested (1) whether superior mesenteric arterial beds of portal hypertensive rats have an altered sensitivity to periarterial nerve stimulation (PNS) and (2) the role of NO in modulating nerve-stimulated responses. Vasopressor responses to PNS (Hz, 2-32) were similar in preparations of partial portal vein-ligated (PVL, n = 12) and control (CON, n = 12) rats (60.0 +/- 6.7 and 47.8 +/- 6.1 CmH2O respectively) for 24 Hz (NS), but sensitivity of vessels of portal hypertensive animals displayed a significant rightward shift [Hz needed for 50% of maximal response (HZ50) being 15.5 +/- 0.4 and 12.9 +/- 0.6 for PVL and CON respectively, P < 0.001]. NO formation inhibition by N omega-nitro-L-arginine (10(-4) mol L-1) significantly increased responses to PNS (P < 0.05), the absolute values for 24 Hz being 101.4 +/- 11.7 cmH2O for PVL (n = 8) and 86.4 +/- 11.4 cmH2O for CON (n = 7) (NS). NO formation inhibition reversed the hyposensitivity in preparations of PVL, Hz50 being 13.9 +/- 0.5 and 13.2 +/- 0.2 for PVL and CON respectively (NS). Adrenergic receptor antagonism with prazosin (10(-7) mol L-1) and yohimbine (10(-6) mol L-1) inhibited PNS-mediated vasopressor reactivity (n = 6 per group, P < 0.001), confirming the nervous origin of vasoconstrictor responses. It is concluded that (1) portal hypertension goes along with a significant hyposensitivity to PNS and (2) this hyposensitivity is reversed by NO-formation inhibition PMID:9395785

  6. Hyposensitivity to nerve stimulation in portal hypertensive rats: role of nitric oxide.

    PubMed

    Sieber, C C; Sumanovski, L T; Moll-Kaufmann, C; Stalder, G A

    1997-11-01

    Portal hypertension goes along with vascular hyporeactivity, partly mediated by nitric oxide (NO). Interactions between the adrenergic nervous system and NO in portal hypertension are undetermined. We tested (1) whether superior mesenteric arterial beds of portal hypertensive rats have an altered sensitivity to periarterial nerve stimulation (PNS) and (2) the role of NO in modulating nerve-stimulated responses. Vasopressor responses to PNS (Hz, 2-32) were similar in preparations of partial portal vein-ligated (PVL, n = 12) and control (CON, n = 12) rats (60.0 +/- 6.7 and 47.8 +/- 6.1 CmH2O respectively) for 24 Hz (NS), but sensitivity of vessels of portal hypertensive animals displayed a significant rightward shift [Hz needed for 50% of maximal response (HZ50) being 15.5 +/- 0.4 and 12.9 +/- 0.6 for PVL and CON respectively, P < 0.001]. NO formation inhibition by N omega-nitro-L-arginine (10(-4) mol L-1) significantly increased responses to PNS (P < 0.05), the absolute values for 24 Hz being 101.4 +/- 11.7 cmH2O for PVL (n = 8) and 86.4 +/- 11.4 cmH2O for CON (n = 7) (NS). NO formation inhibition reversed the hyposensitivity in preparations of PVL, Hz50 being 13.9 +/- 0.5 and 13.2 +/- 0.2 for PVL and CON respectively (NS). Adrenergic receptor antagonism with prazosin (10(-7) mol L-1) and yohimbine (10(-6) mol L-1) inhibited PNS-mediated vasopressor reactivity (n = 6 per group, P < 0.001), confirming the nervous origin of vasoconstrictor responses. It is concluded that (1) portal hypertension goes along with a significant hyposensitivity to PNS and (2) this hyposensitivity is reversed by NO-formation inhibition

  7. Rates and Predictors of Seizure Freedom With Vagus Nerve Stimulation for Intractable Epilepsy

    PubMed Central

    Rolston, John D.; Wright, Clinton W.; Hassnain, Kevin H.; Chang, Edward F.

    2015-01-01

    BACKGROUND: Neuromodulation-based treatments have become increasingly important in epilepsy treatment. Most patients with epilepsy treated with neuromodulation do not achieve complete seizure freedom, and, therefore, previous studies of vagus nerve stimulation (VNS) therapy have focused instead on reduction of seizure frequency as a measure of treatment response. OBJECTIVE: To elucidate rates and predictors of seizure freedom with VNS. METHODS: We examined 5554 patients from the VNS therapy Patient Outcome Registry, and also performed a systematic review of the literature including 2869 patients across 78 studies. RESULTS: Registry data revealed a progressive increase over time in seizure freedom after VNS therapy. Overall, 49% of patients responded to VNS therapy 0 to 4 months after implantation (≥50% reduction seizure frequency), with 5.1% of patients becoming seizure-free, while 63% of patients were responders at 24 to 48 months, with 8.2% achieving seizure freedom. On multivariate analysis, seizure freedom was predicted by age of epilepsy onset >12 years (odds ratio [OR], 1.89; 95% confidence interval [CI], 1.38-2.58), and predominantly generalized seizure type (OR, 1.36; 95% CI, 1.01-1.82), while overall response to VNS was predicted by nonlesional epilepsy (OR, 1.38; 95% CI, 1.06-1.81). Systematic literature review results were consistent with the registry analysis: At 0 to 4 months, 40.0% of patients had responded to VNS, with 2.6% becoming seizure-free, while at last follow-up, 60.1% of individuals were responders, with 8.0% achieving seizure freedom. CONCLUSION: Response and seizure freedom rates increase over time with VNS therapy, although complete seizure freedom is achieved in a small percentage of patients. ABBREVIATIONS: AED, antiepileptic drug VNS, vagus nerve stimulation PMID:26645965

  8. Developments in deep brain stimulation using time dependent magnetic fields

    NASA Astrophysics Data System (ADS)

    Crowther, L. J.; Nlebedim, I. C.; Jiles, D. C.

    2012-04-01

    The effect of head model complexity upon the strength of field in different brain regions for transcranial magnetic stimulation (TMS) has been investigated. Experimental measurements were used to verify the validity of magnetic field calculations and induced electric field calculations for three 3D human head models of varying complexity. Results show the inability for simplified head models to accurately determine the site of high fields that lead to neuronal stimulation and highlight the necessity for realistic head modeling for TMS applications.

  9. Developments in deep brain stimulation using time dependent magnetic fields

    SciTech Connect

    Crowther, L.J.; Nlebedim, I.C.; Jiles, D.C.

    2012-03-07

    The effect of head model complexity upon the strength of field in different brain regions for transcranial magnetic stimulation (TMS) has been investigated. Experimental measurements were used to verify the validity of magnetic field calculations and induced electric field calculations for three 3D human head models of varying complexity. Results show the inability for simplified head models to accurately determine the site of high fields that lead to neuronal stimulation and highlight the necessity for realistic head modeling for TMS applications.

  10. Mechanisms of magnetic stimulation of central nervous system neurons.

    PubMed

    Pashut, Tamar; Wolfus, Shuki; Friedman, Alex; Lavidor, Michal; Bar-Gad, Izhar; Yeshurun, Yosef; Korngreen, Alon

    2011-03-01

    Transcranial magnetic stimulation (TMS) is a stimulation method in which a magnetic coil generates a magnetic field in an area of interest in the brain. This magnetic field induces an electric field that modulates neuronal activity. The spatial distribution of the induced electric field is determined by the geometry and location of the coil relative to the brain. Although TMS has been used for several decades, the biophysical basis underlying the stimulation of neurons in the central nervous system (CNS) is still unknown. To address this problem we developed a numerical scheme enabling us to combine realistic magnetic stimulation (MS) with compartmental modeling of neurons with arbitrary morphology. The induced electric field for each location in space was combined with standard compartmental modeling software to calculate the membrane current generated by the electromagnetic field for each segment of the neuron. In agreement with previous studies, the simulations suggested that peripheral axons were excited by the spatial gradients of the induced electric field. In both peripheral and central neurons, MS amplitude required for action potential generation was inversely proportional to the square of the diameter of the stimulated compartment. Due to the importance of the fiber's diameter, magnetic stimulation of CNS neurons depolarized the soma followed by initiation of an action potential in the initial segment of the axon. Passive dendrites affect this process primarily as current sinks, not sources. The simulations predict that neurons with low current threshold are more susceptible to magnetic stimulation. Moreover, they suggest that MS does not directly trigger dendritic regenerative mechanisms. These insights into the mechanism of MS may be relevant for the design of multi-intensity TMS protocols, may facilitate the construction of magnetic stimulators, and may aid the interpretation of results of TMS of the CNS. PMID:21455288

  11. Cortical voluntary activation of the human knee extensors can be reliably estimated using transcranial magnetic stimulation.

    PubMed

    Sidhu, Simranjit K; Bentley, David J; Carroll, Timothy J

    2009-02-01

    The objective of this study was to determine if a transcranial magnetic stimulation (TMS) method of quantifying the degree to which the motor cortex drives the muscles during voluntary efforts can be reliably applied to the human knee extensors. Although the technique for estimating "cortical" voluntary activation (VA) is valid and reliable for elbow flexors and wrist extensors, evidence that it can be applied to muscles of the lower limb is necessary if twitch interpolation with TMS is to be widely used in research or clinical practice. Eight subjects completed two identical test sessions involving brief isometric knee extensions at forces ranging from rest to maximal voluntary contraction (MVC). Electromyographic (EMG) responses to TMS of the motor cortex and electrical stimulation of the femoral nerve were recorded from the rectus femoris (RF) and biceps femoris (BF) muscles, and knee extension twitch forces evoked by stimulation were measured. The amplitude of TMS-evoked twitch forces decreased linearly between 25% and 100% MVC (r(2) > 0.9), and produced reliable estimations of resting twitch and VA (ICC(2,1) > 0.85). The reliability and size of cortical measures of VA were comparable to those derived from motor nerve stimulation when the resting twitches were estimated on the basis of as few as three TMS trials. Thus, TMS measures of VA may provide a reliable and valid tool in studies investigating central fatigue due to exercise and neurological deficits in neural drive in the lower limbs. PMID:19034956

  12. The discrepancy between human peripheral nerve chronaxie times as measured using magnetic and electric field stimuli: the relevance to MRI gradient coil safety.

    PubMed

    Recoskie, Bryan J; Scholl, Timothy J; Chronik, Blaine A

    2009-10-01

    Peripheral nerve stimulation (PNS) resulting from electric fields induced from the rapidly changing magnetic fields of gradient coils is a concern in MRI. Nerves exposed to either electric fields or changing magnetic fields would be expected to display consistent threshold characteristics, motivating the direct application of electric field exposure criteria from the literature to guide the development of gradient magnetic field exposure criteria for MRI. The consistency of electric and magnetic field exposures was tested by comparing chronaxie times for electric and magnetic PNS curves for 22 healthy human subjects. Electric and magnetic stimulation thresholds were measured for exposure of the forearm using both surface electrodes and a figure-eight magnetic coil, respectively. The average chronaxie times for the electric and magnetic field conditions were 109 +/- 11 micros and 651 +/- 53 micros (+/-SE), respectively. We do not propose that these results call into question the basic mechanism, namely that rapidly switched gradient magnetic fields induce electric fields in human tissues, resulting in PNS. However, this result does motivate us to suggest that special care must be taken when using electric field exposure data from the literature to set gradient coil PNS safety standards in MRI.

  13. Electrical stimulation promotes nerve cell differentiation on polypyrrole/poly (2-methoxy-5 aniline sulfonic acid) composites

    NASA Astrophysics Data System (ADS)

    Liu, Xiao; Gilmore, Kerry J.; Moulton, Simon E.; Wallace, Gordon G.

    2009-12-01

    The purpose of this work was to investigate for the first time the potential biomedical applications of novel polypyrrole (PPy) composites incorporating a large polyelectrolyte dopant, poly (2-methoxy-5 aniline sulfonic acid) (PMAS). The physical and electrochemical properties were characterized. The PPy/PMAS composites were found to be smooth and hydrophilic and have low electrical impedance. We demonstrate that PPy/PMAS supports nerve cell (PC12) differentiation, and that clinically relevant 250 Hz biphasic current pulses delivered via PPy/PMAS films significantly promote nerve cell differentiation in the presence of nerve growth factor (NGF). The capacity of PPy/PMAS composites to support and enhance nerve cell differentiation via electrical stimulation renders them valuable for medical implants for neurological applications.

  14. Repetitive Adjustment to Estimate the Electric Current Sources in a Nerve Fiber with Magnetic Field Measurement

    NASA Astrophysics Data System (ADS)

    Hayami, Takehito; Mishima, Yukuo; Hiwaki, Osamu

    Magnetic field measuring equipment provides us the way to examine the active position of a peripheral nerve without contact or invasion. To develop a process to estimate the position precisely, simulation study of the magnetic field induced by a myelinated nerve fiber was executed. The electric current sources around the active position of a nerve fiber can be approximated as a pair of electric current dipoles, which represent depolarization and repolarization respectively. Therefore the current sources to estimate from the detected pattern of the magnetic field were modeled as a pair of electric current dipoles. A repetitive adjustment process was proposed as an effective method to find the appropriate positions of the dipoles as the sources of the magnetic fields.

  15. Preferred sites of exocytosis and endocytosis colocalize during high but not lower frequency stimulation in mouse motor nerve terminals

    PubMed Central

    Gaffield, Michael A.; Tabares, Lucia; Betz, William J.

    2010-01-01

    The spatial relationship of exocytosis and endocytosis in motor nerve terminals has been explored, with varied results, mostly in fixed preparations and without direct information on the utilization of each exocytic site. We sought to determine these spatial properties in real time using synaptopHluorin (spH) and FM 4-64. Earlier we showed that nerve stimulation elicits the appearance of spH fluorescence hot spots, which mark preferred sites of exocytosis. Here we show that nerve stimulation in the presence of the styryl dye FM 4-64 evokes hot spots of FM 4-64 fluorescence. Their size, density, and rate of appearance are similar to the spH hot spots, but their rate of disappearance after stimulation was much slower (t½ ∼9 min versus ∼10 s for spH hot spots), consistent with FM 4-64 spots identifying bulk endocytosis and subsequent slow intracellular dispersion of nascent vesicles. Simultaneous imaging of both fluorophores revealed a strong colocalization of spH and FM 4-64 spots, but only during high (100 Hz) stimulation. At 40 Hz stimulation, exo- and endocytic spots did not colocalize. Our results are consistent with the hypothesis that hot spots of endocytosis, possibly in the form of bulk uptake, occur at or very near highly active exocytic sites during high frequency stimulation. PMID:19955383

  16. Diffusion-weighted magnetic resonance imaging of the ulnar nerve in cubital tunnel syndrome.

    PubMed

    Iba, K; Wada, T; Tamakawa, M; Aoki, M; Yamashita, T

    2010-01-01

    Diffusion-weighted images based on magnetic resonance reveal the microstructure of tissues by monitoring the random movement of water molecules. In this study, we investigated whether this new technique could visualize pathologic lesions on ulnar nerve in cubital tunnel. Six elbows in six healthy males without any symptoms and eleven elbows in ten patients with cubital tunnel syndrome underwent on diffusion-weighted MRI. No signal from the ulnar nerve was detected in normal subjects. Diffusion-weighted MRI revealed positive signals from the ulnar nerve in all of the eleven elbows with cubital tunnel syndrome. In contrast, conventional T2W-MRI revealed high signal intensity in eight elbows and low signal intensity in three elbows. Three elbows with low signal MRI showed normal nerve conduction velocity of the ulnar nerve. Diffusion-weighted MRI appears to be an attractive technique for diagnosis of cubital tunnel syndrome in its early stages which show normal electrophysiological and conventional MRI studies.

  17. Effect of Transcutaneous Electrical Nerve Stimulation on Sensation Thresholds in Patients with Painful Diabetic Neuropathy: An Observational Study

    ERIC Educational Resources Information Center

    Moharic, Metka

    2010-01-01

    Transcutaneous electrical nerve stimulation (TENS) is one of the therapies for painful neuropathy. Its analgesic mechanisms probably involve the gate control theory, the physiological block and the endogenous pain inhibitory system. The aim of the study was to determine whether TENS improves small fibre function diminished because of painful…

  18. Incorporation of fiber optic beam shaping into a laparoscopic probe for laser stimulation of the cavernous nerves

    NASA Astrophysics Data System (ADS)

    Tozburun, Serhat; Lagoda, Gwen A.; Mayeh, Mona; Burnett, Arthur L.; Farahi, Faramarz; Fried, Nathaniel M.

    2010-02-01

    The cavernous nerves (CN) course along the prostate surface and are responsible for erectile function. Improved identification and preservation of the CN's is critical to maintaining sexual potency after prostate cancer surgery. Noncontact optical nerve stimulation (ONS) of the CN's was recently demonstrated in a rat model, in vivo, as a potential alternative to electrical nerve stimulation (ENS) for identification of the CN's during prostate surgery. However, the therapeutic window for ONS is narrow, so optimal design of the fiber optic delivery system is critical for safe, reproducible stimulation. This study describes modeling, assembly, and testing of an ONS probe for delivering a small, collimated, flat-top laser beam for uniform CN stimulation. A direct comparison of the magnitude and response time of the intracavernosal pressure (ICP) for both Gaussian and flat-top spatial beam profiles was performed. Thulium fiber laser radiation (λ=1870 nm) was delivered through a 200-μm fiber, with distal fiber tip chemically etched to convert a Gaussian to flat-top beam profile. The laser beam was collimated to a 1-mm-diameter spot using an aspheric lens. Computer simulations of light propagation were used to optimize the probe design. The 10-Fr (3.4-mm-OD) laparoscopic probe provided a constant radiant exposure at the nerve surface. The probe was tested in four rats, in vivo. ONS of the CN's was performed with a 1-mm-diameter spot, 5- ms pulse duration, and pulse rate of 20 Hz for a duration of 15-30 s. The flat-top laser beam profile consistently produced a faster and higher ICP response at a lower radiant exposure than the Gaussian beam profile due, in part, to easier alignment of the more uniform beam with nerve. With further development, ONS may be used as a diagnostic tool for identification of the CN's during laparoscopic and robotic nerve-sparing prostate cancer surgery.

  19. Activity-dependent potentiation and depression of visual cortical responses to optic nerve stimulation in kittens.

    PubMed

    Tamura, H; Tsumoto, T; Hata, Y

    1992-11-01

    1. To see whether long-lasting changes in synaptic efficacy are induced in the developing visual cortex (VC), field potentials evoked by test stimulation given alternatively to each of the optic nerves (ONs) were recorded from VC of kittens ranging in age from 4 to 8 wk. In some experiments, field potentials were recorded simultaneously from the dorsal lateral geniculate nucleus (LGN) in addition to VC. 2. Tetanic stimulation was applied to one of the ONs for 1-60 min at 5 Hz. Homosynaptic potentiation of cortical responses, defined as an increase lasting > 2.5 h in the cortical field potential evoked by test stimulation of the ON that was tetanized, was induced without any changes in LGN responses in 3 of the 12 kittens tested. Heterosynaptic depression, defined as a decrease lasting > 0.5 h in the field potential evoked by stimulation of the ON that was not tetanized, was also induced in two of those three kittens. 3. To elucidate a role of inputs originating from spontaneous activity of retinal ganglion cells in induction of potentiation and depression in the cortex, tetrodotoxin (TTX) was injected into both eyes of 11 kittens. After we confirmed the suppression of retinal activity by TTX, tetanic stimulation was applied to ON. Homosynaptic potentiation of cortical responses was induced in 6 of the 11 kittens, and the ratio of the mean amplitude of posttetanic responses to that of pretetanic responses for the 11 kittens was on average larger than that for the 12 control kittens. Heterosynaptic depression was not observed in any of the 11 kittens. 4. To see a role of postsynaptic activity in induction of potentiation and depression, gamma-aminobutyric acid (GABA) was applied continuously to the VC by an infusion pump in 10 kittens. Tetanic stimulation was given to ON while cortical activities were suppressed by GABA. After recovery of cortical activities, homosynaptic depression was found to be induced in 3 of the 10 kittens, but homosynaptic potentiation was not

  20. Effectiveness of transcutaneous electrical nerve stimulation (TENS) for analgesia during biliary lithotripsy.

    PubMed

    Rawat, B; Genz, A; Fache, J S; Ong, M; Coldman, A J; Burhenne, H J

    1991-10-01

    The effectiveness of transcutaneous electrical nerve stimulation (TENS) in controlling pain during biliary extracorporeal shockwave lithotripsy (BESWL) was assessed in 100 patients with symptomatic gallbladder calculi. Patients were divided into four groups: TENS electrodes were placed on the back at cutaneous anesthesia sites and on the right leg and the gallbladder acupuncture site in groups A and B. Electrodes were "turned on" only in group A. In groups C and D, electrodes were placed only on the back at cutaneous dermatomes. Electrodes were "turned on" in group C only. The TENS unit was stimulated at the pulse rate of 60 to 100 microseconds and frequency of 80 to 125 Hz. Lithotripsy was performed with the Lithostar Plus overhead module. The differences in the amount of analgesic used and the pain experiences by the patients in all groups were not statistically significant. The proportion of patients requiring intravenous analgesia in each group was also not significantly different (72%, 80%, 68%, 76% in groups A to D, respectively). Thus, TENS did not help in reducing the amount of intravenous analgesia required or the average pain perceived by the patient during lithotripsy treatment.

  1. Laryngeal motility alteration: A missing link between sleep apnea and vagus nerve stimulation for epilepsy.

    PubMed

    Zambrelli, Elena; Saibene, Alberto M; Furia, Francesca; Chiesa, Valentina; Vignoli, Aglaia; Pipolo, Carlotta; Felisati, Giovanni; Canevini, Maria Paola

    2016-01-01

    This study aimed to evaluate the prevalence and the relationship of sleep breathing disorders (SBDs) and laryngeal motility alterations in patients with drug-resistant epilepsy after vagus nerve stimulator (VNS) implantation. Twenty-three consecutive patients with medically refractory epilepsy underwent out-of-center sleep testing before and after VNS implantation. Eighteen eligible subjects underwent endoscopic laryngeal examination post-VNS implantation. Statistical analysis was carried out to assess an association between laryngeal motility alterations and the onset/worsening of SBDs. After VNS implantation, 11 patients showed a new-onset mild/moderate SBD. Half of the patients already affected by obstructive sleep apnea (OSA) showed worsening of SBD. All of the patients with a new-onset OSA had a laryngeal pattern with left vocal cord adduction (LVCA) during VNS stimulation. The association between VNS-induced LVCA and SBD was statistically significant. This study suggests an association between VNS and SBD, hinting to a pivotal role of laryngeal motility alterations. The relationship between SBD and VNS-induced LVCA supports the need to routinely investigate sleep respiratory and laryngeal motility patterns before and after VNS implantation.

  2. The effects of transcutaneous electrical nerve stimulation on tissue repair: A literature review

    PubMed Central

    Machado, Aline Fernanda Perez; Santana, Eduardo Ferreira; Tacani, Pascale Mutti; Liebano, Richard Eloin

    2012-01-01

    BACKGROUND: Transcutaneous electrical nerve stimulation (TENS) consists of a generic application of low-frequency, pulsed electrical currents transmitted by electrodes through the skin surface. It is a therapeutic modality that is nonpharmacological, noninvasive, inexpensive, easy to use and widely applied in clinical practice. OBJECTIVE: To narratively review the scientific evidence of the effects of TENS on tissue repair with respect to wound healing, skin flap viability and tendinous repair. METHODS: The study was conducted using the MEDLINE, Lilacs and Scielo databases, without limit to the period of publication, and was completed in November 2011. Inclusion criteria were randomized or nonrandomized, controlled or noncontrolled clinical trials, and experimental trials involving rats subjected to TENS for tissue repair. RESULTS: Thirty articles on tissue repair were found and, among these, 14 reported on wound healing, 14 reported on skin flaps and two analyzed tedinous repair. DISCUSSION: It was suggested that TENS stimulates skin wound healing and tendon repair, as well as the viability of random skin flaps. Such effects may be due to the release of substance P and calcitonin gene-related peptide, which would increase blood flow and, consequently, hasten the events leading to tissue repair. CONCLUSIONS: Based on the scientific evidence regarding the effects of TENS on tissue repair, the findings of the present literature review were inconclusive because data from the randomized controlled clinical trials were insufficient to confirm such effects. PMID:24294017

  3. Vagus nerve stimulation balanced disrupted default-mode network and salience network in a postsurgical epileptic patient

    PubMed Central

    Wang, Kailiang; Chai, Qi; Qiao, Hui; Zhang, Jianguo; Liu, Tinghong; Meng, Fangang

    2016-01-01

    Introduction In recent years, treatment of intractable epilepsy has become more challenging, due to an increase in resistance to antiepileptic drugs, as well as diminished success following resection surgery. Here, we present the case of a 19-year old epileptic patient who received vagus nerve stimulation (VNS) following unsuccessful left parietal–occipital lesion-resection surgery, with results indicating an approximate 50% reduction in seizure frequency and a much longer seizure-free interictal phase. Materials and methods Using resting-state functional magnetic resonance imaging, we measured the changes in resting-state brain networks between pre-VNS treatment and 6 months post-VNS, from the perspective of regional and global variations, using regional homogeneity and large-scale functional connectives (seeding posterior cingulate cortex and anterior cingulate cortex), respectively. Results After 6 months of VNS therapy, the resting-state brain networks were slightly reorganized in regional homogeneity, mainly in large-scale functional connectivity, where excessive activation of the salience network was suppressed, while at the same time the suppressed default-mode network was activated. Conclusion With regard to resting-state brain networks, we propose a hypothesis based on this single case study that VNS acts on intractable epilepsy by modulating the balance between salience and default-mode networks through the integral hub of the anterior cingulate cortex. PMID:27785033

  4. Localization of Interictal Epileptiform Activity Using Magnetoencephalography with Synthetic Aperture Magnetometry in Patients with a Vagus Nerve Stimulator

    PubMed Central

    Stapleton-Kotloski, Jennifer R.; Kotloski, Robert J.; Boggs, Jane A.; Popli, Gautam; O’Donovan, Cormac A.; Couture, Daniel E.; Cornell, Cassandra; Godwin, Dwayne W.

    2014-01-01

    Magnetoencephalography (MEG) provides useful and non-redundant information in the evaluation of patients with epilepsy, and in particular, during the pre-surgical evaluation of pharmaco-resistant epilepsy. Vagus nerve stimulation (VNS) is a common treatment for pharmaco-resistant epilepsy. However, interpretation of MEG recordings from patients with a VNS is challenging due to the severe magnetic artifacts produced by the VNS. We used synthetic aperture magnetometry (g2) [SAM(g2)], an adaptive beamformer that maps the excessive kurtosis, to map interictal spikes to the coregistered MRI image, despite the presence of contaminating VNS artifact. We present a series of eight patients with a VNS who underwent MEG recording. Localization of interictal epileptiform activity by SAM(g2) is compared to invasive electrophysiologic monitoring and other localizing approaches. While the raw MEG recordings were uninterpretable, analysis of the recordings with SAM(g2) identified foci of peak kurtosis and source signal activity that was unaffected by the VNS artifact. SAM(g2) analysis of MEG recordings in patients with a VNS produces interpretable results and expands the use of MEG for the pre-surgical evaluation of epilepsy. PMID:25505894

  5. 3T magnetic resonance neurography of pudendal nerve with cadaveric dissection correlation

    PubMed Central

    Chhabra, Avneesh; McKenna, Courtney A; Wadhwa, Vibhor; Thawait, Gaurav K; Carrino, John A; Lees, Gary P; Dellon, A Lee

    2016-01-01

    AIM To evaluate the pudendal nerve segments that could be identified on magnetic resonance neurography (MRN) before and after surgical marking of different nerve segments. METHODS The hypothesis for this study was that pudendal nerve and its branches would be more easily seen after the surgical nerve marking. Institutional board approval was obtained. One male and one female cadaver pelvis were obtained from the anatomy board and were scanned using 3 Tesla MRI scanner using MR neurography sequences. All possible pudendal nerve branches were identified. The cadavers were then sent to the autopsy lab and were surgically dissected by a peripheral nerve surgeon and an anatomist to identify the pudendal nerve branches. Radiological markers were placed along the course of the pudendal nerve and its branches. The cadavers were then closed and rescanned using the same MRN protocol as the pre-marking scan. The remaining pudendal nerve branches were attempted to be identified using the radiological markers. All scans were read by an experienced musculoskeletal radiologist. RESULTS The pre-marking MR Neurography scans clearly showed the pudendal nerve at its exit from the lumbosacral plexus in the sciatic notch, at the level of the ischial spine and in the Alcock’s Canal in both cadavers. Additionally, the right hemorrhoidal branch could be identified in the male pelvis cadaver. The perineal and distal genital branches could not be identified. On post-marking scans, the markers were used as identifiable structures. The location of the perineal branch, the hemorroidal branch and the dorsal nerve to penis (in male cadaver)/clitoris (in female cadaver) could be seen. However, the visualization of these branches was suboptimal. The contralateral corresponding nerves were poorly seen despite marking on the surgical side. The nerve was best seen on axial T1W and T2W SPAIR images. The proximal segment could be seen well on 3D DW PSIF sequence. T2W SPACE was not very useful in

  6. Sacral Nerve Stimulation For Urinary Urge Incontinence, Urgency-Frequency, Urinary Retention, and Fecal Incontinence

    PubMed Central

    2005-01-01

    Executive Summary Objective The aim of this review was to assess the effectiveness, safety, and cost of sacral nerve stimulation (SNS) to treat urinary urge incontinence, urgency-frequency, urinary retention, and fecal incontinence. Background: Condition and Target Population Urinary urge incontinence, urgency-frequency, urinary retention, and fecal incontinence are prevalent, yet rarely discussed, conditions. They are rarely discussed because patients may be uncomfortable disclosing their symptoms to a health professional or may be unaware that there are treatment options for these conditions. Briefly, urge incontinence is an involuntary loss of urine upon a sudden urge. Urgency-frequency is an uncontrollable urge to void, which results in frequent, small-volume voids. People with urgency-frequency may or may not also experience chronic pelvic pain. Urinary retention refers to the inability to void despite having the urge to void. It can be caused by a hypocontractile detrusor (weak or no bladder muscle contraction) or obstruction due to urethral overactivity. Fecal incontinence is a loss of voluntary bowel control. The prevalence of urge incontinence, urgency-frequency, and urinary retention in the general population is 3.3% to 8.2%, and the prevalence of fecal incontinence is 1.4% to 1.9%. About three-quarters of these people will be successfully treated by behaviour and/or drug therapy. For those who do not respond to these therapies, the options for treatment are management with diapers or pads, or surgery. The surgical procedures are generally quite invasive, permanent, and are associated with complications. Pads and/or diapers are used throughout the course of treatment as different therapies are tried. Patients who respond successfully to treatment may still require pads or diapers, but to a lesser extent. The Technology Being Reviewed: Sacral Nerve Stimulation Sacral nerve stimulation is a procedure where a small device attached to an electrode is

  7. Persistent Increase in Blood Pressure After Renal Nerve Stimulation in Accessory Renal Arteries After Sympathetic Renal Denervation.

    PubMed

    de Jong, Mark R; Hoogerwaard, Annemiek F; Gal, Pim; Adiyaman, Ahmet; Smit, Jaap Jan J; Delnoy, Peter Paul H M; Ramdat Misier, Anand R; van Hasselt, Boudewijn A A M; Heeg, Jan-Evert; le Polain de Waroux, Jean-Benoit; Lau, Elizabeth O Y; Staessen, Jan A; Persu, Alexandre; Elvan, Arif

    2016-06-01

    Blood pressure response to renal denervation is highly variable, and the proportion of responders is disappointing. This may be partly because of accessory renal arteries too small for denervation, causing incomplete ablation. Renal nerve stimulation before and after renal denervation is a promising approach to assess completeness of renal denervation and may predict blood pressure response to renal denervation. The objective of the current study was to assess renal nerve stimulation-induced blood pressure increase before and after renal sympathetic denervation in main and accessory renal arteries of anaesthetized patients with drug-resistant hypertension. The study included 21 patients. Nine patients had at least 1 accessory renal artery in which renal denervation was not feasible. Renal nerve stimulation was performed in the main arteries of all patients and in accessory renal arteries of 6 of 9 patients with accessory arteries, both before and after renal sympathetic denervation. Renal nerve stimulation before renal denervation elicited a substantial increase in systolic blood pressure, both in main (25.6±2.9 mm Hg; P<0.001) and accessory (24.3±7.4 mm Hg; P=0.047) renal arteries. After renal denervation, renal nerve stimulation-induced systolic blood pressure increase was blunted in the main renal arteries (Δ systolic blood pressure, 8.6±3.7 mm Hg; P=0.020), but not in the nondenervated renal accessory renal arteries (Δ systolic blood pressure, 27.1±7.6 mm Hg; P=0.917). This residual source of renal sympathetic tone may result in persistent hypertension after ablation and partly account for the large response variability.

  8. Transcranial Magnetic Stimulation and Volitional Quadriceps Activation

    PubMed Central

    Gibbons, Christopher E.; Pietrosimone, Brian G.; Hart, Joseph M.; Saliba, Susan A.; Ingersoll, Christopher D.

    2010-01-01

    Abstract Context: Quadriceps-activation deficits have been reported after meniscectomy. Transcranial magnetic stimulation (TMS) in conjunction with maximal contractions affects quadriceps activation in patients after meniscectomy. Objective: To determine the effect of single-pulsed TMS on quadriceps central activation ratio (CAR) in patients after meniscectomy. Design: Randomized controlled clinical trial. Setting: University laboratory. Patients or Other Participants: Twenty participants who had partial meniscectomy and who had a CAR less than 85% were assigned randomly to the TMS group (7 men, 4 women; age  =  38.1 ± 16.2 years, height  =  176.8 ± 11.5 cm, mass  =  91.8 ± 27.5 kg, postoperative time  =  36.7 ± 34.9 weeks) or the control group (7 men, 2 women; age  =  38.2 ± 17.5 years, height  =  176.5 ± 7.9 cm, mass  =  86.2 ± 15.3 kg, postoperative time  =  36.6 ± 37.4 weeks). Intervention(s): Participants in the experimental group received TMS over the motor cortex that was contralateral to the involved leg and performed 3 maximal quadriceps contractions with the involved leg. The control group performed 3 maximal quadriceps contractions without the TMS. Main Outcome Measure(s): Quadriceps activation was assessed using the CAR, which was measured in 70° of knee flexion at baseline and at 0, 10, 30, and 60 minutes posttest. The CAR was expressed as a percentage of full activation. Results: Differences in CAR were detected over time (F4,72  =  3.025, P  = .02). No interaction (F4,72  =  1.457, P  =  .22) or between-groups differences (F1,18  =  0.096, P  =  .76) were found for CAR. Moderate CAR effect sizes were found at 10 (Cohen d  =  0.54, 95% confidence interval [CI]  =  −0.33, 1.37) and 60 (Cohen d  =  0.50, 95% CI  =  −0.37, 1.33) minutes in the TMS group compared with CAR at baseline. Strong effect sizes were found for CAR at 10 (Cohen d  =  0.82, 95% CI

  9. The Movement of a Nerve in a Magnetic Field: Application to MRI Lorentz Effect Imaging

    PubMed Central

    Roth, Bradley J.; Luterek, Adam; Puwal, Steffan

    2014-01-01

    Direct detection of neural activity with MRI would be a breakthrough innovation in brain imaging. A Lorentz force method has been proposed to image nerve activity using MRI; a force between the action currents and the static MRI magnetic field causes the nerve to move. In the presence of a magnetic field gradient, this will cause the spins to precess at a different frequency, affecting the MRI signal. Previous mathematical modeling suggests that this effect is too small to explain the experimental data, but that model was limited because the action currents were assumed to be independent of position along the nerve, and because the magnetic field was assumed to be perpendicular to the nerve. In this paper, we calculate the nerve displacement analytically without these two assumptions. Using realistic parameter values, the nerve motion is less than 5 nm, which induced a phase shift in the MRI signal of less than 0.02°. Therefore, our results suggest that Lorentz force imaging is beyond the capabilities of current technology. PMID:24728667

  10. Vagus nerve stimulation mitigates intrinsic cardiac neuronal and adverse myocyte remodeling postmyocardial infarction

    PubMed Central

    Beaumont, Eric; Southerland, Elizabeth M.; Hardwick, Jean C.; Wright, Gary L.; Ryan, Shannon; Li, Ying; KenKnight, Bruce H.; Armour, J. Andrew

    2015-01-01

    This paper aims to determine whether chronic vagus nerve stimulation (VNS) mitigates myocardial infarction (MI)-induced remodeling of the intrinsic cardiac nervous system (ICNS), along with the cardiac tissue it regulates. Guinea pigs underwent VNS implantation on the right cervical vagus. Two weeks later, MI was produced by ligating the ventral descending coronary artery. VNS stimulation started 7 days post-MI (20 Hz, 0.9 ± 0.2 mA, 14 s on, 48 s off; VNS-MI, n = 7) and was compared with time-matched MI animals with sham VNS (MI n = 7) vs. untreated controls (n = 8). Echocardiograms were performed before and at 90 days post-MI. At termination, IC neuronal intracellular voltage recordings were obtained from whole-mount neuronal plexuses. MI increased left ventricular end systolic volume (LVESV) 30% (P = 0.027) and reduced LV ejection fraction (LVEF) 6.5% (P < 0.001) at 90 days post-MI compared with baseline. In the VNS-MI group, LVESV and LVEF did not differ from baseline. IC neurons showed depolarization of resting membrane potentials and increased input resistance in MI compared with VNS-MI and sham controls (P < 0.05). Neuronal excitability and sensitivity to norepinephrine increased in MI and VNS-MI groups compared with controls (P < 0.05). Synaptic efficacy, as determined by evoked responses to stimulating input axons, was reduced in VNS-MI compared with MI or controls (P < 0.05). VNS induced changes in myocytes, consistent with enhanced glycogenolysis, and blunted the MI-induced increase in the proapoptotic Bcl-2-associated X protein (P < 0.05). VNS mitigates MI-induced remodeling of the ICNS, correspondingly preserving ventricular function via both neural and cardiomyocyte-dependent actions. PMID:26276818

  11. Stimulated Brillouin scatter in a magnetized ionospheric plasma.

    PubMed

    Bernhardt, P A; Selcher, C A; Lehmberg, R H; Rodriguez, S P; Thomason, J F; Groves, K M; McCarrick, M J; Frazer, G J

    2010-04-23

    High power electromagnetic waves transmitted from the HAARP facility in Alaska can excite low-frequency electrostatic waves by magnetized stimulated Brillouin scatter. Either an ion-acoustic wave with a frequency less than the ion cyclotron frequency (f(CI)) or an electrostatic ion cyclotron (EIC) wave just above f(CI) can be produced. The coupled equations describing the magnetized stimulated Brillouin scatter instability show that the production of both ion-acoustic and EIC waves is strongly influenced by the wave propagation relative to the background magnetic field. Experimental observations of stimulated electromagnetic emissions using the HAARP transmitter have confirmed that only ion-acoustic waves are excited for propagation along the magnetic zenith and that EIC waves can only be detected with oblique propagation angles. The ion composition can be obtained from the measured EIC frequency. PMID:20482059

  12. Stimulated Brillouin Scatter in a Magnetized Ionospheric Plasma

    SciTech Connect

    Bernhardt, P. A.; Selcher, C. A.; Lehmberg, R. H.; Rodriguez, S. P.; Thomason, J. F.; Groves, K. M.; McCarrick, M. J.; Frazer, G. J.

    2010-04-23

    High power electromagnetic waves transmitted from the HAARP facility in Alaska can excite low-frequency electrostatic waves by magnetized stimulated Brillouin scatter. Either an ion-acoustic wave with a frequency less than the ion cyclotron frequency (f{sub CI}) or an electrostatic ion cyclotron (EIC) wave just above f{sub CI} can be produced. The coupled equations describing the magnetized stimulated Brillouin scatter instability show that the production of both ion-acoustic and EIC waves is strongly influenced by the wave propagation relative to the background magnetic field. Experimental observations of stimulated electromagnetic emissions using the HAARP transmitter have confirmed that only ion-acoustic waves are excited for propagation along the magnetic zenith and that EIC waves can only be detected with oblique propagation angles. The ion composition can be obtained from the measured EIC frequency.

  13. Trigeminal nerve stimulation modulates brainstem more than cortical excitability in healthy humans.

    PubMed

    Mercante, B; Pilurzi, G; Ginatempo, F; Manca, A; Follesa, P; Tolu, E; Deriu, F

    2015-11-01

    Multiple sites in the central nervous system (CNS) have been hypothesized to explain the beneficial effects of transcutaneous trigeminal nerve stimulation (TNS) on several disorders. This work investigated the acute effects of TNS on the excitability of brainstem and intracortical circuits, as well as on sensorimotor integration processes at cortical level in physiological conditions. Brainstem excitability was evaluated in seventeen healthy subjects measuring the R1 and R2 areas of the blink reflex (BR) and its recovery cycle, with cortical excitability and sensorimotor integration assessed by probing short-interval (SICI) and long-interval (LICI) intracortical inhibition, with short-interval (SICF), intracortical facilitation (ICF), short-latency (SAI) and long-latency (LAI) inhibition measuring motor potentials evoked in the first dorsal interosseous muscle by TMS of the contralateral motor cortex. Neurophysiological parameters were assessed, in seventeen healthy subjects, before and after cyclic 20-min TNS delivered bilaterally to the infraorbital nerve. After TNS, the area of the R2 was significantly reduced (p = 0.018). By contrast, R1 area and R2 recovery cycle were unaffected. Similarly, SICI, ICF, LICI, SICF, SAI and LAI appeared unaltered after TNS. These data suggest that, in normal subjects, TNS mainly acts on brainstem polysynaptic circuits mediating the R2 component of the BR and plays a minor role in modifying the activity of higher-level structures involved in the R2 recovery cycle and in modulation of cortical excitability. A further investigation of a chronic TNS-induced effect may disclose a higher potential for TNS in producing measurable after effects on its CNS targets. PMID:26259748

  14. Preventing Phrenic Nerve Stimulation by a Patch Insulation in an Intact Swine Heart Model

    PubMed Central

    Hung, Yi-Wen; Hsieh, Yu-Cheng; Cheng, Chien-Ming; Wang, Kuo-Yang

    2014-01-01

    Introduction Phrenic nerve stimulation (PNS) could be prevented by a silastic patch over the epicardial lead. We studied the effects in preventing PNS by placing a silastic patch directly over an epicardial lead or placing a graft around the phrenic nerve (PN). Methods and Results Fourteen Lanyu swine were enrolled. A bipolar lead was placed epicardially on the left ventricle (LV) inferior to the PN. An implantable cardioverter-defibrillator (ICD) lead was placed into the right ventricle (RV). The maximal influential distance (MID) was measured under 3 pacing configurations to express the influential electrical field on the PN. The threshold of the LV and PN were evaluated epicardially. Then, PTFE patches of different sizes (10×10 mm, 20×20 mm and 30×30 mm) were placed between the LV lead and PN to study the rise in PN threshold in 7 swine. On the other hand, the PN were surrounded by a PTFE graft of different lengths (10 mm, 20 mm, and 30 mm) in the remaining 7 swine. LV-bipolar pacing showed the shortest MID when compared to the other 2 unipolar pacing configurations at pacing voltage of 10 V. The patch was most effective in preventing PNS during LV-bipolar pacing. PNS was prevented under all circumstances with a larger PTFE patch (30×30 mm) or long graft (30 mm). Conclusions PNS was avoided by placing a PTFE patch over the LV lead or a graft around the PN despite pacing configurations. Hence if PNS persisted during CRT implantation, a PTFE patch on the LV lead or a graft around the PN could be considered. PMID:25033271

  15. Magnetic method for stimulating transport in fluids

    DOEpatents

    Martin, James E.; Solis, Kyle J.

    2016-10-18

    A method for producing mass and heat transport in fluids, wherein the method does not rely on conventional convection, that is, it does not require gravity, a thermal gradient, or a magnetic field gradient. This method gives rise to a unique class of vigorous, field-controllable flow patterns termed advection lattices. The advection lattices can be used to transport heat and/or mass in any desired direction using only magnetic fields.

  16. Effect of cerebellar transcranial magnetic stimulation on soleus Ia presynaptic and reciprocal inhibition.

    PubMed

    Matsugi, Akiyoshi; Mori, Nobuhiko; Uehara, Shintaro; Kamata, Noriyuki; Oku, Kosuke; Okada, Yohei; Kikuchi, Yutaka; Mukai, Kouichi; Nagano, Kiyoshi

    2015-02-11

    Previously, we reported that cerebellar transcranial magnetic stimulation (C-TMS) facilitates spinal motoneuronal excitability in resting humans. In this study, we aimed to characterize the descending pathway that is responsible for the C-TMS-associated cerebellar spinal facilitation. We evaluated the effect of C-TMS on ipsilateral soleus Ia presynaptic inhibition (PSI) and reciprocal inhibition (RI) because the vestibulospinal and reticulospinal tracts project from the cerebellum to mediate spinal motoneurons via interneurons associated with PSI. PSI and RI were measured with a soleus H-reflex test following operant conditioning using electrical stimulation of the common peroneal nerve. C-TMS was delivered before test tibial nerve stimulation with conditioning-test interstimulus intervals of 110 ms. C-TMS did not generate motor-evoked potentials, and it did not increase electromyography activity in the ipsilateral soleus muscle, indicating that C-TMS does not directly activate the corticospinal tract and motoneurons. However, C-TMS facilitated the ipsilateral soleus H-reflex and reduced the amount of soleus Ia PSI, but not RI. These findings indicate that C-TMS may facilitate the excitability of the spinal motoneuron pool via the vestibulospinal or reticulospinal tracts associated with PSI. Cerebellar spinal facilitation may be useful for assessing the functional connectivity of the cerebellum and vestibular nuclei or reticular formation. PMID:25569794

  17. Patch-clamp recordings of rat neurons from acute brain slices of the somatosensory cortex during magnetic stimulation

    PubMed Central

    Pashut, Tamar; Magidov, Dafna; Ben-Porat, Hana; Wolfus, Shuki; Friedman, Alex; Perel, Eli; Lavidor, Michal; Bar-Gad, Izhar; Yeshurun, Yosef; Korngreen, Alon

    2014-01-01

    Although transcranial magnetic stimulation (TMS) is a popular tool for both basic research and clinical applications, its actions on nerve cells are only partially understood. We have previously predicted, using compartmental modeling, that magnetic stimulation of central nervous system neurons depolarized the soma followed by initiation of an action potential in the initial segment of the axon. The simulations also predict that neurons with low current threshold are more susceptible to magnetic stimulation. Here we tested these theoretical predictions by combining in vitro patch-clamp recordings from rat brain slices with magnetic stimulation and compartmental modeling. In agreement with the modeling, our recordings demonstrate the dependence of magnetic stimulation-triggered action potentials on the type and state of the neuron and its orientation within the magnetic field. Our results suggest that the observed effects of TMS are deeply rooted in the biophysical properties of single neurons in the central nervous system and provide a framework both for interpreting existing TMS data and developing new simulation-based tools and therapies. PMID:24917788

  18. Motor cortex involvement during choice reaction time: a transcranial magnetic stimulation study in man.

    PubMed

    Romaiguère, P; Possamaï, C A; Hasbroucq, T

    1997-05-01

    It has been shown that transcranial magnetic stimulation can delay simple reaction time; this happens when the stimulation is delivered during the reaction time and over the cortical area which commands the prime mover of the required response. Although it is agreed that magnetic stimulation could be a useful tool for studying information processing in man, we argue that, because of the use of simple reaction time, the results reported so far are difficult to interpret within this theoretical framework. In the present paper, three experiments are reported. Six subjects participated in experiment 1 in which magnetic stimulation was delivered, at different times, during choice reaction time. The effects of the magnetic stimulation of the cortical area involved in the response (induced current passing forward over the motor representation of the responding hand), were compared to the effects of an electrical stimulation of the median nerve (H-reflex). In a first control experiment (experiment 2a; 5 subjects), the coil was placed over the ipsilateral motor cortex (induced current passing backward over the motor representation of the non-responding hand) thus minimizing the probability to excite the same neural nets as in the first experiment. In a second control experiment (experiment 2b; 4 subjects), the coil was placed a few centimeters away from the subject's scalp thus ensuring no stimulation of any neural nets. The results show that: (1) the noise and the smarting of the skin associated with the coil discharge produce an intersensory facilitation thereby shortening reaction time (experiment 2a), (2) actually, the noise produced by the stimulation is sufficient to produce such a facilitatory effect (experiment 2b), (3) a stimulation over the area at the origin of the motor command causes a reaction time delay which counteracts this intersensory facilitation effect (experiment 1), (4) in this latter case, the closer the stimulation to the actual overt response, the

  19. Perinatal taurine exposure programs patterns of autonomic nerve activity responses to tooth pulp stimulation in adult male rats

    PubMed Central

    Khimsuksri, Sawita; Wyss, J. Michael; Thaeomor, Atcharaporn; Paphangkorakit, Jarin; Jirakulsomchok, Dusit; Roysommuti, Sanya

    2016-01-01

    Perinatal taurine excess or deficit influences adult health and disease, especially relative to the autonomic nervous system. This study tests the hypothesis that perinatal taurine exposure influences adult autonomic nervous system control of arterial pressure in response to acute electrical tooth pulp stimulation. Female Sprague-Dawley rats were fed normal rat chow with 3% β-alanine (taurine depletion, TD), 3% taurine (taurine supplementation, TS) or water alone (control, C) from conception to weaning. Their male offspring were fed normal rat chow and tap water throughout the experiment. At 8–10 weeks of age, blood chemistry, arterial pressure, heart rate and renal sympathetic nerve activity were measured in anesthetized rats. Age, body weight, mean arterial pressure, heart rate, plasma electrolytes, blood urea nitrogen, plasma creatinine and plasma cortisol were not significantly different among the three groups. Before tooth pulp stimulation, low (0.3–0.5 Hz) and high frequency (0.5–4.0 Hz) power spectral densities of arterial pressure were not significantly different among groups, while the power spectral densities of renal sympathetic nerve activity were significantly decreased in TD compared to control rats. Tooth pulp stimulation did not change arterial pressure, heart rate, renal sympathetic nerve and arterial pressure power spectral densities in the 0.3–4.0 Hz spectrum or renal sympathetic nerve firing rate in any group. In contrast, perinatal taurine imbalance disturbed very low frequency power spectral densities of both arterial pressure and renal sympathetic nerve activity (below 0.1 Hz), both before and after the tooth pulp stimulation. The power densities of TS were most sensitive to ganglionic blockade and central adrenergic inhibition, while those of TD were sensitive to both central and peripheral adrenergic inhibition. The present data indicate that perinatal taurine imbalance can lead to aberrant autonomic nervous system responses in

  20. A practical guide to diagnostic transcranial magnetic stimulation: Report of an IFCN committee

    PubMed Central

    Groppa, S.; Oliviero, A.; Eisen, A.; Quartarone, A.; Cohen, L.G.; Mall, V.; Kaelin-Lang, A.; Mima, T.; Rossi, S.; Thickbroom, G.W.; Rossini, P.M.; Ziemann, U.; Valls-Solé, J.; Siebner, H.R.

    2016-01-01

    Transcranial magnetic stimulation (TMS) is an established neurophysiological tool to examine the integrity of the fast-conducting corticomotor pathways in a wide range of diseases associated with motor dysfunction. This includes but is not limited to patients with multiple sclerosis, amyotrophic lateral sclerosis, stroke, movement disorders, disorders affecting the spinal cord, facial and other cranial nerves. These guidelines cover practical aspects of TMS in a clinical setting. We first discuss the technical and physiological aspects of TMS that are relevant for the diagnostic use of TMS. We then lay out the general principles that apply to a standardized clinical examination of the fast-conducting corticomotor pathways with single-pulse TMS. This is followed by a detailed description of how to examine corticomotor conduction to the hand, leg, trunk and facial muscles in patients. Additional sections cover safety issues, the triple stimulation technique, and neuropediatric aspects of TMS. PMID:22349304

  1. The sensitivity and selectivity of an implantable two-channel peroneal nerve stimulator system for restoration of dropped foot.

    PubMed

    Kottink, Anke I R; Buschman, Hendrik P J; Kenney, Laurence P J; Veltink, Peter H; Slycke, Per; Bultstra, Gerrit; Hermens, Hermie J

    2004-10-01

    The objective of this study was to evaluate the stimulation responses on each channel of an implantable two-channel stimulator that stimulates the peroneal nerve branches innervating the muscles for dorsiflexion and eversion movements. Currently five Dutch patients and five English patients have been implanted with this system. Isometric ankle torque measurements were carried out in the patient with the longest follow-up period (1 y). A force sensor measured the three components of moment generated at the ankle joint. Stimulation intensity can be adjusted with great accuracy. Dorsiflexion moments are almost entirely determined by the setting of channel 1. Eversion moments are determined mainly by channel 2 and to a lesser extent by channel 1. Both channels determined abduction/adduction moments. We conclude that stimulation responses in both dorsiflexion and eversion direction can be set individually and with great accuracy and are reproducible over a prolonged period. PMID:22151337

  2. Evaluation of heart rate variability in dogs during standard and microburst vagus nerve stimulation: a pilot study.

    PubMed

    Martlé, Valentine; Bavegems, Valérie; Van Ham, Luc; Boon, Paul; Vonck, Kristl; Raedt, Robrecht; Sys, Stanislas; Bhatti, Sofie

    2014-12-01

    Vagus nerve stimulation (VNS) is an established treatment for epilepsy and depression in human patients, but in both humans and dogs, optimal stimulation parameters remain unknown. Delivering afferent bursts of stimulation may be promising as a means of increasing efficacy, but evaluation of potential effects on the heart due to unavoidable efferent stimulation is required. The present study investigated heart rate variability (HRV) in healthy Beagle dogs treated with 1 h of sham, standard or microburst left-sided VNS in a crossover design. No significant differences were found between the stimulation paradigms for any of the cardiac parameters. Short-term left-sided VNS, including a novel bursting pattern (microburst VNS), had no statistically significant effect on HRV in ambulatory healthy dogs. Studies in a larger number of animals with long-term VNS are recommended.

  3. Muscarinic contribution to the acute cortical effects of vagus nerve stimulation

    NASA Astrophysics Data System (ADS)

    Nichols, Justin A.

    2011-12-01

    Electrical stimulation of the vagus nerve (VNS) has been used to treat more than 60,000 patients with drug-resistant epilepsy and is under investigation as a treatment for several other neurological disorders and conditions. Among these, VNS increases memory performance and enhances recovery of motor and cognitive function in animal models of traumatic brain injury. Recent research indicates that pairing brief VNS with tones multiple-times a day for several weeks induces long-term, input specific cortical plasticity, which can be used to re-normalize the pathological cortical reorganization and eliminate a behavioral correlate of chronic tinnitus in noise exposed rats. Despite the therapeutic potential, the mechanisms of action of VNS remain speculative. In chapter 2 of this dissertation, the acute effects of VNS on cortical synchrony, excitability, and temporal processing are examined. In anesthetized rats implanted with multi-electrode arrays, VNS increased and decorrelated spontaneous multi-unit activity, and suppressed entrainment to repetitive noise burst stimulation at 6 to 8 Hz, but not after systemic administration of the muscarinic antagonist scopolamine. Chapter 3 focuses on VNS-tone pairing induced cortical plasticity. Pairing VNS with a tone one hundred times in anesthetized rats resulted in frequency specific plasticity in 31% of the auditory cortex sites. Half of these sites exhibited a frequency specific increase in firing rate and half exhibited a frequency specific decrease. Muscarinic receptor blockade with scopolamine almost entirely prevented the frequency specific increases, but not decreases. Collectively, these experiments demonstrate the capacity for VNS to not only acutely influence cortical synchrony, and excitability, but to also influence temporal and spectral tuning via muscarinic receptor activation. These results strengthen the hypothesis that acetylcholine and muscarinic receptors are involved in the mechanisms of action of VNS and

  4. Effects of different frequencies of transcutaneous electrical nerve stimulation on venous vascular reactivity

    PubMed Central

    Franco, O.S.; Paulitsch, F.S.; Pereira, A.P.C.; Teixeira, A.O.; Martins, C.N.; Silva, A.M.V.; Plentz, R.D.M.; Irigoyen, M.C.; Signori, L.U.

    2014-01-01

    Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 μs) and high frequency (100 Hz/200 μs) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of α1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia. PMID:24820225

  5. Effects of different frequencies of transcutaneous electrical nerve stimulation on venous vascular reactivity.

    PubMed

    Franco, O S; Paulitsch, F S; Pereira, A P C; Teixeira, A O; Martins, C N; Silva, A M V; Plentz, R D M; Irigoyen, M C; Signori, L U

    2014-05-01

    Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 μs) and high frequency (100 Hz/200 μs) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of α1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia.

  6. Vagal nerve stimulation reverses aberrant dopamine system function in the methylazoxymethanol acetate rodent model of schizophrenia.

    PubMed

    Perez, Stephanie M; Carreno, Flavia R; Frazer, Alan; Lodge, Daniel J

    2014-07-01

    Vagal nerve stimulation (VNS) is an alternative therapy for epilepsy and treatment refractory depression. Here we examine VNS as a potential therapy for the treatment of schizophrenia in the methylozoxymethanol acetate (MAM) rodent model of the disease. We have previously demonstrated that hyperactivity within ventral regions of the hippocampus (vHipp) drives the dopamine system dysregulation in this model. Moreover, by targeting the vHipp directly, we can reverse aberrant dopamine system function and associated behaviors in the MAM model. Although the central effects of VNS have not been completely delineated, positron emission topographic measurements of cerebral blood flow in humans have consistently reported that VNS stimulation induces bilateral decreases in hippocampal activity. Based on our previous observations, we performed in vivo extracellular electrophysiological recordings in MAM- and saline-treated rats to evaluate the effect of chronic (2 week) VNS treatment on the activity of putative vHipp pyramidal neurons, as well as downstream dopamine neuron activity in the ventral tegmental area. Here we demonstrate that chronic VNS was able to reverse both vHipp hyperactivity and aberrant mesolimbic dopamine neuron function in the MAM model of schizophrenia. Additionally, VNS reversed a behavioral correlate of the positive symptoms of schizophrenia. Because current therapies for schizophrenia are far from adequate, with a large number of patients discontinuing treatment due to low efficacy or intolerable side effects, it is important to explore alternative nonpharmacological treatments. These data provide the first preclinical evidence that VNS may be a possible alternative therapeutic approach for the treatment of schizophrenia.

  7. [High resolution 3T magnetic resonance neurography of the peroneal nerve].

    PubMed

    Pineda, D; Barroso, F; Cháves, H; Cejas, C

    2014-01-01

    Peroneal neuropathy is the most common mononeuropathy of the lower limbs. The causes of peroneal neuropathy include trauma, tumors of the nerve and nerve sheath, entrapment, and others like perineurioma, fibromatosis, lymphoma, and intraneural and externeural ganglia. The diagnosis is based on clinical manifestations and electrophysiological studies. Nowadays, however, magnetic resonance (MR) neurography is a complementary diagnostic technique that can help determine the location and cause of peroneal neuropathy. In this article, we describe the MR anatomy of the peroneal nerve, its relations, and the muscles it innervates. We also discuss the clinical and electrophysiological manifestations of peroneal neuropathy, describe the technical parameters used at our institution, and illustrate the MR appearance of various diseases that involve the peroneal nerve.

  8. Transcutaneous Electrical Nerve Stimulation for Management of Limb Spasticity: A Systematic Review.

    PubMed

    Mills, Patricia Branco; Dossa, Farhana

    2016-04-01

    The purpose of this systematic review was to summarize the effect of transcutaneous electrical nerve stimulation (TENS) for management of limb spasticity. Randomized controlled trials were searched using electronic databases through July 2015. Fourteen randomized controlled trials were included, involving 544 participants. Intervention protocols fit within three categories: 1) TENS vs. no TENS or placebo TENS (n = 7), 2) TENS vs. another TENS protocol or another intervention for spasticity management (n = 7), and 3) TENS as an adjunct to another intervention for spasticity management (n = 4). There was level 1 and 2 evidence for TENS improving spasticity-related outcome measures within the International Classification of Functioning, Disability, and Health domains of body structure and function (e.g., Modified Ashworth Scale) as well as activity (e.g., gait). Better responses in outcome measures in the International Classification of Functioning, Disability, and Health activity domain were seen when TENS was used in combination with active therapy (e.g., exercise and task-related training) vs. as a single therapeutic modality. PMID:26829077

  9. Low Intensity Laser Therapy (LILT) Versus Transcutaneous Electrical Nerve Stimulation On Microcirculation In Diabetic Neuropathy

    NASA Astrophysics Data System (ADS)

    Battecha, Kadria H.; Atya, Azza M.

    2011-09-01

    Reduced microcirculation is a morbid element of neuropathy and one of the most common complications of uncontrolled diabetes. Many physical modalities have gained a considerable attention for enhancing cutaneous microcirculation in diabetic patients and prevent its serious complications. Accordingly, the present study was conducted to compare between the effect of low intensity laser therapy (LILT) and transcutaneous electrical nerve stimulation (TENS) on microcirculation in diabetic neuropathy. Thirty diabetic polyneuropathic patients ranged in age from 45-60 years participated in this study. They were randomly divided into two groups of equal number; patients in group (A) received LILT on plantar surface of foot with a dose of 3 J/cm2 and wavelength (904 nm), while those in group (B) received TENS on lower leg for 30 minutes with frequency (2 HZ). Treatment was conducted 3 times/week for 6 weeks. The cutaneous microcirculation was evaluated by Laser Doppler flowmetry at the baseline and at the end of treatment. Results revealed that group (A) showed statistically significant increase in the cutaneous microcirculation compared with group (B). So, it was concluded that LILT has to be more efficient than TENS in increasing cutaneous microcirculation in patients with diabetic neuropathy.

  10. Clinical Efficacy in the Treatment of Overactive Bladder Refractory to Anticholinergics by Posterior Tibial Nerve Stimulation

    PubMed Central

    Palao-Yago, Francisco; Campon-Pacheco, Iluminada; Martinez-Sanchez, Maribel; Zuluaga-Gomez, Armando; Arrabal-Martin, Miguel

    2012-01-01

    Purpose Overactive bladder (OAB) is a clinical syndrome that is currently treated initially with anticholinergics, although some other therapeutic alternatives exist, such as neuromodulation, botulinum toxin, and posterior tibial nerve stimulation (PTNS). The purpose of this study was to assess the efficacy of PTNS in patients with OAB refractory to anticholinergics. Materials and Methods We present a cohort study of 14 women with OAB to whom we applied PTNS. We assessed (before and after the treatment) the diurnal micturitional frequency, the nocturnal micturitional frequency, urgency episodes, and urge incontinence episodes. Results were analyzed by using the Wilcoxon test for nonparametric samples. Results We observed statistically significant improvement in the diurnal micturitional frequency (p=0.05), in episodes of micturitional urgency (p=0.03), and in episodes of urge incontinence (p=0.004). A total of 50% of the patients felt subjective improvement from their pathology. Conclusions PTNS is a valid, minimally invasive treatment option with minimum morbidity for patients with OAB refractory to treatment with anticholinergics. PMID:22866220

  11. [Variations in the configuration of somatosensory evoked potentials following stimulation of the median nerve].

    PubMed

    Strenge, H

    1989-09-01

    The variants of waveform patterns of cervical and cortical somatosensory evoked potentials to median nerve stimulation at the wrist were analysed in 86 normal subjects aged 15 to 71 years. In cervical SEP recordings the components N13, N14 and the trough-shaped variant of P17 showed the highest short-term stability. Immediate changes of the amplitude proportions of subcomponents within the potential, i.e. a lack of uniformity in waveforms, have to be considered normal. Significant associations were found between the occurrence of components N14 and an arm length of more than 68 cm and between the appearance of a plateau configuration of P17 and an age of at least 40 years. Considering definite criteria the latency of P17 can be used as an additional reliable parameter. In cortical SEP recordings the combination of an initial V-shaped pattern and a following bifid W-configuration appeared as the most frequent waveform profile. All parts of the potential but the positive waves of the primary complex revealed a high intraindividual stability. PMID:2507276

  12. Exogenous nerve growth factor stimulates choline acetyltransferase activity in aging Fischer 344 male rats.

    PubMed

    Williams, L R

    1991-01-01

    The effect of age and exogenous nerve growth factor (NGF) infusion on choline acetyltransferase (ChAT) specific activity is examined in microdissections of cerebral and hippocampal cortices, and the cholinergic nuclei of the medial septum and diagonal band of Broca (MS/DB), the nucleus basalis magnocellularis (NBM), and striatum of Fischer 344 male rats. Significant, 20% losses in ChAT activity are found in the MS/DB and striatum of 24-month-old rats (n = 21) compared to 4-month-old animals, but there is no apparent loss of enzyme activity in the NBM. Loss of ChAT activity in the MS/DB is only observed in animals older than 19 months of age, while a striatal deficit is found in animals older than 7 months. Treatment for 2 weeks with NGF at 1.2 micrograms/day results in significant 70% increases of ChAT activity in the MS/DB and striatum of 24-month-old rats compared to untreated and vehicle-treated 4-month-old rats, but does not stimulate activity in the NBM. Sensitivity of ChAT activity in the MS/DB and striatum to exogenous NGF increases with age. These experiments indicate that in the MS/DB, NBM, and striatum of Fischer 344 male rat there is an age-associated, differential regulation of ChAT enzyme activity and sensitivity to exogenous NGF.

  13. Comparison of Transcutaneous Electrical Nerve Stimulation and Parasternal Block for Postoperative Pain Management after Cardiac Surgery.

    PubMed

    Ozturk, Nilgun Kavrut; Baki, Elif Dogan; Kavakli, Ali Sait; Sahin, Ayca Sultan; Ayoglu, Raif Umut; Karaveli, Arzu; Emmiler, Mustafa; Inanoglu, Kerem; Karsli, Bilge

    2016-01-01

    Background. Parasternal block and transcutaneous electrical nerve stimulation (TENS) have been demonstrated to produce effective analgesia and reduce postoperative opioid requirements in patients undergoing cardiac surgery. Objectives. To compare the effectiveness of TENS and parasternal block on early postoperative pain after cardiac surgery. Methods. One hundred twenty patients undergoing cardiac surgery were enrolled in the present randomized, controlled prospective study. Patients were assigned to three treatment groups: parasternal block, intermittent TENS application, or a control group. Results. Pain scores recorded 4 h, 5 h, 6 h, 7 h, and 8 h postoperatively were lower in the parasternal block group than in the TENS and control groups. Total morphine consumption was also lower in the parasternal block group than in the TENS and control groups. It was also significantly lower in the TENS group than in the control group. There were no statistical differences among the groups regarding the extubation time, rescue analgesic medication, length of intensive care unit stay, or length of hospital stay. Conclusions. Parasternal block was more effective than TENS in the management of early postoperative pain and the reduction of opioid requirements in patients who underwent cardiac surgery through median sternotomy. This trial is registered with Clinicaltrials.gov number NCT02725229. PMID:27445610

  14. Vagus Nerve Stimulation as a Tool to Induce Plasticity in Pathways Relevant for Extinction Learning.

    PubMed

    Childs, Jessica E; Alvarez-Dieppa, Amanda C; McIntyre, Christa K; Kroener, Sven

    2015-08-21

    Extinction describes the process of attenuating behavioral responses to neutral stimuli when they no longer provide the reinforcement that has been maintaining the behavior. There is close correspondence between fear and human anxiety, and therefore studies of extinction learning might provide insight into the biological nature of anxiety-related disorders such as post-traumatic stress disorder, and they might help to develop strategies to treat them. Preclinical research aims to aid extinction learning and to induce targeted plasticity in extinction circuits to consolidate the newly formed memory. Vagus nerve stimulation (VNS) is a powerful approach that provides tight temporal and circuit-specific release of neurotransmitters, resulting in modulation of neuronal networks engaged in an ongoing task. VNS enhances memory consolidation in both rats and humans, and pairing VNS with exposure to conditioned cues enhances the consolidation of extinction learning in rats. Here, we provide a detailed protocol for the preparation of custom-made parts and the surgical procedures required for VNS in rats. Using this protocol we show how VNS can facilitate the extinction of conditioned fear responses in an auditory fear conditioning task. In addition, we provide evidence that VNS modulates synaptic plasticity in the pathway between the infralimbic (IL) medial prefrontal cortex and the basolateral complex of the amygdala (BLA), which is involved in the expression and modulation of extinction memory.

  15. Vagus Nerve Stimulation as a Tool to Induce Plasticity in Pathways Relevant for Extinction Learning

    PubMed Central

    Childs, Jessica E.; Alvarez-Dieppa, Amanda C.; McIntyre, Christa K.; Kroener, Sven

    2015-01-01

    Extinction describes the process of attenuating behavioral responses to neutral stimuli when they no longer provide the reinforcement that has been maintaining the behavior. There is close correspondence between fear and human anxiety, and therefore studies of extinction learning might provide insight into the biological nature of anxiety-related disorders such as post-traumatic stress disorder, and they might help to develop strategies to treat them. Preclinical research aims to aid extinction learning and to induce targeted plasticity in extinction circuits to consolidate the newly formed memory. Vagus nerve stimulation (VNS) is a powerful approach that provides tight temporal and circuit-specific release of neurotransmitters, resulting in modulation of neuronal networks engaged in an ongoing task. VNS enhances memory consolidation in both rats and humans, and pairing VNS with exposure to conditioned cues enhances the consolidation of extinction learning in rats. Here, we provide a detailed protocol for the preparation of custom-made parts and the surgical procedures required for VNS in rats. Using this protocol we show how VNS can facilitate the extinction of conditioned fear responses in an auditory fear conditioning task. In addition, we provide evidence that VNS modulates synaptic plasticity in the pathway between the infralimbic (IL) medial prefrontal cortex and the basolateral complex of the amygdala (BLA), which is involved in the expression and modulation of extinction memory. PMID:26325100

  16. Two-year outcome of vagus nerve stimulation in treatment-resistant depression.

    PubMed

    Bajbouj, Malek; Merkl, Angela; Schlaepfer, Thomas E; Frick, Caroline; Zobel, Astrid; Maier, Wolfgang; O'Keane, Veronica; Corcoran, Ciaran; Adolfsson, Rolf; Trimble, Michael; Rau, Harald; Hoff, Hans-Joachim; Padberg, Frank; Müller-Siecheneder, Florian; Audenaert, Kurt; van den Abbeele, Dirk; Matthews, Keith; Christmas, David; Eljamel, Sam; Heuser, Isabella

    2010-06-01

    One of the major goals of antidepressant treatment is a sustained response and remission of depressive symptoms. Some of the previous studies of vagus nerve stimulation (VNS) have suggested antidepressant effects. Our naturalistic study assessed the efficacy and the safety of VNS in 74 European patients with therapy-resistant major depressive disorder. Psychometric measures were obtained after 3, 12, and 24 months of VNS. Mixed-model repeated-measures analysis of variance revealed a significant reduction (P < or = 0.05) at all the 3 time points in the 28-item Hamilton Rating Scale for Depression (HRSD28) score, the primary outcome measure. After 2 years, 53.1% (26/49) of the patients fulfilled the response criteria (> or =50% reduction in the HRSD28 scores from baseline) and 38.9% (19/49) fulfilled the remission criteria (HRSD28 scores < or = 10). The proportion of patients who fulfilled the remission criteria remained constant as the duration of VNS treatment increased. Voice alteration, cough, and pain were the most frequently reported adverse effects. Two patients committed suicide during the study; no other deaths were reported. No statistically significant differences were seen in the number of concomitant antidepressant medications. The results of this 2-year open-label trial suggest a clinical response and a comparatively benign adverse effect profile among patients with treatment-resistant depression.

  17. The sweet taste in the calf. I. Chorda tympani proper nerve responses to taste stimulation of the tongue.

    PubMed

    Segerstad, C H; Hellekant, G

    1989-03-01

    Electrophysiological recordings were obtained from the chorda tympani nerve in calves during stimulation with NaCl, quinine hydrochloride, citric acid, acesulfan-K, aspartame, fructose, galactose, glucose, glycine, lactose, maltose, monellin, Na-saccharin, sucrose, thaumatin, and xylitol. In cattle the chorda tympani innervates the posterior third of the tongue as well as the anterior part. It was found that the posterior receptive field generally responded better to sweet substances than the anterior. Glycine and Na-saccharin followed by xylitol were the most effective sweet stimuli. The monosaccharides elicited larger responses than the disaccharides. Aspartame gave a weak nerve response in 5 of 13 calves. Monellin and thaumatin elicited no change in chorda tympani nerve activity and did not crossadapt with any sweetener. No effects on citric acid responses were observed after application of miraculin. PMID:2756056

  18. The sweet taste in the calf. I. Chorda tympani proper nerve responses to taste stimulation of the tongue.

    PubMed

    Segerstad, C H; Hellekant, G

    1989-03-01

    Electrophysiological recordings were obtained from the chorda tympani nerve in calves during stimulation with NaCl, quinine hydrochloride, citric acid, acesulfan-K, aspartame, fructose, galactose, glucose, glycine, lactose, maltose, monellin, Na-saccharin, sucrose, thaumatin, and xylitol. In cattle the chorda tympani innervates the posterior third of the tongue as well as the anterior part. It was found that the posterior receptive field generally responded better to sweet substances than the anterior. Glycine and Na-saccharin followed by xylitol were the most effective sweet stimuli. The monosaccharides elicited larger responses than the disaccharides. Aspartame gave a weak nerve response in 5 of 13 calves. Monellin and thaumatin elicited no change in chorda tympani nerve activity and did not crossadapt with any sweetener. No effects on citric acid responses were observed after application of miraculin.

  19. Nerve Conduction Block Using Combined Thermoelectric Cooling and High Frequency Electrical Stimulation

    PubMed Central

    Ackermann, D. Michael; Foldes, Emily L.; Bhadra, Niloy; Kilgore, Kevin L.

    2010-01-01

    Conduction block of peripheral nerves is an important technique for many basic and applied neurophysiology studies. To date, there has not been a technique which provides a quickly initiated and reversible “on-demand” conduction block which is both sustainable for long periods of time and does not generate activity in the nerve at the onset of the conduction block. In this study we evaluated the feasibility of a combined method of nerve block which utilizes two well established nerve blocking techniques in a rat and cat model: nerve cooling and electrical block using high frequency alternating currents (HFAC). This combined method effectively makes use of the contrasting features of both nerve cooling and electrical block using HFAC. The conduction block was initiated using nerve cooling, a technique which does not produce nerve “onset response” firing, a prohibitive drawback of HFAC electrical block. The conduction block was then readily transitioned into an electrical block. A long-term electrical block is likely preferential to a long-term nerve cooling block because nerve cooling block generates large amounts of exhaust heat, does not allow for fiber diameter selectivity and is known to be unsafe for prolonged delivery. PMID:20705099

  20. Nerve conduction block using combined thermoelectric cooling and high frequency electrical stimulation.

    PubMed

    Ackermann, D Michael; Foldes, Emily L; Bhadra, Niloy; Kilgore, Kevin L

    2010-10-30

    Conduction block of peripheral nerves is an important technique for many basic and applied neurophysiology studies. To date, there has not been a technique which provides a quickly initiated and reversible "on-demand" conduction block which is both sustainable for long periods of time and does not generate activity in the nerve at the onset of the conduction block. In this study we evaluated the feasibility of a combined method of nerve block which utilizes two well established nerve blocking techniques in a rat and cat model: nerve cooling and electrical block using high frequency alternating currents (HFAC). This combined method effectively makes use of the contrasting features of both nerve cooling and electrical block using HFAC. The conduction block was initiated using nerve cooling, a technique which does not produce nerve "onset response" firing, a prohibitive drawback of HFAC electrical block. The conduction block was then readily transitioned into an electrical block. A long-term electrical block is likely preferential to a long-term nerve cooling block because nerve cooling block generates large amounts of exhaust heat, does not allow for fiber diameter selectivity and is known to be unsafe for prolonged delivery.

  1. Recovery of function after vagus nerve stimulation initiated 24 hours after fluid percussion brain injury.

    PubMed

    Smith, Douglas C; Tan, Arlene A; Duke, Andrea; Neese, Steven L; Clough, Richard W; Browning, Ronald A; Jensen, Robert A

    2006-10-01

    Recent evidence from our laboratory demonstrated in laboratory rats that stimulation of the vagus nerve (VNS) initiated 2 h after lateral fluid percussion brain injury (FPI) accelerates the rate of recovery on a variety of behavioral and cognitive tests. VNS animals exhibited a level of performance comparable to that of sham-operated uninjured animals by the end of a 2-week testing period. The effectiveness of VNS was further evaluated in the present study in which initiation of stimulation was delayed until 24 h post-injury. Rats were subjected to a moderate FPI and tested on the beam walk, skilled forelimb reaching, locomotor placing, forelimb flexion and Morris water maze tasks for 2 weeks following injury. VNS (30 sec trains of 0.5 mA, 20.0-Hz biphasic pulses) was initiated 24 h post-injury and continued at 30-min intervals for the duration of the study, except for brief periods when the animals were detached for behavioral assessments. Consistent with our previous findings when stimulation was initiated 2 h post-injury, VNS animals showed significantly faster rates of recovery compared to controls. By the last day of testing (day 14 post-injury), the FPI-VNS animals were performing significantly better than the FPI-no-VNS animals and were not significantly different from shams in all motor and sensorimotor tasks. Performance in the Morris water maze indicated that the VNS animals acquired the task more rapidly on days 11-13 post-injury. On day 14, the FPI-VNS animals did not differ in the latency to find the platform from sham controls, whereas the injured controls did; however, the FPI-VNS animals and injured controls were not significantly different. Despite the lack of significant histological differences between the FPI groups, VNS, when initiated 24 h following injury, clearly attenuated the ensuing behavioral deficits and enhanced acquisition of the cognitive task. The results are discussed with respect to the norepinephrine hypothesis. PMID:17020489

  2. ANALYSIS OF THE STRUCTURE OF MAGNETIC FIELDS THAT INDUCED INHIBITION OF STIMULATED NEURITE OUTGROWTH

    EPA Science Inventory

    The important experiments showing nonlinear amplitude dependences of the neurite outgrowth in pheochromocytoma nerve cells due to ELF magnetic field exposure had been carried out in a nonuniform ac magnetic field. The nonuniformity entailed larger than expected variances in magne...

  3. Sacral neuromodulation and peripheral nerve stimulation in patients with anal incontinence: an overview of techniques, complications and troubleshooting

    PubMed Central

    Zbar, Andrew P.

    2014-01-01

    Sacral neuromodulation (SNM) therapy has revolutionized the management of many forms of anal incontinence, with an expanded use and a medium-term efficacy of 75% overall. This review discusses the technique of SNM therapy, along with its complications and troubleshooting and a discussion of the early data pertaining to peripheral posterior tibial nerve stimulation in incontinent patients. Future work needs to define the predictive factors for neurostimulatory success, along with the likely mechanisms of action of their therapeutic action. PMID:24759349

  4. On-off closed-loop control of vagus nerve stimulation for the adaptation of heart rate.

    PubMed

    Ugalde, Hector Romero; Le Rolle, Virginie; Bel, Alain; Bonnet, Jean-Luc; Andreu, David; Mabo, Philippe; Carrault, Guy; Hernández, Alfredo I

    2014-01-01

    Vagus nerve stimulation (VNS) is a potential therapeutic approach in a number of clinical applications. Although VNS is commonly delivered in an open-loop approach, it is now recognized that closed-loop approaches may be necessary to optimize the therapy and minimize side effects of neuro-stimulation devices. In this paper, we describe a prototype system for real-time control of the instantaneous heart rate, working synchronously with the heart period. As a first step, an on-off control method has been integrated. The system is evaluated on one sheep with induced heart failure, showing the interest of the proposed approach.

  5. Electrical stimulation of the vagus nerve enhances cognitive and motor recovery following moderate fluid percussion injury in the rat.

    PubMed

    Smith, Douglas C; Modglin, Arlene A; Roosevelt, Rodney W; Neese, Steven L; Jensen, Robert A; Browning, Ronald A; Clough, Richard W

    2005-12-01

    Intermittent, chronically delivered electrical stimulation of the vagus nerve (VNS) is an FDA-approved procedure for the treatment of refractory complex/partial epilepsy in humans. Stimulation of the vagus has also been shown to enhance memory storage processes in laboratory rats and human subjects. Recent evidence suggests that some of these effects of VNS may be due to the activation of neurons in the nucleus locus coeruleus resulting in the release of norepinephrine (NE) throughout the neuraxis. Because antagonism of NE systems has been shown to delay recovery of function following brain damage, it is possible that enhanced release of NE in the CNS may facilitate recovery of function. To evaluate this hypothesis the lateral fluid percussion injury (LFP) model of traumatic brain injury was used and a variety of motor and cognitive behavioral tests were employed to assess recovery in pre-trained stimulated, control, and sham-injured laboratory rats. Two hours following moderate LFP, vagus nerve stimulation (30.0-sec trains of 0.5 mA, 20.0 Hz, biphasic pulses) was initiated. Stimulation continued in each animal's home cage at 30-min intervals for a period of 14 days, with the exception of brief periods when the animals were disconnected for behavioral assessments. Motor behaviors were evaluated every other day following LFP and tests included beam walk, locomotor placing, and skilled forelimb reaching. In each measure an enhanced rate of recovery and /or level of final performance was observed in the VNS-LFP animals compared to nonstimulated LFP controls. Behavior in the Morris water maze was assessed on days 11-14 following injury. Stimulated LFP animals showed significantly shorter latencies to find the hidden platform than did controls. Despite these behavioral effects, neurohistological examination did not reveal significant differences in lesion extent, density of fluorojade positive neurons, reactive astrocytes or numbers of spared neurons in the CA3 subarea

  6. Vagus nerve stimulation mediates protection from kidney ischemia-reperfusion injury through α7nAChR+ splenocytes

    PubMed Central

    Inoue, Tsuyoshi; Abe, Chikara; Sung, Sun-sang J.; Moscalu, Stefan; Jankowski, Jakub; Huang, Liping; Ye, Hong; Guyenet, Patrice G.

    2016-01-01

    The nervous and immune systems interact in complex ways to maintain homeostasis and respond to stress or injury, and rapid nerve conduction can provide instantaneous input for modulating inflammation. The inflammatory reflex referred to as the cholinergic antiinflammatory pathway regulates innate and adaptive immunity, and modulation of this reflex by vagus nerve stimulation (VNS) is effective in various inflammatory disease models, such as rheumatoid arthritis and inflammatory bowel disease. Effectiveness of VNS in these models necessitates the integration of neural signals and α7 nicotinic acetylcholine receptors (α7nAChRs) on splenic macrophages. Here, we sought to determine whether electrical stimulation of the vagus nerve attenuates kidney ischemia-reperfusion injury (IRI), which promotes the release of proinflammatory molecules. Stimulation of vagal afferents or efferents in mice 24 hours before IRI markedly attenuated acute kidney injury (AKI) and decreased plasma TNF. Furthermore, this protection was abolished in animals in which splenectomy was performed 7 days before VNS and IRI. In mice lacking α7nAChR, prior VNS did not prevent IRI. Conversely, adoptive transfer of VNS-conditioned α7nAChR splenocytes conferred protection to recipient mice subjected to IRI. Together, these results demonstrate that VNS-mediated attenuation of AKI and systemic inflammation depends on α7nAChR-positive splenocytes. PMID:27088805

  7. Influence of different frequencies of transcutaneous electrical nerve stimulation on the threshold and pain intensity in young subjects

    PubMed Central

    Gomes, Adriana de Oliveira; Silvestre, Ana Caroline; da Silva, Cristina Ferreira; Gomes, Mariany Ribeiro; Bonfleur, Maria Lúcia; Bertolini, Gladson Ricardo Flor

    2014-01-01

    Objective To investigate the effects of different transcutaneous electrical nerve stimulation frequencies in nociception front of a pressure pain threshold and cold in healthy individuals. Methods Twenty healthy subjects were divided into four groups, all of which have gone through all forms of electrical stimulation at different weeks. Assessments were pre and post-therapy, 20 and 60 minutes after stimulation. To evaluate the pressure pain threshold, an algometer was used with one tapered tip, pressing the hypothenar region until voluntary report the word “pain”. Cold pain intensity was assessed by immersion in water at 5°C for 30 seconds; at the end, the subject was asked to quantify the pain intensity on a Visual Analog Scale for Pain. For electrical stimulation, two electrodes were used near the elbow, for 20 minutes, with an intensity strong, but not painful. The frequency was in accordance with the group: 0Hz (placebo); 7Hz; 100Hz; and 255Hz. Results Both for the assessment of pressure pain threshold as the cold pain intensity, there was no significant difference (p>0.05). Conclusion We conclude that the use of transcutaneous electrical nerve stimulation on dermatomes C6 to C8 produced no significant change in pressure pain threshold or cold discomfort. PMID:25295453

  8. Frequency-dependent interference by magnetic fields of nerve growth factor-induced neurite outgrowth in PC-12 cells

    SciTech Connect

    Blackman, C.F.; Benane, S.G.; House, D.E.

    1995-12-31

    The authors have shown that 50 Hz sinusoidal magnetic fields within the 5--10 microTesla ({micro}T) rms range cause an intensity-dependent reduction in nerve growth factor (NGF) stimulation of neurite outgrowth (NO) in PC12- cells. Here they report on the frequency dependence of this response over the 15--70 Hz range at 5 Hz intervals. Primed PC-12 cells were plated in collagen-coated, 60 mm plastic petri dishes with or without 5 ng/ml NGF and were exposed to sinusoidal magnetic fields for 22 h in a CO{sub 2} incubator at 37 C. One 1,000-turn coil, 20 cm in diameter, generated vertically oriented magnetic fields. The dishes were stacked on the center axis of the coil to provide a range of intensities between 3.5 and 9.0 {micro}T rms. The flux density of the ambient DC magnetic field was 37 {micro}T vertical and 29 {micro}T horizontal. The assay consisted of counting over 100 cells in the central portion (radius {le}0.3 cm) of each dish and scoring cells positive for NO. Sham exposure of cells treated identically with NGF demonstrated no difference in the percentage of cells with NO between exposed and magnetically shielded locations within the incubator. Analysis of variance demonstrated flux density-dependent reductions in NGF-stimulated NO over the 35--70 Hz frequency range, whereas frequencies between 15 Hz and 30 Hz produced no obvious reduction. The results also demonstrated a relative maximal sensitivity of cells at 40 Hz with a possible additional sensitivity region at or above 70 Hz. These findings suggest a biological influence of perpendicular AC/DC magnetic fields different from those identified by the ion parametric resonance model, which uses strictly parallel AC/DC fields.

  9. Identification of Stimulated Sites Using Artificial Neural Networks Based on Transcranial Magnetic Stimulation-Elicited Motor Evoked Potentials and Finger Forces

    NASA Astrophysics Data System (ADS)

    Fukuda, Hiroshi; Odagaki, Masato; Hiwaki, Osamu

    Motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) over the primary motor cortex (M1) vary in their amplitude from trial to trial. To investigate the functions of motor cortex by TMS, it is necessary to confirm the causal relationship between stimulated sites and variable MEPs. We created artificial neural networks to classify sets of variable MEP signals and finger forces into the corresponding stimulated sites. We conducted TMS at three different positions over M1 and measured MEPs of hand and forearm muscles and forces of the index finger in four subjects. We estimated the sites within motor cortex stimulated by TMS based on cortical columnar structure and nerve excitation properties. Finally, we tried to classify the various MEPs and finger forces into three groups using artificial neural networks. MEPs and finger forces varied from trial to trial, even if the stimulating coil was fixed on the subject's head. Our proposed neural network was able to identify the MEPs and finger forces with the corresponding stimulated sites in M1. We proposed the artificial neural networks to confirm the TMS-stimulated sites using various MEPs and evoked finger forces.

  10. Use of Transcranial Magnetic Stimulation in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Oberman, Lindsay M.; Rotenberg, Alexander; Pascual-Leone, Alvaro

    2015-01-01

    The clinical, social and financial burden of autism spectrum disorder (ASD) is staggering. We urgently need valid and reliable biomarkers for diagnosis and effective treatments targeting the often debilitating symptoms. Transcranial magnetic stimulation (TMS) is beginning to be used by a number of centers worldwide and may represent a novel…

  11. Transcranial magnetic stimulation (TMS) in Attention Deficit Hyperactivity Disorder (ADHD).

    PubMed

    Zaman, Rashid

    2015-09-01

    Attention Deficit Hyperactivity Disorder (ADHD) is a common neuropsychiatric disorder, which affects children as well as adults and leads to significant impairment in educational, social and occupational functioning and has associated personal and societal costs. Whilst there are effective medications (mostly stimulants) as well as some psychobehavioural treatments that help alleviate symptoms of ADHD, there is still need to improve our understanding of its neurobiology as well as explore other treatment options. Transcranial Magnetic Stimulation (TMS) and repetitive transcranial magnetic stimulation (rTMS) are safe and non-invasive investigative and therapeutic tools respectively. In this short article, I will explore their potential for improving our understanding of the neurobiology of ADHD as well consider its as a possible treatment option.

  12. [Fundamentals and Clinical Applications of Transcranial Magnetic Stimulation in Neuropsychiatry].

    PubMed

    Malavera, Mayra; Silva, Federico; García, Ronald; Rueda, Ligia; Carrillo, Sandra

    2014-03-01

    Transcranial Magnetic Stimulation (TMS) is a non-invasive method for stimulation of brain that is based on the ability of a generated magnetic field to penetrate skull and brain meninges, inducing an electric current in the brain tissues that produces neuronal depolarization. TMS can be applied as single pulse of stimulation, pairs of stimuli separated by variable intervals to the same or different brain areas, or as trains of repetitive stimuli at various frequencies. Its mechanism of action is currently unknown. Repetitive TMS can modify the excitability of the cerebral cortex, and has been postulated as a diagnostic and therapeutic tool in the area of neuropsychiatry. The aim of this article is to review the knowledge of the TMS as regards its basic principles, pathophysiological mechanism, and its usefulness in clinical practice.

  13. Transcranial magnetic stimulation (TMS) in Attention Deficit Hyperactivity Disorder (ADHD).

    PubMed

    Zaman, Rashid

    2015-09-01

    Attention Deficit Hyperactivity Disorder (ADHD) is a common neuropsychiatric disorder, which affects children as well as adults and leads to significant impairment in educational, social and occupational functioning and has associated personal and societal costs. Whilst there are effective medications (mostly stimulants) as well as some psychobehavioural treatments that help alleviate symptoms of ADHD, there is still need to improve our understanding of its neurobiology as well as explore other treatment options. Transcranial Magnetic Stimulation (TMS) and repetitive transcranial magnetic stimulation (rTMS) are safe and non-invasive investigative and therapeutic tools respectively. In this short article, I will explore their potential for improving our understanding of the neurobiology of ADHD as well consider its as a possible treatment option. PMID:26417832

  14. Cognitive Impairment After Sleep Deprivation Rescued by Transcranial Magnetic Stimulation Application in Octodon degus.

    PubMed

    Estrada, C; López, D; Conesa, A; Fernández-Gómez, F J; Gonzalez-Cuello, A; Toledo, F; Tunez, I; Blin, O; Bordet, R; Richardson, J C; Fernandez-Villalba, E; Herrero, M T

    2015-11-01

    Sleep is indispensable for maintaining regular daily life activities and is of fundamental physiological importance for cognitive performance. Sleep deprivation (SD) may affect learning capacity and the ability to form new memories, particularly with regard to hippocampus-dependent tasks. Transcranial magnetic stimulation (TMS) is a non-invasive procedure of electromagnetic induction that generates electric currents, activating nearby nerve cells in the stimulated cortical area. Several studies have looked into the potential therapeutic use of TMS. The present study was designed to evaluate how TMS could improve learning and memory functions following SD in Octodon degus. Thirty juvenile (18 months old) females were divided into three groups (control, acute, and chronic TMS treatment-with and without SD). TMS-treated groups were placed in plastic cylindrical cages designed to keep them immobile, while receiving head magnetic stimulation. SD was achieved by gently handling the animals to keep them awake during the night. Behavioral tests included radial arm maze (RAM), Barnes maze (BM), and novel object recognition. When TMS treatment was applied over several days, there was significant improvement of cognitive performance after SD, with no side effects. A single TMS session reduced the number of errors for the RAM test and improved latency and reduced errors for the BM test, which both evaluate spatial memory. Moreover, chronic TMS treatment brings about a significant improvement in both spatial and working memories. PMID:26194615

  15. Cognitive Impairment After Sleep Deprivation Rescued by Transcranial Magnetic Stimulation Application in Octodon degus.

    PubMed

    Estrada, C; López, D; Conesa, A; Fernández-Gómez, F J; Gonzalez-Cuello, A; Toledo, F; Tunez, I; Blin, O; Bordet, R; Richardson, J C; Fernandez-Villalba, E; Herrero, M T

    2015-11-01

    Sleep is indispensable for maintaining regular daily life activities and is of fundamental physiological importance for cognitive performance. Sleep deprivation (SD) may affect learning capacity and the ability to form new memories, particularly with regard to hippocampus-dependent tasks. Transcranial magnetic stimulation (TMS) is a non-invasive procedure of electromagnetic induction that generates electric currents, activating nearby nerve cells in the stimulated cortical area. Several studies have looked into the potential therapeutic use of TMS. The present study was designed to evaluate how TMS could improve learning and memory functions following SD in Octodon degus. Thirty juvenile (18 months old) females were divided into three groups (control, acute, and chronic TMS treatment-with and without SD). TMS-treated groups were placed in plastic cylindrical cages designed to keep them immobile, while receiving head magnetic stimulation. SD was achieved by gently handling the animals to keep them awake during the night. Behavioral tests included radial arm maze (RAM), Barnes maze (BM), and novel object recognition. When TMS treatment was applied over several days, there was significant improvement of cognitive performance after SD, with no side effects. A single TMS session reduced the number of errors for the RAM test and improved latency and reduced errors for the BM test, which both evaluate spatial memory. Moreover, chronic TMS treatment brings about a significant improvement in both spatial and working memories.

  16. Activation and suppression of the trapezius muscle induced by transcranial magnetic stimulation.

    PubMed

    Strenge, H; Jahns, R

    1998-01-01

    Motor evoked potentials (MEPs) and silent periods (SPs) in the trapezius muscle induced by transcranial magnetic stimulation (TMS) were investigated in 15 healthy subjects. Stimuli were applied with a Novametrix Magnetic stimulator using a 14 cm circular coil 4 cm lateral to the vertex on the biauricular line. Surface electrodes were used for simultaneous bilateral electromyographic recordings of the trapezius. TMS invariably induced contralateral MEPs (latency 10.5 +/- 1.3 ms, mean +/- SD), with ipsilateral responses in 53% of the subjects (latency 11.1 +/- 2.5 ms). The mean duration of the SPs was approximately 90 ms on both sides. There were no significant side differences between any of the MEP or SP parameters. To study the influence of subcortical inhibition phenomena TMS induced responses were assessed following electrical mental nerve stimulation with interstimulus intervals (ISI) of 0-100 ms. MEP latencies significantly increased at ISI of 10-100 ms, whereas MEP amplitudes and SPs did not change. These findings may reflect a trigeminal induced exteroceptive suppression of trapezius muscle activity. PMID:9637939

  17. Corticospinal potentials after electrical and magnetic stimulation in man.

    PubMed

    Berardelli, A; Inghilleri, M; Cruccu, G; Manfredi, M

    1991-01-01

    The present report deals with our study of the descending volley evoked by both electrical and magnetic transcranial stimulation in man. We discuss the differences of these two techniques specifically as regards the latency and amplitude of evoked potentials. In both cases, electrodes were placed either in the epidural space or directly on the spinal cord. Following electrical stimulation, the descending volley consisted of an early wave which appeared at low stimulation intensity and increased in amplitude and decreased in latency when the strength of the stimulus was increased. At high stimulation intensities the early wave was followed by later waves which travel at the same speed as the initial wave. By delivering paired cortical stimuli, the early wave evoked by the test stimuli is present at 1-msec interval and progressively recovered with longer intervals. The recovery cycle of the later waves is also extremely short. Following magnetic stimulation, the descending volley also consisted of an initial wave followed by later waves. The initial wave has a slightly longer latency, a higher threshold and a smaller amplitude than the early wave evoked by electrical stimulation. The results are discussed with reference to the D and I waves recorded from the pyramidal tract in animals.

  18. Incidence of hemidiaphragmatic paresis after peripheral nerve stimulator versus ultrasound guided interscalene brachial plexus block

    PubMed Central

    Ghodki, Poonam Sachin; Singh, Noopur Dasmit

    2016-01-01

    Background and Aims: We compared interscalene brachial plexus block (ISBPB) using peripheral nerve stimulation (PNS) and ultrasound (US) techniques. The primary outcomes were the incidence of hemidiaphragmatic paresis (HDP) and the duration of the block. Secondary outcomes were the block success rate, time to conduct the block, onset of sensory block, and dermatomal spread, postoperative pain by Numeric Rating Scale (NRS), duration of postoperative analgesia and incidence of complications. Material and Methods: We conducted a prospective, randomized, and observer-blinded study in 60 patients undergoing shoulder arthroscopy under block plus general anesthesia. ISBPB was performed with 10 ml of 0.5% bupivacaine using either PNS (Group PNS, n = 30) or US (Group US, n = 30). Hemidiaphragmatic function, the primary outcome, was assessed by ultrasonographic evaluation of diaphragmatic movement and pulmonary function tests using a bedside spirometer (forced vital capacity, forced expiratory volume in 1 s and peak expiratory flow rate). General anesthesia was administered to all the patients for surgery. P < 0.05 test was considered to be statistically significant. Results: Twelve patients in Group PNS had HDP and none in Group US (P < 0.0001). PFTs were also significantly reduced in Group PNS (P < 0.0001). The time to conduct the block and sensory onset time both were less in Group US (P < 0.05). The groups did not differ in block success rate, duration of analgesia, and NRS. Other complications like incidence of Horner's syndrome and vascular puncture were comparable in both the groups. Conclusions: PNS guided ISBPB with 10 ml of 0.5% bupivacaine is associated with a higher incidence of HDP as compared to US guided ISBPB. There is no significant difference in quality or duration of analgesia in the two groups. PMID:27275045

  19. The antidepressant-like effect of vagus nerve stimulation is mediated through the locus coeruleus.

    PubMed

    Grimonprez, Annelies; Raedt, Robrecht; Portelli, Jeanelle; Dauwe, Ine; Larsen, Lars Emil; Bouckaert, Charlotte; Delbeke, Jean; Carrette, Evelien; Meurs, Alfred; De Herdt, Veerle; Boon, Paul; Vonck, Kristl

    2015-09-01

    It has been shown that vagus nerve stimulation (VNS) has an antidepressant-like effect in the forced swim test. The mechanism of action underlying this effect is incompletely understood, but there is evidence suggesting that the locus coeruleus (LC) may play an important role. In this study, noradrenergic LC neurons were selectively lesioned to test their involvement in the antidepressant-like effect of VNS in the forced swim test. Forced swim test behavior was assessed in rats that were subjected to VNS or sham treatment. In half of the VNS-treated animals, the noradrenergic neurons from the LC were lesioned using the selective neurotoxin DSP-4 [N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride], yielding three experimental arms: sham, VNS and DSP-4-VNS (n = 8 per group). Furthermore, the open field test was performed to evaluate locomotor activity. A dopamine-β-hydroxylase immunostaining was performed to confirm lesioning of noradrenergic LC neurons. VNS significantly reduced the percentage of immobility time in the forced swim test compared to sham treatment (median: 56%, interquartile range: 41% vs. median: 75%, interquartile range: 12%). This antidepressant-like effect of VNS could not be demonstrated in the DSP-4-VNS group (median: 79%, interquartile range: 33%). Locomotor activity in the open field test was not different between the three treatment arms. The absence of hippocampal dopamine-β-hydroxylase immunostaining in the DSP-4-treated rats confirmed the lesioning of noradrenergic neurons originating from the brainstem LC. The results of this study demonstrate that the noradrenergic neurons from the LC play an important role in the antidepressant-like effect of VNS.

  20. Evidence-Based Guideline Update: Vagus Nerve Stimulation for the Treatment of Epilepsy

    PubMed Central

    Morris, George L.; Gloss, David; Buchhalter, Jeffrey; Mack, Kenneth J.; Nickels, Katherine; Harden, Cynthia

    2013-01-01

    OBJECTIVE: To evaluate the evidence since the 1999 assessment regarding efficacy and safety of vagus nerve stimulation (VNS) for epilepsy, currently approved as adjunctive therapy for partial-onset seizures in patients >12 years. METHODS: We reviewed the literature and identified relevant published studies. We classified these studies according to the American Academy of Neurology evidence-based methodology. RESULTS: VNS is associated with a >50% seizure reduction in 55% (95% confidence interval [CI] 50%–59%) of 470 children with partial or generalized epilepsy (13 Class III studies). VNS is associated with a >50% seizure reduction in 55% (95% CI 46%–64%) of 113 patients with Lennox-Gastaut syndrome (LGS) (4 Class III studies). VNS is associated with an increase in ≥50% seizure frequency reduction rates of ~7% from 1 to 5 years postim-plantation (2 Class III studies). VNS is associated with a significant improvement in standard mood scales in 31 adults with epilepsy (2 Class III studies). Infection risk at the VNS implantation site in children is increased relative to that in adults (odds ratio 3.4, 95% CI 1.0–11.2). VNS is possibly effective for seizures (both partial and generalized) in children, for LGS-associated seizures, and for mood problems in adults with epilepsy. VNS may have improved efficacy over time. RECOMMENDATIONS: VNS may be considered for seizures in children, for LGS-associated seizures, and for improving mood in adults with epilepsy (Level C). VNS may be considered to have improved efficacy over time (Level C). Children should be carefully monitored for site infection after VNS implantation. Neurology® 2013;81:1–7 PMID:24348133

  1. Evidence-based guideline update: Vagus nerve stimulation for the treatment of epilepsy

    PubMed Central

    Morris, George L.; Gloss, David; Buchhalter, Jeffrey; Mack, Kenneth J.; Nickels, Katherine; Harden, Cynthia

    2013-01-01

    Objective: To evaluate the evidence since the 1999 assessment regarding efficacy and safety of vagus nerve stimulation (VNS) for epilepsy, currently approved as adjunctive therapy for partial-onset seizures in patients >12 years. Methods: We reviewed the literature and identified relevant published studies. We classified these studies according to the American Academy of Neurology evidence-based methodology. Results: VNS is associated with a >50% seizure reduction in 55% (95% confidence interval [CI] 50%–59%) of 470 children with partial or generalized epilepsy (13 Class III studies). VNS is associated with a >50% seizure reduction in 55% (95% CI 46%–64%) of 113 patients with Lennox-Gastaut syndrome (LGS) (4 Class III studies). VNS is associated with an increase in ≥50% seizure frequency reduction rates of ∼7% from 1 to 5 years postimplantation (2 Class III studies). VNS is associated with a significant improvement in standard mood scales in 31 adults with epilepsy (2 Class III studies). Infection risk at the VNS implantation site in children is increased relative to that in adults (odds ratio 3.4, 95% CI 1.0–11.2). VNS is possibly effective for seizures (both partial and generalized) in children, for LGS-associated seizures, and for mood problems in adults with epilepsy. VNS may have improved efficacy over time. Recommendations: VNS may be considered for seizures in children, for LGS-associated seizures, and for improving mood in adults with epilepsy (Level C). VNS may be considered to have improved efficacy over time (Level C). Children should be carefully monitored for site infection after VNS implantation. PMID:23986299

  2. Randomized Controlled Trial of Surface Peroneal Nerve Stimulation for Motor Relearning in Lower Limb Hemiparesis

    PubMed Central

    Taylor, Paul N.; Gunzler, Douglas D.; Buurke, Jaap H.; IJzerman, Maarten J.; Chae, John

    2013-01-01

    Objective To compare the motor relearning effect of a surface peroneal nerve stimulator (PNS) versus usual care on lower limb motor impairment, activity limitation, and quality of life among chronic stroke survivors. Design Single-blinded randomized controlled trial Setting Teaching hospital of academic medical center Participants 110 chronic stroke survivors (> 12-wks post-stroke) with unilateral hemiparesis and dorsiflexion strength of ≤ 4/5 on the Medical Research Council scale Interventions Subjects were stratified by motor impairment level and then randomized to ambulation training with either a surface PNS device or usual care (ankle foot orthosis or no device) intervention. Subjects were treated for 12-wks and followed for 6-months post-treatment. Main Outcome Measures Lower limb portion of the Fugl-Meyer (FM) Assessment (motor impairment), the Modified Emory Functional Ambulation Profile (mEFAP) performed without a device (functional ambulation), and the Stroke Specific Quality of Life (SSQOL) scale. Results There was no significant treatment group main effect or treatment group by time interaction effect on FM, mEFAP, or SSQOL raw scores (p>0.05). The time effect was significant for the three raw scores (p<0.05). However, when comparing average change scores from baseline (T1) to end of treatment, (T2, 12-wks), and at 12-wks (T3) and 24-wks (T4) after end of treatment, significant differences were noted only for the mEFAP and SSQOL scores. The change in the average scores for both mEFAP and SSQOL occurred between T1 and T2, followed by relative stability thereafter. Conclusions There was no evidence of a motor relearning effect on lower limb motor impairment in either the PNS or usual care groups. However, both PNS and usual care groups demonstrated significant improvements in functional mobility and quality of life during the treatment period, which were maintained at 6-months follow-up. PMID:23399456

  3. Characterization of evoked tactile sensation in forearm amputees with transcutaneous electrical nerve stimulation

    NASA Astrophysics Data System (ADS)

    Chai, Guohong; Sui, Xiaohong; Li, Si; He, Longwen; Lan, Ning

    2015-12-01

    Objective. The goal of this study is to characterize the phenomenon of evoked tactile sensation (ETS) on the stump skin of forearm amputees using transcutaneous electrical nerve stimulation (TENS). Approach. We identified the projected finger map (PFM) of ETS on the stump skin in 11 forearm amputees, and compared perceptual attributes of the ETS in nine forearm amputees and eight able-bodied subjects using TENS. The profile of perceptual thresholds at the most sensitive points (MSPs) in each finger-projected area was obtained by modulating current amplitude, pulse width, and frequency of the biphasic, rectangular current stimulus. The long-term stability of the PFM and the perceptual threshold of the ETS were monitored in five forearm amputees for a period of 11 months. Main results. Five finger-specific projection areas can be independently identified on the stump skin of forearm amputees with a relatively long residual stump length. The shape of the PFM was progressively similar to that of the hand with more distal amputation. Similar sensory modalities of touch, pressure, buzz, vibration, and numb below pain sensation could be evoked both in the PFM of the stump skin of amputees and in the normal skin of able-bodied subjects. Sensory thresholds in the normal skin of able-bodied subjects were generally lower than those in the stump skin of forearm amputees, however, both were linearly modulated by current amplitude and pulse width. The variation of the MSPs in the PFM was confined to a small elliptical area with 95% confidence. The perceptual thresholds of thumb-projected areas were found to vary less than 0.99 × 10-2 mA cm-2. Significance. The stable PFM and sensory thresholds of ETS are desirable for a non-invasive neural interface that can feed back finger-specific tactile information from the prosthetic hand to forearm amputees.

  4. Cortical edema in moderate fluid percussion brain injury is attenuated by vagus nerve stimulation.

    PubMed

    Clough, R W; Neese, S L; Sherill, L K; Tan, A A; Duke, A; Roosevelt, R W; Browning, R A; Smith, D C

    2007-06-29

    Development of cerebral edema (intracellular and/or extracellular water accumulation) following traumatic brain injury contributes to mortality and morbidity that accompanies brain injury. Chronic intermittent vagus nerve stimulation (VNS) initiated at either 2 h or 24 h (VNS: 30 s train of 0.5 mA, 20 Hz, biphasic pulses every 30 min) following traumatic brain injury enhances recovery of motor and cognitive function in rats in the weeks following brain injury; however, the mechanisms of facilitated recovery are unknown. The present study examines the effects of VNS on development of acute cerebral edema following unilateral fluid percussion brain injury (FPI) in rats, concomitant with assessment of their behavioral recovery. Two hours following FPI, VNS was initiated. Behavioral testing, using both beam walk and locomotor placing tasks, was conducted at 1 and 2 days following FPI. Edema was measured 48 h post-FPI by the customary method of region-specific brain weights before and after complete dehydration. Results of this study replicated that VNS initiated at 2 h after FPI: 1) effectively facilitated the recovery of vestibulomotor function at 2 days after FPI assessed by beam walk performance (P<0.01); and 2) tended to improve locomotor placing performance at the same time point (P=0.18). Most interestingly, results of this study showed that development of edema within the cerebral cortex ipsilateral to FPI was significantly attenuated at 48 h in FPI rats receiving VNS compared with non-VNS FPI rats (P<0.04). Finally, a correlation analysis between beam walk performance and cerebral edema following FPI revealed a significant inverse correlation between behavior performance and cerebral edema. Together, these results suggest that VNS facilitation of motor recovery following experimental brain injury in rats is associated with VNS-mediated attenuation of cerebral edema. PMID:17543463

  5. Transcutaneous Electrical Nerve Stimulation and Conditioned Pain Modulation Influence the Perception of Pain in Humans

    PubMed Central

    Liebano, Richard E.; Vance, Carol G.T.; Rakel, Barbara; Lee, Jennifer E.; Cooper, Nicholas A.; Marchand, Serge; Walsh, Deirdre M.; Sluka, Kathleen A.

    2013-01-01

    Background Research in animal models suggest that transcutaneous electrical nerve stimulation (TENS) and conditioned pain modulation (CPM) produce analgesia via two different supraspinal pathways. No known studies have examined whether TENS and CPM applied simultaneously in human subjects will enhance the analgesic effect of either treatment alone. The purpose of the current study was to investigate whether the simultaneous application of TENS and CPM will enhance the analgesic effect of that produced by either treatment alone. Methods Sixty healthy adults were randomly allocated into 2 groups: 1) CPM plus Active TENS; 2) CPM plus Placebo TENS. Pain threshold for heat (HPT) and pressure (PPT) was recorded from subject’s left forearm at baseline, during CPM, during Active or Placebo TENS, and during CPM plus Active or Placebo TENS. CPM was induced by placing the subjects’ contralateral arm in a hot water bath (46.5°C) for two minutes. TENS (100µs, 100Hz) was applied to the forearm for 20 minutes at a strong but comfortable intensity. Results Active TENS alone increased PPT (but not HPT) more than Placebo TENS alone (p=0.011). Combining CPM and Active TENS did not significantly increase PPT (p=0.232) or HPT (p=0.423) beyond CPM plus Placebo TENS. There was a significant positive association between PPT during CPM and during Active TENS (r2=0.46, p=0.003). Conclusions TENS application increases PPT, however combining CPM and TENS does not increase the CPM’s hypoalgesic response. CPM effect on PPT is associated with effects of TENS on PPT. PMID:23650092

  6. Sensory nerves contribute to cutaneous vasodilator response to cathodal stimulation in healthy rats.

    PubMed

    Gohin, Stéphanie; Decorps, Johanna; Sigaudo-Roussel, Dominique; Fromy, Bérengère

    2015-09-01

    Cutaneous current-induced vasodilation (CIV) in response to galvanic current application is an integrative model of neurovascular interaction that relies on capsaicin-sensitive fiber activation. The upstream and downstream mechanisms related to the activation of the capsaicin-sensitive fibers involved in CIV are not elucidated. In particular, the activation of cutaneous transient receptor potential vanilloid type-1 (TRPV1) channels and/or acid-sensing ion channels (ASIC) (activators mechanisms) and the release of calcitonin gene-related peptide (CGRP) and substance P (SP) (effector mechanisms) have been tested. To assess cathodal CIV, we measured cutaneous blood flow using laser Doppler flowmetry for 20min following cathodal current application (240s, 100μA) on the skin of the thigh in anesthetized healthy rats for 20min. CIV was studied in rats treated with capsazepine and amiloride to inhibit TRPV1 and ASIC channels, respectively; CGRP8-37 and SR140333 to antagonize CGRP and neurokinin-1 (NK1) receptors, respectively; compared to their respective controls. Cathodal CIV was attenuated by capsazepine (12±2% vs 54±6%, P<0.001), amiloride (19±8% vs 61±6%, P<0.01), CGRP8-37 (15±6% vs 61±6%, P<0.001) and SR140333 (9±5% vs 54±6%, P<0.001) without changing local acidification. This is the first integrative study performed in healthy rats showing that cutaneous vasodilation in response to cathodal stimulation is initiated by activation of cutaneous TRPV1 and ASIC channels likely through local acidification. The involvement of CGRP and NK1 receptors suggests that cathodal CIV is the result of CGRP and SP released through activated capsaicin-sensitive fibers. Therefore cathodal CIV could be a valuable method to assess sensory neurovascular function in the skin, which would be particularly relevant to evaluate the presence of small nerve fiber disorders and the effectiveness of treatments.

  7. Effect of selective vagal nerve stimulation on blood pressure, heart rate and respiratory rate in rats under metoprolol medication.

    PubMed

    Gierthmuehlen, Mortimer; Plachta, Dennis T T

    2016-02-01

    Selective vagal nerve stimulation (sVNS) has been shown to reduce blood pressure without major side effects in rats. This technology might be the key to non-medical antihypertensive treatment in patients with therapy-resistant hypertension. β-blockers are the first-line therapy of hypertension and have in general a bradycardic effect. As VNS itself can also promote bradycardia, it was the aim of this study to investigate the influence of the β1-selective blocker Metoprolol on the effect of sVNS especially with respect to the heart rate. In 10 male Wistar rats, a polyimide multichannel-cuff electrode was placed around the vagal nerve bundle to selectively stimulate the aortic depressor nerve fibers. The stimulation parameters were adapted to the thresholds of individual animals and were in the following ranges: frequency 30-50 Hz, amplitude 0.3-1.8 mA and pulse width 0.3-1.3 ms. Blood pressure responses were detected with a microtip transducer in the carotid artery, and electrocardiography was recorded with s.c. chest electrodes. After IV administration of Metoprolol (2 mg kg(-1) body weight), the animals' mean arterial blood pressure (MAP) and heart rate (HR) decreased significantly. Although the selective electrical stimulation of the baroreceptive fibers reduced MAP and HR, both effects were significantly alleviated by Metoprolol. As a side effect, the rate of stimulation-induced apnea significantly increased after Metoprolol administration. sVNS can lower the MAP under Metoprolol without causing severe bradycardia.

  8. Estimating nerve excitation thresholds to cutaneous electrical stimulation by finite element modeling combined with a stochastic branching nerve fiber model.

    PubMed

    Mørch, Carsten Dahl; Hennings, Kristian; Andersen, Ole Kæseler

    2011-04-01

    Electrical stimulation of cutaneous tissue through surface electrodes is an often used method for evoking experimental pain. However, at painful intensities both non-nociceptive Aβ-fibers and nociceptive Aδ- and C-fibers may be activated by the electrical stimulation. This study proposes a finite element (FE) model of the extracellular potential and stochastic branching fiber model of the afferent fiber excitation thresholds. The FE model described four horizontal layers; stratum corneum, epidermis, dermis, and hypodermal used to estimate the excitation threshold of Aβ-fibers terminating in dermis and Aδ-fibers terminating in epidermis. The perception thresholds of 11 electrodes with diameters ranging from 0.2 to 20 mm were modeled and assessed on the volar forearm of healthy human volunteers by an adaptive two-alternative forced choice algorithm. The model showed that the magnitude of the current density was highest for smaller electrodes and decreased through the skin. The excitation thresholds of the Aδ-fibers were lower than the excitation thresholds of Aβ-fibers when current was applied through small, but not large electrodes. The experimentally assessed perception threshold followed the lowest excitation threshold of the modeled fibers. The model confirms that preferential excitation of Aδ-fibers may be achieved by small electrode stimulation due to higher current density in the dermoepidermal junction. PMID:21207174

  9. Identifying a Safe Range of Stimulation Current for Intraoperative Neuromonitoring of the Recurrent Laryngeal Nerve: Results from a Canine Model

    PubMed Central

    Li, Tao; Zhou, Gang; Yang, Yang; Gao, Zhi-Dong; Guo, Peng; Shen, Zhan-Long; Yang, Xiao-Dong; Xie, Qi-Wei; Ye, Ying-Jiang; Jiang, Ke-Wei; Wang, Shan

    2016-01-01

    Background: Intraoperative neuromonitoring (IONM) of the recurrent laryngeal nerve (RLN) has been widely applied during thyroid surgery. However, the safe range of stimulation intensity for IONM remains undetermined. Methods: Total thyroidectomies were performed on twenty dogs, and their RLNs were stimulated with a current of 5–20 mA (step-wise in 5 mA increments) for 1 min. The evoked electromyography (EMG) of vocal muscles before and after supramaximal stimulation were recorded and compared. Acute microstructural morphological changes in the RLNs were observed immediately postoperatively under an electron microscope. Results: The average stimulating threshold for RLNs stimulated with 15 mA and 20 mA showed no significant changes compared to the unstimulated RLNs (15 mA group: 0.320 ± 0.123 mA vs. 0.315 ± 0.097 mA, P = 0.847; 20 mA group: 0.305 ± 0.101 mA vs. 0.300 ± 0.103 mA, P = 0.758). Similar outcomes were shown in average evoked EMG amplitude (15 mA group: 1,026 ± 268 μV vs. 1,021 ± 273 μV, P = 0.834; 20 mA group: 1,162 ± 275 μV vs. 1,200 ± 258 μV, P = 0.148). However, obvious acute microstructural morphological changes were observed in the nerves that were stimulated with 20 mA. Conclusions: A stimulation intensity less than 15 mA might be safe for IONM of the RLN. PMID:27453233

  10. Quasi-trapezoidal pulses to selectively block the activation of intrinsic laryngeal muscles during vagal nerve stimulation

    NASA Astrophysics Data System (ADS)

    Tosato, M.; Yoshida, K.; Toft, E.; Struijk, J. J.

    2007-09-01

    The stimulation of the vagus nerve has been used as an anti-epileptic treatment for over a decade, and its use for depression and chronic heart failure is currently under investigation. Co-activation of the intrinsic laryngeal muscles may limit the clinical use of vagal stimulation, especially in the case of prolonged activation. To prevent this, the use of a selective stimulation paradigm has been tested in seven acute pig experiments. Quasi-trapezoidal pulses successfully blocked the population of the largest and fastest vagal myelinated fibers being responsible for the co-activation. The first response in the vagus compound action potential was reduced by 75 ± 22% (mean ± SD) and the co-activated muscle action potential by 67 ± 25%. The vagal bradycardic effects remained unchanged during the selective block, confirming the leading role of thin nerve fibers for the vagal control of the heart. Quasi-trapezoidal pulses may be an alternative to rectangular pulses in clinical vagal stimulation when the co-activation of laryngeal muscles must be avoided.

  11. Effects of sympathetic nerve stimulation on membrane potential, [Ca2+]i and force in the arrested sinus venosus of the toad, Bufo marinus.

    PubMed Central

    Cousins, H M; Bramich, N J

    1997-01-01

    1. The effects of sympathetic nerve stimulation on membrane potential and on the intracellular concentration of calcium ions, [Ca2+]i, were recorded concurrently from the sinus venosus of the toad, Bufo marinus, in preparations where beating had been abolished by adding an organic calcium antagonist to the physiological saline. In a separate set of experiments the effects of sympathetic nerve stimulation on force production were examined. 2. Stimulation of the sympathetic nerves caused a membrane depolarization and a simultaneous increase in [Ca2+]i. Both responses were reduced by dihydroergotamine (20 microM). 3. The membrane depolarization and increase in [Ca2+]i evoked by sympathetic nerve stimulation were abolished by ryanodine (10 microM), or caffeine (3 mM). The effects of caffeine, but not those of ryanodine, were fully reversible. 4. Although the Ca(2+)-ATPase inhibitor thapsigargin (30 microM) itself had little effect on the responses to sympathetic nerve stimulation, in its presence caffeine (3 mM) irreversibly abolished the responses. 5. In the presence of nifedipine (10 microM), sympathetic nerve stimulation caused contractions of the sinus venosus. These responses were abolished by either ryanodine (10 microM) or caffeine (3 mM). 6. The results suggest that neuronally released transmitter activates a complex biochemical pathway which triggers the release of Ca2+ from internal stores. PMID:9423190

  12. Short-term effect of electrical nerve stimulation on spinal reciprocal inhibition during robot-assisted passive stepping in humans.

    PubMed

    Obata, Hiroki; Ogawa, Tetsuya; Kitamura, Taku; Masugi, Yohei; Takahashi, Miho; Kawashima, Noritaka; Nakazawa, Kimitaka

    2015-09-01

    The purpose of this study was to investigate the effect of electrical stimulation to the common peroneal nerve (CPN) on the spinal reflex and reciprocal inhibition (RI) during robot-assisted passive ground stepping (PGS) in healthy subjects. Five interventions were applied for 30 min in healthy subjects: PGS alone; strong CPN stimulation [50% of the maximal tibialis anterior (TA) M-wave, functional electrical stimulation (FES)] alone; weak CPN stimulation [just above the MT for the TA muscle, therapeutic electrical stimulation (TES)] alone; PGS with FES; and PGS with TES. FES and TES were applied intermittently to the CPN at 25 Hz. The soleus (Sol) H-reflex and RI, which was assessed by conditioning the Sol H-reflex with CPN stimulation, were investigated before (baseline), and 5, 15 and 30 min after each intervention. The amplitudes of the Sol H-reflex were not significantly different after each intervention as compared with the baseline values. The amounts of RI were significantly decreased 5 min after PGS with FES as compared with the baseline values, whereas they were significantly increased 5 and 15 min after PGS with TES. The other interventions did not affect the amount of RI. These results suggest that interventions that combined PGS with CPN stimulation changed the spinal RI in an intensity-dependent manner. PMID:26108136

  13. Short-term effect of electrical nerve stimulation on spinal reciprocal inhibition during robot-assisted passive stepping in humans.

    PubMed

    Obata, Hiroki; Ogawa, Tetsuya; Kitamura, Taku; Masugi, Yohei; Takahashi, Miho; Kawashima, Noritaka; Nakazawa, Kimitaka

    2015-09-01

    The purpose of this study was to investigate the effect of electrical stimulation to the common peroneal nerve (CPN) on the spinal reflex and reciprocal inhibition (RI) during robot-assisted passive ground stepping (PGS) in healthy subjects. Five interventions were applied for 30 min in healthy subjects: PGS alone; strong CPN stimulation [50% of the maximal tibialis anterior (TA) M-wave, functional electrical stimulation (FES)] alone; weak CPN stimulation [just above the MT for the TA muscle, therapeutic electrical stimulation (TES)] alone; PGS with FES; and PGS with TES. FES and TES were applied intermittently to the CPN at 25 Hz. The soleus (Sol) H-reflex and RI, which was assessed by conditioning the Sol H-reflex with CPN stimulation, were investigated before (baseline), and 5, 15 and 30 min after each intervention. The amplitudes of the Sol H-reflex were not significantly different after each intervention as compared with the baseline values. The amounts of RI were significantly decreased 5 min after PGS with FES as compared with the baseline values, whereas they were significantly increased 5 and 15 min after PGS with TES. The other interventions did not affect the amount of RI. These results suggest that interventions that combined PGS with CPN stimulation changed the spinal RI in an intensity-dependent manner.

  14. Eccentric figure-eight coils for transcranial magnetic stimulation.

    PubMed

    Sekino, Masaki; Ohsaki, Hiroyuki; Takiyama, Yoshihiro; Yamamoto, Keita; Matsuzaki, Taiga; Yasumuro, Yoshihiro; Nishikawa, Atsushi; Maruo, Tomoyuki; Hosomi, Koichi; Saitoh, Youichi

    2015-01-01

    Previously we proposed an eccentric figure-eight coil that can cause threshold stimulation in the brain at lower driving currents. In this study, we performed numerical simulations and magnetic stimulations to healthy subjects for evaluating the advantages of the eccentric coil. The simulations were performed using a simplified spherical brain model and a realistic human brain model. We found that the eccentric coil required a driving current intensity of approximately 18% less than that required by the concentric coil to cause comparable eddy current densities within the brain. The eddy current localization of the eccentric coil was slightly higher than that of the concentric coil. A prototype eccentric coil was designed and fabricated. Instead of winding a wire around a bobbin, we cut eccentric-spiral slits on the insulator cases, and a wire was woven through the slits. The coils were used to deliver magnetic stimulation to healthy subjects; among our results, we found that the current slew rate corresponding to motor threshold values for the concentric and eccentric coils were 86 and 78 A/µs, respectively. The results indicate that the eccentric coil consistently requires a lower driving current to reach the motor threshold than the concentric coil. Future development of compact magnetic stimulators will enable the treatment of some intractable neurological diseases at home. PMID:25399864

  15. Transcranial static magnetic field stimulation of the human motor cortex.

    PubMed

    Oliviero, Antonio; Mordillo-Mateos, Laura; Arias, Pablo; Panyavin, Ivan; Foffani, Guglielmo; Aguilar, Juan

    2011-10-15

    The aim of the present study was to investigate in healthy humans the possibility of a non-invasive modulation of motor cortex excitability by the application of static magnetic fields through the scalp. Static magnetic fields were obtained by using cylindrical NdFeB magnets. We performed four sets of experiments. In Experiment 1, we recorded motor potentials evoked by single-pulse transcranial magnetic stimulation (TMS) of the motor cortex before and after 10 min of transcranial static magnetic field stimulation (tSMS) in conscious subjects. We observed an average reduction of motor cortex excitability of up to 25%, as revealed by TMS, which lasted for several minutes after the end of tSMS, and was dose dependent (intensity of the magnetic field) but not polarity dependent. In Experiment 2, we confirmed the reduction of motor cortex excitability induced by tSMS using a double-blind sham-controlled design. In Experiment 3, we investigated the duration of tSMS that was necessary to modulate motor cortex excitability. We found that 10 min of tSMS (compared to 1 min and 5 min) were necessary to induce significant effects. In Experiment 4, we used transcranial electric stimulation (TES) to establish that the tSMS-induced reduction of motor cortex excitability was not due to corticospinal axon and/or spinal excitability, but specifically involved intracortical networks. These results suggest that tSMS using small static magnets may be a promising tool to modulate cerebral excitability in a non-invasive, painless, and reversible way.

  16. Transcranial static magnetic field stimulation of the human motor cortex.

    PubMed

    Oliviero, Antonio; Mordillo-Mateos, Laura; Arias, Pablo; Panyavin, Ivan; Foffani, Guglielmo; Aguilar, Juan

    2011-10-15

    The aim of the present study was to investigate in healthy humans the possibility of a non-invasive modulation of motor cortex excitability by the application of static magnetic fields through the scalp. Static magnetic fields were obtained by using cylindrical NdFeB magnets. We performed four sets of experiments. In Experiment 1, we recorded motor potentials evoked by single-pulse transcranial magnetic stimulation (TMS) of the motor cortex before and after 10 min of transcranial static magnetic field stimulation (tSMS) in conscious subjects. We observed an average reduction of motor cortex excitability of up to 25%, as revealed by TMS, which lasted for several minutes after the end of tSMS, and was dose dependent (intensity of the magnetic field) but not polarity dependent. In Experiment 2, we confirmed the reduction of motor cortex excitability induced by tSMS using a double-blind sham-controlled design. In Experiment 3, we investigated the duration of tSMS that was necessary to modulate motor cortex excitability. We found that 10 min of tSMS (compared to 1 min and 5 min) were necessary to induce significant effects. In Experiment 4, we used transcranial electric stimulation (TES) to establish that the tSMS-induced reduction of motor cortex excitability was not due to corticospinal axon and/or spinal excitability, but specifically involved intracortical networks. These results suggest that tSMS using small static magnets may be a promising tool to modulate cerebral excitability in a non-invasive, painless, and reversible way. PMID:21807616

  17. Repetitive Transcranial Magnetic Stimulation Activates Specific Regions in Rat Brain

    NASA Astrophysics Data System (ADS)

    Ji, Ru-Rong; Schlaepfer, Thomas E.; Aizenman, Carlos D.; Epstein, Charles M.; Qiu, Dike; Huang, Justin C.; Rupp, Fabio

    1998-12-01

    Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique to induce electric currents in the brain. Although rTMS is being evaluated as a possible alternative to electroconvulsive therapy for the treatment of refractory depression, little is known about the pattern of activation induced in the brain by rTMS. We have compared immediate early gene expression in rat brain after rTMS and electroconvulsive stimulation, a well-established animal model for electroconvulsive therapy. Our result shows that rTMS applied in conditions effective in animal models of depression induces different patterns of immediate-early gene expression than does electroconvulsive stimulation. In particular, rTMS evokes strong neural responses in the paraventricular nucleus of the thalamus (PVT) and in other regions involved in the regulation of circadian rhythms. The response in PVT is independent of the orientation of the stimulation probe relative to the head. Part of this response is likely because of direct activation, as repetitive magnetic stimulation also activates PVT neurons in brain slices.

  18. Combinatorial therapy stimulates long-distance regeneration, target reinnervation, and partial recovery of vision after optic nerve injury in mice.

    PubMed

    de Lima, Silmara; Habboub, Ghaith; Benowitz, Larry I

    2012-01-01

    The optic nerve has been widely studied for insights into mechanisms that suppress or promote axon regeneration after central nervous system injury. Following optic nerve damage in adult mammals, retinal ganglion cells (RGCs) normally fail to regenerate their axons, resulting in blindness in patients who suffer from neurodegenerative diseases such as glaucoma or who have sustained traumatic injury to the optic nerve. Over the past several decades, many groups have investigated the basis of regenerative failure in the hope of developing strategies to stimulate the regrowth of axons and restore visual function. New findings show that a combination of therapies that act synergistically to activate RGCs' intrinsic growth state enables these cells to regenerate their axons the full length of the optic nerve, across the optic chiasm, and into the brain, where they establish synapses in appropriate target zones and restore limited visual responses. These treatments involve the induction of a limited inflammatory response in the eye to increase levels of oncomodulin and other growth factors; elevation of intracellular cAMP; and deletion of the pten gene in RGCs. Although these methods cannot be applied in the clinic, they point to strategies that might be.

  19. Comparison of Coil Designs for Transcranial Magnetic Stimulation on Mice

    NASA Astrophysics Data System (ADS)

    Rastogi, Priyam; Hadimani, Ravi; Jiles, David

    2015-03-01

    Transcranial magnetic stimulation (TMS) is a non-invasive treatment for neurological disorders using time varying magnetic field. The electric field generated by the time varying magnetic field is used to depolarize the brain neurons which can lead to measurable effects. TMS provides a surgical free method for the treatment of neurological brain disorders like depression, post-traumatic stress disorder, traumatic brain injury and Parkinson's disease. Before using TMS on human subjects, it is appropriate that its effects are verified on animals such as mice. The magnetic field intensity and stimulated region of the brain can be controlled by the shape, position and current in the coils. There are few reports on the designs of the coils for mice. In this paper, different types of coils are developed and compared using an anatomically realistic mouse model derived from MRI images. Parameters such as focality, depth of the stimulation, electric field strength on the scalp and in the deep brain regions, are taken into account. These parameters will help researchers to determine the most suitable coil design according to their need. This should result in improvements in treatment of specific disorders. Carver Charitable Trust.

  20. Responses to magnetic stimuli recorded in peripheral nerves in the marine nudibranch mollusk Tritonia diomedea.

    PubMed

    Pavlova, Galina A; Glantz, Raymon M; Dennis Willows, A O

    2011-10-01

    Prior behavioral and neurophysiological studies provide evidence that the nudibranch mollusk Tritonia orients to the earth's magnetic field. Earlier studies of electrophysiological responses in certain neurons of the brain to changing ambient magnetic fields suggest that although certain identified brain cells fire impulses when the ambient field is changed, these neuron somata and their central dentritic and axonal processes are themselves not primary magnetic receptors. Here, using semi-intact animal preparations from which the brain was removed, we recorded from peripheral nerve trunks. Using techniques to count spikes in individual nerves and separately also to identify, then count individual axonal spikes in extracellular records, we found both excitatory and inhibitory axonal responses elicited by changes in the direction of ambient earth strength magnetic fields. We found responses in nerves from many locations throughout the body and in axons innervating the body wall and rhinophores. Our results indicate that primary receptors for geomagnetism in Tritonia are not focally concentrated in any particular organ, but appear to be widely dispersed in the peripheral body tissues. PMID:21717186

  1. ANATOMICAL STUDY OF CRANIAL NERVE EMERGENCE AND SKULL FORAMINA IN THE HORSE USING MAGNETIC RESONANCE IMAGING AND COMPUTED TOMOGRAPHY.

    PubMed

    Gonçalves, Rita; Malalana, Fernando; McConnell, James Fraser; Maddox, Thomas

    2015-01-01

    For accurate interpretation of magnetic resonance (MR) images of the equine brain, knowledge of the normal cross-sectional anatomy of the brain and associated structures (such as the cranial nerves) is essential. The purpose of this prospective cadaver study was to describe and compare MRI and computed tomography (CT) anatomy of cranial nerves' origins and associated skull foramina in a sample of five horses. All horses were presented for euthanasia for reasons unrelated to the head. Heads were collected posteuthanasia and T2-weighted MR images were obtained in the transverse, sagittal, and dorsal planes. Thin-slice MR sequences were also acquired using transverse 3D-CISS sequences that allowed mutliplanar reformatting. Transverse thin-slice CT images were acquired and multiplanar reformatting was used to create comparative images. Magnetic resonance imaging consistently allowed visualization of cranial nerves II, V, VII, VIII, and XII in all horses. The cranial nerves III, IV, and VI were identifiable as a group despite difficulties in identification of individual nerves. The group of cranial nerves IX, X, and XI were identified in 4/5 horses although the region where they exited the skull was identified in all cases. The course of nerves II and V could be followed on several slices and the main divisions of cranial nerve V could be distinguished in all cases. In conclusion, CT allowed clear visualization of the skull foramina and occasionally the nerves themselves, facilitating identification of the nerves for comparison with MRI images.

  2. Measurement of evoked electroencephalography induced by transcranial magnetic stimulation

    NASA Astrophysics Data System (ADS)

    Iramina, Keiji; Maeno, Takashi; Nonaka, Yukio; Ueno, Shoogo

    2003-05-01

    This study focused on the measurement of evoked potentials induced by transcranial magnetic stimulation (TMS) for observing the neuronal connectivity in the brain. We developed an electroencephalography (EEG) measurement system to eliminate the electromagnetic interaction emitted from TMS. EEG activities 5 ms after TMS stimulation were measured. Using this artifact free amplifier, we investigated the intensity dependence of brain activation induced by TMS. When the stimulus intensity was changed at three levels, TMS-evoked EEG responses were measured. Several components of the evoked potential appeared at 9 ms, 20 ms, and 50 ms after stimulation. A large response appeared at about 9 ms after cerebellar TMS. There was a significant dependence of these responses on the stimulus intensity. During right-hand side motor area stimulation, there was no clear peak of the wave forms within 10 ms latency. Occipital stimulation caused more evoked responses to spread to the center of the brain than at other areas of stimulation. The evoked signal by TMS was possibly conducted posteriorly to anteriorly along the pathways of the neuronal fiber exiting the cerebellum into the cerebral cortex.

  3. Inhibitory transcranial magnetic theta burst stimulation attenuates prefrontal cortex oxygenation.

    PubMed

    Tupak, Sara V; Dresler, Thomas; Badewien, Meike; Hahn, Tim; Ernst, Lena H; Herrmann, Martin J; Deckert, Jürgen; Ehlis, Ann-Christine; Fallgatter, Andreas J

    2013-01-01

    Recent studies highlighted the great potential of newly established theta burst stimulation (TBS) protocols for non-invasive human brain stimulation studies using transcranial magnetic stimulation (TMS). While intermittent TBS over the primary motor cortex was found to potentiate motor evoked potentials, continuous TBS led to profound attenuations. Although numerous studies investigated the impact of TBS on motor cortex function, yet, only few imaging studies focused on its effects in other brain areas. Particularly for the prefrontal cortex, it is unclear whether TBS has similar effects compared to application over motor areas. In the current study continuous TBS was applied to either the left or right dorsolateral prefrontal cortex in a sample of healthy subjects. Changes in prefrontal oxygenation were measured during an emotional Stroop task by means of functional multi-channel near-infrared spectroscopy (fNIRS) before and after stimulation. Results showed bilaterally decreased prefrontal oxygenation following inhibitory stimulation of the left prefrontal cortex but no behavioral effect. No such alterations were observed following right-hemispheric or sham stimulation. The results of the current study are in line with earlier findings and additionally demonstrate that also prefrontal oxygenation can be impaired by continuous TBS.

  4. Improved transcranial magnetic stimulation coil design with realistic head modeling

    NASA Astrophysics Data System (ADS)

    Crowther, Lawrence; Hadimani, Ravi; Jiles, David

    2013-03-01

    We are investigating Transcranial magnetic stimulation (TMS) as a noninvasive technique based on electromagnetic induction which causes stimulation of the neurons in the brain. TMS can be used as a pain-free alternative to conventional electroconvulsive therapy (ECT) which is still widely implemented for treatment of major depression. Development of improved TMS coils capable of stimulating subcortical regions could also allow TMS to replace invasive deep brain stimulation (DBS) which requires surgical implantation of electrodes in the brain. Our new designs allow new applications of the technique to be established for a variety of diagnostic and therapeutic applications of psychiatric disorders and neurological diseases. Calculation of the fields generated inside the head is vital for the use of this method for treatment. In prior work we have implemented a realistic head model, incorporating inhomogeneous tissue structures and electrical conductivities, allowing the site of neuronal activation to be accurately calculated. We will show how we utilize this model in the development of novel TMS coil designs to improve the depth of penetration and localization of stimulation produced by stimulator coils.

  5. An artificial arm/hand system with a haptic sensory function using electric stimulation of peripheral sensory nerve fibers.

    PubMed

    Mabuchi, Kunihiko

    2013-01-01

    We are currently developing an artificial arm/hand system which is capable of sensing stimuli and then transferring these stimuli to users as somatic sensations. Presently, we are evoking the virtual somatic sensations by electrically stimulating a sensory nerve fiber which innervates a single mechanoreceptor unit at the target area; this is done using a tungsten microelectrode that was percutaneously inserted into the use's peripheral nerve (a microstimulation method). The artificial arm/hand system is composed of a robot hand equipped with a pressure sensor system on its fingers. The sensor system detects mechanical stimuli, which are transferred to the user by means of the microstimulation method so that the user experiences the stimuli as the corresponding somatic sensations. In trials, the system worked satisfactorily and there was a good correlation between the pressure applied to the pressure sensors on the robot fingers and the subjective intensities of the evoked pressure sensations.

  6. Comparison of Transcutaneous Electrical Nerve Stimulation and Pulsed Radiofrequency Sympathectomy for Treating Painful Diabetic Neuropathy

    PubMed Central

    Naderi Nabi, Bahram; Sedighinejad, Abbas; Haghighi, Mohammad; Biazar, Gelareh; Hashemi, Masood; Haddadi, Soodabeh; Fathi, Amirhossein

    2015-01-01

    Background: Painful diabetic peripheral neuropathy (DPN) is a long-term complication of type 1 and type 2 diabetes that majorly impacts quality of life. Its prevalence increases with age and duration of diabetes. It is more common in patients who have suboptimal glycemic control over several years. Because DPN may be resistant to conventional treatments, it is common for patients to only have partial pain relief. Therefore, new therapeutic options are needed for the condition. Objectives: The aim of the present study was to compare the efficacy of transcutaneous electrical nerve stimulation (TENS) and pulsed radiofrequency (PRF) lumbar sympathectomy in treating painful DPN. Patients and Methods: Sixty-five patients with painful DPN refractory to conventional treatment were randomly and evenly assigned to either the TENS or PRF lumbar sympathectomy groups. Pain evaluations were based on the 10-point numerical rating scale (NRS). Subjects were followed for three months and had a total of four study visits (baseline and 1 week, 1 month, and 3 months after treatment). Results: Sixty patients completed all study visits. In both groups, the NRS rating significantly decreased after treatment, with a marked pain reduction observed at the first follow-up evaluation. In the PRF group, the NRS decreased from 6.46 at baseline to 2.76 at the 1 week visit. One and 3 months after treatment, the NRS was 4.30 and 5.13, respectively (P < 0.0001). In the TENS group, the NRS decreased from 6.10 at baseline to 3.96 at the 1 week visit. One and 3 months after treatment, the NRS was 5.23 and 5.90, respectively (P < 0.0001). Unfortunately, the NRS steady increased almost back to baseline levels in the TENS group. The NRS only slightly increased during the follow-up period in the PRF group, but did not reach baseline levels. Conclusions: Both TENS and PRF lumbar sympathectomy are promising pain relief treatments for painful DNP. However, PRF lumbar sympathectomy seems to have a superior

  7. Spinal autofluorescent flavoprotein imaging in a rat model of nerve injury-induced pain and the effect of spinal cord stimulation.

    PubMed

    Jongen, Joost L M; Smits, Helwin; Pederzani, Tiziana; Bechakra, Malik; Hossaini, Mehdi; Koekkoek, Sebastiaan K; Huygen, Frank J P M; De Zeeuw, Chris I; Holstege, Jan C; Joosten, Elbert A J

    2014-01-01

    Nerve injury may cause neuropathic pain, which involves hyperexcitability of spinal dorsal horn neurons. The mechanisms of action of spinal cord stimulation (SCS), an established treatment for intractable neuropathic pain, are only partially understood. We used Autofluorescent Flavoprotein Imaging (AFI) to study changes in spinal dorsal horn metabolic activity. In the Seltzer model of nerve-injury induced pain, hypersensitivity was confirmed using the von Frey and hotplate test. 14 Days after nerve-injury, rats were anesthetized, a bipolar electrode was placed around the affected sciatic nerve and the spinal cord was exposed by a laminectomy at T13. AFI recordings were obtained in neuropathic rats and a control group of naïve rats following 10 seconds of electrical stimulation of the sciatic nerve at C-fiber strength, or following non-noxious palpation. Neuropathic rats were then treated with 30 minutes of SCS or sham stimulation and AFI recordings were obtained for up to 60 minutes after cessation of SCS/sham. Although AFI responses to noxious electrical stimulation were similar in neuropathic and naïve rats, only neuropathic rats demonstrated an AFI-response to palpation. Secondly, an immediate, short-lasting, but strong reduction in AFI intensity and area of excitation occurred following SCS, but not following sham stimulation. Our data confirm that AFI can be used to directly visualize changes in spinal metabolic activity following nerve injury and they imply that SCS acts through rapid modulation of nociceptive processing at the spinal level. PMID:25279562

  8. Prognostic value of cortical magnetic stimulation in spinal cord injury.

    PubMed

    Clarke, C E; Modarres-Sadeghi, H; Twomey, J A; Burt, A A

    1994-08-01

    Cortical magnetic stimulation was performed in a consecutive series of 10 patients presenting within 15 days of traumatic spinal cord injury. In those patients with complete paraplegia or quadriplegia, motor evoked potentials at presentation were absent below the level of the lesion. Six months after the injury, potentials had returned in the biceps brachii and abductor pollicis brevis muscles in some quadriplegic cases, but remained absent from the tibialis anterior in all of this group. None of those with a complete lesion made a significant functional recovery. Of the three patients with incomplete quadriplegia, two showed a significant recovery after 6 months. Motor evoked potentials were recordable below the level of the lesion at presentation in these cases, although the latencies were prolonged. In the remaining patient who failed to improve, potentials were unrecordable throughout the study. This small pilot study suggests that cortical magnetic stimulation may be useful in refining the prognosis in patients with an incomplete spinal cord injury. PMID:7970860

  9. Transcranial magnetic stimulation for the treatment of major depression

    PubMed Central

    Janicak, Philip G; Dokucu, Mehmet E

    2015-01-01

    Major depression is often difficult to diagnose accurately. Even when the diagnosis is properly made, standard treatment approaches (eg, psychotherapy, medications, or their combination) are often inadequate to control acute symptoms or maintain initial benefit. Additional obstacles involve safety and tolerability problems, which frequently preclude an adequate course of treatment. This leaves an important gap in our ability to properly manage major depression in a substantial proportion of patients, leaving them vulnerable to ensuing complications (eg, employment-related disability, increased risk of suicide, comorbid medical disorders, and substance abuse). Thus, there is a need for more effective and better tolerated approaches. Transcranial magnetic stimulation is a neuromodulation technique increasingly used to partly fill this therapeutic void. In the context of treating depression, we critically review the development of transcranial magnetic stimulation, focusing on the results of controlled and pragmatic trials for depression, which consider its efficacy, safety, and tolerability. PMID:26170668

  10. Benign paroxysmal positional vertigo following diagnostic transcranial magnetic stimulation.

    PubMed

    Strzelczyk, Adam; Kepenek, Yildiz; Rindock, Heike; Müller-Mazzotta, Jochen; Oertel, Wolfgang H; Mylius, Veit; Rosenow, Felix

    2011-06-01

    Benign paroxysmal positional vertigo is the most frequent cause of recurrent vertigo and according to the canalo- and cupulolithiasis theory it is caused by detached otoconia which accumulate in the semicircular canals. However, the mechanisms leading to detachment of otoconia from the matrix are still poorly understood. Head trauma, inner ear diseases, advanced age, migraine and bed rest are known predisposing factors. We report a case of a healthy 44-year-old female, who developed left sided benign paroxysmal positional vertigo 10 hours following standard bilateral diagnostic transcranial magnetic stimulation. As our patient did not innate any established predisposing factor and has a relatively young age, we conclude that diagnostic transcranial magnetic stimulation to elicit motor evoked potentials might be an iatrogenic cause of benign paroxysmal positional vertigo.

  11. Recovery Effect of the Muscle Fatigue by the Magnetic Stimulation

    NASA Astrophysics Data System (ADS)

    Uchida, Kousuke; Nuruki, Atsuo; Tsujimura, Sei-Ichi; Tamari, Youzou; Yunokuchi, Kazutomo

    The purpose of this study is to investigate the effect of magnetic stimulation for muscle fatigue. The six healthy subjects participated in the experiment with the repetition grasp using a hand dynamometer. The measurement of EMG (electromyography) and MMG (mechanomyography) is performed on the left forearm. All subjects performed MVC (maximum voluntary contraction), and repeated exercise in 80%MVC after the MVC measurement. The repetition task was entered when display muscular strength deteriorated. We used an EMG and MMG for the measurement of the muscle fatigue. Provided EMG and MMG waves were calculated integral calculus value (iEMG, and iMMG). The result of iEMG and iMMG were divided by muscular strength, because we calculate integral calculus value per the unit display muscular strength. The result of our study, we found recovery effect by the magnetic stimulation in voluntarily muscular strength and iEMG. However, we can not found in a figure of iMMG.

  12. Modulation of sensorimotor cortex by repetitive peripheral magnetic stimulation

    PubMed Central

    Gallasch, Eugen; Christova, Monica; Kunz, Alexander; Rafolt, Dietmar; Golaszewski, Stefan

    2015-01-01

    This study examines with transcranial magnetic stimulation (TMS) and with functional magnetic resonance imaging (fMRI) whether 20 min of repetitive peripheral magnetic stimulation (rPMS) has a facilitating effect on associated motor controlling regions. Trains of rPMS with a stimulus intensity of 150% of the motor threshold (MT) were applied over right hand flexor muscles of healthy volunteers. First, with TMS, 10 vs. 25 Hz rPMS was examined and compared to a control group. Single and paired pulse motor evoked potentials (MEPs) from flexor carpi radialis (FCR) and extensor carpi radialis (ECR) muscles were recorded at baseline (T0), post rPMS (T1), 30 min post (T2), 1 h post (T3) and 2 h post rPMS (T4). Then, with fMRI, 25 Hz rPMS was compared to sham stimulation by utilizing a finger tapping activation paradigm. Changes in bloodoxygen level dependent (BOLD) contrast were examined at baseline (PRE), post rPMS (POST1) and 1 h post rPMS (POST2). With TMS facilitation was observed in the target muscle (FCR) following 25 Hz rPMS: MEP recruitment curves (RCs) were increased at T1, T2 and T3, and intracortical facilitation (ICF) was increased at T1 and T2. No effects were observed following 10 Hz rPMS. With fMRI the BOLD contrast at the left sensorimotor area was increased at POST1. Compared to inductions protocols based on transcutaneous electrical stimulation and mechanical stimulation, the rPMS induced effects appeared shorter lasting. PMID:26236220

  13. Modulation of cortical oscillatory activity during transcranial magnetic stimulation.

    PubMed

    Brignani, Debora; Manganotti, Paolo; Rossini, Paolo M; Miniussi, Carlo

    2008-05-01

    Transcranial magnetic stimulation (TMS) can transiently modulate cortical excitability, with a net effect depending on the stimulation frequency (< or =1 Hz inhibition vs. > or =5 Hz facilitation, at least for the motor cortex). This possibility has generated interest in experiments aiming to improve deficits in clinical settings, as well as deficits in the cognitive domain. The aim of the present study was to investigate the on-line effects of low frequency (1 Hz) TMS on the EEG oscillatory activity in the healthy human brain, focusing particularly on the outcome of these modulatory effects in relation to the duration of the TMS stimulation. To this end, we used the event-related desynchronization/synchronization (ERD/ERS) approach to determine the patterns of oscillatory activity during two consecutive trains of sham and real TMS. Each train of stimulation was delivered to the left primary motor cortex (MI) of healthy subjects over a period of 10 min, while EEG rhythms were simultaneously recorded. Results indicated that TMS induced an increase in the power of brain rhythms that was related to the period of the stimulation, i.e. the synchronization of the alpha band increased with the duration of the stimulation, and this increase was inversely correlated with motor-evoked potentials (MEPs) amplitude. In conclusion, low frequency TMS over primary motor cortex induces a synchronization of the background oscillatory activity on the stimulated region. This induced modulation in brain oscillations seems to increase coherently with the duration of stimulation, suggesting that TMS effects may involve short-term modification of the neural circuitry sustaining MEPs characteristics. PMID:17557296

  14. Long-term seizure and psychosocial outcomes of vagus nerve stimulation for intractable epilepsy.

    PubMed

    Wasade, Vibhangini S; Schultz, Lonni; Mohanarangan, Karthik; Gaddam, Aryamaan; Schwalb, Jason M; Spanaki-Varelas, Marianna

    2015-12-01

    Vagus nerve stimulation (VNS) is a widely used adjunctive treatment option for intractable epilepsy. Most studies have demonstrated short-term seizure outcomes, usually for up to 5 years, and thus far, none have reported psychosocial outcomes in adults. We aimed to assess long-term seizure and psychosocial outcomes in patients with intractable epilepsy on VNS therapy for more than 15 years. We identified patients who had VNS implantation for treatment of intractable epilepsy from 1997 to 2013 at our Comprehensive Epilepsy Program and gathered demographics including age at epilepsy onset and VNS implantation, epilepsy type, number of antiepilepsy drugs (AEDs) and seizure frequency before VNS implantation and at the last clinic visit, and the most recent stimulation parameters from electronic medical records (EMR). Phone surveys were conducted by research assistants from May to November 2014 to determine patients' current seizure frequency and psychosocial metrics, including driving, employment status, and use of antidepressants. Seizure outcomes were based on modified Engel classification (I: seizure-free/rare simple partial seizures; II: >90% seizure reduction (SR), III: 50-90% SR, IV: <50% SR; classes I to III (>50% SR)=favorable outcome). A total of 207 patients underwent VNS implantation, 15 of whom were deceased at the time of the phone survey, and 40 had incomplete data for medical abstraction. Of the remaining 152, 90 (59%) were contacted and completed the survey. Of these, 51% were male, with the mean age at epilepsy onset of 9.4 years (range: birth to 60 years). There were 35 (39%) patients with extratemporal epilepsy, 19 (21%) with temporal, 18 (20%) with symptomatic generalized, 5 (6%) with idiopathic generalized, and 13 (14%) with multiple types. Final VNS settings showed 16 (18%) patients with an output current >2 mA and 14 (16%) with rapid cycling. Of the 80 patients with seizure frequency information, 16 (20%) had a modified Engel class I outcome, 14

  15. Long-term seizure and psychosocial outcomes of vagus nerve stimulation for intractable epilepsy.

    PubMed

    Wasade, Vibhangini S; Schultz, Lonni; Mohanarangan, Karthik; Gaddam, Aryamaan; Schwalb, Jason M; Spanaki-Varelas, Marianna

    2015-12-01

    Vagus nerve stimulation (VNS) is a widely used adjunctive treatment option for intractable epilepsy. Most studies have demonstrated short-term seizure outcomes, usually for up to 5 years, and thus far, none have reported psychosocial outcomes in adults. We aimed to assess long-term seizure and psychosocial outcomes in patients with intractable epilepsy on VNS therapy for more than 15 years. We identified patients who had VNS implantation for treatment of intractable epilepsy from 1997 to 2013 at our Comprehensive Epilepsy Program and gathered demographics including age at epilepsy onset and VNS implantation, epilepsy type, number of antiepilepsy drugs (AEDs) and seizure frequency before VNS implantation and at the last clinic visit, and the most recent stimulation parameters from electronic medical records (EMR). Phone surveys were conducted by research assistants from May to November 2014 to determine patients' current seizure frequency and psychosocial metrics, including driving, employment status, and use of antidepressants. Seizure outcomes were based on modified Engel classification (I: seizure-free/rare simple partial seizures; II: >90% seizure reduction (SR), III: 50-90% SR, IV: <50% SR; classes I to III (>50% SR)=favorable outcome). A total of 207 patients underwent VNS implantation, 15 of whom were deceased at the time of the phone survey, and 40 had incomplete data for medical abstraction. Of the remaining 152, 90 (59%) were contacted and completed the survey. Of these, 51% were male, with the mean age at epilepsy onset of 9.4 years (range: birth to 60 years). There were 35 (39%) patients with extratemporal epilepsy, 19 (21%) with temporal, 18 (20%) with symptomatic generalized, 5 (6%) with idiopathic generalized, and 13 (14%) with multiple types. Final VNS settings showed 16 (18%) patients with an output current >2 mA and 14 (16%) with rapid cycling. Of the 80 patients with seizure frequency information, 16 (20%) had a modified Engel class I outcome, 14

  16. Novel insights into maladaptive behaviours in Prader–Willi syndrome: serendipitous findings from an open trial of vagus nerve stimulation

    PubMed Central

    McAllister, C. J.; Ring, H. A.; Finer, N.; Kelly, C. L.; Sylvester, K. P.; Fletcher, P. C.; Morrell, N. W.; Garnett, M. R.; Manford, M. R. A.; Holland, A. J.

    2015-01-01

    Abstract Background We report striking and unanticipated improvements in maladaptive behaviours in Prader–Willi syndrome (PWS) during a trial of vagus nerve stimulation (VNS) initially designed to investigate effects on the overeating behaviour. PWS is a genetically determined neurodevelopmental disorder associated with mild–moderate intellectual disability (ID) and social and behavioural difficulties, alongside a characteristic and severe hyperphagia. Methods Three individuals with PWS underwent surgery to implant the VNS device. VNS was switched on 3 months post‐implantation, with an initial 0.25 mA output current incrementally increased to a maximum of 1.5 mA as tolerated by each individual. Participants were followed up monthly. Results Vagal nerve stimulation in these individuals with PWS, within the stimulation parameters used here, was safe and acceptable. However, changes in eating behaviour were equivocal. Intriguingly, unanticipated, although consistent, beneficial effects were reported by two participants and their carers in maladaptive behaviour, temperament and social functioning. These improvements and associated effects on food‐seeking behaviour, but not weight, indicate that VNS may have potential as a novel treatment for such behaviours. Conclusions We propose that these changes are mediated through afferent and efferent vagal projections and their effects on specific neural networks and functioning of the autonomic nervous system and provide new insights into the mechanisms that underpin what are serious and common problems affecting people with IDs more generally. PMID:26018613

  17. Persistent effects after trigeminal nerve proprioceptive stimulation by mandibular extension on rat blood pressure, heart rate and pial microcirculation.

    PubMed

    Lapi, D; Colantuoni, A; Del Seppia, C; Ghione, S; Tonlorenzi, D; Brunelli, M; Scuri, R

    2013-03-01

    The trigemino-cardiac reflex is a brainstem reflex known to lead to a decrement in heart rate and blood pressure, whereas few data have been collected about its effects on the cerebral hemodynamic. In this study we assess the in vivo effects of trigeminal nerve peripheral stimulation by mandibular extension on pial microcirculation and systemic arterial blood pressure in rats. Experiments were performed in male Wistar rats subjected to mandibular extension obtained inserting an ad hoc developed retractor between the dental arches. Mean arterial blood pressure and heart rate were recorded and the pial arterioles were visualized by fluorescence microscopy to measure the vessel diameters before (15 minutes) during (5-15 minutes) and after (80 minutes) mandibular extension. While in control rats (sham-operated rats) and in rats subjected to the dissection of the trigeminal peripheral branches mean arterial blood pressure, heart rate and pial microcirculation did not change during the whole observation period (110 minutes), in rats submitted to mandibular extension, mean arterial blood pressure, heart rate and arteriolar diameter significantly decreased during stimulation. Afterward mean arterial blood pressure remained reduced as well as heart rate, while arteriolar diameter significantly increased evidencing a vasodilatation persisting for the whole remaining observation time. Therefore, trigeminal nerve proprioceptive stimulation appears to trigger specific mechanisms regulating systemic arterial blood pressure and pial microcirculation.

  18. Application of a Rat Hindlimb Model: A Prediction of Force Spaces Reachable Through Stimulation of Nerve Fascicles

    PubMed Central

    Johnson, Will L.; Jindrich, Devin L.; Zhong, Hui; Roy, Roland R.

    2011-01-01

    A device to generate standing or locomotion through chronically placed electrodes has not been fully developed due in part to limitations of clinical experimentation and the high number of muscle activation inputs of the leg. We investigated the feasibility of functional electrical stimulation paradigms that minimize the input dimensions for controlling the limbs by stimulating at nerve fascicles, utilizing a model of the rat hindlimb which combined previously collected morphological data with muscle physiological parameters presented herein. As validation of the model we investigated the suitability of a lumped-parameter model for prediction of muscle activation during dynamic tasks. Using the validated model we found that the space of forces producible through activation of muscle groups sharing common nerve fascicles was nonlinearly dependent on the number of discrete muscle groups that could be individually activated (equivalently, the neuroanatomical level of activation). Seven commonly innervated muscle groups were sufficient to produce 78% of the force space producible through individual activation of the 42 modeled hindlimb muscles. This novel, neuroanatomically derived reduction in input dimension emphasizes the potential to simplify controllers for functional electrical stimulation to improve functional recovery after a neuromuscular injury. PMID:21244999

  19. Deep brain transcranial magnetic stimulation using variable "Halo coil" system

    NASA Astrophysics Data System (ADS)

    Meng, Y.; Hadimani, R. L.; Crowther, L. J.; Xu, Z.; Qu, J.; Jiles, D. C.

    2015-05-01

    Transcranial Magnetic Stimulation has the potential to treat various neurological disorders non-invasively and safely. The "Halo coil" configuration can stimulate deeper regions of the brain with lower surface to deep-brain field ratio compared to other coil configurations. The existing "Halo coil" configuration is fixed and is limited in varying the site of stimulation in the brain. We have developed a new system based on the current "Halo coil" design along with a graphical user interface system that enables the larger coil to rotate along the transverse plane. The new system can also enable vertical movement of larger coil. Thus, this adjustable "Halo coil" configuration can stimulate different regions of the brain by adjusting the position and orientation of the larger coil on the head. We have calculated magnetic and electric fields inside a MRI-derived heterogeneous head model for various positions and orientations of the coil. We have also investigated the mechanical and thermal stability of the adjustable "Halo coil" configuration for various positions and orientations of the coil to ensure safe operation of the system.

  20. [Repetitive transcranial magnetic stimulation in depression; stimulation of the brain in order to cure the psyche].

    PubMed

    Helmich, R C; Snijders, A H; Verkes, R J; Bloem, B R

    2004-02-28

    Transcranial magnetic stimulation (TMS) is a non-invasive approach to briefly stimulate or inhibit cortical brain areas. A novel approach entails the delivery of repetitive TMS pulses (rTMS) at a fixed frequency. In rTMS cortical activity is altered beyond the period of actual stimulation. The changes occur locally as well as at a distance in functionally connected brain areas. These features render rTMS a suitable tool to study normal brain functions and the pathophysiology of brain diseases. Furthermore, it is expected that rTMS could be used as a novel therapy for neurological or psychiatric diseases characterised by abnormal cortical activation. This possibility has been studied mostly in patients suffering from depression, where rTMS has been used to restore normal activity in the hypoactive prefrontal cortex. Despite statistically significant therapeutic effects in small sized trials, the clinical implications are still limited.

  1. Electrical vagus nerve stimulation decreases food consumption and weight gain in rats fed a high-fat diet.

    PubMed

    Gil, Krzysztof; Bugajski, A; Thor, P

    2011-12-01

    There is growing evidence that vagus nerve stimulation (VNS) has a suppressive effect on both short- and long-term feeding in animal models. We previously showed that long-term VNS (102 days) with low-frequency electrical impulses (0.05 Hz) decreased food intake and body weight in rats. In the present study, we investigated the effect of high frequency (10 Hz) VNS on feeding behavior and appetite in rats fed a high-fat diet; peptide secretion and other parameters were assessed as well. Adult male Wistar rats were each implanted subcutaneously with a microstimulator (MS) and fed a high-fat diet throughout the entire study period (42 days). The left vagus nerve was stimulated by rectangular electrical pulses (10 ms, 200 mV, 10 Hz, 12 h a day) generated by the MS. Body weight and food intake were measured each morning. At the end of the experimental period, animals were euthanized and blood samples were taken. Serum levels of ghrelin, leptin and nesfatin-1 were assessed using radioimmunoassays. Adipose tissue content was evaluated by weighing epididymal fat pads, which were incised at the time of sacrifice. To determine whether VNS activated the food-related areas of the brain, neuronal c-Fos induction in the nuclei of the solitary tract (NTS) was assessed. Chronic vagus nerve stimulation significantly decreased food intake, body weight gain and epididymal fat pad weight in animals that received VNS compared with control animals. Significant neuronal responses in the NTS were observed following VNS. Finally, serum concentrations of ghrelin were increased, while serum levels of leptin were decreased. Although not significant, serum nesfatin-1 levels were also elevated. These results support the theory that VNS leads to reductions in food intake, body weight gain and adipose tissue by increasing brain satiety signals conducted through the vagal afferents. VNS also evoked a feed-related hormonal response, including elevated blood concentrations of nesfatin-1.

  2. Spatiotemporal characteristics of cerebral blood volume changes in different microvascular compartments evoked by sciatic nerve stimulation in rat somatosensory cortex

    NASA Astrophysics Data System (ADS)

    Li, Pengcheng; Luo, Qingming; Luo, Weihua; Chen, Shanbin; Cheng, Haiying; Zeng, Shaoqun

    2003-07-01

    The spatio-temporal characteristics of changes in cerebral blood volume associated with neuronal activity were investigated in the hindlimb somatosensory cortex of α-chloralose/urethan anesthetized rats (n=10) with optical imaging at 570nm through a thinned skull. Activation of cortex was carried out by electrical stimulation of the contralateral sciatic nerve with 5Hz, 0.3V pulses (0.5ms) for duration of 2s. The stimulation evoked a monophasic optical reflectance decrease at cortical parenchyma and arteries sites rapidly after the onset of stimulation, whereas no similar response was observed at vein compartments. The optical signal changes reached 10% of the peak response 0.70+/-0.32s after stimulation onset and no significant time lag in this 10% start latency time was observed between the response at cortical parenchyma and arteries compartments. The evoked optical reflectance decrease reached the peak (0.25%+/-0.047%) 2.66+/-0.61s after the stimulus onset at parenchyma site, 0.40+/-0.20s earlier (P<0.05) than that at arteries site (0.50+/-0.068% 3.06+/-0.70s). Variable location within the cortical parenchyma and arteries compartment themselves didn"t affect the temporal characteristics of the evoked signal significantly. These results suggest that the sciatic nerve stimulation evokes a local blood volume increase at both capillaries (cortical parenchyma) and arterioles rapidly after the stimulus onset but the evoked blood volume increase in capillaries could not be entirely accounted for by the dilation of arterioles.

  3. Comparison of dopamine kinetics in the larval Drosophila ventral nerve cord and protocerebrum with improved optogenetic stimulation.

    PubMed

    Privman, Eve; Venton, B Jill

    2015-11-01

    Dopamine release and uptake have been studied in the Drosophila larval ventral nerve cord (VNC) using optogenetics to stimulate endogenous release. However, other areas of the central nervous system remain uncharacterized. Here, we compare dopamine release in the VNC and protocerebrum of larval Drosophila. Stimulations were performed with CsChrimson, a new, improved, red light-activated channelrhodopsin. In both regions, dopamine release was observed after only a single, 4 ms duration light pulse. Michaelis-Menten modeling was used to understand release and uptake parameters for dopamine. The amount of dopamine released ([DA]p ) on the first stimulation pulse is higher than the average [DA]p released from subsequent pulses. The initial and average amount of dopamine released per stimulation pulse is smaller in the protocerebrum than in the VNC. The average Vmax of 0.08 μM/s in the protocerebrum was significantly higher than the Vmax of 0.05 μM/s in the VNC. The average Km of 0.11 μM in the protocerebrum was not significantly different from the Km of 0.10 μM in the VNC. When the competitive dopamine transporter (DAT) inhibitor nisoxetine was applied, the Km increased significantly in both regions while Vmax stayed the same. This work demonstrates regional differences in dopamine release and uptake kinetics, indicating important variation in the amount of dopamine available for neurotransmission and neuromodulation. We use a new optogenetic tool, red light activated CsChrimson, to stimulate the release of dopamine in the ventral nerve cord and medial protocerebrum of the larval Drosophila central nervous system. We monitored extracellular dopamine by fast scan cyclic voltammetry and used Michaelis-Menten modeling to probe the regulation of extracellular dopamine, discovering important similarities and differences in these two regions.

  4. Magnetic resonance imaging safety of deep brain stimulator devices.

    PubMed

    Oluigbo, Chima O; Rezai, Ali R

    2013-01-01

    Magnetic resonance imaging (MRI) has become the standard of care for the evaluation of different neurological disorders of the brain and spinal cord due to its multiplanar capabilities and excellent soft tissue resolution. With the large and increasing population of patients with implanted deep brain stimulation (DBS) devices, a significant proportion of these patients with chronic neurological diseases require evaluation of their primary neurological disease processes by MRI. The presence of an implanted DBS device in a magnetic resonance environment presents potential hazards. These include the potential for induction of electrical currents or heating in DBS devices, which can result in neurological tissue injury, magnetic field-induced device migration, or disruption of the operational aspects of the devices. In this chapter, we review the basic physics of potential interactions of the MRI environment with implanted DBS devices, summarize results from phantom studies and clinical series, and discuss present recommendations for safe MRI in patients with implanted DBS devices.

  5. Magnetic resonance imaging safety of deep brain stimulator devices.

    PubMed

    Oluigbo, Chima O; Rezai, Ali R

    2013-01-01

    Magnetic resonance imaging (MRI) has become the standard of care for the evaluation of different neurological disorders of the brain and spinal cord due to its multiplanar capabilities and excellent soft tissue resolution. With the large and increasing population of patients with implanted deep brain stimulation (DBS) devices, a significant proportion of these patients with chronic neurological diseases require evaluation of their primary neurological disease processes by MRI. The presence of an implanted DBS device in a magnetic resonance environment presents potential hazards. These include the potential for induction of electrical currents or heating in DBS devices, which can result in neurological tissue injury, magnetic field-induced device migration, or disruption of the operational aspects of the devices. In this chapter, we review the basic physics of potential interactions of the MRI environment with implanted DBS devices, summarize results from phantom studies and clinical series, and discuss present recommendations for safe MRI in patients with implanted DBS devices. PMID:24112886

  6. Using independent component analysis to remove artifacts in visual cortex responses elicited by electrical stimulation of the optic nerve

    NASA Astrophysics Data System (ADS)

    Lu, Yiliang; Cao, Pengjia; Sun, Jingjing; Wang, Jing; Li, Liming; Ren, Qiushi; Chen, Yao; Chai, Xinyu

    2012-04-01

    In visual prosthesis research, electrically evoked potentials (EEPs) can be elicited by one or more biphasic current pulses delivered to the optic nerve (ON) through penetrating electrodes. Multi-channel EEPs recorded from the visual cortex usually contain large stimulus artifacts caused by instantaneous electrotonic current spread through the brain tissue. These stimulus artifacts contaminate the EEP waveform and often make subsequent analysis of the underlying neural responses difficult. This is particularly serious when investigating EEPs in response to electrical stimulation with long duration and multi-pulses. We applied independent component analysis (ICA) to remove these electrical stimulation-induced artifacts during the development of a visual prosthesis. Multi-channel signals were recorded from visual cortices of five rabbits in response to ON electrical stimulation with various stimulus parameters. ON action potentials were then blocked by lidocaine in order to acquire cortical potentials only including stimulus artifacts. Correlation analysis of reconstructed artifacts by ICA and artifacts recorded after blocking the ON indicates successful removal of artifacts from electrical stimulation by the ICA method. This technique has potential applications in studies designed to optimize the electrical stimulation parameters used by visual prostheses.

  7. Transcutaneous electrical nerve stimulation (TENS) improves the diabetic cytopathy (DCP) via up-regulation of CGRP and cAMP.

    PubMed

    Ding, Liucheng; Song, Tao; Yi, Chaoran; Huang, Yi; Yu, Wen; Ling, Lin; Dai, Yutian; Wei, Zhongqing

    2013-01-01

    The objective of this study was to investigate the effects and mechanism of Transcutaneous Electrical Nerve Stimulation (TENS) on the diabetic cytopathy (DCP) in the diabetic bladder. A total of 45 rats were randomly divided into diabetes mellitus (DM)/TENS group (n=15), DM group (n=15) and control group (n=15). The rats in the DM/TENS and TENS groups were electronically stimulated (stimulating parameters: intensity-31 V, frequency-31 Hz, and duration of stimulation of 15 min) for three weeks. Bladder histology, urodynamics and contractile responses to field stimulation and carbachol were determined. The expression of calcitonin gene-related peptide (CGRP) was analyzed by RT-PCR and Western blotting. The results showed that contractile responses of the DM rats were ameliorated after 3 weeks of TENS. Furthermore, TENS significantly increased bladder wet weight, volume threshold for micturition and reduced PVR, V% and cAMP content of the bladder. The mRNA and protein levels of CGRP in dorsal root ganglion (DRG) in the DM/TENS group were higher than those in the DM group. TENS also significantly up-regulated the cAMP content in the bladder body and base compared with diabetic rats. We conclude that TENS can significantly improve the urine contractility and ameliorate the feeling of bladder fullness in DM rats possibly via up-regulation of cAMP and CGRP in DRG.

  8. The parameters of transcutaneous electrical nerve stimulation are critical to its regenerative effects when applied just after a sciatic crush lesion in mice.

    PubMed

    Cavalcante Miranda de Assis, Diana; Martins Lima, Êmyle; Teixeira Goes, Bruno; Zugaib Cavalcanti, João; Barbosa Paixão, Alaí; Vannier-Santos, Marcos André; Martinez, Ana Maria Blanco; Baptista, Abrahão Fontes

    2014-01-01

    We investigated the effect of two frequencies of transcutaneous electrical nerve stimulation (TENS) applied immediately after lesion on peripheral nerve regeneration after a mouse sciatic crush injury. The animals were anesthetized and subjected to crushing of the right sciatic nerve and then separated into three groups: nontreated, Low-TENS (4 Hz), and High-TENS (100 Hz). The animals of Low- and High-TENS groups were stimulated for 2 h immediately after the surgical procedure, while the nontreated group was only positioned for the same period. After five weeks the animals were euthanized, and the nerves dissected bilaterally for histological and histomorphometric analysis. Histological assessment by light and electron microscopy showed that High-TENS and nontreated nerves had a similar profile, with extensive signs of degeneration. Conversely, Low-TENS led to increased regeneration, displaying histological aspects similar to control nerves. High-TENS also led to decreased density of fibers in the range of 6-12 μm diameter and decreased fiber diameter and myelin area in the range of 0-2 μm diameter. These findings suggest that High-TENS applied just after a peripheral nerve crush may be deleterious for regeneration, whereas Low-TENS may increase nerve regeneration capacity.

  9. Release of somatostatin and its role in the mediation of the anti-inflammatory effect induced by antidromic stimulation of sensory fibres of rat sciatic nerve

    PubMed Central

    Szolcsányi, János; Helyes, Zsuzsanna; Oroszi, Gábor; Németh, József; Pintér, Erika

    1998-01-01

    The effect of antidromic stimulation of the sensory fibres of the sciatic nerve on inflammatory plasma extravasation in various tissues and on cutaneous vasodilatation elicited in distant parts of the body was investigated in rats pretreated with guanethidine (8 mg kg−1, i.p.) and pipecuronium (200 μg kg−1, i.v.).Antidromic sciatic nerve stimulation with C-fibre strength (20 V, 0.5 ms) at 5 Hz for 5 min elicited neurogenic inflammation in the innervated area and inhibited by 50.3±4.67% the development of a subsequent plasma extravasation in response to similar stimulation of the contralateral sciatic nerve. Stimulation at 0.5 Hz for 1 h also evoked local plasma extravasation and inhibited the carrageenin-induced (1%, 100 μl s.c.) cutaneous inflammation by 38.5±10.0% in the contralateral paw. Excitation at 0.1 Hz for 4 h elicited no local plasma extravasation in the stimulated hindleg but still reduced the carrageenin-induced oedema by 52.1±9.7% in the paw on the contralateral side.Plasma extravasation in the knee joint in response to carrageenin (2%, 200 μl intra-articular injection) was diminished by 46.1±12.69% and 40.9±4.93% when the sciatic nerve was stimulated in the contralateral leg at 0.5 Hz for 1 h or 0.1 Hz for 4 h, respectively.Stimulation of the peripheral stump of the left vagal nerve (20 V, 1 ms, 8 Hz, 10 min) elicited plasma extravasation in the trachea, oesophagus and mediastinal connective tissue in rats pretreated with atropine (2 mg kg−1, i.v.), guanethidine (8 mg kg−1, i.p.) and pipecuronium (200 μg kg−1, i.v.). These responses were inhibited by 37.8±5.1%, 49.7±9.9% and 37.6±4.2%, respectively by antidromic sciatic nerve excitation (5 Hz, 5 min) applied 5 min earlier.Pretreatment with polyclonal somatostatin antiserum (0.5 ml/rat, i.v.) or the selective somatostatin depleting agent cysteamine (280 mg kg−1, s.c.) prevented the anti-inflammatory effect of

  10. A computational study to evaluate the activation pattern of nerve fibers in response to interferential currents stimulation.

    PubMed

    Agharezaee, Mahsa; Mahnam, Amin

    2015-08-01

    Interferential current (IFC) is one of the most popular electrical currents used in electrotherapy. However, there have been limited studies investigating how this stimulation affects the nerve fibers. The aim of this computational study was to evaluate the temporal and spatial patterns of fiber activation in IFC therapy for different modulation and carrier frequencies. The interferential currents were applied by two pairs of point electrodes perpendicular to each other in an infinite homogeneous medium, and a model of myelinated nerve fibers was implemented in NEURON to study the neural response. The activation thresholds for different positions of the fiber and the resultant firing patterns were evaluated. The results suggest that the fibers may fire continuously or in bursts, with frequencies equal or higher than the modulation frequency, or may be blocked, based on their position relative to the electrodes, the modulation frequency and the stimulus strength. The results confirm traditional belief about the role of the modulation frequency in firing frequency of nerve fibers and describe a possible mechanism for less sensation of pain, due to blockage of the fibers by the high-frequency nature of the interferential currents.

  11. Guidance of Block Needle Insertion by Electrical Nerve Stimulation: A Pilot Study of the Resulting Distribution of Injected Solution in Dogs

    PubMed Central

    Rigaud, Marcel; Filip, Patrick; Lirk, Philipp; Fuchs, Andreas; Gemes, Geza; Hogan, Quinn

    2009-01-01

    Background Little is known regarding the final needle tip location when various intensities of nerve stimulation are used to guide block needle insertion. Therefore, in control and hyperglycemic dogs, the authors examined whether lower-intensity stimulation results in injection closer to the sciatic nerve than higher-threshold stimulation. Methods During anesthesia, the sciatic nerve was approached with an insulated nerve block needle emitting either 1 mA (high-current group, n = 9) or 0.5 mA (low-current group, n = 9 in control dogs and n = 6 in hyperglycemic dogs). After positioning to obtain a distal motor response, the lowest current producing a response was identified, and ink (0.5 ml) was injected. Frozen sections of the tissue revealed whether the ink was in contact with the epineurium of the nerve, distant to it, or within it. Results In control dogs, the patterns of distribution using high-threshold (final current 0.99 ± 0.03 mA, mean ± SD) and low-threshold (final current 0.33 ± 0.08 mA) stimulation equally showed ink that was in contact with the epineurium or distant to it. One needle placement in the high-threshold group resulted in intraneural injection. In hyperglycemic dogs, all needle insertions used a low-threshold technique (n = 6, final threshold 0.35 ± 0.08 mA), and all resulted in intraneural injections. Conclusions In normal dogs, current stimulation levels in the range of 0.33–1.0 mA result in needle placement comparably close to the sciatic nerve but do not correlate with distance from the target nerve. In this experimental design, low-threshold electrical stimulation does not offer satisfactory protection against intraneural injection in the presence of hyperglycemia. PMID:18719445

  12. Repetitive magnetic stimulation induces plasticity of inhibitory synapses

    PubMed Central

    Lenz, Maximilian; Galanis, Christos; Müller-Dahlhaus, Florian; Opitz, Alexander; Wierenga, Corette J.; Szabó, Gábor; Ziemann, Ulf; Deller, Thomas; Funke, Klaus; Vlachos, Andreas

    2016-01-01

    Repetitive transcranial magnetic stimulation (rTMS) is used as a therapeutic tool in neurology and psychiatry. While repetitive magnetic stimulation (rMS) has been shown to induce plasticity of excitatory synapses, it is unclear whether rMS can also modify structural and functional properties of inhibitory inputs. Here we employed 10-Hz rMS of entorhinohippocampal slice cultures to study plasticity of inhibitory neurotransmission on CA1 pyramidal neurons. Our experiments reveal a rMS-induced reduction in GABAergic synaptic strength (2–4 h after stimulation), which is Ca2+-dependent and accompanied by the remodelling of postsynaptic gephyrin scaffolds. Furthermore, we present evidence that 10-Hz rMS predominantly acts on dendritic, but not somatic inhibition. Consistent with this finding, a reduction in clustered gephyrin is detected in CA1 stratum radiatum of rTMS-treated anaesthetized mice. These results disclose that rTMS induces coordinated Ca2+-dependent structural and functional changes of specific inhibitory postsynapses on principal neurons. PMID:26743822

  13. Normative Values for Intertrial Variability of Motor Responses to Nerve Root and Transcranial Stimulation: A Condition for Follow-Up Studies in Individual Subjects

    PubMed Central

    Malucchi, Simona; Capobianco, Marco; Sperli, Francesca

    2016-01-01

    Objective Intertrial variability (ITV) of motor responses to peripheral (CMAP) and transcranial (MEP) stimulation prevents their use in follow-up studies. Our purpose was to develop strategies to reduce and measure CMAP and MEP ITV to guide long-term monitoring of conduction slowing and conduction failure of peripheral and central motor pathway in the individual patient. Methods Maximal compound muscle action potentials to High Voltage Electrical Stimulation (HVES) of lumbo-sacral nerve roots (r-CMAP) and activated, averaged motor evoked potentials (MEPs) to Transcranial Magnetic Stimulation (TMS) using double cone coil were recorded from 10 proximal and distal muscle districts of lower limbs. The procedure was repeated twice, 1–2 days apart, in 30 subjects, including healthy volunteers and clinically stable multiple sclerosis patients, using constant stimulating and recording sites and adopting a standardized procedure of voluntary activation. ITV for latency and area indexes and for the ratio between MEP and r-CMAP areas (a-Ratio) was expressed as Relative Intertrial Variation (RIV, 5th-95th percentile). As an inverse correlation between the size of area and ITV was found, raw ITV values were normalized as a function of area to make them comparable with one another. Results All RIV values for latencies were significantly below the optimum threshold of ± 10%, with the exception of r-CMAP latencies recorded from Vastus Lateralis muscle. RIVs for a-Ratio, the most important index of central conduction failure, ranged from a maximum of -25.3% to +32.2% (Vastus Medialis) to a minimum of -15.0% to + 17.4% (Flexor Hallucis Brevis). Conclusions The described procedure represents an effort to lower as much as possible variability of motor responses in serial recording; the reported ITV normative values are the necessary premise to detect significant changes of motor conduction slowing and failure in the individual patient in follow-up studies. PMID:27182973

  14. Subsurface optical stimulation of the rat prostate nerves using continuous-wave near-infrared laser radiation

    NASA Astrophysics Data System (ADS)

    Tozburun, Serhat; Lagoda, Gwen A.; Burnett, Arthur L.; Fried, Nathaniel M.

    2012-02-01

    Successful identification and preservation of the cavernous nerves (CN), which are responsible for sexual function, during prostate cancer surgery, will require subsurface detection of the CN beneath a thin fascia layer. This study explores optical nerve stimulation (ONS) in the rat with a fascia layer placed over the CN. Two near-IR diode lasers (1455 nm and 1550 nm lasers) were used to stimulate the CN in CW mode with a 1-mm-diameter spot in 8 rats. The 1455 nm wavelength provides an optical penetration depth (OPD) of ~350 μm, while 1550 nm provides an OPD of ~1000 μm (~3 times deeper than 1455 nm and 1870 nm wavelengths previously tested). Fascia layers with thicknesses of 85 - 600 μm were placed over the CN. Successful ONS was confirmed by an intracavernous pressure (ICP) response in the rat penis at 1455 nm through fascia 110 μm thick and at 1550 nm through fascia 450 μm thick. Higher incident laser power was necessary and weaker and slower ICP responses were observed as fascia thickness was increased. Subsurface ONS of the rat CN at a depth of 450 μm using a 1550 nm laser is feasible.

  15. Species differences in the reflex effects of lingual afferent nerve stimulation on lip blood flow and arterial pressure.

    PubMed

    Koeda, S; Yasuda, M; Izumi, H

    2003-11-01

    We evoked changes in lower lip blood flow and systemic arterial blood pressure by electrically stimulating the central cut end of the lingual nerve in artificially ventilated, urethane-anesthetized, cervically vago-sympathectomized cats, rats, rabbits, and guinea pig. The systemic arterial blood pressure changes were species-dependent: increases in rat, consistent decreases in rabbit and guinea pig, and variable among individuals in cat. In cat and rabbit, lip blood flow increases, which occurred only ipsilaterally to the stimulated nerve and showed no statistically significant correlation with the systemic arterial blood pressure changes. In rat, the ipsilateral lip blood flow increase was markedly greater than the contralateral one, and although there was a significant correlation between each of them and the systemic arterial blood pressure changes, the ipsilateral increase presumably included an active vasodilatation. In guinea pig, lip blood flow decreased on both sides in proportion to the systemic arterial blood pressure reductions. Thus, species variability exists in the sympathetic-mediated systemic arterial blood pressure changes and parasympathetic-mediated lip blood flow responses themselves, and in the relationship between them. PMID:12920546

  16. Mean circulatory filling pressure during splanchnic nerve stimulation and whole-body hypoxia in the anaesthetized cat.

    PubMed

    Bower, E A; O'Donnell, C P

    1991-01-01

    1. Mean circulatory filling pressure (MCFP) was measured in cats under chloralose anaesthesia by obstruction of blood flow in the pulmonary artery. Pressures in the aorta, hepatic portal vein and right atrium were recorded, and MCFP was estimated from the value at which all three pressures became equal when blood was pumped from aorta to vena cava during circulatory arrest. Simultaneous equality was not attained at MCFP values below 5 mmHg. 2. In cats ventilated by positive pressure after administration of gallamine, MCFP was 9.7 +/- 0.3 mmHg (n = 14). The values of MCFP measured in six cats before and after administration of gallamine did not differ significantly. Change of blood volume altered MCFP linearly over the range 5-21 mmHg. Noradrenaline (7.5 micrograms kg-1 min-1) increased MCFP from 9.3 +/- 0.9 to 16.5 +/- 0.6 mmHg (n = 4), and phentolamine (2 mg kg-1) reduced it to 5.6 +/- 0.3 mmHg (n = 5). 3. Changes in MCFP were evoked at different circulating blood volumes by stimulation of the splanchnic sympathetic nerves and by whole-body hypoxia. Ablation of all splanchnic nerves reduced MCFP from 9.4 +/- 0.5 to 7.1 +/- 0.3 mmHg (n = 5) and stimulation of their distal ends at 10 Hz increased it by 4.1 +/- 0.4 mmHg (n = 4); similar increments were obtained at different blood volumes and initial values of MCFP. 4. Hypoxia increased MCFP by 0.23 mmHg per 1 mmHg fall in arterial oxygen tension below Pa,O2 56 mmHg (r = -0.86; n = 24). Similar increments were obtained at different blood volumes and initial values of MCFP. Ablation of all splanchnic nerves reduced the increments by 60%, and administration of phentolamine abolished them.

  17. Transcranial magnetic stimulation in patients with cerebellar stroke.

    PubMed

    Cruz-Martínez, A; Arpa, J

    1997-01-01

    Conduction time of the central motor pathways (CMCT) by transcranial magnetic stimulation (TMS) was performed within the first two weeks in 7 patients with isolated hemicerebellar lesions after stroke. Cerebellar infarcts were small (< 2 cm in diameter) in 5 patients and no brainstem structure was involved in CT studies. The threshold (3 cases) and CMCT (4 cases) were abnormal or asymmetric by stimulation of the motor cortex contralateral to the impaired hemicerebellum. The follow-up study in 2 patients revealed electrophysiological improvement closely related to clinical cerebellar recovery rate. CMCT was significantly longer by cortex stimulation contralateral to the impaired hemicerebellum than by ipsilateral stimulation. Prolonged CMCT was significantly correlated with the rated severity of cerebellar signs. Increased threshold may be due to depressed facilitating action of the deep cerebellar nuclei on contralateral motor cortex. Abnormal CMCT might result in reduced size and increased dispersion of the efferent volleys. Recovery of electrophysiological results could represent in part true potentially reversible functional deficit. Whichever the pathophysiological mechanisms involved, our results demonstrate that the cerebellum dysfunction plays a role in the abnormalities of CMCT elicited by TMS.

  18. Effect of transcranial magnetic stimulation on force of finger pinch

    NASA Astrophysics Data System (ADS)

    Odagaki, Masato; Fukuda, Hiroshi; Hiwaki, Osamu

    2009-04-01

    Transcranial magnetic stimulation (TMS) is used to explore many aspects of brain function, and to treat neurological disorders. Cortical motor neuronal activation by TMS over the primary motor cortex (M1) produces efferent signals that pass through the corticospinal tracts. Motor-evoked potentials (MEPs) are observed in muscles innervated by the stimulated motor cortex. TMS can cause a silent period (SP) following MEP in voluntary electromyography (EMG). The present study examined the effects of TMS eliciting MEP and SP on the force of pinching using two fingers. Subjects pinched a wooden block with the thumb and index finger. TMS was applied to M1 during the pinch task. EMG of first dorsal interosseous muscles and pinch forces were measured. Force output increased after the TMS, and then oscillated. The results indicated that the motor control system to keep isotonic forces of the muscles participated in the finger pinch was disrupted by the TMS.

  19. Transcutaneous noninvasive vagus nerve stimulation (tVNS) in the treatment of schizophrenia: a bicentric randomized controlled pilot study.

    PubMed

    Hasan, Alkomiet; Wolff-Menzler, Claus; Pfeiffer, Sebastian; Falkai, Peter; Weidinger, Elif; Jobst, Andrea; Hoell, Imke; Malchow, Berend; Yeganeh-Doost, Peyman; Strube, Wolfgang; Quast, Silke; Müller, Norbert; Wobrock, Thomas

    2015-10-01

    Despite many pharmacological and psychosocial treatment options, schizophrenia remains a debilitating disorder. Thus, new treatment strategies rooted in the pathophysiology of the disorder are needed. Recently, vagus nerve stimulation (VNS) has been proposed as a potential treatment option for various neuropsychiatric disorders including schizophrenia. The objective of this study was to investigate for the first time the feasibility, safety and efficacy of transcutaneous VNS in stable schizophrenia. A bicentric randomized, sham-controlled, double-blind trial was conducted from 2010 to 2012. Twenty schizophrenia patients were randomly assigned to one of two treatment groups. The first group (active tVNS) received daily active stimulation of the left auricle for 26 weeks. The second group (sham tVNS) received daily sham stimulation for 12 weeks followed by 14 weeks of active stimulation. Primary outcome was defined as change in the Positive and Negative Symptom Scale total score between baseline and week 12. Various other secondary measures were assessed to investigate safety and efficacy. The intervention was well tolerated with no relevant adverse effects. We could not observe a statistically significant difference in the improvement of schizophrenia psychopathology during the observation period. Neither psychopathological and neurocognitive measures nor safety measures showed significant differences between study groups. Application of tVNS was well tolerated, but did not improve schizophrenia symptoms in our 26-week trial. While unsatisfactory compliance questions the feasibility of patient-controlled neurostimulation in schizophrenia, the overall pattern of symptom change might warrant further investigations in this population.

  20. Nerve growth factor stimulates the hydrolysis of glycosylphosphatidylinositol in PC-12 cells: A mechanism of protein kinase C regulation

    SciTech Connect

    Chan, B.L.; Saltiel, A.R. ); Chao, M.V. )

    1989-03-01

    Treatment of PC-12 pheochromocytoma cells with nerve growth factor (NGF) results in the differentiation of these cells into a sympathetic neuron-like phenotype. Although the initial intracellular signals elicited by NGF remain unknown, some of the cellular effects of NGF are similar to those of other growth factors, such as insulin. The authors have investigated the involvement of a newly identified inositol-containing glycolipid in signal transduction for the actions of NGF. NGF stimulates the rapid generation of a species of diacylglycerol that is labeled with ({sup 3}H)myristate but not with ({sup 3}H)arachidonate. NGF stimulates ({sup 3}H)myristate- or ({sup 32}P)phosphate-labeled phosphatidic acid production over the same time course. Although NGF alone has no effect on the turnover of inositol phospholipids, it does stimulate the hydrolysis of glycosylphosphatidylinositol. The NGF-dependent cleavage of this lipid is accompanied by an increase in the accumulation of its polar head group, an inositol phosphate glycan, which is generated within 30-60 sec of NGF treatment. In an unresponsive PC-12 mutant cell line, neither the diacylglycerol nor inositol phosphate glycan response is detected. A possible role for the NGF-stimulated diacylglycerol is suggested by the inhibition of NGF-dependent c-fos induction by staurosporin, a potent inhibitor of protein kinase C. These results suggest that, like insulin, some of the cellular effects of NGF may be mediated by the phospholipase C-catalyzed hydrolysis of glycosylphosphatidylinositol.

  1. Determination of stimulation focality in heterogeneous head models during transcranial magnetic stimulation (TMS)

    NASA Astrophysics Data System (ADS)

    Lee, Erik; Hadimani, Ravi; Jiles, David

    2015-03-01

    Transcranial Magnetic Stimulation (TMS) is an increasingly popular tool used by both the scientific and medical community to understand and treat the brain. TMS has the potential to help people with a wide range of diseases such as Parkinson's, Alzheimer's, and PTSD, while currently being used to treat people with chronic, drug-resistant depression. Through computer simulations, we are able to see the electric field that TMS induces in anatomical human models, but there is no measure to quantify this electric field in a way that relates to a specific patient undergoing TMS therapy. We propose a way to quantify the focality of the induced electric field in a heterogeneous head model during TMS by relating the surface area of the brain being stimulated to the total volume of the brain being stimulated. This figure would be obtained by conducting finite element analysis (FEA) simulations of TMS therapy on a patient specific head model. Using this figure to assist in TMS therapy will allow clinicians and researchers to more accurately stimulate the desired region of a patient's brain and be more equipped to do comparative studies on the effects of TMS across different patients. This work was funded by the Carver Charitable Trust.

  2. Fixed-site high-frequency transcutaneous electrical nerve stimulation for treatment of chronic low back and lower extremity pain

    PubMed Central

    Gozani, Shai N

    2016-01-01

    Objective The objective of this study was to determine if fixed-site high-frequency transcutaneous electrical nerve stimulation (FS-TENS) is effective in treating chronic low back and lower extremity pain. Background Transcutaneous electrical nerve stimulation is widely used for treatment of chronic pain. General-purpose transcutaneous electrical nerve stimulation devices are designed for stimulation anywhere on the body and often cannot be used while the user is active or sleeping. FS-TENS devices are designed for placement at a pre-determined location, which enables development of a wearable device for use over extended time periods. Methods Study participants with chronic low back and/or lower extremity pain self-administered an FS-TENS device for 60 days. Baseline, 30-, and 60-day follow-up data were obtained through an online questionnaire. The primary outcome measure was the patient global impression of change. Pain intensity and interference were assessed using the Brief Pain Inventory. Changes in use of concomitant pain medications were evaluated with a single-item global self-rating. Results One hundred and thirty participants were enrolled, with 88 completing the 60-day follow-up questionnaire. Most participants (73.9%) were 50 years of age or older. At baseline, low back pain was identified by 85.3%, lower extremity pain by 71.6%, and upper extremity pain by 62.5%. Participants reported widespread pain, at baseline, with a mean of 3.4 (standard deviation 1.1) pain sites. At the 60-day follow-up, 80.7% of participants reported that their chronic pain had improved and they were classified as responders. Baseline characteristics did not differentiate non-responders from responders. There were numerical trends toward reduced pain interference with walking ability and sleep, and greater pain relief in responders. There was a large difference in use of concomitant pain medications, with 80.3% of responders reporting a reduction compared to 11.8% of non

  3. Modulation of Muscle Tone and Sympathovagal Balance in Cervical Dystonia Using Percutaneous Stimulation of the Auricular Vagus Nerve.

    PubMed

    Kampusch, Stefan; Kaniusas, Eugenijus; Széles, Jozsef C

    2015-10-01

    Primary cervical dystonia is characterized by abnormal, involuntary, and sustained contractions of cervical muscles. Current ways of treatment focus on alleviating symptomatic muscle activity. Besides pharmacological treatment, in severe cases patients may receive neuromodulative intervention such as deep brain stimulation. However, these (highly invasive) methods have some major drawbacks. For the first time, percutaneous auricular vagus nerve stimulation (pVNS) was applied in a single case of primary cervical dystonia. Auricular vagus nerve stimulation was already shown to modulate the (autonomous) sympathovagal balance of the body and proved to be an effective treatment in acute and chronic pain, epilepsy, as well as major depression. pVNS effects on cervical dystonia may be hypothesized to rely upon: (i) the alteration of sensory input to the brain, which affects structures involved in the genesis of motoric and nonmotoric dystonic symptoms; and (ii) the alteration of the sympathovagal balance with a sustained impact on involuntary movement control, pain, quality of sleep, and general well-being. The presented data provide experimental evidence that pVNS may be a new alternative and minimally invasive treatment in primary cervical dystonia. One female patient (age 50 years) suffering from therapy refractory cervical dystonia was treated with pVNS over 20 months. Significant improvement in muscle pain, dystonic symptoms, and autonomic regulation as well as a subjective improvement in motility, sleep, and mood were achieved. A subjective improvement in pain recorded by visual analog scale ratings (0-10) was observed from 5.42 to 3.92 (medians). Muscle tone of the mainly affected left and right trapezius muscle in supine position was favorably reduced by about 96%. Significant reduction of muscle tone was also achieved in sitting and standing positions of the patient. Habituation to stimulation leading to reduced stimulation efficiency was observed and

  4. Modulation of Muscle Tone and Sympathovagal Balance in Cervical Dystonia Using Percutaneous Stimulation of the Auricular Vagus Nerve.

    PubMed

    Kampusch, Stefan; Kaniusas, Eugenijus; Széles, Jozsef C

    2015-10-01

    Primary cervical dystonia is characterized by abnormal, involuntary, and sustained contractions of cervical muscles. Current ways of treatment focus on alleviating symptomatic muscle activity. Besides pharmacological treatment, in severe cases patients may receive neuromodulative intervention such as deep brain stimulation. However, these (highly invasive) methods have some major drawbacks. For the first time, percutaneous auricular vagus nerve stimulation (pVNS) was applied in a single case of primary cervical dystonia. Auricular vagus nerve stimulation was already shown to modulate the (autonomous) sympathovagal balance of the body and proved to be an effective treatment in acute and chronic pain, epilepsy, as well as major depression. pVNS effects on cervical dystonia may be hypothesized to rely upon: (i) the alteration of sensory input to the brain, which affects structures involved in the genesis of motoric and nonmotoric dystonic symptoms; and (ii) the alteration of the sympathovagal balance with a sustained impact on involuntary movement control, pain, quality of sleep, and general well-being. The presented data provide experimental evidence that pVNS may be a new alternative and minimally invasive treatment in primary cervical dystonia. One female patient (age 50 years) suffering from therapy refractory cervical dystonia was treated with pVNS over 20 months. Significant improvement in muscle pain, dystonic symptoms, and autonomic regulation as well as a subjective improvement in motility, sleep, and mood were achieved. A subjective improvement in pain recorded by visual analog scale ratings (0-10) was observed from 5.42 to 3.92 (medians). Muscle tone of the mainly affected left and right trapezius muscle in supine position was favorably reduced by about 96%. Significant reduction of muscle tone was also achieved in sitting and standing positions of the patient. Habituation to stimulation leading to reduced stimulation efficiency was observed and

  5. An early granulocyte colony-stimulating factor treatment attenuates neuropathic pain through activation of mu opioid receptors on the injured nerve

    PubMed Central

    Liao, Ming-Feng; Yeh, Shin-Rung; Lo, Ai-Lun; Chao, Po-Kuan; Lee, Yun-Lin; Hung, Yu-Hui; Lu, Kwok-Tung; Ro, Long-Sun

    2016-01-01

    Several studies have shown that the mu opioid receptor (MOR) located in the peripheral nerves can be activated after nerve injury and that it attenuates peripheral nociceptive signals to the spinal dorsal horn. Various cytokines and phosphorylated-p38 (p-p38) activation in the dorsal horn also play an important role in neuropathic pain development. Granulocyte-colony stimulating factor (GCSF) is a growth factor that can stimulate granulocyte formation and has been shown to exert an analgesic effect on neuropathic pain through recruiting opioid-containing leukocytes to the injured nerve. However, the underlying mechanisms are not well understood. Herein, the results of behavior tests in addition to MOR levels in the injured sciatic nerve and the levels of p-p38 and various cytokines in the spinal dorsal horn were studied in vehicle-treated or GCSF-treated chronic constriction injured (CCI) rats at different time points (i.e., 1, 3, and 7 days, respectively) after nerve injury. The results showed that a single early systemic GCSF treatment after nerve injury can up-regulate MORs in the injured nerve, which can decrease peripheral nociceptive signals. Thereafter, those changes suppress the pro-inflammatory cytokine IL-6 but enhance the anti-inflammatory cytokine IL-4, followed by decreases in p-p38 in the dorsal horn, and thus further attenuate neuropathic pain. PMID:27180600

  6. Magnetically Stimulated Release of a Model Drug From a Magnetic Drug Carrier

    NASA Astrophysics Data System (ADS)

    Riley, Tom; Evans, Ben

    The use of particles in the micro and nanometer ranges has become increasingly important as therapeutic tools in medicine. In particular, magnetically-active particles may allow for magnetically-controlled release of drugs at targeted locations. The drugs can be delivered directly to cancerous tumors at desired concentrations. While hydrogel-based microspheres have been commonly proposed for such purposes, there is also a need for a lipophilic magnetic microsphere for delivery of poorly-soluble pharmaceuticals. We have created a well-dispersed suspension of iron oxide nanoparticles in a silicone matrix, and have used the material to manufacture microspheres in sizes ranging from 100nm to 50 microns. Our spheres are stable in aqueous suspensions, yet their silicone matrix is uniquely suited for the transport and delivery of hydrophobic pharmaceuticals. A high concentration of magnetic nanoparticles (50% wt.) enables magnetic localization, magnetic heating (hyperthermia), and magnetic stimulation to trigger drug release. Using fluorescein as a model drug, we use UV-visible spectroscopy to show a slow native release rate of the hydrophobic fluorescein from the spheres. We use these measurements to quantify the loading capacity of the microspheres, and we show results of magnetically-stimulated drug release using a DM100 field applicator (nanoScale Biomagnetics).

  7. Expiratory-modulated laryngeal motoneurons exhibit a hyperpolarization preceding depolarization during superior laryngeal nerve stimulation in the in vivo adult rat.

    PubMed

    Bautista, Tara G; Sun, Qi-Jian; Pilowsky, Paul M

    2012-03-22

    Swallowing requires the sequential activation of tongue, pharyngeal and esophageal muscles to propel the food bolus towards the stomach. Aspiration during swallow is prevented by adduction of the vocal cords during the oropharyngeal phase. Expiratory-modulated laryngeal motoneurons (ELM) exhibit a burst of action potentials during swallows elicited by electrical stimulation of the superior laryngeal nerve (SLN). Here we sought to investigate changes in membrane potential in ELM during superior laryngeal nerve stimulation in the anaesthetised, in vivo adult rat preparation. Intracellular recordings of ELM in the caudal nucleus ambiguus (identified by antidromic activation from the recurrent laryngeal nerve) demonstrated that ELM bursting activity following SLN stimulation is associated with a depolarization that is preceded by a small hyperpolarization. During spontaneous ELM bursts, the preceding hyperpolarization separated the bursting activity from its usual post-inspiratory activity. These findings demonstrate that the in vivo adult rat preparation is suitable for the study of swallow-related activity in laryngeal motoneurons. PMID:22326041

  8. Gustatory responses of the mouse chorda tympani nerve vary based on region of tongue stimulation.

    PubMed

    Dana, Rachel M; McCaughey, Stuart A

    2015-06-01

    Different parts of the mouth vary in their taste responsiveness and gustatory transduction components. However, there have been few attempts to consider regional variation among areas innervated by a single nerve branch or containing only one type of gustatory papilla. Here, we examined whether taste-elicited responses of a single nerve, the chorda tympani (CT), depend on where taste solutions are delivered on the tongue in mice. In experiment 1, multiunit CT responses to NaCl and sucrose were larger if sapid taste solutions were applied to the tongue tip, which contains the anterior-most fungiform papillae, than if they were flowed over fungiform and foliate papillae on the posterior tongue. Further, the epithelial sodium channel (ENaC) blocker amiloride suppressed NaCl responses to a greater degree for the tongue tip. In experiment 2, CT nerve responses were compared between the tongue tip and a region further back that contained only fungiform papillae. NaCl and sucrose solutions applied to posterior fungiform papillae produced smaller responses than did those elicited by the same taste stimuli applied to anterior fungiform papillae on the tongue tip. Amiloride suppressed the response to NaCl delivered to the anterior fungiform but not posterior fungiform papillae. These results indicate that the CT response is tongue-region dependent in the mouse. Furthermore, the spatial location of a fungiform papilla provides important information about its properties, such as whether sodium taste transduction is mediated by amiloride-sensitive ENaCs.

  9. Physical activity modulates nerve plasticity and stimulates repair after Achilles tendon rupture.

    PubMed

    Bring, Daniel K-I; Kreicbergs, Andris; Renstrom, Per A F H; Ackermann, Paul W

    2007-02-01

    In a rat model of tendon rupture using semiquantitative methodology, healing was assessed according to the diameter of newly organized collagen and the occurrence of the sensory neuropeptides (SP, CGRP) in relation to different levels of physical activity. Normally, innervation of the Achilles tendon is confined to the paratenon. After rupture new nerve fibers grow into the tendon proper, but disappear after healing. In a first experiment to establish peak tissue and nerve regeneration after rupture, tendon tissues from freely moving rats were collected consecutively over 16 weeks. A peak increase in organized collagen and nerve ingrowth was observed between week 2 to 4 post rupture. Therefore, in a second experiment week 4 was chosen to assess the effect of physical activity on tendon healing in three groups of rats, that is, wheel running, plaster treated, and freely moving (controls). In the wheel-running group, the diameter of newly organized collagen was 94% ( p = 0.001) greater than that in the plaster-treated group and 48% ( p = 0.02) greater than that in the controls. Inversely, the neuronal occurrence of CGRP in the tendon proper was 57% ( p = 0.02) lower in the wheel-running group than that in the plaster-treated group and 53% ( p = 0.02) lower than that in the controls, suggesting an earlier neuronal in-growth and disappearance in the more active group. Physical activity speeds up tendon healing, which may prove to be linked to accelerated neuronal plasticity.

  10. High voltage pulsed current stimulation of the sciatic nerve in rats: analysis by the SFI

    PubMed Central

    Leoni, Anita Sofia Leite; Mazzer, Nilton; Guirro, Rinaldo Roberto de Jesus; Jatte, Fernanda Guadallini; Chereguini, Paulo Augusto Costa; Monte-Raso, Vanessa Vilela

    2012-01-01

    Objective To analyze the efficiency of high voltage pulsed current (HVPC) with early application in three different sites, in the regeneration of the sciatic nerve in rats submitted to crush injury, the sciatic functional index (SFI) was used to assess the functional recovery. Methods After crushing of the nerve, 57 animals were submitted to cathodal HVPC at frequency of 50Hz and voltage of 100V, 20 minutes per day, 5 days per week. The rats were divided into five groups: control group; ganglion group; ganglion + muscle group; muscle group; and sham group. The SFI was determined weekly for seven weeks, from the preoperative period to the 6th postoperative week. Results Compared with the control group, the results showed a significantly better performance of group 2 for the first 3 weeks; group 3 showed significantly better performance in the third week; and group 4 showed a significantly negative performance during the 4th and 6th weeks. Conclusion Early application of HVPC had a positive effect in the treatment of the spinal cord region and the sciatic nerve root ganglion with a dispersive electrode on the contralateral lumbar region or on the gastrocnemius. However, HVPC had a negative effect in the treatment with an active electrode on the gastrocnemius and a dispersive electrode on the contralateral thigh. Level of evidence II, Prospective comparative study. PMID:24453588

  11. [THE THERAPUETIC USE OF TRANSCRANIAL MAGNETIC STIMULATION IN MAJOR DEPRESSION].

    PubMed

    Németh, Viola Luca; Csifcsák, Gábor; Kincses, Zsigmond Tamás; Janka, Zoltán; Must, Anita

    2016-03-30

    The antidepressive effect of repetitive transcranial magnetic stimulation (rTMS) has been investigated for almost 20 years now. Several studies have been published aiming to identify the exact and reliable parameters leading to the desired therapeutic effect. However, the related literature shows great variability. The current overview aims to provide a comprehensive overview of factors associated with the therapeutic effect of rTMS in major depression. High frequency stimulation of the left dorsolateral prefrontal cortex (DLPFC) for 3-6 weeks leads to mood improvement comparable to the effect of antidepressive medications in 35-40% of patients. Pharmacotherapy resistant patients treated with rTMS reach remission for 3 months on average. Low frequency stimulation of the right DLPFC appears to be similarly effective, though much less investigated so far. In addition to the exact delineation of the stimulation area, treatment outcome is also related to stimulation intensity as well as the number of sessions and impulses. Considering the safety and tolerability aspects of rTMS, it might be a significant therapeutic support for therapy resistant patients. Above this, patients diagnosed with major depression might benefit from the additional positive influence of rTMS improving the effect of antidepressive medication. Based on converging research evidence, the Food and Drug Administration (FDA) agency approved the use of rTMS as a treatment option for therapy resistant major depression in 2008. So far, in Hungary rTMS is primarily considered as a promising tool in research settings only. Hopefully, patients suffering from major depression will increasingly benefit from the positive therapeutic effect of this intervention. PMID:27188001

  12. Magnetic Vestibular Stimulation in Subjects with Unilateral Labyrinthine Disorders

    PubMed Central

    Ward, Bryan K.; Roberts, Dale C.; Della Santina, Charles C.; Carey, John P.; Zee, David S.

    2014-01-01

    We recently discovered that static magnetic fields from high-strength MRI machines induce nystagmus in all normal humans, and that a magneto-hydrodynamic Lorentz force, derived from ionic currents in the endolymph and pushing on the cupula, best explains this effect. Individuals with no labyrinthine function have no nystagmus. The influence of magnetic vestibular stimulation (MVS) in individuals with unilateral deficits in labyrinthine function is unknown and may provide insight into the mechanism of MVS. These individuals should experience MVS, but with a different pattern of nystagmus consistent with their unilateral deficit in labyrinthine function. We recorded eye movements in the static magnetic field of a 7 T MRI machine in nine individuals with unilateral labyrinthine hypofunction, as determined by head impulse testing and vestibular-evoked myogenic potentials (VEMP). Eye movements were recorded using infrared video-oculography. Static head positions were varied in pitch with the body supine, and slow-phase eye velocity (SPV) was assessed. All subjects exhibited predominantly horizontal nystagmus after entering the magnet head-first, lying supine. The SPV direction reversed when entering feet-first. Pitching chin-to-chest caused subjects to reach a null point for horizontal SPV. Right unilateral vestibular hypofunction (UVH) subjects developed slow-phase-up nystagmus and left UVH subjects, slow-phase-down nystagmus. Vertical and torsional components were consistent with superior semicircular canal excitation or inhibition, respectively, of the intact ear. These findings provide compelling support for the hypothesis that MVS is a result of a Lorentz force and suggest that the function of individual structures within the labyrinth can be assessed with MVS. As a novel method of comfortable and sustained labyrinthine stimulation, MVS can provide new insights into vestibular physiology and pathophysiology. PMID:24659983

  13. Effects of vagus nerve stimulation in a patient with temporal lobe epilepsy and Asperger syndrome: case report and review of the literature.

    PubMed

    Warwick, Tanya C; Griffith, James; Reyes, Bernardo; Legesse, Benalfew; Evans, Melanie

    2007-03-01

    Seizures are a common comorbidity of autism and occur in as many as 30% of patients. This case report describes a 23-year-old man diagnosed with both Asperger syndrome and bitemporal epilepsy. The patient had behavioral regression that correlated with worsening of his intractable seizures. He subsequently underwent implantation of a vagus nerve stimulation therapy device for his refractory epilepsy. Both his seizures and his behavior were monitored for 6 months. We describe the efficacy of vagus nerve stimulation therapy in reducing seizure severity as well as improving the behavioral components of his Asperger syndrome. We also review the current literature regarding epilepsy in autistic spectrum disorders.

  14. Transcranial Magnetic Stimulation Measures in Attention-Deficit/Hyperactivity Disorder

    PubMed Central

    WU, STEVE W; GILBERT, DONALD L; SHAHANA, NASRIN; HUDDLESTON, DAVID A; MOSTOFSKY, STEWART H

    2012-01-01

    Children affected by Attention-Deficit/Hyperactivity Disorder have diminished intra-hemispheric inhibition (Short Interval Cortical Inhibition) as measured by Transcranial Magnetic Stimulation. This study’s objective is to determine whether inter-hemispheric inhibition (Ipsilateral Silent Period Latency) correlates with clinical behavioral rating and motor control deficits of affected children. In 114 8–12 year old, right-handed children (age/sex-matched, 50 affected, 64 controls), we performed comprehensive assessments of behavior, motor skills and cognition. Using Transcranial Magnetic Stimulation, we reliably elicited Ipsilateral Silent Period in 54 children (23 affected) - all were on average older than those who had unobtainable measures. Mean Ipsilateral Silent Period latency was 5 milliseconds longer in the affected group (p=0.007). Longer latencies correlated with more severe behavioral symptom scores (r=0.38, p=0.007), particularly hyperactivity (r=0.39, p=0.006), as well as with worse motor ratings on the Physical and Neurological Examination for Soft Signs (r=0.27, p=0.05). Longer latency also correlated with Short Interval Cortical Inhibition (r=0.36, p=0.008). In conclusion, longer Ipsilateral Silent Period latencies suggest interhemispheric inhibitory signaling is slower in affected children. The deficit in this inhibitory measure may underlie developmental, behavioral and motor impairments in children with Attention-Deficit/Hyperactivity Disorder. PMID:22883282

  15. 21 CFR 882.5830 - Implanted diaphragmatic/phrenic nerve stimulator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... which an abnormally low amount of air enters the lungs) caused by brain stem disease, high cervical spinal cord injury, or chronic lung disease. The stimulator consists of an implanted receiver...

  16. 21 CFR 882.5830 - Implanted diaphragmatic/phrenic nerve stimulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... which an abnormally low amount of air enters the lungs) caused by brain stem disease, high cervical spinal cord injury, or chronic lung disease. The stimulator consists of an implanted receiver...

  17. Transcranial magnetic stimulation (TMS) in the treatment of substance addiction

    PubMed Central

    Gorelick, David A.; Zangen, Abraham; George, Mark S.

    2014-01-01

    Transcranial magnetic stimulation (TMS) is a non-invasive method of brain stimulation used to treat a variety of neuropsychiatric disorders, but is still in the early stages of study as addiction treatment. We identified 19 human studies using repetitive TMS (rTMS) to manipulate drug craving or use, which exposed a total of 316 adults to active rTMS. Nine studies involved tobacco, six alcohol, three cocaine, and one methamphetamine. The majority of studies targeted high-frequency (5–20 Hz; expected to stimulate neuronal activity) rTMS pulses to the dorsolateral prefrontal cortex. Only five studies were controlled clinical trials: two of four nicotine trials found decreased cigarette smoking; the cocaine trial found decreased cocaine use. Many aspects of optimal treatment remain unknown, including rTMS parameters, duration of treatment, relationship to cue-induced craving, and concomitant treatment. The mechanisms of rTMS potential therapeutic action in treating addictions are poorly understood, but may involve increased dopamine and glutamate function in corticomesolimbic brain circuits and modulation of neural activity in brain circuits that mediate cognitive processes relevant to addiction, such as response inhibition, selective attention, and reactivity to drug-associated cues. rTMS treatment of addiction must be considered experimental at this time, but appears to have a promising future. PMID:25069523

  18. Electronically Switchable Sham Transcranial Magnetic Stimulation (TMS) System

    PubMed Central

    Hoeft, Fumiko; Wu, Daw-An; Hernandez, Arvel; Glover, Gary H.; Shimojo, Shinsuke

    2008-01-01

    Transcranial magnetic stimulation (TMS) is increasingly being used to demonstrate the causal links between brain and behavior in humans. Further, extensive clinical trials are being conducted to investigate the therapeutic role of TMS in disorders such as depression. Because TMS causes strong peripheral effects such as auditory clicks and muscle twitches, experimental artifacts such as subject bias and placebo effect are clear concerns. Several sham TMS methods have been developed, but none of the techniques allows one to intermix real and sham TMS on a trial-by-trial basis in a double-blind manner. We have developed an attachment that allows fast, automated switching between Standard TMS and two types of control TMS (Sham and Reverse) without movement of the coil or reconfiguration of the setup. We validate the setup by performing mathematical modeling, search-coil and physiological measurements. To see if the stimulus conditions can be blinded, we conduct perceptual discrimination and sensory perception studies. We verify that the physical properties of the stimulus are appropriate, and that successive stimuli do not contaminate each other. We find that the threshold for motor activation is significantly higher for Reversed than for Standard stimulation, and that Sham stimulation entirely fails to activate muscle potentials. Subjects and experimenters perform poorly at discriminating between Sham and Standard TMS with a figure-of-eight coil, and between Reverse and Standard TMS with a circular coil. Our results raise the possibility of utilizing this technique for a wide range of applications. PMID:18398456

  19. Enhanced visual perception with occipital transcranial magnetic stimulation.

    PubMed

    Mulckhuyse, Manon; Kelley, Todd A; Theeuwes, Jan; Walsh, Vincent; Lavie, Nilli

    2011-10-01

    Transcranial magnetic stimulation (TMS) over the occipital pole can produce an illusory percept of a light flash (or 'phosphene'), suggesting an excitatory effect. Whereas previous reported effects produced by single-pulse occipital pole TMS are typically disruptive, here we report the first demonstration of a location-specific facilitatory effect on visual perception in humans. Observers performed a spatial cueing orientation discrimination task. An orientation target was presented in one of two peripheral placeholders. A single pulse below the phosphene threshold applied to the occipital pole 150 or 200 ms before stimulus onset was found to facilitate target discrimination in the contralateral compared with the ipsilateral visual field. At the 150-ms time window contralateral TMS also amplified cueing effects, increasing both facilitation effects for valid cues and interference effects for invalid cues. These results are the first to show location-specific enhanced visual perception with single-pulse occipital pole stimulation prior to stimulus presentation, suggesting that occipital stimulation can enhance the excitability of visual cortex to subsequent perception. PMID:21848918

  20. Electrical stimulation of the aortic depressor nerve in conscious rats overcomes the attenuation of the baroreflex in chronic heart failure.

    PubMed

    Pinto, Tomás O C Teixeira; Lataro, Renata M; Castania, Jaci A; Durand, Marina T; Silva, Carlos A A; Patel, Kaushik P; Fazan, Rubens; Salgado, Helio C

    2016-04-01

    Chronic heart failure (CHF) is characterized by autonomic dysfunction combined with baroreflex attenuation. The hypotensive and bradycardic responses produced by electrical stimulation of the aortic depressor nerve (ADN) were examined in conscious CHF and control male Wistar rats (12-13 wk old). Furthermore, the role of parasympathetic and sympathetic nervous system in mediating the cardiovascular responses to baroreflex activation was evaluated by selective β1-adrenergic and muscarinic receptor antagonists. CHF was induced by myocardial infarction. After 6 wk, the subjects were implanted with electrodes for ADN stimulation. Twenty-four hours later, electrical stimulation of the ADN was applied for 20 s using five different frequencies (5, 15, 30, 60, and 90 Hz), while the arterial pressure was recorded by a catheter implanted into the femoral artery. Electrical stimulation of the ADN elicited progressive and similar hypotensive and bradycardic responses in control (n = 12) and CHF (n = 11) rats, while the hypotensive response was not affected by methylatropine. Nevertheless, the reflex bradycardia was attenuated by methylatropine in control, but not in CHF rats. Atenolol did not affect the hypotensive or bradycardic response in either group. The ADN function was examined under anesthesia through electroneurographic recordings. The arterial pressure-ADN activity relationship was attenuated in CHF rats. In conclusion, despite the attenuation of baroreceptor function in CHF rats, the electrical stimulation of the ADN elicited a stimulus-dependent hypotension and bradycardia of similar magnitude as observed in control rats. Therefore, electrical activation of the aortic baroreflex overcomes both the attenuation of parasympathetic function and the sympathetic overdrive.

  1. Increasing the oscillation frequency of strong magnetic fields above 101 kHz significantly raises peripheral nerve excitation thresholds

    PubMed Central

    Weinberg, Irving N.; Stepanov, Pavel Y.; Fricke, Stanley T.; Probst, Roland; Urdaneta, Mario; Warnow, Daniel; Sanders, Howard; Glidden, Steven C.; McMillan, Alan; Starewicz, Piotr M.; Reilly, J. Patrick

    2012-01-01

    Purpose: A time-varying magnetic field can cause unpleasant peripheral nerve stimulation (PNS) when the maximum excursion of the magnetic field (ΔB) is above a frequency-dependent threshold level [P. Mansfield and P. R. Harvey, Magn. Reson. Med. 29, 746–758 (1993)]. Clinical and research magnetic resonance imaging (MRI) gradient systems have been designed to avoid such bioeffects by adhering to regulations and guidelines established on the basis of clinical trials. Those trials, generally employing sinusoidal waveforms, tested human responses to magnetic fields at frequencies between 0.5 and 10 kHz [W. Irnich and F. Schmitt, Magn. Reson. Med. 33, 619–623 (1995), T. F. Budinger et al., J. Comput. Assist. Tomogr. 15, 909–914 (1991), and D. J. Schaefer et al., J. Magn. Reson. Imaging 12, 20–29 (2000)]. PNS thresholds for frequencies higher than 10 kHz had been extrapolated, using physiological models [J. P. Reilly et al., IEEE Trans. Biomed. Eng. BME-32(12), 1001–1011 (1985)]. The present study provides experimental data on human PNS thresholds to oscillating magnetic field stimulation from 2 to 183 kHz. Sinusoidal waveforms were employed for several reasons: (1) to facilitate comparison with earlier reports that used sine waves, (2) because prior designers of fast gradient hardware for generalized waveforms (e.g., including trapezoidal pulses) have employed quarter-sine-wave resonant circuits to reduce the rise- and fall-times of pulse waveforms, and (3) because sinusoids are often used in fast pulse sequences (e.g., spiral scans) [S. Nowak, U.S. patent 5,245,287 (14 September 1993) and K. F. King and D. J. Schaefer, J. Magn. Reson. Imaging 12, 164–170 (2000)]. Methods: An IRB-approved prospective clinical trial was performed, involving 26 adults, in which one wrist was exposed to decaying sinusoidal magnetic field pulses at frequencies from 2 to 183 kHz and amplitudes up to 0.4 T. Sham exposures (i.e., with no magnetic fields) were applied to all

  2. Inhibition of histamine-induced bronchoconstriction in Guinea pig and Swine by pulsed electrical vagus nerve stimulation.

    PubMed

    Hoffmann, Thomas J; Mendez, Steven; Staats, Peter; Emala, Charles W; Guo, Puyun

    2009-10-01

    Objective. Smooth muscle help regulate the diameter of the airways and their constriction can contribute to the pathology of acute asthma attacks. This study sought to determine if applying a specific electrical signal to the vagus nerve (VN) could minimize histamine-induced bronchoconstriction. Methods. Sixteen guinea pigs and three swine were anesthetized and had bipolar electrodes positioned on the cervical VNs. After the animals stabilized, i.v. histamine was titrated to elicit a moderate 2-4 cm H(2) O increase in pulmonary inflation pressure (Ppi). Histamine was then dosed with or without concurrent low voltage VN stimulation. Results. The peak change in Ppi following a histamine challenge was reduced in the guinea pig by VN stimulation (3.4 ± 0.4 vs. 2.1 ± 0.2 cm H(2) O, p < 0.001). The results were confirmed in a limited study in swine and indicate VN treatment is applicable to larger animals. Conclusion. This study suggests that VN stimulation can reduce bronchoconstriction and may prove useful as a rescue therapy in the treatment of acute asthma.

  3. High permeability cores to optimize the stimulation of deeply located brain regions using transcranial magnetic stimulation

    NASA Astrophysics Data System (ADS)

    Salvador, R.; Miranda, P. C.; Roth, Y.; Zangen, A.

    2009-05-01

    Efficient stimulation of deeply located brain regions with transcranial magnetic stimulation (TMS) poses many challenges, arising from the fact that the induced field decays rapidly and becomes less focal with depth. We propose a new method to improve the efficiency of TMS of deep brain regions that combines high permeability cores, to increase focality and field intensity, with a coil specifically designed to induce a field that decays slowly with increasing depth. The performance of the proposed design was investigated using the finite element method to determine the total electric field induced by this coil/core arrangement on a realistically shaped homogeneous head model. The calculations show that the inclusion of the cores increases the field's magnitude by as much as 25% while also decreasing the field's decay with depth along specific directions. The focality, as measured by the area where the field's norm is greater than 1/\\sqrt 2 of its maximum value, is also improved by as much as 15% with some core arrangements. The coil's inductance is not significantly increased by the cores. These results show that the presence of the cores might make this specially designed coil even more suited for the effective stimulation of deep brain regions.

  4. Efficacy of Transcutaneous Electric Nerve Stimulation on Parotid Saliva Flow Rate in Relation to Age and Gender

    PubMed Central

    Dhillon, Manu; M Raju, Srinivasa; S Mohan, Raviprakash; Tomar, Divya

    2016-01-01

    Statement of the Problem Treatment with salivary substitutes and stimulation of salivary flow by either mechanical or pharmacologic methods has side effects and only provides symptomatic relief but no long-lasting results. Purpose To assess the effectiveness of extraoral transcutaneous electric nerve stimulation (TENS) as a mean of stimulating salivary function in healthy adult subjects; as well as to determine the gender and age-dependent changes in salivary flow rates of unstimulated and stimulated parotid saliva. Materials and Method Hundred patients were divided into two groups; Group I aged 20-40 and Group II aged ≥ 60 years. The TENS electrode pads were externally placed on the skin overlying the parotid glands. Unstimulated and stimulated parotid saliva was collected for 5 minutes each by using standardized collection techniques. Results Eighty seven of 100 subjects demonstrated increased salivary flow when stimulated via the TENS unit. Ten experienced no increase and 3 experienced a decrease. The mean unstimulated salivary flow rate was 0.01872 ml/min in Group I and 0.0088 ml/min in Group II. The mean stimulated salivary flow rate was 0.03084 ml/min (SD= 0.01248) in Group I, and 0.01556 ml/min (SD 0.0101) in Group II. After stimulation, the amount of salivary flow increased significantly in both groups (p< 0.001). Statistical comparison of the two groups revealed them to be significantly different (p< 0.001), with Group I producing more saliva. Gender-wise, no statistically significant difference was seen among the subjects in Group I (p = 0.148), and those in Group II (p= 0.448). Out of 12 subjects with 0 baseline flows, 7 continued to have no flow. Five subjects observed side effects, although minimal and transient. Conclusion The TENS unit was effective in increasing parotid gland salivary flow in healthy subjects. There was age-related but no gender-related variability in parotid salivary flow rate.

  5. Efficacy of Transcutaneous Electric Nerve Stimulation on Parotid Saliva Flow Rate in Relation to Age and Gender

    PubMed Central

    Dhillon, Manu; M Raju, Srinivasa; S Mohan, Raviprakash; Tomar, Divya

    2016-01-01

    Statement of the Problem Treatment with salivary substitutes and stimulation of salivary flow by either mechanical or pharmacologic methods has side effects and only provides symptomatic relief but no long-lasting results. Purpose To assess the effectiveness of extraoral transcutaneous electric nerve stimulation (TENS) as a mean of stimulating salivary function in healthy adult subjects; as well as to determine the gender and age-dependent changes in salivary flow rates of unstimulated and stimulated parotid saliva. Materials and Method Hundred patients were divided into two groups; Group I aged 20-40 and Group II aged ≥ 60 years. The TENS electrode pads were externally placed on the skin overlying the parotid glands. Unstimulated and stimulated parotid saliva was collected for 5 minutes each by using standardized collection techniques. Results Eighty seven of 100 subjects demonstrated increased salivary flow when stimulated via the TENS unit. Ten experienced no increase and 3 experienced a decrease. The mean unstimulated salivary flow rate was 0.01872 ml/min in Group I and 0.0088 ml/min in Group II. The mean stimulated salivary flow rate was 0.03084 ml/min (SD= 0.01248) in Group I, and 0.01556 ml/min (SD 0.0101) in Group II. After stimulation, the amount of salivary flow increased significantly in both groups (p< 0.001). Statistical comparison of the two groups revealed them to be significantly different (p< 0.001), with Group I producing more saliva. Gender-wise, no statistically significant difference was seen among the subjects in Group I (p = 0.148), and those in Group II (p= 0.448). Out of 12 subjects with 0 baseline flows, 7 continued to have no flow. Five subjects observed side effects, although minimal and transient. Conclusion The TENS unit was effective in increasing parotid gland salivary flow in healthy subjects. There was age-related but no gender-related variability in parotid salivary flow rate. PMID:27602390

  6. Vestibular and pulse-related modulation of skin sympathetic nerve activity during sinusoidal galvanic vestibular stimulation in human subjects.

    PubMed

    James, Cheree; Stathis, Alexandra; Macefield, Vaughan G

    2010-04-01

    We have previously shown that sinusoidal galvanic vestibular stimulation (sGVS), a means of a selectively modulating vestibular afferent input without affecting other inputs, can cause partial entrainment of muscle sympathetic nerve activity (MSNA). Given that motion sickness causes sweating and pallor, we tested the hypothesis that sGVS also entrains skin sympathetic nerve activity (SSNA), but that the optimal frequencies are closer to those associated with slow postural changes (0.2 Hz). SSNA was recorded via tungsten microelectrodes inserted into the common peroneal nerve in 11 awake-seated subjects. Bipolar binaural sinusoidal GVS (+/-2 mA, 200 cycles) was applied to the mastoid processes at frequencies of 0.2, 0.5, 0.8, 1.1, 1.4, 1.7 and 2.0 Hz. All subjects reported strong postural illusions of 'rocking in a boat' or 'swaying in a hammock'. Sinusoidal GVS caused a marked entrainment of SSNA at all frequencies. Measured as the modulation index, vestibular modulation ranged from 81.5 +/- 4.0% at 0.2 Hz to 76.6 +/- 3.6% at 1.7 Hz; it was significantly weaker at 2.0 Hz (63.2 +/- 5.4%). Interestingly, pulse-related modulation of SSNA, which is normally weak, increased significantly during sGVS but was stronger at 0.8 Hz (86.2 +/- 2.0%) than at 0.2 Hz (69.3 +/- 8.3%), the opposite of the pattern seen with vestibular modulation of MSNA. We conclude that vestibular inputs can entrain the firing of cutaneous sympathetic neurones and increase their normally weak pulse-related rhythmicity.

  7. Activation of the central nervous system induced by micro-magnetic stimulation

    PubMed Central

    Park, Hyun-Joo; Bonmassar, Giorgio; Kaltenbach, James A.; Machado, Andre G.; Manzoor, Nauman F.; Gale, John T.

    2013-01-01

    Electrical and transcranial magnetic stimulation have proven to be therapeutically beneficial for patients suffering from neurological disorders. Moreover, these stimulation technologies have provided invaluable tools for investigating nervous system functions. Despite this success, these technologies have technical and practical limitations impeding the maximization of their full clinical and preclinical potential. Recently, micro-magnetic stimulation, which may offer advantages over electrical and transcranial magnetic stimulation, has proven effective in activating the neuronal circuitry of the retina in vitro. Here we demonstrate that this technology is also capable of activating neuronal circuitry on a systems level using an in vivo preparation. Specifically, the application of micro-magnetic fields to the dorsal cochlear nucleus activates inferior colliculus neurons. Additionally, we demonstrate the efficacy and characteristics of activation using different magnetic stimulation parameters. These findings provide a rationale for further exploration of micro-magnetic stimulation as a prospective tool for clinical and preclinical applications. PMID:24030203

  8. Vagus Nerve Stimulation Alters Phase Synchrony of the Anterior Cingulate Cortex and Facilitates Decision Making in Rats

    PubMed Central

    Cao, Bing; Wang, Jun; Shahed, Mahadi; Jelfs, Beth; Chan, Rosa H. M.; Li, Ying

    2016-01-01

    Vagus nerve stimulation (VNS) can enhance memory and cognitive functions in both rats and humans. Studies have shown that VNS influenced decision-making in epileptic patients. However, the sites of action involved in the cognitive-enhancement are poorly understood. By employing a conscious rat model equipped with vagus nerve cuff electrode, we assess the role of chronic VNS on decision-making in rat gambling task (RGT). Simultaneous multichannel-recordings offer an ideal setup to test the hypothesis that VNS may induce alterations of in both spike-field-coherence and synchronization of theta oscillations across brain areas in the anterior cingulate cortex (ACC) and basolateral amygdala (BLA). Daily VNS, administered immediately following training sessions of RGT, caused an increase in ‘good decision-maker’ rats. Neural spikes in the ACC became synchronized with the ongoing theta oscillations of local field potential (LFP) in BLA following VNS. Moreover, cross-correlation analysis revealed synchronization between the ACC and BLA. Our results provide specific evidence that VNS facilitates decision-making and unveils several important roles for VNS in regulating LFP and spike phases, as well as enhancing spike-phase coherence between key brain areas involved in cognitive performance. These data may serve to provide fundamental notions regarding neurophysiological biomarkers for therapeutic VNS in cognitive impairment. PMID:27731403

  9. Effects of transcutaneous electrical nerve stimulation (TENS) on self-efficacy and mood in elderly with mild cognitive impairment.

    PubMed

    Luijpen, Marijn W; Swaab, Dick F; Sergeant, Joseph A; Scherder, Erik J A

    2004-09-01

    In previous studies, transcutaneous electrical nerve stimulation (TENS) has been applied to patients with either Alzheimer's disease (AD) or incipient dementia, resulting in an enhancement in memory and verbal fluency. Moreover, affective behavior was shown to improve. Based on the positive effects of TENS in AD, it was hypothesized that TENS would improve self-efficacy in nondemented elderly with mild cognitive impairment (MCI) who live in a residential home. Four outcome measures, that is, a Dutch translation of the General Self-Efficacy Scale (Algemene Competentie Schaal), the Groninger Activity Restriction Scale, the Philadelphia Geriatric Center Morale Scale, and the Geriatric Depression Scale, were administered. Overall, the results suggest that the experimental group showed a mild improvement in self-efficacy and mood. In contrast, the placebo group showed a considerable reduction in self-efficacy and an increase in depression. Limitations of the present study and suggestions for future research are discussed.

  10. Subcutaneous Peripheral Nerve Field Stimulation for the Treatment of Chronic Back Pain: Patient Selection and Technical Aspects.

    PubMed

    Winkelmueller, Matthias; Kolodziej, Malgorzata Anna; Welke, Wolfgang; Koulousakis, Athanasios; Martinez, Ramon

    2016-01-01

    A wide variety of therapeutic options are available for the treatment of chronic back pain, a very common condition in Western countries with high related social and economic costs. Nevertheless, it is not always possible to achieve adequate long-term pain relief in spite of intensive analgesic therapies. Subcutaneous peripheral nerve field stimulation (sPNFS) is a newly approved neuromodulative treatment for back pain. In previously reported case series, it has provided encouraging results on long-term pain relief, improvement in quality of life, and a reduced need for analgesic drugs. Although the surgical technique is simple, there is neither consensus for patient management nor a standardized procedure for the implantation procedure. After consideration of our personal experience and the published literature, a basic recommendation has now been developed. This represents the first step toward planning prospective studies and standardization of this treatment and will permit comparison of this technique and the results with sPNFS.

  11. Interaction of transcutaneous spinal stimulation and transcranial magnetic stimulation in human leg muscles.

    PubMed

    Roy, François D; Bosgra, Dillen; Stein, Richard B

    2014-06-01

    Transcutaneous spinal stimulation is a noninvasive method that can activate dorsal and/or ventral roots depending on the location and intensity of stimulation. Reflex root-evoked potentials (REPs) were studied in muscles that traditionally evoke large (soleus) and small H-reflexes (tibialis anterior), as well as muscles where H-reflexes are difficult to study (hamstrings). This study characterizes the interaction of the REP and the motor-evoked potential (MEP). Transcranial magnetic stimulation (TMS) delivered 11-25 ms before spinal stimulation resulted in more than linear summation of the two responses. Because of overlap, the modulation was quantified after subtracting the contribution of the conditioning MEP or REP. At rest, the mean-rectified soleus response was facilitated by up to ~250 μV (21-times the MEP or 161% of the REP). The increases were more reliable during a voluntary contraction (up to ~300 μV, 517% of the MEP or 181% of the REP). At the 13-ms interval, the mean-rectified response in the pre-contracted hamstrings was increased by 227% of the MEP or 300% of the REP. In some subjects, TMS could also eliminate the post-activation depression produced using two spinal stimuli, confirming that the interaction can extend to presynaptic spinal neurons. The spatiotemporal facilitation in tibialis anterior was not significant. However, the large MEP was facilitated when the spinal stimulus preceded TMS by 100-150 ms, presumably because of rebound excitation. These strong interactions may be important for inducing motor plasticity and improved training procedures for recovery after neurological damage. PMID:24531641

  12. Transcranial magnetic stimulation in schizophrenia: the contribution of neuroimaging.

    PubMed

    Du, Zhong-de; Wang, R; Prakash, Ravi; Chaudhury, S; Dayananda, G

    2012-01-01

    At the most basic level, the Transcranial Magnetic Stimulation(TMS) is a neuro-scientific tool that exerts its action by influencing the neo-cortical functions. However, in-spite of so many well-evidenced roles of TMS in neuropsychiatric conditions, its exact mechanism of action remains to be known. More intriguing are its therapeutic effects in Schizophrenia at the Cerebral-level. In this review, we adopt a neuro-imaging approach for this exploration. We review the present literature for the studies in Schizophrenia which have used a combination of rTMS with 1) Electroenchephalogram (EEG) 2)The functional Magnetic Resonance Imaging (fMRI) and the 3) Positron Emission Tomography (PET)/ Single-Photon Emission Computed Tomography. The TMS-EEG combination provides direct effects of TMS on the electro- magnetic field (EMF) of brain. The TMS-fMRI/PET/SPECT combinations are very effective in exploring the functional connectivity in brains of Schizophrenia patients as well as in performing rTMS guided neuro-navigation. Our review suggests that TMS combined with other neuroimaging modalities are needed for a better clarification of its neural actions. PMID:23409741