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Sample records for afferent electrical stimulation

  1. Physiological recruitment of motor units by high-frequency electrical stimulation of afferent pathways.

    PubMed

    Dideriksen, Jakob L; Muceli, Silvia; Dosen, Strahinja; Laine, Christopher M; Farina, Dario

    2015-02-01

    Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation, but electrically evoked muscle activation is in several ways different from voluntary muscle contractions. These differences lead to challenges in the use of NMES for restoring muscle function. We investigated the use of low-current, high-frequency nerve stimulation to activate the muscle via the spinal motoneuron (MN) pool to achieve more natural activation patterns. Using a novel stimulation protocol, the H-reflex responses to individual stimuli in a train of stimulation pulses at 100 Hz were reliably estimated with surface EMG during low-level contractions. Furthermore, single motor unit recruitment by afferent stimulation was analyzed with intramuscular EMG. The results showed that substantially elevated H-reflex responses were obtained during 100-Hz stimulation with respect to a lower stimulation frequency. Furthermore, motor unit recruitment using 100-Hz stimulation was not fully synchronized, as it occurs in classic NMES, and the discharge rates differed among motor units because each unit was activated only after a specific number of stimuli. The most likely mechanism behind these observations is the temporal summation of subthreshold excitatory postsynaptic potentials from Ia fibers to the MNs. These findings and their interpretation were also verified by a realistic simulation model of afferent stimulation of a MN population. These results suggest that the proposed stimulation strategy may allow generation of considerable levels of muscle activation by motor unit recruitment that resembles the physiological conditions.

  2. Improved bladder emptying in urinary retention by electrical stimulation of pudendal afferents

    NASA Astrophysics Data System (ADS)

    Peng, Chih-Wei; Chen, Jia-Jin Jason; Cheng, Chen-Li; Grill, Warren M.

    2008-06-01

    Urinary retention is the inability to empty the bladder completely, and may result from bladder hypocontractility, increases in outlet resistance or both. Chronic urinary retention can lead to several urological complications and is often refractory to pharmacologic, behavioral and surgical treatments. We sought to determine whether electrical stimulation of sensory fibers in the pudendal nerve could engage an augmenting reflex and thereby improve bladder emptying in an animal model of urinary retention. We measured the efficiency of bladder emptying with and without concomitant electrical stimulation of pudendal nerve afferents in urethane-anesthetized rats. Voiding efficiency (VE = voided volume/initial volume) was reduced from 72 ± 7% to 29 ± 7% following unilateral transection of the sensory branch of the pudendal nerve (UST) and from 70 ± 5% to 18 ± 4% following bilateral transection (BST). Unilateral electrical stimulation of the proximal transected sensory pudendal nerve during distention-evoked voiding contractions significantly improved VE. Low-intensity stimulation at frequencies of 1-50 Hz increased VE to 40-51% following UST and to 39-49% following BST, while high-intensity stimulation was ineffective at increasing VE. The increase in VE was mediated by increases in the duration of distention-evoked voiding bladder contractions, rather than increases in contraction amplitude. These results are consistent with an essential role for pudendal sensory feedback in efficient bladder emptying, and raise the possibility that electrical activation of pudendal nerve afferents may provide a new approach to restore efficient bladder emptying in persons with urinary retention.

  3. IMPROVED BLADDER EMPTYING IN URINARY RETENTION BY ELECTRICAL STIMULATION OF PUDENDAL AFFERENTS

    PubMed Central

    Peng, Chih-Wei; Chen, Jia-Jin Jason; Cheng, Chen-Li; Grill, Warren M.

    2013-01-01

    Urinary retention is the inability to empty the bladder completely, and may result from bladder hypocontractility, increases in outlet resistance, or both. Chronic urinary retention can lead to several urological complications and is often refractory to pharmacologic, behavioral, and surgical treatments. We sought to determine whether electrical stimulation of sensory fibers in the pudendal nerve could engage an augmenting reflex and thereby improve bladder emptying in an animal model of urinary retention. We measured the efficiency of bladder emptying with and without concomitant electrical stimulation of pudendal nerve afferents in urethane anesthetized rats. Voiding efficiency (VE=voided volume/initial volume) was reduced from 72±7% to 29±7% following unilateral transection of the sensory branch of the pudendal nerve (UST) and from 70±5% to 18±4% following bilateral transection (BST). Unilateral electrical stimulation of the proximal transected sensory pudendal nerve during distention-evoked voiding contractions significantly improved VE. Low intensity stimulation at frequencies of 1–50 Hz increased VE to 40–51% following UST and to 39–49% following BST, while high intensity stimulation was ineffective at increasing VE. The increase in VE was mediated by increases in the duration of distention-evoked voiding bladder contractions, rather than increases in contraction amplitude. These results are consistent with an essential role for pudendal sensory feedback in efficient bladder emptying, and raise the possibility that electrical activation of pudendal nerve afferents may provide a new approach to restore efficient bladder emptying in persons with urinary retention. PMID:18430976

  4. Electrical interaction between antidromically stimulated frog motoneurones and dorsal root afferents: enhancement by gallamine and TEA

    PubMed Central

    Grinnell, Alan D.

    1970-01-01

    1. Electrical interactions have been studied in the isolated frog spinal cord preparation. It is found that gallamine and tetraethylammonium chloride (TEA) markedly enhance all non-cholinergic synaptic interactions, including the electrical interaction between motoneurones (VR-VRP). In addition, in the presence of either of these drugs, a short-latency interaction is seen to exist between antidromically stimulated motoneurones and dorsal root afferents (early VR-DRP). The early VR-DRP is rarely seen in the absence of gallamine or TEA. 2. The early VR-DRP is of the same short latency as the VR-VRP and fulfils the same criteria for electrical interaction: it increases in amplitude with cooling from 17-10° C, it is not blocked by a wide variety of pharmacological blocking agents, and it is suppressed by both Mg2+ and Ca2+, with no antagonism of action between the two. 3. The early VR-DRP appears as a cluster of unitary events: all-or-none spikes conducted out the dorsal root fibres. No initial graded slow potentials are seen. Often there are two peaks in the response. 4. The early VR-DRP is facilitated by a dorsal root volley, with a time course normally intermediate between that of the orthodromic ventral root potential (DR-VRP) and the dorsal root potential (DR-DRP). This orthodromic facilitation apparently is achieved by increasing invasion of motoneurone dendritic trees and depolarization of dorsal root afferents toward threshold. 5. If the same ventral root is stimulated twice, or adjacent roots stimulated at different intervals, the second early VR-DRP, like the VR-VRP, is seen to be occluded for 10-20 msec, then facilitated to supranormal amplitudes. It is concluded that motoneurone dendrites are presynaptic to both interactions. 6. Evidence is presented that gallamine and TEA act by increasing the duration of activity both in axon terminals and in antidromically invaded motoneurones. Often second or multiple spikes result. The increased duration of

  5. Afferents contributing to autogenic inhibition of gastrocnemius following electrical stimulation of its tendon.

    PubMed

    Khan, Serajul I; Burne, John A

    2009-07-28

    Electrical stimulation of the Achilles tendon produced strong reflex inhibition of the ongoing voluntary EMG activity in the two heads of the gastrocnemius (GA) muscle in all tested subjects. The inhibition was seen clearly in both averaged and single sweep surface EMG records. The inhibitory response was produced without electrical (M wave) or mechanical, (muscle twitch) signs of direct muscle stimulation. The onset latency and duration for the first period of inhibition (I(1)) were 47-49 ms and 67 ms, respectively. A second inhibition (I(2)) had an onset latency of 187-193 ms and duration under 40 ms. Non-noxious stimuli in the range of 2.6-7.6 x mean perceptual threshold, when delivered to four locations over the GA tendon, all produced clear inhibition of the voluntary muscle activity. The inhibition was maximal when the cathode was a large metal plate located near the musculotendinous junction and decreased approximately linearly with distances more distal to that site. The effect of passive muscle stretch on the electrically induced tendon reflex inhibition (TRE) was tested at ankle joint angles incremented in steps of 20 degrees. It was found that TRE is strongly dependent on joint angle, being maximal in the fully stretched muscle. TRE was lost completely after partial tibial nerve block. In comparison, GA inhibition produced by cutaneous (sural) nerve stimulation was of a higher threshold, longer latency and persisted after partial tibial nerve block. We thus demonstrated a powerful autogenic inhibition in the lower limb arising from tendon afferents in conscious subjects that is increased by passive muscle stretch and likely to originate from group I tendon afferents.

  6. Effects of electrical and natural stimulation of skin afferents on the gamma-spindle system of the triceps surae muscle.

    PubMed

    Johansson, H; Sjölander, P; Sojka, P; Wadell, I

    1989-08-01

    The aim of the present study was to investigate the extent to which skin receptors might influence the responses of primary muscle spindle afferents via reflex actions on the fusimotor system. The experiments were performed on 43 cats anaesthetized with alpha-chloralose. The alterations in fusimotor activity were assessed from changes in the responses of the muscle spindle afferents to sinusoidal stretching of their parent muscles (triceps surae and plantaris). The mean rate of firing and the modulation of the afferent response were determined. Control measurements were made in absence of any cutaneous stimulation. Tests were made (a) during physiological stimulation of skin afferents of the ipsilateral pad or of the contralateral hindlimb, or (b) during repetitive electrical stimulation of the sural nerve in the ipsilateral hindlimb, or of sural or superficial peroneal nerve in the contralateral hindlimb. Of the total number of 113 units tested with repetitive electrical stimulation of the ipsilateral sural nerve (at 20 Hz), 24.8% exhibited predominantly dynamic fusimotor reflexes, 5.3% mixed or predominantly static fusimotor reflexes. One unit studied in a preparation with intact spinal cord exhibited static reflexes at low stimulation intensities and dynamic ones at higher stimulation strengths. The remaining units (69%) were uninfluenced. When the receptor-bearing muscle was held at constant length and a train of stimuli (at 20 Hz) was applied to the ipsilateral sural nerve, the action potentials in the primary muscle spindle afferent could be stimulus-locked to the 3rd or 4th pulse in the train (and to the pulses following thereafter), with a latency of about 24 ms from the effective pulse. This 1:1 pattern of driving seemed to be mediated via static and/or dynamic fusimotor neurons. Natural stimulation influenced comparatively few units (3 of 65 units tested from the ipsilateral pad and 10 of 98 tested from the contralateral hindlimb), but when the effects

  7. Vestibular implantation and longitudinal electrical stimulation of the semicircular canal afferents in human subjects

    PubMed Central

    Ling, Leo; Nie, Kaibao; Jameyson, Elyse; Phillips, Christopher M.; Nowack, Amy L.; Golub, Justin S.; Rubinstein, Jay T.

    2015-01-01

    Animal experiments and limited data in humans suggest that electrical stimulation of the vestibular end organs could be used to treat loss of vestibular function. In this paper we demonstrate that canal-specific two-dimensionally (2D) measured eye velocities are elicited from intermittent brief 2 s biphasic pulse electrical stimulation in four human subjects implanted with a vestibular prosthesis. The 2D measured direction of the slow phase eye movements changed with the canal stimulated. Increasing pulse current over a 0–400 μA range typically produced a monotonic increase in slow phase eye velocity. The responses decremented or in some cases fluctuated over time in most implanted canals but could be partially restored by changing the return path of the stimulation current. Implantation of the device in Meniere's patients produced hearing and vestibular loss in the implanted ear. Electrical stimulation was well tolerated, producing no sensation of pain, nausea, or auditory percept with stimulation that elicited robust eye movements. There were changes in slow phase eye velocity with current and over time, and changes in electrically evoked compound action potentials produced by stimulation and recorded with the implanted device. Perceived rotation in subjects was consistent with the slow phase eye movements in direction and scaled with stimulation current in magnitude. These results suggest that electrical stimulation of the vestibular end organ in human subjects provided controlled vestibular inputs over time, but in Meniere's patients this apparently came at the cost of hearing and vestibular function in the implanted ear. PMID:25652917

  8. Actions on gamma-motoneurones elicited by electrical stimulation of cutaneous afferent fibres in the hind limb of the cat.

    PubMed

    Johansson, H; Sojka, P

    1985-09-01

    The reflex actions elicited by graded electrical stimulation of hind-limb cutaneous (sural, superficial peroneal and tibial) nerves were investigated with intra- and extracellular micro-electrode recordings in gamma-motoneurones projecting to hind-limb muscles in twenty-four cats anaesthetized with alpha-chloralose. In total, reflex responses of 100 gamma-motoneurones were analysed. 82 of the gamma-cells were classified as dynamic (43) or static (39) using the method of mesencephalic stimulation (Appelberg, Hulliger, Johansson & Sojka, 1982). The general responsiveness (i.e. number of input nerves with effect/number of input nerves tested) of the whole sample of gamma-cells to stimulation of skin nerves was extremely high (94.8%). All negative observations were encountered among static and non-classified gamma-cells. Generally, the stimulation strengths needed for evoking effects in the gamma-cells were very low. A majority of the excitatory effects in the dynamic cells appeared with stimulation intensities below 1.5 threshold (T), while most static cells were excited with stimulation strengths between 1.5 and 2 T. Also a statistical comparison of the populations of stimulation strength thresholds for the excitatory effects revealed a significant difference (P less than 0.0009) between dynamic and static gamma-cells. By contrast, the thresholds for inhibitory effects in dynamic cells were slightly higher than for excitatory effects (P less than 0.0009). As regards excitation of static cells, inhibition of dynamic cells and inhibition of static cells, no statistically significant threshold differences were found. A strong dominance of excitation over inhibition was found in both dynamic and static flexor (posterior biceps and semitendinosus) gamma-motoneurones from all input nerves. In comparison to flexor gamma-motoneurones, there was a much higher incidence of inhibitory and mixed (excitatory and inhibitory) responses in extensor (triceps) gamma-motoneurones, from

  9. Involvement of peripheral ionotropic glutamate receptors in activation of cutaneous branches of spinal dorsal rami following antidromic electrical stimulation of adjacent afferent nerves in rats.

    PubMed

    Cao, Dong-Yuan; You, Hao-Jun; Zhao, Yan; Guo, Yuan; Wang, Hui-Sheng; Arendt-Nielsen, Lars; Wang, Hui-Ling; Zhang, Qi

    2007-04-02

    The aim of the present study was to investigate the role of peripheral ionotropic glutamate receptors in the process of signal transmission between adjacent different peripheral sensory nerves. The T9 and T10 cutaneous branches of spinal dorsal rami were dissociated and cut proximally in pentobarbital anesthetized rats. Eighty-seven single afferents from T10 nerve filaments were recorded and characterized by assessing their spontaneous activities. Following 30 s antidromic electrical stimulation (intensity: 1 mA; duration: 0.5 ms; frequency: 20 Hz) of T9 cutaneous branches, the spontaneous activities of Abeta, Adelta and C fibers of T10 nerve were significantly enhanced from 2.00+/-0.34, 2.42+/-0.33, and 2.19+/-0.32 impulses/min to 4.31+/-0.58, 5.22+/-0.55, and 5.27+/-0.69 impulses/min, respectively (n=29 for each type, P<0.05). These enhanced spontaneous discharges of T10 nerve were significantly blocked by local treatment of its receptive field with either N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 or non-NMDA receptor antagonist DNQX (0.1 mM, 10 microl for each drug) (P<0.05). These results suggest that peripheral ionotropic glutamate receptors are involved in the activation of peripheral nerves following the antidromic stimulation of adjacent afferents from different spinal segments. We further provide the direct evidence that neurotransmitters released from adjacent peripheral nerves may also contribute to the occurrence of allodynia as well as secondary hyperalgesia during the pathological nociception.

  10. Closed-loop afferent electrical stimulation for recovery of hand function in individuals with motor incomplete spinal injury: early clinical results.

    PubMed

    Schildt, Christopher J; Thomas, Sarah H; Powell, Elizabeth S; Sawaki, Lumy; Sunderam, Sridhar

    2016-08-01

    Afferent electrical stimulation is known to augment the effect of rehabilitative therapy through use-dependent cortical plasticity. Experiments pairing transcranial magnetic stimulation (TMS) with peripheral nerve stimulation (PNS) have shown a timing-dependent effect on motor evoked potential (MEP) amplitude suggesting that PNS applied in closed-loop (CL) mode could augment this effect through positive reinforcement. We present early results from a clinical trial in which an EEG brain-machine interface (BMI) was used to apply PNS to two subjects in response to motor intent detected from sensorimotor cortex in a cue-driven hand grip task. Both subjects had stable incomplete cervical spinal cord injury (SCI) with impaired upper limb function commensurate with the injury level. Twelve sessions of CL-PNS applied over a 4-6 week period yielded results suggesting improved hand grip strength and increased task-related modulation of the EEG in one hand of both subjects, and increased TMS-measured motor map area in one. These observations suggest that rehabilitation using such interactive therapies could benefit affected individuals.

  11. Primary afferent depolarization and flexion reflexes produced by radiant heat stimulation of the skin.

    PubMed

    Burke, R E; Rudomin, P; Vyklický, L; Zajac, F E

    1971-02-01

    1. The reflex effects of pulses of intense radiant heat applied to the skin of the central plantar pad have been studied in unanaesthetized (decerebrate) spinal cats.2. Pad heat pulses produced flexion of the ipsilateral hind limb and increased ipsilateral flexor monosynaptic reflexes, due to post-synaptic excitation of flexor alpha motoneurones. These effects were accompanied by reduction of extensor monosynaptic reflexes and post-synaptic inhibition of extensor motoneurones.3. Ipsilateral (and contralateral) pad heat pulses consistently evoked negative dorsal root potentials (DRPs) as well as increased excitability of both cutaneous and group Ib muscle afferent terminals. The excitability of group Ia afferents was sometimes also increased during pad heat pulses, but to a lesser extent.4. Pad heat pulses produced negative DRPs in preparations in which positive DRP components could be demonstrated following electrical stimulation of both skin and muscle nerves.5. The motor and primary afferent effects of heat pulses always accompanied one another, beginning after the pad surface temperature had reached rather high levels (usually 48-55 degrees C).6. Negative DRPs increased excitability of cutaneous and group Ib afferents, and motoneurone activation produced by pad heat pulses was essentially unmodified when conduction in large myelinated afferents from the central plantar pad was blocked by cooling the posterior tibial nerve trunk.7. It is concluded that adequate noxious activation of cutaneous afferents of small diameter produces primary afferent depolarization in a variety of large diameter afferent fibres, as well as post-synaptic effects in alpha motoneurones.

  12. Primary afferent depolarization and flexion reflexes produced by radiant heat stimulation of the skin

    PubMed Central

    Burke, R. E.; Rudomin, P.; Vyklický, L.; Zajac, F. E.

    1971-01-01

    1. The reflex effects of pulses of intense radiant heat applied to the skin of the central plantar pad have been studied in unanaesthetized (decerebrate) spinal cats. 2. Pad heat pulses produced flexion of the ipsilateral hind limb and increased ipsilateral flexor monosynaptic reflexes, due to post-synaptic excitation of flexor alpha motoneurones. These effects were accompanied by reduction of extensor monosynaptic reflexes and post-synaptic inhibition of extensor motoneurones. 3. Ipsilateral (and contralateral) pad heat pulses consistently evoked negative dorsal root potentials (DRPs) as well as increased excitability of both cutaneous and group Ib muscle afferent terminals. The excitability of group Ia afferents was sometimes also increased during pad heat pulses, but to a lesser extent. 4. Pad heat pulses produced negative DRPs in preparations in which positive DRP components could be demonstrated following electrical stimulation of both skin and muscle nerves. 5. The motor and primary afferent effects of heat pulses always accompanied one another, beginning after the pad surface temperature had reached rather high levels (usually 48-55° C). 6. Negative DRPs increased excitability of cutaneous and group Ib afferents, and motoneurone activation produced by pad heat pulses was essentially unmodified when conduction in large myelinated afferents from the central plantar pad was blocked by cooling the posterior tibial nerve trunk. 7. It is concluded that adequate noxious activation of cutaneous afferents of small diameter produces primary afferent depolarization in a variety of large diameter afferent fibres, as well as post-synaptic effects in alpha motoneurones. PMID:5575337

  13. Comparison of the inhibitory response to tendon and cutaneous afferent stimulation in the human lower limb.

    PubMed

    Rogasch, Nigel C; Burne, John A; Türker, Kemal S

    2012-01-01

    A powerful early inhibition is seen in triceps surae after transcutaneous electrical stimulation of the Achilles tendon [tendon electrical stimulation (TES)]. The aim of the present study was to confirm results from surface electromyogram (SEMG) recordings that the inhibition is not wholly or partly due to stimulation of cutaneous afferents that may lie within range of the tendon electrodes. Because of methodological limitations, SEMG does not reliably identify the time course of inhibitory and excitatory reflex components. This issue was revisited here with an analysis of changes in single motor unit (SMU) firing rate [peristimulus frequencygram (PSF)] and probability [peristimulus time histogram (PSTH)] to reexamine the time course of inhibitory SMU events that follow purely cutaneous (superficial sural) nerve stimulation. Results were then compared with similar data from TES. When compared with the reflex response to TES, sural nerve stimulation resulted in a longer onset latency of the primary inhibition and a weaker effect on SMU firing probability and rate. PSF also revealed that decreased SMU firing rates persisted during the excitation phase in SEMG, suggesting that the initial inhibition was more prolonged than previously reported. In a further study, the transcutaneous SEMG Achilles tendon response was compared with that from direct intratendon stimulation with insulated needle electrodes. This method should attenuate the SEMG response if it is wholly or partly dependent on cutaneous afferents. However, subcutaneous stimulation of the tendon produced similar components in the SEMG, confirming that cutaneous afferents made little or no contribution to the initial inhibition following TES.

  14. Primary afferent depolarization of muscle afferents elicited by stimulation of joint afferents in cats with intact neuraxis and during reversible spinalization.

    PubMed

    Quevedo, J; Eguibar, J R; Jiménez, I; Schmidt, R F; Rudomin, P

    1993-11-01

    1. In the anesthetized and artificially ventilated cat, stimulation of the posterior articular nerve (PAN) with low strengths (1.2-1.4 x T) produced a small negative response (N1) in the cord dorsum of the lumbosacral spinal cord with a mean onset latency of 5.2 ms. Stronger stimuli (> 1.4 x T) produced two additional components (N2 and N3) with longer latencies (mean latencies 7.5 and 15.7 ms, respectively), usually followed by a slow positivity lasting 100-150 ms. With stimulus strengths above 10 x T there was in some experiments a delayed response (N4; mean latency 32 ms). 2. Activation of posterior knee joint nerve with single pulses and intensities producing N1 responses only, usually produced no dorsal root potentials (DRPs), or these were rather small. Stimulation with strengths producing N2 and N3 responses produced distinct DRPs. Trains of pulses were clearly more effective than single pulses in producing DRPs, even in the low-intensity range. 3. Cooling the thoracic spinal cord to block impulse conduction, increased the DRPs and the N3 responses produced by PAN stimulation without significantly affecting the N2 responses. Reversible spinalization also increased the DRPs produced by stimulation of cutaneous nerves. In contrast, the DRPs produced by stimulation of group I afferents from flexors were reduced. 4. Conditioning electrical stimulation of intermediate and high-threshold myelinated fibers in the PAN depressed the DRPs produced by stimulation of group I muscle and of cutaneous nerves. 5. Analysis of the intraspinal threshold changes of single Ia and Ib fibers has provided evidence that stimulation of intermediate and high threshold myelinated fibers in the posterior knee joint nerve inhibits the primary afferent depolarization (PAD) of Ia fibers, and may either produce PAD or inhibit the PAD in Ib fibers, in the same manner as stimulation of cutaneous nerves. In 7/16 group I fibers the inhibition of the PAD was increased during reversible

  15. Cerebral, subcortical, and cerebellar activation evoked by selective stimulation of muscle and cutaneous afferents: an fMRI study.

    PubMed

    Wardman, Daniel L; Gandevia, Simon C; Colebatch, James G

    2014-01-01

    Abstract We compared the brain areas that showed significant flow changes induced by selective stimulation of muscle and cutaneous afferents using fMRI BOLD imaging. Afferents arising from the right hand were studied in eight volunteers with electrical stimulation of the digital nerve of the index finger and over the motor point of the FDI muscle. Both methods evoked areas of significant activation cortically, subcortically, and in the cerebellum. Selective muscle afferent stimulation caused significant activation in motor-related areas. It also caused significantly greater activation within the contralateral precentral gyrus, insula, and within the ipsilateral cerebellum as well as greater areas of reduced blood flow when compared to the cutaneous stimuli. We demonstrated separate precentral and postcentral foci of excitation with muscle afferent stimulation. We conclude, contrary to the findings with evoked potentials, that muscle afferents evoke more widespread cortical, subcortical, and cerebellar activation than do cutaneous afferents. This emphasizes the importance, for studies of movement, of matching the kinematic aspects in order to avoid the results being confounded by alterations in muscle afferent activation. The findings are consistent with clinical observations of the movement consequences of sensory loss and may also be the basis for the contribution of disturbed sensorimotor processing to disorders of movement.

  16. Cerebral, subcortical, and cerebellar activation evoked by selective stimulation of muscle and cutaneous afferents: an fMRI study

    PubMed Central

    Wardman, Daniel L.; Gandevia, Simon C.; Colebatch, James G.

    2014-01-01

    Abstract We compared the brain areas that showed significant flow changes induced by selective stimulation of muscle and cutaneous afferents using fMRI BOLD imaging. Afferents arising from the right hand were studied in eight volunteers with electrical stimulation of the digital nerve of the index finger and over the motor point of the FDI muscle. Both methods evoked areas of significant activation cortically, subcortically, and in the cerebellum. Selective muscle afferent stimulation caused significant activation in motor‐related areas. It also caused significantly greater activation within the contralateral precentral gyrus, insula, and within the ipsilateral cerebellum as well as greater areas of reduced blood flow when compared to the cutaneous stimuli. We demonstrated separate precentral and postcentral foci of excitation with muscle afferent stimulation. We conclude, contrary to the findings with evoked potentials, that muscle afferents evoke more widespread cortical, subcortical, and cerebellar activation than do cutaneous afferents. This emphasizes the importance, for studies of movement, of matching the kinematic aspects in order to avoid the results being confounded by alterations in muscle afferent activation. The findings are consistent with clinical observations of the movement consequences of sensory loss and may also be the basis for the contribution of disturbed sensorimotor processing to disorders of movement. PMID:24771687

  17. Frequency dependent changes in mechanosensitivity of rat knee joint afferents after antidromic saphenous nerve stimulation.

    PubMed

    Just, S; Heppelmann, B

    2002-01-01

    The aim of the present study was to examine the effect of electrical saphenous nerve stimulation (14 V, 1-10 Hz) on the mechanosensitivity of rat knee joint afferents. The responses to passive joint rotations at defined torque were recorded from slowly conducting knee joint afferent nerve fibres (0.6-20.0 m/s). After repeated nerve stimulation with 1 Hz, the mechanosensitivity of about 79% of the units was significantly affected. The effects were most prominent at a torque close to the mechanical threshold. In about 46% of the examined nerve fibres a significant increase was obtained, whereas about 33% reduced their mechanosensitivity. The sensitisation was prevented by an application of 5 microM phentolamine, an alpha-adrenergic receptor blocker, together with a neuropeptide Y receptor blocker. An inhibition of N-type Ca(2+) channels by an application of 1 microM omega-conotoxin GVIA caused comparable changes of the mechanosensitivity during the electrical stimulation. Electrical nerve stimulation with higher frequencies resulted in a further reduction of the mean response to joint rotations. After stimulation with 10 Hz, there was a nearly complete loss of mechanosensitivity.In conclusion, antidromic electrical nerve stimulation leads to a frequency dependent transient decrease of the mechanosensitivity. A sensitisation was only obtained at 1 Hz, but this effect may be based on the influence of sympathetic nerve fibres.

  18. Hydrogen sulfide determines HNO-induced stimulation of trigeminal afferents.

    PubMed

    Wild, Vanessa; Messlinger, Karl; Fischer, Michael J M

    2015-08-18

    Endogenous NO and hydrogen sulfide form HNO, which causes CGRP release via TRPA1 channel activation in sensory nerves. In the present study, stimulation of intact trigeminal afferent neuron preparations with NO donors, Na2S or both was analyzed by measuring CGRP release as an index of mass activation. Combined stimulation was able to activate all parts of the trigeminal system and acted synergistic compared to stimulation with both substances alone. To investigate the contribution of both substances, we varied their ratio and tracked intracellular calcium in isolated neurons. Our results demonstrate that hydrogen sulfide is the rate-limiting factor for HNO formation. CGRP has a key role in migraine pathophysiology and HNO formation at all sites of the trigeminal system should be considered for this novel means of activation.

  19. Primary afferent neurons of the electrosensory system of paddlefish respond to the electrical signal of paddlefish moving prey.*

    NASA Astrophysics Data System (ADS)

    Wojtenek, Winfried; Neiman, Alexander; Moss, Frank; Wilkens, Lon

    2000-03-01

    The elongated rostrum and ampullae of Lorenzini of paddlefish (Polyodon spathula) function as an antenna for detecting electrical signals from planktonic prey (1,2). We characterize the weak electric field of the water flea (Daphnia), the natural prey of paddlefish, and the response of the electroreceptor primary afferents to the live plankton. Daphnia generate a steady DC electric field with a low-frequency AC component. The DC field is dipolar, with low-frequency AC modulations (5-10 Hz) of 10-20peak-to-peak amplitude of the steady DC electric field. Primary afferents discharge rate are briefly increased or decreased when Daphnia swept over their receptive fields. Cathodal stimulation increases the primary afferent spike rate, whereas anodal stimuli decrease neuronal activity. The pattern of neuronal discharge depend on dipole orientation and, in general, neuronal discharges follow the characteristic of moving Daphnia’s electric potentials.

  20. Somatostatin inhibits activation of dorsal cutaneous primary afferents induced by antidromic stimulation of primary afferents from an adjacent thoracic segment in the rat.

    PubMed

    Guo, Yuan; Yao, Fan-Rong; Cao, Dong-Yuan; Pickar, Joel G; Zhang, Qi; Wang, Hui-Sheng; Zhao, Yan

    2008-09-10

    To investigate the effect of somatostatin on the cross-excitation between adjacent primary afferent terminals in the rats, we recorded single unit activity from distal cut ends of dorsal cutaneous branches of the T10 and T12 spinal nerves in response to antidromic stimulation of the distal cut end of the T11 dorsal root in the presence and absence of somatostatin and its receptor antagonist applied to the receptive field of the recorded nerve. Afferent fibers were classified based upon their conduction velocity. Mean mechanical thresholds decreased and spontaneous discharge rates increased significantly in C and Adelta but not Abeta fibers of the T10 and T12 spinal nerves in both male and female rats following antidromic electrical stimulation (ADES) of the dorsal root from adjacent spinal segment (DRASS) indicating cross-excitation of thin fiber afferents. The cross-excitation was not significantly different between male and female rats. Microinjection of somatostatin into the receptive field of recorded units inhibited the cross-excitation. This inhibitory effect, in turn, was reversed by the somatostation receptor antagonist cyclo-somatostatin (c-SOM). Application of c-SOM alone followed by ADES of DRASS significantly decreased the mechanical thresholds and increased the discharge rates of C and Adelta fibers, indicating that endogenous release of somatostatin plays a tonic inhibitory role on the cross-excitation between peripheral nerves. These results suggest that somatostatin could inhibit the cross-excitation involved in peripheral hyperalgesia and have a peripheral analgesic effect.

  1. Evidence that antidromically stimulated vagal afferents activate inhibitory neurones innervating guinea-pig trachealis.

    PubMed Central

    Canning, B J; Undem, B J

    1994-01-01

    1. We recently described a capsaicin-sensitive vagal pathway mediating non-adrenergic, non-cholinergic (NANC) relaxations of an isolated, innervated rostral guinea-pig tracheal preparation. These afferent fibres are carried by the superior laryngeal nerves and relaxations elicited by their activation are insensitive to autonomic ganglion blockers such as hexamethonium. In the present study this vagal relaxant pathway was further characterized. 2. Relaxations of the trachealis elicited by electrical stimulation of capsaicin-sensitive vagal afferents were mimicked by bath application of capsaicin. Relaxations elicited by both methods were abolished when the tissue between the trachea and the adjacent oesophagus was disrupted. Indeed, separating the trachea from the oesophagus uncovered a contractile effect of capsaicin administration on the trachealis. 3. Capsaicin-induced, oesophagus-dependent relaxations of the trachealis were blocked by pretreatment with the fast sodium channel blocker tetrodotoxin (TTX). By contrast, capsaicin-induced contractions of the trachealis (obtained in the absence of the oesophagus) were unaffected by tetrodotoxin. 4. Substance P, neurokinin A (NKA) and neurokinin B (NKB) also elicited NANC relaxations of precontracted trachealis that were abolished by separating the trachea from the oesophagus or by TTX pretreatment. Like capsaicin, the tachykinins elicited only contractions of the trachealis following TTX pretreatment or separation of the trachea from the adjacent oesophagus. 5. Relaxations elicited by stimulation of the capsaicin-sensitive nerves were unaffected by a concentration of the tachykinin NK2 receptor-selective antagonist, SR 48968, that is selective for NK2 receptor blockade and were not mimicked by the NK2 receptor-selective agonist [beta-Ala8]-NKA(4-10). This suggests that NK2 receptors are not responsible for these relaxations. By contrast, the NK3 receptor-selective agonist, senktide analogue, and the NK1 receptor

  2. Post-stimulation Inhibitory Effect on Reflex Bladder Activity Induced by Activation of Somatic Afferent Nerves in the Foot

    PubMed Central

    Chen, Guoqing; Larson, Jeffrey A.; Ogagan, P. Dafe; Shen, Bing; Wang, Jicheng; Roppolo, James R.; de Groat, William C.; Tai, Changfeng

    2011-01-01

    Purpose To determine if transcutaneous electrical stimulation of somatic afferent nerves in the foot of cats can induce a post-stimulation increase in bladder capacity. Materials and Methods In α-chloralose anesthetized cats (N=12) electrical stimulation (5 Hz) was applied to the skin of the hind foot for two periods of 30 minutes via dual pad electrodes attached on the plantar and dorsal surfaces (combination 1-2) or at two sites on the plantar surface (combination 1-3). The post-stimulation effect was examined by performing repeated CMGs following 30 minute stimulation. In the control group (N=12) the isovolumetric contractions were allowed to continue during each 30 minute period without stimulation. Results Stimulation inhibited isovolumetric rhythmic bladder contractions. The bladder capacity was not increased after the first 30 minute foot stimulation via electrode combination 1-2, but was significantly increased 47.5±2.9% after the second 30 minute stimulation via electrode combination 1-3. After inducing the post-stimulation effect, the foot stimulation applied during CMGs via electrode combinations 1-2 or 1-3 elicited a further increase in bladder capacity (23.26±17.64% and 20.07±18.59% respectively). Conclusions This study shows that the transcutaneous plantar electrical stimulation of somatic afferent nerves in the foot can induce a post-stimulation increase in bladder capacity, suggesting that an intermittent stimulation pattern rather than a continuous stimulation might be effective in clinical applications to treat overactive bladder symptoms. PMID:22099982

  3. Synaptic depression in the CA1 region of freely behaving mice is highly dependent on afferent stimulation parameters

    PubMed Central

    Goh, Jinzhong J.; Manahan-Vaughan, Denise

    2012-01-01

    Persistent synaptic plasticity has been subjected to intense study in the decades since it was first described. Occurring in the form of long-term potentiation (LTP) and long-term depression (LTD), it shares many cellular and molecular properties with hippocampus-dependent forms of persistent memory. Recent reports of both LTP and LTD occurring endogenously under specific learning conditions provide further support that these forms of synaptic plasticity may comprise the cellular correlates of memory. Most studies of synaptic plasticity are performed using in vitro or in vivo preparations where patterned electrical stimulation of afferent fibers is implemented to induce changes in synaptic strength. This strategy has proven very effective in inducing LTP, even under in vivo conditions. LTD in vivo has proven more elusive: although LTD occurs endogenously under specific learning conditions in both rats and mice, its induction has not been successfully demonstrated with afferent electrical stimulation alone. In this study we screened a large spectrum of protocols that are known to induce LTD either in hippocampal slices or in the intact rat hippocampus, to clarify if LTD can be induced by sole afferent stimulation in the mouse CA1 region in vivo. Low frequency stimulation at 1, 2, 3, 5, 7, or 10 Hz given in the range of 100 through 1800 pulses produced, at best, short-term depression (STD) that lasted for up to 60 min. Varying the administration pattern of the stimuli (e.g., 900 pulses given twice at 5 min intervals), or changing the stimulation intensity did not improve the persistency of synaptic depression. LTD that lasts for at least 24 h occurs under learning conditions in mice. We conclude that a coincidence of factors, such as afferent activity together with neuromodulatory inputs, play a decisive role in the enablement of LTD under more naturalistic (e.g., learning) conditions. PMID:23355815

  4. Plasticity of urinary bladder reflexes evoked by stimulation of pudendal afferent nerves after chronic spinal cord injury in cats.

    PubMed

    Tai, Changfeng; Chen, Mang; Shen, Bing; Wang, Jicheng; Liu, Hailong; Roppolo, James R; de Groat, William C

    2011-03-01

    Bladder reflexes evoked by stimulation of pudendal afferent nerves (PudA-to-Bladder reflex) were studied in normal and chronic spinal cord injured (SCI) adult cats to examine the reflex plasticity. Physiological activation of pudendal afferent nerves by tactile stimulation of the perigenital skin elicits an inhibitory PudA-to-Bladder reflex in normal cats, but activates an excitatory reflex in chronic SCI cats. However, in both normal and chronic SCI cats electrical stimulation applied to the perigenital skin or directly to the pudendal nerve induces either inhibitory or excitatory PudA-to-Bladder reflexes depending on stimulation frequency. An inhibitory response occurs at 3-10 Hz stimulation, but becomes excitatory at 20-30 Hz. The inhibitory reflex activated by electrical stimulation significantly (P<0.05) increases the bladder capacity to about 180% of control capacity in normal and chronic SCI cats. The excitatory reflex significantly (P<0.05) reduces bladder capacity to about 40% of control capacity in chronic SCI cats, but does not change bladder capacity in normal cats. Electrical stimulation of pudendal afferent nerves during slow bladder filling elicits a large amplitude bladder contraction comparable to the contraction induced by distension alone. A bladder volume about 60% of bladder capacity was required to elicit this excitatory reflex in normal cats; however, in chronic SCI cats a volume less than 20% of bladder capacity was sufficient to unmask an excitatory response. This study revealed the co-existence of both inhibitory and excitatory PudA-to-Bladder reflex pathways in cats before and after chronic SCI. However our data combined with published electrophysiological data strongly indicates that the spinal circuitry for both the excitatory and inhibitory PudA-to-Bladder reflexes undergoes a marked reorganization after SCI.

  5. Modelling spinal circuitry involved in locomotor pattern generation: insights from the effects of afferent stimulation

    PubMed Central

    Rybak, Ilya A; Stecina, Katinka; Shevtsova, Natalia A; McCrea, David A

    2006-01-01

    A computational model of the mammalian spinal cord circuitry incorporating a two-level central pattern generator (CPG) with separate half-centre rhythm generator (RG) and pattern formation (PF) networks has been developed from observations obtained during fictive locomotion in decerebrate cats. Sensory afferents have been incorporated in the model to study the effects of afferent stimulation on locomotor phase switching and step cycle period and on the firing patterns of flexor and extensor motoneurones. Here we show that this CPG structure can be integrated with reflex circuits to reproduce the reorganization of group I reflex pathways occurring during locomotion. During the extensor phase of fictive locomotion, activation of extensor muscle group I afferents increases extensor motoneurone activity and prolongs the extensor phase. This extensor phase prolongation may occur with or without a resetting of the locomotor cycle, which (according to the model) depends on the degree to which sensory input affects the RG and PF circuits, respectively. The same stimulation delivered during flexion produces a temporary resetting to extension without changing the timing of following locomotor cycles. The model reproduces this behaviour by suggesting that this sensory input influences the PF network without affecting the RG. The model also suggests that the different effects of flexor muscle nerve afferent stimulation observed experimentally (phase prolongation versus resetting) result from opposing influences of flexor group I and II afferents on the PF and RG circuits controlling the activity of flexor and extensor motoneurones. The results of modelling provide insights into proprioceptive control of locomotion. PMID:17008375

  6. Reflex control of locomotion as revealed by stimulation of cutaneous afferents in spontaneously walking premammillary cats.

    PubMed

    Duysens, J

    1977-07-01

    1. Stimulation of different hindlimb nerves in spontaneously walking premammillary cats was used in order to examine the effects of sensory input on the rhythmic motor output. 2. Stimulation of the tibial or sural nerve at low intensities caused the burst of activity in the triceps surae or semimembranosus to be prolonged if stimuli were given during the extension phase. When applied during the flexion phase, the same stimuli shortened the burst of activity in the pretibial flexors and induced an early onset of the extensor activity, except if stimuli were given at the very beginning of the flexion phase, when flexor burst prolongations or rebounds were observed instead. 3. These effects were related to activation of large cutaneous afferents in these nerves since the results could be duplicated by low-intensity stimulation of the tibial nerve at the ankle or by direct stimulation of the pad. 4. In contrast, activation of smaller afferents by high-intensity stimulation resulted prolongations of the flexor burst and/or shortenings of the extensor burst for stimuli applied before or during these bursts, respectively. 5. It was concluded that the large and small cutaneous afferents make, respectively, inhibitory and excitatory connections with the central structure involved in the generation of flexion during walking.

  7. [Effects of afferent vagal stimulation and distention of the upper digestive tract on the micturition reflex and activity of the pontine micturition center in dogs].

    PubMed

    Moda, Y

    1992-12-01

    (1) The study was performed to elucidate the effects of afferent vagal stimulation and distension of the digestive tract on the micturition reflex in 21 acute decerebrate dogs immobilized with gallamine. Electrical stimulation of the central cut end of the cervical vagus nerve with high voltage (17.5-25 V) and moderate frequency (10-50 Hz) elicited in most cases inhibition of the periodic bladder contractions and of outflows of the pelvic vesical branch which were induced by a sustained intravesical pressure of 10-15 cmH2O. Distension of the thoracic esophagus, the stomach, and the duodenum also induced inhibition of the bladder contractions and of the pelvic outflow to the bladder. Such inhibitions were abolished after bilateral cervical vagotomies except a few cases of distension of the duodenum. (2) Another series of experiments were undertaken to clear the effect of afferent vagal stimulation on the electrical activity of the pontine micturition center in 10 acute decerebrate dogs. By means of an extracellular glass microelectrode method, unitary discharges synchronized with the grouping discharges in the pelvic vesical branch with a rhythm of 2.2-2.5 Hz were recorded from the pontine micturition center in the dorsolateral pontine tegmentum. Such a type of discharges was detected in 6 of 59 units which discharged by afferent stimulation of the pelvic vesical branch. This type of discharges was inhibited by afferent vagal stimulation at the supradiaphragmatic level. From these results, it may be concluded that the afferent pathway of the bladder relaxation reflex induced by distension of the upper digestive tract is mainly involved in the vagal nerves, but in some cases of the strong distension of the duodenum, the pathway is in splanchnic nerves, and that inhibition of the bladder contraction after stimulation of vagal nerve is induced by suppression of the pontine micturition centers.

  8. Electrical carotid sinus stimulation in treatment resistant arterial hypertension.

    PubMed

    Jordan, Jens; Heusser, Karsten; Brinkmann, Julia; Tank, Jens

    2012-12-24

    Treatment resistant arterial hypertension is commonly defined as blood pressure that remains above goal in spite of the concurrent use of three antihypertensive agents of different classes. The sympathetic nervous system promotes arterial hypertension and cardiovascular as well as renal damage, thus, providing a logical treatment target in these patients. Recent physiological studies suggest that baroreflex mechanisms contribute to long-term control of sympathetic activity and blood pressure providing an impetus for the development of electrical carotid sinus stimulators. The concept behind electrical stimulation of baroreceptors or baroreflex afferent nerves is that the stimulus is sensed by the brain as blood pressure increase. Then, baroreflex efferent structures are adjusted to counteract the perceived blood pressure increase. Electrical stimulators directly activating afferent baroreflex nerves were developed years earlier but failed for technical reasons. Recently, a novel implantable device was developed that produces an electrical field stimulation of the carotid sinus wall. Carefully conducted experiments in dogs provided important insight in mechanisms mediating the depressor response to electrical carotid sinus stimulation. Moreover, these studies showed that the treatment success may depend on the underlying pathophysiology of the hypertension. Clinical studies suggest that electrical carotid sinus stimulation attenuates sympathetic activation of vasculature, heart, and kidney while augmenting cardiac vagal regulation, thus lowering blood pressure. Yet, not all patients respond to treatment. Additional clinical trials are required. Patients equipped with an electrical carotid sinus stimulator provide a unique opportunity gaining insight in human baroreflex physiology.

  9. Stimulation of renal afferent fibers leads to activation of catecholaminergic and non-catecholaminergic neurons in the medulla oblongata.

    PubMed

    Nishi, Erika E; Martins, Beatriz S; Milanez, Maycon I O; Lopes, Nathalia R; de Melo, Jose F; Pontes, Roberto B; Girardi, Adriana C; Campos, Ruy R; Bergamaschi, Cássia T

    2017-01-19

    Presympathetic neurons in the rostral ventrolateral medulla (RVLM) including the adrenergic cell groups play a major role in the modulation of several reflexes required for the control of sympathetic vasomotor tone and blood pressure (BP). Moreover, sympathetic vasomotor drive to the kidneys influence natriuresis and diuresis by inhibiting the cAMP/PKA pathway and redistributing the Na(+)/H(+) exchanger isoform 3 (NHE3) to the body of the microvilli in the proximal tubules. In this study we aimed to evaluate the effects of renal afferents stimulation on (1) the neurochemical phenotype of Fos expressing neurons in the medulla oblongata and (2) the level of abundance and phosphorylation of NHE3 in the renal cortex. We found that electrical stimulation of renal afferents increased heart rate and BP transiently and caused activation of tyrosine hydroxylase (TH)-containing neurons in the RVLM and non-TH neurons in the NTS. Additionally, activation of the inhibitory renorenal reflex over a 30-min period resulted in increased natriuresis and diuresis associated with increased phosphorylation of NHE3 at serine 552, a surrogate for reduced activity of this exchanger, in the contralateral kidney. This effect was not dependent of BP changes considering that no effects on natriuresis or diuresis were found in the ipsilateral-stimulated kidney. Therefore, our data show that renal afferents leads to activation of catecholaminergic and non-catecholaminergic neurons in the medulla oblongata. When renorenal reflex is induced, NHE3 exchanger activity appears to be decreased, resulting in decreased sodium and water reabsorption in the contralateral kidney.

  10. [Postsynaptic reactions of cerebral cortex neurons, activated by nociceptive afferents during stimulation of the Raphe nuclei].

    PubMed

    Labakhua, T Sh; Dzhanashiia, T K; Gedevanishvili, G I; Dzhokhadze, L D; Tkemaladze, T T; Abzianidze, I V

    2012-01-01

    On cats, we studied the influence of stimulation of the Raphe nuclei (RN) on postsynaptic processes evoked in neurons of the somatosensory cortex by stimulation of nociceptive (intensive stimulation of the tooth pulp) and non-nociceptive (moderate stimulation of the ventroposteromedial--VPN--nucleus of the thalamus) afferent inputs. 6 cells, selectively excited by stimulation of nocciceptors and 9 cells, activated by both the above nociceptive and non-nociceptive influences (nociceptive and convergent neurons, respectively) were recorded intracellular. In neurons of both groups, responses to nociceptive stimulation (of sufficient intensity) looked like an EPSP-spike-IPSP (the letter of significant duration, up to 200-300 ms) compleх. Conditioning stimulation of the RN which preceded test stimulus applied to the tooth pulp or VPM nucleus by 100 to 800 ms, induced 40-60 % decrease of the IPSP amplitude only, while maхimal effect of influence, in both cases, was noted within intervals of 300-800 ms between conditioning and test stimulus. During stimulation of the RN, serotonin released via receptor and second messengers, provides postsynaptic modulation of GABAergic system, decreasing the IPSP amplitude which occurs after stimulation of both the tooth pulp and VPM thalamic nucleus. This process may be realized trough either pre- or postsynaptic mechanisms.

  11. [Readjustment of the efferent activity of the scratching generator in response to stimulation of cutaneous afferents of the hindlimb of the decerebrate immobilized cat].

    PubMed

    Shimanskiĭ, Iu P; Baev, K V

    1987-01-01

    Rebuildings of the scratching generator efferent activity caused by the phasic electrical stimulation of ipsilateral hindlimb skin nerves during different hindlimb positions were studied in decerebrated immobilized cats. Stimulation was followed by short latency inhibition of the efferent activity. Stimulation did not cause correlation shifts in the common "aiming" and "scratching" activity. Changes in the efferent activity cycle duration and intensity depended on the stimulation phase. Inversion of intensity changes occurred with transition from the middle-force to strong stimulation. A functional role of the dependence of the efferent activity rebuilding on the stimulation phase is considered. The scratching generator is supposed to contain a model of the afferent inflow which enters the spinal cord during real scratching.

  12. Short-latency tachycardia evoked by stimulation of muscle and cutaneous afferents.

    PubMed

    Gelsema, A J; Bouman, L N; Karemaker, J M

    1985-04-01

    The short-latency effect on heart rate of peripheral nerve stimulation was studied in decerebrate cats. Selective activation (17-40 microA, 100 Hz, 1 s long) of low-threshold fibers in the nerves to the triceps surae muscle yielded isometric contractions of maximal force that were accompanied by a cardiac cycle length shortening within 0.4 s from the start of stimulation. This effect was abolished by pharmacologically induced neuromuscular blockade. The cardiac cycle length shortening during paralysis reappeared after a 6- to 10-fold increase of the stimulation strength. Cutaneous (sural) nerve stimulation (15-25 microA, 100 Hz, 1 s long) elicited reflex contractions in the stimulated limb, which were also accompanied by a cardiac acceleration with similar latency. Paralysis prevented the reflex contractions and reduced the cardiac response in some cats and abolished it in others. The response reappeared in either case after a 5- to 10-fold increase of the stimulus strength. It is concluded that muscle nerve and cutaneous nerve activity both cause a similar cardiac acceleration with a latency of less than 0.4 s. The response to muscle nerve stimulation is elicited by activity in group III afferents. It is excluded that the cardiac response to nerve stimulation is secondary to a change in the respiratory pattern.

  13. Electrical stimulation in exercise training

    NASA Technical Reports Server (NTRS)

    Kroll, Walter

    1994-01-01

    Electrical stimulation has a long history of use in medicine dating back to 46 A.D. when the Roman physician Largus found the electrical discharge of torpedo fishes useful in the treatment of pain produced by headache and gout. A rival Greek physician, Dioscorides, discounted the value of the torpedo fish for headache relief but did recommend its use in the treatment of hemorrhoids. In 1745, the Leyden jar and various sized electrostatic generators were used to treat angina pectoris, epilepsy, hemiplegia, kidney stones, and sciatica. Benjamin Franklin used an electrical device to treat successfully a young woman suffering from convulsive fits. In the late 1800's battery powered hydroelectric baths were used to treat chronic inflammation of the uterus while electrified athletic supporters were advertised for the treatment of male problems. Fortunately, such an amusing early history of the simple beginnings of electrical stimulation did not prevent eventual development of a variety of useful therapeutic and rehabilitative applications of electrical stimulation. Over the centuries electrical stimulation has survived as a modality in the treatment of various medical disorders with its primary application being in the rehabilitation area. Recently, a surge of new interest in electrical stimulation has been kindled by the work of a Russian sport scientist who reported remarkable muscle strength and endurance improvements in elite athletes. Yakov Kots reported his research on electric stimulation and strength improvements in 1977 at a Canadian-Soviet Exchange Symposium held at Concordia University in Montreal. Since then an explosion of new studies has been seen in both sport science and in medicine. Based upon the reported works of Kots and the present surge of new investigations, one could be misled as to the origin of electrical stimulation as a technique to increase muscle strength. As a matter of fact, electric stimulation has been used as a technique to improve

  14. Calcitonin gene-related peptide produces skeletal muscle vasodilation following antidromic stimulation of unmyelinated afferents in the dorsal root in rats.

    PubMed

    Sato, A; Sato, Y; Shimura, M; Uchida, S

    2000-04-07

    In anesthetized rats, the contribution of calcitonin gene-related peptide (CGRP) to antidromic vasodilation of skeletal muscle blood flow (MBF) following electrical stimulation of muscle afferent was investigated by measuring biceps femoris MBF using laser Doppler flowmetry. Repetitive antidromic electrical stimulation of unmyelinated C fibers in ipsilateral dorsal roots at the 3rd-5th lumbar segments for 30 s caused an increase in MBF for 3-15 min (mean 4.5 min) without significant change in systemic arterial blood pressure. The increase in skeletal MBF started about 10 s after the onset of stimulation, and peaked at approximately 130% of the control value at about 30 s after the end of the 30 s period of stimulation. The MBF response was totally abolished by topical application of hCGRP (8-37), a CGRP receptor antagonist. It is concluded that antidromic vasodilation in skeletal muscles following stimulation of unmyelinated C afferents in dorsal roots is independent of systemic blood pressure and is mediated essentially by CGRP. It is suggested that this CGRP-related antidromic vasodilation may be important in the clinical improvement of skeletal MBF produced by physical therapy, e.g. acupuncture.

  15. Cholinergic afferents to the locus coeruleus and noradrenergic afferents to the medial septum mediate LTP-reinforcement in the dentate gyrus by stimulation of the amygdala.

    PubMed

    Bergado, Jorge A; Frey, Sabine; López, Jeffrey; Almaguer-Melian, William; Frey, Julietta U

    2007-10-01

    Transient long-term potentiation (E-LTP) can be transformed into a long-lasting LTP (L-LTP) in the dentate gyrus (DG) by behavioral stimuli with high motivational content. Previous research from our group has identified several brain structures, such as the basolateral amygdala (BLA), the locus coeruleus (LC), the medial septum (MS) and transmitters as noradrenaline (NA) and acetylcholine (ACh) that are involved in these processes. Here we have investigated the functional interplay among brain structures and systems which result in the conversion of a E-LTP into a L-LTP (reinforcement) by stimulation of the BLA (BLA-R). We used topical application of specific drugs into DG, and other targets, while following the time course of LTP induced by stimulation of the perforant pathway (PP) to study their specific contribution to BLA-R. One injection cannula, a recording electrode in the DG and stimulating electrodes in the PP and the BLA were stereotactically implanted one week before electrophysiological experiments. Topical application of atropine or propranolol into the DG blocked BLA-R in both cases, but the effect of propranolol occurred earlier, suggesting a role of NA within the DG during an intermediate stage of LTP maintenance. The injection of lidocaine into the LC abolished BLA-R indicating that the LC is part of the functional neural reinforcing system. The effect on the LC is mediated by cholinergic afferents because application of atropine into the LC produced the same effect. Injection of lidocaine inactivating the MS also abolished BLA-R. This effect was mediated by noradrenergic afferents (probably from the LC) because the application of propranolol into the MS prevented BLA-R. These findings suggest a functional loop for BLA-R involving cholinergic afferents to the LC, a noradrenergic projection from the LC to the DG and the MS, and finally, the cholinergic projection from the MS to the DG.

  16. Regenerating sprouts of axotomized cat muscle afferents express characteristic firing patterns to mechanical stimulation.

    PubMed

    Johnson, R D; Munson, J B

    1991-12-01

    1. In cats, we studied the physiological properties of regenerating sprouts of muscle afferent fibers and compared them with sprouts from cutaneous afferent fibers. 2. Muscle nerves to the triceps surae and cutaneous sural nerves were axotomized in the popliteal fossa, and the proximal ends were inserted into nerve cuffs. Six days later, we recorded action potentials from single Groups I and II muscle and mostly Group II cutaneous afferents driven by mechanostimulation of the cuff. 3. Most muscle afferent sprouts (91%) had a regular slowly adapting discharge in response to sustained mechanical displacement of the cuff, particularly to sustained stretch stimuli, whereas most cutaneous afferents (92%) did not. Muscle afferents were more likely to have a spontaneous discharge and afterdischarge. 4. Group II muscle afferent sprouts had lower stretch thresholds and a higher incidence of spontaneous discharge compared with Group I fiber sprouts, whereas Group I fibers had a higher incidence of high-frequency afterdischarge to mechanical stimuli. 5. We conclude that, 6 days after axotomy, regenerating sprouts of muscle afferents, particularly Group II afferents, have become mechanosensitive in the absence of a receptor target and exhibit physiological properties similar to those found when innervating their native muscle but significantly different from sprouts of cutaneous afferents. Expression of these native muscle afferent firing patterns after the inappropriate reinnervation of hairy skin may be due to inherent properties of the muscle afferent fiber.

  17. Heterogeneity of group Ia synapses on homonymous alpha-motoneurons as revealed by high-frequency stimulation of Ia afferent fibers.

    PubMed

    Collins, W F; Honig, M G; Mendell, L M

    1984-11-01

    Excitatory postsynaptic potentials (EPSPs) were recorded in medial gastrocnemius (MG) motoneurons following intraaxonal electrical stimulation of single spindle afferent fibers in anesthetized cats. High-frequency bursts of 32 shocks were delivered to the afferent axon and the EPSPs were averaged in the motoneuron. EPSP amplitude generally changed during the burst, in some cases increasing and in other cases decreasing, depending on the connection. Interpretation of these changes was complicated by potentiation of the initial EPSPs in the burst that occurred with the repeated bursts. The extent of the potentiation varied from connection to connection. The magnitude of facilitation or depression during a burst of standard frequency (167 Hz) was determined by comparison of EPSPs at the end of the burst with the mean EPSP obtained during low-frequency stimulation (18 Hz). Large amplitude EPSPs tended to depress, whereas the small amplitude EPSPs facilitated. Facilitation was more prevalent in motoneurons with large rheobases and depression was more often observed in small rheobase motoneurons. The use of partial correlations, which was necessary because of the inverse correlation between EPSP amplitude and motoneuron rheobase, revealed that facilitation-depression behavior during repetitive stimulation is correlated primarily with EPSP amplitude rather than with motoneuron rheobase. Acute transection of the spinal cord resulted in no change in motoneuron rheobase but considerable enlargement of mean EPSP amplitude at low frequencies of stimulation. A significant increase in the amount of depression during repetitive stimulation was noted under these conditions. These results indicate considerable heterogeneity in the response of individual connections to repetitive stimulation. We suggest that this heterogeneity results from differences in transmitter release at different connections. This heterogeneity must also have functional consequences related to susceptibility

  18. [Readjustment of the efferent activity of the scratching generator in response to stimulation of muscle afferents of the hindlimb of the decerebrate immobilized cat].

    PubMed

    Shimanskiĭ, Iu P; Baev, K V

    1987-01-01

    Rebuildings of the scratching generator activity caused by phasic electrical stimulation of ipsilateral hindlimb muscle nerves during different hindlimb positions were studied in decerebrated immobilized cats. Strong dependence of these rebuildings on the stimulation phase was observed. The character of the "scratch" cycle duration rebuilding was formed by the scratching generator tendency to bring efferent activity into such correlation with the stimulus that the stimulation moment coincided with the moment of efferent activity phase triggering. Phasic altering of the efferent activity intensity rebuilding was observed against a background of "aiming" and "scratching" activity correlation shift in the direction of strengthening activation of muscles innervated by the stimulated nerve. This rebuilding was intensified when the hindlimb deflects from the aimed position in the direction of corresponding muscles stretching. Physiological sense of "rebuilding absence phases" is discussed. It is postulated that absence of the duration and intensity changes can be achieved simultaneously only with definite correlation between phase and intensity of the afferent impulsation burst.

  19. Recordings of human polymodal single C-fiber afferents following mechanical and argon-laser heat stimulation of inflamed skin.

    PubMed

    Olausson, B

    1998-09-01

    Activity in single C-fiber afferents, whose cutaneous receptive fields were on the dorsal side of the foot (n=10), were recorded in the peroneal nerve of healthy voluntary subjects. Characterization of the fibers with respect to thresholds and field areas were made before and after cutaneous inflammation, which was induced with mustard oil. To test the nociceptive heat modality, a high-intensity argon laser was used and single 200-ms light pulses were focused onto the skin. The mechanical properties were tested with von Frey-type filaments. In the uninflamed skin, heat and mechanical stimulation activated single C-fibers in matching skin areas. The areas were all within the receptive field borders defined by electrical cutaneous stimulation. The mustard-oil-induced cutaneous inflammation was subjectively reported by the subjects as being moderately painful. In six of the units, a spontaneous activity was induced in the sample of ten previously non-active units. Before the inflammation, the 200-ms argon-laser pulse evoked a highly reproducible pattern of spike-trains. Following inflammation, this pattern was reproducible, but appeared with a significantly reduced activation rate despite the same energy being delivered to the skin both before and after the inflammation. A reduction in slope of the stimulus-response relationship was also observed after inflammation. Following inflammation, changes occurred with expansion both of the mechanical- and heat-receptive fields. The expansion was delineated by the areas defined by electrical stimulation. Following inflammation, the threshold to heat was decreased, but that to mechanical stimuli was not. No relation was detected between the threshold change and the degree of receptive-field expansion. The subjective pain reported changed following inflammation with an increase in the perceived pain in relation to the recorded action potentials, which emphasizes the importance of either an increase in sensitivity in the central

  20. Electrical stimulation to restore respiration.

    PubMed

    Creasey, G; Elefteriades, J; DiMarco, A; Talonen, P; Bijak, M; Girsch, W; Kantor, C

    1996-04-01

    Electrical stimulation has been used for over 25 years to restore breathing to patients with high quadriplegia causing respiratory paralysis and patients with central alveolar hypoventilation. Three groups have developed electrical pacing systems for long-term support of respiration in humans. These systems consist of electrodes implanted on the phrenic nerves, connected by leads to a stimulator implanted under the skin, and powered and controlled from a battery-powered transmitter outside the body. The systems differ principally in the electrode design and stimulation waveform. Approximately 1,000 people worldwide have received one of the three phrenic pacing devices, most with strongly positive results: reduced risk of tracheal problems and chronic infection, the ability to speak and smell more normally, reduced risk of accidental interruption of respiration, greater independence, and reduced costs and time for ventilatory care. For patients with partial lesions of the phrenic nerves, intercostal muscle stimulation may supplement respiration.

  1. Examination of the afferent fiber responsible for the suppression of jaw-opening reflex in heat, cold, and manual acupuncture stimulation in rats.

    PubMed

    Okada, K; Oshima, M; Kawakita, K

    1996-11-18

    The possible afferent fibers that participate in the inhibition of jaw-opening reflex (JOR) were examined using selective conduction blockade by topically applied capsaicin. Blood pressure, heart rate, and rectal temperature were monitored, and bilateral femoral nerves were denervated in thiamylal anesthetized Wistar rats. The sciatic nerves were exposed bilaterally and two cotton balls, one soaked with 1.5% capsaicin and the other with saline, were directly applied to the nerve trunk on the respective sides. We verified the conduction blockade of the compound action potentials A delta and C fibers by 1.5% capsaicin. The evoked activity of the digastric electromyography elicited by electrical stimulation of the tongue (1.5 x T, duration 200 microseconds, interval 2 ms, twin pulse, 0.2 Hz) was monitored. On the saline-treated side, the JOR was gradually inhibited by manual acupuncture stimulation of the ipsilateral hindpaw (80 s), and the effect continued after the cessation of the stimulus. This response was not obtained with the manual acupuncture stimulation on the capsaicin-treated side. Immersion of the hindpaw in hot water (53 degrees C, 40 s) induced a rapid and potent inhibition of the JOR on the saline-treated side, but not on the capsaicin-treated side. Cold water immersion (10 degrees C, 40 s) had no apparent suppressive effect on either side, but it had a rather facilitative effect on the JOR on the saline-treated side. The inhibition of the JOR was elicited by manual acupuncture stimulation of various segmental areas such as the nose, auricle, forepaw, abdomen, hindleg and hindpaw. These results suggest that the capsaicin-sensitive thin afferent fibers (A delta and C afferent fibers) mediated by receptors such as polymodal receptors are activated by manual acupuncture stimulation and that they participate in the peripheral processes that of inhibition of the JOR by diffuse noxious inhibitory controls.

  2. C-tactile afferent stimulating touch carries a positive affective value

    PubMed Central

    Pawling, Ralph; Cannon, Peter R.; McGlone, Francis P.; Walker, Susannah C.

    2017-01-01

    The rewarding sensation of touch in affiliative interactions is hypothesized to be underpinned by a specialized system of nerve fibers called C-Tactile afferents (CTs), which respond optimally to slowly moving, gentle touch, typical of a caress. However, empirical evidence to support the theory that CTs encode socially relevant, rewarding tactile information in humans is currently limited. While in healthy participants, touch applied at CT optimal velocities (1-10cm/sec) is reliably rated as subjectively pleasant, neuronopathy patients lacking large myelinated afferents, but with intact C-fibres, report that the conscious sensation elicited by stimulation of CTs is rather vague. Given this weak perceptual impact the value of self-report measures for assessing the specific affective value of CT activating touch appears limited. Therefore, we combined subjective ratings of touch pleasantness with implicit measures of affective state (facial electromyography) and autonomic arousal (heart rate) to determine whether CT activation carries a positive affective value. We recorded the activity of two key emotion-relevant facial muscle sites (zygomaticus major—smile muscle, positive affect & corrugator supercilii—frown muscle, negative affect) while participants evaluated the pleasantness of experimenter administered stroking touch, delivered using a soft brush, at two velocities (CT optimal 3cm/sec & CT non-optimal 30cm/sec), on two skin sites (CT innervated forearm & non-CT innervated palm). On both sites, 3cm/sec stroking touch was rated as more pleasant and produced greater heart rate deceleration than 30cm/sec stimulation. However, neither self-report ratings nor heart rate responses discriminated stimulation on the CT innervated arm from stroking of the non-CT innervated palm. In contrast, significantly greater activation of the zygomaticus major (smiling muscle) was seen specifically to CT optimal, 3cm/sec, stroking on the forearm in comparison to all other

  3. Evoked Electromyographically Controlled Electrical Stimulation

    PubMed Central

    Hayashibe, Mitsuhiro

    2016-01-01

    Time-variant muscle responses under electrical stimulation (ES) are often problematic for all the applications of neuroprosthetic muscle control. This situation limits the range of ES usage in relevant areas, mainly due to muscle fatigue and also to changes in stimulation electrode contact conditions, especially in transcutaneous ES. Surface electrodes are still the most widely used in noninvasive applications. Electrical field variations caused by changes in the stimulation contact condition markedly affect the resulting total muscle activation levels. Fatigue phenomena under functional electrical stimulation (FES) are also well known source of time-varying characteristics coming from muscle response under ES. Therefore, it is essential to monitor the actual muscle state and assess the expected muscle response by ES so as to improve the current ES system in favor of adaptive muscle-response-aware FES control. To deal with this issue, we have been studying a novel control technique using evoked electromyography (eEMG) signals to compensate for these muscle time-variances under ES for stable neuroprosthetic muscle control. In this perspective article, I overview the background of this topic and highlight important points to be aware of when using ES to induce the desired muscle activation regardless of the time-variance. I also demonstrate how to deal with the common critical problem of ES to move toward robust neuroprosthetic muscle control with the Evoked Electromyographically Controlled Electrical Stimulation paradigm. PMID:27471448

  4. Electrical stimulation of mechanoreceptors

    NASA Astrophysics Data System (ADS)

    Echenique, A. M.; Graffigna, J. P.

    2011-12-01

    Within the field of Rehabilitation Engineering, this work is aimed at identifying the optimal parameters of electric current stimulus which activate the nervous axons of mecanoreceptors found in the fingertip, allowing, this way, to resemble tactile senses. These sensorial feelings can be used by aiding technological means, namely, the sensorial substitution technology, in an attempt to render information to blind people through the tactile sense. The physical pressure on sensorial areas (fingertips) used for reading activities through the Braille System is the main effect that is imitated and studied in this research work. An experimental aiding prototype for Braille reading research has been developed and tested with blinds and reduced vision people, with highly satisfactory results.

  5. Vagal nerve stimulation activates vagal afferent fibers that reduce cardiac efferent parasympathetic effects

    PubMed Central

    Yamakawa, Kentaro; Rajendran, Pradeep S.; Takamiya, Tatsuo; Yagishita, Daigo; So, Eileen L.; Mahajan, Aman; Shivkumar, Kalyanam

    2015-01-01

    Vagal nerve stimulation (VNS) has been shown to have antiarrhythmic effects, but many of these benefits were demonstrated in the setting of vagal nerve decentralization. The purpose of this study was to evaluate the role of afferent fiber activation during VNS on efferent control of cardiac hemodynamic and electrophysiological parameters. In 37 pigs a 56-electrode sock was placed over the ventricles to record local activation recovery intervals (ARIs), a surrogate of action potential duration. In 12 of 37 animals atropine was given systemically. Right and left VNS were performed under six conditions: both vagal trunks intact (n = 25), ipsilateral right (n = 11), ipsilateral left (n = 14), contralateral right (n = 7), contralateral left (n = 10), and bilateral (n = 25) vagal nerve transection (VNTx). Unilateral VNTx significantly affected heart rate, PR interval, Tau, and global ARIs. Right VNS after ipsilateral VNTx had augmented effects on hemodynamic parameters and increase in ARI, while subsequent bilateral VNTx did not significantly modify this effect (%change in ARI in intact condition 2.2 ± 0.9% vs. ipsilateral VNTx 5.3 ± 1.7% and bilateral VNTx 5.3 ± 0.8%, P < 0.05). Left VNS after left VNTx tended to increase its effects on hemodynamics and ARI response (P = 0.07), but only after bilateral VNTx did these changes reach significance (intact 1.1 ± 0.5% vs. ipsilateral VNTx 3.6 ± 0.7% and bilateral VNTx 6.6 ± 1.6%, P < 0.05 vs. intact). Contralateral VNTx did not modify VNS response. The effect of atropine on ventricular ARI was similar to bilateral VNTx. We found that VNS activates afferent fibers in the ipsilateral vagal nerve, which reflexively inhibit cardiac parasympathetic efferent electrophysiological and hemodynamic effects. PMID:26371172

  6. The facilitation of motor actions by acoustic and electric stimulation.

    PubMed

    Marinovic, Welber; Milford, Magdalene; Carroll, Timothy; Riek, Stephan

    2015-12-01

    The presentation of a loud acoustic stimulus during the preparation of motor actions can both speed movement initiation and increase response vigor. Several recent studies have explored this phenomenon as a means to investigate the mechanisms and neural correlates of movement preparation. Here, we sought to determine the generality of this effect across sensory modalities, and in particular whether unexpected somatosensory stimulation can facilitate movements in a manner similar to loud sounds. We show that electric and acoustic stimuli can be similarly effective in inducing the early release of motor actions, in both reaction time and anticipatory timing tasks. Consistent with recent response activation models of motor preparation, we also demonstrate that increasing the intensity of electric stimuli induces both progressive decreases in reaction time and increases in response vigor. Additionally, we show that the early release of motor actions can be induced by electric stimuli targeting predominantly either muscle afferents or skin afferents. Finally, we show that simultaneous acoustic and electric stimulation leads to earlier releases of anticipatory actions than either unimodal stimulus. These findings may lead to new avenues for experimental and clinical exploitation of the effects of accessory sensory information on movement preparation and initiation.

  7. The Electrical Stimulation Modifies the Cerebral Function

    NASA Astrophysics Data System (ADS)

    Rocha, Luisa Lilia; López-Meraz, María Leonor; Cuéllar-Herrera, Manola; Neri-Bazán., Leticia

    2002-08-01

    Electrical stimulation has been used for therapeuthic purposes. In this review, we present the clinical and scientific bases for using electrical stimulation as a treatment for pharmacological refractory epilepsy. We also describe results in receptors of inhibitory neurotransmitters obtained in rat brain with or without epilepsy, undergoing brain stimulation. Brain electrical stimulation may improve our understanding of brain function and neuroplasticity.

  8. Electrical stimulation and motor recovery.

    PubMed

    Young, Wise

    2015-01-01

    In recent years, several investigators have successfully regenerated axons in animal spinal cords without locomotor recovery. One explanation is that the animals were not trained to use the regenerated connections. Intensive locomotor training improves walking recovery after spinal cord injury (SCI) in people, and >90% of people with incomplete SCI recover walking with training. Although the optimal timing, duration, intensity, and type of locomotor training are still controversial, many investigators have reported beneficial effects of training on locomotor function. The mechanisms by which training improves recovery are not clear, but an attractive theory is available. In 1949, Donald Hebb proposed a famous rule that has been paraphrased as "neurons that fire together, wire together." This rule provided a theoretical basis for a widely accepted theory that homosynaptic and heterosynaptic activity facilitate synaptic formation and consolidation. In addition, the lumbar spinal cord has a locomotor center, called the central pattern generator (CPG), which can be activated nonspecifically with electrical stimulation or neurotransmitters to produce walking. The CPG is an obvious target to reconnect after SCI. Stimulating motor cortex, spinal cord, or peripheral nerves can modulate lumbar spinal cord excitability. Motor cortex stimulation causes long-term changes in spinal reflexes and synapses, increases sprouting of the corticospinal tract, and restores skilled forelimb function in rats. Long used to treat chronic pain, motor cortex stimuli modify lumbar spinal network excitability and improve lower extremity motor scores in humans. Similarly, epidural spinal cord stimulation has long been used to treat pain and spasticity. Subthreshold epidural stimulation reduces the threshold for locomotor activity. In 2011, Harkema et al. reported lumbosacral epidural stimulation restores motor control in chronic motor complete patients. Peripheral nerve or functional electrical

  9. Visceral Nociceptive Afferent Facilitates Reaction of Subnucleus Reticularis Dorsalis to Acupoint Stimulation in Rats

    PubMed Central

    Li, Liang; Yu, Lingling; Rong, Peijing; Ben, Hui; Li, Xia; Zhu, Bing; Chen, Rixin

    2013-01-01

    Objective. To explore the area and sensitization variance of acupoint when internal organs are under pathological condition. To observe quantity-effect variance of subnucleus reticularis dorsalis (SRD) to electroacupuncture under both physiological and pathological conditions. To explain medulla oblongata mechanism of acupoint sensitization. Method. Mustard oil was imported into colon and rectum of 20 male SD rats in order to observe its influence on acupoint sensitization. SRD neuron activity was recorded. Visceral nociceptive stimulus was generated by colorectal distension (CRD). Quantity-effect variance of neuron activity to electroacupuncture to “Zusanli-Shangjuxu” area both before and after CRD was observed. Paired t-test is used for cross-group comparison; P < 0.05 is deemed as of statistical differences. Result. Visceral inflammation could facilitate SRD neuron activity to acupoint stimulation. Visceral nociceptive afference could enhance neuron activity to acupoint acupuncture. Wide dynamic range (WDR) neuron activity caused by electroacupuncture increased when visceral nociception increased. Conclusion. The size and function of the acupoints comply with the functionality of the internal organs. The sensitive degree of acupoints changed according to malfunction of internal organs. PMID:23762171

  10. Single well electric oil stimulation

    SciTech Connect

    Perkins, Th. K.

    1985-06-11

    A single well method and apparatus for electrically applying heat and stimulating is comprised of a relatively lower surface area formation electrode and relatively high surface area overburden electrode extending downward into the borehole past low resistivity water zones. This long overburden electrode may be formed of nonmagnetic metal to reduce hysteresis losses in the electrode. This improved single well system causes most of power to be dissipated in the oil pay zone and thereby renders single well production economical.

  11. Neuromuscular Electrical Stimulation for Skeletal Muscle Function

    PubMed Central

    Doucet, Barbara M.; Lam, Amy; Griffin, Lisa

    2012-01-01

    Lack of neural innervation due to neurological damage renders muscle unable to produce force. Use of electrical stimulation is a medium in which investigators have tried to find a way to restore movement and the ability to perform activities of daily living. Different methods of applying electrical current to modify neuromuscular activity are electrical stimulation (ES), neuromuscular electrical stimulation (NMES), transcutaneous electrical nerve stimulation (TENS), and functional electrical stimulation (FES). This review covers the aspects of electrical stimulation used for rehabilitation and functional purposes. Discussed are the various parameters of electrical stimulation, including frequency, pulse width/duration, duty cycle, intensity/amplitude, ramp time, pulse pattern, program duration, program frequency, and muscle group activated, and how they affect fatigue in the stimulated muscle. PMID:22737049

  12. Efferents and afferents in an intact muscle nerve: background activity and effects of sural nerve stimulation in the cat.

    PubMed

    Bessou, P; Joffroy, M; Pagès, B

    1981-11-01

    1. The background activity was observed in gamma and alpha efferent fibres and in group I and II fibres innervating the muscle gastrocnemius lateralis or medialis. The reflex effects of ipsilateral and contralateral sural nerve stimulations on the muscle efferents were analysed together with their consequences upon the afferents of the same muscle. The observations were made in the decerebrated cat without opening the neural loops between the muscle and the spinal cord.2. The multi-unit discharges of each category of fibres were obtained, on line, by an original electronic device (Joffroy, 1975, 1980) that sorted the action potentials from the whole electrical activity of a small branch of gastrocnemius lateralis or medialis nerve according to the direction and velocity of propagation of the potentials.3. The small nerve may be regarded as a representative sample of different functional groups of fibres conducting faster than 12 m.sec(-1) and supplying gastrocnemius muscles.4. Some gamma efferents were always tonically firing except when a transient flaccid state developed. Usually the alpha efferents were silent, probably because the muscle was fixed close to the minimal physiological length.5. Separate and selective stimulations of Abeta, Adelta and C fibres of ipsilateral and contralateral sural nerve showed that each group could induce the excitation of gamma neurones. The reciprocal inhibition period of alpha efferents during a flexor reflex was only once accompanied by a small decrease in gamma-firing.6. The reflex increase of over-all frequency of gamma efferents resulted from an increased firing rate of tonic gamma neurones and from the recruitment of gamma neurones previously silent. When the gamma efferents in the small nerve naturally occurred in two subgroups, the slower-conducting subgroup (mainly composed of tonic gamma axons) was activated before the faster-conducting subgroup (mostly composed by gamma axons with no background discharge). Some rare

  13. Vasodilatation in hyperalgesic rat skin evoked by stimulation of afferent A beta-fibers: further evidence for a role of dorsal root reflexes in allodynia.

    PubMed

    Garcia-Nicas, E; Laird, J M; Cervero, F

    2001-12-01

    In areas of secondary hyperalgesia, innocuous mechanical stimuli evoke pain (allodynia). We have proposed that this is produced by a central pre-synaptic interaction whereby A beta-fibers evoke spike activity (dorsal root reflexes) in nociceptive afferents (Pain, 68 (1996) 13). This activity should conduct centrally, evoking allodynia, and peripherally, evoking neurogenic vasodilatation. Here we tested this hypothesis by examining the effects of electrical stimulation of A beta-fibers on cutaneous blood flow before and after producing secondary hyperalgesia in anesthetized rats. Cutaneous blood flow was recorded in the hind paw skin innervated by the sural nerve using a laser Doppler flowmeter. The sural nerve was prepared for electrical stimulation, and the evoked activity was recorded from the sciatic nerve in continuity. Electrical stimulation (1 Hz, 4 x 0.2 ms pulses, 20 s) was applied to the sural nerve at 2T (A beta-fibers only) and 4T and 6T (A beta + A delta-fibers). Flux was recorded at baseline and after capsaicin or mustard oil application outside the sural nerve territory. The effects of intravenous administration of the calcitonin gene-related peptide (CGRP) receptor antagonist, alpha-CGRP(8-37), or of section of the sciatic nerve or of the L4-L6 dorsal roots were examined. Selective activation of the sural nerve A beta-fibers reliably evoked increases in cutaneous blood flow close to areas of chemical irritation or skin damage. A beta-fiber-evoked vasodilatation was abolished by sciatic nerve or dorsal root section and had a spatial arrangement and optimal stimulation pattern suggesting a central synaptic interaction similar to that responsible for dorsal root reflexes. The flux increases were dose-dependently and reversibly inhibited by alpha-CGRP(8-37), indicating that the A beta-fiber-evoked vasodilatation resulted from the antidromic activation of nociceptive cutaneous afferent fibers. These results support our hypothesis by showing activation of

  14. Minocycline inhibits the enhancement of antidromic primary afferent stimulation-evoked vasodilation following intradermal capsaicin injection.

    PubMed

    Gong, Kerui; Yue, Yue; Zou, Xiaoju; Li, Dingge; Lin, Qing

    2010-09-27

    Neurogenic inflammation is induced by inflammatory mediators released in peripheral tissue from primary afferent nociceptors. Our previous studies suggest that neurogenic inflammation induced by intradermal injection of capsaicin results from the enhancement of dorsal root reflexes (DRRs), which involve antidromic activation of dorsal root ganglion (DRG) neurons. Numerous studies have reported the important role of glial modulation in pain. However, it remains unclear whether glial cells participate in the process of neurogenic inflammation-induced pain. Here we tested the role of DRG satellite glial cells (SGCs) in this process in anesthetized rats by administration of a glial inhibitor, minocycline. Electrical stimuli (ES, frequency 10 Hz; duration 1 ms; strength 3 mA) were applied to the cut distal ends of the L4-5 dorsal roots. The stimuli evoked antidromic action potentials designed to mimic DRRs. Local cutaneous blood flow in the hindpaw was measured using a Doppler flow meter. Antidromic ES for 10 min evoked a significant vasodilation that could be inhibited dose-dependently by local administration of the calcitonin gene-related peptide receptor antagonist, CGRP8-37. Pretreatment with capsaicin intradermally injected into the hindpaw 2h before the ES enhanced greatly the vasodilation evoked by antidromic ES, and this enhancement could be reversed by minocycline pretreatment. Our findings support the view that neurogenic inflammation following capsaicin injection involves antidromic activation of DRG neurons via the generation of DRRs. Inhibition of neurogenic inflammation by minocycline is suggested to be associated with its inhibitory effect on SGCs that are possibly activated following capsaicin injection.

  15. Sensations evoked by microstimulation of single mechanoreceptive afferents innervating the human face and mouth.

    PubMed

    Trulsson, M; Essick, G K

    2010-04-01

    Intraneural microneurography and microstimulation were performed on single afferent axons in the inferior alveolar and lingual nerves innervating the face, teeth, labial, or oral mucosa. Using natural mechanical stimuli, 35 single mechanoreceptive afferents were characterized with respect to unit type [fast adapting type I (FA I), FA hair, slowly adapting type I and II (SA I and SA II), periodontal, and deep tongue units] as well as size and shape of the receptive field. All afferents were subsequently microstimulated with pulse trains at 30 Hz lasting 1.0 s. Afferents recordings whose were stable thereafter were also tested with single pulses and pulse trains at 5 and 60 Hz. The results revealed that electrical stimulation of single FA I, FA hair, and SA I afferents from the orofacial region can evoke a percept that is spatially matched to the afferent's receptive field and consistent with the afferent's response properties as observed on natural mechanical stimulation. Stimulation of FA afferents typically evoked sensations that were vibratory in nature; whereas those of SA I afferents were felt as constant pressure. These afferents terminate superficially in the orofacial tissues and seem to have a particularly powerful access to perceptual levels. In contrast, microstimulation of single periodontal, SA II, and deep tongue afferents failed to evoke a sensation that matched the receptive field of the afferent. These afferents terminate more deeply in the tissues, are often active in the absence of external stimulation, and probably access perceptual levels only when multiple afferents are stimulated. It is suggested that the spontaneously active afferents that monitor tension in collagen fibers (SA II and periodontal afferents) may have the role to register the mechanical state of the soft tissues, which has been hypothesized to help maintain the body's representation in the central somatosensory system.

  16. Evoked Pain Analgesia in Chronic Pelvic Pain Patients using Respiratory-gated Auricular Vagal Afferent Nerve Stimulation

    PubMed Central

    Napadow, Vitaly; Edwards, Robert R; Cahalan, Christine M; Mensing, George; Greenbaum, Seth; Valovska, Assia; Li, Ang; Kim, Jieun; Maeda, Yumi; Park, Kyungmo; Wasan, Ajay D.

    2012-01-01

    Objective Previous Vagus Nerve Stimulation (VNS) studies have demonstrated anti-nociceptive effects, and recent non-invasive approaches; termed transcutaneous-VNS, or t-VNS, have utilized stimulation of the auricular branch of the vagus nerve in the ear. The dorsal medullary vagal system operates in tune with respiration, and we propose that supplying vagal afferent stimulation gated to the exhalation phase of respiration can optimize t-VNS. Design counterbalanced, crossover study. Patients patients with chronic pelvic pain (CPP) due to endometriosis in a specialty pain clinic. Interventions/Outcomes We evaluated evoked pain analgesia for Respiratory-gated Auricular Vagal Afferent Nerve Stimulation (RAVANS) compared with Non-Vagal Auricular Stimulation (NVAS). RAVANS and NVAS were evaluated in separate sessions spaced at least one week apart. Outcome measures included deep tissue pain intensity, temporal summation of pain, and anxiety ratings, which were assessed at baseline, during active stimulation, immediately following stimulation, and 15 minutes after stimulus cessation. Results RAVANS demonstrated a trend for reduced evoked pain intensity and temporal summation of mechanical pain, and significantly reduced anxiety in N=15 CPP patients, compared to NVAS, with moderate to large effect sizes (eta2>0.2). Conclusion Chronic pain disorders such as CPP are in great need of effective, non-pharmacological options for treatment. RAVANS produced promising anti-nociceptive effects for QST outcomes reflective of the noted hyperalgesia and central sensitization in this patient population. Future studies should evaluate longer-term application of RAVANS to examine its effects on both QST outcomes and clinical pain. PMID:22568773

  17. Decreased afferent excitability contributes to synaptic depression during high-frequency stimulation in hippocampal area CA1.

    PubMed

    Kim, Eunyoung; Owen, Benjamin; Holmes, William R; Grover, Lawrence M

    2012-10-01

    Long-term potentiation (LTP) is often induced experimentally by continuous high-frequency afferent stimulation (HFS), typically at 100 Hz for 1 s. Induction of LTP requires postsynaptic depolarization and voltage-dependent calcium influx. Induction is more effective if the same number of stimuli are given as a series of short bursts rather than as continuous HFS, in part because excitatory postsynaptic potentials (EPSPs) become strongly depressed during HFS, reducing postsynaptic depolarization. In this study, we examined mechanisms of EPSP depression during HFS in area CA1 of rat hippocampal brain slices. We tested for presynaptic terminal vesicle depletion by examining minimal stimulation-evoked excitatory postsynaptic currents (EPSCs) during 100-Hz HFS. While transmission failures increased, consistent with vesicle depletion, EPSC latencies also increased during HFS, suggesting a decrease in afferent excitability. Extracellular recordings of Schaffer collateral fiber volleys confirmed a decrease in afferent excitability, with decreased fiber volley amplitudes and increased latencies during HFS. To determine the mechanism responsible for fiber volley changes, we recorded antidromic action potentials in single CA3 pyramidal neurons evoked by stimulating Schaffer collateral axons. During HFS, individual action potentials decreased in amplitude and increased in latency, and these changes were accompanied by a large increase in the probability of action potential failure. Time derivative and phase-plane analyses indicated decreases in both axon initial segment and somato-dendritic components of CA3 neuron action potentials. Our results indicate that decreased presynaptic axon excitability contributes to depression of excitatory synaptic transmission during HFS at synapses between Schaffer collaterals and CA1 pyramidal neurons.

  18. Braille line using electrical stimulation

    NASA Astrophysics Data System (ADS)

    Puertas, A.; Purés, P.; Echenique, A. M.; Ensinck, J. P. Graffigna y. G.

    2007-11-01

    Conceived within the field of Rehabilitation Technologies for visually impaired persons, the present work aims at enabling the blind user to read written material by means of a tactile display. Once he is familiarized to operate this system, the user will be able to achieve greater performance in study, academic and job activities, thus achieving a rapid and easier social inclusion. The devise accepts any kind of text that is computer-loadable (documents, books, Internet information, and the like) which, through digital means, can be read as Braille text on the pad. This tactile display is composed of an electrodes platform that simulate, through stimulation the writing/reading Braille characters. In order to perceive said characters in similar way to the tactile feeling from paper material, the skin receptor of fingers are stimulated electrically so as to simulate the same pressure and depressions as those of the paper-based counterpart information. Once designed and developed, the display was tested with blind subjects, with relatively satisfactory results. As a continuing project, this prototype is currently being improved as regards.

  19. Bulbospinal inhibition of PAD elicited by stimulation of afferent and motor axons in the isolated frog spinal cord and brainstem.

    PubMed

    González, H; Jiménez, I; Rudomin, P

    1992-01-01

    1. In the isolated spinal cord and brainstem of the frog, stimulation of the brainstem (BS) with trains of 3-4 pulses at 60-400 Hz produced dorsal root potentials (DRPs). The lowest threshold sites eliciting DRPs were located at the level of the obex up to about 2.5 mm rostrally, 0.5-1.2 mm laterally, between 0.5 and 1.6 mm depth. This region corresponds to the bulbar reticular formation (RF). 2. Stimulation of the RF with strengths below those required to produce DRPs, very effectively inhibited the DRPs produced by stimulation of a neighboring dorsal root (DR-DRPs) as well as the DRPs produced by antidromic stimulation of the central end of motor nerves (VR-DRPs). The inhibition was detectable 20 ms after the first pulse of the conditioning train, attained maximal values between 50 and 100 ms and lasted more than 250 ms. 3. Stimulation of the bulbar RF increased the negative response (N1 response) produced in the motor pool by antidromic activation of motoneurons. The time course of the facilitation of the N1 response resembled that of the reticularly-induced inhibition of the VR-DRPs and DR-DRPs. 4. The present series of observations supports the existence of reticulo-spinal pathways that are able to inhibit the depolarization elicited in afferent fibers by stimulation of other afferent fibers or by antidromic activation of motor axons. This inhibition appears to be exerted on the PAD mediating interneurons and is envisaged as playing an important role in motor control.

  20. Electrical Stimulation Enhances Reinnervation After Nerve Injury

    PubMed Central

    2015-01-01

    Electrical muscle stimulation following peripheral nerve injury has been a controversial method of treatment due primarily to the inconsistent literature surrounding it. In this presentation transcript I outline ongoing experiments investigating a clinically translatable daily muscle stimulation paradigm in rats following nerve injury. Results show that reinnervation of muscle and functional behavioural metrics are enhanced with daily stimulation with upregulation of intramuscular neurotrophic factors as a potential mechanism. In addition, the impact of stimulation on terminal sprouting, a mentioned negative aspect of electrical muscle stimulation, was a minor contributor to long term functional reinnervation of stimulated muscles in our studies. PMID:26913163

  1. A computational model for estimating recruitment of primary afferent fibers by intraneural stimulation in the dorsal root ganglia

    NASA Astrophysics Data System (ADS)

    Bourbeau, D. J.; Hokanson, J. A.; Rubin, J. E.; Weber, D. J.

    2011-10-01

    Primary afferent microstimulation has been proposed as a method for activating cutaneous and muscle afferent fibers to restore tactile and proprioceptive feedback after limb loss or peripheral neuropathy. Large populations of primary afferent fibers can be accessed directly by implanting microelectrode arrays in the dorsal root ganglia (DRG), which provide a compact and stable target for stimulating a diverse group of sensory fibers. To gain insight into factors affecting the number and types of primary afferents activated, we developed a computational model that simulates the recruitment of fibers in the feline L7 DRG. The model comprises two parts. The first part is a single-fiber model used to describe the current-distance relation and was based on the McIntyre-Richardson-Grill model for excitability. The second part uses the results of the singe-fiber model and published data on fiber size distributions to predict the probability of recruiting a given number of fibers as a function of stimulus intensity. The range of intensities over which exactly one fiber was recruited was approximately 0.5-5 µA (0.1-1 nC per phase); the stimulus intensity at which the probability of recruiting exactly one fiber was maximized was 2.3 µA. However, at 2.3 µA, it was also possible to recruit up to three fibers, albeit with a lower probability. Stimulation amplitudes up to 6 µA were tested with the population model, which showed that as the amplitude increased, the number of fibers recruited increased exponentially. The distribution of threshold amplitudes predicted by the model was similar to that previously reported by in vivo experimentation. Finally, the model suggested that medium diameter fibers (7.3-11.5 µm) may be recruited with much greater probability than large diameter fibers (12.8-16 µm). This model may be used to efficiently test a range of stimulation parameters and nerve morphologies to complement results from electrophysiology experiments and to aid in the

  2. Optogenetic versus electrical stimulation of dopamine terminals in the nucleus accumbens reveals local modulation of presynaptic release

    PubMed Central

    Melchior, James R.; Ferris, Mark J.; Stuber, Garret D.; Riddle, David R.; Jones, Sara R.

    2015-01-01

    The nucleus accumbens is highly heterogeneous, integrating regionally distinct afferent projections and accumbal interneurons, resulting in diverse local microenvironments. Dopamine (DA) neuron terminals similarly express a heterogeneous collection of terminal receptors that modulate DA signaling. Cyclic voltammetry is often used to probe DA terminal dynamics in brain slice preparations; however, this method traditionally requires electrical stimulation to induce DA release. Electrical stimulation excites all of the neuronal processes in the stimulation field, potentially introducing simultaneous, multi-synaptic modulation of DA terminal release. We used optogenetics to selectively stimulate DA terminals and used voltammetry to compare DA responses from electrical and optical stimulation of the same area of tissue around a recording electrode. We found that with multiple pulse stimulation trains, optically stimulated DA release increasingly exceeded that of electrical stimulation. Furthermore, electrical stimulation produced inhibition of DA release across longer duration stimulations. The GABAB antagonist, CGP 55845, increased electrically stimulated DA release significantly more than light stimulated release. The nicotinic acetylcholine receptor antagonist, dihydro-β-erythroidine hydrobromide, inhibited single pulse electrically stimulated DA release while having no effect on optically stimulated DA release. Our results demonstrate that electrical stimulation introduces local multi-synaptic modulation of DA release that is absent with optogenetically targeted stimulation. PMID:26011081

  3. [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.

  4. Vomiting Center reanalyzed: An electrical stimulation study

    NASA Technical Reports Server (NTRS)

    Miller, A. D.; Wilson, V. J.

    1982-01-01

    Electrical stimulation of the brainstem of 15 decerebrate cats produced stimulus-bound vomiting in only 4 animals. Vomiting was reproducible in only one cat. Effective stimulating sites were located in the solitary tract and reticular formation. Restricted localization of a vomiting center, stimulation of which evoked readily reproducible results, could not be obtained.

  5. Electrical stimulation to accelerate wound healing

    PubMed Central

    Thakral, Gaurav; LaFontaine, Javier; Najafi, Bijan; Talal, Talal K.; Kim, Paul; Lavery, Lawrence A.

    2013-01-01

    Background There are several applications of electrical stimulation described in medical literature to accelerate wound healing and improve cutaneous perfusion. This is a simple technique that could be incorporated as an adjunctive therapy in plastic surgery. The objective of this review was to evaluate the results of randomized clinical trials that use electrical stimulation for wound healing. Method We identified 21 randomized clinical trials that used electrical stimulation for wound healing. We did not include five studies with treatment groups with less than eight subjects. Results Electrical stimulation was associated with faster wound area reduction or a higher proportion of wounds that healed in 14 out of 16 wound randomized clinical trials. The type of electrical stimulation, waveform, and duration of therapy vary in the literature. Conclusion Electrical stimulation has been shown to accelerate wound healing and increase cutaneous perfusion in human studies. Electrical stimulation is an adjunctive therapy that is underutilized in plastic surgery and could improve flap and graft survival, accelerate postoperative recovery, and decrease necrosis following foot reconstruction. PMID:24049559

  6. Limb venous distension evokes sympathetic activation via stimulation of the limb afferents in humans.

    PubMed

    Cui, Jian; McQuillan, Patrick M; Blaha, Cheryl; Kunselman, Allen R; Sinoway, Lawrence I

    2012-08-15

    We have recently shown that a saline infusion in the veins of an arterially occluded human forearm evokes a systemic response with increases in muscle sympathetic nerve activity (MSNA) and blood pressure. In this report, we examined whether this response was a reflex that was due to venous distension. Blood pressure (Finometer), heart rate, and MSNA (microneurography) were assessed in 14 young healthy subjects. In the saline trial (n = 14), 5% forearm volume normal saline was infused in an arterially occluded arm. To block afferents in the limb, 90 mg of lidocaine were added to the same volume of saline in six subjects during a separate visit. To examine whether interstitial perfusion of normal saline alone induced the responses, the same volume of albumin solution (5% concentration) was infused in 11 subjects in separate studies. Lidocaine abolished the MSNA and blood pressure responses seen with saline infusion. Moreover, compared with the saline infusion, an albumin infusion induced a larger (MSNA: Δ14.3 ± 2.7 vs. Δ8.5 ± 1.3 bursts/min, P < 0.01) and more sustained MSNA and blood pressure responses. These data suggest that venous distension activates afferent nerves and evokes a powerful systemic sympathoexcitatory reflex. We posit that the venous distension plays an important role in evoking the autonomic adjustments seen with postural stress in human subjects.

  7. High Frequency Stimulation of the Subthalamic Nucleus Leads to Presynaptic GABA(B)-Dependent Depression of Subthalamo-Nigral Afferents

    PubMed Central

    Dvorzhak, Anton; Gertler, Christoph; Harnack, Daniel; Grantyn, Rosemarie

    2013-01-01

    Patients with akinesia benefit from chronic high frequency stimulation (HFS) of the subthalamic nucleus (STN). Among the mechanisms contributing to the therapeutic success of HFS-STN might be a suppression of activity in the output region of the basal ganglia. Indeed, recordings in the substantia nigra pars reticulata (SNr) of fully adult mice revealed that HFS-STN consistently produced a reduction of compound glutamatergic excitatory postsynaptic currents at a time when the tetrodotoxin-sensitive components of the local field potentials had already recovered after the high frequency activation. These observations suggest that HFS-STN not only alters action potential conduction on the way towards the SNr but also modifies synaptic transmission within the SNr. A classical conditioning-test paradigm was then designed to better separate the causes from the indicators of synaptic depression. A bipolar platinum-iridium macroelectrode delivered conditioning HFS trains to a larger group of fibers in the STN, while a separate high-ohmic glass micropipette in the rostral SNr provided test stimuli at minimal intensity to single fibers. The conditioning-test interval was set to 100 ms, i.e. the time required to recover the excitability of subthalamo-nigral axons after HFS-STN. The continuity of STN axons passing from the conditioning to the test sites was examined by an action potential occlusion test. About two thirds of the subthalamo-nigral afferents were occlusion-negative, i.e. they were not among the fibers directly activated by the conditioning STN stimulation. Nonetheless, occlusion-negative afferents exhibited signs of presynaptic depression that could be eliminated by blocking GABA(B) receptors with CGP55845 (1 µM). Further analysis of single fiber-activated responses supported the proposal that the heterosynaptic depression of synaptic glutamate release during and after HFS-STN is mainly caused by the tonic release of GABA from co-activated striato

  8. Electrical brain stimulation for epilepsy.

    PubMed

    Fisher, Robert S; Velasco, Ana Luisa

    2014-05-01

    Neurostimulation enables adjustable and reversible modulation of disease symptoms, including those of epilepsy. Two types of brain neuromodulation, comprising anterior thalamic deep brain stimulation and responsive neurostimulation at seizure foci, are supported by Class I evidence of effectiveness, and many other sites in the brain have been targeted in small trials of neurostimulation therapy for seizures. Animal studies have mainly assisted in the identification of potential neurostimulation sites and parameters, but much of the clinical work is only loosely based on fundamental principles derived from the laboratory, and the mechanisms by which brain neurostimulation reduces seizures remain poorly understood. The benefits of stimulation tend to increase over time, with maximal effect seen typically 1-2 years after implantation. Typical reductions of seizure frequency are approximately 40% acutely, and 50-69% after several years. Seizure intensity might also be reduced. Complications from brain neurostimulation are mainly associated with the implantation procedure and hardware, including stimulation-related paraesthesias, stimulation-site infections, electrode mistargeting and, in some patients, triggered seizures or even status epilepticus. Further preclinical and clinical experience with brain stimulation surgery should lead to improved outcomes by increasing our understanding of the optimal surgical candidates, sites and parameters.

  9. Reflex inhibition of normal cramp following electrical stimulation of the muscle tendon.

    PubMed

    Khan, Serajul I; Burne, John A

    2007-09-01

    Muscle cramp was induced in one head of the gastrocnemius muscle (GA) in eight of thirteen subjects using maximum voluntary contraction when the muscle was in the shortened position. Cramp in GA was painful, involuntary, and localized. Induction of cramp was indicated by the presence of electromyographic (EMG) activity in one head of GA while the other head remained silent. In all cramping subjects, reflex inhibition of cramp electrical activity was observed following Achilles tendon electrical stimulation and they all reported subjective relief of cramp. Thus muscle cramp can be inhibited by stimulation of tendon afferents in the cramped muscle. When the inhibition of cramp-generated EMG and voluntary EMG was compared at similar mean EMG levels, the area and timing of the two phases of inhibition (I(1), I(2)) did not differ significantly. This strongly suggests that the same reflex pathway was the source of the inhibition in both cases. Thus the cramp-generated EMG is also likely to be driven by spinal synaptic input to the motorneurons. We have found that the muscle conditions that appear necessary to facilitate cramp, a near to maximal contraction of the shortened muscle, are also the conditions that render the inhibition generated by tendon afferents ineffective. When the strength of tendon inhibition in cramping subjects was compared with that in subjects that failed to cramp, it was found to be significantly weaker under the same experimental conditions. It is likely that reduced inhibitory feedback from tendon afferents has an important role in generating cramp.

  10. Effect of Paired-Pulse Electrical Stimulation on the Activity of Cortical Circuits

    PubMed Central

    Saito, Kei; Onishi, Hideaki; Miyaguchi, Shota; Kotan, Shinichi; Fujimoto, Shuhei

    2015-01-01

    Objective: We investigated the transient effect of short-duration paired-pulse electrical stimulation (ppES) on corticospinal excitability and the after-effect of long-duration ppES on excitability, short-latency afferent inhibition (SAI), and afferent facilitation (AF). Methods: A total of 28 healthy subjects participated in two different experiments. In Experiment 1, motor-evoked potentials (MEPs) were measured in the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles before and immediately after short-duration ppES (5 s) at various inter-pulse intervals (2, 3, 4, 5, 6, 7, 10, 15, 20, and 30 ms). In Experiment 2, MEPs, SAI, and AF were measured before, immediately, and 20 and 40 min after long-duration ppES (20 min, inter-pulse interval of 5 and 15 ms) and peripheral electrical stimulation (20 min, 10 and 20 Hz). Results: Short-duration ppES with inter-pulse intervals of 5 and 20 ms significantly increased MEP measured in APB but not in ADM. Long-duration ppES with an inter-pulse interval of 5 ms significantly decreased SAI but not MEPs in APB. In contrast, long-duration ppES did not affect ADM. Conclusion: The afferent inputs induced by ppES-5 ms were effective for transiently increasing MEP and sustaining SAI reduction. PMID:26733847

  11. Combined effect of motor imagery and peripheral nerve electrical stimulation on the motor cortex.

    PubMed

    Saito, Kei; Yamaguchi, Tomofumi; Yoshida, Naoshin; Tanabe, Shigeo; Kondo, Kunitsugu; Sugawara, Kenichi

    2013-06-01

    Although motor imagery enhances the excitability of the corticospinal tract, there are no peripheral afferent inputs during motor imagery. In contrast, peripheral nerve electrical stimulation (ES) can induce peripheral afferent inputs; thus, a combination of motor imagery and ES may enhance the excitability of the corticospinal tract compared with motor imagery alone. Moreover, the level of stimulation intensity may also be related to the modulation of the excitability of the corticospinal tract during motor imagery. Here, we evaluated whether a combination of motor imagery and peripheral nerve ES influences the excitability of the corticospinal tract and measured the effect of ES intensity on the excitability induced during motor imagery. The imagined task was a movement that involved touching the thumb to the little finger, whereas ES involved simultaneous stimulation of the ulnar and median nerves at the wrist. Two different ES intensities were used, one above the motor threshold and another above the sensory threshold. Further, we evaluated whether actual movement with afferent input induced by ES modulates the excitability of the corticospinal tract as well as motor imagery. We found that a combination of motor imagery and ES enhanced the excitability of the motor cortex in the thenar muscle compared with the other condition. Furthermore, we established that the modulation of the corticospinal tract was related to ES intensity. However, we found that the excitability of the corticospinal tract induced by actual movement was enhanced by peripheral nerve ES above the sensory threshold.

  12. Electrical stimulation of upper airway musculature.

    PubMed

    Smith, P L; Eisele, D W; Podszus, T; Penzel, T; Grote, L; Peter, J H; Schwartz, A R

    1996-12-01

    Investigators have postulated that pharyngeal collapse during sleep in patients with obstructive sleep apnea (OSA) may be alleviated by stimulating the genioglossus. The effect of electrical stimulation (ES) of the genioglossus on pharyngeal patency was examined in an isolated feline upper airway preparation and in apneic humans during sleep. We found that stimulation of the genioglossus (n = 8) and of the hypoglossal nerve (n = 1) increased maximum airflow through the isolated feline upper airway in humans during sleep. Additional findings in the isolated feline upper airway suggest that such increases in airflow were due to decreases in pharyngeal collapsibility. The evidence suggests that improvements in airflow dynamics with electrical stimulation are due to selective recruitment of the genioglossus, rather than due to nonspecific activation of the pharyngeal musculature or arousal from sleep. The implications of these results for future therapy with ES are discussed.

  13. Effects of stimulation of group I afferents from flexor muscles on heterosynaptic facilitation of monosynaptic reflexes produced by Ia and descending inputs: a test for presynaptic inhibition.

    PubMed

    Rudomin, P; Jiménez, I; Enriquez, M

    1991-01-01

    1. In the chloralose anesthetized cat, conditioning stimulation of group I flexor afferents depresses the monosynaptic potentials generated by Ia afferents in single spinal motoneurons or in populations of motoneurons without affecting the monosynaptic potentials produced by stimulation of descending fibers in the ipsilateral ventromedial fasciculus (VMF). 2. Heterosynaptic facilitation of monosynaptic reflexes was used to test changes in the presynaptic effectiveness of excitatory inputs with direct connections with motoneurons. We found that the heterosynaptic facilitation of Ia origin was reduced by conditioning stimulation of group I afferents from flexors, without affecting the heterosynaptic facilitation produced by stimulation of the VMF. 3. These results confirm and expand previous observations showing that the synaptic effectiveness of descending fibers synapsing with motoneurons is not subjected to a presynaptic control mechanism of the type acting on Ia fiber terminals, and provide further basis for the use of changes in heterosynaptic facilitation of monosynaptic reflexes of Ia origin as an estimate of changes in presynaptic inhibition of Ia fibers (Hultborn et al. 1987a).

  14. Macrophage-Colony Stimulating Factor Derived from Injured Primary Afferent Induces Proliferation of Spinal Microglia and Neuropathic Pain in Rats

    PubMed Central

    Okubo, Masamichi; Yamanaka, Hiroki; Kobayashi, Kimiko; Dai, Yi; Kanda, Hirosato; Yagi, Hideshi; Noguchi, Koichi

    2016-01-01

    Peripheral nerve injury induces proliferation of microglia in the spinal cord, which can contribute to neuropathic pain conditions. However, candidate molecules for proliferation of spinal microglia after injury in rats remain unclear. We focused on the colony-stimulating factors (CSFs) and interleukin-34 (IL-34) that are involved in the proliferation of the mononuclear phagocyte lineage. We examined the expression of mRNAs for macrophage-CSF (M-CSF), granulocyte macrophage-CSF (GM-CSF), granulocyte-CSF (G-CSF) and IL-34 in the dorsal root ganglion (DRG) and spinal cord after spared nerve injury (SNI) in rats. RT-PCR and in situ hybridization revealed that M-CSF and IL-34, but not GM- or G-CSF, mRNAs were constitutively expressed in the DRG, and M-CSF robustly increased in injured-DRG neurons. M-CSF receptor mRNA was expressed in naive rats and increased in spinal microglia following SNI. Intrathecal injection of M-CSF receptor inhibitor partially but significantly reversed the proliferation of spinal microglia and in early phase of neuropathic pain induced by SNI. Furthermore, intrathecal injection of recombinant M-CSF induced microglial proliferation and mechanical allodynia. Here, we demonstrate that M-CSF is a candidate molecule derived from primary afferents that induces proliferation of microglia in the spinal cord and leads to induction of neuropathic pain after peripheral nerve injury in rats. PMID:27071004

  15. 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…

  16. Electrical Stimulation as an Aid to Speechreading.

    ERIC Educational Resources Information Center

    Tyler, Richard S.; And Others

    1988-01-01

    This paper, discussing use of electrical stimulation by postlingually deafened adults to supplement speechreading, focuses on: information conveyed by vision, acoustic information needed to resolve visual confusions, basic psychophysical abilities of cochlear implant patients, auditory-alone and audiovisual perception by cochlear-implant patients,…

  17. Excitatory actions of GABA in developing chick vestibular afferents: effects on resting electrical activity.

    PubMed

    Cortes, Celso; Galindo, Fabian; Galicia, Salvador; Cebada, Jorge; Flores, Amira

    2013-07-01

    The aim of this study was to characterize the effect of γ-aminobutyric acid (GABA) in the resting multiunit activity of the vestibular afferents during development using the isolated inner ear of embryonic and postnatal chickens (E15-E21 and P5). GABA (10(-3) to 10(-5) M; n = 133) and muscimol (10(-3) M) elicited an increase in the frequency of the basal discharge of the vestibular afferents. We found that GABA action was dose-dependent and inversely related to animal age. Thus, the largest effect was observed in embryonic ages such as E15 and E17 and decreases in E21 and P5. The GABAA receptor antagonists, bicuculline (10(-5) M; n = 10) and picrotoxin (10(-4) M; n = 10), significantly decreased the excitatory action of GABA and muscimol (10(-3) M). Additionally, CNQX 10(-6) M, MCPG 10(-5) M and 7ClKyn 10(-5) M (n = 5) were co-applied by bath substitution (n = 5). Both the basal discharge and the GABA action significantly decreased in these experimental conditions. The chloride channel blocker 9-AC 0.5 mM produced an important reduction in the effect of GABA 10(-3) (n = 5) and 10(-4) M (n = 5). Thus, our results suggest an excitatory role of GABA in the resting activity of the vestibular afferents that can be explained by changes in the gradient of concentration of Cl(-) during development. We show for the first time that the magnitude of this GABA effect decreases at later stages of embryonic and early postnatal development. Taking into account the results with glutamatergic antagonists, we conclude that GABA has a presynaptic action but is not the neurotransmitter in the vestibular afferent synapses, although it could act as a facilitator of the spontaneous activity and may regulate glutamate release.

  18. 21 CFR 882.1870 - Evoked response electrical stimulator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Evoked response electrical stimulator. 882.1870... electrical stimulator. (a) Identification. An evoked response electrical stimulator is a device used to apply an electrical stimulus to a patient by means of skin electrodes for the purpose of measuring...

  19. 21 CFR 882.1870 - Evoked response electrical stimulator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Evoked response electrical stimulator. 882.1870... electrical stimulator. (a) Identification. An evoked response electrical stimulator is a device used to apply an electrical stimulus to a patient by means of skin electrodes for the purpose of measuring...

  20. 21 CFR 882.1870 - Evoked response electrical stimulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Evoked response electrical stimulator. 882.1870... electrical stimulator. (a) Identification. An evoked response electrical stimulator is a device used to apply an electrical stimulus to a patient by means of skin electrodes for the purpose of measuring...

  1. 21 CFR 882.1870 - Evoked response electrical stimulator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Evoked response electrical stimulator. 882.1870... electrical stimulator. (a) Identification. An evoked response electrical stimulator is a device used to apply an electrical stimulus to a patient by means of skin electrodes for the purpose of measuring...

  2. Brain responses to cardiac electrical stimulation: a new EEG method for evaluating cardiac sensation.

    PubMed

    Suzuki, Hideaki; Hirose, Masanori; Watanabe, Satoshi; Fukuda, Koji; Fukudo, Shin; Shimokawa, Hiroaki

    2012-01-01

    Although cardiac sensation, such as palpitation or chest pain, is common and is sometimes a malignant sign of heart diseases, the mechanism by which the human brain responds to afferent signals from the heart remains unclear. In this study, we investigated whether electrical stimulation of the heart provokes brain responses in humans. We examined 15 patients (age: 65.4 ± 3.1 years old, 11 males and 4 females) implanted with either a cardiac pacemaker or cardiac resynchronization therapy (CRT) device. Electroencephalogram (EEG) was simultaneously recorded from the vertex during right ventricular pacing at 70-100 beats/min at baseline (1.5 V) and intense (6-8 V) stimulation sessions. We evaluated brain responses to cardiac electrical stimulation by measuring cerebral potentials that were obtained by subtracting the average of 100 EEG waves triggered by cardiac pacing during baseline stimulation from those during the intense stimulation. Intense stimulation of the cardiac pacemaker or CRT device reproducibly induced cardiac sensation in 6 out of the 15 patients; namely, the remaining 9 patients showed no reproducible response. Brain responses were evident by averaging cerebral potentials from all of the 15 patients and those from 6 patients with reproducible cardiac sensation. To the best our knowledge, this is the first report that demonstrates the brain responses to cardiac electrical stimulation in humans. This new method should be useful for examining pathophysiology of cardiac diseases with pathological cardiac sensation, including cardiac anxiety and silent myocardial ischemia.

  3. Mechanisms of electrical stimulation with neural prostheses.

    PubMed

    Rattay, F; Resatz, S; Lutter, P; Minassian, K; Jilge, B; Dimitrijevic, M R

    2003-01-01

    Individual electric and geometric characteristics of neural substructures can have surprising effects on artificially controlled neural signaling. A rule of thumb approved for the stimulation of long peripheral axons may not hold when the central nervous system is involved. This is demonstrated here with a comparison of results from the electrically stimulated cochlea, retina, and spinal cord. A generalized form of the activating function together with accurate modeling of the neural membrane dynamics are the tools to analyze the excitation mechanisms initiated by neural prostheses. Analysis is sometimes possible with a linear theory, in other cases, simulation of internal calcium concentration or ion channel current fluctuations is needed to see irregularities in spike trains. Spike initiation site can easily change within a single target neuron under constant stimulation conditions of a cochlear implant. Poor myelinization in the soma region of the human cochlear neurons causes firing characteristics different from any animal data. Retinal ganglion cells also generate propagating spikes within the dendritic tree. Bipolar cells in the retina are expected to respond with neurotransmitter release before a spike is generated in the ganglion cell, even when they are far away from the electrode. Epidural stimulation of the lumbar spinal cord predominantly stimulates large sensory axons in the dorsal roots which induce muscle reflex responses. Analysis with the generalized activating function, computer simulations of the nonlinear neural membrane behavior together with experimental and clinical data analysis enlighten our understanding of artificial firing patterns influenced by neural prostheses.

  4. Innervation of enteric mast cells by primary spinal afferents in guinea pig and human small intestine.

    PubMed

    Wang, Guo-Du; Wang, Xi-Yu; Liu, Sumei; Qu, Meihua; Xia, Yun; Needleman, Bradley J; Mikami, Dean J; Wood, Jackie D

    2014-10-01

    Mast cells express the substance P (SP) neurokinin 1 receptor and the calcitonin gene-related peptide (CGRP) receptor in guinea pig and human small intestine. Enzyme-linked immunoassay showed that activation of intramural afferents by antidromic electrical stimulation or by capsaicin released SP and CGRP from human and guinea pig intestinal segments. Electrical stimulation of the afferents evoked slow excitatory postsynaptic potentials (EPSPs) in the enteric nervous system. The slow EPSPs were mediated by tachykinin neurokinin 1 and CGRP receptors. Capsaicin evoked slow EPSP-like responses that were suppressed by antagonists for protease-activated receptor 2. Afferent stimulation evoked slow EPSP-like excitation that was suppressed by mast cell-stabilizing drugs. Histamine and mast cell protease II were released by 1) exposure to SP or CGRP, 2) capsaicin, 3) compound 48/80, 4) elevation of mast cell Ca²⁺ by ionophore A23187, and 5) antidromic electrical stimulation of afferents. The mast cell stabilizers cromolyn and doxantrazole suppressed release of protease II and histamine when evoked by SP, CGRP, capsaicin, A23187, electrical stimulation of afferents, or compound 48/80. Neural blockade by tetrodotoxin prevented mast cell protease II release in response to antidromic electrical stimulation of mesenteric afferents. The results support a hypothesis that afferent innervation of enteric mast cells releases histamine and mast cell protease II, both of which are known to act in a diffuse paracrine manner to influence the behavior of enteric nervous system neurons and to elevate the sensitivity of spinal afferent terminals.

  5. Innervation of enteric mast cells by primary spinal afferents in guinea pig and human small intestine

    PubMed Central

    Wang, Guo-Du; Wang, Xi-Yu; Liu, Sumei; Qu, Meihua; Xia, Yun; Needleman, Bradley J.; Mikami, Dean J.

    2014-01-01

    Mast cells express the substance P (SP) neurokinin 1 receptor and the calcitonin gene-related peptide (CGRP) receptor in guinea pig and human small intestine. Enzyme-linked immunoassay showed that activation of intramural afferents by antidromic electrical stimulation or by capsaicin released SP and CGRP from human and guinea pig intestinal segments. Electrical stimulation of the afferents evoked slow excitatory postsynaptic potentials (EPSPs) in the enteric nervous system. The slow EPSPs were mediated by tachykinin neurokinin 1 and CGRP receptors. Capsaicin evoked slow EPSP-like responses that were suppressed by antagonists for protease-activated receptor 2. Afferent stimulation evoked slow EPSP-like excitation that was suppressed by mast cell-stabilizing drugs. Histamine and mast cell protease II were released by 1) exposure to SP or CGRP, 2) capsaicin, 3) compound 48/80, 4) elevation of mast cell Ca2+ by ionophore A23187, and 5) antidromic electrical stimulation of afferents. The mast cell stabilizers cromolyn and doxantrazole suppressed release of protease II and histamine when evoked by SP, CGRP, capsaicin, A23187, electrical stimulation of afferents, or compound 48/80. Neural blockade by tetrodotoxin prevented mast cell protease II release in response to antidromic electrical stimulation of mesenteric afferents. The results support a hypothesis that afferent innervation of enteric mast cells releases histamine and mast cell protease II, both of which are known to act in a diffuse paracrine manner to influence the behavior of enteric nervous system neurons and to elevate the sensitivity of spinal afferent terminals. PMID:25147231

  6. Tissue damage thresholds during therapeutic electrical stimulation

    NASA Astrophysics Data System (ADS)

    Cogan, Stuart F.; Ludwig, Kip A.; Welle, Cristin G.; Takmakov, Pavel

    2016-04-01

    Objective. Recent initiatives in bioelectronic modulation of the nervous system by the NIH (SPARC), DARPA (ElectRx, SUBNETS) and the GlaxoSmithKline Bioelectronic Medicines effort are ushering in a new era of therapeutic electrical stimulation. These novel therapies are prompting a re-evaluation of established electrical thresholds for stimulation-induced tissue damage. Approach. In this review, we explore what is known and unknown in published literature regarding tissue damage from electrical stimulation. Main results. For macroelectrodes, the potential for tissue damage is often assessed by comparing the intensity of stimulation, characterized by the charge density and charge per phase of a stimulus pulse, with a damage threshold identified through histological evidence from in vivo experiments as described by the Shannon equation. While the Shannon equation has proved useful in assessing the likely occurrence of tissue damage, the analysis is limited by the experimental parameters of the original studies. Tissue damage is influenced by factors not explicitly incorporated into the Shannon equation, including pulse frequency, duty cycle, current density, and electrode size. Microelectrodes in particular do not follow the charge per phase and charge density co-dependence reflected in the Shannon equation. The relevance of these factors to tissue damage is framed in the context of available reports from modeling and in vivo studies. Significance. It is apparent that emerging applications, especially with microelectrodes, will require clinical charge densities that exceed traditional damage thresholds. Experimental data show that stimulation at higher charge densities can be achieved without causing tissue damage, suggesting that safety parameters for microelectrodes might be distinct from those defined for macroelectrodes. However, these increased charge densities may need to be justified by bench, non-clinical or clinical testing to provide evidence of device

  7. Tissue damage thresholds during therapeutic electrical stimulation

    PubMed Central

    Cogan, Stuart F; Ludwig, Kip A; Welle, Cristin G; Takmakov, Pavel

    2017-01-01

    Objective Recent initiatives in bioelectronic modulation of the nervous system by the NIH (SPARC), DARPA (ElectRx, SUBNETS) and the GlaxoSmithKline Bioelectronic Medicines effort are ushering in a new era of therapeutic electrical stimulation. These novel therapies are prompting a re-evaluation of established electrical thresholds for stimulation-induced tissue damage. Approach In this review, we explore what is known and unknown in published literature regarding tissue damage from electrical stimulation. Main results For macroelectrodes, the potential for tissue damage is often assessed by comparing the intensity of stimulation, characterized by the charge density and charge per phase of a stimulus pulse, with a damage threshold identified through histological evidence from in vivo experiments as described by the Shannon equation. While the Shannon equation has proved useful in assessing the likely occurrence of tissue damage, the analysis is limited by the experimental parameters of the original studies. Tissue damage is influenced by factors not explicitly incorporated into the Shannon equation, including pulse frequency, duty cycle, current density, and electrode size. Microelectrodes in particular do not follow the charge per phase and charge density co-dependence reflected in the Shannon equation. The relevance of these factors to tissue damage is framed in the context of available reports from modeling and in vivo studies. Significance It is apparent that emerging applications, especially with microelectrodes, will require clinical charge densities that exceed traditional damage thresholds. Experimental data show that stimulation at higher charge densities can be achieved without causing tissue damage, suggesting that safety parameters for microelectrodes might be distinct from those defined for macroelectrodes. However, these increased charge densities may need to be justified by bench, non-clinical or clinical testing to provide evidence of device safety

  8. The electromyographic silent period produced by supramaximal electrical stimulation in normal man

    PubMed Central

    McLellan, D. L.

    1973-01-01

    The electromyographic silent period produced by supramaximal electrical stimulation of the median nerve was recorded in the abductor pollicis brevis muscle of four normal subjects during maximal isometric voluntary contraction. Except for an inconstant F response, electrical silence could usually be induced in the muscle from the twitch potential until the reappearance of uninterrupted voluntary activity. The silent period produced by stimulation at the wrist was approximately 25 msec longer than that produced by stimulation at the elbow and was independent of muscle tension. Further shortening of the muscle during the twitch contraction did not significantly alter the length of the silent period. A silent period in the abductor pollicis brevis muscle was also obtained after stimulation of the ulnar nerve, at the wrist and at the elbow. The onset of this period of silence was delayed, but it ended at the same time after the stimulus as the corresponding silent periods produced by median nerve stimulation. It is concluded that the end point of the silent period produced by supramaximal electrical stimulation of a mixed peripheral nerve is determined by an inhibitory spinal reflex, afferent impulses travelling in slowly-conducting fibres that are directly activated by the stimulus. Under these conditions the length of the silent period gives no indication of spindle activity in the muscle. Images PMID:4268362

  9. Electrical stimulation systems for cardiac tissue engineering.

    PubMed

    Tandon, Nina; Cannizzaro, Christopher; Chao, Pen-Hsiu Grace; Maidhof, Robert; Marsano, Anna; Au, Hoi Ting Heidi; Radisic, Milica; Vunjak-Novakovic, Gordana

    2009-01-01

    We describe a protocol for tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cells with the application of pulsatile electrical fields designed to mimic those present in the native heart. Tissue culture is conducted in a customized chamber built to allow for cultivation of (i) engineered three-dimensional (3D) cardiac tissue constructs, (ii) cell monolayers on flat substrates or (iii) cells on patterned substrates. This also allows for analysis of the individual and interactive effects of pulsatile electrical field stimulation and substrate topography on cell differentiation and assembly. The protocol is designed to allow for delivery of predictable electrical field stimuli to cells, monitoring environmental parameters, and assessment of cell and tissue responses. The duration of the protocol is 5 d for two-dimensional cultures and 10 d for 3D cultures.

  10. Electrical stimulation systems for cardiac tissue engineering

    PubMed Central

    Tandon, Nina; Cannizzaro, Christopher; Chao, Pen-Hsiu Grace; Maidhof, Robert; Marsano, Anna; Au, Hoi Ting Heidi; Radisic, Milica; Vunjak-Novakovic, Gordana

    2009-01-01

    We describe a protocol for tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cells with the application of pulsatile electrical fields designed to mimic those present in the native heart. Tissue culture is conducted in a customized chamber built to allow for cultivation of (i) engineered three-dimensional (3D) cardiac tissue constructs, (ii) cell monolayers on flat substrates or (iii) cells on patterned substrates. This also allows for analysis of the individual and interactive effects of pulsatile electrical field stimulation and substrate topography on cell differentiation and assembly. The protocol is designed to allow for delivery of predictable electrical field stimuli to cells, monitoring environmental parameters, and assessment of cell and tissue responses. The duration of the protocol is 5 d for two-dimensional cultures and 10 d for 3D cultures. PMID:19180087

  11. Functional Electrical Stimulation in Children and Adolescents with Cerebral Palsy

    ERIC Educational Resources Information Center

    van der Linden, Marietta

    2012-01-01

    In this article, the author talks about functional electrical stimulation in children and adolescents with cerebral palsy. Functional electrical stimulation (FES) is defined as the electrical stimulation of muscles that have impaired motor control, in order to produce a contraction to obtain functionally useful movement. It was first proposed in…

  12. A microprocessor-based multichannel subsensory stochastic resonance electrical stimulator.

    PubMed

    Chang, Gwo-Ching

    2013-01-01

    Stochastic resonance electrical stimulation is a novel intervention which provides potential benefits for improving postural control ability in the elderly, those with diabetic neuropathy, and stroke patients. In this paper, a microprocessor-based subsensory white noise electrical stimulator for the applications of stochastic resonance stimulation is developed. The proposed stimulator provides four independent programmable stimulation channels with constant-current output, possesses linear voltage-to-current relationship, and has two types of stimulation modes, pulse amplitude and width modulation.

  13. Neurones in the brain stem of the cat excited by vagal afferent fibres from the heart and lungs.

    PubMed Central

    Bennett, J A; Goodchild, C S; Kidd, C; McWilliam, P N

    1985-01-01

    Extracellular recordings were made from 164 neurones in the nucleus tractus solitarius and dorsal motor vagal nucleus of the chloralose-anaesthetized cat. 139 neurones were excited synaptically and 25 non-synaptically by electrical stimulation of cardiac and pulmonary vagal branches. Synaptically excited neurones fall into two populations, one activated solely by myelinated afferent fibres and a second activated solely by non-myelinated afferent fibres. 94 neurones were synaptically excited by afferent fibres in a single vagal branch while 45 were excited by stimulation of two or three branches. Neurones responding to volleys in myelinated afferent fibres were located in both medial and lateral regions of the nucleus tractus solitarius whilst those excited by non-myelinated afferent fibres were restricted to the medial region. Consistent differences in the locations of neurones excited by stimulation of either cardiac or pulmonary or by single or several branches could not be distinguished. PMID:4093876

  14. Deep Brain Electrical Stimulation in Epilepsy

    NASA Astrophysics Data System (ADS)

    Rocha, Luisa L.

    2008-11-01

    The deep brain electrical stimulation has been used for the treatment of neurological disorders such as Parkinson's disease, chronic pain, depression and epilepsy. Studies carried out in human brain indicate that the application of high frequency electrical stimulation (HFS) at 130 Hz in limbic structures of patients with intractable temporal lobe epilepsy abolished clinical seizures and significantly decreased the number of interictal spikes at focus. The anticonvulsant effects of HFS seem to be more effective in patients with less severe epilepsy, an effect associated with a high GABA tissue content and a low rate of cell loss. In addition, experiments using models of epilepsy indicate that HFS (pulses of 60 μs width at 130 Hz at subthreshold current intensity) of specific brain areas avoids the acquisition of generalized seizures and enhances the postictal seizure suppression. HFS is also able to modify the status epilepticus. It is concluded that the effects of HFS may be a good strategy to reduce or avoid the epileptic activity.

  15. A Systematic Review of Electric-Acoustic Stimulation

    PubMed Central

    Ching, Teresa Y. C.; Cowan, Robert

    2013-01-01

    Cochlear implant systems that combine electric and acoustic stimulation in the same ear are now commercially available and the number of patients using these devices is steadily increasing. In particular, electric-acoustic stimulation is an option for patients with severe, high frequency sensorineural hearing impairment. There have been a range of approaches to combining electric stimulation and acoustic hearing in the same ear. To develop a better understanding of fitting practices for devices that combine electric and acoustic stimulation, we conducted a systematic review addressing three clinical questions: what is the range of acoustic hearing in the implanted ear that can be effectively preserved for an electric-acoustic fitting?; what benefits are provided by combining acoustic stimulation with electric stimulation?; and what clinical fitting practices have been developed for devices that combine electric and acoustic stimulation? A search of the literature was conducted and 27 articles that met the strict evaluation criteria adopted for the review were identified for detailed analysis. The range of auditory thresholds in the implanted ear that can be successfully used for an electric-acoustic application is quite broad. The effectiveness of combined electric and acoustic stimulation as compared with electric stimulation alone was consistently demonstrated, highlighting the potential value of preservation and utilization of low frequency hearing in the implanted ear. However, clinical procedures for best fitting of electric-acoustic devices were varied. This clearly identified a need for further investigation of fitting procedures aimed at maximizing outcomes for recipients of electric-acoustic devices. PMID:23539259

  16. A continuum model of retinal electrical stimulation

    NASA Astrophysics Data System (ADS)

    Joarder, Saiful A.; Abramian, Miganoosh; Suaning, Gregg J.; Lovell, Nigel H.; Dokos, Socrates

    2011-10-01

    A continuum mathematical model of retinal electrical stimulation is described. The model is represented by a passive vitreous domain, a thin layer of active retinal ganglion cell (RGC) tissue adjacent to deeper passive neural layers of the retina, the retinal pigmented epithelium (RPE) and choroid thus ending at the sclera. To validate the model, in vitro epiretinal responses to stimuli from 50 µm disk electrodes, arranged in a hexagonal mosaic, were recorded from rabbit retinas. 100 µs/phase anodic-first biphasic current pulses were delivered to the retinal surface in both the mathematical model and experiments. RGC responses were simulated and recorded using extracellular microelectrodes. The model's epiretinal thresholds compared favorably with the in vitro data. In addition, simulations showed that single-return bipolar electrodes recruited a larger area of the retina than twin-return or six-return electrodes arranged in a hexagonal layout in which a central stimulating electrode is surrounded by six, eqi-spaced returns. Simulations were also undertaken to investigate the patterns of RGC activation in an anatomically-accurate model of the retina, as well as RGC activation patterns for subretinal and suprachoroidal bipolar stimulation. This paper was originally submitted for the special issue containing contributions from the Sixth Biennial Research Congress of The Eye and the Chip.

  17. [Magneto-electrical stimulation (MES)--compared with percutaneous electrical stimulation (PES)].

    PubMed

    Ugawa, Y; Kohara, N; Shimpo, T; Mannen, T

    1989-01-01

    The central motor conduction was studied in 30 normal volunteers using a recently developed magneto-electrical stimulation technique (MES). The results were compared with those obtained by percutaneous electrical stimulation technique (PES) described previously. We made a magnetic stimulator similar to that of Barker et al. To stimulate the motor cortex, the magnetic coil was placed over the head. It was placed over the seventh cervical spinous process (C7) for cervical stimulation, and the first lumbar spinous process (L1) for lumbar stimulation. Cortical stimulation was performed when the subjects were at rest, and also at during weak voluntary contraction in some of them. Recordings were made from the deltoid (Del), biceps brachii (Bi), extensor carpi radialis (ECR), thenar, quadriceps femoris (Quad), tibialis anterior (TA) and flexor hallucis brevis (FHB) muscles with a pair of surface electrodes. The cortical and spinal latent periods (Lcor and Lsp, respectively) were measured. The central conduction time (CCT) was obtained by subtracting Lsp from Lcor for each muscle. In all subjects, responses were readily obtained by cortical, cervical and lumbar stimulations without discomfort in all the muscles examined. The cortical responses with amplitudes of more than 1mV could be recorded even in the lower limb muscles. There were no significant differences in Lsp and CCT between MES and PES, in all the upper limb muscles examined. The Lcors of the lower limb muscles obtained by MES were not different from those obtained by PES. However, the Lsps obtained by MES were significantly shorter than those by PES in the Quad and TA muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Presence and Absence of Muscle Contraction Elicited by Peripheral Nerve Electrical Stimulation Differentially Modulate Primary Motor Cortex Excitability

    PubMed Central

    Sasaki, Ryoki; Kotan, Shinichi; Nakagawa, Masaki; Miyaguchi, Shota; Kojima, Sho; Saito, Kei; Inukai, Yasuto; Onishi, Hideaki

    2017-01-01

    Modulation of cortical excitability by sensory inputs is a critical component of sensorimotor integration. Sensory afferents, including muscle and joint afferents, to somatosensory cortex (S1) modulate primary motor cortex (M1) excitability, but the effects of muscle and joint afferents specifically activated by muscle contraction are unknown. We compared motor evoked potentials (MEPs) following median nerve stimulation (MNS) above and below the contraction threshold based on the persistence of M-waves. Peripheral nerve electrical stimulation (PES) conditions, including right MNS at the wrist at 110% motor threshold (MT; 110% MNS condition), right MNS at the index finger (sensory digit nerve stimulation [DNS]) with stimulus intensity approximately 110% MNS (DNS condition), and right MNS at the wrist at 90% MT (90% MNS condition) were applied. PES was administered in a 4 s ON and 6 s OFF cycle for 20 min at 30 Hz. In Experiment 1 (n = 15), MEPs were recorded from the right abductor pollicis brevis (APB) before (baseline) and after PES. In Experiment 2 (n = 15), M- and F-waves were recorded from the right APB. Stimulation at 110% MNS at the wrist evoking muscle contraction increased MEP amplitudes after PES compared with those at baseline, whereas DNS at the index finger and 90% MNS at the wrist not evoking muscle contraction decreased MEP amplitudes after PES. M- and F-waves, which reflect spinal cord or muscular and neuromuscular junctions, did not change following PES. These results suggest that muscle contraction and concomitant muscle/joint afferent inputs specifically enhance M1 excitability. PMID:28392766

  19. Functional Electrical Stimulation and Spinal Cord Injury

    PubMed Central

    Ho, Chester H.; Triolo, Ronald J.; Elias, Anastasia L.; Kilgore, Kevin L.; DiMarco, Anthony F.; Bogie, Kath; Vette, Albert H.; Audu, Musa; Kobetic, Rudi; Chang, Sarah R.; Chan, K. Ming; Dukelow, Sean; Bourbeau, Dennis J.; Brose, Steven W.; Gustafson, Kenneth J.; Kiss, Zelma; Mushahwar, Vivian K.

    2015-01-01

    Synopsis Spinal cord injuries (SCI) can disrupt communications between the brain and the body, leading to a loss of control over otherwise intact neuromuscular systems. The use of electrical stimulation (ES) of the central and peripheral nervous system can take advantage of these intact neuromuscular systems to provide therapeutic exercise options, to allow functional restoration, and even to manage or prevent many medical complications following SCI. The use of ES for the restoration of upper extremity, lower extremity and truncal functions can make many activities of daily living a potential reality for individuals with SCI. Restoring bladder and respiratory functions and preventing pressure ulcers may significantly decrease the morbidity and mortality following SCI. Many of the ES devices are already commercially available and should be considered by all SCI clinicians routinely as part of the lifelong rehabilitation care plan for all eligible individuals with SCI. PMID:25064792

  20. Selective cortical control of information flow through different intraspinal collaterals of the same muscle afferent fiber.

    PubMed

    Eguibar, J R; Quevedo, J; Jiménez, I; Rudomin, P

    1994-04-18

    We have analyzed in the anesthetized cat the effects of electrical stimulation of the cerebral cortex on the intraspinal threshold of two collaterals belonging to the same muscle spindle or tendon organ afferent fiber. The results obtained provide, for the first time, direct evidence showing that the motor cortex is able to modify, in a highly selective manner, the synaptic effectiveness of individual collaterals of the same primary afferent fiber. This presynaptic control could function as a mechanism that allows funneling of information to specific groups of spinal neurons in the presence of extensive intraspinal branching of the afferent fibers.

  1. Surface electrical stimulation to evoke referred sensation.

    PubMed

    Forst, Johanna C; Blok, Derek C; Slopsema, Julia P; Boss, John M; Heyboer, Lane A; Tobias, Carson M; Polasek, Katharine H

    2015-01-01

    Surface electrical stimulation (SES) is being investigated as a noninvasive method to evoke natural sensations distal to electrode location. This may improve treatment for phantom limb pain as well as provide an alternative method to deliver sensory feedback. The median and/or ulnar nerves of 35 subjects were stimulated at the elbow using surface electrodes. Strength-duration curves of hand sensation were found for each subject. All subjects experienced sensation in their hand, which was mostly described as a paresthesia-like sensation. The rheobase and chronaxie values were found to be lower for the median nerve than the ulnar nerve, with no significant difference between sexes. Repeated sessions with the same subject resulted in sufficient variability to suggest that recalculating the strength-duration curve for each electrode placement is necessary. Most of the recruitment curves in this study were generated with 28 to 36 data points. To quickly reproduce these curves with limited increase in error, we recommend 10 data points. Future studies will focus on obtaining different sensations using SES with the strength-duration curve defining the threshold of the effective parameter space.

  2. Colon emptying induced by sequential electrical stimulation in rats.

    PubMed

    Sevcencu, Cristian; Rijkhoff, Nico J M; Sinkjaer, Thomas

    2005-12-01

    Electrical stimulation could be used to induce colon emptying. The present experiments were performed to establish a stimulation pattern to optimize the stimulation parameters and to test neural involvement in propulsion induced by electrical stimulation. Colon segments were sequentially stimulated using rectangular pulses. The resulting propulsive activity displaced intraluminal content in consecutive propulsion steps. The propulsion steps differed in displacement latency, distance, and velocity along the stimulated colon. Increasing the pulse duration or amplitude resulted in a decrease of the latency. Increasing the stimulation amplitude doubled the displacement distance. The frequencies tested in the present study did not affect propulsion. Inhibition of cholinergic and nitrergic pathways inhibited propulsion. Electrical stimulation can induce colonic propulsion. Motor differences are present along the descending colon. The most suitable combination of pulse parameters regarding colon stimulation is 0.3 ms, 5 mA, 10 Hz. Neural circuits are involved in propulsion when using these values.

  3. Activation of SC during electrical stimulation of LGN: retinal antidromic stimulation or corticocollicular activation?

    PubMed

    Murayama, Yusuke; Augath, Mark; Logothetis, Nikos K

    2011-12-01

    We have recently used combined electrostimulation, neurophysiology, microinjection and functional magnetic resonance imaging (fMRI) to study the cortical activity patterns elicited during stimulation of cortical afferents in monkeys. We found that stimulation of a site in lateral geniculate nucleus (LGN) increases the fMRI signal in the regions of primary visual cortex receiving input from that site, but suppresses it in the retinotopically matched regions of extrastriate cortex. Intracortical injection experiments showed that such suppression is due to synaptic inhibition. During these experiments, we have consistently observed activation of superior colliculus (SC) following LGN stimulation. Since LGN does not directly project to SC, the current study investigated the origin of SC activation. By examining experimental manipulations inactivating the primary visual cortex, we present here evidence that the robust SC activation, which follows the stimulation of LGN, is due to the activation of corticocollicular pathway.

  4. Angiotensin II-stimulated Ca2+ entry mechanisms in afferent arterioles: role of transient receptor potential canonical channels and reverse Na+/Ca2+ exchange.

    PubMed

    Fellner, Susan K; Arendshorst, William J

    2008-01-01

    In afferent arterioles, the signaling events that lead to an increase in cytosolic Ca(2+) concentration ([Ca(2+)](i)) and initiation of vascular contraction are increasingly being delineated. We have recently studied angiotensin II (ANG II)-mediated effects on sarcoplasmic reticulum (SR) mobilization of Ca(2+) and the role of superoxide and cyclic adenosine diphosphoribose in these processes. In the current study we investigated the participation of transient receptor potential canonical channels (TRPC) and a Na(+)/Ca(2+) exchanger (NCX) in Ca(2+) entry mechanisms. Afferent arterioles, isolated with the magnetized polystyrene bead method, were loaded with fura-2 to measure [Ca(2+)](i) ratiometrically. We observed that the Ca(2+)-dependent chloride channel blocker niflumic acid (10 and 50 microM) affects neither the peak nor plateau [Ca(2+)](i) response to ANG II. Arterioles were pretreated with ryanodine (100 microM) and TMB-8 to block SR mobilization via the ryanodine receptor and inositol trisphosphate receptor, respectively. The peak [Ca(2+)](i) response to ANG II was reduced by 40%. Addition of 2-aminoethoxydiphenyl borane to block TRPC-mediated Ca(2+) entry inhibited the peak [Ca(2+)](i) ANG II response by 80% and the plateau by 74%. Flufenamic acid (FFA; 50 microM), which stimulates TRPC6, caused a sustained increase of [Ca(2+)](i) of 146 nM. This response was unaffected by diltiazem or nifedipine. KB-R7943 (at the low concentration of 10 microM) inhibits reverse (but not forward) mode NCX. KB-R7943 decreased the peak [Ca(2+)](i) response to ANG II by 48% and to FFA by 38%. We conclude that TRPC6 and reverse-mode NCX may be important Ca(2+) entry pathways in afferent arterioles.

  5. Knee Osteoarthritis: Does Transcutaneous Electrical Nerve Stimulation Work?

    PubMed

    Cherian, Jeffrey J; Kapadia, Bhaveen H; McElroy, Mark J; Johnson, Aaron J; Bhave, Anil; Harwin, Steven F; Mont, Michael A

    2016-01-01

    Transcutaneous electrical nerve stimulation has been proposed as a nonoperative treatment for osteoarthritis. The purpose of this study was to evaluate the outcomes of a novel transcutaneous electrical nerve stimulation device compared with those of other standard nonoperative modalities for the treatment of osteoarthritis of the knee.

  6. [Descending long-loop reflexes in the human spinal cord I. Facilitation of the triceps surae H reflex following stimulation of forelimb afferences (author's transl)].

    PubMed

    Meinck, H M

    1976-09-01

    The H reflex in the triceps surae muscle was elicited by just supraliminal stimulation of the tibial nerve. It was conditioned by paired impulses to the brachial plexus or the forelimb nerves and in some cases to other sites of the body. With a conditioning test interval of 32-47 msec a facilitation occurred which reached its maximum at about 80 msec and lasted for about 400 msec. The facilitation evoked by ipsilateral conditioning had a shorter latency than that from contralateral (ipsilateral: 32-42 msec, contralateral; 37-47 msec). The facilitation at the optimum interval (about 80 msec) ranged between 1;5 and 11.3 times of the control values. Ipsilateral conditioning was slightly more effective than the contralateral one (Fig. 1, 2). Stimulation of different forelimb nerves at an interval of 80 msec showed only insignificant differences in the amount of facilitation but was more effective than skin stimulation in the most cases (Fig. 3). Varying the intensity of the conditioning stimulus showed that facilitation occurred with just perceptable stimuli but it became more pronounced as soon as pain threshold (2-3 time of perception threshold) was exceeded (Fig. 3). This suggests that facilitation was mainly due to activation of nociceptor afferents. From the onset of facilitation and the conduction velocities of the respective forelimb and hindlimb afferents (cf. 6) a central reflex lantency of about 43 msec was calculated. To get further insight into the central connections of the reflex loop the H reflex was conditioned by paravertebral stimulation at C5 and L1 level. Both stimuli caused a distinct facilitation. However, the latency of the onset was 10-15 msec shorter with lumbar stimulation than with cervical stimulation. This and the similar time course of facilitation seen in animal experiments (12) suggest that an early part of facilitation is mediated via a descending propriospinal pathway. The major part, however, is supposed to be mediated via supraspinal

  7. Neural adaptations to electrical stimulation strength training.

    PubMed

    Hortobágyi, Tibor; Maffiuletti, Nicola A

    2011-10-01

    This review provides evidence for the hypothesis that electrostimulation strength training (EST) increases the force of a maximal voluntary contraction (MVC) through neural adaptations in healthy skeletal muscle. Although electrical stimulation and voluntary effort activate muscle differently, there is substantial evidence to suggest that EST modifies the excitability of specific neural paths and such adaptations contribute to the increases in MVC force. Similar to strength training with voluntary contractions, EST increases MVC force after only a few sessions with some changes in muscle biochemistry but without overt muscle hypertrophy. There is some mixed evidence for spinal neural adaptations in the form of an increase in the amplitude of the interpolated twitch and in the amplitude of the volitional wave, with less evidence for changes in spinal excitability. Cross-sectional and exercise studies also suggest that the barrage of sensory and nociceptive inputs acts at the cortical level and can modify the motor cortical output and interhemispheric paths. The data suggest that neural adaptations mediate initial increases in MVC force after short-term EST.

  8. A computational model for epidural electrical stimulation of spinal sensorimotor circuits.

    PubMed

    Capogrosso, Marco; Wenger, Nikolaus; Raspopovic, Stanisa; Musienko, Pavel; Beauparlant, Janine; Bassi Luciani, Lorenzo; Courtine, Grégoire; Micera, Silvestro

    2013-12-04

    Epidural electrical stimulation (EES) of lumbosacral segments can restore a range of movements after spinal cord injury. However, the mechanisms and neural structures through which EES facilitates movement execution remain unclear. Here, we designed a computational model and performed in vivo experiments to investigate the type of fibers, neurons, and circuits recruited in response to EES. We first developed a realistic finite element computer model of rat lumbosacral segments to identify the currents generated by EES. To evaluate the impact of these currents on sensorimotor circuits, we coupled this model with an anatomically realistic axon-cable model of motoneurons, interneurons, and myelinated afferent fibers for antagonistic ankle muscles. Comparisons between computer simulations and experiments revealed the ability of the model to predict EES-evoked motor responses over multiple intensities and locations. Analysis of the recruited neural structures revealed the lack of direct influence of EES on motoneurons and interneurons. Simulations and pharmacological experiments demonstrated that EES engages spinal circuits trans-synaptically through the recruitment of myelinated afferent fibers. The model also predicted the capacity of spatially distinct EES to modulate side-specific limb movements and, to a lesser extent, extension versus flexion. These predictions were confirmed during standing and walking enabled by EES in spinal rats. These combined results provide a mechanistic framework for the design of spinal neuroprosthetic systems to improve standing and walking after neurological disorders.

  9. Neck muscle afferents influence oromotor and cardiorespiratory brainstem neural circuits.

    PubMed

    Edwards, I J; Lall, V K; Paton, J F; Yanagawa, Y; Szabo, G; Deuchars, S A; Deuchars, J

    2015-01-01

    Sensory information arising from the upper neck is important in the reflex control of posture and eye position. It has also been linked to the autonomic control of the cardiovascular and respiratory systems. Whiplash associated disorders (WAD) and cervical dystonia, which involve disturbance to the neck region, can often present with abnormalities to the oromotor, respiratory and cardiovascular systems. We investigated the potential neural pathways underlying such symptoms. Simulating neck afferent activity by electrical stimulation of the second cervical nerve in a working heart brainstem preparation (WHBP) altered the pattern of central respiratory drive and increased perfusion pressure. Tracing central targets of these sensory afferents revealed projections to the intermedius nucleus of the medulla (InM). These anterogradely labelled afferents co-localised with parvalbumin and vesicular glutamate transporter 1 indicating that they are proprioceptive. Anterograde tracing from the InM identified projections to brain regions involved in respiratory, cardiovascular, postural and oro-facial behaviours--the neighbouring hypoglossal nucleus, facial and motor trigeminal nuclei, parabrachial nuclei, rostral and caudal ventrolateral medulla and nucleus ambiguus. In brain slices, electrical stimulation of afferent fibre tracts lateral to the cuneate nucleus monosynaptically excited InM neurones. Direct stimulation of the InM in the WHBP mimicked the response of second cervical nerve stimulation. These results provide evidence of pathways linking upper cervical sensory afferents with CNS areas involved in autonomic and oromotor control, via the InM. Disruption of these neuronal pathways could, therefore, explain the dysphagic and cardiorespiratory abnormalities which may accompany cervical dystonia and WAD.

  10. Electrical Stimulation to Enhance Spinal Fusion: A Systematic Review

    PubMed Central

    Park, Paul; Lau, Darryl; Brodt, Erika D.; Dettori, Joseph R.

    2014-01-01

    Study Design Systematic review. Clinical Questions Compared with no stimulation, does electrical stimulation promote bone fusion after lumbar spinal fusion procedures? Does the effect differ based on the type of electrical stimulation used? Methods Electronic databases and reference lists of key articles were searched up to October 15, 2013, to identify randomized controlled trials (RCTs) comparing the effect of electrical stimulation to no electrical stimulation on fusion rates after lumbar spinal fusion for the treatment of degenerative disease. Two independent reviewers assessed the strength of evidence using the Grades of Recommendation Assessment, Development and Evaluation (GRADE) criteria. Results Six RCTs met the inclusion criteria. The following types of electrical stimulation were investigated: direct current (three studies), pulsed electromagnetic field (three studies), and capacitive coupling (one study). The control groups consisted of no stimulation (two studies) or placebo (four studies). Marked heterogeneity in study populations, characteristics, and design prevented a meta-analysis. Regardless of the type of electrical stimulation used, cumulative incidences of fusion varied widely across the RCTs, ranging from 35.4 to 90.6% in the intervention groups and from 33.3 to 81.9% in the control groups across 9 to 24 months of follow-up. Similarly, when stratified by the type of electrical stimulation used, fusion outcomes from individual studies varied, leading to inconsistent and conflicting results. Conclusion Given the inconsistency in study results, possibly due to heterogeneity in study populations/characteristics and quality, we are unable to conclude that electrical stimulation results in better fusion outcomes compared with no stimulation. The overall strength of evidence for the conclusions is low. PMID:25278882

  11. A figure of merit for neural electrical stimulation circuits.

    PubMed

    Kolbl, Florian; Demosthenous, Andreas

    2015-01-01

    Electrical stimulators are widely used in neuro-prostheses. Many different implementations exist. However, no quantitative ranking criterion is available to allow meaningful comparison of the various stimulation circuits and systems to aid the designer. This paper presents a novel Figure of Merit (FOM) dedicated to stimulation circuits and systems. The proposed optimization performance metric takes into account tissue safety conditions and energy efficiency which can be evaluated by measurement. The FOM is used to rank several stimulator circuits and systems.

  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 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...

  14. 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...

  15. Contribution of hind limb flexor muscle afferents to the timing of phase transitions in the cat step cycle.

    PubMed

    Hiebert, G W; Whelan, P J; Prochazka, A; Pearson, K G

    1996-03-01

    1. In this investigation, we tested the hypothesis that muscle spindle afferents signaling the length of hind-leg flexor muscles are involved in terminating extensor activity and initiating flexion during walking. The hip flexor muscle iliopsoas (IP) and the ankle flexors tibialis anterior (TA) and extensor digitorum longus (EDL) were stretched or vibrated at various phases of the step cycle in spontaneously walking decerebrate cats. Changes in electromyogram amplitude, duration, and timing were then examined. The effects of electrically stimulating group I and II afferents in the nerves to TA and EDL also were examined. 2. Stretch of the individual flexor muscles (IP, TA, or EDL) during the stance phase reduced the duration of extensor activity and promoted the onset of flexor burst activity. The contralateral step cycle also was affected by the stretch, the duration of flexor activity being shortened and extensor activity occurring earlier. Therefore, stretch of the flexor muscles during the stance phase reset the locomotor rhythm to flexion ipsilaterally and extension contralaterally. 3. Results of electrically stimulating the afferents from the TA and EDL muscles suggested that different groups of afferents were responsible for the resetting of the step cycle. Stimulation of the TA nerve reset the locomotor step cycle when the stimulus intensity was in the group II range (2-5 xT). By contrast, stimulation of the EDL nerve generated strong resetting of the step cycle in the range of 1.2-1.4 xT, where primarily the group Ia afferents from the muscle spindles would be activated. 4. Vibration of IP or EDL during stance reduced the duration of the extensor activity by similar amounts to that produced by muscle stretch or by electrical stimulation of EDL at group Ia strengths. This suggests that the group Ia afferents from IP and EDL are capable of resetting the locomotor pattern generator. Vibration of TA did not affect the locomotor rhythm. 5. Stretch of IP or

  16. Effects of transcutaneous electrical nerve stimulation (TENS) on spasticity in patients with hemiplegia.

    PubMed

    Potisk, K P; Gregoric, M; Vodovnik, L

    1995-09-01

    The effect of afferent cutaneous electrical stimulation on the spasticity of leg muscles was studied in 20 patients with chronic hemiplegia after stroke. Stimulation electrodes were placed over the sural nerve of the affected limb. The standard method of cutaneous stimulation, TENS with impulse frequency of 100 Hz, was applied. The tonus of the leg muscles was measured by means of an electrohydraulic measuring brace. The EMG stretch reflex activity of the tibialis anterior and triceps surae muscles was detected by surface electrodes and recorded simultaneously with the measured biomechanical parameters. In 18 out of 20 patients, a mild but statistically significant decrease in resistive torques at all frequencies of passive ankle movements was recorded following 20 min of TENS application. The decrease in resistive torque was often (but not always) accompanied by a decrease in reflex EMG activity. This effect of TENS persisted up to 45 min after the end of TENS. The results of the study support the hypothesis that TENS applied to the sural nerve may induce short-term post-stimulation inhibitory effects on the abnormally enhanced stretch reflex activity in spasticity of cerebral origin.

  17. Toward rational design of electrical stimulation strategies for epilepsy control

    PubMed Central

    Sunderam, Sridhar; Gluckman, Bruce; Reato, Davide; Bikson, Marom

    2009-01-01

    Electrical stimulation is emerging as a viable alternative for epilepsy patients whose seizures are not alleviated by drugs or surgery. Its attractions are temporal and spatial specificity of action, flexibility of waveform parameters and timing, and the perception that its effects are reversible unlike resective surgery. However, despite significant advances in our understanding of mechanisms of neural electrical stimulation, clinical electrotherapy for seizures relies heavily on empirical tuning of parameters and protocols. We highlight concurrent treatment goals with potentially conflicting design constraints that must be resolved when formulating rational strategies for epilepsy electrotherapy: namely seizure reduction versus cognitive impairment, stimulation efficacy versus tissue safety, and mechanistic insight versus clinical pragmatism. First, treatment markers, objectives, and metrics relevant to electrical stimulation for epilepsy are discussed from a clinical perspective. Then the experimental perspective is presented, with the biophysical mechanisms and modalities of open-loop electrical stimulation, and the potential benefits of closed-loop control for epilepsy. PMID:19926525

  18. Effects of transcutaneous electrical nerve stimulation on the H-reflex of muscles of different fibre type composition.

    PubMed

    Goulet, C G; Arsenault, A B; Bourbonnais, D; Levin, M F

    1997-09-01

    Differential effects of repetitive stimulation of low threshold afferents on both the recruitment threshold and motoneuronal excitability of type I and type II motor units have been demonstrated. The present study was aimed at further investigating the differential effects of 30 minutes of transcutaneous electrical nerve stimulation (TENS) on the H-reflex amplitude (Hmax/2) of the Soleus (SO), gastrocnemius lateralis (GL) and medialis (GM) muscles. Eleven healthy subjects were tested in order to evaluate the effects of TENS on either the common peroneal (CPN), saphenous or sural nerve. The experimental session consisted of three consecutive 45 min periods. Within each of these periods, H-reflexes were recorded before, during and after the TENS was applied. It was hypothesized that repetitive low threshold afferent stimulation would either have inhibitory or facilitatory effects on the H-reflex amplitude of the SO or gastrocnemii muscles respectively. Non-parametric Friedman ANOVAs revealed a significant tendency (p < 0.05) toward inhibition of the H-reflex amplitude of the SO and GL muscle during TENS applied over either the CPN or sural nerve, as well as that of the GM during repetitive stimulation of the saphenous nerve. Although the present study failed to reveal any differential effects of TENS on the H-reflex amplitude of muscle on different fibre type content, the significant decrease in H-reflex observed on the triceps surae muscles during TENS applied over the CPN might have promising clinical outcomes for hyperreflexive subjects.

  19. Vascular effects of free radicals generated by electrical stimulation

    SciTech Connect

    Lamb, F.S.; Webb, R.C.

    1984-11-01

    Electrical field stimulation (9 V, 1.0 ms, 4 Hz) of isolated segments of rat tail arteries and dog coronary arteries inhibits contractile response to exogenous norephinephrine and elevated potassium concentration. This inhibitory effect of electrical stimulation is blocked by various agents that alter oxygen metabolism: superoxide dismutase, catalase, glutathione, ascorbate, and dimethyl sulfoxide. The observations suggest that the inhibitory effect is due to an action of oxygen free radical metabolites that are generated by the electrical stimulation of the oxygen-rich buffer. These free radical metabolites have two actions: 1) they oxidize drugs in the experimental system, and 2) they exert a direct inhbitory action on vascular smooth muscle.

  20. Design of electrical stimulation bioreactors for cardiac tissue engineering.

    PubMed

    Tandon, N; Marsano, A; Cannizzaro, C; Voldman, J; Vunjak-Novakovic, G

    2008-01-01

    Electrical stimulation has been shown to improve functional assembly of cardiomyocytes in vitro for cardiac tissue engineering. Carbon electrodes were found in past studies to have the best current injection characteristics. The goal of this study was to develop rational experimental design principles for the electrodes and stimulation regime, in particular electrode configuration, electrode ageing, and stimulation amplitude. Carbon rod electrodes were compared via electrochemical impedance spectroscopy (EIS) and we identified a safety range of 0 to 8 V/cm by comparing excitation thresholds and maximum capture rates for neonatal rat cardiomyocytes cultured with electrical stimulation. We conclude with recommendations for studies involving carbon electrodes for cardiac tissue engineering.

  1. Design of Electrical Stimulation Bioreactors for Cardiac Tissue Engineering

    PubMed Central

    Tandon, N.; Marsano, A.; Cannizzaro, C.; Voldman, J.; Vunjak-Novakovic, G.

    2009-01-01

    Electrical stimulation has been shown to improve functional assembly of cardiomyocytes in vitro for cardiac tissue engineering. Carbon electrodes were found in past studies to have the best current injection characteristics. The goal of this study was to develop rational experimental design principles for the electrodes and stimulation regime, in particular electrode configuration, electrode ageing, and stimulation amplitude. Carbon rod electrodes were compared via electrochemical impedance spectroscopy (EIS) and we identified a safety range of 0 to 8 V/cm by comparing excitation thresholds and maximum capture rates for neonatal rat cardiomyocytes cultured with electrical stimulation. We conclude with recommendations for studies involving carbon electrodes for cardiac tissue engineering. PMID:19163486

  2. Activation of transient receptor potential vanilloid 2-expressing primary afferents stimulates synaptic transmission in the deep dorsal horn of the rat spinal cord and elicits mechanical hyperalgesia.

    PubMed

    Petitjean, Hugues; Hugel, Sylvain; Barthas, Florent; Bohren, Yohann; Barrot, Michel; Yalcin, Ipek; Schlichter, Rémy

    2014-10-01

    Probenecid, an agonist of transient receptor vanilloid (TRPV) type 2, was used to evaluate the effects of TRPV2 activation on excitatory and inhibitory synaptic transmission in the dorsal horn (DH) of the rat spinal cord and on nociceptive reflexes induced by thermal heat and mechanical stimuli. The effects of probenecid were compared with those of capsaicin, a TRPV1 agonist. Calcium imaging experiments on rat dorsal root ganglion (DRG) and DH cultures indicated that functional TRPV2 and TRPV1 were expressed by essentially non-overlapping subpopulations of DRG neurons, but were absent from DH neurons and DH and DRG glial cells. Pretreatment of DRG cultures with small interfering RNAs against TRPV2 suppressed the responses to probenecid. Patch-clamp recordings from spinal cord slices showed that probenecid and capsaicin increased the frequencies of spontaneous excitatory postsynaptic currents (sEPSCs) and spontaneous inhibitory postsynaptic currents in a subset of laminae III-V neurons. In contrast to capsaicin, probenecid failed to stimulate synaptic transmission in lamina II. Intrathecal or intraplantar injections of probenecid induced mechanical hyperalgesia/allodynia without affecting nociceptive heat responses. Capsaicin induced both mechanical hyperalgesia/allodynia and heat hyperalgesia. Activation of TRPV1 or TRPV2 in distinct sets of primary afferents increased the sEPSC frequencies in a largely common population of DH neurons in laminae III-V, and might underlie the development of mechanical hypersensitivity following probenecid or capsaicin treatment. However, only TRPV1-expressing afferents facilitated excitatory and/or inhibitory transmission in a subpopulation of lamina II neurons, and this phenomenon might be correlated with the induction of thermal heat hyperalgesia.

  3. Frequency overlap between electric and acoustic stimulation and speech-perception benefit in patients with combined electric and acoustic stimulation

    PubMed Central

    Zhang, Ting; Spahr, Anthony J.; Dorman, Michael F.

    2010-01-01

    Objectives Our aim was to assess, for patients with a cochlear implant in one ear and low-frequency acoustic hearing in the contralateral ear, whether reducing the overlap in frequencies conveyed in the acoustic signal and those analyzed by the cochlear implant speech processor would improve speech recognition. Design The recognition of monosyllabic words in quiet and sentences in noise was evaluated in three listening configurations: electric stimulation alone, acoustic stimulation alone, and combined electric and acoustic stimulation. The acoustic stimuli were either unfiltered or low-pass (LP) filtered at 250 Hz, 500 Hz, or 750 Hz. The electric stimuli were either unfiltered or high-pass (HP) filtered at 250 Hz, 500 Hz or 750 Hz. In the combined condition the unfiltered acoustic signal was paired with the unfiltered electric signal, the 250 LP acoustic signal was paired with the 250 Hz HP electric signal, the 500 Hz LP acoustic signal was paired with the 500 Hz HP electric signal and the 750 Hz LP acoustic signal was paired with the 750 Hz HP electric signal. Results For both acoustic and electric signals performance increased as the bandwith increased. The highest level of performance in the combined condition was observed in the unfiltered acoustic plus unfiltered electric condition. Conclusions Reducing the overlap in frequency representation between acoustic and electric stimulation does not increase speech understanding scores for patients who have residual hearing in the ear contralateral to the implant. We find that acoustic information below 250 Hz significantly improves performance for patients who combine electric and acoustic stimulation and accounts for the majority of the speech-perception benefit when acoustic stimulation is combined with electric stimulation. PMID:19915474

  4. Modulation of fear extinction processes using transcranial electrical stimulation

    PubMed Central

    Abend, R; Jalon, I; Gurevitch, G; Sar-el, R; Shechner, T; Pine, D S; Hendler, T; Bar-Haim, Y

    2016-01-01

    Research associates processes of fear conditioning and extinction with treatment of anxiety and stress-related disorders. Manipulation of these processes may therefore be beneficial for such treatment. The current study examines the effects of electrical brain stimulation on fear extinction processes in healthy humans in order to assess its potential relevance for treatment enhancement. Forty-five participants underwent a 3-day fear conditioning and extinction paradigm. Electrical stimulation targeting the medial prefrontal cortex was applied during the extinction-learning phase (Day 2). Participants were randomly assigned to three stimulation conditions: direct-current (DC) stimulation, aimed at enhancing extinction-learning; low-frequency alternating-current (AC) stimulation, aimed at interfering with reconsolidation of the activated fear memory; and sham stimulation. The effect of stimulation on these processes was assessed in the subsequent extinction recall phase (Day 3), using skin conductance response and self-reports. Results indicate that AC stimulation potentiated the expression of fear response, whereas DC stimulation led to overgeneralization of fear response to non-reinforced stimuli. The current study demonstrates the capability of electrical stimulation targeting the medial prefrontal cortex to modulate fear extinction processes. However, the stimulation parameters tested here yielded effects opposite to those anticipated and could be clinically detrimental. These results highlight the potential capacity of stimulation to manipulate processes relevant for treatment of anxiety and stress-related disorders, but also emphasize the need for additional research to identify delivery parameters to enable its translation into clinical practice. Clinical trial identifiers: Modulation of Fear Extinction Processes Using Transcranial Electrical Stimulation; https://clinicaltrials.gov/show/NCT02723188; NCT02723188 NCT02723188. PMID:27727241

  5. Optimization of electrical stimulation parameters for cardiac tissue engineering.

    PubMed

    Tandon, Nina; Marsano, Anna; Maidhof, Robert; Wan, Leo; Park, Hyoungshin; Vunjak-Novakovic, Gordana

    2011-06-01

    In vitro application of pulsatile electrical stimulation to neonatal rat cardiomyocytes cultured on polymer scaffolds has been shown to improve the functional assembly of cells into contractile engineered cardiac tissues. However, to date, the conditions of electrical stimulation have not been optimized. We have systematically varied the electrode material, amplitude and frequency of stimulation to determine the conditions that are optimal for cardiac tissue engineering. Carbon electrodes, exhibiting the highest charge-injection capacity and producing cardiac tissues with the best structural and contractile properties, were thus used in tissue engineering studies. Engineered cardiac tissues stimulated at 3 V/cm amplitude and 3 Hz frequency had the highest tissue density, the highest concentrations of cardiac troponin-I and connexin-43 and the best-developed contractile behaviour. These findings contribute to defining bioreactor design specifications and electrical stimulation regime for cardiac tissue engineering.

  6. Optimization of Electrical Stimulation Parameters for Cardiac Tissue Engineering

    PubMed Central

    Tandon, Nina; Marsano, Anna; Maidhof, Robert; Wan, Leo; Park, Hyoungshin; Vunjak-Novakovic, Gordana

    2010-01-01

    In vitro application of pulsatile electrical stimulation to neonatal rat cardiomyocytes cultured on polymer scaffolds has been shown to improve the functional assembly of cells into contractile cardiac tissue constrcuts. However, to date, the conditions of electrical stimulation have not been optimized. We have systematically varied the electrode material, amplitude and frequency of stimulation, to determine the conditions that are optimal for cardiac tissue engineering. Carbon electrodes, exhibiting the highest charge-injection capacity and producing cardiac tissues with the best structural and contractile properties, and were thus used in tissue engineering studies. Cardiac tissues stimulated at 3V/cm amplitude and 3Hz frequency had the highest tissue density, the highest concentrations of cardiac troponin-I and connexin-43, and the best developed contractile behavior. These findings contribute to defining bioreactor design specifications and electrical stimulation regime for cardiac tissue engineering. PMID:21604379

  7. Study of Driving Fatigue Alleviation by Transcutaneous Acupoints Electrical Stimulations

    PubMed Central

    Wang, Fuwang; Wang, Hong

    2014-01-01

    Driving fatigue is more likely to bring serious safety trouble to traffic. Therefore, accurately and rapidly detecting driving fatigue state and alleviating fatigue are particularly important. In the present work, the electrical stimulation method stimulating the Láogóng point (劳宫PC8) of human body is proposed, which is used to alleviate the mental fatigue of drivers. The wavelet packet decomposition (WPD) is used to extract θ, α, and β subbands of drivers' electroencephalogram (EEG) signals. Performances of the two algorithms (θ + α)/(α + β) and θ/β are also assessed as possible indicators for fatigue detection. Finally, the differences between the drivers with electrical stimulation and normal driving are discussed. It is shown that stimulating the Láogóng point (劳宫PC8) using electrical stimulation method can alleviate driver fatigue effectively during longtime driving. PMID:25254242

  8. A CONTINUED INVESTIGATION OF ELECTRICALLY STIMULATED FABRIC FILTRATION

    EPA Science Inventory

    The report summarizes three experiments performed by Southern Research Institute under a cooperative agreement with EPA. First was a demonstration of electrostatically stimulated fabric filtration (ESFF) used to collect particulate matter (PM) from fossil fuel electrical power pl...

  9. Differential stimulation of the retina with subretinally injected exogenous neurotransmitter: A biomimetic alternative to electrical stimulation

    NASA Astrophysics Data System (ADS)

    Rountree, Corey M.; Inayat, Samsoon; Troy, John B.; Saggere, Laxman

    2016-12-01

    Subretinal stimulation of the retina with neurotransmitters, the normal means of conveying visual information, is a potentially better alternative to electrical stimulation widely used in current retinal prostheses for treating blindness from photoreceptor degenerative diseases. Yet, no subretinal electrical or chemical stimulation study has stimulated the OFF and ON pathways differentially through inner retinal activation. Here, we demonstrate the feasibility of differentially stimulating retinal ganglion cells (RGCs) through the inner nuclear layer of the retina with glutamate, a primary neurotransmitter chemical, in a biomimetic way. We show that controlled pulsatile delivery of glutamate into the subsurface of explanted wild-type rat retinas elicits highly localized simultaneous inhibitory and excitatory spike rate responses in OFF and ON RGCs. We also present the spatiotemporal characteristics of RGC responses to subretinally injected glutamate and the therapeutic stimulation parameters. Our findings could pave the way for future development of a neurotransmitter-based subretinal prosthesis offering more naturalistic vision and better visual acuity than electrical prostheses.

  10. Selective Activation of Neuronal Targets With Sinusoidal Electric Stimulation

    PubMed Central

    Freeman, Daniel K.; Eddington, Donald K.; Rizzo, Joseph F.

    2010-01-01

    Electric stimulation of the CNS is being evaluated as a treatment modality for a variety of neurological, psychiatric, and sensory disorders. Despite considerable success in some applications, existing stimulation techniques offer little control over which cell types or neuronal substructures are activated by stimulation. The ability to more precisely control neuronal activation would likely improve the clinical outcomes associated with these applications. Here, we show that specific frequencies of sinusoidal stimulation can be used to preferentially activate certain retinal cell types: photoreceptors are activated at 5 Hz, bipolar cells at 25 Hz, and ganglion cells at 100 Hz. In addition, low-frequency stimulation (≤25 Hz) did not activate passing axons but still elicited robust synaptically mediated responses in ganglion cells; therefore, elicited neural activity is confined to within a focal region around the stimulating electrode. Our results suggest that sinusoidal stimulation provides significantly improved control over elicited neural activity relative to conventional pulsatile stimulation. PMID:20810683

  11. Assessment of nerve morphology in nerve activation during electrical stimulation

    NASA Astrophysics Data System (ADS)

    Gomez-Tames, Jose; Yu, Wenwei

    2013-10-01

    The distance between nerve and stimulation electrode is fundamental for nerve activation in Transcutaneous Electrical Stimulation (TES). However, it is not clear the need to have an approximate representation of the morphology of peripheral nerves in simulation models and its influence in the nerve activation. In this work, depth and curvature of a nerve are investigated around the middle thigh. As preliminary result, the curvature of the nerve helps to reduce the simulation amplitude necessary for nerve activation from far field stimulation.

  12. Afferent control of human stance and gait: evidence for blocking of group I afferents during gait.

    PubMed

    Dietz, V; Quintern, J; Berger, W

    1985-01-01

    The cerebral potentials (c.p.) evoked by electrical stimulation of the tibial nerve during stance and in the various phases of gait of normal subjects were compared with the c.p. and leg muscle e.m.g. responses evoked by perturbations of stance and gait. Over the whole step cycle of gait the c.p. evoked by an electrical stimulus were of smaller amplitude (3 microV and 9 microV, respectively) than that seen in the stance condition, and appeared with a longer latency (mean times to first positive peak: 63 and 43 ms, respectively). When the electrical stimulus was applied during stance after ischaemic blockade of group I afferents, the c.p. were similar to those evoked during gait. The c.p. evoked by perturbations were larger in amplitude than those produced by the electrical stimulus, but similar in latencies in both gait and stance (mean 26 microV and 40 microV; 65 ms and 42 ms, respectively) and configurations. The large gastrocnemius e.m.g. responses evoked by the stance and gait perturbations arose with a latency of 65 to 70 ms. Only in the stance condition was a smaller, shorter latency (40 ms) response seen. It is concluded that during gait the signals of group I afferents are blocked at both segmental and supraspinal levels which was tested by tibial nerve stimulation. It is suggested that the e.m.g. responses induced in the leg by gait perturbations are evoked by group II afferents and mediated via a spinal pathway. The c.p. evoked during gait most probably reflect the processing of this group II input by supraspinal motor centres for the coordination of widespread arm and trunk muscle activation, necessary to restablish body equilibrium.

  13. [Impact of the Overlap Region Between Acoustic and Electric Stimulation].

    PubMed

    Baumann, Uwe; Mocka, Moritz

    2017-02-08

    Patients with residual hearing in the low frequencies and ski-slope hearing loss with partial deafness at medium and high frequencies receive a cochlear implant treatment with electric-acoustic stimulation (EAS, "hybrid" stimulation). In the border region between electric and acoustic stimulation a superposition of the 2 types of stimulation is expected. The area of overlap is determined by the insertion depth of the stimulating electrode and the lower starting point of signal transmission provided by the CI speech processor. The study examined the influence of the variation of the electric-acoustic overlap area on speech perception in noise, whereby the width of the "transmission gap" between the 2 different stimulus modalities was varied by 2 different methods. The results derived from 9 experienced users of the MED-EL Duet 2 speech processor show that the electric-acoustic overlapping area and with it the crossover frequency between the acoustic part and the CI should be adjusted individually. Overall, speech reception thresholds (SRT) showed a wide variation of results in between subjects. Further studies shall investigate whether generalized procedures about the setting of the overlap between electric and acoustic stimulation are reasonable, whereby an increased number of subjects and a longer period of acclimatization prior to the conduction of hearing tests deemed necessary.

  14. Therapeutic electrical stimulation for spasticity: quantitative gait analysis.

    PubMed

    Pease, W S

    1998-01-01

    Improvement in motor function following electrical stimulation is related to strengthening of the stimulated spastic muscle and inhibition of the antagonist. A 26-year-old man with familial spastic paraparesis presented with gait dysfunction and bilateral lower limb spastic muscle tone. Clinically, muscle strength and sensation were normal. He was considered appropriate for a trial of therapeutic electrical stimulation following failed trials of physical therapy and baclofen. No other treatment was used concurrent with the electrical stimulation. Before treatment, quantitative gait analysis revealed 63% of normal velocity and a crouched gait pattern, associated with excessive electromyographic activity in the hamstrings and gastrocnemius muscles. Based on these findings, bilateral stimulation of the quadriceps and anterior compartment musculature was performed two to three times per week for three months. Repeat gait analysis was conducted three weeks after the cessation of stimulation treatment. A 27% increase in velocity was noted associated with an increase in both cadence and right step length. Right hip and bilateral knee stance motion returned to normal (rather than "crouched"). No change in the timing of dynamic electromyographic activity was seen. These findings suggest a role for the use of electrical stimulation for rehabilitation of spasticity. The specific mechanism of this improvement remains uncertain.

  15. Electrical stimulation promotes regeneration of injured oculomotor nerves in dogs

    PubMed Central

    Du, Lei; Yang, Min; Wan, Liang; Wang, Xu-hui; Li, Shi-ting

    2016-01-01

    Functional recovery after oculomotor nerve injury is very poor. Electrical stimulation has been shown to promote regeneration of injured nerves. We hypothesized that electrical stimulation would improve the functional recovery of injured oculomotor nerves. Oculomotor nerve injury models were created by crushing the right oculomotor nerves of adult dogs. Stimulating electrodes were positioned in both proximal and distal locations of the lesion, and non-continuous rectangular, biphasic current pulses (0.7 V, 5 Hz) were administered 1 hour daily for 2 consecutive weeks. Analysis of the results showed that electrophysiological and morphological recovery of the injured oculomotor nerve was enhanced, indicating that electrical stimulation improved neural regeneration. Thus, this therapy has the potential to promote the recovery of oculomotor nerve dysfunction. PMID:27904500

  16. Comparative Evaluation of Tactile Sensation by Electrical and Mechanical Stimulation.

    PubMed

    Yem, Vibol; Kajimoto, Hiroyuki

    2017-01-01

    An electrotactile display is a tactile interface that provides tactile perception by passing electrical current through the surface of the skin. It is actively used instead of mechanical tactile displays for tactile feedback because of several advantages such as its small and thin size, light weight, and high responsiveness. However, the similarities and differences between these sensations is still not clear. This study directly compares the intensity sensation of electrotactile stimulation to that of mechanical stimulation, and investigates the characteristic sensation of anodic and cathodic stimulation. In the experiment, participants underwent a 30 pps electrotactile stimulus every one second to their middle finger, and were asked to match this intensity by adjusting the intensity of a mechanical tactile stimulus to an index finger. The results showed that anodic stimulation mainly produced vibration sensation, whereas cathodic sensation produced both vibration and pressure sensations. Relatively low pressure sensation was also observed for anodic stimulation but it remains low, regardless of the increasing of electrical intensity.

  17. Modeling extracellular electrical stimulation: II. Computational validation and numerical results.

    PubMed

    Tahayori, Bahman; Meffin, Hamish; Dokos, Socrates; Burkitt, Anthony N; Grayden, David B

    2012-12-01

    The validity of approximate equations describing the membrane potential under extracellular electrical stimulation (Meffin et al 2012 J. Neural Eng. 9 065005) is investigated through finite element analysis in this paper. To this end, the finite element method is used to simulate a cylindrical neurite under extracellular stimulation. Laplace's equations with appropriate boundary conditions are solved numerically in three dimensions and the results are compared to the approximate analytic solutions. Simulation results are in agreement with the approximate analytic expressions for longitudinal and transverse modes of stimulation. The range of validity of the equations describing the membrane potential for different values of stimulation and neurite parameters are presented as well. The results indicate that the analytic approach can be used to model extracellular electrical stimulation for realistic physiological parameters with a high level of accuracy.

  18. Interphase gap decreases electrical stimulation threshold of retinal ganglion cells.

    PubMed

    Weitz, A C; Behrend, M R; Humayun, M S; Chow, R H; Weiland, J D

    2011-01-01

    The most common electrical stimulation pulse used in retinal implants is a symmetric biphasic current pulse. Prior electrophysiological studies in peripheral nerve have shown that adding an interphase gap (IPG) between the two phases makes stimulation more efficient. We investigated the effect of IPG duration on retinal ganglion cell (RGC) electrical threshold. We used calcium imaging to measure the activity of RGCs in isolated retina in response to electrical stimulation. By varying IPG duration, we were able to examine the effect of duration on threshold. We further studied this effect by simulating RGC behavior with a Hodgkin-Huxley-type model. Our results indicate that the threshold for electrical activation of RGCs can be reduced by increasing the length of the IPG.

  19. MK-801 protects against neuronal injury induced by electrical stimulation.

    PubMed

    Agnew, W F; McCreery, D B; Yuen, T G; Bullara, L A

    1993-01-01

    The ability of MK-801, a non-competitive N-methyl-D-aspartate receptor antagonist, to protect neurons in the cerebral cortex from injury induced by prolonged electrical stimulation was assessed in cats. Platinum disc electrodes 8.0 mm in diameter and with a surface area of 0.5 cm2 were implanted in the subdural space over the parietal cortex. Ten days after implantation of the electrodes, all animals received continuous stimulation for 7 h using charge-balanced, cathodic-first, controlled current pulses with a charge density of 20 microC/cm2 and a charge/phase of 10 microC/phase. They received either no MK-801, or 0.33 or 5.0 mg/kg (i.v.) administered intravenously, just before the start of the stimulation. Immediately following the stimulation, the animals were perfused and the cerebral cortex examined by light microscopy at eight sites beneath the electrodes. Neuronal damage in the form of shrunken, hyperchromic neurons and perineuronal halos was present only beneath the stimulating electrodes; damage was moderate to severe in stimulated animals that had not received MK-801, slight in animals receiving 0.33 mg/kg, and none to slight in animals receiving 5.0 mg/kg. These results indicate that MK-801, in an apparently dose-dependent fashion, provides substantial but not complete protection against neuronal injury induced by prolonged electrical stimulation. Thus prolonged electrical stimulation can be added to the list of neuropathologic conditions which involve glutamate-induced excitotoxic damage via the N-methyl-D-aspartate receptor. The results also support the hypothesis of neuronal hyperactivity as a principal cause of electrically-induced injury in the central nervous system. The implications for design of protocols for functional electrical stimulation are discussed.

  20. Induction of Long-term Depression-like Plasticity by Pairings of Motor Imagination and Peripheral Electrical Stimulation.

    PubMed

    Jochumsen, Mads; Signal, Nada; Nedergaard, Rasmus W; Taylor, Denise; Haavik, Heidi; Niazi, Imran K

    2015-01-01

    Long-term depression (LTD) and long-term potentiation (LTP)-like plasticity are models of synaptic plasticity which have been associated with memory and learning. The induction of LTD and LTP-like plasticity, using different stimulation protocols, has been proposed as a means of addressing abnormalities in cortical excitability associated with conditions such as focal hand dystonia and stroke. The aim of this study was to investigate whether the excitability of the cortical projections to the tibialis anterior (TA) muscle could be decreased when dorsiflexion of the ankle joint was imagined and paired with peripheral electrical stimulation (ES) of the nerve supplying the antagonist soleus muscle. The effect of stimulus timing was evaluated by comparing paired stimulation timed to reach the cortex before, at and after the onset of imagined movement. Fourteen healthy subjects participated in six experimental sessions held on non-consecutive days. The timing of stimulation delivery was determined offline based on the contingent negative variation (CNV) of electroencephalography brain data obtained during imagined dorsiflexion. Afferent stimulation was provided via a single pulse ES to the peripheral nerve paired, based on the CNV, with motor imagination of ankle dorsiflexion. A significant decrease (P = 0.001) in the excitability of the cortical projection of TA was observed when the afferent volley from the ES of the tibial nerve (TN) reached the cortex at the onset of motor imagination based on the CNV. When TN stimulation was delivered before (P = 0.62), or after (P = 0.23) imagined movement onset there was no significant effect. Nor was a significant effect found when ES of the TN was applied independent of imagined movement (P = 0.45). Therefore, the excitability of the cortical projection to a muscle can be inhibited when ES of the nerve supplying the antagonist muscle is precisely paired with the onset of imagined movement.

  1. Induction of Long-term Depression-like Plasticity by Pairings of Motor Imagination and Peripheral Electrical Stimulation

    PubMed Central

    Jochumsen, Mads; Signal, Nada; Nedergaard, Rasmus W.; Taylor, Denise; Haavik, Heidi; Niazi, Imran K.

    2015-01-01

    Long-term depression (LTD) and long-term potentiation (LTP)-like plasticity are models of synaptic plasticity which have been associated with memory and learning. The induction of LTD and LTP-like plasticity, using different stimulation protocols, has been proposed as a means of addressing abnormalities in cortical excitability associated with conditions such as focal hand dystonia and stroke. The aim of this study was to investigate whether the excitability of the cortical projections to the tibialis anterior (TA) muscle could be decreased when dorsiflexion of the ankle joint was imagined and paired with peripheral electrical stimulation (ES) of the nerve supplying the antagonist soleus muscle. The effect of stimulus timing was evaluated by comparing paired stimulation timed to reach the cortex before, at and after the onset of imagined movement. Fourteen healthy subjects participated in six experimental sessions held on non-consecutive days. The timing of stimulation delivery was determined offline based on the contingent negative variation (CNV) of electroencephalography brain data obtained during imagined dorsiflexion. Afferent stimulation was provided via a single pulse ES to the peripheral nerve paired, based on the CNV, with motor imagination of ankle dorsiflexion. A significant decrease (P = 0.001) in the excitability of the cortical projection of TA was observed when the afferent volley from the ES of the tibial nerve (TN) reached the cortex at the onset of motor imagination based on the CNV. When TN stimulation was delivered before (P = 0.62), or after (P = 0.23) imagined movement onset there was no significant effect. Nor was a significant effect found when ES of the TN was applied independent of imagined movement (P = 0.45). Therefore, the excitability of the cortical projection to a muscle can be inhibited when ES of the nerve supplying the antagonist muscle is precisely paired with the onset of imagined movement. PMID:26648859

  2. Stimulating the Comfort of Textile Electrodes in Wearable Neuromuscular Electrical Stimulation

    PubMed Central

    Zhou, Hui; Lu, Yi; Chen, Wanzhen; Wu, Zhen; Zou, Haiqing; Krundel, Ludovic; Li, Guanglin

    2015-01-01

    Textile electrodes are becoming an attractive means in the facilitation of surface electrical stimulation. However, the stimulation comfort of textile electrodes and the mechanism behind stimulation discomfort is still unknown. In this study, a textile stimulation electrode was developed using conductive fabrics and then its impedance spectroscopy, stimulation thresholds, and stimulation comfort were quantitatively assessed and compared with those of a wet textile electrode and a hydrogel electrode on healthy subjects. The equivalent circuit models and the finite element models of different types of electrode were built based on the measured impedance data of the electrodes to reveal the possible mechanism of electrical stimulation pain. Our results showed that the wet textile electrode could achieve similar stimulation performance as the hydrogel electrode in motor threshold and stimulation comfort. However, the dry textile electrode was found to have very low pain threshold and induced obvious cutaneous painful sensations during stimulation, in comparison to the wet and hydrogel electrodes. Indeed, the finite element modeling results showed that the activation function along the z direction at the depth of dermis epidermis junction of the dry textile electrode was significantly larger than that of the wet and hydrogel electrodes, thus resulting in stronger activation of pain sensing fibers. Future work will be done to make textile electrodes have similar stimulation performance and comfort as hydrogel electrodes. PMID:26193273

  3. Stimulating the Comfort of Textile Electrodes in Wearable Neuromuscular Electrical Stimulation.

    PubMed

    Zhou, Hui; Lu, Yi; Chen, Wanzhen; Wu, Zhen; Zou, Haiqing; Krundel, Ludovic; Li, Guanglin

    2015-07-16

    Textile electrodes are becoming an attractive means in the facilitation of surface electrical stimulation. However, the stimulation comfort of textile electrodes and the mechanism behind stimulation discomfort is still unknown. In this study, a textile stimulation electrode was developed using conductive fabrics and then its impedance spectroscopy, stimulation thresholds, and stimulation comfort were quantitatively assessed and compared with those of a wet textile electrode and a hydrogel electrode on healthy subjects. The equivalent circuit models and the finite element models of different types of electrode were built based on the measured impedance data of the electrodes to reveal the possible mechanism of electrical stimulation pain. Our results showed that the wet textile electrode could achieve similar stimulation performance as the hydrogel electrode in motor threshold and stimulation comfort. However, the dry textile electrode was found to have very low pain threshold and induced obvious cutaneous painful sensations during stimulation, in comparison to the wet and hydrogel electrodes. Indeed, the finite element modeling results showed that the activation function along the z direction at the depth of dermis epidermis junction of the dry textile electrode was significantly larger than that of the wet and hydrogel electrodes, thus resulting in stronger activation of pain sensing fibers. Future work will be done to make textile electrodes have similar stimulation performance and comfort as hydrogel electrodes.

  4. Stimulation of guinea-pig tracheal afferent fibres by non-isosmotic and low-chloride stimuli and the effect of frusemide.

    PubMed

    Fox, A J; Barnes, P J; Dray, A

    1995-01-01

    1. Inhalation of low-chloride or non-isosmotic solutions evokes cough or reflex bronchoconstriction in humans that is inhibited by frusemide (furosemide), whilst capsaicin-evoked cough is unaffected. Here we have examined the responses of single vagal afferent fibres innervating the isolated guinea-pig trachea to these stimuli, and tested the effect of frusemide on fibre responses. 2. Both distilled water and hypertonic saline applied for 30 s onto identified receptive fields produced marked excitation of all A delta and C fibres tested. Isotonic glucose, a low-chloride solution, was a less potent stimulant and caused excitation in 37% of A delta fibres and 69% of C fibres. There was no difference in the distribution of low-chloride sensitive and insensitive receptive fields. 3. In the presence of frusemide, responses of A delta fibres to isotonic glucose were significantly inhibited to 34.2 +/- 6.2% of the pre-drug control level. However, frusemide was without effect either on responses of A delta fibres to distilled water or hypertonic saline, or on responses of C fibres to capsaicin. 4. These data support a role for tracheo-bronchial A delta and C fibres in airway reflexes evoked by hypotonic, hypertonic and low-chloride stimuli. The protective effect of frusemide against airway responses to low-chloride but not to non-isosmotic solutions may reflect an action on sensory nerve endings.

  5. Electric field stimulated growth of Zn whiskers

    NASA Astrophysics Data System (ADS)

    Niraula, D.; McCulloch, J.; Warrell, G. R.; Irving, R.; Karpov, V. G.; Shvydka, Diana

    2016-07-01

    We have investigated the impact of strong (˜104 V/cm) electric fields on the development of Zn whiskers. The original samples, with considerable whisker infestation were cut from Zn-coated steel floors and then exposed to electric fields stresses for 10-20 hours at room temperature. We used various electric field sources, from charges accumulated in samples irradiated by: (1) the electron beam of a scanning electron microscope (SEM), (2) the electron beam of a medical linear accelerator, and (3) the ion beam of a linear accelerator; we also used (4) the electric field produced by a Van der Graaf generator. In all cases, the exposed samples exhibited a considerable (tens of percent) increase in whiskers concentration compared to the control sample. The acceleration factor defined as the ratio of the measured whisker growth rate over that in zero field, was estimated to approach several hundred. The statistics of lengths of e-beam induced whiskers was found to follow the log-normal distribution known previously for metal whiskers. The observed accelerated whisker growth is attributed to electrostatic effects. These results offer promise for establishing whisker-related accelerated life testing protocols.

  6. Electrical stimulation of a small brain area reversibly disrupts consciousness.

    PubMed

    Koubeissi, Mohamad Z; Bartolomei, Fabrice; Beltagy, Abdelrahman; Picard, Fabienne

    2014-08-01

    The neural mechanisms that underlie consciousness are not fully understood. We describe a region in the human brain where electrical stimulation reproducibly disrupted consciousness. A 54-year-old woman with intractable epilepsy underwent depth electrode implantation and electrical stimulation mapping. The electrode whose stimulation disrupted consciousness was between the left claustrum and anterior-dorsal insula. Stimulation of electrodes within 5mm did not affect consciousness. We studied the interdependencies among depth recording signals as a function of time by nonlinear regression analysis (h(2) coefficient) during stimulations that altered consciousness and stimulations of the same electrode at lower current intensities that were asymptomatic. Stimulation of the claustral electrode reproducibly resulted in a complete arrest of volitional behavior, unresponsiveness, and amnesia without negative motor symptoms or mere aphasia. The disruption of consciousness did not outlast the stimulation and occurred without any epileptiform discharges. We found a significant increase in correlation for interactions affecting medial parietal and posterior frontal channels during stimulations that disrupted consciousness compared with those that did not. Our findings suggest that the left claustrum/anterior insula is an important part of a network that subserves consciousness and that disruption of consciousness is related to increased EEG signal synchrony within frontal-parietal networks.

  7. Electrical stimulation during skill training with a therapeutic glove enhances the induction of cortical plasticity and has a positive effect on motor memory.

    PubMed

    Christova, Monica; Rafolt, Dietmar; Golaszewski, Stefan; Nardone, Raffaele; Gallasch, Eugen

    2014-08-15

    To examine whether afferent stimulation of hand muscles has a facilitating effect on motor performance, learning and cortical excitability, healthy subjects were trained on the grooved pegboard test (GTP) while wearing a mesh glove (MG) with incorporated electrical stimulation. Three study groups (n=12) were compared in a between subjects design, the bare handed (BH), gloved (MG) and gloved with electrical stimulation (MGS) groups. Motor performance was assessed by the GPT completion time across 4 training blocks, and further one block was retested 7 days later to determine the off-line effects. On-line learning was obtained by normalizing the completion time values to the first training block, and off-line learning was obtained by normalizing the retest values to the last training block. Cortical excitability was assessed via single and paired-pulse transcranial magnetic stimulation (TMS) at pre-training, post-training and 30 min post-training. Motor evoked potential recruitment curve, short-latency intracortical inhibition and intracortical facilitation were estimated from the TMS assessments. Motor performance across all 4 training blocks was poor in the MG and MGS groups, while on-line learning was not affected by wearing the glove or by afferent stimulation. However, off-line learning, tested 7 days after training, was improved in the MGS group compared to the MG group. In addition, post-training corticospinal excitability was increased in the MGS group. It can be concluded that afferent stimulation improves off-line learning and thus has a positive effect on motor memory, likely due to LTP-like cortical plasticity in the consolidation phase.

  8. Electrical stimulation therapy for dysphagia: descriptive results of two surveys.

    PubMed

    Crary, Michael A; Carnaby-Mann, Giselle D; Faunce, Allison

    2007-07-01

    Given the paucity of objective information on neuromuscular electrical stimulation approaches to dysphagia therapy, and the expanding utilization of this clinical approach, we designed and conducted two surveys to gather large-scale information regarding reported practice patterns, outcomes, complications, and professional perceptions associated with electrical stimulation approaches to dysphagia therapy. Self-administered questionnaires were mailed to 1000 randomly selected speech-language pathologists in each of two groups: (1) clinicians who had completed a formal electrical stimulation training course and were actively using these techniques, and (2) clinicians who were members of Special Interest Division 13 of the American Speech-Language and Hearing Association. Survey responses were anonymous and no incentive to respond was included. Acceptable response rates were achieved for both surveys (47% and 48%). Both groups of respondents were demographically similar and reported similar practice patterns. Stroke was the most common etiology of dysphagia treated with this approach. The majority of respondents identified no specific dysphagia criteria for application of electrical stimulation, used varied behavioral treatment methods, and did not follow patients beyond therapy. Clinicians reported positive outcomes with no treatment-related complications. Satisfaction with this approach was reported to be high among patients and professionals. Clinicians who did not report using these techniques indicated that they were waiting for more objective information on clinical outcomes and safety. Results of these surveys form an initial description of practice patterns and outcomes associated with electrical stimulation approaches to dysphagia therapy.

  9. Non-invasive neuromuscular electrical stimulation in patients with central nervous system lesions: an educational review.

    PubMed

    Schuhfried, Othmar; Crevenna, Richard; Fialka-Moser, Veronika; Paternostro-Sluga, Tatjana

    2012-02-01

    The aim of this educational review is to provide an overview of the clinical application of transcutaneous electrical stimulation of the extremities in patients with upper motor neurone lesions. In general two methods of electrical stimulation can be distinguished: (i) therapeutic electrical stimulation, and (ii) functional electrical stimulation. Therapeutic electrical stimulation improves neuromuscular functional condition by strengthening muscles, increasing motor control, reducing spasticity, decreasing pain and increasing range of motion. Transcutaneous electrical stimulation may be used for neuromuscular electrical stimulation inducing repetitive muscle contraction, electromyography-triggered neuromuscular electrical stimulation, position-triggered electrical stimulation and subsensory or sensory transcutaneous electric stimulation. Functional electrical stimulation provokes muscle contraction and thereby produces a functionally useful movement during stimulation. In patients with spinal cord injuries or stroke, electrical upper limb neuroprostheses are applied to enhance upper limb and hand function, and electrical lower limb neuroprostheses are applied for restoration of standing and walking. For example, a dropped foot stimulator is used to trigger ankle dorsiflexion to restore gait function. A review of the literature and clinical experience of the use of therapeutic electrical stimulation as well as of functional electrical stimulation in combination with botulinum toxin, exercise therapy and/or splinting are presented. Although the evidence is limited we conclude that neuromuscular electrical stimulation in patients with central nervous system lesions can be an effective modality to improve function, and that combination with other treatments has an additive therapeutic effect.

  10. Why intra-epidermal electrical stimulation achieves stimulation of small fibres selectively: a simulation study

    NASA Astrophysics Data System (ADS)

    Motogi, Jun; Sugiyama, Yukiya; Laakso, Ilkka; Hirata, Akimasa; Inui, Koji; Tamura, Manabu; Muragaki, Yoshihiro

    2016-06-01

    The in situ electric field in the peripheral nerve of the skin is investigated to discuss the selective stimulation of nerve fibres. Coaxial planar electrodes with and without intra-epidermal needle tip were considered as electrodes of a stimulator. From electromagnetic analysis, the tip depth of the intra-epidermal electrode should be larger than the thickness of the stratum corneum, the electrical conductivity of which is much lower than the remaining tissue. The effect of different radii of the outer ring electrode on the in situ electric field is marginal. The minimum threshold in situ electric field (rheobase) for free nerve endings is estimated to be 6.3 kV m-1. The possible volume for electrostimulation, which can be obtained from the in situ electric field distribution, becomes deeper and narrower with increasing needle depth, suggesting that possible stimulation sites may be controlled by changing the needle depth. The injection current amplitude should be adjusted when changing the needle depth because the peak field strength also changes. This study shows that intra-epidermal electrical stimulation can achieve stimulation of small fibres selectively, because Aβ-, Aδ-, and C-fibre terminals are located at different depths in the skin.

  11. Segmental and supraspinal control of synaptic effectiveness of functionally identified muscle afferents in the cat.

    PubMed

    Enríquez, M; Jiménez, I; Rudomin, P

    1996-01-01

    The present investigation documents the patterns of primary afferent depolarization (PAD) of single, functionally identified muscle afferents from the medial gastrocnemius nerve in the intact, anesthetized cat. Classification of the impaled muscle afferents as from muscle spindles or from tendon organs was made according to several criteria, which comprised measurement of conduction velocity and electrical threshold of the peripheral axons, and the maximal frequency followed by the afferent fibers during vibration, as well as the changes in discharge frequency during longitudinal stretch, the projection of the afferent fiber to the motor pool, and, in unparalyzed preparations, the changes in afferent activity during a muscle twitch. In confirmation of a previous study, we found that most muscle spindle afferents (46.1-66.6%, depending on the combination of criteria utilized for receptor classification) had a type A PAD pattern. That is, they were depolarized by stimulation of group I fibers of the posterior biceps and semitendinosus (PBSt) nerve, but not by stimulation of cutaneous nerves (sural and superficial peroneus) or the bulbar reticular formation (RF), which in many cases inhibited the PBSt-induced PAD. In addition, we found a significant fraction of muscle spindle primaries that were depolarized by stimulation of group I PBSt fibers and also by stimulation of the bulbar RF. Stimulation of cutaneous nerves produced PAD in 9.1-31.2% of these fibers (type B PAD pattern) and no PAD in 8.2-15.4% (type C PAD pattern). In contrast to muscle spindle afferents, only the 7.7-15.4% of fibers from tendon organs had a type A PAD pattern, 23-46.1% had a type B and 50-61.5% a type C PAD pattern. These observations suggest that the neuronal circuitry involved in the control of the synaptic effectiveness of muscle spindles and tendon organs is subjected to excitatory as well as to inhibitory influences from cutaneous and reticulospinal fibers. As shown in the accompanying

  12. Tonic and phasic differential GABAergic inhibition of synaptic actions of joint afferents in the cat.

    PubMed

    Rudomin, P; Hernández, E; Lomelí, J

    2007-01-01

    The aim of this study was to examine the functional organization of the spinal neuronal networks activated by myelinated afferent fibers in the posterior articular nerve (PAN) of the anesthetized cat. Particular attention was given to the tonic and phasic GABAa inhibitory modulation of these networks. Changes in the synaptic effectiveness of the joint afferents were inferred from changes in the intraspinal focal potentials produced by electrical stimulation of the PAN. We found that conditioning stimulation of cutaneous nerves (sural, superficial peroneus and saphenous) and of the nucleus raphe magnus often inhibited, in a differential manner, the early and late components of the intraspinal focal potentials produced by stimulation of low and high threshold myelinated PAN afferents, respectively. The degree of the inhibition depended on the strength of both the conditioning and test stimuli and on the segmental level of recording. Conditioning stimulation of group I muscle afferents was less effective, but marked depression of the early and late focal potentials was produced by stimuli exceeding 5 xT. The i.v. injection of 1-2.5 mg/kg of picrotoxin, a GABAa blocker, had relatively minor effects on the early components of the PAN focal potentials, but was able to induce a significant increase of the late components. It also reduced the inhibitory effects of cutaneous and joint nerve conditioning on PAN focal responses. Conditioning autogenetic stimulation with high-frequency trains depressed the PAN focal potentials. The late components of the PAN responses remained depressed several minutes after discontinuing the conditioning train, even after picrotoxin administration. The present observations indicate that the neuronal networks activated by the low threshold PAN afferents show a relatively small post-activation depression and appear to be subjected to a minor tonic inhibitory GABAa control. In contrast, the pathways activated by stimulation of high threshold

  13. Edema and pain reduction using transcutaneous electrical nerve stimulation treatment

    PubMed Central

    Choi, Yeong-Deok; Lee, Jung-Ho

    2016-01-01

    [Purpose] The purpose of this study was to investigate the impact on the edema and pain when applying transcutaneous electrical nerve stimulation. [Subjects and Methods] Eleven patients who were diagnosed with lymphedema were selected as the subjects of the study. The experimental group received transcutaneous electrical nerve stimulation treatment on edema regions three times per week for four weeks. Surface tape measurement was used to measure changes in lower extremity edema. Pain intensity was measured using the visual analog scale. [Results] The edema decrements in the experimental group were significantly larger than those in the control group. The pain decrements in the experimental group were significantly larger than those in the control group. [Conclusion] In conclusion, application of transcutaneous electrical nerve stimulation was confirmed to be effective in reducing edema and pain. PMID:27942125

  14. Pharmacologically Distinct Nicotinic Acetylcholine Receptors Drive Efferent-Mediated Excitation in Calyx-Bearing Vestibular Afferents

    PubMed Central

    Kewin, Kevin; Jordan, Paivi M.; Cameron, Peter; Klapczynski, Marcin; McIntosh, J. Michael; Crooks, Peter A.; Dwoskin, Linda P.; Lysakowski, Anna

    2015-01-01

    Electrical stimulation of vestibular efferent neurons rapidly excites the resting discharge of calyx/dimorphic (CD) afferents. In turtle, this excitation arises when acetylcholine (ACh), released from efferent terminals, directly depolarizes calyceal endings by activating nicotinic ACh receptors (nAChRs). Although molecular biological data from the peripheral vestibular system implicate most of the known nAChR subunits, specific information about those contributing to efferent-mediated excitation of CD afferents is lacking. We sought to identify the nAChR subunits that underlie the rapid excitation of CD afferents and whether they differ from α9α10 nAChRs on type II hair cells that drive efferent-mediated inhibition in adjacent bouton afferents. We recorded from CD and bouton afferents innervating the turtle posterior crista during electrical stimulation of vestibular efferents while applying several subtype-selective nAChR agonists and antagonists. The α9α10 nAChR antagonists, α-bungarotoxin and α-conotoxin RgIA, blocked efferent-mediated inhibition in bouton afferents while leaving efferent-mediated excitation in CD units largely intact. Conversely, 5-iodo-A-85380, sazetidine-A, varenicline, α-conotoxin MII, and bPiDDB (N,N-dodecane-1,12-diyl-bis-3-picolinium dibromide) blocked efferent-mediated excitation in CD afferents without affecting efferent-mediated inhibition in bouton afferents. This pharmacological profile suggested that calyceal nAChRs contain α6 and β2, but not α9, nAChR subunits. Selective blockade of efferent-mediated excitation in CD afferents distinguished dimorphic from calyx afferents by revealing type II hair cell input. Dimorphic afferents differed in having higher mean discharge rates and a mean efferent-mediated excitation that was smaller in amplitude yet longer in duration. Molecular biological data demonstrated the expression of α9 in turtle hair cells and α4 and β2 in associated vestibular ganglia. PMID:25716861

  15. Mapping of electrical muscle stimulation using MRI

    NASA Technical Reports Server (NTRS)

    Adams, Gregory R.; Harris, Robert T.; Woodard, Daniel; Dudley, Gary A.

    1993-01-01

    The pattern of muscle contractile activity elicited by electromyostimulation (EMS) was mapped and compared to the contractile-activity pattern produced by voluntary effort. This was done by examining the patterns and the extent of contrast shift, as indicated by T2 values, im magnetic resonance (MR) images after isometric activity of the left m. quadriceps of human subjects was elicited by EMS (1-sec train of 500-microsec sine wave pulses at 50 Hz) or voluntary effort. The results suggest that, whereas EMS stimulates the same fibers repeatedly, thereby increasing the metabolic demand and T2 values, the voluntary efforts are performed by more diffuse asynchronous activation of skeletal muscle even at forces up to 75 percent of maximal to maintain performance.

  16. Soft Encapsulation of Flexible Electrical Stimulation Implant: Challenges and Innovations

    PubMed Central

    Debelle, Adrien; Hermans, Laura; Bosquet, Maxime; Dehaeck, Sam; Lonys, Laurent; Scheid, Benoit; Nonclercq, Antoine; Vanhoestenberghe, Anne

    2016-01-01

    In this document we discuss the main challenges encountered when producing flexible electrical stimulation implants, and present our approach to solving them for prototype production. We include a study of the optimization of the flexible PCB design, the selection of additive manufacturing materials for the mold, and the chemical compatibility of the different materials. Our approach was tested on a flexible gastro-stimulator as part of the ENDOGES research program. PMID:28078073

  17. Electrically stimulated contractions of Vorticella convallaria

    NASA Astrophysics Data System (ADS)

    Kantha, Deependra; van Winkle, David

    2009-03-01

    The contraction of Vorticella convallaria was triggered by applying a voltage pulse in its host culturing medium. The 50V, 1ms wide pulse was applied across platinum wires separated by 0.7 cm on a microscope slide. The contractions were recorded as cines (image sequences) by a Phantom V5 camera (Vision Research) on a bright field microscope with 20X objective, with the image size of 256 pixels x 128 pixels at 7352 pictures per second. The starting time of the cines was synchronized with the starting of the electrical pulse. We recorded five contractions of each of 12 organisms. The cines were analyzed to obtain the initiation time, defined as the difference in time between the leading edge of the electrical pulse and the first frame showing zooid movement. From multiple contractions of same organism, we found the initiation time is reproducible. In comparing different organisms, we found the average initiation time of 1.73 ms with a standard deviation of 0.63 ms. This research is supported by the state of Florida (MARTECH) and Research Corporation.

  18. Prediction and control of neural responses to pulsatile electrical stimulation.

    PubMed

    Campbell, Luke J; Sly, David James; O'Leary, Stephen John

    2012-04-01

    This paper aims to predict and control the probability of firing of a neuron in response to pulsatile electrical stimulation of the type delivered by neural prostheses such as the cochlear implant, bionic eye or in deep brain stimulation. Using the cochlear implant as a model, we developed an efficient computational model that predicts the responses of auditory nerve fibers to electrical stimulation and evaluated the model's accuracy by comparing the model output with pooled responses from a group of guinea pig auditory nerve fibers. It was found that the model accurately predicted the changes in neural firing probability over time to constant and variable amplitude electrical pulse trains, including speech-derived signals, delivered at rates up to 889 pulses s(-1). A simplified version of the model that did not incorporate adaptation was used to adaptively predict, within its limitations, the pulsatile electrical stimulus required to cause a desired response from neurons up to 250 pulses s(-1). Future stimulation strategies for cochlear implants and other neural prostheses may be enhanced using similar models that account for the way that neural responses are altered by previous stimulation.

  19. Prediction and control of neural responses to pulsatile electrical stimulation

    NASA Astrophysics Data System (ADS)

    Campbell, Luke J.; Sly, David James; O'Leary, Stephen John

    2012-04-01

    This paper aims to predict and control the probability of firing of a neuron in response to pulsatile electrical stimulation of the type delivered by neural prostheses such as the cochlear implant, bionic eye or in deep brain stimulation. Using the cochlear implant as a model, we developed an efficient computational model that predicts the responses of auditory nerve fibers to electrical stimulation and evaluated the model's accuracy by comparing the model output with pooled responses from a group of guinea pig auditory nerve fibers. It was found that the model accurately predicted the changes in neural firing probability over time to constant and variable amplitude electrical pulse trains, including speech-derived signals, delivered at rates up to 889 pulses s-1. A simplified version of the model that did not incorporate adaptation was used to adaptively predict, within its limitations, the pulsatile electrical stimulus required to cause a desired response from neurons up to 250 pulses s-1. Future stimulation strategies for cochlear implants and other neural prostheses may be enhanced using similar models that account for the way that neural responses are altered by previous stimulation.

  20. [Reactions of the neurons of the reticular and ventral anterior nuclei of the optic thalamus to afferent stimulation of different modalities].

    PubMed

    Voloshin, M Ia; Prokopenko, V F

    1975-01-01

    Responses of 146 reticular (R) and 98 ventral anterior (VA) thalamic neurons to electrical stimulation of pads, to light flashes and sound clicks were studied in cats immobilized with d-tubocurarine or myorelaxine. The contralateral forepaw was the most effective receptive field: 24.9% of R and 31.3% of VA investigated neurons responded to its stimulation. Only 4.4% of R and 2.4% of VA neurons responded to the click. Almost all responding neurons reacted to different kind of the applied stimulation by phasic or tonic excitation. Inhibition of background activity was observed after the pads stimulation only in 2.6-4.3% of R and in 1.7%-2.1% of VA neurons. The latency of phasic responses in most neurons ranged: to electrical stimulation of the contralateral forepaw from 6 to 64 ms, to the contralateral hindpaw -- from 11 to 43 ms, to light -- 10-60 ms, and to the click -- 8-60 ms. 75.1-95.6% of R and 68.7-97.6% of VA neurons did not respond at all to different kinds of peripheral stimulation. Of a sample of cells tested to all inputs 25% of R and 47% of VA neurons responded to stimulation of more than one paw; 16% of R and 22% of VA neurons revealed convergence of volleys of different modality. The functional role of this convergence consists in inhibition (more seldom facilitation) of the neuronal response to a testing signal following 40-70 ms after a conditioning one.

  1. Exploring Selective Neural Electrical Stimulation for Upper Limb Function Restoration

    PubMed Central

    Tigra, Wafa; Guiraud, David; Andreu, David; Coulet, Bertrand; Gelis, Anthony; Fattal, Charles; Maciejasz, Pawel; Picq, Chloé; Rossel, Olivier; Teissier, Jacques; Coste, Christine Azevedo

    2016-01-01

    This article introduces a new approach of selective neural electrical stimulation of the upper limb nerves. Median and radial nerves of individuals with tetraplegia are stimulated via a multipolar cuff electrode to elicit movements of wrist and hand in acute conditions during a surgical intervention. Various configurations corresponding to various combinations of a 12-poles cuff electrode contacts are tested. Video recording and electromyographic (EMG) signals recorded via sterile surface electrodes are used to evaluate the selectivity of each stimulation configuration in terms of activated muscles. In this abstract we introduce the protocol and preliminary results will be presented during the conference. PMID:27478571

  2. Electrical stimulation of the motor cortex: theoretical considerations.

    PubMed

    Grandori, F; Rossini, P

    1988-01-01

    The aim of this paper is to present the results of a theoretical analysis of the intracranial fields produced by electrical stimulation of the unexposed motor cortex with surface electrodes in humans. Simulations of a first approximation model of the head indicate that the intensity and the spatial configuration of the intracranial fields can be controlled, to a great extent, by proper choice of the location and of the number of the stimulating electrodes. Fields are shown to be reasonably insensitive to changes of some crucial parameters, like the number of the stimulating electrodes and the ratio between the conductivity of the skull and that of the other tissues.

  3. The usefulness of electrical stimulation for assessing pedicle screw placements.

    PubMed

    Toleikis, J R; Skelly, J P; Carlvin, A O; Toleikis, S C; Bernard, T N; Burkus, J K; Burr, M E; Dorchak, J D; Goldman, M S; Walsh, T R

    2000-08-01

    The purpose of this study was to further establish the efficacy of pedicle screw stimulation as a monitoring technique to avoid nerve root injury during screw placement. The study population consisted of 662 patients in whom 3,409 pedicle screws were placed and tested by electrical stimulation. If stimulation resulted in a myogenic response at a stimulation intensity of 10 mA or less, the placement of the screw was inspected. Inspection was necessary for 3.9% of the screw placements in 15.4% of the study population. None of the patients in the study experienced any new postoperative neurologic deficits. These findings provide guidelines for the interpretation of stimulation data and support the use of this technique as an easy, inexpensive, and quick method to reliably assess screw placements and protecting neurological function.

  4. Connexin36 identified at morphologically mixed chemical/electrical synapses on trigeminal motoneurons and at primary afferent terminals on spinal cord neurons in adult mouse and rat.

    PubMed

    Bautista, W; McCrea, D A; Nagy, J I

    2014-03-28

    Morphologically mixed chemical/electrical synapses at axon terminals, with the electrical component formed by gap junctions, is common in the CNS of lower vertebrates. In mammalian CNS, evidence for morphologically mixed synapses has been obtained in only a few locations. Here, we used immunofluorescence approaches to examine the localization of the neuronally expressed gap junction forming protein connexin36 (Cx36) in relation to the axon terminal marker vesicular glutamate transporter-1 (vglut1) in the spinal cord and the trigeminal motor nucleus (Mo5) of rat and mouse. In adult rodents, immunolabeling for Cx36 appeared exclusively as Cx36-puncta, and was widely distributed at all rostro-caudal levels in most spinal cord laminae and in the Mo5. A high proportion of Cx36-puncta was co-localized with vglut1, forming morphologically mixed synapses on motoneurons, in intermediate spinal cord lamina, and in regions of medial lamina VII, where vglut1-containing terminals associated with Cx36 converged on neurons adjacent to the central canal. Unilateral transection of lumbar dorsal roots reduced immunolabeling of both vglut1 and Cx36 in intermediate laminae and lamina IX. Further, vglut1-terminals displaying Cx36-puncta were contacted by terminals labeled for glutamic acid decarboxylase65, which is known to be contained in presynaptic terminals on large-diameter primary afferents. Developmentally, mixed synapses begin to emerge in the spinal cord only after the second to third postnatal week and thereafter increase to adult levels. Our findings demonstrate that axon terminals of primary afferent origin form morphologically mixed synapses containing Cx36 in broadly distributed areas of adult rodent spinal cord and Mo5.

  5. Electrical stimulation of transplanted motoneurons improves motor unit formation.

    PubMed

    Liu, Yang; Grumbles, Robert M; Thomas, Christine K

    2014-08-01

    Motoneurons die following spinal cord trauma and with neurological disease. Intact axons reinnervate nearby muscle fibers to compensate for the death of motoneurons, but when an entire motoneuron pool dies, there is complete denervation. To reduce denervation atrophy, we have reinnervated muscles in Fisher rats from local transplants of embryonic motoneurons in peripheral nerve. Since growth of axons from embryonic neurons is activity dependent, our aim was to test whether brief electrical stimulation of the neurons immediately after transplantation altered motor unit numbers and muscle properties 10 wk later. All surgical procedures and recordings were done in anesthetized animals. The muscle consequences of motoneuron death were mimicked by unilateral sciatic nerve section. One week later, 200,000 embryonic day 14 and 15 ventral spinal cord cells, purified for motoneurons, were injected into the tibial nerve 10-15 mm from the gastrocnemii muscles as the only neuron source for muscle reinnervation. The cells were stimulated immediately after transplantation for up to 1 h using protocols designed to examine differential effects due to pulse number, stimulation frequency, pattern, and duration. Electrical stimulation that included short rests and lasted for 1 h resulted in higher motor unit counts. Muscles with higher motor unit counts had more reinnervated fibers and were stronger. Denervated muscles had to be stimulated directly to evoke contractions. These results show that brief electrical stimulation of embryonic neurons, in vivo, has long-term effects on motor unit formation and muscle force. This muscle reinnervation provides the opportunity to use patterned electrical stimulation to produce functional movements.

  6. Electrical stimulation of transplanted motoneurons improves motor unit formation

    PubMed Central

    Liu, Yang; Grumbles, Robert M.

    2014-01-01

    Motoneurons die following spinal cord trauma and with neurological disease. Intact axons reinnervate nearby muscle fibers to compensate for the death of motoneurons, but when an entire motoneuron pool dies, there is complete denervation. To reduce denervation atrophy, we have reinnervated muscles in Fisher rats from local transplants of embryonic motoneurons in peripheral nerve. Since growth of axons from embryonic neurons is activity dependent, our aim was to test whether brief electrical stimulation of the neurons immediately after transplantation altered motor unit numbers and muscle properties 10 wk later. All surgical procedures and recordings were done in anesthetized animals. The muscle consequences of motoneuron death were mimicked by unilateral sciatic nerve section. One week later, 200,000 embryonic day 14 and 15 ventral spinal cord cells, purified for motoneurons, were injected into the tibial nerve 10–15 mm from the gastrocnemii muscles as the only neuron source for muscle reinnervation. The cells were stimulated immediately after transplantation for up to 1 h using protocols designed to examine differential effects due to pulse number, stimulation frequency, pattern, and duration. Electrical stimulation that included short rests and lasted for 1 h resulted in higher motor unit counts. Muscles with higher motor unit counts had more reinnervated fibers and were stronger. Denervated muscles had to be stimulated directly to evoke contractions. These results show that brief electrical stimulation of embryonic neurons, in vivo, has long-term effects on motor unit formation and muscle force. This muscle reinnervation provides the opportunity to use patterned electrical stimulation to produce functional movements. PMID:24848463

  7. Electrical and mechanical stimulation of cardiac cells and tissue constructs.

    PubMed

    Stoppel, Whitney L; Kaplan, David L; Black, Lauren D

    2016-01-15

    The field of cardiac tissue engineering has made significant strides over the last few decades, highlighted by the development of human cell derived constructs that have shown increasing functional maturity over time, particularly using bioreactor systems to stimulate the constructs. However, the functionality of these tissues is still unable to match that of native cardiac tissue and many of the stem-cell derived cardiomyocytes display an immature, fetal like phenotype. In this review, we seek to elucidate the biological underpinnings of both mechanical and electrical signaling, as identified via studies related to cardiac development and those related to an evaluation of cardiac disease progression. Next, we review the different types of bioreactors developed to individually deliver electrical and mechanical stimulation to cardiomyocytes in vitro in both two and three-dimensional tissue platforms. Reactors and culture conditions that promote functional cardiomyogenesis in vitro are also highlighted. We then cover the more recent work in the development of bioreactors that combine electrical and mechanical stimulation in order to mimic the complex signaling environment present in vivo. We conclude by offering our impressions on the important next steps for physiologically relevant mechanical and electrical stimulation of cardiac cells and engineered tissue in vitro.

  8. Neuromuscular Electrical Stimulation for Motor Restoration in Hemiplegia

    PubMed Central

    Knutson, Jayme S.; Fu, Michael J.; Sheffler, Lynne R.; Chae, John

    2015-01-01

    Synopsis This article reviews the most common therapeutic and neuroprosthetic applications of neuromuscular electrical stimulation (NMES) for upper and lower extremity stroke rehabilitation. Fundamental NMES principles and purposes in stroke rehabilitation are explained. NMES modalities used for upper and lower limb rehabilitation are described and efficacy studies are summarized. The evidence for peripheral and central mechanisms of action is also summarized. PMID:26522909

  9. Motor unit recruitment during neuromuscular electrical stimulation: a critical appraisal.

    PubMed

    Bickel, C Scott; Gregory, Chris M; Dean, Jesse C

    2011-10-01

    Neuromuscular electrical stimulation (NMES) is commonly used in clinical settings to activate skeletal muscle in an effort to mimic voluntary contractions and enhance the rehabilitation of human skeletal muscles. It is also used as a tool in research to assess muscle performance and/or neuromuscular activation levels. However, there are fundamental differences between voluntary- and artificial-activation of motor units that need to be appreciated before NMES protocol design can be most effective. The unique effects of NMES have been attributed to several mechanisms, most notably, a reversal of the voluntary recruitment pattern that is known to occur during voluntary muscle contractions. This review outlines the assertion that electrical stimulation recruits motor units in a nonselective, spatially fixed, and temporally synchronous pattern. Additionally, it synthesizes the evidence that supports the contention that this recruitment pattern contributes to increased muscle fatigue when compared with voluntary actions and provides some commentary on the parameters of electrical stimulation as well as emerging technologies being developed to facilitate NMES implementation. A greater understanding of how electrical stimulation recruits motor units, as well as the benefits and limitations of its use, is highly relevant when using this tool for testing and training in rehabilitation, exercise, and/or research.

  10. 21 CFR 882.1870 - Evoked response electrical stimulator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Evoked response electrical stimulator. 882.1870 Section 882.1870 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1870 Evoked...

  11. 21 CFR 868.2775 - Electrical peripheral nerve stimulator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... effect of anesthetic drugs and gases. (b) Classification. Class II (performance standards). ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Electrical peripheral nerve stimulator. 868.2775 Section 868.2775 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  12. 21 CFR 868.2775 - Electrical peripheral nerve stimulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... effect of anesthetic drugs and gases. (b) Classification. Class II (performance standards). ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Electrical peripheral nerve stimulator. 868.2775 Section 868.2775 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  13. Neuromuscular Electrical Stimulation for Motor Restoration in Hemiplegia.

    PubMed

    Knutson, Jayme S; Fu, Michael J; Sheffler, Lynne R; Chae, John

    2015-11-01

    This article reviews the most common therapeutic and neuroprosthetic applications of neuromuscular electrical stimulation (NMES) for upper and lower extremity stroke rehabilitation. Fundamental NMES principles and purposes in stroke rehabilitation are explained. NMES modalities used for upper and lower limb rehabilitation are described, and efficacy studies are summarized. The evidence for peripheral and central mechanisms of action is also summarized.

  14. Feedback control of electrode offset voltage during functional electrical stimulation.

    PubMed

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

    2013-08-15

    Control of the electrode offset voltage is an important issue related to the processes of functional electrical stimulation because excess charge accumulation over time damages both the tissue and the electrodes. This paper proposes a new feedback control scheme to regulate the electrode offset voltage to a predetermined reference value. The electrode offset voltage was continuously monitored using a sample-and-hold (S/H) circuit during stimulation and non-stimulation periods. The stimulation current was subsequently adjusted using a proportional-integral (PI) controller to minimise the error between the reference value and the electrode offset voltage. During the stimulation period, the electrode offset voltage was maintained through the S/H circuit, and the PI controller did not affect the amplitude of the stimulation current. In contrast, during the non-stimulation period, the electrode offset voltage was sampled through the S/H circuit and rapidly regulated through the PI controller. The experimental results obtained using a nerve cuff electrode showed that the electrode offset voltage was successfully controlled in terms of the performance specifications, such as the steady- and transient-state responses and the constraint of the controller output. Therefore, the proposed control scheme can potentially be used in various nerve stimulation devices and applications requiring control of the electrode offset voltage.

  15. Electric Stimulation with Sinusoids and White Noise for Neural Prostheses

    PubMed Central

    Freeman, Daniel K.; Rizzo, Joseph F.; Fried, Shelley I.

    2010-01-01

    We are investigating the use of novel stimulus waveforms in neural prostheses to determine whether they can provide more precise control over the temporal and spatial pattern of elicited activity as compared to conventional pulsatile stimulation. To study this, we measured the response of retinal ganglion cells to both sinusoidal and white noise waveforms. The use of cell-attached and whole cell patch clamp recordings allowed the responses to be observed without significant obstruction from the stimulus artifact. Electric stimulation with sinusoids elicited robust responses. White noise analysis was used to derive the linear kernel for the ganglion cell's spiking response as well as for the underlying excitatory currents. These results suggest that in response to electric stimulation, presynaptic retinal neurons exhibit bandpass filtering characteristics with a peak response that occurs 25 ms after onset. The experimental approach demonstrated here may be useful for studying the temporal response properties of other neurons in the CNS. PMID:20582268

  16. Differential stimulation of the retina with subretinally injected exogenous neurotransmitter: A biomimetic alternative to electrical stimulation

    PubMed Central

    Rountree, Corey M.; Inayat, Samsoon; Troy, John B.; Saggere, Laxman

    2016-01-01

    Subretinal stimulation of the retina with neurotransmitters, the normal means of conveying visual information, is a potentially better alternative to electrical stimulation widely used in current retinal prostheses for treating blindness from photoreceptor degenerative diseases. Yet, no subretinal electrical or chemical stimulation study has stimulated the OFF and ON pathways differentially through inner retinal activation. Here, we demonstrate the feasibility of differentially stimulating retinal ganglion cells (RGCs) through the inner nuclear layer of the retina with glutamate, a primary neurotransmitter chemical, in a biomimetic way. We show that controlled pulsatile delivery of glutamate into the subsurface of explanted wild-type rat retinas elicits highly localized simultaneous inhibitory and excitatory spike rate responses in OFF and ON RGCs. We also present the spatiotemporal characteristics of RGC responses to subretinally injected glutamate and the therapeutic stimulation parameters. Our findings could pave the way for future development of a neurotransmitter-based subretinal prosthesis offering more naturalistic vision and better visual acuity than electrical prostheses. PMID:27929043

  17. Closing of venus flytrap by electrical stimulation of motor cells.

    PubMed

    Volkov, Alexander G; Adesina, Tejumade; Jovanov, Emil

    2007-05-01

    Electrical signaling and rapid closure of the carnivorous plant Dionaea muscipula Ellis (Venus flytrap) have been attracting the attention of researchers since XIX century, but the exact mechanism of Venus flytrap closure is still unknown. We found that the electrical stimulus between a midrib and a lobe closes the Venus flytrap leaf by activating motor cells without mechanical stimulation of trigger hairs. The closing time of Venus flytrap by electrical stimulation of motor cells is 0.3 s, the same as mechanically induced closing. The mean electrical charge required for the closure of the Venus flytrap leaf is 13.6 microC. Ion channel blockers such as Ba(2+), TEACl as well as uncouplers such as FCCP, 2,4-dinitrophenol and pentachlorophenol dramatically decrease the speed of the trap closing. Using an ultra-fast data acquisition system with measurements in real time, we found that the action potential in the Venus flytrap has a duration time of about 1.5 ms. Our results demonstrate that electrical stimulation can be used to study mechanisms of fast activity in motor cells of the plant kingdom.

  18. Higher-order power harmonics of pulsed electrical stimulation modulates corticospinal contribution of peripheral nerve stimulation.

    PubMed

    Chen, Chiun-Fan; Bikson, Marom; Chou, Li-Wei; Shan, Chunlei; Khadka, Niranjan; Chen, Wen-Shiang; Fregni, Felipe

    2017-03-03

    It is well established that electrical-stimulation frequency is crucial to determining the scale of induced neuromodulation, particularly when attempting to modulate corticospinal excitability. However, the modulatory effects of stimulation frequency are not only determined by its absolute value but also by other parameters such as power at harmonics. The stimulus pulse shape further influences parameters such as excitation threshold and fiber selectivity. The explicit role of the power in these harmonics in determining the outcome of stimulation has not previously been analyzed. In this study, we adopted an animal model of peripheral electrical stimulation that includes an amplitude-adapted pulse train which induces force enhancements with a corticospinal contribution. We report that the electrical-stimulation-induced force enhancements were correlated with the amplitude of stimulation power harmonics during the amplitude-adapted pulse train. In an exploratory analysis, different levels of correlation were observed between force enhancement and power harmonics of 20-80 Hz (r = 0.4247, p = 0.0243), 100-180 Hz (r = 0.5894, p = 0.0001), 200-280 Hz (r = 0.7002, p < 0.0001), 300-380 Hz (r = 0.7449, p < 0.0001), 400-480 Hz (r = 0.7906, p < 0.0001), 500-600 Hz (r = 0.7717, p < 0.0001), indicating a trend of increasing correlation, specifically at higher order frequency power harmonics. This is a pilot, but important first demonstration that power at high order harmonics in the frequency spectrum of electrical stimulation pulses may contribute to neuromodulation, thus warrant explicit attention in therapy design and analysis.

  19. Higher-order power harmonics of pulsed electrical stimulation modulates corticospinal contribution of peripheral nerve stimulation

    PubMed Central

    Chen, Chiun-Fan; Bikson, Marom; Chou, Li-Wei; Shan, Chunlei; Khadka, Niranjan; Chen, Wen-Shiang; Fregni, Felipe

    2017-01-01

    It is well established that electrical-stimulation frequency is crucial to determining the scale of induced neuromodulation, particularly when attempting to modulate corticospinal excitability. However, the modulatory effects of stimulation frequency are not only determined by its absolute value but also by other parameters such as power at harmonics. The stimulus pulse shape further influences parameters such as excitation threshold and fiber selectivity. The explicit role of the power in these harmonics in determining the outcome of stimulation has not previously been analyzed. In this study, we adopted an animal model of peripheral electrical stimulation that includes an amplitude-adapted pulse train which induces force enhancements with a corticospinal contribution. We report that the electrical-stimulation-induced force enhancements were correlated with the amplitude of stimulation power harmonics during the amplitude-adapted pulse train. In an exploratory analysis, different levels of correlation were observed between force enhancement and power harmonics of 20–80 Hz (r = 0.4247, p = 0.0243), 100–180 Hz (r = 0.5894, p = 0.0001), 200–280 Hz (r = 0.7002, p < 0.0001), 300–380 Hz (r = 0.7449, p < 0.0001), 400–480 Hz (r = 0.7906, p < 0.0001), 500–600 Hz (r = 0.7717, p < 0.0001), indicating a trend of increasing correlation, specifically at higher order frequency power harmonics. This is a pilot, but important first demonstration that power at high order harmonics in the frequency spectrum of electrical stimulation pulses may contribute to neuromodulation, thus warrant explicit attention in therapy design and analysis. PMID:28256638

  20. Coherent anti-Stokes Raman scattering under electric field stimulation

    NASA Astrophysics Data System (ADS)

    Capitaine, Erwan; Ould Moussa, Nawel; Louot, Christophe; Lefort, Claire; Pagnoux, Dominique; Duclère, Jean-René; Kaneyasu, Junya F.; Kano, Hideaki; Duponchel, Ludovic; Couderc, Vincent; Leproux, Philippe

    2016-12-01

    We introduce an experiment using electro-CARS, an electro-optical method based on the combination of ultrabroadband multiplex coherent anti-Stokes Raman scattering (M-CARS) spectroscopy and electric field stimulation. We demonstrate that this method can effectively discriminate the resonant CARS signal from the nonresonant background owing to a phenomenon of molecular orientation in the sample medium. Such molecular orientation is intrinsically related to the induction of an electric dipole moment by the applied static electric field. Evidence of the electro-CARS effect is obtained with a solution of n -alkanes (CnH2 n +2 , 15 ≤n ≤40 ), for which an enhancement of the CARS signal-to-noise ratio is achieved in the case of CH2 and CH3 symmetric/asymmetric stretching vibrations. Additionally, an electric-field-induced second-harmonic generation experiment is performed in order to corroborate the orientational organization of molecules due to the electric field excitation. Finally, we use a simple mathematical approach to compare the vibrational information extracted from electro-CARS measurements with spontaneous Raman data and to highlight the impact of electric stimulation on the vibrational signal.

  1. Electrical Stimulation of Coleopteran Muscle for Initiating Flight.

    PubMed

    Choo, Hao Yu; Li, Yao; Cao, Feng; Sato, Hirotaka

    2016-01-01

    Some researchers have long been interested in reconstructing natural insects into steerable robots or vehicles. However, until recently, these so-called cyborg insects, biobots, or living machines existed only in science fiction. Owing to recent advances in nano/micro manufacturing, data processing, and anatomical and physiological biology, we can now stimulate living insects to induce user-desired motor actions and behaviors. To improve the practicality and applicability of airborne cyborg insects, a reliable and controllable flight initiation protocol is required. This study demonstrates an electrical stimulation protocol that initiates flight in a beetle (Mecynorrhina torquata, Coleoptera). A reliable stimulation protocol was determined by analyzing a pair of dorsal longitudinal muscles (DLMs), flight muscles that oscillate the wings. DLM stimulation has achieved with a high success rate (> 90%), rapid response time (< 1.0 s), and small variation (< 0.33 s; indicating little habituation). Notably, the stimulation of DLMs caused no crucial damage to the free flight ability. In contrast, stimulation of optic lobes, which was earlier demonstrated as a successful flight initiation protocol, destabilized the beetle in flight. Thus, DLM stimulation is a promising secure protocol for inducing flight in cyborg insects or biobots.

  2. Volume conductor model of transcutaneous electrical stimulation with kilohertz signals

    PubMed Central

    Medina, Leonel E.; Grill, Warren M.

    2014-01-01

    Objective Incorporating high-frequency components in transcutaneous electrical stimulation (TES) waveforms may make it possible to stimulate deeper nerve fibers since the impedance of tissue declines with increasing frequency. However, the mechanisms of high-frequency TES remain largely unexplored. We investigated the properties of TES with frequencies beyond those typically used in neural stimulation. Approach We implemented a multilayer volume conductor model including dispersion and capacitive effects, coupled to a cable model of a nerve fiber. We simulated voltage- and current-controlled transcutaneous stimulation, and quantified the effects of frequency on the distribution of potentials and fiber excitation. We also quantified the effects of a novel transdermal amplitude modulated signal (TAMS) consisting of a non-zero offset sinusoidal carrier modulated by a square-pulse train. Main results The model revealed that high-frequency signals generated larger potentials at depth than did low frequencies, but this did not translate into lower stimulation thresholds. Both TAMS and conventional rectangular pulses activated more superficial fibers in addition to the deeper, target fibers, and at no frequency did we observe an inversion of the strength-distance relationship. Current regulated stimulation was more strongly influenced by fiber depth, whereas voltage regulated stimulation was more strongly influenced by skin thickness. Finally, our model reproduced the threshold-frequency relationship of experimentally measured motor thresholds. Significance The model may be used for prediction of motor thresholds in TES, and contributes to the understanding of high-frequency TES. PMID:25380254

  3. Volume conductor model of transcutaneous electrical stimulation with kilohertz signals

    NASA Astrophysics Data System (ADS)

    Medina, Leonel E.; Grill, Warren M.

    2014-12-01

    Objective. Incorporating high-frequency components in transcutaneous electrical stimulation (TES) waveforms may make it possible to stimulate deeper nerve fibers since the impedance of tissue declines with increasing frequency. However, the mechanisms of high-frequency TES remain largely unexplored. We investigated the properties of TES with frequencies beyond those typically used in neural stimulation. Approach. We implemented a multilayer volume conductor model including dispersion and capacitive effects, coupled to a cable model of a nerve fiber. We simulated voltage- and current-controlled transcutaneous stimulation, and quantified the effects of frequency on the distribution of potentials and fiber excitation. We also quantified the effects of a novel transdermal amplitude modulated signal (TAMS) consisting of a non-zero offset sinusoidal carrier modulated by a square-pulse train. Main results. The model revealed that high-frequency signals generated larger potentials at depth than did low frequencies, but this did not translate into lower stimulation thresholds. Both TAMS and conventional rectangular pulses activated more superficial fibers in addition to the deeper, target fibers, and at no frequency did we observe an inversion of the strength-distance relationship. Current regulated stimulation was more strongly influenced by fiber depth, whereas voltage regulated stimulation was more strongly influenced by skin thickness. Finally, our model reproduced the threshold-frequency relationship of experimentally measured motor thresholds. Significance. The model may be used for prediction of motor thresholds in TES, and contributes to the understanding of high-frequency TES.

  4. Electrical Stimulation of Coleopteran Muscle for Initiating Flight

    PubMed Central

    Choo, Hao Yu; Li, Yao; Cao, Feng; Sato, Hirotaka

    2016-01-01

    Some researchers have long been interested in reconstructing natural insects into steerable robots or vehicles. However, until recently, these so-called cyborg insects, biobots, or living machines existed only in science fiction. Owing to recent advances in nano/micro manufacturing, data processing, and anatomical and physiological biology, we can now stimulate living insects to induce user-desired motor actions and behaviors. To improve the practicality and applicability of airborne cyborg insects, a reliable and controllable flight initiation protocol is required. This study demonstrates an electrical stimulation protocol that initiates flight in a beetle (Mecynorrhina torquata, Coleoptera). A reliable stimulation protocol was determined by analyzing a pair of dorsal longitudinal muscles (DLMs), flight muscles that oscillate the wings. DLM stimulation has achieved with a high success rate (> 90%), rapid response time (< 1.0 s), and small variation (< 0.33 s; indicating little habituation). Notably, the stimulation of DLMs caused no crucial damage to the free flight ability. In contrast, stimulation of optic lobes, which was earlier demonstrated as a successful flight initiation protocol, destabilized the beetle in flight. Thus, DLM stimulation is a promising secure protocol for inducing flight in cyborg insects or biobots. PMID:27050093

  5. Ownership of an artificial limb induced by electrical brain stimulation

    PubMed Central

    Collins, Kelly L.; Cronin, Jeneva; Olson, Jared D.; Ehrsson, H. Henrik; Ojemann, Jeffrey G.

    2017-01-01

    Replacing the function of a missing or paralyzed limb with a prosthetic device that acts and feels like one’s own limb is a major goal in applied neuroscience. Recent studies in nonhuman primates have shown that motor control and sensory feedback can be achieved by connecting sensors in a robotic arm to electrodes implanted in the brain. However, it remains unknown whether electrical brain stimulation can be used to create a sense of ownership of an artificial limb. In this study on two human subjects, we show that ownership of an artificial hand can be induced via the electrical stimulation of the hand section of the somatosensory (SI) cortex in synchrony with touches applied to a rubber hand. Importantly, the illusion was not elicited when the electrical stimulation was delivered asynchronously or to a portion of the SI cortex representing a body part other than the hand, suggesting that multisensory integration according to basic spatial and temporal congruence rules is the underlying mechanism of the illusion. These findings show that the brain is capable of integrating “natural” visual input and direct cortical-somatosensory stimulation to create the multisensory perception that an artificial limb belongs to one’s own body. Thus, they serve as a proof of concept that electrical brain stimulation can be used to “bypass” the peripheral nervous system to induce multisensory illusions and ownership of artificial body parts, which has important implications for patients who lack peripheral sensory input due to spinal cord or nerve lesions. PMID:27994147

  6. Neural responses to electrical stimulation on patterned silk films.

    PubMed

    Hronik-Tupaj, Marie; Raja, Waseem Khan; Tang-Schomer, Min; Omenetto, Fiorenzo G; Kaplan, David L

    2013-09-01

    Peripheral nerve injury is a critical issue for patients with trauma. Following injury, incomplete axon regeneration or misguided axon innervation into tissue will result in loss of sensory and motor functions. The objective of this study was to examine axon outgrowth and axon alignment in response to surface patterning and electrical stimulation. To accomplish our objective, metal electrodes with dimensions of 1.5 mm × 4 cm, were sputter coated onto micropatterned silk protein films, with surface grooves 3.5 μm wide × 500 nm deep. P19 neurons were seeded on the patterned electronic silk films and stimulated at 120 mV, 1 kHz, for 45 min each day for 7 days. Responses were compared with neurons on flat electronic silk films, patterned silk films without stimulation, and flat silk films without stimulation. Significant alignment was found on the patterned film groups compared with the flat film groups. Axon outgrowth was greater (p < 0.05) on electronic films on days 5 and 7 compared with the unstimulated groups. In conclusion, electrical stimulation, at 120 mV, 1 kHz, for 45 min daily, in addition to surface patterning, of 3.5 μm wide × 500 nm deep grooves, offered control of nerve axon outgrowth and alignment.

  7. The action of knee joint afferents and the concomitant influence of cutaneous (sural) afferents on the discharge of triceps surae gamma-motoneurones in the cat.

    PubMed

    Ellaway, P H; Davey, N J; Ferrell, W R; Baxendale, R H

    1996-01-01

    Electrical stimulation of group II joint afferents of the posterior articular nerve (PAN) to the knee evoked short-latency facilitation and/or inhibition of the background discharge of gastrocnemius-soleus (GS) gamma-motoneurones in decerebrated spinal cats. The latencies of these responses were consistent with mediation via segmental oligosynaptic spinal pathways. In addition, a longer-latency facilitation was frequently observed. Mechanical non-noxious stimulation of the skin within the field of innervation of the sural nerve, on the lateral aspect of the heel, suppressed the short-latency facilitation, but not the inhibition or long-latency facilitation. Brief mechanical indentation of the posterior aspect of the knee joint capsule could elicit facilitation or inhibition of gamma-motoneurones. Facilitation, but not inhibition, was blocked by anaesthesia or section of the PAN. Both actions could be suppressed by mechanical stimulation of the heel. We conclude that GS gamma-motoneurones receive both facilitatory and inhibitory segmental inputs from group II articular afferents arising in the knee joint. Cutaneous afferents from the sural field exert a selective inhibitory influence over the facilitation of fusimotor discharge by articular afferents.

  8. Efficacy of Transcutaneous Electrical Nerve Stimulation in the Treatment of Overactive Bladder

    PubMed Central

    Rekha, Kaja; Srinivasan, Krishnamurthy Jayashree

    2016-01-01

    Introduction Overactive Bladder (OAB) accounts for 40-70% cases of incontinence. The etiology is unknown though detrusor instability is found in urodynamic evaluation of almost all cases. Detrusor instability or hyperreflexia can be inhibited by direct inhibition of impulses in the pre-ganglionic afferent neuron or by inhibition of bladder pre-ganglionic neurons of the efferent limb of micturition reflex. Transcutaneous Electrical Nerve Stimulation (TENS) is based on the gate control theory of abolishing the local micturition reflex arc. Aim To assess the effectiveness and safety of TENS in idiopathic OAB. Materials and Methods It is a prospective experimental study to evaluate the effectiveness of TENS v/s placebo in reducing OAB symptoms. (n1=20, n2 =20). Ten treatment sessions (5 sessions/week) of 30 minutes, were conducted. Results There was a significant improvement in Overactive Bladder Symptom Scores (OABSS) in TENS group and 2 patients were completely dry following TENS therapy. Conclusion In elderly women, patients with OAB where other co-medications have their own anticholinergic side effects and impairment of cognition is a concern, TENS can be a useful intervention. TENS units are safe, economical and easily commercially available. PMID:27891403

  9. Determinants of the electric field during transcranial direct current stimulation.

    PubMed

    Opitz, Alexander; Paulus, Walter; Will, Susanne; Antunes, Andre; Thielscher, Axel

    2015-04-01

    Transcranial direct current stimulation (tDCS) causes a complex spatial distribution of the electric current flow in the head which hampers the accurate localization of the stimulated brain areas. In this study we show how various anatomical features systematically shape the electric field distribution in the brain during tDCS. We constructed anatomically realistic finite element (FEM) models of two individual heads including conductivity anisotropy and different skull layers. We simulated a widely employed electrode montage to induce motor cortex plasticity and moved the stimulating electrode over the motor cortex in small steps to examine the resulting changes of the electric field distribution in the underlying cortex. We examined the effect of skull thickness and composition on the passing currents showing that thinner skull regions lead to higher electric field strengths. This effect is counteracted by a larger proportion of higher conducting spongy bone in thicker regions leading to a more homogenous current over the skull. Using a multiple regression model we could identify key factors that determine the field distribution to a significant extent, namely the thicknesses of the cerebrospinal fluid and the skull, the gyral depth and the distance to the anode and cathode. These factors account for up to 50% of the spatial variation of the electric field strength. Further, we demonstrate that individual anatomical factors can lead to stimulation "hotspots" which are partly resistant to electrode positioning. Our results give valuable novel insights in the biophysical foundation of tDCS and highlight the importance to account for individual anatomical factors when choosing an electrode montage.

  10. Modulation of ankle EMG in spinally contused rats through application of neuromuscular electrical stimulation timed to robotic treadmill training.

    PubMed

    Askari, Sina; Kamgar, Parisa; Chao, TeKang; Diaz, Eric; de Leon, Ray D; Won, Deborah S

    2012-01-01

    While neuromuscular electrical stimulation (NMES) has enabled patients of neuromotor dysfunction to effectively regain some functions, analysis of neuromuscular changes underlying these functional improvements is lacking. We have developed an NMES system for a rodent model of SCI with the long term goal of creating a therapy which restores control over stepping back to the spinal circuitry. NMES was applied to the tibialis anterior (TA) and timed to the afferent feedback generated during robotic treadmill training (RTT). The effect of NMES+RTT on modifications in EMG was compared with that of RTT alone. A longitudinal study with a crossover design was conducted in which group 1 (n=7) received 2 weeks of RTT only followed by 2 weeks of NMES+RTT; group 2 (n=7) received 2 weeks of NMES+RTT followed by RTT only. On average, both types of training helped to modulate TA EMG activity over a gait cycle, resulting in EMG profiles across steps with peaks occurring just before or at the beginning of the swing phase, when ankle flexion is most needed. However, NMES+RTT resulted in concentration of EMG activation during the initial swing phase more than RTT only. In conjunction with these improvements in EMG activation presented here, a more complete analyses comparing changes after NMES+RTT vs. RTT is expected to further support the notion that NMES timed appropriately to hindlimb stepping could help to reinforce the motor learning that is induced by afferent activity generated by treadmill training.

  11. Measurements and models of electric fields in the in vivo human brain during transcranial electric stimulation.

    PubMed

    Huang, Yu; Liu, Anli A; Lafon, Belen; Friedman, Daniel; Dayan, Michael; Wang, Xiuyuan; Bikson, Marom; Doyle, Werner K; Devinsky, Orrin; Parra, Lucas C

    2017-02-07

    Transcranial electric stimulation aims to stimulate the brain by applying weak electrical currents at the scalp. However, the magnitude and spatial distribution of electric fields in the human brain are unknown. We measured electric potentials intracranially in ten epilepsy patients and estimate electric fields across the entire brain by leveraging calibrated current-flow models. When stimulating at 2 mA, cortical electric fields reach 0.4 V/m, the lower limit of effectiveness in animal studies. When individual whole-head anatomy is considered, the predicted electric field magnitudes correlate with the recorded values in cortical (r=0.89) and depth (r=0.84) electrodes. Accurate models require adjustment of tissue conductivity values reported in the literature, but accuracy is not improved when incorporating white matter anisotropy or different skull compartments. This is the first study to validate and calibrate current-flow models with in vivo intracranial recordings in humans, providing a solid foundation to target stimulation and interpret clinical trials.

  12. Measurements and models of electric fields in the in vivo human brain during transcranial electric stimulation

    PubMed Central

    Huang, Yu; Liu, Anli A; Lafon, Belen; Friedman, Daniel; Dayan, Michael; Wang, Xiuyuan; Bikson, Marom; Doyle, Werner K; Devinsky, Orrin; Parra, Lucas C

    2017-01-01

    Transcranial electric stimulation aims to stimulate the brain by applying weak electrical currents at the scalp. However, the magnitude and spatial distribution of electric fields in the human brain are unknown. We measured electric potentials intracranially in ten epilepsy patients and estimated electric fields across the entire brain by leveraging calibrated current-flow models. When stimulating at 2 mA, cortical electric fields reach 0.4 V/m, the lower limit of effectiveness in animal studies. When individual whole-head anatomy is considered, the predicted electric field magnitudes correlate with the recorded values in cortical (r = 0.89) and depth (r = 0.84) electrodes. Accurate models require adjustment of tissue conductivity values reported in the literature, but accuracy is not improved when incorporating white matter anisotropy or different skull compartments. This is the first study to validate and calibrate current-flow models with in vivo intracranial recordings in humans, providing a solid foundation to target stimulation and interpret clinical trials. DOI: http://dx.doi.org/10.7554/eLife.18834.001 PMID:28169833

  13. Analysis of electric field stimulation of single cardiac muscle cells.

    PubMed Central

    Tung, L; Borderies, J R

    1992-01-01

    Electrical stimulation of cardiac cells by imposed extracellular electric fields results in a transmembrane potential which is highly nonuniform, with one end of the cell depolarized and the other end hyperpolarized along the field direction. To date, the implications of the close proximity of oppositely polarized membranes on excitability have not been explored. In this work we compare the biophysical basis for field stimulation of cells at rest with that for intracellular current injection, using three Luo-Rudy type membrane patches coupled together as a lumped model to represent the cell membrane. Our model shows that cell excitation is a function of the temporal and spatial distribution of ionic currents and transmembrane potential. The extracellular and intracellular forms of stimulation were compared in greater detail for monophasic and symmetric biphasic rectangular pulses, with duration ranging from 0.5 to 10 ms. Strength-duration curves derived for field stimulation show that over a wide range of pulse durations, biphasic waveforms can recruit and activate membrane patches about as effectively as can monophasic waveforms having the same total pulse duration. We find that excitation with biphasic stimulation results from a synergistic, temporal summation of inward currents through the sodium channel in membrane patches at opposite ends of the cell. Furthermore, with both waveform types, a net inward current through the inwardly rectifying potassium channel contributes to initial membrane depolarization. In contrast, models of stimulation by intracellular current injection do not account for the nonuniformity of transmembrane potential and produce substantially different (even contradictory) results for the case of stimulation from rest. PMID:1420884

  14. Spinal projection of spindle afferents of the longissimus lumborum muscles of the cat.

    PubMed

    Durbaba, R; Taylor, A; Ellaway, P H; Rawlinson, S

    2007-04-15

    The connections and monosynaptic projections of muscle spindle afferents of individual heads of the longissimus lumborum have been studied in cats by natural stimulation, by electrical stimulation and by spike-triggered averaging from single identified afferents. The spindle afferents were classified by sensitivity to vibration and by the effect of succinylcholine on their response to ramp-and-hold muscle stretches. Axonal conduction and synaptic effects were recorded as field potentials and focal synaptic potentials during systematic exploration of the spinal cord in segments L1 to L4 with extracellular metal microelectrodes, singly and in linear arrays. Ascending branches of afferent axons within the cord had a significantly higher mean conduction velocity (CV: 56.5 m s(-1)) than descending branches (40.8 m s(-1)). The CV of ascending branches was significantly positively correlated with a measure of the strength of intrafusal bag(2) muscle fibre contacts, but not to a measure of bag(1) contacts. Two sites of monosynaptic excitatory projection in the cord were identified, namely to the intermediate region (laminae V, VI and VII) and to ventral horn region (laminae VIII and IX). In tests of 154 single afferents, signs of central projection were detected for 60, providing 122 regions of maximum negative focal synaptic potentials (FSPs) of mean amplitude 7.51 microV. Their longitudinal spacing indicated that axons gave off descending collaterals at intervals of 1.5-3.5 mm. Based on the amplitude of FSPs, the projection of secondary afferents is stronger than that of primaries in the intermediate region and possibly also in the ventral horn region. Evidence is also presented that spindle afferent input from different heads of the longissimus converges into any given spinal segment and that input in one spinal root projects to adjacent segments. It is concluded that the organization of the longissimus monosynaptic spindle input favours relatively tonic and diffuse

  15. Characterization of electrical stimulation electrodes for cardiac tissue engineering.

    PubMed

    Tandon, Nina; Cannizzaro, Chris; Figallo, Elisa; Voldman, Joel; Vunjak-Novakovic, Gordana

    2006-01-01

    Electrical stimulation has been shown to improve functional assembly of cardiomyocytes in vitro for cardiac tissue engineering. The goal of this study was to assess the conditions of electrical stimulation with respect to the electrode geometry, material properties and charge-transfer characteristics at the electrode-electrolyte interface. We compared various biocompatible materials, including nanoporous carbon, stainless steel, titanium and titanium nitride, for use in cardiac tissue engineering bioreactors. The faradaic and non-faradaic charge transfer mechanisms were assessed by electrochemical impedance spectroscopy (EIS), studying current injection characteristics, and examining surface properties of electrodes with scanning electron microscopy. Carbon electrodes were found to have the best current injection characteristics. However, these electrodes require careful handling because of their limited mechanical strength. The efficacy of various electrodes for use in 2-D and 3-D cardiac tissue engineering systems with neonatal rat cardiomyocytes is being determined by assessing cell viability, amplitude of contractions, excitation thresholds, maximum capture rate, and tissue morphology.

  16. Neuromuscular Electrical Stimulation for Mobility Support of Elderly

    PubMed Central

    2015-01-01

    The stimulator for neuromuscular electrical stimulation for mobility support of elderly is not very complicated, but for application within “MOBIL” we have some additional demands to fulfill. First we have specific safety issues for this user group. A powerful compliance management system is crucial not only to guide daily application, but for creating hard data for the scientific outcome. We also need to assure easy handling of the stimulator, because the subjects are generally not able to cope with too difficult and complex motor skills. So, we developed five generations of stimulators and optimizing solutions after field tests. We are already planning the sixth generation with wireless control of the stimulation units by the central main handheld control unit. In a prototype, we have implemented a newly available high capacity memory, a breakthrough in “compliance data storage” as they offer the necessary high storage capacity and fast data handling for an affordable prize. The circuit also contains a 3D accelerometer sensor which acts as a further important safety features: if the control unit drops, this event is detected automatically by the sensor and activates an emergency switch-off that disables the stimulation to avoid associated risks. Further, we have implemented a hardware emergence shutdown and other safety measures. Finally, in the last example muscle torque measurements are referenced with compliance data. In the study normalized maximum voluntary contraction (MVC) and maximum stimulation induced contraction (MSC) were assessed in regular check-ups along the training period. With additional consideration of adjusted stimulation intensity for training out of the compliance data records we are able to estimate the induced contraction strength, which turned out to amount in average 11% of MVC. This value may seem on a first sight rather low, and ought to be considered in relation to the results at the end of the training period. Therefore the

  17. Effects of chronic electrical stimulation on paralyzed expiratory muscles

    PubMed Central

    DiMarco, Anthony F.; Kowalski, Krzysztof E.

    2013-01-01

    Following spinal cord injury, the expiratory muscles develop significant disuse atrophy characterized by reductions in their weight, fiber cross-sectional area, and force-generating capacity. We determined the extent to which these physiological alterations can be prevented with electrical stimulation. Because a critical function of the expiratory muscles is cough generation, an important goal was the maintenance of maximal force production. In a cat model of spinal cord injury, short periods of high-frequency lower thoracic electrical spinal cord stimulation (SCS) at the T10 level (50 Hz, 15 min, twice/day, 5 days/wk) were initiated 2 wk following spinalization and continued for a 6-mo period. Airway pressure (P)-generating capacity was determined by SCS. Five acute, spinalized animals served as controls. Compared with controls, initial P fell from 43.9 ± 1.0 to 41.8 ± 0.7 cmH2O (not significant) in the chronic animals. There were small reductions in the weight of the external oblique, internal oblique, transverses abdominis, internal intercostal, and rectus abdominis muscles (not significant for each). There were no significant changes in the population of fast muscle fibers. Because prior studies (Kowalski KE, Romaniuk JR, DiMarco AF. J Appl Physiol 102: 1422-1428, 2007) have demonstrated significant atrophy following spinalization in this model, these results indicate that expiratory muscle atrophy can be prevented by the application of short periods of daily high-frequency stimulation. Because the frequency of stimulation is similar to the expected pattern of clinical use for cough generation, the daily application of electrical stimulation could potentially serve the dual purpose of maintenance of expiratory muscle function and airway clearance. PMID:18403449

  18. Clinical application of neuromuscular electrical stimulation induced cardiovascular exercise.

    PubMed

    Caulfield, Brian; Crowe, Louis; Coughlan, Garrett; Minogue, Conor

    2011-01-01

    We need to find novel ways of increasing exercise participation, particularly in those populations who find it difficult to participate in voluntary exercise. In recent years researchers have started to investigate the potential for using electrical stimulation to artificially stimulate a pattern of muscle activity that would induce a physiological response consistent with cardiovascular exercise. Work to date has indicated that this is best achieved by using a stimulation protocol that results in rapid rhythmical isometric contractions of the large leg muscle groups at sub tetanic frequencies. Studies completed by our group indicate that this technique can serve as a viable alternative to voluntary cardiovascular exercise. Apart from being able to induce a cardiovascular exercise effect in patient populations (e.g. heart failure, COPD, spinal cord injury, obesity), this approach may also have value in promotion of exercise activity in a microgravity environment.

  19. Spatially distributed sequential stimulation reduces muscle fatigue during neuromuscular electrical stimulation.

    PubMed

    Sayenko, Dimitry G; Popovic, Milos R; Masani, Kei

    2013-01-01

    A critical limitation with neuromuscular electrical stimulation (NMES) approach is the rapid onset of muscle fatigue during repeated contractions, which results in the muscle force decay and slowing of muscle contractile properties. In our previous study, we demonstrated that spatially distributed sequential stimulation (SDSS) show a drastically greater fatigue-reducing ability compared to a conventional, single active electrode stimulation (SES) with an individual with spinal cord injury when applied for plantar flexors. The purpose of the present study is to explore the fatigue-reducing ability of SDSS for major lower limb muscle groups in the able-bodied population as well as individuals with spinal cord injury (SCI). SDSS was delivered through four active electrodes applied to the muscle of interest, sending a stimulation pulse to each electrode one after another with 90° phase shift between successive electrodes. For comparison, SES was delivered through one active electrode. For both modes of stimulation, the resultant frequency to the muscle as a whole was 40 Hz. Using corresponding protocols for the fatiguing stimulation, we demonstrated the fatigue-reducing ability of SDSS by higher fatigue indices as compared with single active electrode setup for major leg muscles in both subject groups. The present work verifies and extends reported findings on the effectiveness of using spatially distributed sequential stimulation in the leg muscles to reduce muscle fatigue. Application of this technique can improve the usefulness of NMES during functional movements in the clinical setup.

  20. Practical aspects of cardiac tissue engineering with electrical stimulation.

    PubMed

    Cannizzaro, Christopher; Tandon, Nina; Figallo, Elisa; Park, Hyoungshin; Gerecht, Sharon; Radisic, Milica; Elvassore, Nicola; Vunjak-Novakovic, Gordana

    2007-01-01

    Heart disease is a leading cause of death in western society. Despite the success of heart transplantation, a chronic shortage of donor organs, along with the associated immunological complications of this approach, demands that alternative treatments be found. One such option is to repair, rather than replace, the heart with engineered cardiac tissue. Multiple studies have shown that to attain functional tissue, assembly signaling cues must be recapitulated in vitro. In their native environment, cardiomyocytes are directed to beat in synchrony by propagation of pacing current through the tissue. Recently, we have shown that electrical stimulation directs neonatal cardiomyocytes to assemble into native-like tissue in vitro. This chapter provides detailed methods we have employed in taking this "biomimetic" approach. After an initial discussion on how electric field stimulation can influence cell behavior, we examine the practical aspects of cardiac tissue engineering with electrical stimulation, such as electrode selection and cell seeding protocols, and conclude with what we feel are the remaining challenges to be overcome.

  1. Neuromuscular electric stimulation in patellofemoral dysfunction: literature review

    PubMed Central

    dos Santos, Ricardo Lucas; Souza, Márcia Leal São Pedro; dos Santos, Fernanda Andrade

    2013-01-01

    Patellofemoral dysfunction is a fairly common deficiency among young individuals that primarily affects females and may be characterized by pain, swelling and retropatellar crepitation. The purpose of this review of literature from the period between 2005 and 2011 was to systematize knowledge in relation to the increase in quadriceps muscle strength and pain relief in patients with patellofemoral dysfunction, using neuromuscular electrical stimulation and resistance exercises. The inclusion criteria were intervention articles from the past six years, in English, Spanish and Portuguese, which used muscle strengthening and neuromuscular electrical stimulation for rehabilitation obtained through searches in the electronic databases Medline and Lilacs and in the Bireme library. The bibliographic search yielded 28 references, of which nine were excluded in accordance with the aims and inclusion criteria while 16 articles were selected for reading of the abstracts and subsequent analysis. Mediumfrequency Neuromuscular Electrical Stimulation (NMES) can be used in association with resistance exercises as an adjuvant in the treatment of patellofemoral dysfunction (PFD), both to achieve muscle rebalance and for pain relief. PMID:24453645

  2. Self-Triggered Functional Electrical Stimulation During Swallowing

    PubMed Central

    Burnett, Theresa A.; Mann, Eric A.; Stoklosa, Joseph B.; Ludlow, Christy L.

    2006-01-01

    Hyolaryngeal elevation is essential for airway protection during swallowing and is mainly a reflexive response to oropharyngeal sensory stimulation. Targeted intramuscular electrical stimulation can elevate the resting larynx and, if applied during swallowing, may improve airway protection in dysphagic patients with inadequate hyolaryngeal motion. To be beneficial, patients must synchronize functional electrical stimulation (FES) with their reflexive swallowing and not adapt to FES by reducing the amplitude or duration of their own muscle activity. We evaluated the ability of nine healthy adults to manually synchronize FES with hyolaryngeal muscle activity during discrete swallows, and tested for motor adaptation. Hooked-wire electrodes were placed into the mylo- and thyrohyoid muscles to record electromyographic activity from one side of the neck and deliver monopolar FES for hyolaryngeal elevation to the other side. After performing baseline swallows, volunteers were instructed to trigger FES with a thumb switch in synchrony with their swallows for a series of trials. An experimenter surreptitiously disabled the thumb switch during the final attempt, creating a foil. From the outset, volunteers synchronized FES with the onset of swallow-related thyrohyoid activity (~225 ms after mylohyoid activity onset), preserving the normal sequence of muscle activation. A comparison between average baseline and foil swallows failed to show significant adaptive changes in the amplitude, duration, or relative timing of activity for either muscle, indicating that the central pattern generator for hyolaryngeal elevation is immutable with short term stimulation that augments laryngeal elevation during the reflexive, pharyngeal phase of swallowing. PMID:16107520

  3. New algorithm to control a cycle ergometer using electrical stimulation.

    PubMed

    Petrofsky, J S

    2003-01-01

    Data were collected from four male subjects to determine the relationships between load, speed and muscle use during cycle ergometry. These data were then used to construct equations to govern the stimulation of muscle in paralysed individuals, during cycle ergometry induced by functional electrical stimulation (FES) of the quadriceps, gluteus maximus and hamstring muscles. The algorithm was tested on four subjects who were paralysed owing to a complete spinal cord injury between T4 and T11. Using the multivariate equation, the control of movement was improved, and work was accomplished that was double (2940 Nm min(-1) compared with 5880 Nm min(-1)) that of traditional FES cycle ergometry, when muscle stimulation was also controlled by electrical stimulation. Stress on the body, assessed by cardiac output, was increased almost two-fold during maximum work with the new algorithm (81 min(-1) compared with 15 l min(-1) with the new algorithm). These data support the concept that the limitation to workload that a person can achieve on FES cycle ergometry is in the control equations and not in the paralysed muscle.

  4. Stimulation of Neurite Outgrowth Using an Electrically Conducting Polymer

    NASA Astrophysics Data System (ADS)

    Schmidt, Christine E.; Shastri, Venkatram R.; Vacanti, Joseph P.; Langer, Robert

    1997-08-01

    Damage to peripheral nerves often cannot be repaired by the juxtaposition of the severed nerve ends. Surgeons have typically used autologous nerve grafts, which have several drawbacks including the need for multiple surgical procedures and loss of function at the donor site. As an alternative, the use of nerve guidance channels to bridge the gap between severed nerve ends is being explored. In this paper, the electrically conductive polymer--oxidized polypyrrole (PP)--has been evaluated for use as a substrate to enhance nerve cell interactions in culture as a first step toward potentially using such polymers to stimulate in vivo nerve regeneration. Image analysis demonstrates that PC-12 cells and primary chicken sciatic nerve explants attached and extended neurites equally well on both PP films and tissue culture polystyrene in the absence of electrical stimulation. In contrast, PC-12 cells interacted poorly with indium tin oxide (ITO), poly(L-lactic acid) (PLA), and poly(lactic acid-coglycolic acid) surfaces. However, PC-12 cells cultured on PP films and subjected to an electrical stimulus through the film showed a significant increase in neurite lengths compared with ones that were not subjected to electrical stimulation through the film and tissue culture polystyrene controls. The median neurite length for PC-12 cells grown on PP and subjected to an electrical stimulus was 18.14 μ m (n = 5643) compared with 9.5 μ m (n = 4440) for controls. Furthermore, animal implantation studies reveal that PP invokes little adverse tissue response compared with poly(lactic acid-coglycolic acid).

  5. Stimulation of neurite outgrowth using an electrically conducting polymer

    PubMed Central

    Schmidt, Christine E.; Shastri, Venkatram R.; Vacanti, Joseph P.; Langer, Robert

    1997-01-01

    Damage to peripheral nerves often cannot be repaired by the juxtaposition of the severed nerve ends. Surgeons have typically used autologous nerve grafts, which have several drawbacks including the need for multiple surgical procedures and loss of function at the donor site. As an alternative, the use of nerve guidance channels to bridge the gap between severed nerve ends is being explored. In this paper, the electrically conductive polymer—oxidized polypyrrole (PP)—has been evaluated for use as a substrate to enhance nerve cell interactions in culture as a first step toward potentially using such polymers to stimulate in vivo nerve regeneration. Image analysis demonstrates that PC-12 cells and primary chicken sciatic nerve explants attached and extended neurites equally well on both PP films and tissue culture polystyrene in the absence of electrical stimulation. In contrast, PC-12 cells interacted poorly with indium tin oxide (ITO), poly(l-lactic acid) (PLA), and poly(lactic acid-co-glycolic acid) surfaces. However, PC-12 cells cultured on PP films and subjected to an electrical stimulus through the film showed a significant increase in neurite lengths compared with ones that were not subjected to electrical stimulation through the film and tissue culture polystyrene controls. The median neurite length for PC-12 cells grown on PP and subjected to an electrical stimulus was 18.14 μm (n = 5643) compared with 9.5 μm (n = 4440) for controls. Furthermore, animal implantation studies reveal that PP invokes little adverse tissue response compared with poly(lactic acid-co-glycolic acid). PMID:9256415

  6. [Research progress in reanimation of peripheral facial paralysis by use of functional electrical stimulation].

    PubMed

    Deng, Simin; Shen, Guofang

    2010-08-01

    With the development of electronics and information technology, the application of functional electrical stimulation in the medical field has been expanding. However, the use of functional electrical stimulation to treat patients with peripheral facial paralysis is still in its infancy. The main problems include: (1) Finding in the signals which could fire the stimulator; (2) Exploring the parameters for the stimulator; (3) The effects on the muscle attributed to the electrical stimulation. A review on these problems is presented.

  7. Effect of neuromuscular electrical stimulation on motor cortex excitability upon release of tonic muscle contraction.

    PubMed

    Sugawara, Kenichi; Tanabe, Shigeo; Suzuki, Tomotaka; Higashi, Toshio

    The aim of the present study was to investigate the neurophysiological triggers underlying muscle relaxation from the contracted state, and to examine the mechanisms involved in this process and their subsequent modification by neuromuscular electrical stimulation (NMES). Single-pulse transcranial magnetic stimulation (TMS) was used to produce motor-evoked potentials (MEPs) and short-interval intracortical inhibition (SICI) in 23 healthy participants, wherein motor cortex excitability was examined at the onset of voluntary muscle relaxation following a period of voluntary tonic muscle contraction. In addition, the effects of afferent input on motor cortex excitability, as produced by NMES during muscle contraction, were examined. In particular, two NMES intensities were used for analysis: 1.2 times the sensory threshold and 1.2 times the motor threshold (MT). Participants were directed to execute constant wrist extensions and to release muscle contraction in response to an auditory "GO" signal. MEPs were recorded from the flexor carpi radialis (FCR) and extensor carpi radialis (ECR) muscles, and TMS was applied at three different time intervals (30, 60, and 90 ms) after the "GO" signal. Motor cortex excitability was greater during voluntary ECR and FCR relaxation using high-intensity NMES, and relaxation time was decreased. Each parameter differed significantly between 30 and 60 ms. Moreover, in both muscles, SICI was larger in the presence than in the absence of NMES. Therefore, the present findings suggest that terminating a muscle contraction triggers transient neurophysiological mechanisms that facilitate the NMES-induced modulation of cortical motor excitability in the period prior to muscle relaxation. High-intensity NMES might facilitate motor cortical excitability as a function of increased inhibitory intracortical activity, and therefore serve as a transient trigger for the relaxation of prime mover muscles in a therapeutic context.

  8. Morphologically mixed chemical-electrical synapses formed by primary afferents in rodent vestibular nuclei as revealed by immunofluorescence detection of connexin36 and vesicular glutamate transporter-1

    PubMed Central

    Nagy, James I.; Bautista, Wendy; Blakley, Brian; Rash, John E.

    2013-01-01

    Axon terminals forming mixed chemical/electrical synapses in the lateral vestibular nucleus of rat were described over forty years ago. Because gap junctions formed by connexins are the morphological correlate of electrical synapses, and with demonstrations of widespread expression of the gap junction protein connexin36 (Cx36) in neurons, we investigated the distribution and cellular localization of electrical synapses in the adult and developing rodent vestibular nuclear complex, using immunofluorescence detection of Cx36 as a marker for these synapses. In addition, we examined Cx36 localization in relation to that of the nerve terminal marker vesicular glutamate transporter-1 (vglut-1). An abundance of immunolabelling for Cx36 in the form of Cx36-puncta was found in each of the four major vestibular nuclei of adult rat and mouse. Immunolabelling was associated with somata and initial dendrites of medium and large neurons, and was absent in vestibular nuclei of Cx36 knockout mice. Cx36-puncta were seen either dispersed or aggregated into clusters on the surface of neurons, and were never found to occur intracellularly. Nearly all Cx36-puncta were localized to large nerve terminals immunolabelled for vglut-1. These terminals and their associated Cx36-puncta were substantially depleted after labyrinthectomy. Developmentally, labelling for Cx36 was already present in the vestibular nuclei at postnatal day 5, where it was only partially co-localized with vglut-1, and did not become fully associated with vglut-1-positive terminals until postnatal day 20 to 25. The results show that vglut-1-positive primary afferent nerve terminals form mixed synapses throughout the vestibular nuclear complex, that the gap junction component of these synapses contain Cx36, that multiple Cx36-containing gap junctions are associated with individual vglut-1 terminals and that the development of these mixed synapses is protracted over several postnatal weeks. PMID:23912039

  9. Morphologically mixed chemical-electrical synapses formed by primary afferents in rodent vestibular nuclei as revealed by immunofluorescence detection of connexin36 and vesicular glutamate transporter-1.

    PubMed

    Nagy, J I; Bautista, W; Blakley, B; Rash, J E

    2013-11-12

    Axon terminals forming mixed chemical/electrical synapses in the lateral vestibular nucleus of rat were described over 40 years ago. Because gap junctions formed by connexins are the morphological correlate of electrical synapses, and with demonstrations of widespread expression of the gap junction protein connexin36 (Cx36) in neurons, we investigated the distribution and cellular localization of electrical synapses in the adult and developing rodent vestibular nuclear complex, using immunofluorescence detection of Cx36 as a marker for these synapses. In addition, we examined Cx36 localization in relation to that of the nerve terminal marker vesicular glutamate transporter-1 (vglut-1). An abundance of immunolabeling for Cx36 in the form of Cx36-puncta was found in each of the four major vestibular nuclei of adult rat and mouse. Immunolabeling was associated with somata and initial dendrites of medium and large neurons, and was absent in vestibular nuclei of Cx36 knockout mice. Cx36-puncta were seen either dispersed or aggregated into clusters on the surface of neurons, and were never found to occur intracellularly. Nearly all Cx36-puncta were localized to large nerve terminals immunolabeled for vglut-1. These terminals and their associated Cx36-puncta were substantially depleted after labyrinthectomy. Developmentally, labeling for Cx36 was already present in the vestibular nuclei at postnatal day 5, where it was only partially co-localized with vglut-1, and did not become fully associated with vglut-1-positive terminals until postnatal day 20-25. The results show that vglut-1-positive primary afferent nerve terminals form mixed synapses throughout the vestibular nuclear complex, that the gap junction component of these synapses contains Cx36, that multiple Cx36-containing gap junctions are associated with individual vglut-1 terminals and that the development of these mixed synapses is protracted over several postnatal weeks.

  10. Giovanni Aldini: from animal electricity to human brain stimulation.

    PubMed

    Parent, André

    2004-11-01

    Two hundred years ago, Giovanni Aldini published a highly influential book that reported experiments in which the principles of Luigi Galvani (animal electricity) and Alessandro Volta (bimetallic electricity) were used together for the first time. Aldini was born in Bologna in 1762 and graduated in physics at the University of his native town in 1782. As nephew and assistant of Galvani, he actively participated in a series of crucial experiments with frog's muscles that led to the idea that electricity was the long-sought vital force coursing from brain to muscles. Aldini became professor of experimental physics at the University of Bologna in 1798. He traveled extensively throughout Europe, spending much time defending the concept of his discreet uncle against the incessant attacks of Volta, who did not believe in animal electricity. Aldini used Volta's bimetallic pile to apply electric current to dismembered bodies of animals and humans; these spectacular galvanic reanimation experiments made a strong and enduring impression on his contemporaries. Aldini also treated patients with personality disorders and reported complete rehabilitation following transcranial administration of electric current. Aldini's work laid the ground for the development of various forms of electrotherapy that were heavily used later in the 19th century. Even today, deep brain stimulation, a procedure currently employed to relieve patients with motor or behavioral disorders, owes much to Aldini and galvanism. In recognition of his merits, Aldini was made a knight of the Iron Crown and a councillor of state at Milan, where he died in 1834.

  11. Topographical effects of transcutaneous electrical nerve stimulation on the H-reflex of the triceps surae muscles.

    PubMed

    Goulet, C; Arsenault, A B; Bourbonnais, D; Levin, M F

    1994-01-01

    The present study was conducted on eight normal subjects in order to evaluate the effects of transcutaneous electrical nerve stimulation (TENS); 99 Hz, 250 μs pulse duration, applied over either the common peroneal (CPN) or sural nerve, on the H-reflex of the soleus (SO), gastrocnemius medialis (GM) and gastrocnemius lateralis (GL) muscles. Within each session, SO, GL and GM H-reflexes were recorded before (for 5 min), during (for 30 min) and after (for 10 min) TENS was applied at twice the sensory threshold for perception. It was found that, on average, while the stimulation was administered on the CPN: (a) the GL H-reflex amplitude increased by 40% (Friedman test: χ(2) = 11.71, P < 0.05); (b) the SO H-reflex decreased (≥ 10% H(ctrl)), although not in a statistically significant manner, in five of eight subjects; and (c) the GM H-reflex remained, overall, relatively stable. No significant effects of TENS over the sural nerve were found on any of the investigated muscles. The finding of increased H-reflex amplitudes in GL during TENS made it less likely that CPN stimulation had reciprocal inhibitory effects. However, such an increase could be attributed to a selective effect (such as a decrease in the recruitment threshold) on type II motoneurons of the GL. Furthermore, the topographical effects observed on the GL during TENS may reflect selective local effects due to stimulation of a sensory branch of the CPN, the lateral sural nerve, which mainly innervates the skin overlying the GL. The absence of effects noted on the GM during TENS further supports this hypothesis as the cutaneous afferents overlying that muscle were not stimulated. The repetitive cutaneous stimulation over the sural nerve, at the lateral malleolus, may have been too distal to stimulate the cutaneous receptors overlying the SO.

  12. Effects of electrical stimulation of olivocochlear fibers in cochlear potentials in the chinchilla.

    PubMed

    Elgueda, Diego; Delano, Paul H; Robles, Luis

    2011-06-01

    The mammalian cochlea has two types of sensory cells; inner hair cells, which receive auditory-nerve afferent innervation, and outer hair cells, innervated by efferent axons of the medial olivocochlear (MOC) system. The role of the MOC system in hearing is still controversial. Recently, by recording cochlear potentials in behaving chinchillas, we suggested that one of the possible functions of the efferent system is to reduce cochlear sensitivity during attention to other sensory modalities (Delano et al. in J Neurosci 27:4146-4153, 2007). However, in spite of these compelling results, the physiological effects of electrical MOC activation on cochlear potentials have not been described in detail in chinchillas. The main objective of the present work was to describe these efferent effects in the chinchilla, comparing them with those in other species and in behavioral experiments. We activated the MOC efferent axons in chinchillas with sectioned middle-ear muscles by applying current pulses at the fourth-ventricle floor. Auditory-nerve compound action potentials (CAP) and cochlear microphonics (CM) were acquired in response to clicks and tones of several frequencies, using a round-window electrode. Electrical efferent stimulation produced CAP amplitude suppressions reaching up to 11 dB. They were higher for low to moderate sound levels. Additionally, CM amplitude increments were found, the largest (≤ 2.5 dB) for low intensity tones. CAP suppression was present at all stimulus frequencies, but was greatest for 2 kHz. CM increments were highest for low-frequency tones, and almost absent at high frequencies. We conclude that the effect obtained in chinchilla is similar to but smaller than that observed in cats, and that the effects seen in awake chinchillas, albeit different in magnitude, are consistent with the activation of efferent fibers.

  13. Electrical Stimulation of Microbial PCB Degradation in Sediment

    PubMed Central

    Chun, Chan Lan; Payne, Rayford B.; Sowers, Kevin R.; May, Harold D.

    2012-01-01

    Bioremediation of polychlorinated biphenyls (PCBs) has been precluded in part by the lack of a cost-effective method to stimulate microbial degradation in situ. A common limitation is the lack of an effective method of providing electron donors and acceptors to promote in situ PCB biodegradation. Application of an electric potential to soil/sediment could be an effective means of providing electron-donors/-acceptors to PCB dechlorinating and degrading microorganisms. In this study, electrical stimulation of microbial PCB dechlorination/ degradation was examined in sediment maintained under simulated in situ conditions. Voltage was applied to open microcosms filled with PCB-impacted (Aroclor 1242) freshwater sediment from a Superfund site (Fox River, WI). The effect of applied low voltages (1.5 to 3.0V) on the microbial transformation of PCBs was determined with: 1) spiked PCBs, and 2) indigenous weathered PCBs. The results indicate that both oxidative and reductive microbial transformation of the spiked PCBs was stimulated but oxidation was dominant and most effective with higher voltage. Chlorobenzoates were produced as oxidation metabolites of the spiked PCBs, but increasing voltage enhanced chlorobenzoate consumption, indicating that overall degradation was enhanced. In the case of weathered PCBs, the total concentration decreased 40–60% in microcosms exposed to electric current while no significant decrease of PCB concentration was observed in control reactors (0 V or sterilized). Single congener analysis of the weathered PCBs showed significant loss of di- to penta-chlorinated congeners, indicating that microbial activity was not limited to anaerobic dechlorination of only higher chlorinated congeners. Degradation was most apparent with the application of only 1.5 V where anodic O2 was not generated, indicating a mechanism of degradation independent of electrolytic O2. Low voltage stimulation of the microbial degradation of weathered PCBs observed in this

  14. Electrical stimulation of microbial PCB degradation in sediment.

    PubMed

    Chun, Chan Lan; Payne, Rayford B; Sowers, Kevin R; May, Harold D

    2013-01-01

    Bioremediation of polychlorinated biphenyls (PCBs) has been precluded in part by the lack of a cost-effective method to stimulate microbial degradation in situ. A common limitation is the lack of an effective method of providing electron donors and acceptors to promote in situ PCB biodegradation. Application of an electric potential to soil/sediment could be an effective means of providing electron-donors/-acceptors to PCB dechlorinating and degrading microorganisms. In this study, electrical stimulation of microbial PCB dechlorination/degradation was examined in sediment maintained under simulated in situ conditions. Voltage was applied to open microcosms filled with PCB-impacted (Aroclor 1242) freshwater sediment from a Superfund site (Fox River, WI). The effect of applied low voltages (1.5-3.0 V) on the microbial transformation of PCBs was determined with: 1) spiked PCBs, and 2) indigenous weathered PCBs. The results indicate that both oxidative and reductive microbial transformation of the spiked PCBs was stimulated but oxidation was dominant and most effective with higher voltage. Chlorobenzoates were produced as oxidation metabolites of the spiked PCBs, but increasing voltage enhanced chlorobenzoate consumption, indicating that overall degradation was enhanced. In the case of weathered PCBs, the total concentration decreased 40-60% in microcosms exposed to electric current while no significant decrease of PCB concentration was observed in control reactors (0 V or sterilized). Single congener analysis of the weathered PCBs showed significant loss of di- to penta-chlorinated congeners, indicating that microbial activity was not limited to anaerobic dechlorination of only higher chlorinated congeners. Degradation was most apparent with the application of only 1.5 V where anodic O(2) was not generated, indicating a mechanism of degradation independent of electrolytic O(2). Low voltage stimulation of the microbial degradation of weathered PCBs observed in this

  15. Tonic Investigation Concept of Cervico-vestibular Muscle Afferents

    PubMed Central

    Dorn, Linda Josephine; Lappat, Annabelle; Neuhuber, Winfried; Scherer, Hans; Olze, Heidi; Hölzl, Matthias

    2016-01-01

    Introduction Interdisciplinary research has contributed greatly to an improved understanding of the vestibular system. To date, however, very little research has focused on the vestibular system's somatosensory afferents. To ensure the diagnostic quality of vestibular somatosensory afferent data, especially the extra cranial afferents, stimulation of the vestibular balance system has to be precluded. Objective Sophisticated movements require intra- and extra cranial vestibular receptors. The study's objective is to evaluate an investigation concept for cervico-vestibular afferents with respect to clinical feasibility. Methods A dedicated chair was constructed, permitting three-dimensional trunk excursions, during which the volunteer's head remains fixed. Whether or not a cervicotonic provocation nystagmus (c-PN) can be induced with static trunk excursion is to be evaluated and if this can be influenced by cervical monophasic transcutaneous electrical nerve stimulation (c-TENS) with a randomized test group. 3D-video-oculography (VOG) was used to record any change in cervico-ocular examination parameters. The occurring nystagmuses were evaluated visually due to the small caliber of nystagmus amplitudes in healthy volunteers. Results The results demonstrate: no influence of placebo-controlled c-TENS on the spontaneous nystagmus; a significant increase of the vertical nystagmus on the 3D-trunk-excursion chair in static trunk flexion with cervical provocation in all young healthy volunteers (n = 49); and a significant difference between vertical and horizontal nystagmuses during static trunk excursion after placebo-controlled c-TENS, except for the horizontal nystagmus during trunk torsion. Conclusion We hope this cervicotonic investigation concept on the 3D trunk-excursion chair will contribute to new diagnostic and therapeutic perspectives on cervical pathologies in vestibular head-to-trunk alignment. PMID:28050208

  16. Dynamic range of safe electrical stimulation of the retina

    NASA Astrophysics Data System (ADS)

    Butterwick, Alexander F.; Vankov, Alexander; Huie, Phil; Palanker, Daniel V.

    2006-02-01

    Electronic retinal prostheses represent a potentially effective approach for restoring some degree of sight in blind patients with retinal degeneration. However, levels of safe electrical stimulation and the underlying mechanisms of cellular damage are largely unknown. We measured the threshold of cellular damage as a function of pulse duration, electrode size, and number of pulses to determine the safe range of stimulation. Measurements were performed in-vitro on embryonic chicken retina with saline-filled glass pipettes for stimulation electrodes. Cellular damage was detected using Propidium Iodide fluorescent staining. Electrode size varied from 115μm to 1mm, pulse duration from 6μs to 6ms, and number of pulses from 1 to 7,500. The threshold current density was independent of electrode sizes exceeding 400μm. With smaller electrodes the current density was scaling reciprocal to the square of the pipette diameter, i.e. acting as a point source so that the damage threshold was determined by the total current in this regime. The damage threshold current measured with large electrodes (1mm) scaled with pulse duration as t -0.5, which is characteristic of electroporation. For repeated electrical pulsed exposure on the retina the threshold current density varied between 0.059 A/cm2 at 6ms to 1.3 A/cm2 at 6μs. The dynamic range of safe stimulation, i.e. the ratio of damage threshold to stimulation threshold was found to be duration-dependent, and varied from 10 to 100 at pulse durations varying between 10μs to 10ms. Maximal dynamic range of 100 was observed near 1ms pulse durations.

  17. Electrical stimulation vs thermal effects in a complex electromagnetic environment.

    PubMed

    Paniagua, Jesús M; Rufo, Montaña; Jiménez, Antonio; Antolín, Alicia; Sánchez, Miguel

    2009-08-01

    Studies linking exposure to low levels of radiofrequencies with adverse health effects, notwithstanding their present apparent inconsistency, have contributed to a steady improvement in the quality of evaluating that exposure. In complex electromagnetic environments, with a multitude of emissions of different frequencies acting simultaneously, knowledge of the spectral content is fundamental to evaluating human exposure to non-ionizing radiation. In the present work, we quantify the most significant spectral components in the frequency band 0.5-2200 MHz in an urban area. The measurements were made with a spectrum analyzer and monopole, biconical, and log-periodic antennas. Power density levels were calculated separately for the medium wave, short wave, and frequency modulation radio broadcasting bands, and for the television and GSM, DCS, and UMTS mobile telephony bands. The measured levels were compared with the ICNIRP reference levels for exposure to multiple frequency sources for thermal effects and electrical stimulation. The results showed the criterion limiting exposure on the basis of preventing electrical stimulation of peripheral nerves and muscles to be stricter (exposure quotient 24.7 10(-4)) than that based on thermal considerations (exposure quotient 0.16 10(-4)). The bands that contribute most to the latter are short wave, with 46.2%, and mobile telephony with 32.6% of the total exposure. In a complex electromagnetic environment, knowledge of the radiofrequency spectrum is essential in order to quantify the contribution of each type of emission to the public's exposure. It is also necessary to evaluate the electrical effects as well as the thermal effects because the criterion to limit exposure on the basis of the effect of the electrical stimulation of tissues is stricter than that based on thermal effects.

  18. 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

  19. Effects of functional electrical stimulation in rehabilitation with hemiparesis patients.

    PubMed

    Tanovic, Edina

    2009-02-01

    Cerebrovascular accident is a focal neurological deficiency occurring suddenly and lasting for more than 24 hours. The purpose of our work is to determine the role of the functional electrical simulation (FES) in the rehabilitation of patients with hemiparesis, which occurred as a consequence of a cerebrovascular accident. This study includes the analysis of two groups of 40 patients with hemiparesis (20 patients with deep hemiparesis and 20 patients with light hemiparesis), a control group which was only treated with kinesiotherapy and a tested group which was treated with kinesiotherapy and functional electrical stimulation. Both groups of patients were analyzed in respect to their sex and age. Additional analysis of the walking function was completed in accordance with the BI and RAP index. The analysis of the basic demographical data demonstrated that there is no significant difference between the control and tested group. The patients of both groups are equal in respect of age and sex. After 4 weeks of rehabilitation of patients with deep and light hemiparesis there were no statistically significant differences between the groups after evaluation by the BI index. However, a statistically significant difference was noted between the groups by the RAP index among patients with deep hemiparesis. After 8 weeks of rehabilitation the group of patients who were treated with kinesiotherapy and functional electrical stimulation showed better statistically significant results of rehabilitation in respect to the control group with both the BI index and the RAP index (p<0,001). In conclusion, we can state that the patients in rehabilitation after a cerebrovascular accident require rehabilitation longer than 4 weeks. Walking rehabilitation after stroke is faster and more successful if we used functional electrical stimulation, in combination with kinesiotherapy, in patients with disabled extremities.

  20. Conditional Electrical Stimulation in Animal and Human Models for Neurogenic Bladder: Working Toward a Neuroprosthesis.

    PubMed

    Powell, C R

    2016-12-01

    Sacral neuromodulation has had a tremendous impact on the treatment of urinary incontinence and lower urinary tract symptoms for patients with neurologic conditions. This stimulation does not use real-time data from the body or input from the patient. Incorporating this is the goal of those pursuing a neuroprosthesis to enhance bladder function for these patients. Investigators have demonstrated the effectiveness of conditional (also called closed-loop) feedback in animal models as well as limited human studies. Dorsal genital nerve, pudendal nerve, S3 afferent nerve roots, S1 and S2 ganglia have all been used as targets for stimulation. Most of these have also been used as sources of afferent nerve information using sophisticated nerve electrode arrays and filtering algorithms to detect significant bladder events and even to estimate the fullness of the bladder. There are problems with afferent nerve sensing, however. Some of these include sensor migration and low signal to noise ratios. Implantable pressure sensors have also been investigated that have their own unique challenges, such as erosion and sensor drift. As technology improves, an intelligent neuroprosthesis with the ability to sense significant bladder events and stimulate as needed will evolve.

  1. Reticulospinal actions on primary afferent depolarization of cutaneous and muscle afferents in the isolated frog neuraxis.

    PubMed

    González, H; Jiménez, I; Rudomin, P

    1993-01-01

    The effects of the brainstem reticular formation on the intraspinal excitability of low threshold cutaneous and muscle afferents were studied in the frog neuraxis isolated together with the right hindlimb nerves. Stimulation of low threshold fibers (less than two times threshold) in cutaneous nerves produced short latency, negative field potentials in the ipsilateral dorsal neuropil (200-400 microns depth) that reversed to positivity at deeper regions (500-700 microns). Stimulation of low threshold fibers (less than two times threshold) in muscle nerves produced, instead, negative response that acquired their maximum amplitude in the ventral neuropil (700-900 microns depth). These electrophysiological findings suggest, in agreement with observations in the cat, that low threshold cutaneous and muscle afferents end at different sites in the spinal cord. Intraspinal microstimulation applied within the dorsal neuropil produced antidromic responses in low threshold cutaneous afferents that were increased in size following stimulation of the dorsal or ventral roots, as well as of the brainstem reticular formation. This increase in excitability is interpreted as being due to primary afferent depolarization (PAD) of the intraspinal terminals of cutaneous fibers. Antidromic responses recorded in muscle nerves following intraspinal stimulation within the ventral neuropil were also increased following conditioning stimulation of adjacent dorsal or ventral roots. However, stimulation of the bulbar reticular formation produced practically no changes in the antidromic responses, but was able to inhibit the PAD of low threshold muscle afferents elicited by stimulation of the dorsal or ventral roots. It is suggested that the PAD of low threshold cutaneous and muscle afferents is mediated by independent sets of interneurons. Reticulospinal fibers would have excitatory connections with the interneurons mediating the PAD of cutaneous fibers and inhibitory connections with the

  2. Preoperative transcutaneous electrical nerve stimulation for localizing superficial nerve paths.

    PubMed

    Natori, Yuhei; Yoshizawa, Hidekazu; Mizuno, Hiroshi; Hayashi, Ayato

    2015-12-01

    During surgery, peripheral nerves are often seen to follow unpredictable paths because of previous surgeries and/or compression caused by a tumor. Iatrogenic nerve injury is a serious complication that must be avoided, and preoperative evaluation of nerve paths is important for preventing it. In this study, transcutaneous electrical nerve stimulation (TENS) was used for an in-depth analysis of peripheral nerve paths. This study included 27 patients who underwent the TENS procedure to evaluate the peripheral nerve path (17 males and 10 females; mean age: 59.9 years, range: 18-83 years) of each patient preoperatively. An electrode pen coupled to an electrical nerve stimulator was used for superficial nerve mapping. The TENS procedure was performed on patients' major peripheral nerves that passed close to the surgical field of tumor resection or trauma surgery, and intraoperative damage to those nerves was apprehensive. The paths of the target nerve were detected in most patients preoperatively. The nerve paths of 26 patients were precisely under the markings drawn preoperatively. The nerve path of one patient substantially differed from the preoperative markings with numbness at the surgical region. During surgery, the nerve paths could be accurately mapped preoperatively using the TENS procedure as confirmed by direct visualization of the nerve. This stimulation device is easy to use and offers highly accurate mapping of nerves for surgical planning without major complications. The authors conclude that TENS is a useful tool for noninvasive nerve localization and makes tumor resection a safe and smooth procedure.

  3. Short-term effects of electrical stimulation superimposed on muscular voluntary contraction in postural control in elderly women.

    PubMed

    Paillard, Thierry; Lafont, Christine; Soulat, Jean Marc; Montoya, Richard; Costes-Salon, Marie-Claude; Dupui, Philippe

    2005-08-01

    Thirty-two women between 62 and 75 years old were randomized into 3 groups. Each group performed a program of 4 sessions a week over 6 weeks. Group SC (n = 11) climbed up and down stairs, group ES (n = 11) practiced electrostimulation, and group SC + ES (n = 10) superimposed the 2 activities simultaneously. Using a force platform and a seesaw platform, static and dynamic balance in eyes-open and eyes-closed conditions were analyzed before and after the programs for each group. After the programs, the results indicated that dynamic balance improved for the 3 groups, but the contribution of visual information in the control of oscillation amplitude was lower in the SC group than in the ES and SC + ES groups. In the SC + ES group, the electrical stimulation interferes with neurophysiologic afference integration in postural control in relation to voluntary movement. Voluntary exercise appears to be more efficient than electrical stimulation and the superimposed techniques to change balancing tactics in the elderly.

  4. Hemispheric asymmetry and somatotopy of afferent inhibition in healthy humans.

    PubMed

    Helmich, R C G; Bäumer, T; Siebner, H R; Bloem, B R; Münchau, A

    2005-11-01

    A conditioning electrical stimulus to a digital nerve can inhibit the motor-evoked potentials (MEPs) in adjacent hand muscles elicited by transcranial magnetic stimulation (TMS) to the contralateral primary motor cortex (M1) when given 25-50 ms before the TMS pulse. This is referred to as short-latency afferent inhibition (SAI). We studied inter-hemispheric differences (Experiment 1) and within-limb somatotopy (Experiment 2) of SAI in healthy right-handers. In Experiment 1, conditioning electrical pulses were applied to the right or left index finger (D2) and MEPs were recorded from relaxed first dorsal interosseus (FDI) and abductor digiti minimi (ADM) muscles ipsilateral to the conditioning stimulus. We found that SAI was more pronounced in right hand muscles. In Experiment 2, electrical stimulation was applied to the right D2 and MEPs were recorded from ipsilateral FDI, extensor digitorum communis (EDC) and biceps brachii (BB) muscles. The amount of SAI did not differ between FDI, EDC and BB muscles. These data demonstrate inter-hemispheric differences in the processing of cutaneous input from the hand, with stronger SAI in the dominant left hemisphere. We also found that SAI occurred not only in hand muscles adjacent to electrical digital stimulation, but also in distant hand and forearm and also proximal arm muscles. This suggests that SAI induced by electrical D2 stimulation is not focal and somatotopically specific, but a more widespread inhibitory phenomenon.

  5. Generation of Electrical Power from Stimulated Muscle Contractions Evaluated

    NASA Technical Reports Server (NTRS)

    Lewandowski, Beth; Kilgore, Kevin; Ercegovic, David B.

    2004-01-01

    This project is a collaborative effort between NASA Glenn Research Center's Revolutionary Aeropropulsion Concepts (RAC) Project, part of the NASA Aerospace Propulsion and Power Program of the Aerospace Technology Enterprise, and Case Western Reserve University's Cleveland Functional Electrical Stimulation (FES) Center. The RAC Project foresees implantable power requirements for future applications such as organically based sensor platforms and robotics that can interface with the human senses. One of the goals of the FES Center is to develop a totally implantable neural prosthesis. This goal is based on feedback from patients who would prefer a system with an internal power source over the currently used system with an external power source. The conversion system under investigation would transform the energy produced from a stimulated muscle contraction into electrical energy. We hypothesize that the output power of the system will be greater than the input power necessary to initiate, sustain, and control the electrical conversion system because of the stored potential energy of the muscle. If the system can be made biocompatible, durable, and with the potential for sustained use, then the biological power source will be a viable solution.

  6. Electro-acoustic stimulation. Acoustic and electric pitch comparisons.

    PubMed

    McDermott, Hugh; Sucher, Catherine; Simpson, Andrea

    2009-01-01

    For simultaneous acoustic and electric stimulation to be perceived as complementary, it may be beneficial for hearing aids and cochlear implants (CI) to be adjusted to provide compatible pitch sensations. To this end, estimates of the pitch perceived for a set of acoustic and electric stimuli were obtained from 14 CI users who had usable low-frequency hearing, either in the non-implanted ear or in both ears. The subjects assigned numerical pitch estimates to each of 5 acoustic pure tones and 5 single-electrode electric pulse trains. On average, the acoustic frequency that corresponded in pitch to stimulation on the most apical electrode was approximately 480 Hz. This was about 1 octave lower than the frequency expected from Greenwood's frequency-place function applied to estimates of the electrode insertion angle based on X-ray images. Furthermore, evidence was found suggesting that pitch decreased with increasing duration of CI use. Pitch estimates from 5 subjects who completed the experiment before experiencing any other sounds through their CI were generally close to the values expected from a recently published frequency map for the cochlear spiral ganglion. Taken together, these findings suggest that some perceptual adaptation may occur that would compensate in part for the apparent mismatch between the intracochlear position of the electrodes and the acoustic frequencies assigned to them in the sound processor.

  7. Yawning induced by focal electrical stimulation in the human brain.

    PubMed

    Joshi, Sweta; Bayat, Arezou; Gagnon, Linda; Shields, Donald C; Koubeissi, Mohamad Z

    2017-01-01

    The primary function of yawning is not fully understood. We report a case in which electrical stimulation of the putamen in the human brain consistently elicited yawning. A 46-year-old woman with intractable epilepsy had invasive depth electrode monitoring and cortical stimulation mapping as part of her presurgical epilepsy evaluation. The first two contacts of a depth electrode that was intended to sample the left insula were in contact with the putamen. Stimulation of these contacts at 6mA and 8mA consistently elicited yawning on two separate days. Engagement in arithmetic and motor tasks during stimulation did not result in yawning. When considering the role of the putamen in motor control and its extensive connectivity to cortical and brainstem regions, our findings suggest that it plays a key role in the execution of motor movements necessitated by yawning. Furthermore, given the role of the anterior insula in attention and focused tasks, activation of this area while engaged in arithmetic and motor tasks could inhibit the putaminal processing necessary for yawning. Many have hypothesized the function of yawning; however, it remains debatable whether yawning serves a primarily physiological or communicative function or perhaps both.

  8. Modulating Human Auditory Processing by Transcranial Electrical Stimulation

    PubMed Central

    Heimrath, Kai; Fiene, Marina; Rufener, Katharina S.; Zaehle, Tino

    2016-01-01

    Transcranial electrical stimulation (tES) has become a valuable research tool for the investigation of neurophysiological processes underlying human action and cognition. In recent years, striking evidence for the neuromodulatory effects of transcranial direct current stimulation, transcranial alternating current stimulation, and transcranial random noise stimulation has emerged. While the wealth of knowledge has been gained about tES in the motor domain and, to a lesser extent, about its ability to modulate human cognition, surprisingly little is known about its impact on perceptual processing, particularly in the auditory domain. Moreover, while only a few studies systematically investigated the impact of auditory tES, it has already been applied in a large number of clinical trials, leading to a remarkable imbalance between basic and clinical research on auditory tES. Here, we review the state of the art of tES application in the auditory domain focussing on the impact of neuromodulation on acoustic perception and its potential for clinical application in the treatment of auditory related disorders. PMID:27013969

  9. Different Mode of Afferents Determines the Frequency Range of High Frequency Activities in the Human Brain: Direct Electrocorticographic Comparison between Peripheral Nerve and Direct Cortical Stimulation

    PubMed Central

    Kobayashi, Katsuya; Matsumoto, Riki; Matsuhashi, Masao; Usami, Kiyohide; Shimotake, Akihiro; Kunieda, Takeharu; Kikuchi, Takayuki; Mikuni, Nobuhiro; Miyamoto, Susumu; Fukuyama, Hidenao; Takahashi, Ryosuke; Ikeda, Akio

    2015-01-01

    Physiological high frequency activities (HFA) are related to various brain functions. Factors, however, regulating its frequency have not been well elucidated in humans. To validate the hypothesis that different propagation modes (thalamo-cortical vs. cortico-coritcal projections), or different terminal layers (layer IV vs. layer II/III) affect its frequency, we, in the primary somatosensory cortex (SI), compared HFAs induced by median nerve stimulation with those induced by electrical stimulation of the cortex connecting to SI. We employed 6 patients who underwent chronic subdural electrode implantation for presurgical evaluation. We evaluated the HFA power values in reference to the baseline overriding N20 (earliest cortical response) and N80 (late response) of somatosensory evoked potentials (HFASEP(N20) and HFASEP(N80)) and compared those overriding N1 and N2 (first and second responses) of cortico-cortical evoked potentials (HFACCEP(N1) and HFACCEP(N2)). HFASEP(N20) showed the power peak in the frequency above 200 Hz, while HFACCEP(N1) had its power peak in the frequency below 200 Hz. Different propagation modes and/or different terminal layers seemed to determine HFA frequency. Since HFACCEP(N1) and HFA induced during various brain functions share a similar broadband profile of the power spectrum, cortico-coritcal horizontal propagation seems to represent common mode of neural transmission for processing these functions. PMID:26087042

  10. Different Mode of Afferents Determines the Frequency Range of High Frequency Activities in the Human Brain: Direct Electrocorticographic Comparison between Peripheral Nerve and Direct Cortical Stimulation.

    PubMed

    Kobayashi, Katsuya; Matsumoto, Riki; Matsuhashi, Masao; Usami, Kiyohide; Shimotake, Akihiro; Kunieda, Takeharu; Kikuchi, Takayuki; Mikuni, Nobuhiro; Miyamoto, Susumu; Fukuyama, Hidenao; Takahashi, Ryosuke; Ikeda, Akio

    2015-01-01

    Physiological high frequency activities (HFA) are related to various brain functions. Factors, however, regulating its frequency have not been well elucidated in humans. To validate the hypothesis that different propagation modes (thalamo-cortical vs. cortico-coritcal projections), or different terminal layers (layer IV vs. layer II/III) affect its frequency, we, in the primary somatosensory cortex (SI), compared HFAs induced by median nerve stimulation with those induced by electrical stimulation of the cortex connecting to SI. We employed 6 patients who underwent chronic subdural electrode implantation for presurgical evaluation. We evaluated the HFA power values in reference to the baseline overriding N20 (earliest cortical response) and N80 (late response) of somatosensory evoked potentials (HFA(SEP(N20)) and HFA(SEP(N80))) and compared those overriding N1 and N2 (first and second responses) of cortico-cortical evoked potentials (HFA(CCEP(N1)) and HFA(CCEP(N2))). HFA(SEP(N20)) showed the power peak in the frequency above 200 Hz, while HFA(CCEP(N1)) had its power peak in the frequency below 200 Hz. Different propagation modes and/or different terminal layers seemed to determine HFA frequency. Since HFA(CCEP(N1)) and HFA induced during various brain functions share a similar broadband profile of the power spectrum, cortico-coritcal horizontal propagation seems to represent common mode of neural transmission for processing these functions.

  11. Bio-robots automatic navigation with electrical reward stimulation.

    PubMed

    Sun, Chao; Zhang, Xinlu; Zheng, Nenggan; Chen, Weidong; Zheng, Xiaoxiang

    2012-01-01

    Bio-robots that controlled by outer stimulation through brain computer interface (BCI) suffer from the dependence on realtime guidance of human operators. Current automatic navigation methods for bio-robots focus on the controlling rules to force animals to obey man-made commands, with animals' intelligence ignored. This paper proposes a new method to realize the automatic navigation for bio-robots with electrical micro-stimulation as real-time rewards. Due to the reward-seeking instinct and trial-and-error capability, bio-robot can be steered to keep walking along the right route with rewards and correct its direction spontaneously when rewards are deprived. In navigation experiments, rat-robots learn the controlling methods in short time. The results show that our method simplifies the controlling logic and realizes the automatic navigation for rat-robots successfully. Our work might have significant implication for the further development of bio-robots with hybrid intelligence.

  12. Photoacoustic microscopy of microvascular responses to cortical electrical stimulation

    NASA Astrophysics Data System (ADS)

    Tsytsarev, Vassiliy; Hu, Song; Yao, Junjie; Maslov, Konstantin; Barbour, Dennis L.; Wang, Lihong V.

    2011-07-01

    Advances in the functional imaging of cortical hemodynamics have greatly facilitated the understanding of neurovascular coupling. In this study, label-free optical-resolution photoacoustic microscopy (OR-PAM) was used to monitor microvascular responses to direct electrical stimulations of the mouse somatosensory cortex through a cranial opening. The responses appeared in two forms: vasoconstriction and vasodilatation. The transition between these two forms of response was observed in single vessels by varying the stimulation intensity. Marked correlation was found between the current-dependent responses of two daughter vessels bifurcating from the same parent vessel. Statistical analysis of twenty-seven vessels from three different animals further characterized the spatial-temporal features and the current dependence of the microvascular response. Our results demonstrate that OR-PAM is a valuable tool to study neurovascular coupling at the microscopic level.

  13. Nonparametric Model of Smooth Muscle Force Production During Electrical Stimulation.

    PubMed

    Cole, Marc; Eikenberry, Steffen; Kato, Takahide; Sandler, Roman A; Yamashiro, Stanley M; Marmarelis, Vasilis Z

    2017-03-01

    A nonparametric model of smooth muscle tension response to electrical stimulation was estimated using the Laguerre expansion technique of nonlinear system kernel estimation. The experimental data consisted of force responses of smooth muscle to energy-matched alternating single pulse and burst current stimuli. The burst stimuli led to at least a 10-fold increase in peak force in smooth muscle from Mytilus edulis, despite the constant energy constraint. A linear model did not fit the data. However, a second-order model fit the data accurately, so the higher-order models were not required to fit the data. Results showed that smooth muscle force response is not linearly related to the stimulation power.

  14. Restoration of movement using functional electrical stimulation and Bayes' theorem.

    PubMed

    Seifert, Heather M; Fuglevand, Andrew J

    2002-11-01

    Various computational approaches have been applied to predict aspects of animal behavior from the recorded activity of populations of neurons. Here we invert this process to predict the requisite neuromuscular activity associated with specified motor behaviors. A probabilistic method based on Bayes' theorem was used to predict the patterns of muscular activity needed to produce various types of desired finger movements. The profiles of predicted activity were then used to drive frequency-modulated muscle stimulators to evoke multijoint finger movements. Comparison of movements generated by electrical stimulation with desired movements yielded root mean squared errors between approximately 18 and 26%. This reasonable correspondence between desired and evoked movements suggests that this approach might serve as a useful strategy to control neuroprosthetic systems that aim to restore movement to paralyzed individuals.

  15. Calcium Activation Profile In Electrically Stimulated Intact Rat Heart Cells

    NASA Astrophysics Data System (ADS)

    Geerts, Hugo; Nuydens, Rony; Ver Donck, Luc; Nuyens, Roger; De Brabander, Marc; Borgers, Marcel

    1988-06-01

    Recent advances in fluorescent probe technology and image processing equipment have made available the measurement of calcium in living systems on a real-time basis. We present the use of the calcium indicator Fura-2 in intact normally stimulated rat heart cells for the spatial and dynamic measurement of the calcium excitation profile. After electric stimulation (1 Hz), the activation proceeds from the center of the myocyte toward the periphery. Within two frame times (80 ms), the whole cell is activated. The activation is slightly faster in the center of the cell than in the periphery. The mean recovery time is 200-400 ms. There is no difference along the cell's long axis. The effect of a beta-agonist and of a calcium antagonist is described.

  16. Technical Rebuilding of Movement Function Using Functional Electrical Stimulation

    NASA Astrophysics Data System (ADS)

    Gföhler, Margit

    To rebuild lost movement functions, neuroprostheses based on functional electrical stimulation (FES) artificially activate skeletal muscles in corresponding sequences, using both residual body functions and artificial signals for control. Besides the functional gain, FES training also brings physiological and psychological benefits for spinal cord-injured subjects. In this chapter, current stimulation technology and the main components of FES-based neuroprostheses including enhanced control systems are presented. Technology and application of FES cycling and rowing, both approaches that enable spinal cord-injured subjects to participate in mainstream activities and improve their health and fitness by exercising like able-bodied subjects, are discussed in detail, and an overview of neuroprostheses that aim at restoring movement functions for daily life as walking or grasping is given.

  17. Electric stimulation of periventricular heterotopia: participation in higher cerebral functions.

    PubMed

    Wagner, Jan; Elger, Christian E; Urbach, Horst; Bien, Christian G

    2009-02-01

    Gray matter heterotopia are a common cause of pharmacoresistant epilepsy. Recently, several case studies have addressed the question of whether heterotopia can contribute to physiological cerebral functions. We describe two cases that demonstrate a functional role for periventricular heterotopia in higher cognitive processes. During presurgical diagnostics, two patients underwent electric stimulation of both the periventricular heterotopia and the overlying cortex. This revealed a functional role of periventricular heterotopia in higher cerebral functions such as language and complex visual and acoustic processing. Furthermore, stimulation of the overlying cortex led to unusually intense positive phenomena, including complex acoustic and gustatory hallucinations and language production. These cases illustrate that periventricular heterotopic neurons can contribute to higher cerebral functions. Interestingly, the anterior-to-posterior representation of these functions is comparable to the normal anterior-to-posterior representation in a normal neocortex (similar to a periventricular "minicortex" in early developmental stages).

  18. Visualizing simulated electrical fields from electroencephalography and transcranial electric brain stimulation: a comparative evaluation.

    PubMed

    Eichelbaum, Sebastian; Dannhauer, Moritz; Hlawitschka, Mario; Brooks, Dana; Knösche, Thomas R; Scheuermann, Gerik

    2014-11-01

    Electrical activity of neuronal populations is a crucial aspect of brain activity. This activity is not measured directly but recorded as electrical potential changes using head surface electrodes (electroencephalogram - EEG). Head surface electrodes can also be deployed to inject electrical currents in order to modulate brain activity (transcranial electric stimulation techniques) for therapeutic and neuroscientific purposes. In electroencephalography and noninvasive electric brain stimulation, electrical fields mediate between electrical signal sources and regions of interest (ROI). These fields can be very complicated in structure, and are influenced in a complex way by the conductivity profile of the human head. Visualization techniques play a central role to grasp the nature of those fields because such techniques allow for an effective conveyance of complex data and enable quick qualitative and quantitative assessments. The examination of volume conduction effects of particular head model parameterizations (e.g., skull thickness and layering), of brain anomalies (e.g., holes in the skull, tumors), location and extent of active brain areas (e.g., high concentrations of current densities) and around current injecting electrodes can be investigated using visualization. Here, we evaluate a number of widely used visualization techniques, based on either the potential distribution or on the current-flow. In particular, we focus on the extractability of quantitative and qualitative information from the obtained images, their effective integration of anatomical context information, and their interaction. We present illustrative examples from clinically and neuroscientifically relevant cases and discuss the pros and cons of the various visualization techniques.

  19. Visualizing Simulated Electrical Fields from Electroencephalography and Transcranial Electric Brain Stimulation: A Comparative Evaluation

    PubMed Central

    Eichelbaum, Sebastian; Dannhauer, Moritz; Hlawitschka, Mario; Brooks, Dana; Knösche, Thomas R.; Scheuermann, Gerik

    2014-01-01

    Electrical activity of neuronal populations is a crucial aspect of brain activity. This activity is not measured directly but recorded as electrical potential changes using head surface electrodes (electroencephalogram - EEG). Head surface electrodes can also be deployed to inject electrical currents in order to modulate brain activity (transcranial electric stimulation techniques) for therapeutic and neuroscientific purposes. In electroencephalography and noninvasive electric brain stimulation, electrical fields mediate between electrical signal sources and regions of interest (ROI). These fields can be very complicated in structure, and are influenced in a complex way by the conductivity profile of the human head. Visualization techniques play a central role to grasp the nature of those fields because such techniques allow for an effective conveyance of complex data and enable quick qualitative and quantitative assessments. The examination of volume conduction effects of particular head model parameterizations (e.g., skull thickness and layering), of brain anomalies (e.g., holes in the skull, tumors), location and extent of active brain areas (e.g., high concentrations of current densities) and around current injecting electrodes can be investigated using visualization. Here, we evaluate a number of widely used visualization techniques, based on either the potential distribution or on the current-flow. In particular, we focus on the extractability of quantitative and qualitative information from the obtained images, their effective integration of anatomical context information, and their interaction. We present illustrative examples from clinically and neuroscientifically relevant cases and discuss the pros and cons of the various visualization techniques. PMID:24821532

  20. Optimal delineation of single C-tactile and C-nociceptive afferents in humans by latency slowing.

    PubMed

    Watkins, Roger H; Wessberg, Johan; Backlund Wasling, Helena; Dunham, James P; Olausson, Håkan; Johnson, Richard D; Ackerley, Rochelle

    2017-04-01

    C-mechanoreceptors in humans comprise a population of unmyelinated afferents exhibiting a wide range of mechanical sensitivities. C-mechanoreceptors are putatively divided into those signaling gentle touch (C-tactile afferents, CTs) and nociception (C-mechanosensitive nociceptors, CMs), giving rise to positive and negative affect, respectively. We sought to distinguish, compare, and contrast the properties of a population of human C-mechanoreceptors to see how fundamental the divisions between these putative subpopulations are. We used microneurography to record from individual afferents in humans and applied electrical and mechanical stimulation to their receptive fields. We show that C-mechanoreceptors can be distinguished unequivocally into two putative populations, comprising CTs and CMs, by electrically evoked spike latency changes (slowing). After both natural mechanical stimulation and repetitive electrical stimulation there was markedly less latency slowing in CTs compared with CMs. Electrical receptive field stimulation, which bypasses the receptor end organ, was most effective in classifying C-mechanoreceptors, as responses to mechanical receptive field stimulation overlapped somewhat, which may lead to misclassification. Furthermore, we report a subclass of low-threshold CM responding to gentle mechanical stimulation and a potential subclass of CT afferent displaying burst firing. We show that substantial differences exist in the mechanisms governing axonal conduction between CTs and CMs. We provide clear electrophysiological "signatures" (extent of latency slowing) that can be used in unequivocally identifying populations of C-mechanoreceptors in single-unit and multiunit microneurography studies and in translational animal research into affective touch. Additionally, these differential mechanisms may be pharmacologically targetable for separate modulation of positive and negative affective touch information.NEW & NOTEWORTHY Human skin encodes a

  1. The organization of primary afferent depolarization in the isolated spinal cord of the frog

    PubMed Central

    Carpenter, D. O.; Rudomin, P.

    1973-01-01

    1. The organization of primary afferent depolarization (PAD) produced by excitation of peripheral sensory and motor nerves was studied in the frog cord isolated with hind limb nerves. 2. Dorsal root potentials from sensory fibres (DR-DRPs) were evoked on stimulation of most sensory nerves, but were largest from cutaneous, joint and flexor muscle afferents. With single shock stimulation the largest cutaneous and joint afferent fibres gave DR-DRPs, but potentials from muscle nerves resulted from activation of sensory fibres with thresholds to electrical stimulation higher than 1·2-1·5 times the threshold of the most excitable fibres in the nerve. This suggests that PAD from muscle afferents is probably due to excitation of extrafusal receptors. 3. Dorsal root potentials produced by antidromic activation of motor fibres (VR-DRPs) were larger from extensor muscles and smaller or absent from flexor muscles. The VR-DRPs were produced by activation of the lowest threshold motor fibres. 4. Three types of interactions were found between test and conditioning DRPs from the same or different nerves. With maximal responses occlusion was usually pronounced. At submaximal levels linear summation occurred. Near threshold the conditioning stimulus frequently resulted in a large facilitation of the test DRP. All three types of interactions were found with two DR-DRPs, two VR-DRPs or one DR-DRP and one VR-DRP. 5. The excitability of sensory nerve terminals from most peripheral nerves was increased during the DR-DRP. The magnitude of the excitability increase varied roughly with the magnitude of the DR-DRP evoked by the conditioning stimulus. 6. There was a marked excitability increase of cutaneous and extensor muscle afferent terminals during the VR-DRP. Flexor muscle afferent terminals often showed no excitability changes to ventral root stimulation. In those experiments where afferent terminals from flexor muscles did show an excitability increase, the effects were smaller than

  2. New Perspectives in Edema Control via Electrical Stimulation

    PubMed Central

    Mendel, Frank C.; Fish, Dale R.

    1993-01-01

    Clinicians commonly use electrical stimulation (ES) to control acute edema. But, except for anecdotal reports, there is little evidence to support that practice. We recently conducted a series of controlled, blinded studies on several nonhuman animal models to determine the efficacy of several forms of ES, but high-voltage pulsed current (HVPC) in particular, in controlling acute posttraumatic edema. We observed that acute posttraumatic edema is curbed by HVPC when certain protocols are used. Results of these studies suggest to us that wave form, polarity, treatment schedule, intensity and frequency of pulses all influence ES, and that clinical protocols need revision. PMID:16558209

  3. Neuronal excitability level transition induced by electrical stimulation

    NASA Astrophysics Data System (ADS)

    Florence, G.; Kurths, J.; Machado, B. S.; Fonoff, E. T.; Cerdeira, H. A.; Teixeira, M. J.; Sameshima, K.

    2014-12-01

    In experimental studies, electrical stimulation (ES) has been applied to induce neuronal activity or to disrupt pathological patterns. Nevertheless, the underlying mechanisms of these activity pattern transitions are not clear. To study these phenomena, we simulated a model of the hippocampal region CA1. The computational simulations using different amplitude levels and duration of ES revealed three states of neuronal excitability: burst-firing mode, depolarization block and spreading depression wave. We used the bifurcation theory to analyse the interference of ES in the cellular excitability and the neuronal dynamics. Understanding this process would help to improve the ES techniques to control some neurological disorders.

  4. Gastric Electrical Stimulation and Sacral Electrical Stimulation: A Long-Term Follow-Up Study of Dual-Device Treatment

    PubMed Central

    Agrawal, Anubhav; Francis, Sean Lamar; Deveneau, Nicolette Elizabeth; Jain, Shaily; Abrasley, Christopher; McNeese, Jason Trippe; Kothari, Shivangi T.; Lahr, Christopher J.

    2016-01-01

    Aims The objective of this study was to investigate sacral electrical stimulation (SES) and gastric electrical stimulation (GES) by comparing upper and lower gastrointestinal (GI) and genitourinary (GU) symptoms and quality of life, before treatment and in the long term after treatment. We hypothesized that dual-device treatment would greatly improve upper and lower gastrointestinal and genitourinary symptoms, as well as quality of life. Methods Fifty-four patients who underwent dual-device treatment (GES and SES) were enrolled in this study. Patients who had surpassed 24 months since the second-device insertion were included. Patients were evaluated before and after both devices were implanted and given a symptom questionnaire regarding their upper GI, lower GI, and GU symptoms and their quality of life. Results With combined treatment, a statistically significant improvement was seen in upper GI, lower GI, and GU symptoms and quality of life. However, fecal incontinence and fecal urgency improvements did not reach statistical significance, likely due to the small sample size. Conclusion The implantation of two stimulators appears to be safe and effective to improve patients’ quality of life for those with upper GI symptoms, bowel problems, and bladder dysfunction. PMID:26280085

  5. 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

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

    PubMed

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

    2014-12-01

    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.

  7. [About optimized designs and circuits of autonomous electric stimulators for the gastrointestinal tract].

    PubMed

    Glushchuk, S F

    2004-01-01

    Described in the paper are the key principles of designing of autonomous electrodes for the gastrointestinal tract (AE GT) as well as circuits of stimulating-pulse generators. A shape for the electric-stimulator frame, its geometric dimensions and choice of a material for electrodes are substantiated. The electric- and trauma-safety of AE GT is discussed. The main stimulating current parameters, as well as the flowchart and design of the electric stimulator are presented.

  8. Transcranial electric stimulation entrains cortical neuronal populations in rats

    PubMed Central

    Ozen, Simal; Sirota, Anton; Belluscio, Mariano A.; Anastassiou, Costas A.; Stark, Eran; Koch, Christof; Buzsáki, György

    2010-01-01

    Low intensity electric fields have been suggested to affect the ongoing neuronal activity in vitro and in human studies. However, the physiological mechanism of how weak electrical fields affect and interact with intact brain activity is not well understood. We performed in vivo extracellular and intracellular recordings from the neocortex and hippocampus of anaesthetized rats and extracellular recordings in behaving rats. Electric fields were generated by sinusoid patterns at slow frequency (0.8, 1.25 or 1.7 Hz) via electrodes placed on the surface of the skull or the dura. Transcranial electric stimulation (TES) reliably entrained neurons in widespread cortical areas, including the hippocampus. The percentage of TES phase-locked neurons increased with stimulus intensity and depended on the behavioral state of the animal. TES-induced voltage gradient, as low as 1 mV/mm at the recording sites, was sufficient to phase-bias neuronal spiking. Intracellular recordings showed that both spiking and subthreshold activity were under the combined influence of TES forced fields and network activity. We suggest that TES in chronic preparations may be used for experimental and therapeutic control of brain activity. PMID:20739569

  9. Responses of muscle spindles in feline dorsal neck muscles to electrical stimulation of the cervical sympathetic nerve.

    PubMed

    Hellström, F; Roatta, S; Thunberg, J; Passatore, M; Djupsjöbacka, M

    2005-09-01

    Previous studies performed in jaw muscles of rabbits and rats have demonstrated that sympathetic outflow may affect the activity of muscle spindle afferents (MSAs). The resulting impairment of MSA information has been suggested to be involved in the genesis and spread of chronic muscle pain. The present study was designed to investigate sympathetic influences on muscle spindles in feline trapezius and splenius muscles (TrSp), as these muscles are commonly affected by chronic pain in humans. Experiments were carried out in cats anesthetized with alpha-chloralose. The effect of electrical stimulation (10 Hz for 90 s or 3 Hz for 5 min) of the peripheral stump of the cervical sympathetic nerve (CSN) was investigated on the discharge of TrSp MSAs (units classified as Ia-like and II-like) and on their responses to sinusoidal stretching of these muscles. In some of the experiments, the local microcirculation of the muscles was monitored by laser Doppler flowmetry. In total, 46 MSAs were recorded. Stimulation of the CSN at 10 Hz powerfully depressed the mean discharge rate of the majority of the tested MSAs (73%) and also affected the sensitivity of MSAs to sinusoidal changes of muscle length, which were evaluated in terms of amplitude and phase of the sinusoidal fitting of unitary activity. The amplitude was significantly reduced in Ia-like units and variably affected in II-like units, while in general the phase was affected little and not changed significantly in either group. The discharge of a smaller percentage of tested units was also modulated by 3-Hz CSN stimulation. Blockade of the neuromuscular junctions by pancuronium did not induce any changes in MSA responses to CSN stimulation, showing that these responses were not secondary to changes in extrafusal or fusimotor activity. Further data showed that the sympathetically induced modulation of MSA discharge was not secondary to the concomitant reduction of muscle blood flow induced by the stimulation. Hence

  10. BCI-Triggered Functional Electrical Stimulation Therapy for Upper Limb

    PubMed Central

    Marquez-Chin, Cesar; Marquis, Aaron; Popovic, Milos R.

    2016-01-01

    We present here the integration of brain-computer interfacing (BCI) technology with functional electrical stimulation therapy to restore voluntary function. The system was tested with a single man with chronic (6 years) severe left hemiplegia resulting from a stroke. The BCI, implemented as a simple “brain-switch” activated by power decreases in the 18 Hz – 28 Hz frequency range of the participant’s electroencephalograpic signals, triggered a neuroprosthesis designed to facilitate forward reaching, reaching to the mouth, and lateral reaching movements. After 40 90-minute sessions in which the participant attempted the reaching tasks repeatedly, with the movements assisted by the BCI-triggered neuroprosthesis, the participant’s arm function showed a clinically significant six point increase in the Fugl-Meyer Asessment Upper Extermity Sub-Score. These initial results suggest that the combined use of BCI and functional electrical stimulation therapy may restore voluntary reaching function in individuals with chronic severe hemiplegia for whom the rehabilitation alternatives are very limited. PMID:27990247

  11. Programmable and on-demand drug release using electrical stimulation

    PubMed Central

    Yi, Y. T.; Sun, J. Y.; Lu, Y. W.; Liao, Y. C.

    2015-01-01

    Recent advancement in microfabrication has enabled the implementation of implantable drug delivery devices with precise drug administration and fast release rates at specific locations. This article presents a membrane-based drug delivery device, which can be electrically stimulated to release drugs on demand with a fast release rate. Hydrogels with ionic model drugs are sealed in a cylindrical reservoir with a separation membrane. Electrokinetic forces are then utilized to drive ionic drug molecules from the hydrogels into surrounding bulk solutions. The drug release profiles of a model drug show that release rates from the device can be electrically controlled by adjusting the stimulated voltage. When a square voltage wave is applied, the device can be quickly switched between on and off to achieve pulsatile release. The drug dose released is then determined by the duration and amplitude of the applied voltages. In addition, successive on/off cycles can be programmed in the voltage waveforms to generate consistent and repeatable drug release pulses for on-demand drug delivery. PMID:25825612

  12. Emerging technology: electrical stimulation in obstructive sleep apnoea

    PubMed Central

    Steier, Joerg

    2015-01-01

    Electrical stimulation (ES) of the upper airway (UAW) dilator muscles for patients with obstructive sleep apnoea (OSA) has been used for several decades, but in recent years research in this field has experienced a renaissance; the results of several studies have triggered a steady rise in the interest in this topic. Prospective trials, although still lacking a sham-controlled and randomised approach, have revealed the potential of ES. Hypoglossal nerve stimulation (HNS) leads to a significant reduction in the apnoea-hypopnoea index and the oxygen desaturation index (ODI). There are similar results published from feasibility studies for transcutaneous ES. A limitation of HNS remains the invasive procedure, the costs involved and severe adverse events, while for the non-invasive approach complications are rare and limited. The limiting step for transcutaneous ES is to deliver a sufficient current without causing arousal from sleep. Despite the progress up to date, numerous variables including optimal stimulation settings, different devices and procedures remain to be further defined for the invasive and the non-invasive method. Further studies are required to identify which patients respond to this treatment. ES of the UAW dilator muscles in OSA has the potential to develop into a clinical alternative to continuous positive airway pressure (CPAP) therapy. It could benefit selected patients who fail standard therapy due to poor long-term compliance. It is likely that international societies will need to review and update their existing guidance on the use of ES in OSA. PMID:26380757

  13. Reinnervation of renal afferent and efferent nerves at 5.5 and 11 months after catheter-based radiofrequency renal denervation in sheep.

    PubMed

    Booth, Lindsea C; Nishi, Erika E; Yao, Song T; Ramchandra, Rohit; Lambert, Gavin W; Schlaich, Markus P; May, Clive N

    2015-02-01

    Previous studies indicate that catheter-based renal denervation reduces blood pressure and renal norepinephrine spillover in human resistant hypertension. The effects of this procedure on afferent sensory and efferent sympathetic renal nerves, and the subsequent degree of reinnervation, have not been investigated. We therefore examined the level of functional and anatomic reinnervation at 5.5 and 11 months after renal denervation using the Symplicity Flex catheter. In normotensive anesthetized sheep (n=6), electric stimulation of intact renal nerves increased arterial pressure from 99±3 to 107±3 mm Hg (afferent response) and reduced renal blood flow from 198±16 to 85±20 mL/min (efferent response). In a further group (n=6), immediately after denervation, renal sympathetic nerve activity was absent and the responses to electric stimulation were abolished. At 11 months after denervation (n=5), renal sympathetic nerve activity and the responses to electric stimulation were at normal levels. Immunohistochemical staining for renal efferent (tyrosine hydroxylase) and renal afferent nerves (calcitonin gene-related peptide), as well as renal norepinephrine levels, was normal 11 months after denervation. Findings at 5.5 months after denervation were similar (n=5). In summary, catheter-based renal denervation effectively ablated the renal afferent and efferent nerves in normotensive sheep. By 11 months after denervation the functional afferent and efferent responses to electric stimulation were normal. Reinnervation at 11 months after denervation was supported by normal anatomic distribution of afferent and efferent renal nerves. In view of this evidence, the mechanisms underlying the prolonged hypotensive effect of catheter-based renal denervation in human resistant hypertension need to be reassessed.

  14. Influence of electrical stimulation on hip joint adductor muscle activity during maximum effort.

    PubMed

    Nakano, Sota; Wada, Chikamune

    2016-05-01

    [Purpose] This study investigated whether hip adductor activity was influenced by electrical stimulation of the tensor fascia lata muscle. [Subjects and Methods] The subjects were 16 nondisabled males. Each subject was asked to adduct the hip joint with maximum effort. The electromyogram of the adductor longus was recorded under two experimental conditions, with and without electrical stimulation of the tensor fascia lata. [Results] In the presence of electrical stimulation, muscle activity decreased to 72.9% (57.8-89.3%) of that without stimulation. [Conclusion] These results suggested that inactivation of the adductor group was promoted by electrical stimulation of the tensor fascia lata.

  15. Influence of electrical stimulation on hip joint adductor muscle activity during maximum effort

    PubMed Central

    Nakano, Sota; Wada, Chikamune

    2016-01-01

    [Purpose] This study investigated whether hip adductor activity was influenced by electrical stimulation of the tensor fascia lata muscle. [Subjects and Methods] The subjects were 16 nondisabled males. Each subject was asked to adduct the hip joint with maximum effort. The electromyogram of the adductor longus was recorded under two experimental conditions, with and without electrical stimulation of the tensor fascia lata. [Results] In the presence of electrical stimulation, muscle activity decreased to 72.9% (57.8–89.3%) of that without stimulation. [Conclusion] These results suggested that inactivation of the adductor group was promoted by electrical stimulation of the tensor fascia lata. PMID:27313387

  16. A Murine Model of Muscle Training by Neuromuscular Electrical Stimulation

    PubMed Central

    Ambrosio, Fabrisia; Fitzgerald, G. Kelley; Ferrari, Ricardo; Distefano, Giovanna; Carvell, George

    2012-01-01

    Neuromuscular electrical stimulation (NMES) is a common clinical modality that is widely used to restore1, maintain2 or enhance3-5 muscle functional capacity. Transcutaneous surface stimulation of skeletal muscle involves a current flow between a cathode and an anode, thereby inducing excitement of the motor unit and the surrounding muscle fibers. NMES is an attractive modality to evaluate skeletal muscle adaptive responses for several reasons. First, it provides a reproducible experimental model in which physiological adaptations, such as myofiber hypertophy and muscle strengthening6, angiogenesis7-9, growth factor secretion9-11, and muscle precursor cell activation12 are well documented. Such physiological responses may be carefully titrated using different parameters of stimulation (for Cochrane review, see 13). In addition, NMES recruits motor units non-selectively, and in a spatially fixed and temporally synchronous manner14, offering the advantage of exerting a treatment effect on all fibers, regardless of fiber type. Although there are specified contraindications to NMES in clinical populations, including peripheral venous disorders or malignancy, for example, NMES is safe and feasible, even for those who are ill and/or bedridden and for populations in which rigorous exercise may be challenging. Here, we demonstrate the protocol for adapting commercially available electrodes and performing a NMES protocol using a murine model. This animal model has the advantage of utilizing a clinically available device and providing instant feedback regarding positioning of the electrode to elicit the desired muscle contractile effect. For the purpose of this manuscript, we will describe the protocol for muscle stimulation of the anterior compartment muscles of a mouse hindlimb. PMID:22617846

  17. A murine model of muscle training by neuromuscular electrical stimulation.

    PubMed

    Ambrosio, Fabrisia; Fitzgerald, G Kelley; Ferrari, Ricardo; Distefano, Giovanna; Carvell, George

    2012-05-09

    Neuromuscular electrical stimulation (NMES) is a common clinical modality that is widely used to restore (1), maintain (2) or enhance (3-5) muscle functional capacity. Transcutaneous surface stimulation of skeletal muscle involves a current flow between a cathode and an anode, thereby inducing excitement of the motor unit and the surrounding muscle fibers. NMES is an attractive modality to evaluate skeletal muscle adaptive responses for several reasons. First, it provides a reproducible experimental model in which physiological adaptations, such as myofiber hypertophy and muscle strengthening (6), angiogenesis (7-9), growth factor secretion (9-11), and muscle precursor cell activation (12) are well documented. Such physiological responses may be carefully titrated using different parameters of stimulation (for Cochrane review, see (13)). In addition, NMES recruits motor units non-selectively, and in a spatially fixed and temporally synchronous manner (14), offering the advantage of exerting a treatment effect on all fibers, regardless of fiber type. Although there are specified contraindications to NMES in clinical populations, including peripheral venous disorders or malignancy, for example, NMES is safe and feasible, even for those who are ill and/or bedridden and for populations in which rigorous exercise may be challenging. Here, we demonstrate the protocol for adapting commercially available electrodes and performing a NMES protocol using a murine model. This animal model has the advantage of utilizing a clinically available device and providing instant feedback regarding positioning of the electrode to elicit the desired muscle contractile effect. For the purpose of this manuscript, we will describe the protocol for muscle stimulation of the anterior compartment muscles of a mouse hindlimb.

  18. Organ of Corti Micromechanics with Local Electrical Stimulation

    NASA Astrophysics Data System (ADS)

    Chen, Fangyi; Zheng, Jiefu; Choudhury, Niloy; Jaques, Steve; Nuttall, Alfred L.

    2009-02-01

    Optical low coherence interferometry is able to both image and measure the vibration of the cellular and non-cellular structures of the organ of Corti in vivo. In this study we applied an electric current to the basal turn from a pair of electrodes, one in scala tympani and the other in scala vestibuli, at the location corresponding to ~17 kHz when interferometry measurements were made. The coherence gate of the interferometer was positioned 1) at the basilar membrane (BM) near the radial location of the outer hair cells (OHCs) (approximately 1/2 the width of the BM) and 2) at the reticular lamina (RL) where the OHCs are located. We confirmed that electrical stimulation with a frequency sweep (12 kHz -25 kHz) caused a mechanical BM displacement with a peak and a traveling wave-like phase delay as we reported previously using laser Doppler velocimetry and reflective beads on the BM. Reflective beads were not used in the current study. The vibration of the RL had little or no phase delay that would characterize a traveling wave. These data suggest a very high compliance system for the electrically activated cellular structure of the organ.

  19. Electrical stimulation: a novel tool for tissue engineering.

    PubMed

    Balint, Richard; Cassidy, Nigel J; Cartmell, Sarah H

    2013-02-01

    New advances in tissue engineering are being made through the application of different types of electrical stimuli to influence cell proliferation and differentiation. Developments made in the last decade have allowed us to improve the structure and functionality of tissue-engineered products through the use of growth factors, hormones, drugs, physical stimuli, bioreactor use, and two-dimensional (2-D) and three-dimensional (3-D) artificial extracellular matrices (with various material properties and topography). Another potential type of stimulus is electricity, which is important in the physiology and development of the majority of all human tissues. Despite its great potential, its role in tissue regeneration and its ability to influence cell migration, orientation, proliferation, and differentiation has rarely been considered in tissue engineering. This review highlights the importance of endogenous electrical stimulation, gathering the current knowledge on its natural occurrence and role in vivo, discussing the novel methods of delivering this stimulus and examining its cellular and tissue level effects, while evaluating how the technique could benefit the tissue engineering discipline in the future.

  20. Evaluation of unintended electrical stimulation from MR gradient fields.

    PubMed

    Bassen, Howard I; Angelone, Leonardo M

    2012-01-01

    Exposure of patients with active implants (e.g. cardiac pacemakers and neurostimulators) to magnetic gradient fields (kHz range) during magnetic resonance imaging presents safety issues, such as unintended stimulation. Magnetically induced electric fields generate currents along the implant's lead, especially high at the distal tip. Experimental evaluation of the induced electric field was previously conducted. This study aimed to perform the same evaluation by means of computational methods, using two commercially available software packages (SemcadX and COMSOL Multiphysics). Electric field values were analyzed 1-3 mm from the distal tip. The effect of the two-electrode experimental probe was evaluated. The results were compared with previously published experimental data with reasonable agreement at locations more than 2-3 mm from the distal tip of the lead. The results were affected by the computational mesh size, with up to one order of magnitude difference for SEMCAD (resolution of 0.1 mm) compared to COMSOL (resolution of 0.5 mm). The results were also affected by the dimensions of the two-electrode probe, suggesting careful selection of the probe dimensions during experimental studies.

  1. Electrically conductive biodegradable polymer composite for nerve regeneration: electricity-stimulated neurite outgrowth and axon regeneration.

    PubMed

    Zhang, Ze; Rouabhia, Mahmoud; Wang, Zhaoxu; Roberge, Christophe; Shi, Guixin; Roche, Phillippe; Li, Jiangming; Dao, Lê H

    2007-01-01

    Normal and electrically stimulated PC12 cell cultures and the implantation of nerve guidance channels were performed to evaluate newly developed electrically conductive biodegradable polymer composites. Polypyrrole (PPy) doped by butane sulfonic acid showed a significantly higher number of viable cells compared with PPy doped by polystyrenesulfonate after a 6-day culture. The PC12 cells were left to proliferate for 6 days, and the PPy-coated membranes, showing less initial cell adherence, recorded the same proliferation rate as did the noncoated membranes. Direct current electricity at various intensities was applied to the PC12 cell-cultured conductive membranes. After 7 days, the greatest number of neurites appeared on the membranes with a current intensity approximating 1.7-8.4 microA/cm. Nerve guidance channels made of conductive biodegradable composite were implanted into rats to replace 8 mm of sciatic nerve. The implants were harvested after 2 months and analyzed with immunohistochemistry and transmission electron microscopy. The regenerated nerve tissue displayed myelinated axons and Schwann cells that were similar to those in the native nerve. Electrical stimulation applied through the electrically conductive biodegradable polymers therefore enhanced neurite outgrowth in a current-dependent fashion. The conductive polymers also supported sciatic nerve regeneration in rats.

  2. Spatiotemporal structure of intracranial electric fields induced by transcranial electric stimulation in humans and nonhuman primates.

    PubMed

    Opitz, Alexander; Falchier, Arnaud; Yan, Chao-Gan; Yeagle, Erin M; Linn, Gary S; Megevand, Pierre; Thielscher, Axel; Deborah A, Ross; Milham, Michael P; Mehta, Ashesh D; Schroeder, Charles E

    2016-08-18

    Transcranial electric stimulation (TES) is an emerging technique, developed to non-invasively modulate brain function. However, the spatiotemporal distribution of the intracranial electric fields induced by TES remains poorly understood. In particular, it is unclear how much current actually reaches the brain, and how it distributes across the brain. Lack of this basic information precludes a firm mechanistic understanding of TES effects. In this study we directly measure the spatial and temporal characteristics of the electric field generated by TES using stereotactic EEG (s-EEG) electrode arrays implanted in cebus monkeys and surgical epilepsy patients. We found a small frequency dependent decrease (10%) in magnitudes of TES induced potentials and negligible phase shifts over space. Electric field strengths were strongest in superficial brain regions with maximum values of about 0.5 mV/mm. Our results provide crucial information of the underlying biophysics in TES applications in humans and the optimization and design of TES stimulation protocols. In addition, our findings have broad implications concerning electric field propagation in non-invasive recording techniques such as EEG/MEG.

  3. Spatiotemporal structure of intracranial electric fields induced by transcranial electric stimulation in humans and nonhuman primates

    PubMed Central

    Opitz, Alexander; Falchier, Arnaud; Yan, Chao-Gan; Yeagle, Erin M.; Linn, Gary S.; Megevand, Pierre; Thielscher, Axel; Deborah A., Ross; Milham, Michael P.; Mehta, Ashesh D.; Schroeder, Charles E.

    2016-01-01

    Transcranial electric stimulation (TES) is an emerging technique, developed to non-invasively modulate brain function. However, the spatiotemporal distribution of the intracranial electric fields induced by TES remains poorly understood. In particular, it is unclear how much current actually reaches the brain, and how it distributes across the brain. Lack of this basic information precludes a firm mechanistic understanding of TES effects. In this study we directly measure the spatial and temporal characteristics of the electric field generated by TES using stereotactic EEG (s-EEG) electrode arrays implanted in cebus monkeys and surgical epilepsy patients. We found a small frequency dependent decrease (10%) in magnitudes of TES induced potentials and negligible phase shifts over space. Electric field strengths were strongest in superficial brain regions with maximum values of about 0.5 mV/mm. Our results provide crucial information of the underlying biophysics in TES applications in humans and the optimization and design of TES stimulation protocols. In addition, our findings have broad implications concerning electric field propagation in non-invasive recording techniques such as EEG/MEG. PMID:27535462

  4. A Gastrointestinal Electrical Stimulation System Based on Transcutaneous Power Transmission Technology

    PubMed Central

    Zhu, Bingquan; Wang, Yongbing; Yan, Guozheng; Jiang, Pingping; Liu, Zhiqiang

    2014-01-01

    Electrical stimulation has been suggested as a possible treatment for various functional gastrointestinal disorders (FGID). This paper presents a transcutaneous power supplied implantable electrical stimulation system. This technology solves the problem of supplying extended power to an implanted electrical stimulator. After implantation, the stimulation parameters can be reprogrammed by the external controller and then transmitted to the implanted stimulator. This would enable parametric studies to investigate the efficacy of various stimulation parameters in promoting gastrointestinal contractions. A pressure detector in the internal stimulator can provide real-time feedback about variations in the gastrointestinal tract. An optimal stimulation protocol leading to cecal contractions has been proposed: stimulation bursts of 3 ms pulse width, 10 V amplitude, 40 Hz frequency, and 20 s duration. The animal experiment demonstrated the functionality of the system and validated the effects of different stimulation parameters on cecal contractions. PMID:25053939

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. Patterns of primary afferent depolarization of segmental and ascending intraspinal collaterals of single joint afferents in the cat.

    PubMed

    Rudomin, P; Lomelí, J

    2007-01-01

    We have examined in the anesthetized cat the threshold changes produced by sensory and supraspinal stimuli on intraspinal collaterals of single afferents from the posterior articular nerve (PAN). Forty-eight fibers were tested in the L3 segment, in or close to Clarke's column, and 70 fibers in the L6-L7 segments within the intermediate zone. Of these, 15 pairs of L3 and L6-L7 collaterals were from the same afferent. Antidromically activated fibers had conduction velocities between 23 and 74 m/s and peripheral thresholds between 1.1 and 4.7 times the threshold of the most excitable fibers (xT), most of them below 3 xT. PAN afferents were strongly depolarized by stimulation of muscle afferents and by cutaneous afferents, as well as by stimulation of the bulbar reticular formation and the midline raphe nuclei. Stimulation of muscle nerves (posterior biceps and semitendinosus, quadriceps) produced a larger PAD (primary afferent depolarization) in the L6-L7 than in the L3 terminations. Group II were more effective than group I muscle afferents. As with group I muscle afferents, the PAD elicited in PAN afferents by stimulation of muscle nerves could be inhibited by conditioning stimulation of cutaneous afferents. Stimulation of the cutaneous sural and superficial peroneal nerves increased the threshold of few terminations (i.e., produced primary afferent hyperpolarization, PAH) and reduced the threshold of many others, particularly of those tested in the L6-L7 segments. Yet, there was a substantial number of terminals where these conditioning stimuli had minor or no effects. Autogenetic stimulation of the PAN with trains of pulses increased the intraspinal threshold in 46% and reduced the threshold in 26% of fibers tested in the L6-L7 segments (no tests were made with trains of pulses on fibers ending in L3). These observations indicate that PAN afferents have a rather small autogenetic PAD, particularly if this is compared with the effects of heterogenetic stimulation

  11. Electrical stimulation: Its role in growth, repair and remodeling of the musculoskeletal system

    SciTech Connect

    Black, J.

    1986-01-01

    This book examines the increasingly popular field of electrical stimulation of lesions of the musculoskeletal system, exploring its use in both research and treatment. The book describes clinical experience with electrical stimulation in orthopedic, neuro- and plastic surgery, biological sources of electrical signals, and electromechanical characterization of tissues. Contents include: growth; remodeling and repair; electricity and magnetism; electrical properties of tissues; natural electrical signals in the musculoskeletal system; methods for stimulating tissues; cell, tissue and organ culture; animal studies; clinical applications; overview and a glossary.

  12. 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.

  13. The influence of antagonist muscle electrical stimulation on maximal hip adduction force

    PubMed Central

    Nakano, Sota; Wada, Chikamune

    2016-01-01

    [Purpose] The aim of this study was to determine whether electrical stimulation of the tensor fascia lata muscle decreases voluntary maximum resistance to passive abduction motion in participants without disease of the central nervous system. [Subjects] The participants were 16 healthy men. [Methods] The hip joint was moved from 10° adduction to 0° adduction with an angular velocity of 7°/s. During the passive leg motion, the subject was asked to resist the motion with maximum force. Two experimental conditions were prepared: (1) electrical stimulation provided to the tensor fascia lata muscle during the passive motion; and (2) no electrical stimulation provided. [Results] The force was 10.2 ± 3.5 kgf with electrical stimulation and 12.2 ± 3.8 kgf without electrical stimulation. [Conclusion] The results suggested that the maximum hip adduction force decreased in participants because of electrical stimulation of the tensor fascia lata muscle. PMID:26957742

  14. A personal user's view of functional electrical stimulation cycling.

    PubMed

    Fitzwater, Roger

    2002-03-01

    Two years of functional electrical stimulation cycling (FESC) as a researcher and subject have given me an insight into the direction that future FESC should take as well as providing me with significant health benefits and an enjoyable and functional ability to cycle. If FESC is to benefit spinal cord injured persons (SCIPs), researchers must turn their attention to making the activity convenient and enjoyable. What follows is a personal view and will be less scientifically rigorous than other presentations but hopefully still of value. It calls upon my experience as a general medical practitioner with a special interest in the value of exercise, a human powered vehicle enthusiast, an amateur FES researcher, but most importantly, an SCIP and FES cyclist.

  15. Tuning face perception with electrical stimulation of the fusiform gyrus.

    PubMed

    Keller, Corey J; Davidesco, Ido; Megevand, Pierre; Lado, Fred A; Malach, Rafael; Mehta, Ashesh D

    2017-03-27

    The fusiform gyrus (FG) is an important node in the face processing network, but knowledge of its causal role in face perception is currently limited. Recent work demonstrated that high frequency stimulation applied to the FG distorts the perception of faces in human subjects (Parvizi et al. []: J Neurosci 32:14915-14920). However, the timing of this process in the FG relative to stimulus onset and the spatial extent of FG's role in face perception are unknown. Here, we investigate the causal role of the FG in face perception by applying precise, event-related electrical stimulation (ES) to higher order visual areas including the FG in six human subjects undergoing intracranial monitoring for epilepsy. We compared the effects of single brief (100 μs) electrical pulses to the FG and non-face-selective visual areas on the speed and accuracy of detecting distorted faces. Brief ES applied to face-selective sites did not affect accuracy but significantly increased the reaction time (RT) of detecting face distortions. Importantly, RT was altered only when ES was applied 100ms after visual onset and in face-selective but not place-selective sites. Furthermore, ES applied to face-selective areas decreased the amplitude of visual evoked potentials and high gamma power over this time window. Together, these results suggest that ES of face-selective regions within a critical time window induces a delay in face perception. These findings support a temporally and spatially specific causal role of face-selective areas and signify an important link between electrophysiology and behavior in face perception. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.

  16. Chronic Stress Decreases Cerebrovascular Responses During Rat Hindlimb Electrical Stimulation

    PubMed Central

    Lee, Sohee; Kang, Bok-Man; Shin, Min-Kyoo; Min, Jiwoong; Heo, Chaejeong; Lee, Yubu; Baeg, Eunha; Suh, Minah

    2015-01-01

    Repeated stress is one of the major risk factors for cerebrovascular disease, including stroke, and vascular dementia. However, the functional alterations in the cerebral hemodynamic response induced by chronic stress have not been clarified. Here, we investigated the in vivo cerebral hemodynamic changes and accompanying cellular and molecular changes in chronically stressed rats. After 3 weeks of restraint stress, the elicitation of stress was verified by behavioral despair in the forced swimming test and by physical indicators of stress. The evoked changes in the cerebral blood volume and pial artery responses following hindpaw electrical stimulation were measured using optical intrinsic signal imaging. We observed that, compared to the control group, animals under chronic restraint stress exhibited a decreased hemodynamic response, with a smaller pial arterial dilation in the somatosensory cortex during hindpaw electrical stimulation. The effect of chronic restraint stress on vasomodulator enzymes, including neuronal nitric oxide synthase (nNOS) and heme oxygenase-2 (HO-2), was assessed in the somatosensory cortex. Chronic restraint stress downregulated nNOS and HO-2 compared to the control group. In addition, we examined the subtypes of cells that can explain the environmental changes due to the decreased vasomodulators. The expression of parvalbumin in GABAergic interneurons and glutamate receptor-1 in neurons were decreased, whereas the microglial activation was increased. Our results suggest that the chronic stress-induced alterations in cerebral vascular function and the modulations of the cellular expression in the neuro-vasomodulatory system may be crucial contributing factors in the development of various vascular-induced conditions in the brain. PMID:26778944

  17. Neuronal pathways from foot pad afferents to hindlimb motoneurons in the low spinalized cats.

    PubMed

    Wada, N; Kanda, Y; Takayama, R

    1998-07-01

    Experiments were performed on 16 adult spinalized (L2) cats. Postsynaptic potentials (PSPs) produced by electrical stimulation of afferent nerves innervating foot pads were recorded from hindlimb motoneurons innervating the following hindlimb muscles: the posterior biceps and semitendinosus (PBSt), anterior biceps and semimembranosus (ABSm), lateral gastrocnemius and soleus (LGS), medial gastrocnemius (MG), plantaris (P1), tibialis anterior (TA), popliteus (Pop), flexor digitorum longus and flexor hallucis longus (FDHL) and peroneus longus (Per.l). The rate of occurrence of different types of PSPs (EPSPs, IPSPs and mixed PSPs), the size of the PSPs and their central latencies were analyzed for each group of motoneurons to identify the neural pathways from the afferents innervating foot pads to hindlimb motoneurons. The rates of occurrence of different types of PSPs did not depend on the foot pad stimulated in PBSt, ABSm and LGS motoneurons, but for other groups of motoneurons their rates of occurrence depended on the foot pad stimulated. It was often noted that the size of PSPs in the same motoneurons differed according to the foot pad stimulated. Measurements of the central latencies of the PSPs indicated that the shortest neural pathways for EPSPs and IPSPs were disynaptic (central latencies < 1.8 ms). The functional role of neuronal pathways from afferent nerves innervating foot pads to hindlimb motoneurons could be to maintain stability of the foot during different postural and motor activities.

  18. Highly Flexible Silicone Coated Neural Array for Intracochlear Electrical Stimulation

    PubMed Central

    Bhatti, P.; Van Beek-King, J.; Sharpe, A.; Crawford, J.; Tridandapani, S.; McKinnon, B.; Blake, D.

    2015-01-01

    We present an effective method for tailoring the flexibility of a commercial thin-film polymer electrode array for intracochlear electrical stimulation. Using a pneumatically driven dispensing system, an average 232 ± 64 μm (mean ± SD) thickness layer of silicone adhesive coating was applied to stiffen the underside of polyimide multisite arrays. Additional silicone was applied to the tip to protect neural tissue during insertion and along the array to improve surgical handling. Each array supported 20 platinum sites (180 μm dia., 250 μm pitch), spanning nearly 28 mm in length and 400 μm in width. We report an average intracochlear stimulating current threshold of 170 ± 93 μA to evoke an auditory brainstem response in 7 acutely deafened felines. A total of 10 arrays were each inserted through a round window approach into the cochlea's basal turn of eight felines with one delamination occurring upon insertion (preliminary results of the in vivo data presented at the 48th Annual Meeting American Neurotology Society, Orlando, FL, April 2013, and reported in Van Beek-King 2014). Using microcomputed tomography imaging (50 μm resolution), distances ranging from 100 to 565 μm from the cochlea's central modiolus were measured. Our method combines the utility of readily available commercial devices with a straightforward postprocessing step on the order of 24 hours. PMID:26236714

  19. Individual differences in transcranial electrical stimulation current density

    PubMed Central

    Russell, Michael J; Goodman, Theodore; Pierson, Ronald; Shepherd, Shane; Wang, Qiang; Groshong, Bennett; Wiley, David F

    2013-01-01

    Transcranial electrical stimulation (TCES) is effective in treating many conditions, but it has not been possible to accurately forecast current density within the complex anatomy of a given subject's head. We sought to predict and verify TCES current densities and determine the variability of these current distributions in patient-specific models based on magnetic resonance imaging (MRI) data. Two experiments were performed. The first experiment estimated conductivity from MRIs and compared the current density results against actual measurements from the scalp surface of 3 subjects. In the second experiment, virtual electrodes were placed on the scalps of 18 subjects to model simulated current densities with 2 mA of virtually applied stimulation. This procedure was repeated for 4 electrode locations. Current densities were then calculated for 75 brain regions. Comparison of modeled and measured external current in experiment 1 yielded a correlation of r = .93. In experiment 2, modeled individual differences were greatest near the electrodes (ten-fold differences were common), but simulated current was found in all regions of the brain. Sites that were distant from the electrodes (e.g. hypothalamus) typically showed two-fold individual differences. MRI-based modeling can effectively predict current densities in individual brains. Significant variation occurs between subjects with the same applied electrode configuration. Individualized MRI-based modeling should be considered in place of the 10-20 system when accurate TCES is needed. PMID:24285948

  20. The value of electrical stimulation as an exercise training modality

    NASA Technical Reports Server (NTRS)

    Currier, Dean P.; Ray, J. Michael; Nyland, John; Noteboom, Tim

    1994-01-01

    Voluntary exercise is the traditional way of improving performance of the human body in both the healthy and unhealthy states. Physiological responses to voluntary exercise are well documented. It benefits the functions of bone, joints, connective tissue, and muscle. In recent years, research has shown that neuromuscular electrical stimulation (NMES) simulates voluntary exercise in many ways. Generically, NMES can perform three major functions: suppression of pain, improve healing of soft tissues, and produce muscle contractions. Low frequency NMES may gate or disrupt the sensory input to the central nervous system which results in masking or control of pain. At the same time NMES may contribute to the activation of endorphins, serotonin, vasoactive intestinal polypeptides, and ACTH which control pain and may even cause improved athletic performances. Soft tissue conditions such as wounds and inflammations have responded very favorably to NMES. NMES of various amplitudes can induce muscle contractions ranging from weak to intense levels. NMES seems to have made its greatest gains in rehabilitation where directed muscle contractions may improve joint ranges of motion correct joint contractures that result from shortening muscles; control abnormal movements through facilitating recruitment or excitation into the alpha motoneuron in orthopedically, neurologically, or healthy subjects with intense sensory, kinesthetic, and proprioceptive information; provide a conservative approach to management of spasticity in neurological patients; by stimulation of the antagonist muscle to a spastic muscle stimulation of the agonist muscle, and sensory habituation; serve as an orthotic substitute to conventional bracing used with stroke patients in lieu of dorsiflexor muscles in preventing step page gait and for shoulder muscles to maintain glenohumeral alignment to prevent subluxation; and of course NMES is used in maintaining or improving the performance or torque producing

  1. Inhibition of stimulated dopamine release and hemodynamic response in the brain through electrical stimulation of rat forepaw.

    PubMed Central

    Chen, Y Iris; Ren, Jiaqian; Wang, Fu-Nien; Xu, Haibo; Mandeville, Joseph B; Kim, Young; Rosen, Bruce R; Jenkins, Bruce G; Hui, Kathleen KS; Kwong, Kenneth K

    2008-01-01

    The subcortical response to peripheral somatosensory stimulation is not well studied. Prior literature suggests that somatosensory stimulation can affect dopaminergic tone. We studied the effects of electrical stimulation near the median nerve on the response to an amphetamine induced increase in synaptic dopamine. We applied the electrical stimulation close to the median nerve 20 minutes after administration of 3mg/kg amphetamine. We used fMRI and microdialysis to measure markers of DA release, together with the release of associated neurotransmitters of striatal Glutamate (Glu) and GABA. Result 1) Changes in cerebral blood volume (CBV), a marker used in fMRI, indicate that electrical stimulation significantly attenuated increased DA release (due to AMPH) in the striatum, thalamus, medial prefrontal and cingulate cortices. 2) Microdialysis showed that electrical stimulation increased Glu and GABA release and attenuated the AMPH-enhanced DA release. The striatal DA dynamics correlated with the CBV response. Conclusion These results demonstrate that electrical stimulation near the median nerve activates Glu/GABA release which subsequently attenuate excess striatal DA release. These data provide evidence for physiologic modulation caused by electroacupuncture at points near the median nerve. PMID:18178315

  2. Numerical simulation of electrically stimulated osteogenesis in dental implants.

    PubMed

    Vanegas-Acosta, J C; Garzón-Alvarado, D A; Lancellotti, V

    2014-04-01

    Cell behavior and tissue formation are influenced by a static electric field (EF). Several protocols for EF exposure are aimed at increasing the rate of tissue recovery and reducing the healing times in wounds. However, the underlying mechanisms of the EF action on cells and tissues are still a matter of research. In this work we introduce a mathematical model for electrically stimulated osteogenesis at the bone-dental implant interface. The model describes the influence of the EF in the most critical biological processes leading to bone formation at the bone-dental implant interface. The numerical solution is able to reproduce the distribution of spatial-temporal patterns describing the influence of EF during blood clotting, osteogenic cell migration, granulation tissue formation, displacements of the fibrillar matrix, and formation of new bone. In addition, the model describes the EF-mediated cell behavior and tissue formation which lead to an increased osteogenesis in both smooth and rough implant surfaces. Since numerical results compare favorably with experimental evidence, the model can be used to predict the outcome of using electrostimulation in other types of wounds and tissues.

  3. No Influence of Transcutaneous Electrical Nerve Stimulation on Exercise-Induced Pain and 5-Km Cycling Time-Trial Performance

    PubMed Central

    Hibbert, Andrew W.; Billaut, François; Varley, Matthew C.; Polman, Remco C. J.

    2017-01-01

    Introduction: Afferent information from exercising muscle contributes to the sensation of exercise-induced muscle pain. Transcutaneous electrical nerve stimulation (TENS) delivers low–voltage electrical currents to the skin, inhibiting nociceptive afferent information. The use of TENS in reducing perceptions of exercise-induced pain has not yet been fully explored. This study aimed to investigate the effect of TENS on exercise-induced muscle pain, pacing strategy, and performance during a 5-km cycling time trial (TT). Methods: On three separate occasions, in a single-blind, randomized, and cross-over design, 13 recreationally active participants underwent a 30-min TENS protocol, before performing a 5-km cycling TT. TENS was applied to the quadriceps prior to exercise under the following conditions; control (CONT), placebo with sham TENS application (PLAC), and an experimental condition with TENS application (TENS). Quadriceps fatigue was assessed with magnetic femoral nerve stimulation assessing changes in potentiated quadriceps twitch force at baseline, pre and post exercise. Subjective scores of exertion, affect and pain were taken every 1-km. Results: During TTs, application of TENS did not influence pain perceptions (P = 0.68, ηp2 = 0.03). There was no significant change in mean power (P = 0.16, ηp2 = 0.16) or TT duration (P = 0.17, ηp2 = 0.14), although effect sizes were large for these two variables. Changes in power output were not significant but showed moderate effect sizes at 500-m (ηp2 = 0.10) and 750-m (ηp2 = 0.10). Muscle recruitment as inferred by electromyography data was not significant, but showed large effect sizes at 250-m (ηp2 = 0.16), 500-m (ηp2 = 0.15), and 750-m (ηp2 = 0.14). This indicates a possible effect for TENS influencing performance up to 1-km. Discussion: These findings do not support the use of TENS to improve 5-km TT performance. PMID:28223939

  4. No Influence of Transcutaneous Electrical Nerve Stimulation on Exercise-Induced Pain and 5-Km Cycling Time-Trial Performance.

    PubMed

    Hibbert, Andrew W; Billaut, François; Varley, Matthew C; Polman, Remco C J

    2017-01-01

    Introduction: Afferent information from exercising muscle contributes to the sensation of exercise-induced muscle pain. Transcutaneous electrical nerve stimulation (TENS) delivers low-voltage electrical currents to the skin, inhibiting nociceptive afferent information. The use of TENS in reducing perceptions of exercise-induced pain has not yet been fully explored. This study aimed to investigate the effect of TENS on exercise-induced muscle pain, pacing strategy, and performance during a 5-km cycling time trial (TT). Methods: On three separate occasions, in a single-blind, randomized, and cross-over design, 13 recreationally active participants underwent a 30-min TENS protocol, before performing a 5-km cycling TT. TENS was applied to the quadriceps prior to exercise under the following conditions; control (CONT), placebo with sham TENS application (PLAC), and an experimental condition with TENS application (TENS). Quadriceps fatigue was assessed with magnetic femoral nerve stimulation assessing changes in potentiated quadriceps twitch force at baseline, pre and post exercise. Subjective scores of exertion, affect and pain were taken every 1-km. Results: During TTs, application of TENS did not influence pain perceptions (P = 0.68, [Formula: see text] = 0.03). There was no significant change in mean power (P = 0.16, [Formula: see text] = 0.16) or TT duration (P = 0.17, [Formula: see text] = 0.14), although effect sizes were large for these two variables. Changes in power output were not significant but showed moderate effect sizes at 500-m ([Formula: see text] = 0.10) and 750-m ([Formula: see text] = 0.10). Muscle recruitment as inferred by electromyography data was not significant, but showed large effect sizes at 250-m ([Formula: see text] = 0.16), 500-m ([Formula: see text] = 0.15), and 750-m ([Formula: see text] = 0.14). This indicates a possible effect for TENS influencing performance up to 1-km. Discussion: These findings do not support the use of TENS to

  5. Static γ-motoneurones couple group Ia and II afferents of single muscle spindles in anaesthetised and decerebrate cats

    PubMed Central

    Gladden, M H; Matsuzaki, H

    2002-01-01

    Ideas about the functions of static γ-motoneurones are based on the responses of primary and secondary endings to electrical stimulation of single static γ-axons, usually at high frequencies. We compared these effects with the actions of spontaneously active γ-motoneurones. In anaesthetised cats, afferents and efferents were recorded in intramuscular nerve branches to single muscle spindles. The occurrence of γ-spikes, identified by a spike shape recognition system, was linked to video-taped contractions of type-identified intrafusal fibres in the dissected muscle spindles. When some static γ-motoneurones were active at low frequency (< 15 Hz) they coupled the firing of group Ia and II afferents. Activity of other static γ-motoneurones which tensed the intrafusal fibres appeared to enhance this effect. Under these conditions the secondary ending responded at shorter latency than the primary ending. In another series of experiments on decerebrate cats, responses of primary and secondary endings of single muscle spindles to activation of γ-motoneurones by natural stimuli were compared with their responses to electrical stimulation of single γ-axons supplying the same spindle. Electrical stimulation mimicked the natural actions of γ-motoneurones on either the primary or the secondary ending, but not on both together. However, γ-activity evoked by natural stimuli coupled the firing of afferents with the muscle at constant length, and also when it was stretched. Analysis showed that the timing and tightness of this coupling determined the degree of summation of excitatory postsynaptic potentials (EPSPs) evoked by each afferent in α-motoneurones and interneurones contacted by terminals of both endings, and thus the degree of facilitation of reflex actions of group II afferents. PMID:12181298

  6. Electrical stimulation (ES) in the management of sexual pain disorders.

    PubMed

    Nappi, Rossella E; Ferdeghini, Francesea; Abbiati, Ileana; Vercesi, Claudia; Farina, Claudio; Polatti, Franco

    2003-01-01

    We performed an open study to investigate the use of electrical stimulation (ES) on the vestibular area and vaginal introitus in women with sexual pain disorders. We recruited 29 women (age range 20-45 years) from among the patients at our Reproductive Psychobiology Unit to participate in the present study. They each experienced vestibular pain, inducing dyspareunia and vaginism. We performed ES with an ECL43400 apparatus (Elite, EssediEsse srl, Milan, Italy) once a week for 10 weeks. To evaluate the muscular activity of the perineal floor and sexual function, we employed the same apparatus with a vaginal probe for recording myoelectrical activity (muV), we employed a VAS scale for evaluating pain, and we administered the Female Sexual Function Index (FSFI; Rosen et al., 2000) before and after the study protocol. We analyzed data by parametric and nonparametric comparisons and correlations, as appropriate. Our major findings were as follows: (a) the contractile ability of pelvic floor muscles (p < 0.001), as well as the resting ability (p < 0.001), significantly improved following ES; (b) the current intensity tolerated significantly increased (p < 0.001) throughout the study, from 41.3 +/- 7.4 mA at the start of the study to 50 +/- 7.4 mA at the end of the stimulation protocol; (c) the Visual Analogic Scale (VAS) for pain significantly declined (p < 0.001), whereas FSFI pain scores (p < 0.001) and full scale scores (p < 0.001) significantly improved following ES, and 4 out of 9 women with vaginism went back to coital activity; (d) FSFI pain score and the current intensity tolerated, both before (R = .59; p < 0.006) and at the end (R = .53; p < 0.02) of the stimulation protocol, positively correlated. ES may be effective in the management of sexual pain disorders. Further controlled studies are necessary to standardize stimulation protocols according to the severity of pain and to better clarify the long-term clinical effects of ES.

  7. Short trains of intra-epidermal electrical stimulation to elicit reliable behavioral and electrophysiological responses to the selective activation of nociceptors in humans.

    PubMed

    Mouraux, André; Marot, Emilie; Legrain, Valéry

    2014-02-21

    Currently, the study of nociception in humans relies mainly on thermal stimulation of heat-sensitive nociceptive afferents. To circumvent some limitations of thermal stimulation, it was proposed that intra-epidermal electrical stimulation (IES) could be used as an alternative method to activate nociceptors selectively. The selectivity of IES relies on the fact that it can generate a very focal electrical current and, thereby, activate nociceptive free nerve endings located in the epidermis without concomitantly activating non-nociceptive mechanoreceptors located more deeply in the dermis. However, an important limitation of IES is that it is selective for nociceptors only when very low current intensities are used. At these intensities, the stimulus generates a very weak percept, and the signal-to-noise ratio of the elicited evoked potentials (EPs) is very low. To circumvent this limitation, it was proposed that the strength of the nociceptive afferent volley could be increased through temporal summation, using short trains of repeated IES. Here, we characterized the intensity of perception and EPs elicited by trains of 2, 3 and 4 IES delivered using a 5-ms inter-stimulus interval. We found that both the intensity of perception and the magnitude of EPs significantly increased with the number of pulses. In contrast, the latency of the elicited EPs was not affected by the number of pulses, indicating that temporal summation did not affect the type of activated fibers and, therefore, that trains of IES can be used to increase the reliability of stimulus-evoked responses while still preserving its selectivity for nociceptors.

  8. Effects of a multichannel dynamic functional electrical stimulation system on hemiplegic gait and muscle forces

    PubMed Central

    Qian, Jing-guang; Rong, Ke; Qian, Zhenyun; Wen, Chen; Zhang, Songning

    2015-01-01

    [Purpose] The purpose of the study was to design and implement a multichannel dynamic functional electrical stimulation system and investigate acute effects of functional electrical stimulation of the tibialis anterior and rectus femoris on ankle and knee sagittal-plane kinematics and related muscle forces of hemiplegic gait. [Subjects and Methods] A multichannel dynamic electrical stimulation system was developed with 8-channel low frequency current generators. Eight male hemiplegic patients were trained for 4 weeks with electric stimulation of the tibia anterior and rectus femoris muscles during walking, which was coupled with active contraction. Kinematic data were collected, and muscle forces of the tibialis anterior and rectus femoris of the affected limbs were analyzed using a musculoskelatal modeling approach before and after training. A paired sample t-test was used to detect the differences between before and after training. [Results] The step length of the affected limb significantly increased after the stimulation was applied. The maximum dorsiflexion angle and maximum knee flexion angle of the affected limb were both increased significantly during stimulation. The maximum muscle forces of both the tibia anterior and rectus femoris increased significantly during stimulation compared with before functional electrical stimulation was applied. [Conclusion] This study established a functional electrical stimulation strategy based on hemiplegic gait analysis and musculoskeletal modeling. The multichannel functional electrical stimulation system successfully corrected foot drop and altered circumduction hemiplegic gait pattern. PMID:26696734

  9. Muscle motor point identification is essential for optimizing neuromuscular electrical stimulation use.

    PubMed

    Gobbo, Massimiliano; Maffiuletti, Nicola A; Orizio, Claudio; Minetto, Marco A

    2014-02-25

    Transcutaneous neuromuscular electrical stimulation applied in clinical settings is currently characterized by a wide heterogeneity of stimulation protocols and modalities. Practitioners usually refer to anatomic charts (often provided with the user manuals of commercially available stimulators) for electrode positioning, which may lead to inconsistent outcomes, poor tolerance by the patients, and adverse reactions. Recent evidence has highlighted the crucial importance of stimulating over the muscle motor points to improve the effectiveness of neuromuscular electrical stimulation. Nevertheless, the correct electrophysiological definition of muscle motor point and its practical significance are not always fully comprehended by therapists and researchers in the field. The commentary describes a straightforward and quick electrophysiological procedure for muscle motor point identification. It consists in muscle surface mapping by using a stimulation pen-electrode and it is aimed at identifying the skin area above the muscle where the motor threshold is the lowest for a given electrical input, that is the skin area most responsive to electrical stimulation. After the motor point mapping procedure, a proper placement of the stimulation electrode(s) allows neuromuscular electrical stimulation to maximize the evoked tension, while minimizing the dose of the injected current and the level of discomfort. If routinely applied, we expect this procedure to improve both stimulation effectiveness and patient adherence to the treatment.The aims of this clinical commentary are to present an optimized procedure for the application of neuromuscular electrical stimulation and to highlight the clinical implications related to its use.

  10. Selective cortical and segmental control of primary afferent depolarization of single muscle afferents in the cat spinal cord.

    PubMed

    Eguibar, J R; Quevedo, J; Rudomin, P

    1997-03-01

    This study was primarily aimed at investigating the selectivity of the cortico-spinal actions exerted on the pathways mediating primary afferent depolarization (PAD) of muscle spindle and tendon organ afferents ending within the intermediate nucleus at the L6-L7 segmental level. To this end we analyzed, in the anesthetized cat, the effects produced by electrical stimulation of sensory nerves and of the cerebral cortex on (a) the intraspinal threshold of pairs of single group I afferent fibers belonging to the same or to different hindlimb muscles and (b) the intraspinal threshold of two collaterals of the same muscle afferent fiber. Afferent fibers were classified in three categories, according to the effects produced by stimulation of segmental nerves and of the cerebral cortex. Twenty-five of 40 fibers (62.5%) were depolarized by stimulation of group I posterior biceps and semitendinosus (PBSt) or tibialis (Tib) fibers, but not by stimulation of the cerebral cortex or of cutaneous and joint nerves, which instead inhibited the PBSt- or Tib-induced PAD (type A PAD pattern, usually seen in Ia fibers). The remaining 15 fibers (37.5%) were all depolarized by stimulation of the PBSt or Tib nerves and the cerebral cortex. Stimulation of cutaneous and joint nerves produced PAD in 10 of those 15 fibers (type B PAD pattern) and inhibited the PBSt- or Tib-induced PAD in the 5 remaining fibers (type C PAD pattern). Fibers with a type B or C PAD pattern are likely to be Ib. Not all sites in the cerebral cortex inhibited with the same effectiveness the segmentally induced PAD of group I fibers with a type A PAD pattern. With the weakest stimulation of the cortical surface, the most effective sites that inhibited the PAD of individual fibers were surrounded by less effective sites, scattered all along the motor cortex (area 4gamma and 6) and sensory cortex (areas 3, 2 and 1), far beyond the area of projection of group I fibers from the hindlimb. With higher strengths of

  11. Spatial changes in the transmembrane potential during extracellular electric stimulation.

    PubMed

    Zhou, X; Knisley, S B; Smith, W M; Rollins, D; Pollard, A E; Ideker, R E

    1998-11-16

    The purpose of this study was to determine the spatial changes in the transmembrane potential caused by extracellular electric field stimulation. The transmembrane potential was recorded in 10 guinea pig papillary muscles in a tissue bath using a double-barrel microelectrode. After 20 S1 stimuli, a 10-ms square wave S2 shock field with a 30-ms S1-S2 coupling interval was given via patch shock electrodes 1 cm on either side of the tissue during the action potential plateau. Two shock strengths (2.1+/-0.2 and 6.5+/-0.6 V/cm) were tested with both shock polarities. The recording site was moved across the tissue along fibers with either 200 micrometer (macroscopic group [n=5], 12 consecutive recording sites over a 2. 2-mm tissue length in each muscle) or 20 micrometer (microscopic group [n=5], 21 consecutive recording sites over a 0.4-mm tissue length in each muscle) between adjacent recording sites. In the macroscopic group, the portion of the tissue toward the anode was hyperpolarized, whereas the portion toward the cathode was depolarized, with 1 zero-potential crossing from hyperpolarization to depolarization present near the center of the tissue. In the microscopic group, only 1 zero-potential crossing was observed in the center region of the tissue, whereas, away from the center, only hyperpolarization was observed toward the anode and depolarization toward the cathode. Although these results are consistent with predictions from field stimulation of continuous representations of myocardial structure, ie, the bidomain and cable equation models, they are not consistent with the prediction of depolarization-hyperpolarization oscillation from representations based on cellular-level resistive discontinuities associated with gap junctions, ie, the sawtooth model.

  12. Electric Field Model of Transcranial Electric Stimulation in Nonhuman Primates: Correspondence to Individual Motor Threshold

    PubMed Central

    Lee, Won Hee; Lisanby, Sarah H.; Laine, Andrew F.

    2015-01-01

    Objective To develop a pipeline for realistic head models of nonhuman primates (NHPs) for simulations of noninvasive brain stimulation, and use these models together with empirical threshold measurements to demonstrate that the models capture individual anatomical variability. Methods Based on structural MRI data, we created models of the electric field (E-field) induced by right unilateral (RUL) electroconvulsive therapy (ECT) in four rhesus macaques. Individual motor threshold (MT) was measured with transcranial electric stimulation (TES) administered through the RUL electrodes in the same subjects. Results The interindividual anatomical differences resulted in 57% variation in median E-field strength in the brain at fixed stimulus current amplitude. Individualization of the stimulus current by MT reduced the E-field variation in the target motor area by 27%. There was significant correlation between the measured MT and the ratio of simulated electrode current and E-field strength (r2 = 0.95, p = 0.026). Exploratory analysis revealed significant correlations of this ratio with anatomical parameters including of the superior electrode-to-cortex distance, vertex-to-cortex distance, and brain volume (r2 > 0.96, p < 0.02). The neural activation threshold was estimated to be 0.45 ± 0.07 V/cm for 0.2 ms stimulus pulse width. Conclusion These results suggest that our individual-specific NHP E-field models appropriately capture individual anatomical variability relevant to the dosing of TES/ECT. These findings are exploratory due to the small number of subjects. Significance This work can contribute insight in NHP studies of ECT and other brain stimulation interventions, help link the results to clinical studies, and ultimately lead to more rational brain stimulation dosing paradigms. PMID:25910001

  13. Rescue of neuronal function by cross-regeneration of cutaneous afferents into muscle in cats.

    PubMed

    Nishimura, H; Johnson, R D; Munson, J B

    1993-07-01

    1. This study investigates the relation between the peripheral innervation of low-threshold cutaneous afferents and the postsynaptic potentials elicited by electrical stimulation of those afferents. 2. In cats deeply anesthetized with pentobarbital sodium, cord dorsum potentials (CDPs) and postsynaptic potentials (PSPs) in spinal motoneurons were elicited by stimulation of the caudal cutaneous sural nerve (CCS), the lateral cutaneous sural nerve (LCS), and the medial gastrocnemius (MG) muscle nerve. We tested 1) unoperated cats, and cats in which CCS has been 2) chronically axotomized and ligated, 3) cut and self-reunited, 4) cut and cross-united with LCS, or 5) cut and cross-united with the MG. Terminal experiments were performed 3-36 mo after initial surgery. 3. In cats in which the CCS had been self-reunited or cross-united distally with LCS, tactile stimulation of the hairy skin normally innervated by the distal nerve activated afferents in the CCS central to the coaptation, indicating that former CCS afferents had regenerated into native or foreign skin, respectively. 4. In cats in which the CCS had been cross-united distally with the MG, both stretch and contraction of the MG muscle activated the former CCS afferents. 5. In unoperated cats, CDPs elicited by stimulation of CCS and of LCS exhibited a low-threshold N1 wave and a higher-threshold N2 wave. These waves were greatly delayed and appeared to merge after chronic axotomy of CCS. Regeneration of CCS into itself, into LCS, or into MG restored the normal latencies and configurations of these potentials. 6. In unoperated cats, stimulation of CCS, of LCS, and of MG each produced PSPs of characteristic configurations in the various subpopulations of motoneurons of the triceps surae. CDPs and PSPs elicited by the CCS cross-regenerated into LCS or MG were typical of those generated by the normal CCS, i.e., there was no evidence of respecification of central synaptic connections to bring accord between center

  14. Electrical stimulation for the treatment of lower urinary tract dysfunction after spinal cord injury

    PubMed Central

    McGee, Meredith J.; Amundsen, Cindy L.; Grill, Warren M.

    2015-01-01

    Electrical stimulation for bladder control is an alternative to traditional methods of treating neurogenic lower urinary tract dysfunction (NLUTD) resulting from spinal cord injury (SCI). In this review, we systematically discuss the neurophysiology of bladder dysfunction following SCI and the applications of electrical stimulation for bladder control following SCI, spanning from historic clinical approaches to recent pre-clinical studies that offer promising new strategies that may improve the feasibility and success of electrical stimulation therapy in patients with SCI. Electrical stimulation provides a unique opportunity to control bladder function by exploiting neural control mechanisms. Our understanding of the applications and limitations of electrical stimulation for bladder control has improved due to many pre-clinical studies performed in animals and translational clinical studies. Techniques that have emerged as possible opportunities to control bladder function include pudendal nerve stimulation and novel methods of stimulation, such as high frequency nerve block. Further development of novel applications of electrical stimulation will drive progress towards effective therapy for SCI. The optimal solution for restoration of bladder control may encompass a combination of efficient, targeted electrical stimulation, possibly at multiple locations, and pharmacological treatment to enhance symptom control. PMID:25582564

  15. Tinnitus Treatment with Precise and Optimal Electric Stimulation: Opportunities and Challenges

    PubMed Central

    Zeng, Fan-Gang; Djalilian, Hamid; Lin, Harrison

    2015-01-01

    Purpose of review Electric stimulation is a potent means of neuromodulation that has been used to restore hearing and minimize tremor, but its application on tinnitus symptoms has been limited. We examine recent evidence to identify the knowledge gaps in the use of electric stimulation for tinnitus treatment. Recent findings Recent studies using electric stimulation to suppress tinnitus in humans are categorized according to their points of attacks. First, non-invasive, direct-current stimulation uses an active electrode in the ear canal, tympanic membrane or temporal scalp. Second, inner ear stimulation uses charge-balanced biphasic stimulation by placing an active electrode on the promontory or round window, or a cochlear implant array in the cochlea. Third, intraneural implants can provide targeted stimulation of specific sites along the auditory pathway. Although these studies demonstrated some success in tinnitus suppression, none established a link between tinnitus suppression efficacy and tinnitus-generating mechanisms. Summary Electric stimulation provides a unique opportunity to suppress tinnitus. Challenges include matching electric stimulation sites and patterns to tinnitus locus and type, meeting the oftentimes-contradictory demands between tinnitus suppression and other indications, such as speech understanding, and justifying the costs and risks of electric stimulation for tinnitus symptoms. PMID:26208122

  16. Vagal afferent activation decreases brown adipose tissue (BAT) sympathetic nerve activity and BAT thermogenesis

    PubMed Central

    Madden, Christopher J.; Santos da Conceicao, Ellen Paula; Morrison, Shaun F.

    2017-01-01

    ABSTRACT In urethane/α-chloralose anesthetized rats, electrical stimulation of cervical vagal afferent fibers inhibited the increases in brown adipose tissue sympathetic nerve activity and brown adipose tissue thermogenesis evoked by cold exposure, by nanoinjection of the GABAA receptor antagonist, bicuculline, in the dorsomedial hypothalamus, and by nanoinjection of N-methyl-D-aspartate in the rostral raphe pallidus. Vagus nerve stimulation-evoked inhibition of brown adipose tissue sympathetic nerve activity was prevented by blockade of ionotropic glutamate receptors in the termination site of vagal afferents in the nucleus of the solitary tract, and by nanoinjection of GABAA receptor antagonists in the rostral raphe pallidus. In conclusion, the brown adipose tissue sympathoinhibitory effect of cervical afferent vagal nerve stimulation is mediated by glutamatergic activation of second-order sensory neurons in the nucleus of the solitary tract and by a GABAergic inhibition of brown adipose tissue sympathetic premotor neurons in the rostral raphe pallidus, but does not require GABAergic inhibition of the brown adipose tissue sympathoexcitatory neurons in the dorsomedial hypothalamus. PMID:28349097

  17. Electrical Stimulation Promotes Cardiac Differentiation of Human Induced Pluripotent Stem Cells

    PubMed Central

    Hernández, Damián; Millard, Rodney; Sivakumaran, Priyadharshini; Wong, Raymond C. B.; Crombie, Duncan E.; Hewitt, Alex W.; Liang, Helena; Hung, Sandy S. C.; Pébay, Alice; Shepherd, Robert K.; Dusting, Gregory J.; Lim, Shiang Y.

    2016-01-01

    Background. Human induced pluripotent stem cells (iPSCs) are an attractive source of cardiomyocytes for cardiac repair and regeneration. In this study, we aim to determine whether acute electrical stimulation of human iPSCs can promote their differentiation to cardiomyocytes. Methods. Human iPSCs were differentiated to cardiac cells by forming embryoid bodies (EBs) for 5 days. EBs were then subjected to brief electrical stimulation and plated down for 14 days. Results. In iPS(Foreskin)-2 cell line, brief electrical stimulation at 65 mV/mm or 200 mV/mm for 5 min significantly increased the percentage of beating EBs present by day 14 after plating. Acute electrical stimulation also significantly increased the cardiac gene expression of ACTC1, TNNT2, MYH7, and MYL7. However, the cardiogenic effect of electrical stimulation was not reproducible in another iPS cell line, CERA007c6. Beating EBs from control and electrically stimulated groups expressed various cardiac-specific transcription factors and contractile muscle markers. Beating EBs were also shown to cycle calcium and were responsive to the chronotropic agents, isoproterenol and carbamylcholine, in a concentration-dependent manner. Conclusions. Our results demonstrate that brief electrical stimulation can promote cardiac differentiation of human iPS cells. The cardiogenic effect of brief electrical stimulation is dependent on the cell line used. PMID:26788064

  18. 9 CFR 307.7 - Safety requirements for electrical stimulating (EST) equipment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Safety requirements for electrical stimulating (EST) equipment. 307.7 Section 307.7 Animals and Animal Products FOOD SAFETY AND INSPECTION.../or slaughter animals or to facilitate hide removal. Electrical stimulating equipment consists of...

  19. Electrical Stimulation of Low-Threshold Proprioceptive Fibers in the Adult Rat Increases Density of Glutamatergic and Cholinergic Terminals on Ankle Extensor α-Motoneurons

    PubMed Central

    Gajewska-Woźniak, Olga; Grycz, Kamil; Czarkowska-Bauch, Julita; Skup, Małgorzata

    2016-01-01

    The effects of stimulation of low-threshold proprioceptive afferents in the tibial nerve on two types of excitatory inputs to α-motoneurons were tested. The first input is formed by glutamatergic Ia sensory afferents contacting monosynaptically α-motoneurons. The second one is the cholinergic input originating from V0c—interneurons, located in lamina X of the spinal cord, modulating activity of α-motoneurons via C-terminals. Our aim was to clarify whether enhancement of signaling to ankle extensor α-motoneurons, via direct electrical stimulation addressed predominantly to low-threshold proprioceptive fibers in the tibial nerve of awake rats, will affect Ia glutamatergic and cholinergic innervation of α-motoneurons of lateral gastrocnemius (LG). LG motoneurons were identified with True Blue tracer injected intramuscularly. Tibial nerve was stimulated for 7 days with continuous bursts of three pulses applied in four 20 min sessions daily. The Hoffmann reflex and motor responses recorded from the soleus muscle, LG synergist, allowed controlling stimulation. Ia terminals and C-terminals abutting on LG-labeled α-motoneurons were detected by immunofluorescence (IF) using input-specific anti- VGLUT1 and anti-VAChT antibodies, respectively. Quantitative analysis of confocal images revealed that the number of VGLUT1 IF and VAChT IF terminals contacting the soma of LG α-motoneurons increased after stimulation by 35% and by 26%, respectively, comparing to the sham-stimulated side. The aggregate volume of VGLUT1 IF and VAChT IF terminals increased by 35% and by 30%, respectively. Labeling intensity of boutons was also increased, suggesting an increase of signaling to LG α-motoneurons after stimulation. To conclude, one week of continuous burst stimulation of proprioceptive input to LG α-motoneurons is effective in enrichment of their direct glutamatergic but also indirect cholinergic inputs. The effectiveness of such and longer stimulation in models of injury is a

  20. Afferent and efferent activity control in the design of brain computer interfaces for motor rehabilitation.

    PubMed

    Cho, Woosang; Vidaurre, Carmen; Hoffmann, Ulrich; Birbaumer, Niels; Ramos-Murguialday, Ander

    2011-01-01

    Stroke is a cardiovascular accident within the brain resulting in motor and sensory impairment in most of the survivors. A stroke can produce complete paralysis of the limb although sensory abilities are normally preserved. Functional electrical stimulation (FES), robotics and brain computer interfaces (BCIs) have been used to induce motor rehabilitation. In this work we measured the brain activity of healthy volunteers using electroencephalography (EEG) during FES, passive movements, active movements, motor imagery of the hand and resting to compare afferent and efferent brain signals produced during these motor related activities and to define possible features for an online FES-BCI. In the conditions in which the hand was moved we limited the movement range in order to control the afferent flow. Although we observed that there is a subject dependent frequency and spatial distribution of efferent and afferent signals, common patterns between conditions and subjects were present mainly in the low beta frequency range. When averaging all the subjects together the most significant frequency bin comparing each condition versus rest was exactly the same for all conditions but motor imagery. These results suggest that to implement an on-line FES-BCI, afferent brain signals resulting from FES have to be filtered and time-frequency-spatial features need to be used.

  1. 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.

  2. Unmyelinated visceral afferents exhibit frequency dependent action potential broadening while myelinated visceral afferents do not.

    PubMed

    Li, Bai-Yan; Feng, Bin; Tsu, Hwa Y; Schild, John H

    2007-06-21

    Sensory information arising from visceral organ systems is encoded into action potential trains that propagate along afferent fibers to target nuclei in the central nervous system. These information streams range from tight patterns of action potentials that are well synchronized with the sensory transduction event to irregular, patternless discharge with no clear correlation to the sensory input. In general terms these afferent pathways can be divided into unmyelinated and myelinated fiber types. Our laboratory has a long standing interest in the functional differences between these two types of afferents in terms of the preprocessing of sensory information into action potential trains (synchrony, frequency, duration, etc.), the reflexogenic consequences of this sensory input to the central nervous system and the ionic channels that give rise to the electrophysiological properties of these unique cell types. The aim of this study was to determine whether there were any functional differences in the somatic action potential characteristics of unmyelinated and myelinated vagal afferents in response to different rates of sensory nerve stimulation. Our results showed that activity and frequency-dependent widening of the somatic action potential was quite prominent in unmyelinated but not myelinated vagal afferents. Spike broadening often leads to increased influx of Ca(2+) ions that has been associated with a diverse range of modulatory mechanisms both at the cell body and central synaptic terminations (e.g. increased neurotransmitter release.) We conclude that our observations are indicative of fundamentally different mechanisms for neural integration of sensory information arising from unmyelinated and myelinated vagal afferents.

  3. Microcurrent electrical nerve stimulation facilitates regrowth of mouse soleus muscle.

    PubMed

    Ohno, Yoshitaka; Fujiya, Hiroto; Goto, Ayumi; Nakamura, Ayane; Nishiura, Yuka; Sugiura, Takao; Ohira, Yoshinobu; Yoshioka, Toshitada; Goto, Katsumasa

    2013-01-01

    Microcurrent electrical nerve stimulation (MENS) has been used to facilitate recovery from skeletal muscle injury. However, the effects of MENS on unloading-associated atrophied skeletal muscle remain unclear. Effects of MENS on the regrowing process of unloading-associated atrophied skeletal muscle were investigated. Male C57BL/6J mice (10-week old) were randomly assigned to untreated normal recovery (C) and MENS-treated (M) groups. Mice of both groups are subjected to continuous hindlimb suspension (HS) for 2 weeks followed by 7 days of ambulation recovery. Mice in M group were treated with MENS for 60 min 1, 3, and 5 days following HS, respectively, under anesthesia. The intensity, the frequency, and the pulse width of MENS were set at 10 μA, 0.3 Hz, and 250 msec, respectively. Soleus muscles were dissected before and immediately after, 1, 3 and 7 days after HS. Soleus muscle wet weight and protein content were decreased by HS. The regrowth of atrophied soleus muscle in M group was faster than that in C group. Decrease in the reloading-induced necrosis of atrophied soleus was facilitated by MENS. Significant increases in phosphorylated levels of p70 S6 kinase and protein kinase B (Akt) in M group were observed, compared with C group. These observations are consistent with that MENS facilitated regrowth of atrophied soleus muscle. MENS may be a potential extracellular stimulus to activate the intracellular signals involved in protein synthesis.

  4. Revealing humans’ sensorimotor functions with electrical cortical stimulation

    PubMed Central

    Desmurget, Michel; Sirigu, Angela

    2015-01-01

    Direct electrical stimulation (DES) of the human brain has been used by neurosurgeons for almost a century. Although this procedure serves only clinical purposes, it generates data that have a great scientific interest. Had DES not been employed, our comprehension of the organization of the sensorimotor systems involved in movement execution, language production, the emergence of action intentionality or the subjective feeling of movement awareness would have been greatly undermined. This does not mean, of course, that DES is a gold standard devoid of limitations and that other approaches are not of primary importance, including electrophysiology, modelling, neuroimaging or psychophysics in patients and healthy subjects. Rather, this indicates that the contribution of DES cannot be restricted, in humans, to the ubiquitous concepts of homunculus and somatotopy. DES is a fundamental tool in our attempt to understand the human brain because it represents a unique method for mapping sensorimotor pathways and interfering with the functioning of localized neural populations during the performance of well-defined behavioural tasks. PMID:26240422

  5. Use of transcutaneous electrical nerve stimulation for chronic pruritus.

    PubMed

    Mohammad Ali, Basma Mourad; Hegab, Doaa Salah; El Saadany, Hanan Mohammad

    2015-01-01

    Pruritus is a distressing symptom in many dermatological as well as systemic conditions, and it is sometimes very chronic and relapsing. Transcutaneous electrical nerve stimulation (TENS) is an inexpensive form of analgesia that could also ameliorate itching. This study aimed to evaluate TENS efficacy in patients with pruritus due to some types of chronic eczema, and in patients with chronic hepatic disease. Ten patients with atopic dermatitis (AD), 20 patients with lichen simplex chronicus (LSC), and 16 patients with chronic liver disease having chronic distressing pruritus received three sessions of TENS weekly for 12 sessions, and the effect on the visual analogue scale (VAS) scores was recorded after 2 weeks of therapy, at treatment end, and after an additional month for follow up. There was a statistically significant decline in the mean VAS score for studied groups at weeks 2 and 4 of therapy compared to baseline, but the improvement was more significant in patients with AD, and LSC (p < 0.001 for both) than in those with chronic liver disease (p < 0.01) who also showed an early re-elevation of VAS score on follow up. TENS therapy holds promise as a palliative, alternative, safe and inexpensive treatment for patients with some chronic pruritic conditions.

  6. Primate translational vestibuloocular reflexes. III. Effects of bilateral labyrinthine electrical stimulation

    NASA Technical Reports Server (NTRS)

    Angelaki, D. E.; McHenry, M. Q.; Dickman, J. D.; Perachio, A. A.

    2000-01-01

    The effects of functional, reversible ablation and potential recruitment of the most irregular otolith afferents on the dynamics and sensitivity of the translational vestibuloocular reflexes (trVORs) were investigated in rhesus monkeys trained to fixate near and far targets. Translational motion stimuli consisted of either steady-state lateral and fore-aft sinusoidal oscillations or short-lasting transient lateral head displacements. Short-duration (usually <2 s) anodal (inhibitory) and cathodal (excitatory) currents (50-100 microA) were delivered bilaterally during motion. In the presence of anodal labyrinthine stimulation, trVOR sensitivity and its dependence on viewing distance were significantly decreased. In addition, anodal currents significantly increased phase lags. During transient motion, anodal stimulation resulted in significantly lower initial eye acceleration and more sluggish responses. Cathodal currents tended to have opposite effects. The main characteristics of these results were simulated by a simple model where both regularly and irregularly discharging afferents contribute to the trVORs. Anodal labyrinthine currents also were found to decrease eye velocity during long-duration, constant velocity rotations, although results were generally more variable compared with those during translational motion.

  7. Field potentials generated by group II muscle afferents in the lower-lumbar segments of the feline spinal cord

    PubMed Central

    Riddell, J S; Hadian, M

    2000-01-01

    The actions of group II muscle afferents projecting to the lower-lumbar (L6 and L7) segments of the cat spinal cord were investigated by recording the cord dorsum and focal synaptic field potentials evoked by electrical stimulation of hindlimb muscle nerves. Cord dorsum potentials recorded over the lower-lumbar segments were generally much smaller than those produced by group II afferents terminating within the midlumbar and sacral segments. Only group II afferents of tibialis posterior produced potentials with an amplitude (mean maximal amplitude 39 μV, n = 7) approaching that of potentials over other segments. Focal synaptic potentials (mean maximal amplitudes 135–200 μV) were evoked by group II afferents of the following muscle nerves, listed in order of effectiveness: quadriceps, tibialis posterior (throughout L6 and L7), gastrocnemius soleus, flexor digitorum longus, posterior biceps-semitendinosus and popliteus (mainly within L7). Field potentials were recorded in the dorsal horn (laminae IV–V) and also more ventrally in a region which included the lateral part of the intermediate zone (lateral to the large group I intermediate field potentials) and often extended into the ventral horn (laminae V–VII). The latencies of the group II potentials are considered compatible with the monosynaptic actions of the fastest conducting group II muscle afferents. The results are compared with morphological evidence on the pattern of termination of group II muscle afferents in the lower-lumbar segments and with previous descriptions of the actions of group II muscle afferents in midlumbar and sacral segments. PMID:10618155

  8. Microprocessor controlled movement of liquid gastric content using sequential neural electrical stimulation

    PubMed Central

    Mintchev, M; Sanmiguel, C; Otto, S; Bowes, K

    1998-01-01

    Background—Gastric electrical stimulation has been attempted for several years with little success. 
Aims—To determine whether movement of liquid gastric content could be achieved using microprocessor controlled sequential electrical stimulation. 
Methods—Eight anaesthetised dogs underwent laparotomy and implantation of four sets of bipolar stainless steel wire electrodes. Each set consisted of two to six electrodes (10×0.25 mm, 3 cm apart) implanted circumferentially. The stomach was filled with water and the process of gastric emptying was monitored. Artificial contractions were produced using microprocessor controlled phase locked bipolar four second trains of 50 Hz, 14 V (peak to peak) rectangular voltage. In four of the dogs four force transducers were implanted close to each circumferential electrode set. In one gastroparetic patient the effect of direct electrical stimulation was determined at laparotomy. 
Results—Using the above stimulating parameters circumferential gastric contractions were produced which were artificially propagated distally by phase locking the stimulating voltage. Averaged stimulated gastric emptying times were significantly shorter than spontaneus emptying times (t1/2 6.7 (3.0) versus 25.3 (12.9) minutes, p<0.01). Gastric electrical stimulation of the gastroparetic patient at operation produced circumferential contractions. 
Conclusions—Microprocessor controlled electrical stimulation produced artificial peristalsis and notably accelerated the movement of liquid gastric content. 

 Keywords: gastric electrical stimulation; gastric motility PMID:9824339

  9. Fundamentals of Transcranial Electric and Magnetic Stimulation Dose: Definition, Selection, and Reporting Practices

    PubMed Central

    Peterchev, Angel V.; Wagner, Timothy A.; Miranda, Pedro C.; Nitsche, Michael A.; Paulus, Walter; Lisanby, Sarah H.; Pascual-Leone, Alvaro; Bikson, Marom

    2011-01-01

    The growing use of transcranial electric and magnetic (EM) brain stimulation in basic research and in clinical applications necessitates a clear understanding of what constitutes the dose of EM stimulation and how it should be reported. The biological effects of EM stimulation are mediated through an electromagnetic field injected (via electric stimulation) or induced (via magnetic stimulation) in the body. Therefore, transcranial EM stimulation dose ought to be defined by all parameters of the stimulation device that affect the electromagnetic field generated in the body, including the stimulation electrode or coil configuration parameters: shape, size, position, and electrical properties, as well as the electrode or coil current (or voltage) waveform parameters: pulse shape, amplitude, width, polarity, and repetition frequency; duration of and interval between bursts or trains of pulses; total number of pulses; and interval between stimulation sessions and total number of sessions. Knowledge of the electromagnetic field generated in the body may not be sufficient but is necessary to understand the biological effects of EM stimulation. We believe that reporting of EM stimulation dose should be guided by the principle of reproducibility: sufficient information about the stimulation parameters should be provided so that the dose can be replicated. This paper provides fundamental definition and principles for reporting of dose that encompass any transcranial EM brain stimulation protocol. PMID:22305345

  10. A Novel In Vitro System for Comparative Analyses of Bone Cells and Bacteria under Electrical Stimulation

    PubMed Central

    Zaatreh, Sarah; Kreikemeyer, Bernd

    2016-01-01

    Electrical stimulation is a promising approach to enhance bone regeneration while having potential to inhibit bacterial growth. To investigate effects of alternating electric field stimulation on both human osteoblasts and bacteria, a novel in vitro system was designed. Electric field distribution was simulated numerically and proved by experimental validation. Cells were stimulated on Ti6Al4V electrodes and in short distance to electrodes. Bacterial growth was enumerated in supernatant and on the electrode surface and biofilm formation was quantified. Electrical stimulation modulated gene expression of osteoblastic differentiation markers in a voltage-dependent manner, resulting in significantly enhanced osteocalcin mRNA synthesis rate on electrodes after stimulation with 1.4VRMS. While collagen type I synthesis increased when stimulated with 0.2VRMS, it decreased after stimulation with 1.4VRMS. Only slight and infrequent influence on bacterial growth was observed following stimulations with 0.2VRMS and 1.4VRMS after 48 and 72 h, respectively. In summary this novel test system is applicable for extended in vitro studies concerning definition of appropriate stimulation parameters for bone cell growth and differentiation, bacterial growth suppression, and investigation of general effects of electrical stimulation. PMID:28044132

  11. Simulation of the electrically stimulated cochlear neuron: modeling adaptation to trains of electric pulses.

    PubMed

    Woo, Jihwan; Miller, Charles A; Abbas, Paul J

    2009-05-01

    The Hodgkin-Huxley (HH) model does not simulate the significant changes in auditory nerve fiber (ANF) responses to sustained stimulation that are associated with neural adaptation. Given that the electric stimuli used by cochlear prostheses can result in adapted responses, a computational model incorporating an adaptation process is warranted if such models are to remain relevant and contribute to related research efforts. In this paper, we describe the development of a modified HH single-node model that includes potassium ion ( K(+)) concentration changes in response to each action potential. This activity-related change results in an altered resting potential, and hence, excitability. Our implementation of K(+)-related changes uses a phenomenological approach based upon K(+) accumulation and dissipation time constants. Modeled spike times were computed using repeated presentations of modeled pulse-train stimuli. Spike-rate adaptation was characterized by rate decrements and time constants and compared against ANF data from animal experiments. Responses to relatively low (250 pulse/s) and high rate (5000 pulse/s) trains were evaluated and the novel adaptation model results were compared against model results obtained without the adaptation mechanism. In addition to spike-rate changes, jitter and spike intervals were evaluated and found to change with the addition of modeled adaptation. These results provide one means of incorporating a heretofore neglected (although important) aspect of ANF responses to electric stimuli. Future studies could include evaluation of alternative versions of the adaptation model elements and broadening the model to simulate a complete axon, and eventually, a spatially realistic model of the electrically stimulated nerve within extracochlear tissues.

  12. A method for the study of the effects of combining multiple pseudorandom fusimotor stimulation on the responses of muscle-spindle primary-ending afferents.

    PubMed

    Hulliger, Manuel; Banks, Robert W

    2009-03-30

    We describe a new method of investigation of the integrative action of fusimotor inputs in mammalian muscle spindles by stimulation of multiple fusimotor axons using independent pseudorandom pulse trains, each of low mean rate with pseudorandomly distributed stimulus intervals. Technically it was feasible only because of the development of (1) a novel, highly efficient approach to functional isolation of fusimotor efferents in ventral-root filaments, which we have called the isodyne strategy; (2) a real-time, microprocessor-based stimulus artefact cancellation device (SACAD); and (3) a highly adjustable, multi-branch stimulation electrode array. The general approach of using multiple, independent, pseudorandom stimulation of several input channels has wider applications in controlled-activation paradigms.

  13. Probing the physiology of ASH neuron in Caenorhabditis elegans using electric current stimulation

    PubMed Central

    Chokshi, Trushal Vijaykumar; Bazopoulou, Daphne; Chronis, Nikos

    2011-01-01

    Electrical stimulation has been widely used to modulate and study the in vitro and in vivo functionality of the nervous system. Here, we characterized the effect of electrical stimulation on ASH neuron in Caenorhabditis elegans and employed it to probe the neuron’s age dependent properties. We utilized an automated microfluidic-based platform and characterized the ASH neuronal activity in response to an electric current applied to the worm’s body. The electrically induced ASH neuronal response was observed to be dependent on the magnitude, polarity, and spatial location of the electrical stimulus as well as on the age of the worm. PMID:21886270

  14. Spike sorting of muscle spindle afferent nerve activity recorded with thin-film intrafascicular electrodes.

    PubMed

    Djilas, Milan; Azevedo-Coste, Christine; Guiraud, David; Yoshida, Ken

    2010-01-01

    Afferent muscle spindle activity in response to passive muscle stretch was recorded in vivo using thin-film longitudinal intrafascicular electrodes. A neural spike detection and classification scheme was developed for the purpose of separating activity of primary and secondary muscle spindle afferents. The algorithm is based on the multiscale continuous wavelet transform using complex wavelets. The detection scheme outperforms the commonly used threshold detection, especially with recordings having low signal-to-noise ratio. Results of classification of units indicate that the developed classifier is able to isolate activity having linear relationship with muscle length, which is a step towards online model-based estimation of muscle length that can be used in a closed-loop functional electrical stimulation system with natural sensory feedback.

  15. Transcutaneous Electrical Nerve Stimulation Improves Exercise Tolerance in Healthy Subjects.

    PubMed

    Tomasi, F P; Chiappa, G; Maldaner da Silva, V; Lucena da Silva, M; Lima, A S C G B; Arena, R; Bottaro, M; Cipriano, G

    2015-07-01

    Transcutaneous electrical nerve stimulation (TENS) increases peripheral blood flow by attenuation of the muscle metaboreflex, improving oxygen supply to working muscles. We tested the hypothesis that application of TENS at ganglion improves exercise performance. 11 subjects underwent constant-work rate tests (CWR) to the limit of tolerance (Tlim) while receiving TENS or placebo. Oxygen uptake (V.O2), carbon dioxide (V.CO2), minute ventilation (V.E), ventilatory equivalent (V.E/V.CO2), heart rate (HR) and oxygen pulse (V.O2/HR) were analyzed at isotime separated by percentile and Tlim. V.O2 was lower and V.CO2 was higher at 100% of isotime during TENS, while there were no differences in V.E and V.E/V.CO2. HR was lower during exercise with TENS, and V.O2/HR increased at peak exercise (17.96±1.9 vs. 20.38±1 ml/min/bpm, P<0.05). TENS increased mechanical efficiency at isotime and Tlim (4.10±0.50 vs. 3.39±0.52%, P<0.05 and 3.95±0.67 vs. 3.77±0.45%, P<0.05) and exercise tolerance compared to P-TENS (390±41 vs. 321±41 s; P<0.05). Our data shows that the application of TENS can potentially increase exercise tolerance and oxygen supply in healthy subjects.

  16. [Electrical failure with nerve stimulation: cases report and check list for prevention].

    PubMed

    Choquet, O; Feugeas, J-L; Capdevila, X; Manelli, J-C

    2007-03-01

    Functionality of the nerve stimulator and integrity of the electrical circuit should be verified and confirmed before performing peripheral nerve blockade. The clinical cases reported here demonstrate that electrical disconnection or malfunction during nerve localization can unpredictably occur and a checklist is described to prevent the unknown electrical circuit failure.

  17. Pain and soreness associated with a percutaneous electrical stimulation muscle cramping protocol.

    PubMed

    Miller, Kevin C; Knight, Kenneth L

    2007-11-01

    Muscle cramps are difficult to study scientifically because of their spontaneity and unpredictability. Various laboratory techniques to induce muscle cramps have been explored but the best technique for inducing cramps is unclear. Electrical stimulation appears to be the most reliable, but there is a perception that it is extremely painful. Data to support this perception are lacking. We hypothesized that electrical stimulation is a tolerable method of inducing cramps with few side effects. We measured cramp frequency (HZ), pain during electrical stimulation, and soreness before, at 5 s, and 30, 60, and 90 min after cramp induction using a 100-mm visual analog scale. Group 1 received tibial nerve stimulation on 5 consecutive days; Group 2 received it on alternate days for five total treatments. Pain and soreness were mild. The highest ratings occurred on Day 1 and decreased thereafter. Intersession reliability was high. Our study showed that electrical stimulation causes little pain or soreness and is a reliable method for inducing cramps.

  18. Dopamine D1/D5, But not D2/D3, Receptor Dependency of Synaptic Plasticity at Hippocampal Mossy Fiber Synapses that Is Enabled by Patterned Afferent Stimulation, or Spatial Learning.

    PubMed

    Hagena, Hardy; Manahan-Vaughan, Denise

    2016-01-01

    Although the mossy fiber (MF) synapses of the hippocampal CA3 region display quite distinct properties in terms of the molecular mechanisms that underlie synaptic plasticity, they nonetheless exhibit persistent (>24 h) synaptic plasticity that is akin to that observed at the Schaffer collateral (SCH)-CA1 and perforant path (PP)-dentate gyrus (DG) synapses of freely behaving rats. In addition, they also respond to novel spatial learning with very enduring forms of long-term potentiation (LTP) and long-term depression (LTD). These latter forms of synaptic plasticity are directly related to the learning behavior: novel exploration of generalized changes in space facilitates the expression of LTP at MF-CA3 synapses, whereas exploration of novel configurations of large environmental features facilitates the expression of LTD. In the absence of spatial novelty, synaptic plasticity is not expressed. Motivation is a potent determinant of whether learning about the spatial experience effectively occurs and the neuromodulator dopamine (DA) plays a key role in motivation-based learning. Prior research on the regulation by DA receptors of long-term synaptic plasticity in CA1 and DG synapses in vivo suggests that whereas D2/D3 receptors may modulate a general predisposition toward expressing plasticity, D1/D5 receptors may directly regulate the direction of change in synaptic strength that occurs during learning. Although the CA3 region is believed to play a pivotal role in many forms of learning, the role of dopamine receptors in persistent (>24 h) forms of synaptic plasticity at MF-CA3 synapses is unknown. Here, we report that whereas pharmacological antagonism of D2/D3 receptors had no impact on LTP or LTD, antagonism of D1/D5 receptors significantly impaired LTP and LTD that were induced by solely by means of patterned afferent stimulation, or LTP/LTD that are typically enhanced by the conjunction of afferent stimulation and novel spatial learning. These data indicate an

  19. Dopamine D1/D5, But not D2/D3, Receptor Dependency of Synaptic Plasticity at Hippocampal Mossy Fiber Synapses that Is Enabled by Patterned Afferent Stimulation, or Spatial Learning

    PubMed Central

    Hagena, Hardy; Manahan-Vaughan, Denise

    2016-01-01

    Although the mossy fiber (MF) synapses of the hippocampal CA3 region display quite distinct properties in terms of the molecular mechanisms that underlie synaptic plasticity, they nonetheless exhibit persistent (>24 h) synaptic plasticity that is akin to that observed at the Schaffer collateral (SCH)-CA1 and perforant path (PP)-dentate gyrus (DG) synapses of freely behaving rats. In addition, they also respond to novel spatial learning with very enduring forms of long-term potentiation (LTP) and long-term depression (LTD). These latter forms of synaptic plasticity are directly related to the learning behavior: novel exploration of generalized changes in space facilitates the expression of LTP at MF-CA3 synapses, whereas exploration of novel configurations of large environmental features facilitates the expression of LTD. In the absence of spatial novelty, synaptic plasticity is not expressed. Motivation is a potent determinant of whether learning about the spatial experience effectively occurs and the neuromodulator dopamine (DA) plays a key role in motivation-based learning. Prior research on the regulation by DA receptors of long-term synaptic plasticity in CA1 and DG synapses in vivo suggests that whereas D2/D3 receptors may modulate a general predisposition toward expressing plasticity, D1/D5 receptors may directly regulate the direction of change in synaptic strength that occurs during learning. Although the CA3 region is believed to play a pivotal role in many forms of learning, the role of dopamine receptors in persistent (>24 h) forms of synaptic plasticity at MF-CA3 synapses is unknown. Here, we report that whereas pharmacological antagonism of D2/D3 receptors had no impact on LTP or LTD, antagonism of D1/D5 receptors significantly impaired LTP and LTD that were induced by solely by means of patterned afferent stimulation, or LTP/LTD that are typically enhanced by the conjunction of afferent stimulation and novel spatial learning. These data indicate an

  20. Different Movement of Hyolaryngeal Structures by Various Application of Electrical Stimulation in Normal Individuals

    PubMed Central

    Kim, Sae Hyun; Oh, Byung-Mo; Han, Tae Ryun; Jeong, Ho Joong

    2015-01-01

    Objective To identify the differences in the movement of the hyoid bone and the vocal cord with and without electrical stimulation in normal subjects. Methods Two-dimensional motion analysis using a videofluoroscopic swallowing study with and without electrical stimulation was performed. Surface electrical stimulation was applied during swallowing using electrodes placed at three different locations on each subject. All subjects were analyzed three times using the following electrode placements: with one pair of electrodes on the suprahyoid muscles and a second pair on the infrahyoid muscles (SI); with placement of the electrode pairs on only the infrahyoid muscles (IO); and with the electrode pairs placed vertically on the suprahyoid and infrahyoid muscles (SIV). Results The main outcomes of this study demonstrated an initial downward displacement as well as different movements of the hyoid bone with the three electrode placements used for electrical stimulation. The initial positions of the hyoid bone with the SI and IO placements resulted in an inferior and anterior displaced position. During swallowing, the hyoid bone moved in a more superior and less anterior direction, resulting in almost the same peak position compared with no electrical stimulation. Conclusion These results demonstrate that electrical stimulation caused an initial depression of the hyoid bone, which had nearly the same peak position during swallowing. Electrical stimulation during swallowing was not dependent on the position of the electrode on the neck, such as on the infrahyoid or on both the suprahyoid and infrahyoid muscles. PMID:26361589

  1. Enhanced chondrocyte densities on carbon nanotube composites: the combined role of nanosurface roughness and electrical stimulation.

    PubMed

    Khang, Dongwoo; Park, Grace E; Webster, Thomas J

    2008-07-01

    Simultaneous incorporation of intrinsic nanosurface roughness and external electrical stimulation may maximize the regeneration of articular cartilage tissue more than on nanosmooth, electrically nonstimulated biomaterials. Here, we report enhanced functions of chondrocytes (cartilage synthesizing cells) on electrically and nonelectrically stimulated highly dispersed carbon nanotubes (CNT) in polycarbonate urethane (PCU) compared to, respectively, stimulated pure PCU. Specifically, compared to conventional longitudinal (or vertical) electrical stimulation of chondrocytes on conducting surfaces which require high voltage, we developed a lateral electrical stimulation across CNT/PCU composite films of low voltage that enhanced chondrocyte functions. Chondrocyte adhesion and long-term cell densities (up to 2 days) were enhanced (more than 50%) on CNT/PCU composites compared to PCU alone without electrical stimulation. This study further explained why by measuring greater amounts of initial fibronectin adsorption (a key protein that mediates chondrocyte adhesion) on CNT/PCU composites which were more hydrophilic (than pure PCU) due to greater nanometer roughness. Importantly, the same trend was observed and was even significantly enhanced when chondrocytes were subjected to electrical stimulation (more than 200%) compared to nonstimulated CNT/PCU. For this reason, this study provided direct evidence of the positive role that conductive CNT/PCU films can play in promoting functions of chondrocytes for cartilage regeneration.

  2. The sympathetic skin response: normal values, elucidation of afferent components and application limits.

    PubMed

    Uncini, A; Pullman, S L; Lovelace, R E; Gambi, D

    1988-11-01

    The sympathetic skin response (SSR), recorded at the hand and foot, was elicited using different classes of stimuli in 20 normal controls and 10 patients with peripheral neuropathy. We found that SSR latencies changed significantly with different recording sites, but not with different stimulation sites. Additionally, after ischemic conduction block of the arm in 3 normal controls, the previously obtainable SSR recorded at the hand became unobtainable with median nerve stimulation. Also, in one patient with subacute ganglionitis and 3 patients with demyelinating neuropathies, the SSR could not be elicited by electrical stimulation, but it could with deep inspiration. These results suggest that large diameter myelinated fibers may serve as afferents for the SSR. Furthermore, these findings imply that an unobtainable SSR by electrical stimulation may be due not only to dysfunction of the autonomic efferent nerve fibers, but also to abnormalities of the sensory afferents of the reflex. Therefore, investigations of autonomic dysfunction utilizing the SSR must be interpreted with caution in patients with peripheral neuropathies.

  3. Delay-Dependent Response in Weakly Electric Fish under Closed-Loop Pulse Stimulation.

    PubMed

    Forlim, Caroline Garcia; Pinto, Reynaldo Daniel; Varona, Pablo; Rodríguez, Francisco B

    2015-01-01

    In this paper, we apply a real time activity-dependent protocol to study how freely swimming weakly electric fish produce and process the timing of their own electric signals. Specifically, we address this study in the elephant fish, Gnathonemus petersii, an animal that uses weak discharges to locate obstacles or food while navigating, as well as for electro-communication with conspecifics. To investigate how the inter pulse intervals vary in response to external stimuli, we compare the response to a simple closed-loop stimulation protocol and the signals generated without electrical stimulation. The activity-dependent stimulation protocol explores different stimulus delivery delays relative to the fish's own electric discharges. We show that there is a critical time delay in this closed-loop interaction, as the largest changes in inter pulse intervals occur when the stimulation delay is below 100 ms. We also discuss the implications of these findings in the context of information processing in weakly electric fish.

  4. Electrical stimulation enhances cell migration and integrative repair in the meniscus

    NASA Astrophysics Data System (ADS)

    Yuan, Xiaoning; Arkonac, Derya E.; Chao, Pen-Hsiu Grace; Vunjak-Novakovic, Gordana

    2014-01-01

    Electrical signals have been applied towards the repair of articular tissues in the laboratory and clinical settings for over seventy years. We focus on healing of the meniscus, a tissue essential to knee function with limited innate repair potential, which has been largely unexplored in the context of electrical stimulation. Here we demonstrate for the first time that electrical stimulation enhances meniscus cell migration and integrative tissue repair. We optimize pulsatile direct current electrical stimulation parameters on cells at the micro-scale, and apply these to healing of full-thickness defects in explants at the macro-scale. We report increased expression of the adenosine A2b receptor in meniscus cells after stimulation at the micro- and macro-scale, and propose a role for A2bR in meniscus electrotransduction. Taken together, these findings advance our understanding of the effects of electrical signals and their mechanisms of action, and contribute to developing electrotherapeutic strategies for meniscus repair.

  5. The electrical stimulation of tibial osteotomies. Double-blind study.

    PubMed

    Mammi, G I; Rocchi, R; Cadossi, R; Massari, L; Traina, G C

    1993-03-01

    The effect of electromagnetic field stimulation was investigated in a group of 40 consecutive patients treated with valgus tibial osteotomy for degenerative arthrosis of the knee. All patients were operated on by the same author and followed the same postoperative program. After surgery, patients were randomly assigned to a control group (dummy stimulators) or to a stimulated one (active stimulators). Four orthopedic surgeons, unaware of the experimental conditions, were asked to evaluate the roentgenograms taken 60 days postoperatively and to rate the osteotomy healing according to four categories (the fourth category being the most advanced stage of healing). In the control group, 73.6% of the patients were included in the first and second category. In the stimulated group, 72.2% of the patients were included in the third and fourth category. On a homogeneous group of patients, electromagnetic field stimulation had positive effects on the healing of tibial osteotomies.

  6. Primary afferent response to signals in the intestinal lumen.

    PubMed

    Raybould, H

    2001-02-01

    The first recordings of vagal afferent nerve fibre activity were performed by Paintal in the early 1950s. In these experiments, he showed that phenyldiguanide (later recognized as a 5-HT3 receptor agonist) stimulated the firing of C-fibres innervating the intestine. In the following years, ample physiological and psychological studies have demonstrated the importance of afferent information arising from the gut in the regulation of gastrointestinal function and behaviour. Many stimuli are capable of eliciting these functional effects and of stimulating afferent fibre discharge, including mechanical, chemical, nutrient- and immune-derived stimuli. Studies in the last 10 years have begun to focus on the precise sensory transduction mechanisms by which these visceral primary afferent nerve terminals are activated and, like the contribution by Zhu et al. in this issue of The Journal of Physiology, are revealing some novel and exciting findings.

  7. Electrical stimulation promotes sensory neuron regeneration and growth-associated gene expression.

    PubMed

    Geremia, Nicole M; Gordon, Tessa; Brushart, Thomas M; Al-Majed, Abdulhakeem A; Verge, Valerie M K

    2007-06-01

    Brief electrical stimulation enhances the regenerative ability of axotomized motor [Nix, W.A., Hopf, H.C., 1983. Electrical stimulation of regenerating nerve and its effect on motor recovery. Brain Res. 272, 21-25; Al-Majed, A.A., Neumann, C.M., Brushart, T.M., Gordon, T., 2000. Brief electrical stimulation promotes the speed and accuracy of motor axonal regeneration. J. Neurosci. 20, 2602-2608] and sensory [Brushart, T.M., Jari, R., Verge, V., Rohde, C., Gordon, T., 2005. Electrical stimulation restores the specificity of sensory axon regeneration. Exp. Neurol. 194, 221-229] neurons. Here we examined the parameter of duration of stimulation on regenerative capacity, including the intrinsic growth programs, of sensory neurons. The effect of 20 Hz continuous electrical stimulation on the number of DRG sensory neurons that regenerate their axons was evaluated following transection and surgical repair of the femoral nerve trunk. Stimulation was applied proximal to the repair site for 1 h, 3 h, 1 day, 7 days or 14 days at the time of nerve repair. Following a 21-day regeneration period, DRG neurons that regenerated axons into the muscle and cutaneous sensory nerve branches were retrogradely identified. Stimulation of 1 h led to a significant increase in DRG neurons regenerating into cutaneous and muscle branches when compared to 0 h (sham) stimulation or longer periods of stimulation. Stimulation for 1 h also significantly increased the numbers of neurons that regenerated axons beyond the repair site 4 days after lesion and was correlated with a significant increase in expression of growth-associated protein 43 (GAP-43) mRNA in the regenerating neurons at 2 days post-repair. An additional indicator of heightened plasticity following 1 h stimulation was elevated expression of brain-derived neurotrophic factor (BDNF). The effect of brief stimulation on enhancing sensory and motoneuron regeneration holds promise for inducing improved peripheral nerve repair in the

  8. Observation of pressure stimulated voltages in rocks using an electric potential sensor

    SciTech Connect

    Aydin, A.; Prance, R. J.; Prance, H.; Harland, C. J.

    2009-09-21

    Recent interest in the electrical activity in rock and the use of electric field transients as candidates for earthquake precursors has led to studies of pressure stimulated currents in laboratory samples. In this paper, an electric field sensor is used to measure directly the voltages associated with these currents. Stress was applied as uniaxial compression to marble and granite at an approximately constant rate. In contrast with the small pressure stimulated currents previously measured, large voltage signals are reported. Polarity reversal of the signal was observed immediately before fracture for the marble, in agreement with previous pressure stimulated current studies.

  9. [Localization of peripheral nerves. Success and safety with electrical nerve stimulation].

    PubMed

    Neuburger, M; Schwemmer, U; Volk, T; Gogarten, W; Kessler, P; Steinfeldt, T

    2014-05-01

    Peripheral electrical nerve stimulation is one of the standard applications in peripheral regional anesthesia in addition to the ultrasound technique. Among other findings, the visualization of needle and nerve during ultrasound-guided blockade caused a change in clinical practice of peripheral nerve stimulation in the last decade. In the present article old and new aspects of principles and clinical practice of the nerve stimulation technique are presented and summarized in a total clinical concept in order to achieve safe and successful peripheral regional anesthesia using electrical peripheral nerve stimulation.

  10. Primary Sensory and Motor Cortex Excitability Are Co-Modulated in Response to Peripheral Electrical Nerve Stimulation

    PubMed Central

    Schabrun, Siobhan M.; Ridding, Michael C.; Galea, Mary P.; Hodges, Paul W.; Chipchase, Lucinda S.

    2012-01-01

    Peripheral electrical stimulation (PES) is a common clinical technique known to induce changes in corticomotor excitability; PES applied to induce a tetanic motor contraction increases, and PES at sub-motor threshold (sensory) intensities decreases, corticomotor excitability. Understanding of the mechanisms underlying these opposite changes in corticomotor excitability remains elusive. Modulation of primary sensory cortex (S1) excitability could underlie altered corticomotor excitability with PES. Here we examined whether changes in primary sensory (S1) and motor (M1) cortex excitability follow the same time-course when PES is applied using identical stimulus parameters. Corticomotor excitability was measured using transcranial magnetic stimulation (TMS) and sensory cortex excitability using somatosensory evoked potentials (SEPs) before and after 30 min of PES to right abductor pollicis brevis (APB). Two PES paradigms were tested in separate sessions; PES sufficient to induce a tetanic motor contraction (30–50 Hz; strong motor intensity) and PES at sub motor-threshold intensity (100 Hz). PES applied to induce strong activation of APB increased the size of the N20-P25 component, thought to reflect sensory processing at cortical level, and increased corticomotor excitability. PES at sensory intensity decreased the size of the P25-N33 component and reduced corticomotor excitability. A positive correlation was observed between the changes in amplitude of the cortical SEP components and corticomotor excitability following sensory and motor PES. Sensory PES also increased the sub-cortical P14-N20 SEP component. These findings provide evidence that PES results in co-modulation of S1 and M1 excitability, possibly due to cortico-cortical projections between S1 and M1. This mechanism may underpin changes in corticomotor excitability in response to afferent input generated by PES. PMID:23227260

  11. Primary sensory and motor cortex excitability are co-modulated in response to peripheral electrical nerve stimulation.

    PubMed

    Schabrun, Siobhan M; Ridding, Michael C; Galea, Mary P; Hodges, Paul W; Chipchase, Lucinda S

    2012-01-01

    Peripheral electrical stimulation (PES) is a common clinical technique known to induce changes in corticomotor excitability; PES applied to induce a tetanic motor contraction increases, and PES at sub-motor threshold (sensory) intensities decreases, corticomotor excitability. Understanding of the mechanisms underlying these opposite changes in corticomotor excitability remains elusive. Modulation of primary sensory cortex (S1) excitability could underlie altered corticomotor excitability with PES. Here we examined whether changes in primary sensory (S1) and motor (M1) cortex excitability follow the same time-course when PES is applied using identical stimulus parameters. Corticomotor excitability was measured using transcranial magnetic stimulation (TMS) and sensory cortex excitability using somatosensory evoked potentials (SEPs) before and after 30 min of PES to right abductor pollicis brevis (APB). Two PES paradigms were tested in separate sessions; PES sufficient to induce a tetanic motor contraction (30-50 Hz; strong motor intensity) and PES at sub motor-threshold intensity (100 Hz). PES applied to induce strong activation of APB increased the size of the N(20)-P(25) component, thought to reflect sensory processing at cortical level, and increased corticomotor excitability. PES at sensory intensity decreased the size of the P25-N33 component and reduced corticomotor excitability. A positive correlation was observed between the changes in amplitude of the cortical SEP components and corticomotor excitability following sensory and motor PES. Sensory PES also increased the sub-cortical P(14)-N(20) SEP component. These findings provide evidence that PES results in co-modulation of S1 and M1 excitability, possibly due to cortico-cortical projections between S1 and M1. This mechanism may underpin changes in corticomotor excitability in response to afferent input generated by PES.

  12. Bioreactor for modulation of cardiac microtissue phenotype by combined static stretch and electrical stimulation

    PubMed Central

    Miklas, Jason W; Nunes, Sara S; Sofla, Aarash; Reis, Lewis A; Pahnke, Aric; Xiao, Yun; Laschinger, Carol; Radisic, Milica

    2014-01-01

    We describe here a bioreactor capable of simultaneously applying mechanical and electrical field stimulation in conjunction with static strain and on-line force of contraction measurements. It consisted of a polydimethylsiloxane (PDMS) tissue chamber and a pneumatically driven stretch platform. The chamber contained eight tissue microwells (8.05 mm in length and 2.5 mm in width) with a pair of posts (2.78 mm in height and 0.8 mm in diameter) in each well to serve as fixation points and for measurements of contraction force. Carbon rods, stimulating electrodes, were placed into the PDMS chamber such that one pair stimulated four microwells. For feasibility studies, neonatal rat cardiomyocytes were seeded in collagen gels into the microwells. Following three days of gel compaction, electrical field stimulation at 3–4 V/cm and 1Hz, mechanical stimulation of 5% static strain or electromechanical stimulation (field stimulation at 3–4 V/cm, 1Hz and 5% static strain) were applied for 3 days. Cardiac microtissues subjected to electromechanical stimulation exhibited elevated amplitude of contraction and improved sarcomere structure as evidenced by sarcomeric α-actinin, actin and troponin T staining compared to microtissues subjected to electrical or mechanical stimulation alone or non-stimulated controls. The expression of atrial natriuretic factor and brain natriuretic peptide was also elevated in the electromechanically stimulated group. PMID:24876342

  13. Long-range projections of Adelta primary afferents in the Lissauer tract of the rat.

    PubMed

    Lidierth, Malcolm

    2007-09-25

    Electrical microstimulation has been used to activate fine myelinated primary afferents running within the Lissauer tract. Stimulation of the tract at the L2/L3 border produced antidromic volleys which were recorded on the dorsal roots of more caudal spinal segments. Antidromic volleys were present in all cases for roots as far caudal as the S2 segment (L3, n=12; L4, n=6; L5, n=6; L6, n=9; S1, n=3; S2, n=6; observations in a total of 15 rats). These fibres were collaterals of primary afferents with conduction velocities in the dorsal root of up to 17.3+/-2.3 ms(-1) (mean+/-S.D., n=6; range 14-20 ms(-1)). Conduction velocities within the Lissauer tract were slower; the fastest contributing fibres had conduction velocities of 9.2+/-2.2 ms(-1) (range 6-12 ms(-1)). Lesions of the Lissauer tract caudal to the stimulation site abolished the volleys on roots lying caudal to the lesion. Most previous works have suggested that primary afferents project in the Lissauer tract for only one or two spinal segments. The present study shows that some fibres project rostrally for up to seven spinal segments (L2-S2).

  14. Patterns of connectivity of spinal interneurons with single muscle afferents.

    PubMed

    Quevedo, J; Eguibar, J R; Lomeli, J; Rudomin, P

    1997-07-01

    A technique was developed to measure, in the anesthetized and paralyzed cat under artificial ventilation, changes of excitability to intraspinal stimulation simultaneously in two different afferent fibers or in two collaterals of the same afferent fiber. Intraspinal stimulation reduced the threshold of single muscle afferent fibers ending in the intermediate nucleus. This effect was seen with strengths below those required to activate the afferent fiber tested (1.5-12 microA), occurred at a short latency (1.5-2.0 ms), reached a maximum between 15 and 30 ms, and lasted up to 100 ms. The effects produced by graded stimulation applied at the shortest conditioning-testing stimulus time intervals increased by fixed steps, suggesting recruitment of discrete elements, most likely of last-order interneurons mediating primary afferent depolarization (PAD). The short-latency increases in excitability produced by the weakest effective intraspinal stimuli were usually detected only in the collateral closest to the stimulating micropipette, indicating that the stimulated interneurons mediating PAD have spatially restricted actions. The short-latency PAD produced by intraspinal stimuli, as well as the PAD produced by stimulation of the posterior biceps and semitendinosus (PBSt) nerve or by stimulation of the bulbar reticular formation (RF), was depressed 19-30 min after the i.v. injection of 0.5 mg/kg of picrotoxin, suggesting that all these effects were mediated by GABAergic mechanisms. The PAD elicited by stimulation of muscle and/or cutaneous nerves was depressed following the i.v. injection of (-)-baclofen, whereas the PAD elicited in the same collateral by stimulation of the RF was baclofen-resistant. The short-latency PAD produced by intraspinal stimulation was not always depressed by i.v. injections of (-)-baclofen. Baclofen-sensitive and baclofen-resistant monosynaptic PADs could be produced in different collaterals of the same afferent fiber. The results suggest that

  15. Tissue heterogeneity as a mechanism for localized neural stimulation by applied electric fields

    NASA Astrophysics Data System (ADS)

    Miranda, P. C.; Correia, L.; Salvador, R.; Basser, P. J.

    2007-09-01

    We investigate the heterogeneity of electrical conductivity as a new mechanism to stimulate excitable tissues via applied electric fields. In particular, we show that stimulation of axons crossing internal boundaries can occur at boundaries where the electric conductivity of the volume conductor changes abruptly. The effectiveness of this and other stimulation mechanisms was compared by means of models and computer simulations in the context of transcranial magnetic stimulation. While, for a given stimulation intensity, the largest membrane depolarization occurred where an axon terminates or bends sharply in a high electric field region, a slightly smaller membrane depolarization, still sufficient to generate action potentials, also occurred at an internal boundary where the conductivity jumped from 0.143 S m-1 to 0.333 S m-1, simulating a white-matter-grey-matter interface. Tissue heterogeneity can also give rise to local electric field gradients that are considerably stronger and more focal than those impressed by the stimulation coil and that can affect the membrane potential, albeit to a lesser extent than the two mechanisms mentioned above. Tissue heterogeneity may play an important role in electric and magnetic 'far-field' stimulation.

  16. Afferent and efferent connections of the diencephalic prepacemaker nucleus in the weakly electric fish, Eigenmannia virescens: interactions between the electromotor system and the neuroendocrine axis.

    PubMed

    Wong, C J

    1997-06-23

    The afferent and efferent connections of the gymnotiform central posterior nucleus of the dorsal thalamus and prepacemaker nucleus (CP/PPn) were examined by retrograde and anterograde transport of the small molecular weight tracer, Neurobiotin. The CP/PPn was identified by physiological assay and received a local iontophoretic injection of Neurobiotin. Retrogradely labeled somata were observed in the ventral telencephalon, hypothalamus, and the pretectal nucleus electrosensorius. Anterogradely labeled fibers were traced from the CP/PPn to the ventral telencephalon, the hypothalamus, the neuropil immediately adjacent to the most rostral subdivision of the nucleus electrosensorius, the optic tectum, and the pacemaker nucleus. Retrograde transport of tracer following injections into the ventral telencephalon, preoptic area, lateral hypothalamus, tectum, and pacemaker nucleus confirmed these efferent targets. A rostromedial subarea of the CP/PPn can be identified that projects to basal forebrain regions and to a lateral region of the CP/PPn that contains afferents to the pacemaker. Many of the targets, which are connected with the CP/PPn, have been linked to reproductive behavior or neuroendocrine control in other fishes. A comparative analysis reveals that the efferent pathways of the CP/PPn appear similar and may be homologous to efferent pathways of some components of the auditory thalamus among tetrapods.

  17. Effect of Electrical Stimulation on Blood Flow Velocity and Vessel Size

    PubMed Central

    Jin, Hee-Kyung; Hwang, Tae-Yeon; Cho, Sung-Hyoun

    2017-01-01

    Abstract Interferential current electrical stimulation alters blood flow velocity and vessel size. We aimed to investigate the changes in the autonomic nervous system depending on electrical stimulation parameters. Forty-five healthy adult male and female subjects were studied. Bipolar adhesive pad electrodes were used to stimulate the autonomic nervous system at the thoracic vertebrae 1-4 levels for 20 min. Using Doppler ultrasonography, blood flow was measured to determine velocity and vessel size before, immediately after, and 30 min after electrical stimulation. Changes in blood flow velocity were significantly different immediately and 30 min after stimulation. The interaction between intervention periods and groups was significantly different between the exercise and pain stimulation groups immediately after stimulation (p<0.05). The vessel size was significantly different before and 30 min after stimulation (p<0.05). Imbalances in the sympathetic nervous system, which regulates balance throughout the body, may present with various symptoms. Therefore, in the clinical practice, the parameters of electrical stimulation should be selectively applied in accordance with various conditions and changes in form.

  18. Cochlear dead regions constrain the benefit of combining acoustic stimulation with electric stimulation

    PubMed Central

    Zhang, Ting; Dorman, Michael F.; Gifford, Rene; Moore, Brian C.J.

    2014-01-01

    Objective The aims of this study were to (i) detect the presence and edge frequency (fe) of a cochlear dead region in the ear with residual acoustic hearing for bimodal cochlear implant (CI) users, and (ii) determine whether amplification based on the presence or absence of a dead region would improve speech understanding and sound quality. Design Twenty two listeners with a CI in one ear and residual acoustic hearing in the non-implanted ear were tested. Eleven listeners had a cochlear dead region in the acoustic-hearing ear and eleven did not. Dead regions were assessed with the threshold equalizing noise (TEN) and the sweeping noise, psychophysical tuning curve (SWPTC) tests. Speech understanding was assessed with monosyllabic words and the AzBio sentences at +10 dB signal-to-noise ratio. Speech and music quality judgments were obtained with the Judgment of Sound Quality questionnaire. Results For this population, using shifted tips of the PTCs as a basis for diagnosis, the TEN had high sensitivity (0.91) and poor specificity (0.55). The value of fe was lower when estimated with the SWPTC test than with the TEN test. For the listeners with cochlear dead regions, speech understanding, speech quality and music quality were best when no amplification was applied for frequencies within the dead region. For listeners without dead regions, speech understanding was best with full-bandwidth amplification and was reduced when amplification was not applied when the audiometric threshold exceeded 80 dB HL. Conclusion Our data suggest that, to improve bimodal benefit for listeners who combine electric and acoustic stimulation, audiologists should routinely test for the presence of cochlear dead regions and determine amplification bandwidth accordingly. PMID:24950254

  19. Stimulating Music: The Pleasures and Dangers of “Electric Music,” 1750–1900

    PubMed Central

    Kennaway, James

    2014-01-01

    Far from being a purely modern idea, the notion of “electric music” was already common in the eighteenth and nineteenth centuries. The shift in thinking about music from cosmic harmony to nervous stimulation made metaphors and speculative theories relating music and electricity irresistible. This essay considers the development of the idea of electric music, looking at its associations with a sexual “body electric.” It will then examine how this conception of music went from being the subject of sympathy to becoming part of a medical critique of music as a dangerous stimulant, with echoes in music criticism and beyond. PMID:24587689

  20. Stimulating Music: The Pleasures and Dangers of "Electric Music," 1750-1900.

    PubMed

    Kennaway, James

    2011-01-01

    Far from being a purely modern idea, the notion of "electric music" was already common in the eighteenth and nineteenth centuries. The shift in thinking about music from cosmic harmony to nervous stimulation made metaphors and speculative theories relating music and electricity irresistible. This essay considers the development of the idea of electric music, looking at its associations with a sexual "body electric." It will then examine how this conception of music went from being the subject of sympathy to becoming part of a medical critique of music as a dangerous stimulant, with echoes in music criticism and beyond.

  1. Electrical stimulation of the rostral medial prefrontal cortex in rabbits inhibits the expression of conditioned eyelid responses but not their acquisition

    PubMed Central

    Leal-Campanario, Rocío; Fairén, Alfonso; Delgado-García, José M.; Gruart, Agnès

    2007-01-01

    We have studied the role of rostral medial prefrontal cortex (mPFC) on reflexively evoked blinks and on classically conditioned eyelid responses in alert-behaving rabbits. The rostral mPFC was identified by its afferent projections from the medial half of the thalamic mediodorsal nuclear complex. Classical conditioning consisted of a delay paradigm using a 370-ms tone as the conditioned stimulus (CS) and a 100-ms air puff directed at the left cornea as the unconditioned stimulus (US). The CS coterminated with the US. Electrical train stimulation of the contralateral rostral mPFC produced a significant inhibition of air-puff-evoked blinks. The same train stimulation of the rostral mPFC presented during the CS–US interval for 10 successive conditioning sessions significantly reduced the generation of conditioned responses (CRs) as compared with values reached by control animals. Interestingly, the percentage of CRs almost reached control values when train stimulation of the rostral mPFC was removed from the fifth conditioning session on. The electrical stimulation of the rostral mPFC in well conditioned animals produced a significant decrease in the percentage of CRs. Moreover, the stimulation of the rostral mPFC was also able to modify the kinematics (latency, amplitude, and velocity) of evoked CRs. These results suggest that the rostral mPFC is a potent inhibitor of reflexively evoked and classically conditioned eyeblinks but that activation prevents only the expression of CRs, not their latent acquisition. Functional and behavioral implications of this inhibitory role of the rostral mPFC are discussed. PMID:17592148

  2. Selectivity and resolution of surface electrical stimulation for grasp and release.

    PubMed

    Westerveld, Ard J; Schouten, Alfred C; Veltink, Peter H; van der Kooij, Herman

    2012-01-01

    Electrical stimulation of arm and hand muscles can be a functional tool for patients with motor dysfunction. Sufficient stimulation of finger and thumb musculature can support natural grasping function. Yet it remains unclear how different grasping movements can be selectively supported by electrical stimulation. The goal of this study is to determine to what extent activation of individual fingers is possible with surface electrical stimulation for the purpose of rehabilitation following stroke. The extensor digitorum communis (EDC) muscle, flexor pollicis longus (FPL) muscle, and the thenar muscle group, all involved in grasp and release, were selected for stimulation. The evoked forces in individual fingers were measured. Stimulation thresholds and selective ranges were determined for each subject. Electrode locations where the highest selective range occurred were compared between subjects and influences of different isometric wrist positions were assessed. In all subjects selective stimulation of middle finger extension and thumb flexion was possible. In addition, selective stimulation of index and ring finger extension was possible in most cases. In nine out of the ten EDC subjects we were able to stimulate three or all four fingers selectively. However, large variability in electrode locations for high selectivity was observed between the subjects. Within the designs of grasping prostheses and grasping rehabilitation devices, the variability of electrode locations should be taken into account. The results of our study facilitate the optimization of such designs and favour a design which allows individualized stimulation locations.

  3. [Description of conditioned reflex elaboration in cats in response to electric stimulation of the hippocampal formation].

    PubMed

    Fomin, B A

    1981-01-01

    In six cats with chronically implanted brain electrodes conditioned running to the feeding trough was elaborated in response to electrical stimulation of the ventral hippocampal formation (VHF), which at first produced inhibition of running. The stages of conditioning were as follows: 1) inhibition of conditioned activity; 2) replacement of inhibition by more frequent runnings--generalization of the conditioned reflex; 3) enhancement of signal significance of VHF electrical stimulation and subsequent decrease of intersignal reactions. Conditioned reflex to electrical stimulation of CA1 field was elaborated slower than that to electrical stimulation of other VHF points. At the beginning of conditioning a periodic decrease of probability of conditioned reactions manifestation was observed, which is estimated as an additional characteristic of the hippocampus activity.

  4. Muscle fiber type specific induction of slow myosin heavy chain 2 gene expression by electrical stimulation

    SciTech Connect

    Crew, Jennifer R.; Falzari, Kanakeshwari; DiMario, Joseph X.

    2010-04-01

    Vertebrate skeletal muscle fiber types are defined by a broad array of differentially expressed contractile and metabolic protein genes. The mechanisms that establish and maintain these different fiber types vary throughout development and with changing functional demand. Chicken skeletal muscle fibers can be generally categorized as fast and fast/slow based on expression of the slow myosin heavy chain 2 (MyHC2) gene in fast/slow muscle fibers. To investigate the cellular and molecular mechanisms that control fiber type formation in secondary or fetal muscle fibers, myoblasts from the fast pectoralis major (PM) and fast/slow medial adductor (MA) muscles were isolated, allowed to differentiate in vitro, and electrically stimulated. MA muscle fibers were induced to express the slow MyHC2 gene by electrical stimulation, whereas PM muscle fibers did not express the slow MyHC2 gene under identical stimulation conditions. However, PM muscle fibers did express the slow MyHC2 gene when electrical stimulation was combined with inhibition of inositol triphosphate receptor (IP3R) activity. Electrical stimulation was sufficient to increase nuclear localization of expressed nuclear-factor-of-activated-T-cells (NFAT), NFAT-mediated transcription, and slow MyHC2 promoter activity in MA muscle fibers. In contrast, both electrical stimulation and inhibitors of IP3R activity were required for these effects in PM muscle fibers. Electrical stimulation also increased levels of peroxisome-proliferator-activated receptor-{gamma} co-activator-1 (PGC-1{alpha}) protein in PM and MA muscle fibers. These results indicate that MA muscle fibers can be induced by electrical stimulation to express the slow MyHC2 gene and that fast PM muscle fibers are refractory to stimulation-induced slow MyHC2 gene expression due to fast PM muscle fiber specific cellular mechanisms involving IP3R activity.

  5. Restoration of Bladder and Bowel Function Using Electrical Stimulation and Block after Spinal Cord Injury

    DTIC Science & Technology

    2015-10-01

    clinical trial have been ordered from the manufacturer. 15. SUBJECT TERMS Spinal Cord Injuries, Neurogenic Bladder, Electric Stimulation 16... Clinical  Trial 3. Participant recruitment, surgery, participant evaluation for Stage 1 4. Surgery, participant evaluation for Stage 2 5. Data analysis and...publication This is a prospective Phase 1 clinical trial of an implanted electrical stimulator to improve both continence and voiding in human

  6. Electric Field Stimulation Enhances Healing of Post-Traumatic Osteoarthritic Cartilage

    DTIC Science & Technology

    2015-10-01

    AWARD NUMBER: W81XWH-14-1-0591 TITLE: Electric Field Stimulation Enhances Healing of Post-Traumatic Osteoarthritic Cartilage PRINCIPAL...DATES COVERED 30 Sep 2014 – 29 Sep 2015 4. TITLE AND SUBTITLE Electric Field Stimulation Enhances Healing of Post-Traumatic Osteoarthritic Cartilage...instability, among other traumatic affections of joints, and occupations or sports that subject joints to high levels of impact and torsional loading

  7. The relief of microtherm inhibition for p-fluoronitrobenzene mineralization using electrical stimulation at low temperatures.

    PubMed

    Zhang, Xueqin; Feng, Huajun; Liang, Yuxiang; Zhao, Zhiqing; Long, Yuyang; Fang, Yuan; Wang, Meizhen; Yin, Jun; Shen, Dongsheng

    2015-05-01

    Low temperature aggravates biological treatment of refractory p-fluoronitrobenzene (p-FNB) because of microtherm inhibition of microbial activity. Considering the potential characterization of energy supply for microbial metabolism and spurring microbial activity by electrical stimulation, a bioelectrochemical system (BES) was established to provide sustaining electrical stimulation for p-FNB mineralization at a low temperature. Electrical stimulation facilitated p-FNB treatment and bioelectrochemical reaction rate constants for the removal and defluorination of p-FNB at 10 °C were 0.0931 and 0.0054 h(-1), which were higher than the sums of the rates found using a biological system and an electrocatalytic system by 62.8 and 64.8%, respectively. At a low temperature, microbial activity in terms of dehydrogenase and ATPase was found to be higher with electrical stimulation, being 121.1 and 100.1% more active than that in the biological system. Moreover, stronger antioxidant ability was observed in the BES, which implied a better cold-resistance and relief of microtherm inhibition by electrical stimulation. Bacterial diversity analysis revealed a significant evolution of microbial community by electrical stimulation, and Clostridia was uniquely enriched. One bacterial sequence close to Pseudomonas became uniquely predominant, which appeared to be crucial for excellent p-FNB treatment performance in the BES at a low temperature. Economic evaluation revealed that the energy required to mineralize an extra mole of p-FNB was found to be 247 times higher by heating the system than by application of electrical stimulation. These results indicated that application of electrical stimulation is extremely promising for treating refractory waste at low temperatures.

  8. Raphe magnus and reticulospinal actions on primary afferent depolarization of group I muscle afferents in the cat.

    PubMed

    Quevedo, J; Eguibar, J R; Jiménez, I; Rudomin, P

    1995-02-01

    1. In the anaesthetized cat, electrical stimulation of the bulbar reticular formation produced a short latency (2.1 +/- 0.3 ms) positive potential in the cord dorsum. In contrast, stimulation of the nucleus raphe magnus with strengths below 50 microA evoked a slow negative potential with a mean latency of 5.5 +/- 0.6 ms that persisted after sectioning the contralateral pyramid and was abolished by sectioning the ipsilateral dorsolateral funiculus. 2. The field potentials evoked by stimulation of the bulbar reticular formation and of the nucleus raphe magnus had a different intraspinal distribution, suggesting activation of different sets of segmental interneurones. 3. Stimulation of these two supraspinal nuclei produced primary afferent depolarization (PAD) in single Ib fibres and inhibited the PAD elicited by group I volleys in single Ia fibres. The inhibition of the PAD of Ia fibres produced by reticulospinal and raphespinal inputs appears to be exerted on different interneurones along the PAD pathway. 4. It is concluded that, although reticulospinal and raphespinal pathways have similar inhibitory effects on PAD of Ia fibres, and similar excitatory effects on the PAD of Ib fibres, their actions are conveyed by partly independent pathways. This would allow their separate involvement in the control of posture and movement.

  9. Raphe magnus and reticulospinal actions on primary afferent depolarization of group I muscle afferents in the cat.

    PubMed Central

    Quevedo, J; Eguibar, J R; Jiménez, I; Rudomin, P

    1995-01-01

    1. In the anaesthetized cat, electrical stimulation of the bulbar reticular formation produced a short latency (2.1 +/- 0.3 ms) positive potential in the cord dorsum. In contrast, stimulation of the nucleus raphe magnus with strengths below 50 microA evoked a slow negative potential with a mean latency of 5.5 +/- 0.6 ms that persisted after sectioning the contralateral pyramid and was abolished by sectioning the ipsilateral dorsolateral funiculus. 2. The field potentials evoked by stimulation of the bulbar reticular formation and of the nucleus raphe magnus had a different intraspinal distribution, suggesting activation of different sets of segmental interneurones. 3. Stimulation of these two supraspinal nuclei produced primary afferent depolarization (PAD) in single Ib fibres and inhibited the PAD elicited by group I volleys in single Ia fibres. The inhibition of the PAD of Ia fibres produced by reticulospinal and raphespinal inputs appears to be exerted on different interneurones along the PAD pathway. 4. It is concluded that, although reticulospinal and raphespinal pathways have similar inhibitory effects on PAD of Ia fibres, and similar excitatory effects on the PAD of Ib fibres, their actions are conveyed by partly independent pathways. This would allow their separate involvement in the control of posture and movement. Images Figure 6 PMID:7738852

  10. Mechanical power of ankle plantar flexion and subjective pain by monophasic electrical stimulation.

    PubMed

    Suzuki, Tatsuto; Watanabe, Takashi; Saura, Ryuichi; Uchiyama, Hironobu

    2011-01-01

    The aim of this study was to investigate the mechanical power of the ankle plantar flexion. The investigated power of the ankle plantar flexion would help to improve effectively the FES walking system using the ankle plantar flexion for patients and aged people in slow walking. The subjective pain by electrical stimulation sometimes becomes the burden to use the FES system. We also investigated the relationship between the mechanical power in ankle plantar flexion by electrical stimulation and the subjective pain. We developed the device to measure the ankle movement by electrical stimulation against load resistance torque. The device consisted of pads to support a single lower leg, a rotational footplate with a large pulley and a vertical weight to generate the load resistance torque, and a monophasic electrical stimulator via surface electrodes. Our results showed the proportional relationship between the mechanical power of the ankle plantar flexion and the subjective pain by electrical stimulation. To generate the same level in the ankle plantar flexor power 2.75 W under the maximum voluntary exertion, the subjective pain by electrical stimulation exceeded 70, which means the feeling of crying at the Face Pain Scale. This result would help the better design of the FES walking system using the ankle plantar flexion for patients and aged people.

  11. 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.

  12. 9 CFR 307.7 - Safety requirements for electrical stimulating (EST) equipment.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... beam sensors form the enclosure, the stimulating equipment shall be automatically shut off when the sensor signals are broken. (3) Mandatory Warning Devices and Signals. The following warning devices or.... (ii) An ANSI Z53.1-Color Code sign reading (a) “Danger Electrical Hazard” for stimulating...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 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...

  14. Electrical stimulation partly reverses the muscle insulin resistance caused by tenotomy.

    PubMed

    Langfort, J; Czarnowski, D; Budohoski, L; Górski, J; Kaciuba-Uściłko, H; Nazar, K

    1993-01-04

    It was shown that 15-min electrical stimulation of the rat sciatic nerve greatly increases the in vitro measured sensitivity of lactate formation, glucose transport, and glycogen synthesis to insulin, impaired by previous tenotomy. The insulin sensitivity of all these processes was, however, still below that found in the stimulated intact soleus muscle. Extending the stimulation up to 30 min did not cause any further changes in insulin sensitivity either in tenotomized or in intact muscles.

  15. Direct cortical stimulation but not transcranial electrical stimulation motor evoked potentials detect brain ischemia during brain tumor resection.

    PubMed

    Li, Fenghua; Deshaies, Eric M; Allott, Geoffrey; Canute, Gregory; Gorji, Reza

    2011-09-01

    Motor evoked potentials (MEPs) elicited by both direct cortical stimulation (DCS) and transcranial electrical stimulation are used during brain tumor resection. Parallel use of direct cortical stimulation motor evoked potentials (DCS-MEPs) and transcranial electrical stimulation motor evoked potentials (TCeMEPs) has been practiced during brain tumor resection. We report that DCS-MEPs elicited by direct subdural grid stimulation, but not TCeMEPs, detected brain ischemia during brain tumor resection. Following resection of a brainstem high-grade glioma in a 21-year-old, the threshold of cortical motor-evoked-potentials (cMEPs) increased from 13 mA to 20 mA while amplitudes decreased. No changes were noted in transcranial motor evoked potentials (TCMEPs), somatosensory evoked potentials (SSEPs), auditory evoked potentials (AEPs), anesthetics, or hemodynamic parameters. Our case showed the loss of cMEPs and SSEPs, but not TCeMEPs. Permanent loss of DCS-MEPs and SSEPs was correlated with permanent left hemiplegia in our patient even when appropriate action was taken. Parallel use of DCS- and TCeMEPs with SSEPs improves sensitivity of intraoperative detection of motor impairment. DCS may be superior to TCeMEPs during brain tumor resection.

  16. On the Cause and Control of Residual Voltage Generated by Electrical Stimulation of Neural Tissue

    PubMed Central

    Krishnan, Ashwati; Kelly, Shawn K.

    2016-01-01

    Functional electrical stimulation of neural tissue is traditionally performed with symmetric cathodic-first biphasic pulses of current through an electrode/electrolyte interface. When the interface is modeled by a series R-C circuit, as is sometimes done for stimulator circuit design, the appearance of a net residual voltage across the electrode cannot be explained. Residual voltage can cause polarization of the electrode and pose a problem for safe electrical stimulation. This paper aims to (1) theoretically explain one reason for the residual voltage, which is the inclusion of the Faradaic impedance (2) suggest a simple dynamic feedback mechanism to eliminate residual voltage. PMID:23366780

  17. Intrusive Thoughts Elicited by Direct Electrical Stimulation during Stereo-Electroencephalography

    PubMed Central

    Popa, Irina; Donos, Cristian; Barborica, Andrei; Opris, Ioan; Mălîia, Mihai Dragoş; Ene, Mirela; Ciurea, Jean; Mîndruţă, Ioana

    2016-01-01

    Cortical direct electrical stimulation (DES) is a method of brain mapping used during invasive presurgical evaluation of patients with intractable epilepsy. Intellectual auras like intrusive thoughts, also known as forced thinking (FT), have been reported during frontal seizures. However, there are few reports on FT obtained during DES in frontal cortex. We report three cases in which we obtained intrusive thoughts while stimulating the dorsolateral prefrontal cortex and the white matter in the prefrontal region. In order to highlight the effective connectivity that might explain this clinical response, we have analyzed cortico-cortical potentials evoked by single pulse electrical stimulation. PMID:27486431

  18. Effect of Epidural Electrical Stimulation and Repetitive Transcranial Magnetic Stimulation in Rats With Diffuse Traumatic Brain Injury

    PubMed Central

    Yoon, Yong-Soon; Cho, Kang Hee; Kim, Eun-Sil; Lee, Mi-Sook

    2015-01-01

    Objective To evaluate the effects of epidural electrical stimulation (EES) and repetitive transcranial magnetic stimulation (rTMS) on motor recovery and brain activity in a rat model of diffuse traumatic brain injury (TBI) compared to the control group. Methods Thirty rats weighing 270-285 g with diffuse TBI with 45 kg/cm2 using a weight-drop model were assigned to one of three groups: the EES group (ES) (anodal electrical stimulation at 50 Hz), the rTMS group (MS) (magnetic stimulation at 10 Hz, 3-second stimulation with 6-second intervals, 4,000 total stimulations per day), and the sham-treated control group (sham) (no stimulation). They were pre-trained to perform a single-pellet reaching task (SPRT) and a rotarod test (RRT) for 14 days. Diffuse TBI was then induced and an electrode was implanted over the dominant motor cortex. The changes in SPRT success rate, RRT performance time rate and the expression of c-Fos after two weeks of EES or rTMS were tracked. Results SPRT improved significantly from day 8 to day 12 in the ES group and from day 4 to day 14 in the MS group (p<0.05) compared to the sham group. RRT improved significantly from day 6 to day 11 in ES and from day 4 to day 9 in MS compared to the sham group. The ES and MS groups showed increased expression of c-Fos in the cerebral cortex compared to the sham group. Conclusion ES or MS in a rat model of diffuse TBI can be used to enhance motor recovery and brain activity. PMID:26161348

  19. Modeling and simulation of the bending behavior of electrically-stimulated cantilevered hydrogels

    NASA Astrophysics Data System (ADS)

    Attaran, Abdolhamid; Brummund, Jörg; Wallmersperger, Thomas

    2015-03-01

    A systematic development of a chemo-electro-mechanical continuum model—for the application of electrically-stimulated cantilevered hydrogels—and its numerical implementation are presented in this work. The governing equations are derived within the framework of the continuum mechanics of mixtures. The finite element method is then utilized for the numerical treatment of the model. For the numerical simulation a cantilevered strip of an anionic hydrogel immersed in a NaCl solution bath is considered. An electric field is applied to electrically stimulate the aforementioned hydrogel. The application of the electric field alters the initial concentrations of the ionic species due to the chemo-electrical coupling. The gradual increase in the applied electric field leads to the bending movement of the hydrogel. Concluding, the presented multi-field continuum model is capable of simulating hydrogel bending actuators and also more complex systems e.g. gel finger grippers.

  20. Reliable EEG responses to the selective activation of C-fibre afferents using a temperature-controlled infrared laser stimulator in conjunction with an adaptive staircase algorithm.

    PubMed

    Jankovski, Aleksandar; Plaghki, Léon; Mouraux, André

    2013-09-01

    Brain responses to the activation of C-fibres are obtained only if the co-activation of Aδ-fibres is avoided. Methods to activate C-fibres selectively have been proposed, but are unreliable or difficult to implement. Here, we propose an approach combining a new laser stimulator to generate constant-temperature heat pulses with an adaptive paradigm to maintain stimulus temperature above the threshold of C-fibres but below that of Aδ-fibres, and examine whether this approach can be used to record reliable C-fibre laser-evoked brain potentials. Brief CO2 laser stimuli were delivered to the hand and foot dorsum of 10 healthy subjects. The stimuli were generated using a closed-loop control of laser power by an online monitoring of target skin temperature. The adaptive algorithm, using reaction times to distinguish between late detections indicating selective activation of unmyelinated C-fibres and early detections indicating co-activation of myelinated Aδ-fibres, allowed increasing the likelihood of selectively activating C-fibres. Reliable individual-level electroencephalogram (EEG) responses were identified, both in the time domain (hand: N2: 704 ± 179 ms, P2: 984 ± 149 ms; foot: N2: 1314 ± 171 ms, P2: 1716 ± 171 ms) and the time-frequency (TF) domain. Using a control dataset in which no stimuli were delivered, a Receiver Operating Characteristics analysis showed that the magnitude of the phase-locked EEG response corresponding to the N2-P2, objectively quantified in the TF domain, discriminated between absence vs presence of C-fibre responses with a high sensitivity (hand: 85%, foot: 80%) and specificity (hand: 90%, foot: 75%). This approach could thus be particularly useful for the diagnostic workup of small-fibre neuropathies and neuropathic pain.

  1. Sulfonated polyaniline-based organic electrodes for controlled electrical stimulation of human osteosarcoma cells.

    PubMed

    Min, Yong; Yang, Yanyin; Poojari, Yadagiri; Liu, Yidong; Wu, Jen-Chieh; Hansford, Derek J; Epstein, Arthur J

    2013-06-10

    Electrically conducting polymers (CPs) were found to stimulate various cell types such as neurons, osteoblasts, and fibroblasts in both in vitro and in vivo studies. However, to our knowledge, no studies have been reported on the utility of CPs in stimulation of cancer or tumor cells in the literature. Here we report a facile fabrication method of self-doped sulfonated polyaniline (SPAN)-based interdigitated electrodes (IDEs) for controlled electrical stimulation of human osteosarcoma (HOS) cells. Increased degree of sulfonation was found to increase the SPAN conductivity, which in turn improved the cell attachment and cell growth without electrical stimulation. However, an enhanced cell growth was observed under controlled electrical (AC) stimulation at low applied voltage and frequency (≤800 mV and ≤1 kHz). The cell growth reached a maximum threshold at an applied voltage or frequency and beyond which pronounced cell death was observed. We believe that these organic electrodes may find utility in electrical stimulation of cancer or tumor cells for therapy and research and may also provide an alternative to the conventional metal-based electrodes.

  2. Chronic effects of low-frequency low-intensity electrical stimulation of stretched human muscle

    NASA Astrophysics Data System (ADS)

    Shenkman, Boris S.; Lyubaeva, Ekaterina V.; Popov, Daniil V.; Netreba, Aleksey I.; Bravy, Yan R.; Tarakin, Pavel P.; Lemesheva, Yulia S.; Vinogradova, Olga L.

    2007-02-01

    Effects of low-frequency electrical stimulation, which is currently considered to be a possible countermeasure for long-duration spaceflights, with and without stretch were evaluated. Twelve young male volunteers were randomly distributed into two groups. In one group anterior thigh muscles—knee extensors of both legs were stimulated with frequency of 15 Hz for 4.5 wks, six times a week; each session was 6-h long. In the other group, electrical stimulation with the same parameters was applied to stretched knee extensors. Following stimulation the subjects exhibited an increase in fatigue resistance, and in the succinate dehydrogenase activity and a 10% gain in the percentage of muscle fibers with slow myosin heavy chain isoforms. In a stimulated group the peak voluntary strength went down significantly, the CSA of fast muscle fibers in m. quadriceps femoris became slightly less in size (10%). Electrical stimulation of the stretched muscles induced an insignificant decline in their strength and an increase of cross-sectional area of muscle fibers of both types. Thus chronic low-frequency electrical stimulation may be proposed as a candidate countermeasure against muscle strength and mass loss if it is combined with stretch.

  3. [Interest of EEG recording during direct electrical stimulation for brain mapping function in surgery].

    PubMed

    Trebuchon, A; Guye, M; Tcherniack, V; Tramoni, E; Bruder, N; Metellus, P

    2012-06-01

    Brain tumor surgery is at risk when lesions are located in eloquent areas. The interindividual anatomo-functional variability of the central nervous system implies that brain surgery within eloquent regions may induce neurological sequelae. Brain mapping using intraoperative direct electrical stimulation in awake patients has been for long validated as the standard for functional brain mapping. Direct electrical stimulation inducing a local transient electrical and functional disorganization is considered positive if the task performed by the patient is disturbed. The brain area stimulated is then considered as essential for the function tested. However, the exactitude of the information provided by this technique is cautious because the actual impact of cortical direct electrical stimulation is not known. Indeed, the possibility of false negative (insufficient intensity of the stimulation due to the heterogeneity of excitability threshold of different cortical areas) or false positive (current spread, interregional signal propagation responsible for remote effects, which make difficult the interpretation of positive or negative behavioural effects) constitute a limitation of this technique. To improve the sensitivity and specificity of this technique, we used an electrocorticographic recording system allowing a real time visualization of the local. We provide here evidence that direct cortical stimulation combined with electrocorticographic recording could be useful to detect remote after discharge and to adjust stimulation parameters. In addition this technique offers new perspective to better assess connectivity of cerebral networks.

  4. Biphasic Electrical Field Stimulation Aids in Tissue Engineering of Multicell-Type Cardiac Organoids

    PubMed Central

    Chiu, Loraine L.Y.; Iyer, Rohin K.; King, John-Paul

    2011-01-01

    The main objectives of current work were (1) to compare the effects of monophasic or biphasic electrical field stimulation on structure and function of engineered cardiac organoids based on enriched cardiomyocytes (CM) and (2) to determine if electrical field stimulation will enhance electrical excitability of cardiac organoids based on multiple cell types. Organoids resembling cardiac myofibers were cultivated in Matrigel-coated microchannels fabricated of poly(ethylene glycol)-diacrylate. We found that field stimulation using symmetric biphasic square pulses at 2.5 V/cm, 1 Hz, 1 ms (per pulse phase) was an improved stimulation protocol, as compared to no stimulation and stimulation using monophasic square pulses of identical total amplitude and duration (5 V/cm, 1 Hz, 2 ms). This was supported by the highest success rate for synchronous contractions, low excitation threshold, the highest cell density, and the highest expression of Connexin-43 in the biphasic group. Subsequently, enriched CM were seeded on the networks of (1) cardiac fibroblasts (FB), (2) D4T endothelial cells (EC), or (3) a mixture of FB and EC that were precultured for 2 days prior to the addition of enriched CM. Biphasic field stimulation was also effective at improving electrical excitability of these cardiac organoids by improving the three-dimensional organization of the cells, increasing cellular elongation and enhancing Connexin-43 presence. PMID:18783322

  5. Biphasic electrical field stimulation aids in tissue engineering of multicell-type cardiac organoids.

    PubMed

    Chiu, Loraine L Y; Iyer, Rohin K; King, John-Paul; Radisic, Milica

    2011-06-01

    The main objectives of current work were (1) to compare the effects of monophasic or biphasic electrical field stimulation on structure and function of engineered cardiac organoids based on enriched cardiomyocytes (CM) and (2) to determine if electrical field stimulation will enhance electrical excitability of cardiac organoids based on multiple cell types. Organoids resembling cardiac myofibers were cultivated in Matrigel-coated microchannels fabricated of poly(ethylene glycol)-diacrylate. We found that field stimulation using symmetric biphasic square pulses at 2.5 V/cm, 1 Hz, 1 ms (per pulse phase) was an improved stimulation protocol, as compared to no stimulation and stimulation using monophasic square pulses of identical total amplitude and duration (5 V/cm, 1 Hz, 2 ms). This was supported by the highest success rate for synchronous contractions, low excitation threshold, the highest cell density, and the highest expression of Connexin-43 in the biphasic group. Subsequently, enriched CM were seeded on the networks of (1) cardiac fibroblasts (FB), (2) D4T endothelial cells (EC), or (3) a mixture of FB and EC that were precultured for 2 days prior to the addition of enriched CM. Biphasic field stimulation was also effective at improving electrical excitability of these cardiac organoids by improving the three-dimensional organization of the cells, increasing cellular elongation and enhancing Connexin-43 presence.

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

    PubMed

    Patel, Yogi A; Butera, Robert J

    2015-06-01

    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.

  7. Study Explores Electrical Brain Stimulation to Treat Bulimia

    MedlinePlus

    ... the brain involved with reward processing and self-regulation. There was also one sham session where the electrode stimulation lasted only 30 seconds. Participants then reported their desire to binge eat, fear of weight gain, general mood and frequency of bulimic behaviors in the 24 hours following ...

  8. Subthreshold electrical stimulation reduces motor unit discharge variability and decreases the force fluctuations of plantar flexion.

    PubMed

    Kouzaki, Motoki; Kimura, Tetsuya; Yoshitake, Yasuhide; Hayashi, Tatsuya; Moritani, Toshio

    2012-04-04

    The purpose of this study was to examine the influence of subthreshold electrical stimulation on the force fluctuations and motor-unit discharge variability during low-level, steady contraction of the plantar flexor muscles. Seven subjects performed a force-matching task of isometric plantar flexion at 5% of maximal voluntary contraction with and without random electrical stimulation applied to the tibial nerve. During the task, the motor unit action potential was continuously recorded with fine-wire electrodes, and the inter-spike intervals of a single motor unit were calculated. The coefficient of variation (CV) of the force fluctuations and the inter-spike intervals of the motor unit discharge were significantly decreased by the intervention of subthreshold electrical stimulation, although there were no changes in the mean values. These results suggest that subthreshold stimulation reduced the motor-unit discharge variability, which in turn, increased the steadiness of the force.

  9. Electrical stimulation by enzymatic biofuel cell to promote proliferation, migration and differentiation of muscle precursor cells.

    PubMed

    Lee, Jae Ho; Jeon, Won-Yong; Kim, Hyug-Han; Lee, Eun-Jung; Kim, Hae-Won

    2015-01-01

    Electrical stimulation is a very important biophysical cue for skeletal muscle maintenance and myotube formation. The absence of electrical signals from motor neurons causes denervated muscles to atrophy. Herein, we investigate for the first time the utility of an enzymatic biofuel cell (EBFC) as a promising means for mimicking native electrical stimulation. EBFC was set up using two different enzymes: one was glucose oxidase (GOX) used for the generation of anodic current followed by the oxidation of glucose; the other was Bilirubin oxidase (BOD) for the generation of cathodic current followed by the reduction of oxygen. We studied the behaviors of muscle precursor cells (MPCs) in terms of proliferation, migration and differentiation under different electrical conditions. The EBFC electrical stimulations significantly increased cell proliferation and migration. Furthermore, the electrical stimulations promoted the differentiation of cells into myotube formation based on expressions at the gene and protein levels. The EBFC set up, with its free forms adjustable to any implant design, was subsequently applied to the nanofiber scaffolding system. The MPCs were demonstrated to be stimulated in a similar manner as the 2D culture conditions, suggesting potential applications of the EBFC system for muscle repair and regeneration.

  10. 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.

  11. Dynamic Impedance Model of the Skin-Electrode Interface for Transcutaneous Electrical Stimulation

    PubMed Central

    Vargas Luna, José Luis; Krenn, Matthias; Cortés Ramírez, Jorge Armando; Mayr, Winfried

    2015-01-01

    Transcutaneous electrical stimulation can depolarize nerve or muscle cells applying impulses through electrodes attached on the skin. For these applications, the electrode-skin impedance is an important factor which influences effectiveness. Various models describe the interface using constant or current-depending resistive-capacitive equivalent circuit. Here, we develop a dynamic impedance model valid for a wide range stimulation intensities. The model considers electroporation and charge-dependent effects to describe the impedance variation, which allows to describe high-charge pulses. The parameters were adjusted based on rectangular, biphasic stimulation pulses generated by a stimulator, providing optionally current or voltage-controlled impulses, and applied through electrodes of different sizes. Both control methods deliver a different electrical field to the tissue, which is constant throughout the impulse duration for current-controlled mode or have a very current peak for voltage-controlled. The results show a predominant dependence in the current intensity in the case of both stimulation techniques that allows to keep a simple model. A verification simulation using the proposed dynamic model shows coefficient of determination of around 0.99 in both stimulation types. The presented method for fitting electrode-skin impedance can be simple extended to other stimulation waveforms and electrode configuration. Therefore, it can be embedded in optimization algorithms for designing electrical stimulation applications even for pulses with high charges and high current spikes. PMID:25942010

  12. Neuromuscular electrical stimulation in critically ill patients in the intensive care unit: a systematic review

    PubMed Central

    Ferreira, Lucas Lima; Vanderlei, Luiz Carlos Marques; Valenti, Vitor Engrácia

    2014-01-01

    Objective To analyze the outcomes enabled by the neuromuscular electric stimulation in critically ill patients in intensive care unit assisted. Methods A systematic review of the literature by means of clinical trials published between 2002 and 2012 in the databases LILACS, SciELO, MEDLINE and PEDro using the descriptors “intensive care unit”, “physical therapy”, “physiotherapy”, “electric stimulation” and “randomized controlled trials”. Results We included four trials. The sample size varied between 8 to 33 individuals of both genders, with ages ranging between 52 and 79 years, undergoing invasive mechanical ventilation. Of the articles analyzed, three showed significant benefits of neuromuscular electrical stimulation in critically ill patients, such as improvement in peripheral muscle strength, exercise capacity, functionality, or loss of thickness of the muscle layer. Conclusion The application of neuromuscular electrical stimulation promotes a beneficial response in critically patients in intensive care. PMID:25295458

  13. Kilohertz frequency nerve block enhances anti-inflammatory effects of vagus nerve stimulation

    PubMed Central

    Patel, Yogi A.; Saxena, Tarun; Bellamkonda, Ravi V.; Butera, Robert J.

    2017-01-01

    Efferent activation of the cervical vagus nerve (cVN) dampens systemic inflammatory processes, potentially modulating a wide-range of inflammatory pathological conditions. In contrast, afferent cVN activation amplifies systemic inflammatory processes, leading to activation of the hypothalamic-pituitary-adrenal (HPA) axis, the sympathetic nervous system through the greater splanchnic nerve (GSN), and elevation of pro-inflammatory cytokines. Ideally, to clinically implement anti-inflammatory therapy via cervical vagus nerve stimulation (cVNS) one should selectively activate the efferent pathway. Unfortunately, current implementations, in animal and clinical investigations, activate both afferent and efferent pathways. We paired cVNS with kilohertz electrical stimulation (KES) nerve block to preferentially activate efferent pathways while blocking afferent pathways. Selective efferent cVNS enhanced the anti-inflammatory effects of cVNS. Our results demonstrate that: (i) afferent, but not efferent, cVNS synchronously activates the GSN in a dose-dependent manner; (ii) efferent cVNS enabled by complete afferent KES nerve block enhances the anti-inflammatory benefits of cVNS; and (iii) incomplete afferent KES nerve block exacerbates systemic inflammation. Overall, these data demonstrate the utility of paired efferent cVNS and afferent KES nerve block for achieving selective efferent cVNS, specifically as it relates to neuromodulation of systemic inflammation. PMID:28054557

  14. Tissue engineering bioreactor systems for applying physical and electrical stimulations to cells.

    PubMed

    Jin, GyuHyun; Yang, Gi-Hoon; Kim, GeunHyung

    2015-05-01

    Bioreactor systems in tissue engineering applications provide various types of stimulation to mimic the tissues in vitro and in vivo. Various bioreactors have been designed to induce high cellular activities, including initial cell attachment, cell growth, and differentiation. Although cell-stimulation processes exert mostly positive effects on cellular responses, in some cases such stimulation can also have a negative effect on cultured cells. In this review, we discuss various types of bioreactor and the positive and negative effects of stimulation (physical, chemical, and electrical) on various cultured cell types.

  15. Magnetic versus electrical stimulation in the interpolation twitch technique of elbow flexors.

    PubMed

    Lampropoulou, Sofia I; Nowicky, Alexander V; Marston, Louise

    2012-01-01

    The study compared peripheral magnetic with electrical stimulation of the biceps brachii m. (BB) in the single pulse Interpolation Twitch Technique (ITT). 14 healthy participants (31±7 years) participated in a within-subjects repeated-measures design study. Single, constant-current electrical and magnetic stimuli were delivered over the motor point of BB with supramaximal intensity (20% above maximum) at rest and at various levels of voluntary contraction. Force measurements from right elbow isometric flexion and muscle electromyograms (EMG) from the BB, the triceps brachii m. (TB) and the abductor pollicis brevis m. (APB) were obtained. The twitch forces at rest and maximal contractions, the twitch force-voluntary force relationship, the M-waves and the voluntary activation (VA) of BB between magnetic and electrical stimulation were compared. The mean amplitude of the twitches evoked at MVC was not significantly different between electrical (0.62 ± 0.49 N) and magnetic (0.81 ± 0.49 N) stimulation (p > 0.05), and the maximum VA of BB was comparable between electrical (95%) and magnetic (93%) stimulation (p > 0. 05). No differences (p >0.05) were revealed in the BB M-waves between electrical (13.47 ± 0.49 mV.ms) and magnetic (12.61 ± 0.58 mV.ms) stimulation. The TB M-waves were also similar (p > 0.05) but electrically evoked APB M-waves were significantly larger than those evoked by magnetic stimulation (p < 0.05). The twitch-voluntary force relationship over the range of MVCs was best described by non-linear functions for both electrical and magnetic stimulation. The electrically evoked resting twitches were consistently larger in amplitude than the magnetically evoked ones (mean difference 3.1 ± 3.34 N, p < 0.05). Reduction of the inter-electrodes distance reduced the twitch amplitude by 6.5 ± 6.2 N (p < 0.05). The fundamental similarities in voluntary activation assessment of BB with peripheral electrical and magnetic stimulation point towards a promising

  16. An electric stimulation system for electrokinetic particle manipulation in microfluidic devices.

    PubMed

    Lopez-de la Fuente, M S; Moncada-Hernandez, H; Perez-Gonzalez, V H; Lapizco-Encinas, B H; Martinez-Chapa, S O

    2013-03-01

    Microfluidic devices have grown significantly in the number of applications. Microfabrication techniques have evolved considerably; however, electric stimulation systems for microdevices have not advanced at the same pace. Electric stimulation of micro-fluidic devices is an important element in particle manipulation research. A flexible stimulation instrument is desired to perform configurable, repeatable, automated, and reliable experiments by allowing users to select the stimulation parameters. The instrument presented here is a configurable and programmable stimulation system for electrokinetic-driven microfluidic devices; it consists of a processor, a memory system, and a user interface to deliver several types of waveforms and stimulation patterns. It has been designed to be a flexible, highly configurable, low power instrument capable of delivering sine, triangle, and sawtooth waveforms with one single frequency or two superimposed frequencies ranging from 0.01 Hz to 40 kHz, and an output voltage of up to 30 Vpp. A specific stimulation pattern can be delivered over a single time period or as a sequence of different signals for different time periods. This stimulation system can be applied as a research tool where manipulation of particles suspended in liquid media is involved, such as biology, medicine, environment, embryology, and genetics. This system has the potential to lead to new schemes for laboratory procedures by allowing application specific and user defined electric stimulation. The development of this device is a step towards portable and programmable instrumentation for electric stimulation on electrokinetic-based microfluidic devices, which are meant to be integrated with lab-on-a-chip devices.

  17. Neurite outgrowth on electrospun PLLA fibers is enhanced by exogenous electrical stimulation

    NASA Astrophysics Data System (ADS)

    Koppes, A. N.; Zaccor, N. W.; Rivet, C. J.; Williams, L. A.; Piselli, J. M.; Gilbert, R. J.; Thompson, D. M.

    2014-08-01

    Objective. Both electrical stimuli (endogenous and exogenous) and topographical cues are instructive to axonal extension. This report, for the first time, investigated the relative dominance of directional topographical guidance cues and directional electrical cues to enhance and/or direct primary neurite extension. We hypothesized the combination of electrical stimulation with electrospun fiber topography would induce longer neurite extension from dorsal root ganglia neurons than the presence of electrical stimulation or aligned topography alone. Approach. To test the hypothesis, neurite outgrowth was examined on laminin-coated poly-L-lactide films or electrospun fibers (2 µm in diameter) in the presence or absence of electrical stimulation. Immunostained neurons were semi-automatically traced using Neurolucida software and morphology was evaluated. Main Results. Neurite extension increased 74% on the aligned fibers compared to film controls. Stimulation alone increased outgrowth by 32% on films or fibers relative to unstimulated film controls. The co-presentation of topographical (fibers) with biophysical (electrical stimulation) cues resulted in a synergistic 126% increase in outgrowth relative to unstimulated film controls. Field polarity had no influence on the directionality of neurites, indicating topographical cues are responsible for guiding neurite extension. Significance. Both cues (electrical stimulation and fiber geometry) are modular in nature and can be synergistically applied in conjunction with other common methods in regenerative medicine such as controlled release of growth factors to further influence axonal growth in vivo. The combined application of electrical and aligned fiber topographical guidance cues described herein, if translated in vivo, could provide a more supportive environment for directed and robust axonal regeneration following peripheral nerve injury.

  18. 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.

  19. [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.

  20. Effect of neuromuscular electrical stimulation on facial muscle strength and oral function in stroke patients with facial palsy

    PubMed Central

    Choi, Jong-Bae

    2016-01-01

    [Purpose] The aim of this study was to investigate the effect of neuromuscular electrical stimulation on facial muscle strength and oral function in stroke patients with facial palsy. [Subjects and Methods] Nine subjects received the electrical stimulation and traditional dysphagia therapy. Electrical stimulation was applied to stimulate each subject’s facial muscles 30 minutes a day, 5 days a week, for 4 weeks. [Results] Subjects showed significant improvement in cheek and lip strength and oral function after the intervention. [Conclusion] This study demonstrates that electrical stimulation improves facial muscle strength and oral function in stroke patients with dysphagia. PMID:27799689

  1. Chronic Spinal Cord Electrical Stimulation Protects Against 6-hydroxydopamine Lesions

    NASA Astrophysics Data System (ADS)

    Yadav, Amol P.; Fuentes, Romulo; Zhang, Hao; Vinholo, Thais; Wang, Chi-Han; Freire, Marco Aurelio M.; Nicolelis, Miguel A. L.

    2014-01-01

    Although L-dopa continues to be the gold standard for treating motor symptoms of Parkinson's disease (PD), it presents long-term complications. Deep brain stimulation is effective, but only a small percentage of idiopathic PD patients are eligible. Based on results in animal models and a handful of patients, dorsal column stimulation (DCS) has been proposed as a potential therapy for PD. To date, the long-term effects of DCS in animal models have not been quantified. Here, we report that DCS applied twice a week in rats treated with bilateral 6-OHDA striatal infusions led to a significant improvement in symptoms. DCS-treated rats exhibited a higher density of dopaminergic innervation in the striatum and higher neuronal cell count in the substantia nigra pars compacta compared to a control group. These results suggest that DCS has a chronic therapeutical and neuroprotective effect, increasing its potential as a new clinical option for treating PD patients.

  2. Epilepsia partialis continua responsive to neocortical electrical stimulation.

    PubMed

    Valentin, Antonio; Ughratdar, Ismail; Cheserem, Beverly; Morris, Robert; Selway, Richard; Alarcon, Gonzalo

    2015-08-01

    Epilepsia partialis continua (EPC), defined as a syndrome of continuous focal jerking, is a rare form of focal status epilepticus that usually affects a distal limb, and when prolonged, can produce long-lasting deficits in limb function. Substantial electrophysiologic evidence links the origin of EPC to the motor cortex; thus surgical resection carries the risk of significant handicap. We present two patients with focal, drug-resistant EPC, who were admitted for intracranial video-electroencephalography monitoring to elucidate the location of the epileptogenic focus and identification of eloquent motor cortex with functional mapping. In both cases, the focus resided at or near eloquent motor cortex and therefore precluded resective surgery. Chronic cortical stimulation delivered through subdural strips at the seizure focus (continuous stimulation at 60-130 Hz, 2-3 mA) resulted in >90% reduction in seizures and abolition of the EPC after a follow-up of 22 months in both patients. Following permanent implantation of cortical stimulators, no adverse effects were noted. EPC restarted when intensity was reduced or batteries depleted. Battery replacement restored previous improvement. This two-case report opens up avenues for the treatment of this debilitating condition.

  3. What does chronic electrical stimulation teach us about muscle plasticity?

    PubMed

    Pette, D; Vrbová, G

    1999-06-01

    The model of chronic low-frequency stimulation for the study of muscle plasticity was developed over 30 years ago. This protocol leads to a transformation of fast, fatigable muscles toward slower, fatigue-resistant ones. It involves qualitative and quantitative changes of all elements of the muscle fiber studied so far. The multitude of stimulation-induced changes makes it possible to establish the full adaptive potential of skeletal muscle. Both functional and structural alterations are caused by orchestrated exchanges of fast protein isoforms with their slow counterparts, as well as by altered levels of expression. This remodeling of the muscle fiber encompasses the major, myofibrillar proteins, membrane-bound and soluble proteins involved in Ca2+ dynamics, and mitochondrial and cytosolic enzymes of energy metabolism. Most transitions occur in a coordinated, time-dependent manner and result from altered gene expression, including transcriptional and posttranscriptional processes. This review summarizes the advantages of chronic low-frequency stimulation for studying activity-induced changes in phenotype, and its potential for investigating regulatory mechanisms of gene expression. The potential clinical relevance or utility of the technique is also considered.

  4. 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.

  5. Chronic Electrical Stimulation with a Suprachoroidal Retinal Prosthesis: A Preclinical Safety and Efficacy Study

    PubMed Central

    Nayagam, David A. X.; Williams, Richard A.; Allen, Penelope J.; Shivdasani, Mohit N.; Luu, Chi D.; Salinas-LaRosa, Cesar M.; Finch, Sue; Ayton, Lauren N.; Saunders, Alexia L.; McPhedran, Michelle; McGowan, Ceara; Villalobos, Joel; Fallon, James B.; Wise, Andrew K.; Yeoh, Jonathan; Xu, Jin; Feng, Helen; Millard, Rodney; McWade, Melanie; Thien, Patrick C.; Williams, Chris E.; Shepherd, Robert K.

    2014-01-01

    Purpose To assess the safety and efficacy of chronic electrical stimulation of the retina with a suprachoroidal visual prosthesis. Methods Seven normally-sighted feline subjects were implanted for 96–143 days with a suprachoroidal electrode array and six were chronically stimulated for 70–105 days at levels that activated the visual cortex. Charge balanced, biphasic, current pulses were delivered to platinum electrodes in a monopolar stimulation mode. Retinal integrity/function and the mechanical stability of the implant were assessed monthly using electroretinography (ERG), optical coherence tomography (OCT) and fundus photography. Electrode impedances were measured weekly and electrically-evoked visual cortex potentials (eEVCPs) were measured monthly to verify that chronic stimuli were suprathreshold. At the end of the chronic stimulation period, thresholds were confirmed with multi-unit recordings from the visual cortex. Randomized, blinded histological assessments were performed by two pathologists to compare the stimulated and non-stimulated retina and adjacent tissue. Results All subjects tolerated the surgical and stimulation procedure with no evidence of discomfort or unexpected adverse outcomes. After an initial post-operative settling period, electrode arrays were mechanically stable. Mean electrode impedances were stable between 11–15 kΩ during the implantation period. Visually-evoked ERGs & OCT were normal, and mean eEVCP thresholds did not substantially differ over time. In 81 of 84 electrode-adjacent tissue samples examined, there were no discernible histopathological differences between stimulated and unstimulated tissue. In the remaining three tissue samples there were minor focal fibroblastic and acute inflammatory responses. Conclusions Chronic suprathreshold electrical stimulation of the retina using a suprachoroidal electrode array evoked a minimal tissue response and no adverse clinical or histological findings. Moreover, thresholds and

  6. Prediction of cortical responses to simultaneous electrical stimulation of the retina

    NASA Astrophysics Data System (ADS)

    Halupka, Kerry J.; Shivdasani, Mohit N.; Cloherty, Shaun L.; Grayden, David B.; Wong, Yan T.; Burkitt, Anthony N.; Meffin, Hamish

    2017-02-01

    Objective. Simultaneous electrical stimulation of multiple electrodes has shown promise in diversifying the responses that can be elicited by retinal prostheses compared to interleaved single electrode stimulation. However, the effects of interactions between electrodes are not well understood and clinical trials with simultaneous stimulation have produced inconsistent results. We investigated the effects of multiple electrode stimulation of the retina by developing a model of cortical responses to retinal stimulation. Approach. Electrical stimuli consisting of temporally sparse, biphasic current pulses, with amplitudes sampled from a bi-dimensional Gaussian distribution, were simultaneously delivered to the retina across a 42-channel electrode array implanted in the suprachoroidal space of anesthetized cats. Visual cortex activity was recorded using penetrating microelectrode arrays. These data were used to identify a linear-nonlinear model of cortical responses to retinal stimulation. The ability of the model to generalize was tested by predicting responses to non-white patterned stimuli. Main results. The model accurately predicted two cortical activity measures: multi-unit neural responses and evoked potential responses to white noise stimuli. The model also provides information about electrical receptive fields, including the relative effects of each stimulating electrode on every recording site. Significance. We have demonstrated a simple model that accurately describes cortical responses to simultaneous stimulation of a suprachoroidal retinal prosthesis. Overall, our results demonstrate that cortical responses to simultaneous multi-electrode stimulation of the retina are repeatable and predictable, and that interactions between electrodes during simultaneous stimulation are predominantly linear. The model shows promise for determining optimal stimulation paradigms for exploiting interactions between electrodes to shape neural activity, thereby improving

  7. Electrically stimulated osteogenesis on Ti-PPy/PLGA constructs prepared by laser-assisted processes.

    PubMed

    Paun, Irina Alexandra; Stokker-Cheregi, Flavian; Luculescu, Catalin Romeo; Acasandrei, Adriana Maria; Ion, Valentin; Zamfirescu, Marian; Mustaciosu, Cosmin Catalin; Mihailescu, Mona; Dinescu, Maria

    2015-10-01

    This work describes a versatile laser-based protocol for fabricating micro-patterned, electrically conductive titanium-polypyrrole/poly(lactic-co-glycolic)acid (Ti-PPy/PLGA) constructs for electrically stimulated (ES) osteogenesis. Ti supports were patterned using fs laser ablation in order to create high spatial resolution microstructures meant to provide mechanical resistance and physical cues for cell growth. Matrix Assisted Pulsed Laser Evaporation (MAPLE) was used to coat the patterned Ti supports with PPy/PLGA layers acting as biocompatible surfaces having chemical and electrical properties suitable for cell differentiation and mineralization. In vitro biological assays on osteoblast-like MG63 cells showed that the constructs maintained cell viability without cytotoxicity. At 24 h after cell seeding, electrical stimulation with currents of 200 μA was applied for 4 h. This treatment was shown to promote earlier onset of osteogenesis. More specifically, the alkaline phosphatase activity of the stimulated cultures reached the maximum before that of the non-stimulated ones, i.e. controls, indicating faster cell differentiation. Moreover, mineralization was found to occur at an earlier stage in the stimulated cultures, as compared to the controls, starting with Day 6 of cell culture. At later stages, calcium levels in the stimulated cultures were higher than those in control samples by about 70%, with Ca/P ratios similar to those of natural bone. In all, the laser-based protocol emerges as an efficient alternative to existing fabrication technologies.

  8. The Effect of Electric Cortical Stimulation after Focal Traumatic Brain Injury in Rats

    PubMed Central

    Yoon, Yong-Soon; Yu, Ki Pi; Kim, Hyojoon; Kim, Hyoung-ihl; Kim, Bong Ok

    2012-01-01

    Objective To evaluate the effects of electric cortical stimulation in the experimentally induced focal traumatic brain injury (TBI) rat model on motor recovery and plasticity of the injured brain. Method Twenty male Sprague-Dawley rats were pre-trained on a single pellet reaching task (SPRT) and on a Rotarod task (RRT) for 14 days. Then, the TBI model was induced by a weight drop device (40 g in weight, 25 cm in height) on the dominant motor cortex, and the electrode was implanted over the perilesional cortical surface. All rats were divided into two groups as follows: Electrical stimulation (ES) group with anodal continuous stimulation (50 Hz and 194 µs duration) or Sham-operated control (SOC) group with no electrical stimulation. The rats were trained SPRT and RRT for 14 days for rehabilitation and measured Garcia's neurologic examination. Histopathological and immunostaining evaluations were performed after the experiment. Results There were no differences in the slice number in the histological analysis. Garcia's neurologic scores & SPRT were significantly increased in the ES group (p<0.05), yet, there was no difference in RRT in both groups. The ES group showed more expression of c-Fos around the brain injured area than the SOC group. Conclusion Electric cortical stimulation with rehabilitation is considered to be one of the trial methods for motor recovery in TBI. However, more studies should be conducted for the TBI model in order to establish better stimulation methods. PMID:23185723

  9. The Neural Correlates of Long-Term Carryover following Functional Electrical Stimulation for Stroke

    PubMed Central

    Gandolla, Marta; Ward, Nick S.; Molteni, Franco; Guanziroli, Eleonora; Ferrigno, Giancarlo; Pedrocchi, Alessandra

    2016-01-01

    Neurorehabilitation effective delivery for stroke is likely to be improved by establishing a mechanistic understanding of how to enhance adaptive plasticity. Functional electrical stimulation is effective at reducing poststroke foot drop; in some patients, the effect persists after therapy has finished with an unknown mechanism. We used fMRI to examine neural correlates of functional electrical stimulation key elements, volitional intent to move and concurrent stimulation, in a group of chronic stroke patients receiving functional electrical stimulation for foot-drop correction. Patients exhibited task-related activation in a complex network, sharing bilateral sensorimotor and supplementary motor activation with age-matched controls. We observed consistent separation of patients with and without carryover effect on the basis of brain responses. Patients who experienced the carryover effect had responses in supplementary motor area that correspond to healthy controls; the interaction between experimental factors in contralateral angular gyrus was seen only in those without carryover. We suggest that the functional electrical stimulation carryover mechanism of action is based on movement prediction and sense of agency/body ownership—the ability of a patient to plan the movement and to perceive the stimulation as a part of his/her own control loop is important for carryover effect to take place. PMID:27073701

  10. Ex Vivo Assay of Electrical Stimulation to Rat Sciatic Nerves: Cell Behaviors and Growth Factor Expression.

    PubMed

    Du, Zhiyong; Bondarenko, Olexandr; Wang, Dingkun; Rouabhia, Mahmoud; Zhang, Ze

    2016-06-01

    Neurite outgrowth and axon regeneration are known to benefit from electrical stimulation. However, how neuritis and their surroundings react to electrical field is difficult to replicate by monolayer cell culture. In this work freshly harvested rat sciatic nerves were cultured and exposed to two types of electrical field, after which time the nerve tissues were immunohistologically stained and the expression of neurotrophic factors and cytokines were evaluated. ELISA assay was used to confirm the production of specific proteins. All cell populations survived the 48 h culture with little necrosis. Electrical stimulation was found to accelerate Wallerian degeneration and help Schwann cells to switch into migratory phenotype. Inductive electrical stimulation was shown to upregulate the secretion of multiple neurotrophic factors. Cellular distribution in nerve tissue was altered upon the application of an electrical field. This work thus presents an ex vivo model to study denervated axon in well controlled electrical field, bridging monolayer cell culture and animal experiment. It also demonstrated the critical role of electrical field distribution in regulating cellular activities.

  11. Effects of electrical stimulation on rat limb regeneration, a new look at an old model

    PubMed Central

    Leppik, Liudmila P.; Froemel, Dara; Slavici, Andrei; Ovadia, Zachri N.; Hudak, Lukasz; Henrich, Dirk; Marzi, Ingo; Barker, John H.

    2015-01-01

    Limb loss is a devastating disability and while current treatments provide aesthetic and functional restoration, they are associated with complications and risks. The optimal solution would be to harness the body’s regenerative capabilities to regrow new limbs. Several methods have been tried to regrow limbs in mammals, but none have succeeded. One such attempt, in the early 1970s, used electrical stimulation and demonstrated partial limb regeneration. Several researchers reproduced these findings, applying low voltage DC electrical stimulation to the stumps of amputated rat forelimbs reporting “blastema, and new bone, bone marrow, cartilage, nerve, skin, muscle and epiphyseal plate formation”. In spite of these encouraging results this research was discontinued. Recently there has been renewed interest in studying electrical stimulation, primarily at a cellular and subcellular level, and studies have demonstrated changes in stem cell behavior with increased proliferation, differentiation, matrix formation and migration, all important in tissue regeneration. We applied electrical stimulation, in vivo, to the stumps of amputated rat limbs and observed significant new bone, cartilage and vessel formation and prevention of neuroma formation. These findings demonstrate that electricity stimulates tissue regeneration and form the basis for further research leading to possible new treatments for regenerating limbs. PMID:26678416

  12. Electric stimulation and decimeter wave therapy improve the recovery of injured sciatic nerves

    PubMed Central

    Zhao, Feng; He, Wei; Zhang, Yingze; Tian, Dehu; Zhao, Hongfang; Yu, Kunlun; Bai, Jiangbo

    2013-01-01

    Drug treatment, electric stimulation and decimeter wave therapy have been shown to promote the repair and regeneration of the peripheral nerves at the injured site. This study prepared a Mackinnon's model of rat sciatic nerve compression. Electric stimulation was given immediately after neurolysis, and decimeter wave radiation was performed at 1 and 12 weeks post-operation. Histological observation revealed that intraoperative electric stimulation and decimeter wave therapy could improve the local blood circulation of repaired sites, alleviate hypoxia of compressed nerves, and lessen adhesion of compressed nerves, thereby decreasing the formation of new entrapments and enhancing compressed nerve regeneration through an improved microenvironment for regeneration. Immunohistochemical staining results revealed that intraoperative electric stimulation and decimeter wave could promote the expression of S-100 protein. Motor nerve conduction velocity and amplitude, the number and diameter of myelinated nerve fibers, and sciatic functional index were significantly increased in the treated rats. These results verified that intraoperative electric stimulation and decimeter wave therapy contributed to the regeneration and the recovery of the functions in the compressed nerves. PMID:25206506

  13. Role of electrical stimulation for rehabilitation and regeneration after spinal cord injury: an overview

    PubMed Central

    Hayek, Ray

    2008-01-01

    Structural discontinuity in the spinal cord after injury results in a disruption in the impulse conduction resulting in loss of various bodily functions depending upon the level of injury. This article presents a summary of the scientific research employing electrical stimulation as a means for anatomical or functional recovery for patients suffering from spinal cord injury. Electrical stimulation in the form of functional electrical stimulation (FES) can help facilitate and improve upper/lower limb mobility along with other body functions lost due to injury e.g. respiratory, sexual, bladder or bowel functions by applying a controlled electrical stimulus to generate contractions and functional movement in the paralysed muscles. The available rehabilitative techniques based on FES technology and various Food and Drug Administration, USA approved neuroprosthetic devices that are in use are discussed. The second part of the article summarises the experimental work done in the past 2 decades to study the effects of weakly applied direct current fields in promoting regeneration of neurites towards the cathode and the new emerging technique of oscillating field stimulation which has shown to promote bidirectional regeneration in the injured nerve fibres. The present article is not intended to be an exhaustive review but rather a summary aiming to highlight these two applications of electrical stimulation and the degree of anatomical/functional recovery associated with these in the field of spinal cord injury research. PMID:18677518

  14. Percutaneous biphasic electrical stimulation for treatment of obstructive sleep apnea syndrome.

    PubMed

    Hu, Lianggang; Xu, Xiaomei; Gong, Yongsheng; Fan, Xiaofang; Wang, Liangxing; Zhang, Jianhua; Zeng, Yanjun

    2008-01-01

    In this paper, we study the effect of stimulation of the genioglossus with percutaneous biphasic electrical pulses on patients with the obstructive sleep apnea syndrome (OSAS). The experiment was conducted in 22 patients clinically diagnosed with OSAS. The patients were monitored with polysomnography (PSG) in the trial. When the sleep apnea was detected, the genioglossus was stimulated with percutaneous biphasic electrical pulses that were automatically regulated by a microcontroller to achieve the optimal effect. The percutaneous biphasic electrical stimulation caused contraction of the genioglossus, forward movement of the tongue, and relieving of the glossopharyngeal airway obstruction. The SaO2, apnea time, hypoxemia time, and change of respiratory disturbance index (RDI) were compared in patients with treatment and without treatment. With percutaneous biphasic electrical stimulation of the genioglossus, the OSAS patients showed apnea time decreased (P < 0.01), RDI decreased (P < 0.01), and SaO2 increased (P < 0.01). No tissue injury or major discomfort was noticed during the trial. The stimulation of genioglossus with percutaneous biphasic electrical current pulse is an effective method for treating OSAS.

  15. The effect of intra-operative transcutaneous electrical nerve stimulation on posterior neck pain following thyroidectomy.

    PubMed

    Park, C; Choi, J B; Lee, Y-S; Chang, H-S; Shin, C S; Kim, S; Han, D W

    2015-04-01

    Posterior neck pain following thyroidectomy is common because full neck extension is required during the procedure. We evaluated the effect of intra-operative transcutaneous electrical nerve stimulation on postoperative neck pain in patients undergoing total thyroidectomy under general anaesthesia. One hundred patients were randomly assigned to one of two groups; 50 patients received transcutaneous electrical nerve stimulation applied to the trapezius muscle and 50 patients acted as controls. Postoperative posterior neck pain and anterior wound pain were evaluated using an 11-point numerical rating scale at 30 min, 6 h, 24 h and 48 h following surgery. The numerical rating scale for posterior neck pain was significantly lower in the transcutaneous electrical nerve stimulation group compared with the control group at all time points (p < 0.05). There were no significant differences in the numerical rating scale for anterior wound pain at any time point. No adverse effects related to transcutaneous electrical nerve stimulation were observed. We conclude that intra-operative transcutaneous electrical nerve stimulation applied to the trapezius muscle reduced posterior neck pain following thyroidectomy.

  16. Influence of air ions on brain activity induced by electrical stimulation in the rat

    NASA Astrophysics Data System (ADS)

    Olivereau, J. M.; Lambert, J. F.; Truong-Ngoc, A.

    1981-03-01

    The brain induced activity was studied in 18 rats wearing chronically skull implanted electrodes. The stimulating factor was various electrical stimulations of the mesencephalic reticular activating formation, given during the slow wave state of sleep. The results of 300 stimulations were measured by amplitude and frequency changes in the EEG simultaneously recorded. Animals previously exposed to positive air ions (3 weeks 80,000 ions/ml) exhibited lowered excitability of the reticulocortical system. Significantly higher stimulations were necessary to induce arousal. Negative air ions induced more intricate effects: brain excitability was lowered when tested with weak stimulations, but normal when evaluated with medium high level stimilations. Sleep seems first more stable but as stimulation increases, arousal is soon as effective as in controls. These results are in agreement with others findings in behavioral fields and partly explains them.

  17. Electric field stimulation setup for photoemission electron microscopes.

    PubMed

    Buzzi, M; Vaz, C A F; Raabe, J; Nolting, F

    2015-08-01

    Manipulating magnetisation by the application of an electric field in magnetoelectric multiferroics represents a timely issue due to the potential applications in low power electronics and the novel physics involved. Thanks to its element sensitivity and high spatial resolution, X-ray photoemission electron microscopy is a uniquely suited technique for the investigation of magnetoelectric coupling in multiferroic materials. In this work, we present a setup that allows for the application of in situ electric and magnetic fields while the sample is analysed in the microscope. As an example of the performances of the setup, we present measurements on Ni/Pb(Mg(0.66)Nb(0.33))O3-PbTiO3 and La(0.7)Sr(0.3)MnO3/PMN-PT artificial multiferroic nanostructures.

  18. Electric field stimulation setup for photoemission electron microscopes

    SciTech Connect

    Buzzi, M.; Vaz, C. A. F.; Raabe, J.; Nolting, F.

    2015-08-15

    Manipulating magnetisation by the application of an electric field in magnetoelectric multiferroics represents a timely issue due to the potential applications in low power electronics and the novel physics involved. Thanks to its element sensitivity and high spatial resolution, X-ray photoemission electron microscopy is a uniquely suited technique for the investigation of magnetoelectric coupling in multiferroic materials. In this work, we present a setup that allows for the application of in situ electric and magnetic fields while the sample is analysed in the microscope. As an example of the performances of the setup, we present measurements on Ni/Pb(Mg{sub 0.66}Nb{sub 0.33})O{sub 3}-PbTiO{sub 3} and La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/PMN-PT artificial multiferroic nanostructures.

  19. Electric field stimulation setup for photoemission electron microscopes

    NASA Astrophysics Data System (ADS)

    Buzzi, M.; Vaz, C. A. F.; Raabe, J.; Nolting, F.

    2015-08-01

    Manipulating magnetisation by the application of an electric field in magnetoelectric multiferroics represents a timely issue due to the potential applications in low power electronics and the novel physics involved. Thanks to its element sensitivity and high spatial resolution, X-ray photoemission electron microscopy is a uniquely suited technique for the investigation of magnetoelectric coupling in multiferroic materials. In this work, we present a setup that allows for the application of in situ electric and magnetic fields while the sample is analysed in the microscope. As an example of the performances of the setup, we present measurements on Ni/Pb(Mg0.66Nb0.33)O3-PbTiO3 and La0.7Sr0.3MnO3/PMN-PT artificial multiferroic nanostructures.

  20. Does electric light stimulate cancer development in children?

    PubMed

    Stevens, Richard G

    2012-05-01

    Incidence of cancer in children has increased in recent decades, and known risk factors can account for only a small minority of cases. Gestation and early childhood are particularly vulnerable periods in human development and an important aspect of development is in circadian rhythmicity. Emerging evidence implicates the molecular circadian mechanism in a vast array of other physiologic functions including metabolism, DNA damage response and cell-cycle regulation. Electric light exposure at night can disrupt circadian rhythms and, thereby, many other physiologic processes that are under circadian control. On this basis, it is proposed that ill-timed electric light exposure to pregnant women, to neonates, infants, and small children may increase cancer risk in those children. There are practical implications and interventions that accrue from this idea should it later be confirmed to be true.

  1. 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.

  2. Non-invasive electric current stimulation for restoration of vision after unilateral occipital stroke.

    PubMed

    Gall, Carolin; Silvennoinen, Katri; Granata, Giuseppe; de Rossi, Francesca; Vecchio, Fabrizio; Brösel, Doreen; Bola, Michał; Sailer, Michael; Waleszczyk, Wioletta J; Rossini, Paolo M; Tatlisumak, Turgut; Sabel, Bernhard A

    2015-07-01

    Occipital stroke often leads to visual field loss, for which no effective treatment exists. Little is known about the potential of non-invasive electric current stimulation to ameliorate visual functions in patients suffering from unilateral occipital stroke. One reason is the traditional thinking that visual field loss after brain lesions is permanent. Since evidence is available documenting vision restoration by means of vision training or non-invasive electric current stimulation future studies should also consider investigating recovery processes after visual cortical strokes. Here, protocols of repetitive transorbital alternating current stimulation (rtACS) and transcranial direct current stimulation (tDCS) are presented and the European consortium for restoration of vision (REVIS) is introduced. Within the consortium different stimulation approaches will be applied to patients with unilateral occipital strokes resulting in homonymous hemianopic visual field defects. The aim of the study is to evaluate effects of current stimulation of the brain on vision parameters, vision-related quality of life, and physiological parameters that allow concluding about the mechanisms of vision restoration. These include EEG-spectra and coherence measures, and visual evoked potentials. The design of stimulation protocols involves an appropriate sham-stimulation condition and sufficient follow-up periods to test whether the effects are stable. This is the first application of non-invasive current stimulation for vision rehabilitation in stroke-related visual field deficits. Positive results of the trials could have far-reaching implications for clinical practice. The ability of non-invasive electrical current brain stimulation to modulate the activity of neuronal networks may have implications for stroke rehabilitation also in the visual domain.

  3. Reduced nitric oxide in the rostral ventrolateral medulla enhances cardiac sympathetic afferent reflex in rats with chronic heart failure.

    PubMed

    Zhu, Guo-Qing; Gao, Xing-Ya; Zhang, Feng; Wang, Wei

    2004-02-25

    The purpose of this study was to determine the effect of nitric oxide (NO) in the rostral ventrolateral medulla (RVLM) on the central integration of the cardiac sympathetic afferent reflex (CSAR) in normal rats and in rats with coronary ligation-induced chronic heart failure (CHF). Under alpha-chloralose and urethane anesthesia, mean arterial pressure, heart rate and renal sympathetic nerve activity (RSNA) were recorded at baseline and during elicitation of the CSAR evoked by electrical stimulation of the cardiac afferent sympathetic nerves in sino-aortic denervated and cervical vagotomized rats. A cannula was inserted into the left RVLM for microinjection of NO synthase inhibitor, S-methyl-L-thiocitruline (MeTC) or NO donor, S-nitroso-N-acetyl-penicillamine (SNAP). The CSAR was tested by electrical stimulation (5, 10, 20 and 30 Hz at 10 V for 1 ms) of the afferent cardiac sympathetic nerves. It was observed that (1) the responses of RSNA to stimulation were enhanced in rats with CHF; (2) MeTC (80 nmol) potentiated the responses of RSNA to stimulation in sham rats but not in rats with CHF; (3) SNAP (50 nmol) depressed the enhanced RSNA response to stimulation in CHF rats but had no effect in sham rats; and (4) MeTC increased the baseline RSNA and MAP only in sham rats, but SNAP inhibited the baseline RSNA and MAP in both sham and CHF rats. These results indicate that reductance of NO in the RVLM is involved in the augmentation of CSAR in CHF rats.

  4. Non-Invasive Electrical Brain Stimulation Montages for Modulation of Human Motor Function.

    PubMed

    Curado, Marco; Fritsch, Brita; Reis, Janine

    2016-02-04

    Non-invasive electrical brain stimulation (NEBS) is used to modulate brain function and behavior, both for research and clinical purposes. In particular, NEBS can be applied transcranially either as direct current stimulation (tDCS) or alternating current stimulation (tACS). These stimulation types exert time-, dose- and in the case of tDCS polarity-specific effects on motor function and skill learning in healthy subjects. Lately, tDCS has been used to augment the therapy of motor disabilities in patients with stroke or movement disorders. This article provides a step-by-step protocol for targeting the primary motor cortex with tDCS and transcranial random noise stimulation (tRNS), a specific form of tACS using an electrical current applied randomly within a pre-defined frequency range. The setup of two different stimulation montages is explained. In both montages the emitting electrode (the anode for tDCS) is placed on the primary motor cortex of interest. For unilateral motor cortex stimulation the receiving electrode is placed on the contralateral forehead while for bilateral motor cortex stimulation the receiving electrode is placed on the opposite primary motor cortex. The advantages and disadvantages of each montage for the modulation of cortical excitability and motor function including learning are discussed, as well as safety, tolerability and blinding aspects.

  5. Effects of sympathetic stimulation on the rhythmical jaw movements produced by electrical stimulation of the cortical masticatory areas of rabbits.

    PubMed

    Roatta, S; Windhorst, U; Djupsjöbacka, M; Lytvynenko, S; Passatore, M

    2005-03-01

    The somatomotor and sympathetic nervous systems are intimately linked. One example is the influence of peripheral sympathetic fibers on the discharge characteristics of muscle spindles. Since muscle spindles play important roles in various motor behaviors, including rhythmic movements, the working hypothesis of this research was that changes in sympathetic outflow to muscle spindles can change rhythmic movement patterns. We tested this hypothesis in the masticatory system of rabbits. Rhythmic jaw movements and EMG activity induced by long-lasting electrical cortical stimulation were powerfully modulated by electrical stimulation of the peripheral stump of the cervical sympathetic nerve (CSN). This modulation manifested itself as a consistent and marked reduction in the excursion of the mandibular movements (often preceded by a transient modest enhancement), which could be attributed mainly to corresponding changes in masseter muscle activity. These changes outlasted the duration of CSN stimulation. In some of the cortically evoked rhythmic jaw movements (CRJMs) changes in masticatory frequency were also observed. When the jaw-closing muscles were subjected to repetitive ramp-and-hold force pulses, the CRMJs changed characteristics. Masseter EMG activity was strongly enhanced and digastric EMG slightly decreased. This change was considerably depressed during CSN stimulation. These effects of CSN stimulation are similar in sign and time course to the depression exerted by sympathetic activity on the jaw-closing muscle spindle discharge. It is suggested that the change in proprioceptive information induced by an increase in sympathetic outflow (a) has important implications even under normal conditions for the control of motor function in states of high sympathetic activity, and (b) is one of the mechanisms responsible for motor impairment under certain pathological conditions such as chronic musculoskeletal head-neck disorders, associated with stress conditions.

  6. The Tulane Electrical Brain Stimulation Program a historical case study in medical ethics.

    PubMed

    Baumeister, A A

    2000-12-01

    In 1950 physicians at Tulane University School of Medicine began a program of research on the use of electrical brain stimulation that would span three decades and involve approximately 100 patients. Initially, electrical brain stimulation was used to treat of schizophrenia, but later it was applied to a variety of other conditions. Throughout its history the Tulane research was well publicized in both the professional and lay literature, and for almost twenty years, with rare exception, these accounts were laudatory. However, in the early 1970s this work began to draw sharp public criticism. Despite its public and controversial nature, the Tulane electrical brain stimulation program has received relatively little attention from historians. This review recounts the history of the Tulane program with particular emphasis on the ethical propriety of the work. Factors that shaped the historical context in which the Tulane experiments were conducted are discussed.

  7. Combining acoustic and electric stimulation in the service of speech recognition

    PubMed Central

    Dorman, Michael F.; Gifford, Rene H.

    2010-01-01

    The majority of recently implanted, cochlear implant patients can potentially benefit from a hearing aid in the ear contralateral to the implant. When patients combine electric and acoustic stimulation, word recognition in quiet and sentence recognition in noise increase significantly. Several studies suggest that the acoustic information that leads to the increased level of performance resides mostly in the frequency region of the voice fundamental, e.g. 125 Hz for a male voice. Recent studies suggest that this information aids speech recognition in noise by improving the recognition of lexical boundaries or word onsets. In some noise environments, patients with bilateral implants can achieve similar levels of performance as patients who combine electric and acoustic stimulation. Patients who have undergone hearing preservation surgery, and who have electric stimulation from a cochlear implant and who have low-frequency hearing in both the implanted and not-implanted ears, achieve the best performance in a high noise environment. PMID:20874053

  8. Electrical stimulation treatment for facial palsy after revision pleomorphic adenoma surgery

    PubMed Central

    Goldie, Simon; Sandeman, Jack; Cole, Richard; Dennis, Simon; Swain, Ian

    2016-01-01

    Surgery for pleomorphic adenoma recurrence presents a significant risk of facial nerve damage that can result in facial weakness effecting patients’ ability to communicate, mental health and self-image. We report two case studies that had marked facial weakness after resection of recurrent pleomorphic adenoma and their progress with electrical stimulation. Subjects received electrical stimulation twice daily for 24 weeks during which photographs of expressions, facial measurements and Sunnybrook scores were recorded. Both subjects recovered good facial function demonstrating Sunnybrook scores of 54 and 64 that improved to 88 and 96, respectively. Neither subjects demonstrated adverse effects of treatment. We conclude that electrical stimulation is a safe treatment and may improve facial palsy in patients after resection of recurrent pleomorphic adenoma. Larger studies would be difficult to pursue due to the low incidence of cases. PMID:27106613

  9. Femoral quadriceps neuromuscular electrical stimulation after total knee arthroplasty: a systematic review

    PubMed Central

    Volpato, Helena Bruna Bettoni; Szego, Paulo; Lenza, Mario; Milan, Silvia Lefone; Talerman, Claudia; Ferretti, Mario

    2016-01-01

    ABSTRACT The purpose of this study was to evaluate the effects of neuromuscular electrical stimulation in patients submitted to total knee arthroplasty. This was a systematic review with no language or publication status restriction. Our search was made in Cochrane Library, MEDLINE, Embase and LILACS. Randomized or quasi-randomized clinical trials evaluating neuromuscular electrical stimulation after total knee arthroplasty were included. Four studies with moderate risk of bias and low statistical power were included, totalizing 376 participants. There was no statistically significant difference in knee function, pain and range of motion during 12 month follow-up. This review concluded that neuromuscular electrical stimulation was less effective than traditional rehabilitation in function, muscular strength and range of motion. However, this technique was useful for quadriceps activation during the first days after surgery. PMID:26537511

  10. The effects of functional electrical stimulation on muscle tone and stiffness of stroke patients

    PubMed Central

    Moon, Sang-Hyun; Choi, Jung-Hyun; Park, Si-Eun

    2017-01-01

    [Purpose] The purpose of this study was to determine the effects of functional electrical stimulation on muscle tone and stiffness in stroke patients. [Subjects and Methods] Ten patients who had suffered from stroke were recruited. The intervention was functional electrical stimulation on ankle dorsiflexor muscle (tibialis anterior). The duration of functional electrical stimulation was 30 minutes, 5 times a week for 6 weeks. The Myoton was used a measure the muscle tone and stiffness of the gastrocnemius muscle (medial and lateral part) on paretic side. [Results] In the assessment of muscle tone, medial and lateral part of gastrocnemius muscle showed differences before and after the experiment. Muscle stiffness of medial gastrocnemius muscle showed differences, and lateral gastrocnemius muscle showed differences before and after the experiment. The changes were greater in stiffness scores than muscle tone. [Conclusion] These results suggest that FES on ankle dorsiflexor muscle had a positive effect on muscle tone and stiffness of stroke patients. PMID:28265148

  11. Direct Electrical Stimulation of the Human Entorhinal Region and Hippocampus Impairs Memory.

    PubMed

    Jacobs, Joshua; Miller, Jonathan; Lee, Sang Ah; Coffey, Tom; Watrous, Andrew J; Sperling, Michael R; Sharan, Ashwini; Worrell, Gregory; Berry, Brent; Lega, Bradley; Jobst, Barbara C; Davis, Kathryn; Gross, Robert E; Sheth, Sameer A; Ezzyat, Youssef; Das, Sandhitsu R; Stein, Joel; Gorniak, Richard; Kahana, Michael J; Rizzuto, Daniel S

    2016-12-07

    Deep brain stimulation (DBS) has shown promise for treating a range of brain disorders and neurological conditions. One recent study showed that DBS in the entorhinal region improved the accuracy of human spatial memory. Based on this line of work, we performed a series of experiments to more fully characterize the effects of DBS in the medial temporal lobe on human memory. Neurosurgical patients with implanted electrodes performed spatial and verbal-episodic memory tasks. During the encoding periods of both tasks, subjects received electrical stimulation at 50 Hz. In contrast to earlier work, electrical stimulation impaired memory performance significantly in both spatial and verbal tasks. Stimulation in both the entorhinal region and hippocampus caused decreased memory performance. These findings indicate that the entorhinal region and hippocampus are causally involved in human memory and suggest that refined methods are needed to use DBS in these regions to improve memory.

  12. A Closed Loop Brain-machine Interface for Epilepsy Control Using Dorsal Column Electrical Stimulation

    PubMed Central

    Pais-Vieira, Miguel; Yadav, Amol P.; Moreira, Derek; Guggenmos, David; Santos, Amílcar; Lebedev, Mikhail; Nicolelis, Miguel A. L.

    2016-01-01

    Although electrical neurostimulation has been proposed as an alternative treatment for drug-resistant cases of epilepsy, current procedures such as deep brain stimulation, vagus, and trigeminal nerve stimulation are effective only in a fraction of the patients. Here we demonstrate a closed loop brain-machine interface that delivers electrical stimulation to the dorsal column (DCS) of the spinal cord to suppress epileptic seizures. Rats were implanted with cortical recording microelectrodes and spinal cord stimulating electrodes, and then injected with pentylenetetrazole to induce seizures. Seizures were detected in real time from cortical local field potentials, after which DCS was applied. This method decreased seizure episode frequency by 44% and seizure duration by 38%. We argue that the therapeutic effect of DCS is related to modulation of cortical theta waves, and propose that this closed-loop interface has the potential to become an effective and semi-invasive treatment for refractory epilepsy and other neurological disorders. PMID:27605389

  13. Activation of retinal ganglion cells following epiretinal electrical stimulation with hexagonally arranged bipolar electrodes

    NASA Astrophysics Data System (ADS)

    Abramian, Miganoosh; Lovell, Nigel H.; Morley, John W.; Suaning, Gregg J.; Dokos, Socrates

    2011-06-01

    We investigated retinal ganglion cell (RGC) responses to epiretinal electrical stimulation delivered by hexagonally arranged bipolar (Hex) electrodes, in order to assess the feasibility of this electrode arrangement for future retinal implant devices. In vitro experiments were performed using rabbit retinal preparations, with results compared to a computational model of axonal stimulation. Single-unit RGC responses to electrical stimulation were recorded with extracellular microelectrodes. With 100 µs/phase biphasic pulses, the threshold charge densities were 24.0 ± 11.2 and 7.7 ± 3.2 µC cm-2 for 50 and 125 µm diameter Hex electrodes, respectively. Threshold profiles and response characteristics strongly suggested that RGC axons were the neural activation site. Both the model and in vitro data indicated that localized tissue stimulation is achieved with Hex electrodes.

  14. Stimulated oxidation of metals (laser, electric field, etc.): Comparative studies

    NASA Astrophysics Data System (ADS)

    Nánai, László; Füle, Miklós

    2014-11-01

    In this report we demonstrate the importance of metal oxides, e.g. thin films and nanostructures, in modern science and technology. The basic laws of oxide thickness on base of diffusion of specimens versus time in different circumstances (Cabrera-Mott and Wagner laws) under the influence of external fields, e.g. electromagnetic field, static electric and magnetic field, are demonstrated. We give experimental results for various metal oxide layers over a wide range of different metals. Theoretical explanations are provided as well for the most reliable circumstances.

  15. TENS (transcutaneous electrical nerve stimulation) for labour pain.

    PubMed

    Francis, Richard

    2012-05-01

    Because TENS is applied inconsistently and not always in line with optimal TENS application theory, this may explain why TENS for labour pain appears to be effective in some individuals and not in others. This article reviews TENS theory, advises upon optimal TENS application for labour pain and discusses some of the limitations of TENS research on labour pain. TENS application for labour pain may include TENS applied to either side of the lower spine, set to 200 mus pulse duration and 100 pulses per second. As pain increases, TENS intensity should be increased and as pain decreases, TENS intensity should be reduced to maintain a strong but pain free intensity of stimulation. This application may particularly reduce back pain during labour.

  16. Meat quality of broiler breast meat following post-mortem electrical stimulation at the neck.

    PubMed

    Owens, C M; Sams, A R

    1998-09-01

    This experiment was conducted to evaluate the effects of electrical stimulation (ES) on breast fillets harvested at 1 h post-mortem and individually quick frozen (IQF) or aged on ice (ICE). Twelve birds were electrically stimulated (450 V, 750 mA, 2 s on/1 s off for 15 s) at the neck in a saline bath. Twenty-four unstimulated birds were used as controls. Breast fillets were harvested at 1 h post-mortem from ES and control carcasses or at 4 h post-mortem from control carcasses and were either IQF or ICE until 24 h post-mortem. Fillets were then analyzed for shear value, pH, R value, and color. Electrical stimulation significantly reduced shear values compared to the 1 h controls for both IQF and ICE treatments. The ICE fillets deboned at 1 h from ES-treated carcasses had shear values similar to those of ICE fillets deboned from the 4 h controls. Electrical stimulation increased the percentage of shear values at or below 8 kg/g for the fillets from ES-treated carcasses compared to the 1 h controls. Electrical stimulation accelerated the normal post-mortem decline in pH and increase in R value. There was no significant difference in L* or a* values between the fillets held for 1 or 24 h. The results suggest that by electrically stimulating carcasses at the neck using a saline bath, the aging period could be eliminated by removing fillets immediately after chilling at 1 h, decreasing the costs associated with aging whole carcasses or front halves.

  17. Therapeutic electric stimulation does not affect immune status in healthy individuals – a preliminary report

    PubMed Central

    2012-01-01

    Background Neuromuscular electric stimulation is widely used for muscle strengthening in clinical practice and for preventative purposes. However, there are few reports on the effects of electric stimulation on the immune response of the organism, and even those mainly describe the changes observed immediately after the electrotherapeutic procedures. The objective of our study was to examine the possible immunological consequences of moderate low-frequency transcutaneous neuromuscular electric stimulation for quadriceps muscle strengthening in healthy individuals. Methods The study included 10 healthy volunteers (5 males, 5 females, mean age 37.5 years). At the beginning and after a two-week electric stimulation program, muscle strength was measured and peripheral blood was collected to analyse white blood cells by flow cytometry for the expression of cell surface antigens (CD3, CD19, CD4, CD8, CD4/8, DR/3, NK, Th reg, CD25 + CD3+, CD25 + CD4+, CD25 + CD8+, CD69 + CD3+, CD69 + CD4+, CD69 + CD8+) and phagocytosis/oxidative killing function. Results Muscle strength slightly increased after the program on the dominant and the nondominant side. No statistically or clinically significant difference was found in any of the measured blood and immune cells parameters as well as phagocytosis and oxidative burst function of neutrophil granulocytes and monocytes one day after the program. Conclusions The program of transcutaneous low-frequency electric stimulation slightly strengthened the quadriceps femoris muscle while producing no changes in measured immunological parameters. Hence, therapeutic low-frequency electric stimulation appears not to be affecting the immune response of healthy persons. PMID:22839574

  18. [Stimulation of longitudinal growth of long bones through electrical current. Scintigraphic examinations on ribbit tibiae].

    PubMed

    Klems, H; Venohr, H; Weigert, M

    1975-01-01

    Report on szintigraphical examinations using 87-mSr in young rabbits treated by direct current of different intensity varying from 2.5 to 40 micro-Ampère. The current was applicated to one tibia using the other as comparison. Corresponding to the realised growth-increase by electric stimulation there was found an increased uptake of 87m-Sr in the electro-stimulated tibia in all 16 rabbits.

  19. Adaptive fuzzy logic restriction rules for error correction and safe stimulation patterns during functional electrical stimulation.

    PubMed

    Hansen, M; Haugland, M K

    2001-01-01

    Adaptive restriction rules based on fuzzy logic have been developed to eliminate errors and to increase stimulation safety in the foot-drop correction application, specifically when using adaptive logic networks to provide a stimulation control signal based on neural activity recorded from peripheral sensory nerve branches. The fuzzy rules were designed to increase flexibility and offer easier customization, compared to earlier versions of restriction rules. The rules developed quantified the duration of swing and stance phases into states of accepting or rejecting new transitions, based on the cyclic nature of gait and statistics on the current gait patterns. The rules were easy to custom design for a specific application, using linguistic terms to model the actions of the rules. The rules were tested using pre-recorded gait data processed through a gait event detector and proved to reduce detection delay and the number of errors, compared to conventional rules.

  20. Auditory Responses to Electric and Infrared Neural Stimulation of the Rat Cochlear Nucleus

    PubMed Central

    Verma, Rohit; Guex, Amelie A.; Hancock, Kenneth E.; Durakovic, Nedim; McKay, Colette M.; Slama, Michaël C. C.; Brown, M. Christian; Lee, Daniel J.

    2014-01-01

    In an effort to improve the auditory brainstem implant, a prosthesis in which user outcomes are modest, we applied electric and infrared neural stimulation (INS) to the cochlear nucleus in a rat animal model. Electric stimulation evoked regions of neural activation in the inferior colliculus and short-latency, multipeaked auditory brainstem responses (ABRs). Pulsed INS, delivered to the surface of the cochlear nucleus via an optical fiber, evoked broad neural activation in the inferior colliculus. Strongest responses were recorded when the fiber was placed at lateral positions on the cochlear nucleus, close to the temporal bone. INS-evoked ABRs were multipeaked but longer in latency than those for electric stimulation; they resembled the responses to acoustic stimulation. After deafening, responses to electric stimulation persisted, whereas those to INS disappeared, consistent with a reported “optophonic” effect, a laser-induced acoustic artifact. Thus, for deaf individuals who use the auditory brainstem implant, INS alone did not appear promising as a new approach. PMID:24508368

  1. Effects of electrical stimulation on House-Brackmann scores in early Bell's palsy.

    PubMed

    Alakram, Prisha; Puckree, Threethambal

    2010-04-22

    ABSTRACT Limited evidence may support the application of electrical stimulation in the subacute and chronic stages of facial palsy, yet some physiotherapists in South Africa have been applying this modality in the acute stage in the absence of published evidence of clinical efficacy. This preliminary study's aim was to determine the safety and potential efficacy of applying electrical stimulation to the facial muscles during the early phase of Bells palsy. A pretest posttest control vs. experimental groups design composed of 16 patients with Bell's palsy of less than 30 days' duration. Adult patients with clinical diagnosis of Bell's palsy were systematically (every second patient) allocated to the control and experimental groups. Each group (n = 8) was pretested and posttested using the House-Brackmann index. Both groups were treated with heat, massage, exercises, and a home program. The experimental group also received electrical stimulation. The House-Brackmann Scale of the control group improved between 17% and 50% with a mean of 30%. The scores of the experimental group ranged between 17% and 75% with a mean of 37%. The difference between the groups was not statistically significant (two-tailed p = 0.36). Electrical stimulation as used in this study during the acute phase of Bell's palsy is safe but may not have added value over spontaneous recovery and multimodal physiotherapy. A larger sample size or longer stimulation time or both should be investigated.

  2. Relationship between neural activation and electric field distribution during deep brain stimulation.

    PubMed

    Åström, Mattias; Diczfalusy, Elin; Martens, Hubert; Wårdell, Karin

    2015-02-01

    Models and simulations are commonly used to study deep brain stimulation (DBS). Simulated stimulation fields are often defined and visualized by electric field isolevels or volumes of tissue activated (VTA). The aim of the present study was to evaluate the relationship between stimulation field strength as defined by the electric potential V, the electric field E, and the divergence of the electric field ∇(2) V, and neural activation. Axon cable models were developed and coupled to finite-element DBS models in three-dimensional (3-D). Field thresholds ( VT , ET, and ∇(2) VT ) were derived at the location of activation for various stimulation amplitudes (1 to 5 V), pulse widths (30 to 120 μs), and axon diameters (2.0 to 7.5 μm). Results showed that thresholds for VT and ∇(2) VT were highly dependent on the stimulation amplitude while ET were approximately independent of the amplitude for large axons. The activation field strength thresholds presented in this study may be used in future studies to approximate the VTA during model-based investigations of DBS without the need of computational axon models.

  3. Effect of oscillating electrical field stimulation on motor function recovery and myelin regeneration after spinal cord injury in rats.

    PubMed

    Tian, Da-Sheng; Jing, Jue-Hua; Qian, Jun; Chen, Lei; Zhu, Bin

    2016-05-01

    [Purpose] The aim of this study was to evaluate the effect of oscillating electrical field stimulation on motor function recovery and myelin regeneration in rats with spinal cord injury. [Subjects and Methods] A rat model of spinal cord injury was constructed by using the Allen weight-drop method. These rats were randomly divided into normal, spinal cord injury, and spinal cord injury + oscillating electrical field stimulation groups. The experimental group received the intervention with oscillating electrical field stimulation, and the control group received the intervention with an electrical field stimulator without oscillating electrical field stimulation. Each group was then randomly divided into seven subgroups according to observation time (1, 2, 4, 6, 8, 10, and 12 weeks). Basso-Beattie-Bresnahan score and inclined plate test score evaluation, motor evoked potential detection, and histological observation were performed. [Results] In the first 2 weeks of oscillating electrical field stimulation, the oscillating electrical field stimulation and inclined plate test scores of spinal cord injury group and spinal cord injury + oscillating electrical field stimulation group were not significantly different. In the fourth week, the scores of the spinal cord injury group were significantly lower than those of the spinal cord injury + oscillating electrical field stimulation group. The motor evoked potential incubation period in the spinal cord injury + oscillating electrical field stimulation group at the various time points was shorter than that in the spinal cord injury group. In the sixth week, the relative area of myelin in the spinal cord injury + oscillating electrical field stimulation group was evidently larger than that in the spinal cord injury group. [Conclusion] Oscillating electrical field stimulation could effectively improve spinal cord conduction function and promote motor function recovery in rats with spinal cord injury, as well as promote myelin

  4. Wireless electrical stimulation: an innovative powerful tool for the treatment of a complicated chronic ulcer.

    PubMed

    Castana, Ourania; Dimitrouli, Aekaterini; Argyrakos, Theodoros; Theodorakopoulou, Emilia; Stampolidis, Nektarios; Papadopoulos, Emmanouil; Pallantzas, Athanasios; Stasinopoulos, Ioannis; Poulas, Konstantinos

    2013-03-01

    High-voltage electrical stimulation has been long proposed as a method of accelerating the wound healing process. Its beneficial effect has been successfully evaluated in the treatment of a number of chronic ulcers and burns. We present here the implementation of a new wireless electrical stimulation technique for the treatment of a complicated chronic ulcer of the lower limb. The device is transferring charges to the wound, without any contact with it, creating a microcurrent that is able to generate the current of injury. The results suggest that this easy-to-use method is an effective therapeutic option for chronic ulcers.

  5. Emerging subspecialties in neurology: deep brain stimulation and electrical neuro-network modulation.

    PubMed

    Hassan, Anhar; Okun, Michael S

    2013-01-29

    Deep brain stimulation (DBS) is a surgical therapy that involves the delivery of an electrical current to one or more brain targets. This technology has been rapidly expanding to address movement, neuropsychiatric, and other disorders. The evolution of DBS has created a niche for neurologists, both in the operating room and in the clinic. Since DBS is not always deep, not always brain, and not always simply stimulation, a more accurate term for this field may be electrical neuro-network modulation (ENM). Fellowships will likely in future years evolve their scope to include other technologies, and other nervous system regions beyond typical DBS therapy.

  6. Electrical stimulation of the starfish's radial nerve in vitro induces the release of a gonadotrophin.

    PubMed

    DeSantis, M; Cloud, J G

    1984-09-01

    In starfish a neuropeptide responsible for the induction of ovulation and the reinitiation of meiotic maturation in fully grown oocytes appears to be released from the radial nerves at the time of spawning. The objectives of this investigation were to determine if the radial nerve would release this gonadotrophin when electrically stimulated in vitro and to locate other possible sources of this factor. Electrical stimulation of radial nerves isolated from the starfish, Pycnopodia helianthoides, resulted in the release of the gonadotrophin. Significant amounts of this neuropeptide were detected neither in other tissues of the starfish nor in mammalian nervous tissue.

  7. [Treatment of congenital facial paralysis with crossed innervation of facial nerve and electric field stimulation].

    PubMed

    Ysunza-Rivera, A; Iñigo-Muñoz, F; Drucker-Colín, R; Ortiz-Monasterio, F; Pesqueira, T

    1992-04-01

    Congenital facial palsy is a devastating deformity. At present time there are no reports of the early treatment of this disorder. The treatment may be to supply contralateral auto reinnervation to the affected muscles through a sural-facial nerve graft enhanced by electric field stimulation. The purpose of this paper is to report 5 cases of congenital facial palsy treated by a crossed sural-facial nerve graft, enhanced by electric field stimulation. One year after surgery, clinical and electrodiagnostic examinations indicate appropriate reinnervation activity in all the patients.

  8. Delay-Dependent Response in Weakly Electric Fish under Closed-Loop Pulse Stimulation

    PubMed Central

    Forlim, Caroline Garcia; Pinto, Reynaldo Daniel; Varona, Pablo; Rodríguez, Francisco B.

    2015-01-01

    In this paper, we apply a real time activity-dependent protocol to study how freely swimming weakly electric fish produce and process the timing of their own electric signals. Specifically, we address this study in the elephant fish, Gnathonemus petersii, an animal that uses weak discharges to locate obstacles or food while navigating, as well as for electro-communication with conspecifics. To investigate how the inter pulse intervals vary in response to external stimuli, we compare the response to a simple closed-loop stimulation protocol and the signals generated without electrical stimulation. The activity-dependent stimulation protocol explores different stimulus delivery delays relative to the fish’s own electric discharges. We show that there is a critical time delay in this closed-loop interaction, as the largest changes in inter pulse intervals occur when the stimulation delay is below 100 ms. We also discuss the implications of these findings in the context of information processing in weakly electric fish. PMID:26473597

  9. Manual and Electrical Needle Stimulation in Acupuncture Research: Pitfalls and Challenges of Heterogeneity

    PubMed Central

    Schnyer, Rosa; MacPherson, Hugh; Davis, Robert; Harris, Richard E.; Napadow, Vitaly; Wayne, Peter M.; Milley, Ryan J.; Lao, Lixing; Stener-Victorin, Elisabet; Kong, Jiang-Ti; Hammerschlag, Richard

    2015-01-01

    Abstract In the field of acupuncture research there is an implicit yet unexplored assumption that the evidence on manual and electrical stimulation techniques, derived from basic science studies, clinical trials, systematic reviews, and meta-analyses, is generally interchangeable. Such interchangeability would justify a bidirectional approach to acupuncture research, where basic science studies and clinical trials each inform the other. This article examines the validity of this fundamental assumption by critically reviewing the literature and comparing manual to electrical acupuncture in basic science studies, clinical trials, and meta-analyses. The evidence from this study does not support the assumption that these techniques are interchangeable. This article also identifies endemic methodologic limitations that have impaired progress in the field. For example, basic science studies have not matched the frequency and duration of manual needle stimulation to the frequency and duration of electrical stimulation. Further, most clinical trials purporting to compare the two types of stimulation have instead tested electroacupuncture as an adjunct to manual acupuncture. The current findings reveal fundamental gaps in the understanding of the mechanisms and relative effectiveness of manual versus electrical acupuncture. Finally, future research directions are suggested to better differentiate electrical from manual simulation, and implications for clinical practice are discussed. PMID:25710206

  10. An investigation into the induced electric fields from transcranial magnetic stimulation

    NASA Astrophysics Data System (ADS)

    Hadimani, Ravi; Lee, Erik; Duffy, Walter; Waris, Mohammed; Siddiqui, Waquar; Islam, Faisal; Rajamani, Mahesh; Nathan, Ryan; Jiles, David; David C Jiles Team; Walter Duffy Collaboration

    Transcranial magnetic stimulation (TMS) is a promising tool for noninvasive brain stimulation that has been approved by the FDA for the treatment of major depressive disorder. To stimulate the brain, TMS uses large, transient pulses of magnetic field to induce an electric field in the head. This transient magnetic field is large enough to cause the depolarization of cortical neurons and initiate a synaptic signal transmission. For this study, 50 unique head models were created from MRI images. Previous simulation studies have primarily used a single head model, and thus give a limited image of the induced electric field from TMS. This study uses finite element analysis simulations on 50 unique, heterogeneous head models to better investigate the relationship between TMS and the electric field induced in brain tissues. Results showed a significant variation in the strength of the induced electric field in the brain, which can be reasonably predicted by the distance from the TMS coil to the stimulated brain. Further, it was seen that some models had high electric field intensities in over five times as much brain volume as other models.

  11. Enhancement of bacterial denitrification for nitrate removal in groundwater with electrical stimulation from microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Zhang, Baogang; Liu, Ye; Tong, Shuang; Zheng, Maosheng; Zhao, Yinxin; Tian, Caixing; Liu, Hengyuan; Feng, Chuanping

    2014-12-01

    Electricity generated from the microbial fuel cell (MFC) is applied to the bioelectrical reactor (BER) directly as electrical stimulation means for enhancement of bacterial denitrification to remove nitrate effectively from groundwater. With maximum power density of 502.5 mW m-2 and voltage outputs ranging from 500 mV to 700 mV, the nitrate removal is accelerated, with less intermediates accumulation, compared with control sets without electrical stimulation. Denitrification bacteria proliferations and activities are promoted as its number and Adenosine-5'-triphosphate (ATP) concentration increased one order of magnitude (3.5 × 107 in per milliliter biofilm solution) and about 1.5 folds, respectively. Effects of electricity from MFCs on enhancement of bacterial behaviors are demonstrated for the first time. These results indicate that MFCs can be applied in the in-situ bioremediation of nitrate polluted groundwater for efficiency improvement.

  12. Magneto-Electric Nano-Particles for Non-Invasive Brain Stimulation

    PubMed Central

    Yue, Kun; Guduru, Rakesh; Hong, Jeongmin; Liang, Ping; Nair, Madhavan; Khizroev, Sakhrat

    2012-01-01

    This paper for the first time discusses a computational study of using magneto-electric (ME) nanoparticles to artificially stimulate the neural activity deep in the brain. The new technology provides a unique way to couple electric signals in the neural network to the magnetic dipoles in the nanoparticles with the purpose to enable a non-invasive approach. Simulations of the effect of ME nanoparticles for non-invasively stimulating the brain of a patient with Parkinson's Disease to bring the pulsed sequences of the electric field to the levels comparable to those of healthy people show that the optimized values for the concentration of the 20-nm nanoparticles (with the magneto-electric (ME) coefficient of 100 V cm−1 Oe−1 in the aqueous solution) is 3×106 particles/cc, and the frequency of the externally applied 300-Oe magnetic field is 80 Hz. PMID:22957042

  13. Differential changes in gingival somatosensory sensitivity after painful electrical tooth stimulation.

    PubMed

    Baad-Hansen, Lene; Lu, Shengyi; Kemppainen, Pentti; List, Thomas; Zhang, Zhenting; Svensson, Peter

    2015-04-01

    We aimed to evaluate the effect of painful tooth stimulation on gingival somatosensory sensitivity of healthy volunteers in a randomized, controlled design. Thirteen healthy volunteers (six women, seven men; 28.4 ± 5.0 years) were included for two experimental sessions of electrical tooth stimulation: painful tooth stimulation and tooth stimulation below the sensory threshold (control). Eight of the human subjects participated in a third session without tooth stimulation. In all sessions, the somatosensory sensitivity of the gingiva adjacent to the stimulated tooth was evaluated with a standardized battery of quantitative sensory tests (QST) before, immediately after and 30 min after tooth stimulation. Painful tooth stimulation evoked significant decreases in warmth and heat pain thresholds (P < 0.001) as well as pressure pain thresholds (increased sensitivity) (P = 0.024) and increases in mechanical detection thresholds (decreased sensitivity) (P < 0.050). Similar thermal threshold changes (P < 0.019) but no mechanical changes were found after tooth stimulation below the sensory threshold (P > 0.086). No QST changes were detected in the session without tooth stimulation (P > 0.060). In conclusion, modest increased gingival sensitivity to warmth, painful heat and pressure stimuli as well as desensitization to non-painful mechanical stimulation were demonstrated after tooth stimulation. This suggests involvement of competing heterotopic facilitatory and inhibitory mechanisms. Furthermore, stimulation below the sensory threshold induced similar thermal sensitization suggesting the possibility of activation of axon-reflex-like mechanisms even at intensities below the perception threshold. These findings may have implications for interpretation of somatosensory results in patients with chronic intraoral pain.

  14. Cell stimulation and calcium mobilization by picosecond electric pulses.

    PubMed

    Semenov, Iurii; Xiao, Shu; Kang, Dongkoo; Schoenbach, Karl H; Pakhomov, Andrei G

    2015-10-01

    We tested if picosecond electric pulses (psEP; 190 kV/cm, 500 ps at 50% height), which are much shorter than channel activation time, can activate voltage-gated (VG) channels. Cytosolic Ca(2+) was monitored by Fura-2 ratiometric imaging in GH3 and NG108 cells (which express multiple types of VG calcium channels, VGCC), and in CHO cells (which express no VGCC). Trains of up to 100 psEP at 1 kHz elicited no response in CHO cells. However, even a single psEP significantly increased Ca(2+) in both GH3 (by 114 ± 48 nM) and NG108 cells (by 6 ± 1.1 nM). Trains of 100 psEP amplified the response to 379 ± 33 nM and 719 ± 315 nM, respectively. Ca(2+) responses peaked within 2-15s and recovered for over 100 s; they were 80-100% inhibited by verapamil and ω-conotoxin, but not by the substitution of Na(+) with N-methyl-D-glucamine. There was no response to psEP in Ca(2+)-free medium, but adding external Ca(2+) even 10s later evoked Ca(2+) response. We conclude that electrical stimuli as short as 500 ps can cause long-lasting opening of VGCC by a mechanism which does not involve conventional electroporation, heating (which was under 0.06 K per psEP), or membrane depolarization by opening of VG Na(+) channels.

  15. Mandarin Speech Perception in Combined Electric and Acoustic Stimulation

    PubMed Central

    Li, Yongxin; Zhang, Guoping; Galvin, John J.; Fu, Qian-Jie

    2014-01-01

    For deaf individuals with residual low-frequency acoustic hearing, combined use of a cochlear implant (CI) and hearing aid (HA) typically provides better speech understanding than with either device alone. Because of coarse spectral resolution, CIs do not provide fundamental frequency (F0) information that contributes to understanding of tonal languages such as Mandarin Chinese. The HA can provide good representation of F0 and, depending on the range of aided acoustic hearing, first and second formant (F1 and F2) information. In this study, Mandarin tone, vowel, and consonant recognition in quiet and noise was measured in 12 adult Mandarin-speaking bimodal listeners with the CI-only and with the CI+HA. Tone recognition was significantly better with the CI+HA in noise, but not in quiet. Vowel recognition was significantly better with the CI+HA in quiet, but not in noise. There was no significant difference in consonant recognition between the CI-only and the CI+HA in quiet or in noise. There was a wide range in bimodal benefit, with improvements often greater than 20 percentage points in some tests and conditions. The bimodal benefit was compared to CI subjects’ HA-aided pure-tone average (PTA) thresholds between 250 and 2000 Hz; subjects were divided into two groups: “better” PTA (<50 dB HL) or “poorer” PTA (>50 dB HL). The bimodal benefit differed significantly between groups only for consonant recognition. The bimodal benefit for tone recognition in quiet was significantly correlated with CI experience, suggesting that bimodal CI users learn to better combine low-frequency spectro-temporal information from acoustic hearing with temporal envelope information from electric hearing. Given the small number of subjects in this study (n = 12), further research with Chinese bimodal listeners may provide more information regarding the contribution of acoustic and electric hearing to tonal language perception. PMID:25386962

  16. Cell stimulation and calcium mobilization by picosecond electric pulses

    PubMed Central

    Semenov, Iurii; Xiao, Shu; Kang, Dongkoo; Schoenbach, Karl H.; Pakhomov, Andrei G.

    2015-01-01

    We tested if picosecond electric pulses (psEP; 190 kV/cm, 500 ps at 50% height), which are much shorter than channel activation time, can activate voltage-gated (VG) channels. Cytosolic Ca2+ was monitored by Fura-2 ratiometric imaging in GH3 and NG108 cells (which express multiple types of VG calcium channels, VGCC), and in CHO cells (which express no VGCC). Trains of up to 100 psEP at 1 kHz elicited no response in CHO cells. However, even a single psEP significantly increased Ca2+ in both GH3 (by 114+/−48 nM) and NG108 cells (by 6 +/−1.1 nM). Trains of 100 psEP amplified the response to 379+/−33 nM and 719+/−315 nM, respectively. Ca2+ responses peaked within 2–15 s and recovered for over 100 s; they were 80–100% inhibited by verapamil and ω-conotoxin, but not by the substitution of Na+ with N-methyl-D-glucamine. There was no response to psEP in Ca2+-free medium, but adding external Ca2+ even 10 s later evoked Ca2+ response. We conclude that electrical stimuli as short as 500 ps can cause long-lasting opening of VGCC by a mechanism which does not involve conventional electroporation, heating (which was under 0.06 °K per psEP), or membrane depolarization by opening of VG Na+ channels. PMID:26011130

  17. Short time effect of Delta oscillation under microcurrent transcutaneous electrical nerve stimulation at ST36.

    PubMed

    Li, Shunan; Li, Donghui; Li, Huiyan; Wang, Jiang

    2014-01-01

    This paper was to study the short time effect of Delta brain oscillation under microcurrent transcutaneous electrical nerve stimulation (MTENS) at ST36 (Zusanli). The 64-channal electroencephalograph (EEG) signals from 12 healthy volunteers were recorded including baseline stage, during stimulation and after stimulation. Autoregressive (AR) Burg method was used to estimate the power spectrum. Then power variation rate (PVR) was calculated to quantify the effects compared with the baseline in Delta band. The results showed that MTENS at ST36 on right side led to increased Delta band power in left frontal.

  18. Power Strategy in DC/DC Converters to Increase Efficiency of Electrical Stimulators.

    PubMed

    Aqueveque, Pablo; Acuña, Vicente; Saavedra, Francisco; Debelle, Adrien; Lonys, Laurent; Julémont, Nicolas; Huberland, François; Godfraind, Carmen; Nonclercq, Antoine

    2016-06-13

    Power efficiency is critical for electrical stimulators. Battery life of wearable stimulators and wireless power transmission in implanted systems are common limiting factors. Boost DC/DC converters are typically needed to increase the supply voltage of the output stage. Traditionally, boost DC/DC converters are used with fast control to regulate the supply voltage of the output. However, since stimulators are acting as current sources, such voltage regulation is not needed. Banking on this, this paper presents a DC/DC conversion strategy aiming to increase power efficiency. It compares, in terms of efficiency, the traditional use of boost converters to two alternatives that could be implemented in future hardware designs.

  19. The influence of pain on masseter spindle afferent discharge.

    PubMed

    Capra, Norman F; Hisley, Calvin K; Masri, Radi M

    2007-04-01

    Muscle spindles provide proprioceptive feedback supporting normal patterns of motor activity and kinesthetic sensibility. During mastication, jaw muscle spindles play an important role in monitoring and regulating the chewing cycle and the bite forces generated during mastication. Both acute and chronic orofacial pain disorders are associated with changes in proprioceptive feedback and motor function. Experimental jaw muscle pain also alters the normal response of masseter spindle afferents to ramp and hold jaw movements. It has been proposed that altered motor function and proprioceptive input results from group III muscle afferent modulation of the fusimotor system which alters spindle afferent sensitivity in limb muscles. The response to nociceptive stimuli may enhance or reduce the response of spindle afferents to proprioceptive stimuli. Several experimental observations suggesting the possibility that a similar mechanism also functions in jaw muscles are presented in this report. First, evidence is provided to show that nociceptive stimulation of the masseter muscle primarily influences the amplitude sensitivity of spindle afferents with relatively little effect on the dynamic sensitivity. Second, reversible inactivation of the caudal trigeminal nuclei attenuates the nociceptive modulation of spindle afferents. Finally, functionally identified gamma-motoneurons in the trigeminal motor nucleus are modulated by intramuscular injection with algesic substances. Taken together, these results suggest that pain-induced modulation of spindle afferent responses are mediated by small diameter muscle afferents and that this modulation is dependent, in part, on the relay of muscle nociceptive information from trigeminal subnucleus caudalis onto trigeminal gamma-motoneurons. The implication of these results will be considered in light of current theories on the relationship between jaw muscle pain and oral motor function.

  20. Cholinergic modulation of primary afferent glutamatergic transmission in rat medullary dorsal horn neurons.

    PubMed

    Jeong, Seok-Gwon; Choi, In-Sun; Cho, Jin-Hwa; Jang, Il-Sung

    2013-12-01

    Although muscarinic acetylcholine (mACh) receptors are expressed in trigeminal ganglia, it is still unknown whether mACh receptors modulate glutamatergic transmission from primary afferents onto medullary dorsal horn neurons. In this study, we have addressed the cholinergic modulation of primary afferent glutamatergic transmission using a conventional whole cell patch clamp technique. Glutamatergic excitatory postsynaptic currents (EPSCs) were evoked from primary afferents by electrical stimulation of trigeminal tract and monosynaptic EPSCs were recorded from medullary dorsal horn neurons of rat horizontal brain stem slices. Muscarine and ACh reversibly and concentration-dependently decreased the amplitude of glutamatergic EPSCs and increased the paired-pulse ratio. In addition, muscarine reduced the frequency of miniature EPSCs without affecting the current amplitude, suggesting that muscarine acts presynaptically to decrease the probability of glutamate release onto medullary dorsal horn neurons. The muscarine-induced decrease of glutamatergic EPSCs was significantly occluded by methoctramine or AF-DX116, M2 receptor antagonists, but not pirenzepine, J104129 and MT-3, selective M1, M3 and M4 receptor antagonists. The muscarine-induced decrease of glutamatergic EPSCs was highly dependent on the extracellular Ca2+ concentration. Physostigmine and clinically available acetylcholinesterase inhibitors, such as rivastigmine and donepezil, significantly shifted the concentration-inhibition relationship of ACh for glutamatergic EPSCs. These results suggest that muscarine acts on presynaptic M2 receptors to inhibit glutamatergic transmission by reducing the Ca2+ influx into primary afferent terminals, and that M2 receptor agonists and acetylcholinesterase inhibitors could be, at least, potential targets to reduce nociceptive transmission from orofacial tissues.

  1. Vagus Nerve Stimulation.

    PubMed

    Howland, Robert H

    2014-06-01

    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.

  2. 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

  3. A novel numerical meshless approach for electric potential estimation in transcranial stimulation

    NASA Astrophysics Data System (ADS)

    Ala, Guido; Fasshauer, Gregory E.; Francomano, Elisa; Ganci, Salvatore; McCourt, Michael J.; Vitabile, Salvatore

    2015-12-01

    In this paper, a first application of the method of fundamental solutions in estimating the electric potential and the spatial current density distribution in the brain due to transcranial stimulation, is presented. The coupled boundary value p roblems for the electric potential are solved in a meshless way, so avoiding the use of grid based numerical methods. A multi-spherical geometry is considered and numerical results are discussed.

  4. Technical aspects of neurostimulation: Focus on equipment, electric field modeling, and stimulation protocols.

    PubMed

    Klooster, D C W; de Louw, A J A; Aldenkamp, A P; Besseling, R M H; Mestrom, R M C; Carrette, S; Zinger, S; Bergmans, J W M; Mess, W H; Vonck, K; Carrette, E; Breuer, L E M; Bernas, A; Tijhuis, A G; Boon, P

    2016-06-01

    Neuromodulation is a field of science, medicine, and bioengineering that encompasses implantable and non-implantable technologies for the purpose of improving quality of life and functioning of humans. Brain neuromodulation involves different neurostimulation techniques: transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), vagus nerve stimulation (VNS), and deep brain stimulation (DBS), which are being used both to study their effects on cognitive brain function