Frequency Electrical Stimulation Research Articles

Engineering an in vitro retinothalamic nerve model

Understanding the retinogeniculate pathway in vitro can offer insights into its development and potential for future therapeutic applications. This study presents a Polydimethylsiloxane-based two-chamber system with axon guidance channels, designed to replicate unidirectional retinogeniculate signal transmission in vitro. Using embryonic rat retinas, we developed a model where retinal spheroids innervate thalamic targets through up to 6 mm long microfluidic channels. Using a combination of electrical stimulation and functional calcium imaging we assessed how channel length and electrical stimulation frequency affects thalamic target response. In the presented model we integrated up to 20 identical functional retinothalamic neural networks aligned on a single transparent microelectrode array, enhancing the robustness and quality of recorded functional data. We found that network integrity depends on channel length, with 0.5–2 mm channels maintaining over 90% morphological and 50% functional integrity. A reduced network integrity was recorded in longer channels. The results indicate a notable reduction in forward spike propagation in channels longer than 4 mm. Additionally, spike conduction fidelity decreased with increasing channel length. Yet, stimulation-induced thalamic target activity remained unaffected by channel length. Finally, the study found that a sustained thalamic calcium response could be elicited with stimulation frequencies up to 31 Hz, with higher frequencies leading to transient responses. In conclusion, this study presents a high-throughput platform that demonstrates how channel length affects retina to brain network formation and signal transmission in vitro.

Usage Frequency, Barriers, And Effectiveness of Functional Electrical Stimulation as An Intervention for Stroke Patients

Objective: To determine the frequency of Functional Electrical Stimulation (FES) use in stroke rehabilitation and to identify the barriers and effectiveness of its usage as an intervention for stroke patients. Materials & Methods: This prospective observational study was performed in different clinics and hospitals in Hyderabad. Physical therapists actively practicing in healthcare facilities within Hyderabad, with a minimum of one year of clinical experience in stroke rehabilitation of either gender were included. A questionnaire was structured to collect data on the usage frequency, perceived barriers, and effectiveness related to the utilization of FES in stroke rehabilitation. Results: Most of the participants were using FES frequently and sometimes for shoulder subluxation, improving arm function, enhancing walking function, improving muscle strength and endurance, addressing hypertonia and spasticity, and improving sensation. Respondents when asked about having sufficient time to apply FES, lack of evidence justifying FES use, and regards to workplace support most of the cases >50% agreed strongly agreed, while <50% of study subjects’ believed that does not provide advantages for individuals having a chronic stroke. FES utilization among healthcare professionals in stroke patient rehabilitation, highlighting its potential benefits in improving arm function, shoulder subluxation, walking performance, and hemiplegic shoulder pain. However, there were no significant barriers identified. Conclusion: There was a significant use of FES by physical therapists in Hyderabad to address various aspects of stroke rehabilitation. The study overall highlights its potential for improving arm function, preventing shoulder subluxation, enhancing walking, and reducing hemiplegic shoulder pain, without significant identified barriers.

Evaluation of Quantitative and Selective Sensory Fiber Dysfunction in Patients with Cirrhosis.

Chronic liver disease has been reported to be associated with peripheral neuropathy. However, which sensory fibers are affected remains unknown. The objective of this study was to examine the function of sensory nerve fibers in patients with cirrhosis using the current perception threshold (CPT) test, as well as the correlation between blood biochemical indicators related to cirrhosis and CPT values. We recruited 44 patients with liver cirrhosis and 37 healthy controls of the same age and gender. The Neurometer® system for the CPT test was used to stimulate the median nerve on the right index finger, as well as the deep and superficial peroneal nerves on the right hallux, using three distinct parameters (2000 Hz, 250 Hz, and 5 Hz). Comparative analysis was performed on the CPT values of the sensory nerves. Additionally, the correlation between CPT values and biochemical blood indicators in the study participants was analyzed. Under 2000 Hz electrical stimulation, there was a significant difference between the cirrhosis and healthy control groups in the median nerve as well as the deep and superficial peroneal nerves (p < 0.05). In addition, the median nerve CPT value of the cirrhosis group was significantly higher than that of the control group at an electrical stimulation frequency of 250 Hz (p = 0.005). There was no correlation between CPT values and blood biochemical indicators. According to the results, the sensory peripheral neuropathy in liver cirrhosis is mainly manifested as Aβ fiber neuropathy.

A reduced graphene oxide functionalized electrospun nerve wrap: Amalgamating electrical and biochemical cues to enhance nerve regeneration in median nerve injury model

Nerve injuries leads to severe impairment of target tissue and standard treatment approaches from surgery to electrical stimulation are complex, yielding only brief relief. The current study addresses such limitations with reduced graphene oxide (rGO) functionalized “Electroband”. We attempt to conjugate electrical cues in the nerve wrap with in-situ electrical stimulation in a median nerve injury model in rats, underlining the significance of combinatorial therapy for nerve regeneration. “Electroband” targets three critical aspect of nerve regeneration: neuroprotection, neuroregeneration and neuroplasticity at single stroke. The nanofibrous extracellular matrix mimicking nature of “Electroband” assisted in reconciling the injured niche by preventing anoikis, exerting neuroprotective effect as depicted with aligned growth of compressed nerve fibers. The rGO functionalization coupled with intraoperative electrical stimulation of 3 V @ 20 Hz for 10 min aided in propelling the injured nerve to denervated target, prompting fascicular growth of nerve fibers, targeting neuroplasticity. The nerve growth factor incorporation enhanced the bioactivity of scaffold, augmenting regeneration leading to exuberant growth and myelination of nascent nerve tracts. These results led to significant improvement in electrophysiological recordings with 30–32 mV CMAP value (80% recovery) in combinatorial therapy group as compared to 10–11 mV in negative controls and 13–15 mV in animals with individual therapy. We therefore, report 80% regain in muscular strength within 8 weeks of implantation with combinatorial therapy as assessed with behavioural paw gripping and scratch tape assay. Thus, we successfully demonstrated the pre-clinical efficacy of “Electroband”, reducing the time and frequency of electrical stimulation currently in clinical practice.

Effects of Electrical Stimulation on Facial Paralysis Recovery after Facial Nerve Injury: A Review on Preclinical and Clinical Studies.

Various methods have been used to improve function and manage facial nerve injury. Although electrical stimulation therapy is frequently used to treat facial paralysis, its effects have been found to vary and no clear standards have been developed. The current review describes the results of preclinical and clinical studies evaluating the effectiveness of electrical stimulation therapy in promoting the recovery of a peripheral facial nerve injury. Evidence is presented showing the efficacy of electrical stimulation in promoting nerve regeneration after peripheral nerve injuries in both animal models and human patients. The ability of electrical stimulation to promote the recovery of facial paralysis was found to depend on the type of injury (compression or transection), the species of animal tested, the type of disease, the frequency and method of electrical stimulation, and the duration of the follow-up. Electrical stimulation, however, can also have potential negative outcomes, such as reinforcing synkinesis, including mistargeted axonal regrowth via inappropriate routes; excessive collateral axonal branching at the lesion site; and multiple innervations at neuromuscular junctions. Because of the inconsistencies among studies and the low quality of evidence, electrical stimulation therapy is not currently regarded as a primary treatment of facial paralysis in patients. However, understanding the effects of electrical stimulation, as determined in preclinical and clinical studies, is important for the potential validity of future research on electrical stimulation.

Understanding the impacts of intermittent electro field on the bioelectrochemical aniline degradation system: Performance, microbial community and functional enzyme

On account of the lack of a sustainable electron donor source and the inhibitory effect of aniline on denitrogenation make it tough to achieve simultaneous removal of aniline and nitrogen. Herein, the strategy of adjusting electric field mode was applied to the electro-enhanced sequential batch reactors (E-SBRs: R1 (continuous ON), R2 (2 h-ON/2 h-OFF), R3 (12 h-ON/12 h-OFF), R4 (in the aerobic phase ON), R5 (in the anoxic phase ON)) to treat aniline wastewater. Aniline removal rate reached approximately 99% in the five systems. Decreasing electrical stimulation interval from 12 to 2 h significantly improved the electron utilization efficiency for aniline degradation and nitrogen metabolism. The total nitrogen removal was achieved from 70.31% to 75.63%. Meanwhile, the hydrogenotrophic denitrifiers of Hydrogenophaga, Thauera, and Rhodospirillales, enriched in reactors of minor electrical stimulation interval. Accordingly, the expression of functional enzyme related to electron transport was incremental with the proper electrical stimulation frequency.

Research on the Different Frequencies of Transcutaneous Electrical Acupoint Stimulation for Postpartum Pelvic Girdle Pain

Objective: To observe the clinical effect of different frequencies of transcutaneous electrical acupoint stimulation in treating postpartum pelvic girdle pain and promoting postpartum rehabilitation. Methods: From January to September 2022, 300 patients with pelvic girdle pain after spontaneous delivery in a hospital in Shaanxi Province were selected and randomly divided into three groups, low frequency, high frequency, and alternating frequency, with 100 cases in each group. In addition to routine postpartum care and psychological counseling, the three groups received transcutaneous electrical acupoint stimulation at low-frequency (2 Hz,) high-frequency (100 Hz), and alternating frequency (2/100 Hz), respectively. The differences in initial pain, pain scores before and after treatment, satisfaction with analgesic effect, and postpartum rehabilitation effect were evaluated among the three groups of patients. Results: There was a significant correlation between maternal age and postpartum pelvic girdle pain (P &lt; 0.001), but no correlation was observed between newborn birth weight and postpartum pelvic girdle pain (P &gt; 0.05). After 1d/2d of treatment, the pain scores and rehabilitation effect of patients in the alternating-frequency group and low-frequency group were significantly better than those in the high-frequency group, and the postpartum curative effect of patients in the alternating-frequency group was the best, followed by the low-frequency group, and the high-frequency group; the differences were statistically significant (P &lt; 0.001). Among the three groups, the alternating-frequency group had the highest satisfaction with the analgesic effect and the highest rate of selecting the same analgesic regimen the next time; the differences were statistically significant (P &lt; 0.001). Conclusion: Transcutaneous electrical acupoint stimulation at different frequencies is safe and effective in treating postpartum pelvic girdle pain and beneficial to postpartum rehabilitation. Sparse-dense wave stimulation is effective in treating postpartum pelvic girdle pain. It has the best effect in promoting postpartum rehabilitation and the highest patient satisfaction. Therefore, its application in clinical practice is highly recommended.

Sophoridine manifests as a leading compound for anti-arrhythmia with multiple ion-channel blocking effects

BackgroundSophoridine (SR) has shown the potential to be an antiarrhythmic agent. However, SR's electrophysiological properties and druggability research are relatively inadequate, which limits the development of SR as an antiarrhythmic candidate. PurposeTo facilitate the development process of SR as an antiarrhythmic candidate, we performed integrated studies on the electrophysiological properties of SR in vitro and ex vivo to gain more comprehensive insights into the multi-ion channel blocking effects of SR, which provided the foundation for the further drugability studies in antiarrhythmic and safety studies. Firstly, SR's electrophysiological properties and antiarrhythmic potentials were recorded and assessed at the cell and tissue levels by comprehensively integrating the patch clamp with the Electrical and Optical Mapping systems. Subsequently, the antiarrhythmic effects of SR were validated by aconitine and ouabain-induced arrhythmia in vivo. Finally, the safety of SR as an antiarrhythmic candidate compound was evaluated based on the guidelines of the Comprehensive in Vitro Proarrhythmia Assay (CiPA). Study designThe antiarrhythmic effect of SR was evaluated at the in vitro, ex vivo, and in vivo levels. MethodsIsolated primary cardiomyocytes and stable cell lines were prepared to explore the electrophysiologic properties of being a multiple ion-channel blocker in vitro by whole-cell patch clamp. Using electrical and optical mapping, the negative chronotropic effect of SR was determined in langendorff-perfused rat or guinea-pig hearts.The antiarrhythmic activity of SR was assessed by the ex vivo tachyarrhythmia models induced by left coronary artery ligation (LCAL) and isoproterenol (ISO). Canonical models of aconitine and ouabain-induced arrhythmia were used to verify the antiarrhythmic effects in vivo. Finally, the pro-arrhythmic risk of SR was detected in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes (hSCCMs) using a Microelectrode array (MEA). ResultsSingle-cell patch assay validated the multiple ion-channel blockers of SR in transient outward current potassium currents (Ito), l-type calcium currents (ICa-l), and rapid activation delayed rectifier potassium currents (IKr). SR ex vivo depressed heart rates (HR) and ventricular conduction velocity (CV) and prolonged Q-T intervals in a concentration-dependent manner. Consistent with the changes in HRs, SR extended the active time of hearts and increased the action potential duration measured at 90% repolarization (APD90). SR could also significantly lengthen the onset time and curtail the duration of spontaneous ventricular tachycardia (VT) in the ex vivo arrhythmic model induced by LCAL. Meanwhile, SR could also significantly upregulate the programmed electrical stimulation (PES) frequency after the ISO challenge in forming electrical alternans and re-entrant excitation. Furthermore, SR exerted antiarrhythmic effects in the tachyarrhythmia models induced by aconitine and ouabain in vivo. Notably, the pro-arrhythmic risk of SR was shallow for a moderate inhibition of the human ether-à-go-go-related gene (hERG) channel. Moreover, SR prolonged field potential duration (FPDc) of hSCCMs in a concentration-dependent manner without early after depolarization (EAD) and arrhythmia occurrence. ConclusionOur results indicated that SR manifested as a multiple ion-channel blocker in the electrophysiological properties and exerts antiarrhythmic effects ex vivo and in vivo. Meanwhile, due to the low pro-arrhythmic risk in the hERG inhibition assay and the induction of EAD, SR has great potential as a leading candidate in the treatment of ventricular tachyarrhythmia.

A Real-Time Non-Implantation Bi-Directional Brain-Computer Interface Solution without Stimulation Artifacts.

The non-implantation bi-directional brain-computer interface (BCI) is a neural interface technology that enables direct two-way communication between the brain and the external world by both "reading" neural signals and "writing" stimulation patterns to the brain. This technology has vast potential applications, such as improving the quality of life for individuals with neurological and mental illnesses and even expanding the boundaries of human capabilities. Nonetheless, non-implantation bi-directional BCIs face challenges in generating real-time feedback and achieving compatibility between stimulation and recording. These issues arise due to the considerable overlap between electrical stimulation frequencies and electrophysiological recording frequencies, as well as the impediment caused by the skull to the interaction of external and internal currents. To address those challenges, this work proposes a novel solution that combines the temporal interference stimulation paradigm and minimally invasive skull modification. A longitudinal animal experiment has preliminarily validated the feasibility of the proposed method. In signal recording experiments, the average impedance of our scheme decreased by 4.59 kΩ, about 67%, compared to the conventional technique at 18 points. The peak-to-peak value of the Somatosensory Evoked Potential increased by 8%. Meanwhile, the signal-to-noise ratio of Steady-State Visual Evoked Potential increased by 5.13 dB, and its classification accuracy increased by 44%. The maximum bandwidth of the resting state rose by 63%. In electrical stimulation experiments, the signal-to-noise ratio of the low-frequency response evoked by our scheme rose by 8.04 dB, and no stimulation artifacts were generated. The experimental results show that signal quality in acquisition has significantly improved, and frequency-band isolation eliminates stimulation artifacts at the source. The acquisition and stimulation pathways are real-time compatible in this non-implantation bi-directional BCI solution, which can provide technical support and theoretical guidance for creating closed-loop adaptive systems coupled with particular application scenarios in the future.

Transcranial Direct Current Stimulation Combined with Peripheral Neuromuscular Stimulation Improves Quality of Life, Fatigue, and Pain in a Patient with Rheumatoid Arthritis and Refractory Radicular Pain Related to Spinal Stenosis

Background: Transcranial direct current stimulation (tDCS) has emerged as an adjuvant noninvasive neuromodulation tool to control fatigue and pain. To date, no studies have assessed the safety and efficiency of tDCS in patients with rheumatoid arthritis and with fatigue, poor quality of life, and refractory radicular pain associated with spinal stenosis. Case Presentation: An 85-year-old woman patient presented with rheumatoid arthritis in remission, refractory radicular pain-associated spinal stenosis, fatigue, and impaired quality of life. The patient underwent 16 daily sessions of tDCS intervention (2 mA, 20 min, positively and negatively charged electrodes were positioned at C1 and Fp2, respectively), in addition to simultaneous peripheral neuromuscular electrical stimulation (frequency of 100 Hz and amplitude of 500 μs). After the intervention, neither disease relapse nor clinical intercurrence occurred. Moreover, there was a significant and sustained improvement in her health-related quality of life, with a reduction in the level of pain and chronic fatigue. Conclusion: The present case report shows that tDCS is safe and may be an adjuvant tool for the treatment of pain and fatigue in patients with systemic autoimmune disease, as well as for improving quality of life. Further studies are required to corroborate this case report.

Blood Flow Restricted Electrical Stimulations to Prevent or Attenuate Symptoms of Muscle Damage

ABSTRACT The objective of this study was to determine if performing electrical stimulations (E-STIM) under blood flow restriction (BFR) would result in a greater protective effect against symptoms of muscle damage. 18 individuals (9 females) completed a damaging bout of exercise followed by a low frequency E-STIM treatment protocol on both arms, one of which was completed under BFR. The treatment protocol was then repeated 24-hours post-exercise. There were main effects of time for muscle thickness (pre: 3.5 cm; 48 h post: 3.8 cm; BF10 = 88.476), discomfort (pre: 0.0 au; 48 h post: 4.2 au; BF10 = 241.996), and isometric strength (pre: 278 N; 48 h post: 232 N; BF10 = 10,289.894) which all changed as a result of the damaging exercise protocol, but there were no differences between conditions [all Bayes Factors (BF10) < 0.28]. The effectiveness of low frequency E-STIM for preventing the onset of exercise-induced muscle damage would not appear to be enhanced if performed under BFR.

Torque and Discomfort During Electrically Evoked Muscle Contractions in Healthy Young Adults: Influence of Stimulation Current and Pulse Frequency

ObjectiveTo investigate (1) how current and pulse frequency of electrical stimulation (ES) as well as contraction mode (isometric, concentric, and eccentric) influence torque output and discomfort and (2) how familiarization by repeated ES sessions influences ratings of perceived discomfort. DesignAn experimental study, 3 sessions. SettingA university laboratory. ParticipantsEight healthy participants (5 men, 3 women; mean age 25.2 years; N=8). InterventionsParticipants completed 3 trial days, each including 17 electrically evoked thigh muscle contractions. On each trial day, the first 6 contractions consisted of 2 isometric, 2 concentric, and 2 eccentric muscle contractions randomly ordered with a fixed stimulation current and pulse frequency (200 mA, 20 Hz), while the remaining 11 muscle contractions were all isometric with randomly ordered combinations of current (100-250 mA) and pulse frequency (20-100 Hz). Main Outcome MeasuresTorque and perceived discomfort were measured for each ES-evoked contraction. ResultsOverall, the findings revealed that a higher stimulation frequency was associated with an increased torque without increased discomfort, while higher currents were associated with increases of both torque and discomfort. Contraction type did not influence level of discomfort, despite eccentric contractions eliciting higher torque compared with concentric and isometric contractions (P<.001). Finally, a significant familiarization to ES (P<.001) was observed after just 1 of 3 identical stimulation sessions. ConclusionsThe outlined data suggest that to elicit high torque levels while minimizing levels of discomfort in young subjects, eccentric muscle contractions evoked with a low stimulation current, and a high pulse frequency are preferable. Furthermore, a single familiarization session significantly lowers rating of perceived discomfort during ES.

Inferring stimulation induced short-term synaptic plasticity dynamics using novel dual optimization algorithm.

Experimental evidence in both human and animal studies demonstrated that deep brain stimulation (DBS) can induce short-term synaptic plasticity (STP) in the stimulated nucleus. Given that DBS-induced STP may be connected to the therapeutic effects of DBS, we sought to develop a computational predictive model that infers the dynamics of STP in response to DBS at different frequencies. Existing methods for estimating STP-either model-based or model-free approaches-require access to pre-synaptic spiking activity. However, in the context of DBS, extracellular stimulation (e.g. DBS) can be used to elicit presynaptic activations directly. We present a model-based approach that integrates multiple individual frequencies of DBS-like electrical stimulation as pre-synaptic spikes and infers parameters of the Tsodyks-Markram (TM) model from post-synaptic currents of the stimulated nucleus. By distinguishing between the steady-state and transient responses of the TM model, we develop a novel dual optimization algorithm that infers the model parameters in two steps. First, the TM model parameters are calculated by integrating multiple frequencies of stimulation to estimate the steady state response of post-synaptic current through a closed-form analytical solution. The results of this step are utilized as the initial values for the second step in which a non-derivative optimization algorithm is used to track the transient response of the post-synaptic potential across different individual frequencies of stimulation. Moreover, in order to confirm the applicability of the method, we applied our algorithm-as a proof of concept-to empirical data recorded from acute rodent brain slices of the subthalamic nucleus (STN) during DBS-like stimulation to infer dynamics of STP for inhibitory synaptic inputs.

Acute Effects of Whole-Body Electromyostimulation on Energy Expenditure at Resting and during Uphill Walking in Healthy Young Men.

The effects of the different electrical frequencies of whole-body electrical stimulation (WB-EMS) on energy expenditure (EE) and the respiratory exchange ratio (RER) remain poorly understood. This study aimed to determine the effects of different WB-EMS electrical frequencies on EE and the RER during supine resting and uphill walking. A total of 10 healthy and recreationally active men (21.6 ± 3.3 years old) participated in the present study. Participants completed two testing sessions in a randomized order. In each session, a variety of impulse frequencies (1 hertz (Hz), 2 Hz, 4 Hz, 6 Hz, 8 Hz, and 10 Hz) were applied in a randomized order, allowing a 10 min passive recovery between them. Oxygen consumption and carbon dioxide production were measured to calculate EE and the RER. All frequencies increased EE at rest (all p ≤ 0.001), with 4 Hz being the frequency producing the highest increase (Δ = 8.89 ± 1.49 kcal/min), as did 6 Hz (Δ = 8.05 ± 1.52 kcal/min) and 8 Hz (Δ = 7.04 ± 2.16 kcal/min). An increment in the RER at rest was observed with 4 Hz, 6 Hz, 8 Hz and 10 Hz (all p ≤ 0.016), but not with 1 Hz and 2 Hz (p ≥ 0.923). During uphill walking, the frequency that elicited the highest increase in EE was 6 Hz (Δ = 4.87 ± 0.84 kcal/min) compared to the unstimulated condition. None of the impulse frequencies altered the RER during uphill walking. WB-EMS increases EE in healthy young men both during resting and uphill walking.

Selective neuromodulation of retinal ganglion cells via a hybrid optic-nerve and retinal neuroprosthesis for visual restoration.

A visual neuroprosthesis delivers electrical stimulation to the surviving neural cells of the visual pathway to produce prosthetic vision. While the retina is often chosen as the stimulation site, current retinal prostheses are hindered by the lack of functional selectivity that impairs the resolution. A possible strategy to improve the resolution is to combine the retinal stimulation and the stimulation of the optic nerve bundle, which contains myelinated fibres of retinal ganglion cells (RGCs) axons that vary in diameter. In this study, we used a computational model of retinal ganglion cells (RGCs) with myelinated axons to predict whether the frequency of electrical stimulation delivered to the optic nerve can be modulated to preferentially inhibit a subset of optic nerve fibres classified by diameter. The model combined a finite element model of bipolar penetrating electrodes delivering sinusoidal stimulation in the range of 25-10000 Hz to the optic nerve, and a double-cable model, to represent an optic nerve fibre. We found that the diameter of the axon fibre and ion kinetic properties of the RGC affect the neuron's frequency response, demonstrating the potential of an optic nerve stimulation to produce selective inhibition based on the axon fibre size. Clinical Relevance-This establishes the importance of considering the size of the nerve cell axons, as well as the functional type of the RGC, in stimulating the optic nerve. This can be exploited to facilitate functionally selective neuromodulation when used in conjunction with retinal stimulation.

High-throughput rhythmic regulation of cardiomyocytes by integrated electrical stimulation and video-based automated analysis biosensing platform

In cardiac tissue engineering, electric stimulation is an efficient approach to improve the formation of cardiac tissue from individual cardiomyocyte. The regulation conditions of electric stimulation should be screened in an efficient way. However, the lack of high-throughput and large-scale assessment platforms limited the effectively screen the regulation conditions. Here, we develop a high-throughput integrated electrical stimulation system to rhythmically regulate the cardiomyocytes in situ. The state of regulated cardiomyocytes is characterized by a video-based automated biosensing system to analyze the beating of cardiomyocytes. Electrical stimulation conditions are optimized to regulate the cardiomyocyte state in vitro to replace the complex bioactive molecules and materials. By the video analysis, the accurate beating rate and regularity of cardiomyocyte can be determined. The results show that electrical stimulation frequency is a significant factor to regulate the cardiomyocyte beating. The electrical stimulation with a frequency of 3 Hz can effectively regulate the primary rat cardiomyocytes with normal rhythm. This high-throughput electrical stimulation and a video-based automated biosensing system will be a promising and powerful tool to effectively optimize the regulation conditions of cardiomyocyte in vitro, and possess broad application prospects in cardiac tissue engineering and pharmaceutical industry.

A Multi-Component Physiotherapeutic Intervention among Schoolchildren with Myopia: 3D-Based Vision Training Program with Auditory Frequency Entrainment and Electrical Stimulation

Purpose. This study evaluated whether 3D-based vision training (VT) with visual cortex-activated auditory frequency entrainment and bilateral orbital electrical stimulation (ES) could prevent the progression of myopia among schoolchildren. Methods. In this two-stage, randomized, crossover, single-blind study, pre- and post-logMAR visual acuity and refractive error from 27 schoolchildren with myopia (≤−0.50 D) were evaluated among four groups: (1) sham control with no VT, frequency following response (FFR), or ES (control group); (2) 3D-based VT only (VT group); (3) VT with FFR generated through visual cortex-activated auditory entrainment (VT-FFR group); and (4) VT with FFR and bilateral orbital ES (VT-FFR-ES group). In stage 1, the intervention was administered for 30 min to all groups using a randomized crossover design. In stage 2, the intervention was administered for 30 min/day, 3 days a week, for 4 weeks to evaluate the effectiveness of intervention. Results. Compared with the pre-test, post-test logMAR visual acuity after a single intervention was not significantly different in control and VT groups, but significantly improved in the VT-FFR (−0.08 ± 0.11) and VT-FFR-ES groups (−0.13 ± 0.14). Compared with the pre-test, post-test refractive error by spherical equivalent in VT-FFR-ES group for the 4-week intervention was significantly (&lt;0.001) improved (0.21 D) compared with the control group (−0.1 D). Conclusions. The multicomponent physiotherapeutic intervention of 3D-based VT with auditory FFR and bilateral orbital ES can inhibit the progression of myopia. This intervention can be used as a noninvasive physiotherapeutic approach to prevent or reduce the severity of myopia.

Feedback Altitude Control of a Flying Insect–Computer Hybrid Robot

Unlike biomimetic methods, the insect–computer hybrid is an alternative approach to developing insect-scale robots. Insect–computer hybrid is a technique that transforms a living insect into a controllable robot by embedding it with artificial devices. In this article, a beetle ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Mecynorrhina torquata</i> ) was transformed into a hybrid flying system by mounting an electronic backpack and implanting electrodes on it. Wing trajectories during fictive flight climbing and flight diving were captured to investigate the natural flight-height control of beetles. Compare with the electrically induced wing trajectories via basalar, subalar, and third axillary (3Ax) muscle stimulations, we hypothesized that the basalar muscles are involved in ascending flight, whereas the 3Ax muscles function to reduce the flight-height. By reproducing the electrical stimulations on bilateral muscle pairs during free flights, we found that stimulations of the basalar muscle pair increased vertical accelerations. In contrast, the 3Ax muscle pair's stimulation decreased vertical accelerations gradually as a function of the electrical stimulation frequency. Accordingly, a proportional-derivative feedback controller was proposed to maintain the beetles' flight-height using frequency-dependent electrical pulses on the basalar and 3Ax muscles. In this article, the altitude control of a free-flying beetle was demonstrated for the first time.

Research on feature classification of lower limb motion imagination based on electrical stimulation to enhance rehabilitation

Motor imaging therapy is of great significance to the rehabilitation of patients with stroke or motor dysfunction, but there are few studies on lower limb motor imagination. When electrical stimulation is applied to the posterior tibial nerve of the ankle, the steady-state somatosensory evoked potentials (SSSEP) can be induced at the electrical stimulation frequency. In order to better realize the classification of lower extremity motor imagination, improve the classification effect, and enrich the instruction set of lower extremity motor imagination, this paper designs two experimental paradigms: Motor imaging (MI) paradigm and Hybrid paradigm. The Hybrid paradigm contains electrical stimulation assistance. Ten healthy college students were recruited to complete the unilateral movement imagination task of left and right foot in two paradigms. Through time-frequency analysis and classification accuracy analysis, it is found that compared with MI paradigm, Hybrid paradigm could get obvious SSSEP and ERD features. The average classification accuracy of subjects in the Hybrid paradigm was 78.61%, which was obviously higher than the MI paradigm. It proves that electrical stimulation has a positive role in promoting the classification training of lower limb motor imagination.

Influence of wide-pulse neuromuscular electrical stimulation frequency and superimposed tendon vibration on occurrence and magnitude of extra torque

Low-frequency and high-frequency wide-pulse neuromuscular electrical stimulation (NMES) can generate extra-torque (ET) via afferent pathways. Superimposing tendon vibration (TV) to NMES can increase the activation of these afferent pathways and favour ET generation. Knowledge of the characteristics of ET is essential to implement these stimulation paradigms in clinical practice. Thus, we aimed at investigating the effects of frequency and TV superimposition on the occurrence and magnitude of ET in response to wide-pulse NMES. NMES-induced isometric plantar flexion torque was recorded in 30 healthy individuals who performed five NMES protocols: wide-pulse low-frequency (1 ms; 20 Hz; WPLF) and wide-pulse high-frequency (1 ms; 100 Hz; WPHF) without and with superimposed TV (1 mm; 100 Hz) and conventional NMES (50 µs; 20 Hz; reference protocol). Each NMES protocol began with an adjustment of NMES intensity in order to reach 10% of maximal voluntary contraction then consisted of three 20-s trains interspersed by 90 s of rest. The ET occurrence was similar for WPLF and WPHF (p=0.822). In the responders, the ET magnitude was greater for WPHF than WPLF (p<0.001). There was no effect of superimposed TV on ET characteristics. This study reported an effect of NMES frequency on ET magnitude, whereas TV superimposition did not affect this parameter. In the context of our experimental design decisions, the present findings question the clinical use of wide-pulse NMES and its combination with superimposed TV. Yet, further research is needed in order to maximize force production through the occurrence and magnitude of ET.