Influence of Graphene-Based Nanocomposites in Neurogenesis and Neuritogenesis: A Brief Summary

Graphene is a prospective candidate for various biomedical applications, including drug transporters, bioimaging agents, and scaffolds for tissue engineering, thanks to its superior electrical conductivity and biocompatibility. The clinical issue of nerve regeneration and rehabilitation still has a major influence on people's lives. Nanomaterials based on graphene have been exploited extensively to promote nerve cell differentiation and proliferation. Their high electrical conductivity and mechanical robustness make them appropriate for nerve tissue engineering. Combining graphene with other substances, such as biopolymers, may transmit biochemical signals that support brain cell division, proliferation, and regeneration. The utilization of nanocomposites based on graphene in neurogenesis and neuritogenesis is the primary emphasis of this review. Here are some examples of the many synthetic strategies used. For neuritogenesis and neurogenesis, it has also been explored to combine electrical stimulation with graphene-based materials.

The role of transcranial direct current stimulation in diminishing the risk of pneumonia in patients with dysphagia: A double-blinded randomized clinical trial

Background: Dysphagia can be a life-threatening issue for post-stroke patients, with aspiration pneumonia (AP) being a common risk. However, there is hope through the potential combination of transcranial direct current stimulation (tDCS) and classical behavior therapy. Our study aims to investigate the effectiveness of this combination in diminishing the risk of AP in patients with dysphagia who suffered from stroke. Methods: In this randomized, parallel-group, blinded clinical trial, 48 patients were allocated into the sham group (speech therapy + 30 seconds of tDCS) and the real group (speech therapy + 20 minutes of tDCS). We used the Mann Assessment of Swallowing Ability (MASA) as an assessment tool. We assessed patients at baseline, one day after treatment, and at a one-month follow-up. Results: Groups showed no significant difference at baseline. After treatment, the real group showed a significant difference in the severity risk of AP (P = 0.02); the same was for the follow-up (P = 0.04). The number of patients showing severe risk of AP was higher in the sham group after treatment (n = 13, 54.20%) and at follow-up (n = 4, 18.20%) than the real group (n = 4, 16.70%; n = 1, 4.50%, respectively). None of the patients reported the history of AP at any stage of assessment. Conclusion: Although the results were more promising in the real group than the sham group in reducing the risk of AP, both techniques can prevent AP. Therefore, we recommend early dysphagia management to prevent AP regardless of the treatment protocol.

Transvenous stimulation yields exposure-dependent protection from ventilator-induced diaphragm atrophy

INTRODUCTION

Mechanical ventilation (MV) induced diaphragmatic atrophy can contribute to weaning difficulties. A temporary transvenous diaphragm neurostimulation (TTDN) device that elicits diaphragm contractions has previously been shown to mitigate atrophy during MV in a preclinical model; however, its effects on different myofiber types remain unknown. It is important to examine these effects, as each myofiber type plays a role in the range of diaphragmatic movements to ensure successful liberation from MV.

METHODS

Eighteen pigs were assigned to one of three ventilation conditions for 50 hours: MV-Only, and TTDN contracting the diaphragm every other breath or every breath synchronously with MV (TTDN50%+MV and TTDN100%+MV, respectively). Six pigs were assigned to a never-ventilated, never-paced (NV-NP) group. Diaphragm biopsies were fiber-typed and myofiber cross-sectional areas were measured and normalized to subject weight.

RESULTS

There were effect differences based on TTDN exposure. The TTDN100%+MV group showed less atrophy in Type 2A and 2X myofibers than the TTDN50%+MV group, relative to the NV-NP group. The TTDN50%+MV animals showed less MV-induced atrophy in Type 1 myofibers than TTDN100%+MV animals. Additionally, there were no significant differences in proportions of myofiber types between each condition.

CONCLUSION

TTDN applied synchronously with MV for 50 hours mitigates MV-induced atrophy in all myofiber types, with no evidence of stimulation-induced myofiber-type shift. At this stimulation profile, enhanced protection for Type 1 myofibers and Type 2 myofibers was seen when diaphragm contractions occurred every other breath and every breath, respectively.

Multiparametric non-linear TENS modulation to integrate intuitive sensory feedback

OBJECTIVE

Transcutaneous Electrical Nerve Stimulation (TENS) has been recently introduced in neurorehabilitation and neuroprosthetics as a promising, non-invasive sensory feedback restoration alternative to implantable neurostimulation. Yet, the adopted stimulation paradigms are typically based on single-parameter modulations (e.g., pulse amplitude PA, pulse-width PW or pulse frequency PF). They elicit artificial sensations characterized by a low intensity resolution (e.g., few perceived levels), low naturalness and intuitiveness, hindering the acceptance of this technology. To address these issues, we designed novel multiparametric stimulation paradigms, featuring the simultaneous modulation of multiple parameters, and implemented them in real-time tests of performance when exploited as artificial sensory inputs. 
Approach. We initially investigated the contribution of PW and PF variations to the perceived sensation magnitude through discrimination tests. Then, we designed three multiparametric stimulation paradigms comparing them with a standard PW linear modulation in terms of evoked sensation naturalness and intensity. The most performant paradigms were then implemented in real-time in a Virtual Reality - TENS platform to assess their ability to provide intuitive somatosensory feedback in a functional task. 
Main results. Our study highlighted a strong negative correlation between perceived naturalness and intensity: less intense sensations are usually deemed as more like natural touch. In addition, we observed that PF and PW changes have a different weight on the perceived sensation intensity. As a result, we adapted the Activation Charge Rate (ACR) equation, proposed for implantable neurostimulation to predict the perceived intensity while co-modulating the PF and charge per pulse, to TENS (ACRT). ACRT allowed to design different multiparametric TENS paradigms with the same absolute perceived intensity. Although not reported as more natural, the multiparametric paradigm, based on sinusoidal PF modulation, resulted being more intuitive and subconsciously integrated than the standard linear one. This allowed subjects to achieve a faster and more accurate functional performance. 
Significance. Our findings suggest that TENS-based, multiparametric neurostimulation, despite not consciously perceived naturally, can provide integrated and more intuitive somatosensory information, as functionally proved. This could be exploited to design novel encoding strategies able to improve the performance of non-invasive sensory feedback technologies.

Energy efficiency of pulse shaping in electrical stimulation: the interdependence of biophysical effects and circuit design losses

Power efficiency in electrical stimulator circuits is crucial for developing large-scale multichannel applications like bidirectional brain-computer interfaces and neuroprosthetic devices. Many state-of-the-art papers have suggested that some non-rectangular pulse shapes are more energy-efficient for exciting neural excitation than the conventional rectangular shape. However, additional losses in the stimulator circuit, which arise from employing such pulses, were not considered. In this work, we analyze the total energy efficiency of a stimulation system featuring non-rectangular stimuli, taking into account the losses in the stimulator circuit. To this end, activation current thresholds for different pulse shapes and durations in cortical neurons are modeled, and the energy required to generate the pulses from a constant voltage supply is calculated. The proposed calculation reveals an energy increase of 14-51% for non-rectangular pulses compared to the conventional rectangular stimuli, instead of the decrease claimed in previous literature. This result indicates that a rectangular stimulation pulse is more power-efficient than the tested alternative shapes in large-scale multichannel electrical stimulation systems.

Effects of NMES-elicited versus voluntary low-level conditioning contractions on explosive knee extensions

OBJECTIVES

Electrically-induced or voluntary conditioning-contractions (CC) can be used to affect contractile properties of a subsequent explosive contraction (EC). Here, we aimed at comparing the effect of neuromuscular-electrical-stimulation (NMES) vs voluntary CC performed prior to explosive contractions of the knee extensors.

METHODS

A 10 sec NMES CC (100Hz, 1000μs, 10% MVC), or a voluntary contraction (VOL CC) mimicking the NMES CC, preceded an isometric EC of the knee extensors. Explosive contraction was performed with the goal to reach the target (70% MVC) as quickly as possible.

RESULTS

All the parameters related with the explosive contractions' muscle-output were similar between protocols (difference ranging from 0.23%, Mean Torque; to 5.8%, Time to Target), except for the Time to Peak Torque, which was lower when preceded by NMES (11.1%, p=0.019). Interestingly, the RTD 0-50 ms_EC was 37.3% higher after the NMES compared with the VOL CC protocol.

CONCLUSION

Explosive contraction was potentiated by an NMES CC as compared with a voluntary CC. This may be due to a reduction in descending drive following VOL CC, which has been shown to occur even with low-level voluntary efforts. These findings could be used to improve rehabilitation or training protocols that include conditioning contractions.

Osteoporosis after spinal cord injury: aetiology, effects and therapeutic approaches

Osteoporosis is a long-term consequence of spinal cord injury (SCI) that leads to a high risk of fragility fractures. The fracture rate in people with SCI is twice that of the general population. At least 50% of these fractures are associated with clinical complications such as infections. This review article presents key features of osteoporosis after SCI, starting with its aetiology, a description of temporal and spatial changes in the long bones and the subsequent fragility fractures. It then describes the physical and pharmacological approaches that have been used to attenuate the bone loss. Bone loss after SCI has been found to be highly site-specific and characterised by large inter-variability and site-specific changes. The assessment of the available interventions is limited by the quality of the studies and the lack of information on their effect on fractures, but this evaluation suggests that current approaches do not appear to be effective. More studies are required to identify factors influencing rate and magnitude of bone loss following SCI. In addition, it is important to test these interventions at the sites that are most prone to fracture, using detailed imaging techniques, and to associate bone changes with fracture risk. In summary, bone loss following SCI presents a substantial clinical problem. Identification of at-risk individuals and development of more effective interventions are urgently required to reduce this burden.

The Effect of Transcutaneous Electric Nerve Stimulation (TENS) on Anxiety and Fear in Children Aged 9-14 Years

Introduction

Dental fear or dental phobia is caused by previous unpleasant dental experiences and pain. It can result in delaying or avoiding dental visits. Most often it leads to individuals avoiding visiting the dentist until physical pain completely impairs the quality of life.

Objectives

Transcutaneous electrical nerve stimulation (TENS) is a method of pain relief involving the use of a mild electrical current. The main aim of this study was to examine whether the TENS device affects the reduction of anxiety and fear during dental procedures.

Material and Methods

The study was conducted on a sample of 125 respondents, aged 9-14 years. Statistical significance of differences between pre- and post-treatment results on all applied measuring instruments was verified by the t-test for dependent samples. The calculation was performed for all respondents and individually for the three observed groups. The Children`s Fear Survey Schedule – Dental Subscale test was used to assess anxiety and fear.

Results

The results on the CFSS-DS scale in all subjects did not differ statistically significantly before and after treatment (p > 0.05). The results on the CFSS-DS scale in subjects who received TENS were statistically significantly different before and after treatment (p < 0.01). The results on the CFSS-DS scale in subjects who received local anesthesia were statistically significantly different before and after treatment (p < 0.05).

Conclusion

The TENS device had an anxiolytic effect after the first visit.

Optogenetic Stimulation of Basal Forebrain Parvalbumin Neurons Activates the Default Mode Network and Associated Behaviors

Activation of the basal forebrain (BF) has been associated with increased attention, arousal, and a heightened cortical representation of the external world. In addition, BF has been implicated in the regulation of the default mode network (DMN) and associated behaviors. Here, we provide causal evidence for a role of BF in DMN regulation, highlighting a prominent role of parvalbumin (PV) GABAergic neurons. The optogenetic activation of BF PV neurons reliably drives animals toward DMN-like behaviors, with no effect on memory encoding. In contrast, BF electrical stimulation enhances memory performance and increases DMN-like behaviors. BF stimulation has a correlated impact on peptide regulation in the BF and ACC, enhancing peptides linked to grooming behavior and memory functions, supporting a crucial role of the BF in DMN regulation. We suggest that in addition to enhancing attentional functions, the BF harbors a network encompassing PV GABAergic neurons that promotes self-directed behaviors associated with the DMN.

A Mixed Methods Exploration of Electrical Stimulation in Veterans with Fibromyalgia Symptoms & Affective Disorders

INTRODUCTION

Past research has shown that electrical stimulation has modest beneficial effects on symptoms of fibromyalgia, which is also commonly associated with anxiety and depression. The purpose of the current study was to evaluate the effectiveness and utilization of electrical stimulation (AID or M units) at-home by Veterans.

METHODS

Sixty Veterans were identified using the Fibromyalgia Symptoms Questionnaire for an electrical stimulation trial during January 1-December 31, 2016 at a Midwestern VA Medical Center. Each patient completed a brief, semi-structured phone interview, which included an inquiry about the benefits of the units on affective symptoms.

RESULTS

Quantitative findings suggest that participants who were given any kind of unit (AID or M units) did not have a significant change in pain level from baseline to follow-up. Participants who were given any kind of unit (AID or M units) did not report a significant change in anxiety, depressive, or insomnia symptoms from baseline to follow-up. Qualitative findings produced three thematic maps: utilization, effectiveness, and satisfaction.

LIMITATIONS

This study used a quasi-experimental, one group, pre-/post-test design, and explored the benefits of programming when based on patient self-selection. The instruments used in this study were self-report measures, and the lack of change may have been due to the use of binary versus continuous measures. The findings may differ among other Veterans as the current sample had a larger representation of minority groups compared to the typical Veteran profile.

CONCLUSIONS

This information is invaluable in helping patients who suffer from fibromyalgia symptoms and affective disorders and for the providers aiding in their treatment.

Electromyographic Evaluation of the Pelvic Muscles Activity After High-Intensity Focused Electromagnetic Procedure and Electrical Stimulation in Women With Pelvic Floor Dysfunction

Introduction

Impaired coordination, relaxation, and atrophy of pelvic floor muscles (PFMs) may cause various health issues referred to as pelvic floor dysfunction (PFD). In recent years, electromagnetic noninvasive stimulation of the pelvic floor was successfully used to treat PFD symptoms.

Aim

This study aims to compare the effectiveness of electrical and magnetic noninvasive stimulation for the treatment of PFD in postpartum women.

Methods

2 intervention groups treated with high-intensity focused electromagnetic ([HIFEM]; G1) procedure and electrical stimulation (G2) were established along with the control group (G3). Patients received 10 therapies delivered at the hospital (G1; 2–3 times per week) or self-administered at home (G2; every other day) after initial training. The protocol was identical for both modalities. Functionality of the PFM was examined by surface electromyography measurements (maximal voluntary contraction [MVC]; mean MVC; muscle activity at rest; endurance of contraction) while patient's subjective perception of pelvic floor functionality was assessed by Pelvic Floor Impact Questionnaire–Short Form 7 (PFIQ-7) standardized questionnaire. Changes in electromyography values and PFIQ-7 scores were statistically evaluated from baseline to after all treatments.

Main Outcome Measure

The main outcome measure was enhancement of PFM activity.

Results

In total, 95 patients (G1 = 50; G2 = 25; G3 = 20) participated in the study. The MVC, mean MVC, and endurance were lowered in symptomatic patients. After the treatments, these parameters significantly increased (P < .001) and moved toward the values of healthy population. Electrogenesis at relaxation revealed divergent tendencies in the G1 and G2 groups. PFIQ-7 scores significantly improved in treated patients (P < .001). In general, superior results were documented in the HIFEM group as it reached improvement of electromyography parameters from 48% to 59% (electrical stimulation from 7% to 36%) and similarly the improvement of PFIQ-7 score by 57% (electrical stimulation by 32%).

Conclusion

This study documented that the HIFEM procedure was significantly more effective than electrical stimulation in treatment of PFD in postpartum women. Both the objective and subjective evaluation indicates more profound effects of magnetic stimulation.

Elena S, Dragana Z, Ramina S, et al. Electromyographic Evaluation of the Pelvic Muscles Activity After High-Intensity Focused Electromagnetic Procedure and Electrical Stimulation in Women With Pelvic Floor Dysfunction. Sex Med 2020;8:282–289.

MUSCLE MITOCHONDRIAL CAPACITY AND ENDURANCE IN ADULTS WITH TYPE 1 DIABETES

The impact of type 1 diabetes (T1D) on muscle endurance and oxidative capacity is currently unknown.

Purpose

Measure muscle endurance and oxidative capacity of adults with T1D compared to controls.

Methods

A cross-sectional study design with a control group was used. Subjects (19-37 years old) with T1D (n=17) and controls (n=17) were assessed with hemoglobin A1c (HbA1c) and casual glucose. Muscle endurance was measured with an accelerometer at stimulation frequencies of 2, 4, and 6 Hz for a total of nine minutes. Mitochondrial capacity was measured using near-infrared spectroscopy after exercise as the rate constant of the rate of recovery of oxygen consumption.

Results

T1D and control groups were similar in age, sex, height, and race. The T1D group had slightly higher BMI values and adipose tissue thickness over the forearm muscles. Casual glucose was 150±70 mg/dL for T1D and 98±16 mg/dL for controls (P=0.006). HbA1c of T1D subjects was 7.1±0.9% and 5.0±0.4% for controls (P<0.01). Endurance indexes at 2, 4, and 6 Hz were 94.5±5.2%, 81.8±8.4%, and 68.6±13.5% for T1D and 94.6±4.1%, 85.9±6.3%, and 68.7±15.4% for controls (p = 0.97, 0.12, 0.99, respectively). There were no differences between groups in mitochondrial capacity (T1D= 1.9±0.5 min^-1 and control=1.8±0.4 min^-1, P=0.29) or reperfusion rate (T1D= 8.8±2.8s and control=10.3±3.0s, P=0.88). There were no significant correlations between HbA1c and either muscle endurance, mitochondrial capacity or reperfusion rate.

Conclusions

Adults with T1D did not have reduced oxidative capacity, muscle endurance or muscle reperfusion rates compared to controls. HbA1c also did not correlate with muscle endurance, mitochondrial capacity or reperfusion rates. Future studies should extend these measurements to older people or people with poorly-controlled T1D.

Protocol for randomized controlled trial of electric stimulation with high-volt twin peak versus placebo for facial functional recovery from acute Bell's palsy in patients with poor prognostic factors

BACKGROUND

Electric stimulation (ES) can prevent muscle atrophy and promote tissue healing and therefore may help prevent sequelae of Bell's palsy but due to lack of high-quality studies, the effectiveness of ES in Bell's palsy remains controversial. Here we describe a protocol to evaluate the effects of monophasic high volt ES in patients with Bell's palsy and poor prognosis for recovery.

RESULTS

This is a protocol for a prospective, double-blinded, randomized, placebo-controlled study. Participants include adults with acute Bell's palsy with poor prognosis for full recovery due to complete paralysis or being over age 60. ES will be a monophasic, high-volt pulsed waveform, 100μsec pulse duration, 35 hertz, motor-level intensity. Follow up will be at months 1, 2, 3 and 6. The primary outcome will be the proportion of patients with complete recovery using the eFACES tool. Secondary outcomes include patient reported quality of life measured by FaCE and the synkinesis assessment questionnaires, objective photographs, time to complete recovery, adverse effects, and tolerability.

CONCLUSION

This protocol has the potential to provide high quality evidence regarding the effects, up to 6 months after onset, of pulsed monophasic high-volt ES for patients with acute Bell's palsy and poor prognosis for complete recovery.

Non-linearity of Skin Properties in Electrotactile Applications: Identification and Mitigation

Electrotactile displays can open a new sensory substitution channel to be utilized in a vast array of applications. Our Finger-Eye research used this approach to build a system for the blind to easily read any text not written in Braille. But there are still challenges in different aspects of such systems. One of the most crucial concerns, is the effects of receptor fatigue. Our tests show that during prolonged exposure of receptors to the electrical signals, their sensitivity to the signal level changes gradually and adjustments in the signal's power are required to keep the receptors is the stimulated state. This was confirmed by monitoring the electrical current passing through the skin and calculating the corresponding impedance. More interestingly, the rates of the impedance changes are different for each part of the skin, indicating inconsistent rates of receptor fatigue for each region of the skin. These electrical properties of the skin were addressed in this research for the purpose of rendering consistent sensations for the users regardless of the person or skin conditions. To solve these challenges, two methods are employed: a voltage control system based on pulse-width modulation is used to adjust the signal power; and Kalman filtering is used to predict impedance changes in advance and supply the skin with the proper signal. The result is a self-contained automated system capable of managing the signal power for any user at any given time or skin condition.

Effectiveness of Accelerated Recovery Performance for Post-ACL Reconstruction Rehabilitation

Atrophy and protracted recovery of normal function of the ipsilateral quadriceps femoris muscle following anterior cruciate ligament reconstruction surgery is well documented. The Accelerated Recovery Performance trainer is a type of electrical stimulation device that delivers a high-pulse frequency via a direct current, making it unique from many other devices on the market. The purpose of the present study was to investigate the effects of the direct current (via the Accelerated Recovery Performance trainer protocol) on gains in thigh circumference following anterior cruciate ligament reconstruction. Twenty-five patients were enrolled following isolated anterior cruciate ligament reconstruction and randomly assigned to either an isometric rehabilitation protocol augmented with the Accelerated Recovery Performance trainer protocol (experimental group) or the isometric rehabilitation protocol alone (control group). The two groups participated in sixteen sessions of directed rehabilitation over a two-month time period. Patients were followed with serial thigh circumference measurements at 5, 10, 15, and 20 centimeters above the superior patellar pole. Comparison of the overall mean circumferential gains in thigh circumference of the involved leg demonstrated approximately 3:1 gains in the ARP group over the control group, demonstrating it to be superior to isometric rehabilitation alone with regards to gains in thigh girth. The Accelerated Recovery Performance trainer protocol should be considered for post-anterior cruciate ligament reconstruction rehabilitation in order to reverse disuse atrophy of the ipsilateral quadriceps femoris.

Micropatterned conductive hydrogels as multifunctional muscle-mimicking biomaterials: Graphene-incorporated hydrogels directly patterned with femtosecond laser ablation

Multifunctional biomaterials that can provide physical, electrical, and structural cues to cells and tissues are highly desirable to mimic the important characteristics of native tissues and efficiently modulate cellular behaviors. Especially, electrically conductive biomaterials can efficiently deliver electrical signals to living systems; however, the production of conductive biomaterials presenting multiple cell interactive cues is still a great challenge. In this study, we fabricafed an electrically conductive, mechanically soft, and topographically active hydrogel by micropatterning a graphene oxide (GO)-incorporated polyacrylamide hydrogel (GO/PAAm) with femtosecond laser ablation (FLA) and subsequent chemical reduction. FLA parameters were optimized to efficiently produce distinct line patterns on GO/PAAm hydrogels to induce myoblast alignment and maturation. The line patterns distances (PD) were varied to have different topographies (20-80 μm PD). In vitro studies with C2C12 myoblasts revealed that the micopatterned hydrogels are superior to the unpatterned substrates in inducing myogenesis and myotube alignment. Reduced GO/PAAm with 50 μm PD, i.e., PD50/r(GO/PAAm), showed the best results among the various features for differentiation and myotube alignment. Electrical stimulation of myoblasts on the micropatterned conductive hydrogels further promoted the differentiation of myoblasts. In vivo implantation studies indicated good tissue compatibility of PD50/r(GO/PAAm) samples. Altogether, we successfully demonstrated that the micropatterned r(GO/PAAm) may offer multiple properties capable of positively affecting myoblast responses. This hydrogel may serve as an effective multifunctional biomaterial, which possesses the topography for cell alignment/maturation, mechanical properties of the native skeletal muscle tissue, and desirable electrical conductivity for delivering electrical signals to cells, for various biomedical applications such as muscle tissue scaffolds. STATEMENT OF SIGNIFICANCE: Micropatterned conductive hydrogels were created by polymerization of a graphene oxide-incorporated polyacrylamide hydrogel, micropatterning with femtosecond laser ablation, and chemical reduction, which can mimic important characteristics of native skeletal muscle tissues. The micropatterned conductive hydro-gels promoted myogenesis/alignment, enabled electrical stimulation of myoblasts, and displayed good tissue compatibility, which can therefore serve as a multifunctional biomaterial that is topographically active, mechanically soft, and electrically conductive for delivering multiple cell stimulating signals for potential skeletal muscle tissue engineering applications.

The Virtual Electrode Recording Tool for EXtracellular Potentials (VERTEX) Version 2.0: Modelling in vitro electrical stimulation of brain tissue

Neuronal circuits can be modelled in detail allowing us to predict the effects of stimulation on individual neurons. Electrical stimulation of neuronal circuits in vitro and in vivo excites a range of neurons within the tissue and measurements of neural activity, e.g the local field potential (LFP), are again an aggregate of a large pool of cells. The previous version of our Virtual Electrode Recording Tool for EXtracellular Potentials (VERTEX) allowed for the simulation of the LFP generated by a patch of brain tissue. Here, we extend VERTEX to simulate the effect of electrical stimulation through a focal electric field. We observe both direct changes in neural activity and changes in synaptic plasticity. Testing our software in a model of a rat neocortical slice, we determine the currents contributing to the LFP, the effects of paired pulse stimulation to induce short term plasticity (STP), and the effect of theta burst stimulation (TBS) to induce long term potentiation (LTP).

Effect of Neuronal Excitability in Hippocampal CA1 Area on Auditory Pathway in a Rat Model of Tinnitus

Background:

Tinnitus is a common disorder that causes significant morbidity; however, the neurophysiological mechanism is not yet fully understood. A relationship between tinnitus and limbic system has been reported. As a significant component of the limbic system, the hippocampus plays an important role in various pathological processes, such as emotional disturbance, decreased learning ability, and deterioration of memory. This study was aimed to explore the role of the hippocampus in the generation of tinnitus by electrophysiological technology.

Methods:

A tinnitus model was established in rats through intraperitoneal injection of salicylate (SA). Subsequently, the spontaneous firing rate (SFR) of neurons in the hippocampal CA1 area was recorded with in vivo multichannel recording technology to assess changes in excitability induced by SA. To investigate the effect of excitability changes of hippocampus on the auditory pathway, the hippocampus was electrically stimulated and neural excitability in the auditory cortex (AC) was monitored.

Results:

Totally 65 neurons in the hippocampal CA1 area were recorded, 45 from the SA group (n = 5), and 20 from the saline group (n = 5). Two hours after treatment, mean SFR of neurons in the hippocampal CA1 area had significantly increased from 3.06 ± 0.36 Hz to 9.18 ± 1.30 Hz in the SA group (t = −4.521, P < 0.05), while no significant difference was observed in the saline group (2.66 ± 0.36 Hz vs. 2.16 ± 0.36 Hz, t = 0.902, P > 0.05). In the AC, 79.3% (157/198) of recorded neurons showed responses to electrical stimulation of the hippocampal CA1 area. Presumed pyramidal neurons were excited, while intermediate neurons were inhibited after electrical stimulation of the hippocampus.

Conclusions:

The study shows that the hippocampus is excited in SA-induced tinnitus, and stimulation of hippocampus could modulate neuronal excitability of the AC. The hippocampus is involved in tinnitus and may also have a regulatory effect on the neural center.

Natural Sensations Evoked in Distal Extremities Using Surface Electrical Stimulation

Background:

Electrical stimulation is increasingly relevant in a variety of medical treatments. In this study, surface electrical stimulation was evaluated as a method to non-invasively target a neural function, specifically natural sensation in the distal limbs.

Method:

Electrodes were placed over the median and ulnar nerves at the elbow and the common peroneal and lateral sural cutaneous nerves at the knee. Strength-duration curves for sensation were compared between nerves. The location, modality, and intensity of each sensation were also analyzed. In an effort to evoke natural sensations, several patterned waveforms were evaluated.

Results:

Distal sensation was obtained in all but one of the 48 nerves tested in able-bodied subjects and in the two nerves from subjects with an amputation. Increasing the pulse amplitude of the stimulus caused an increase in the area and magnitude of the sensation in a majority of subjects. A low frequency waveform evoked a tapping or tapping-like sensation in 29 out of the 31 able-bodied subjects and a sensation that could be considered natural in two subjects with an amputation. This waveform performed better than other patterned waveforms that had proven effective during implanted extra-neural stimulation.

Conclusion:

Surface electrical stimulation has the potential to be a powerful, non-invasive tool for activation of the nervous system. These results suggest that a tapping sensation in the distal extremity can be evoked in most able-bodied individuals and that targeting the nerve trunk from the surface is a valid method to evoke sensation in the phantom limb of individuals with an amputation for short term applications.

Tibial Nerve Stimulation to Drive Genital Sexual Arousal in an Anesthetized Female Rat

BACKGROUND

There is clinical evidence that percutaneous tibial nerve stimulation can positively benefit women with female sexual interest/arousal disorder, yet no studies have explored the potential mechanisms further.

AIM

To investigate the effect of tibial nerve stimulation on vaginal blood perfusion (VBP) in an anesthetized rat model.

METHODS

16 ketamine-anesthetized rats were surgically implanted with a nerve cuff electrode on 1 tibial nerve. The tibial nerve was stimulated for 30 minutes continuously or non-continuously at a frequency of 10 to 25 Hz.

OUTCOMES

VBP was measured with laser Doppler flowmetry and analyzed using a wavelet transform of time-frequency representations with a focus on the neurogenic energy range (0.076-0.200 Hz).

RESULTS

25 of 33 (75.8%) stimulation periods had at least a 500% increase in laser Doppler flowmetry neurogenic energy compared with baseline. This increase was most common within 20 to 35 minutes after the start of stimulation. There was no statistically significant difference for frequency used or estrous cycle stage.

CLINICAL TRANSLATION

The results of this study provide further support for percutaneous tibial nerve stimulation as an alternative treatment option for women with genital arousal aspects of female sexual interest/arousal disorder.

STRENGTHS AND LIMITATIONS

This study successfully demonstrates the ability of tibial nerve stimulation to increase VBP. However, further studies to determine parameter optimization and to illuminate neural mechanisms are needed. Further studies also are necessary to determine effects of repeated stimulation sessions.

CONCLUSION

Long-duration tibial stimulation was successful at driving increases in the neurogenic component of VBP, providing evidence that tibial nerve stimulation could be used to treat genital arousal aspects of female sexual interest/arousal disorder by improving pelvic blood flow. Zimmerman LL, Rice IC, Berger MB, Bruns TM. Tibial Nerve Stimulation to Drive Genital Sexual Arousal in an Anesthetized Female Rat. J Sex Med 2018;15:296-303.

Amplitude Modulation-based Electrical Stimulation for Encoding Multipixel Spatiotemporal Visual Information in Retinal Neural Activities

Retinal implants have been developed as a promising way to restore partial vision for the blind. The observation and analysis of neural activities can offer valuable insights for successful prosthetic electrical stimulation. Retinal ganglion cell (RGC) activities have been investigated to provide knowledge on the requirements for electrical stimulation, such as threshold current and the effect of stimulation waveforms. To develop a detailed 'stimulation strategy' for faithful delivery of spatiotemporal visual information to the brain, it is essential to examine both the temporal and spatial characteristics of RGC responses, whereas previous studies were mainly focused on one or the other. In this study, we investigate whether the spatiotemporal visual information can be decoded from the RGC network activity evoked by patterned electrical stimulation. Along with a thorough characterization of spatial spreading of stimulation current and temporal information encoding, we demonstrated that multipixel spatiotemporal visual information can be accurately decoded from the population activities of RGCs stimulated by amplitude-modulated pulse trains. We also found that the details of stimulation, such as pulse amplitude range and pulse rate, were crucial for accurate decoding. Overall, the results suggest that useful visual function may be restored by amplitude modulation-based retinal stimulation.

Realistic Electric Field Mapping of Anisotropic Muscle During Electrical Stimulation Using a Combination of Water Diffusion Tensor and Electrical Conductivity

Purpose

To realistically map the electric fields of biological tissues using a diffusion tensor magnetic resonance electrical impedance tomography (DT-MREIT) method to estimate tissue response during electrical stimulation.

Methods

Imaging experiments were performed using chunks of bovine muscle. Two silver wire electrodes were positioned inside the muscle tissue for electrical stimulation. Electric pulses were applied with a 100-V amplitude and 100-μs width using a voltage stimulator. During electrical stimulation, we collected DT-MREIT data from a 3T magnetic resonance imaging scanner. We adopted the projected current density method to calculate the electric field. Based on the relation between the water diffusion tensor and the conductivity tensor, we computed the position-dependent scale factor using the measured magnetic flux density data. Then, a final conductivity tensor map was reconstructed using the multiplication of the water diffusion tensor and the scale factor.

Results

The current density images from DT-MREIT data represent the internal current flows that exist not only in the electrodes but also in surrounding regions. The reconstructed electric filed map from our anisotropic conductivity tensor with the projected current density shows coverage that is more than 2 times as wide, and higher signals in both the electrodes and surrounding tissues, than the previous isotropic method owing to the consideration of tissue anisotropy.

Conclusions

An electric field map obtained by an anisotropic reconstruction method showed different patterns from the results of the previous isotropic reconstruction method. Since accurate electric field mapping is important to correctly estimate the coverage of the electrical treatment, future studies should include more rigorous validations of the new method through in vivo and in situ experiments.

Navigating the Island of Reil: how to understand the insular cortex

Insular-onset seizures are rare and easily misdiagnosed. In this article, we aim to highlight the often distinctive semiology of seizures involving the insula with reference to three cases. We suggest three points to aid the recognition of seizures involving the insula: (1) Seizures originating in the insula frequently present with a sensation of laryngeal constriction, dyspnoea or unpleasant somatosensory symptoms; (2) Seizures involving the anterior insula may have a silent onset, but tend to propagate rapidly to motor areas causing motor or hypermotor symptoms; (3) Seizures involving the posterior insula cause somatosensory symptoms, which are normally contralateral to the seizure onset.

A Study on the Effect of Electrical Stimulation as a User Stimuli for Motor Imagery Classification in Brain-Machine Interface

Functional Electrical Stimulation (FES) provides a neuroprosthetic interface to non-recovered muscle groups by stimulating the affected region of the human body. FES in combination with Brain-machine interfacing (BMI) has a wide scope in rehabilitation because this system directly links the cerebral motor intention of the users with its corresponding peripheral muscle activations. In this paper, we examine the effect of FES on the electroencephalography (EEG) during motor imagery (left- and right-hand movement) training of the users. Results suggest a significant improvement in the classification accuracy when the subject was induced with FES stimuli as compared to the standard visual one.

Alcohol intoxication following muscle contraction in mice decreases muscle protein synthesis but not mTOR signal transduction

BACKGROUND

Alcohol (ethanol [EtOH]) intoxication antagonizes stimulation of muscle protein synthesis and mammalian target of rapamycin (mTOR) signaling. However, whether the anabolic response can be reversed when alcohol is consumed after the stimulus is unknown.

METHODS

A single bout of electrically stimulated muscle contractions (10 sets of 6 contractions) was induced in fasted male C57BL/6 mice 2 hours prior to alcohol intoxication. EtOH was injected intraperitoneally (3 g/kg), and the gastrocnemius/plantaris muscle complex was collected 2 hours later from the stimulated and contralateral unstimulated control leg.

RESULTS

Muscle contraction increased protein synthesis 28% in control mice, while EtOH abolished this stimulation-induced increase. Further, EtOH suppressed the rate of synthesis ~75% compared to control muscle irrespective of stimulation. This decrease was associated with impaired protein elongation as EtOH increased the phosphorylation of eEF2 Thr(56) . In contrast, stimulation-induced increases in mTOR protein complex-1 (mTORC1) (S6K1 Thr(421) /Ser(424) , S6K1 Thr(389) , rpS6 Ser(240/244) , and 4E-BP1 Thr(37/46) ) and mitogen-activated protein kinase (MAPK) (JNK Thr(183) /Tyr(185) , p38 Thr(180) /Tyr(182) , and rpS6S(235/236) ) signaling were not reversed by acute EtOH.

CONCLUSIONS

These data suggest that EtOH-induced decreases in protein synthesis in fasted mice may be independent of mTORC1 and MAPK signaling following muscle contraction and instead due to the antagonistic actions of EtOH on mRNA translation elongation. Therefore, EtOH suppresses the contraction-induced increase in protein synthesis, and over time has the potential to prevent skeletal muscle hypertrophy induced by repeated muscle contraction.

Sensory axonal dysfunction in cervical radiculopathy

OBJECTIVE

The aim of this study was to evaluate changes in sensory axonal excitability in the distal nerve in patients with cervical radiculopathy.

METHODS

The patients were classified by the findings of cervical MRI into two subgroups: 22 patients with C6/7 root compression and 25 patients with cervical cord and root compression above/at C6/7. Patients were investigated using conventional nerve conduction studies (NCS) and nerve excitability testing. Sensory nerve excitability testing was undertaken with stimulation at the wrist and recording from digit II (dermatome C6/7). The results were compared with healthy controls. Both preoperative and postoperative tests were performed if the patient underwent surgery.

RESULTS

Sensory axonal excitability was significantly different in both cohorts compared with healthy controls, including prolonged strength-duration time constant, reduced S2 accommodation, increased threshold electrotonus hyperpolarisation (TEh (90-100 ms)), and increased superexcitability. The changes in these excitability indices are compatible with axonal membrane hyperpolarisation. In five patients who underwent surgery, the postoperative sensory excitability was tested after 1 week, and showed significant changes in TE (TEh (90-100 ms) and TEh slope, p<0.05) between presurgery and postsurgery.

CONCLUSIONS

The present study demonstrated distal nerve axonal hyperpolarisation in patients with cervical radiculopathy. These findings suggest that the hyperpolarised pattern might be due to Na(+)-K(+) ATPase overactivation induced by proximal ischaemia, or could reflect the remyelinating process. Distal sensory axons were hyperpolarised even though there were no changes in NCS, suggesting that nerve excitability testing may be more sensitive to clinical symptoms than NCS in patients with cervical radiculopathy.

Anatomic correlates of deep brain stimulation electrode impedance

BACKGROUND

The location of the optimal target for deep brain stimulation (DBS) of the subthalamic nucleus (STN) remains controversial. Electrode impedance affects tissue activation by DBS and has been found to vary by contact number, but no studies have examined association between impedance and anatomic location.

OBJECTIVES

To evaluate the relationship between electrode impedance and anatomic contact location, and to assess the clinical significance of impedance.

METHODS

We gathered retrospective impedance data from 101 electrodes in 73 patients with Parkinson's disease. We determined contact location using microelectrode recording (MER) and high-field 7T MRI, and assessed the relationship between impedance and contact location.

RESULTS

For contact location as assessed via MER, impedance was significantly higher for contacts in STN, at baseline (111 Ω vs STN border, p=0.03; 169 Ω vs white matter, p<0.001) and over time (90 Ω vs STN border, p<0.001; 54 Ω vs white matter, p<0.001). Over time, impedance was lowest in contacts situated at STN border (p=0.03). Impedance did not vary by contact location as assessed via imaging. Location determination was 75% consistent between MER and imaging. Impedance was inversely related to absolute symptom reduction during stimulation (-2.5 motor portion of the Unified Parkinson's Disease Rating Scale (mUPDRS) points per 1000 Ω, p=0.01).

CONCLUSIONS

In the vicinity of DBS electrodes chronically implanted in STN, impedance is lower at the rostral STN border and in white matter, than in STN. This finding suggests that current reaches white matter fibres more readily than neuronal cell bodies in STN, which may help explain anatomic variation in stimulation efficacy.

Visual prostheses: the enabling technology to give sight to the blind

Millions of patients are either slowly losing their vision or are already blind due to retinal degenerative diseases such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD) or because of accidents or injuries. Employment of artificial means to treat extreme vision impairment has come closer to reality during the past few decades. Currently, many research groups work towards effective solutions to restore a rudimentary sense of vision to the blind. Aside from the efforts being put on replacing damaged parts of the retina by engineered living tissues or microfabricated photoreceptor arrays, implantable electronic microsystems, referred to as visual prostheses, are also sought as promising solutions to restore vision. From a functional point of view, visual prostheses receive image information from the outside world and deliver them to the natural visual system, enabling the subject to receive a meaningful perception of the image. This paper provides an overview of technical design aspects and clinical test results of visual prostheses, highlights past and recent progress in realizing chronic high-resolution visual implants as well as some technical challenges confronted when trying to enhance the functional quality of such devices.

Cathodic voltage-controlled electrical stimulation of titanium implants as treatment for methicillin-resistant Staphylococcus aureus periprosthetic infections

Effective treatment options are often limited for implant-associated orthopedic infections. In this study we evaluated the antimicrobial effects of applying cathodic voltage-controlled electrical stimulation (CVCES) of -1.8 V (vs. Ag/AgCl) to commercially pure titanium (cpTi) substrates with preformed biofilm-like structures of methicillin-resistant Staphylococcus aureus (MRSA). The in vitro studies showed that as compared to the open circuit potential (OCP) conditions, CVCES of -1.8 V for 1 h significantly reduced the colony-forming units (CFU) of MRSA enumerated from the cpTi by 97% (1.89 × 106 vs 6.45 × 104 CFU/ml) and from the surrounding solution by 92% (6.63 × 105 vs. 5.15 × 104 CFU/ml). The in vivo studies, utilizing a rodent periprosthetic infection model, showed that as compared to the OCP conditions, CVCES at -1.8 V for 1 h significantly reduced MRSA CFUs in the bone tissue by 87% (1.15 × 105 vs. 1.48 × 104 CFU/ml) and reduced CFU on the cpTi implant by 98% (5.48 × 104 vs 1.16 × 103 CFU/ml). The stimulation was not associated with histological changes in the host tissue surrounding the implant. As compared to the OCP conditions, the -1.8 V stimulation significantly increased the interfacial capacitance (18.93 vs. 98.25 μF/cm(2)) and decreased polarization resistance (868,250 vs. 108 Ω-cm(2)) of the cpTi. The antimicrobial effects are thought to be associated with these voltage-dependent electrochemical surface properties of the cpTi.

Effect of Rapid Chilling on Beef Quality and Cytoskeletal Protein Degradation in M. longissimus of Chinese Yellow Crossbred Bulls

The objective of this study was to investigate the effect of rapid chilling (RC) on beef quality and the degradation of cytoskeletal proteins. Twenty Chinese Yellow crossbred bulls were selected and randomly divided into two groups. RC and conventional chilling (CC) were applied to left and right sides of the carcasses respectively after slaughtering. To determine whether electrical stimulation (ES) treatment can alleviate the potential hazard of RC on meat quality, ES was applied to one group. The effects of RC and ES were determined by meat color, shear force and cytoskeletal protein degradation postmortem (PM). The results showed that RC decreased beef tenderness at 1 d and 3 d postmortem, but had no detrimental effect on meat color. Western blotting showed that RC decreased the degradation rate of desmin and troponin-T, but the effects weakened gradually as postmortem aging extended. Degradation rates of both desmin and troponin-T were accelerated by ES. The combination of RC and ES could improve beef color, accelerate degradation rate of cytoskeletal protein and improve beef tenderness.

Deep brain stimulation for tremor resulting from acquired brain injury

OBJECTIVES

To evaluate the efficacy of deep brain stimulation (DBS) in the treatment of tremor resulting from acquired brain injury (ABI).

METHODS

A series of eight consecutive patients with post-ABI tremor were treated with DBS of the ventro-oralis posterior (VOP)/zona incerta (ZI) region, and subsequently underwent blinded assessments using Bain's tremor severity scale.

RESULTS

VOP/ZI DBS produced a mean reduction in tremor severity of 80.75% based on Bain's tremor severity scale, with significant reductions in all five component tremor subscores: rest, postural, kinetic, proximal and distal. No adverse neurological complications were reported, although one patient experienced exacerbation of pre-existing gait ataxia.

CONCLUSION

VOP/ZI stimulation is demonstrated here to be an effective and safe approach for the treatment of post-ABI tremor in the largest series published at the time of writing.

Medical therapy and subthalamic deep brain stimulation in advanced Parkinson's disease: a different long-term outcome?

OBJECTIVES

Few clinical trials reported the comparative short-term efficacy of subthalamic nucleus deep brain stimulation (STN-DBS) versus medical therapy in advanced Parkinson's disease (PD). However, the comparative efficacy, safety and the potential disease-modifying effect of these treatments have not been investigated over a longer follow-up period.

METHODS

In this study, we organised a 'retrospective control group' to compare medical and surgical therapies over a long-term period. We assessed a group of PD patients suitable for STN-DBS but successively treated with medical therapies for reasons not related to PD, and a group of similar consecutive STN-DBS patients. We thus obtained two groups comparable at baseline, which were re-evaluated after an average follow-up of 6 years (range 4-11).

RESULTS

Patients treated with STN-DBS showed a long-lasting superior clinical efficacy on motor fluctuations, with a significant reduction in the average percentage of the waking day spent in 'OFF' and in the duration and disability of dyskinesia. Moreover, operated patients showed a better outcome in the activities of daily living in 'Medication-OFF' condition. On the other hand, a similar progression of motor score and cognitive/behavioural alterations was observed between the two groups, apart from phonemic verbal fluency, which significantly worsened in STN-DBS patients.

CONCLUSIONS

To our knowledge, this is the first long-term comparison between medical and surgical therapies; a superior efficacy of STN-DBS was observed on motor disability, while no significant differences were observed in the progression of motor symptoms and, apart from phonemic verbal fluency, of neuropsychological alterations.

Efficacy of carcass electrical stimulation in meat quality enhancement: a review

The use of electrical stimulation (ES) as a management tool to improve meat quality and efficiency of meat processing is reviewed. The basis of the efficacy of ES is its ability to fast track postmortem glycolysis, which in turn stimulates myriad histological, physical, biochemical, biophysical and physiological changes in the postmortem muscle. Electrical stimulation hastens the onset and resolution of rigor mortis thereby reducing processing time and labor and plays a vital role in improving meat tenderness and other meat quality traits. However, ES may have negative impacts on some meat quality traits such as color stability and water holding capacity in some animals. Electrical stimulation is not an end in itself. In order to achieve the desired benefits from its application, the technique must be properly used in conjunction with various intricate antemortem, perimortem and postmortem management practices. Despite extensive research on ES, the fundamental mechanisms and the appropriate commercial applications remained obscured. In addition, muscles differ in their response to ES. Thus, elementary knowledge of the various alterations with respect to muscle type is needed in order to optimize the effectiveness of ES in the improvement of meat quality.

Transcranial direct current stimulation (tDCS) and language

Transcranial direct current stimulation (tDCS), a non-invasive neuromodulation technique inducing prolonged brain excitability changes and promoting cerebral plasticity, is a promising option for neurorehabilitation. Here, we review progress in research on tDCS and language functions and on the potential role of tDCS in the treatment of post-stroke aphasia. Currently available data suggest that tDCS over language-related brain areas can modulate linguistic abilities in healthy individuals and can improve language performance in patients with aphasia. Whether the results obtained in experimental conditions are functionally important for the quality of life of patients and their caregivers remains unclear. Despite the fact that important variables are yet to be determined, tDCS combined with rehabilitation techniques seems a promising therapeutic option for aphasia.

Effects of Electrical Stimulation on Lipid Oxidation and Warmed-over Flavor of Precooked Roast Beef

Many manufacturing processes damage the structure of meat products and this often contributes to lipid oxidation which could influence warmed-over flavor (WOF) in precooked beef that is reheated beef. Electrical stimulation causes contraction of muscles and improves tissue tenderization. The purpose of this study was to evaluate the rate of lipid oxidation or warmed-over flavor that could be affected by electrical stimulation of precooked roast beef after refrigerated storage and reheating. The results show that there was no significant difference between chemical compositions and cooking yields when comparing non-electrically stimulated and electrically stimulated roast beef. Moreover, electrical stimulation had no significant effect on oxidative stability and off-flavor problems of precooked roast beef as evaluated by thiobarbituric acid reactive substances (TBARS) and sensory test (warmed-over aroma and warmed-over flavor). However, there was an increased undesirable WOF and a decrease in tenderness for both ES and Non-ES treatments over refrigerated storage time. Electrical stimulation did cause reactions of amino acids or other compounds to decrease the desirable beef flavor in re-cooked meat.

Effects of pulse width and electrode placement on the efficacy and cognitive effects of electroconvulsive therapy

BACKGROUND

While electroconvulsive therapy (ECT) in major depression is effective, cognitive effects limit its use. Reducing the width of the electrical pulse and using the right unilateral electrode placement may decrease adverse cognitive effects, while preserving efficacy.

METHODS

In a double-masked study, we randomly assigned 90 depressed patients to right unilateral ECT at 6 times seizure threshold or bilateral ECT at 2.5 times seizure threshold, using either a traditional brief pulse (1.5 ms) or an ultrabrief pulse (0.3 ms). Depressive symptoms and cognition were assessed before, during, and immediately, two, and six months after therapy. Patients who responded were followed for a one-year period.

RESULTS

The final remission rate for ultrabrief bilateral ECT was 35 percent, compared with 73 percent for ultrabrief unilateral ECT, 65 percent for standard pulse width bilateral ECT, and 59 percent for standard pulse width unilateral ECT (all P's<0.05 after covariate adjustment). The ultrabrief right unilateral group had less severe cognitive side effects than the other 3 groups in virtually all primary outcome measures assessed in the acute postictal period, and during and immediately following therapy. Both the ultrabrief stimulus and right unilateral electrode placement produced less short- and long-term retrograde amnesia. Patients rated their memory deficits as less severe following ultrabrief right unilateral ECT compared to each of the other three conditions (P<0.001).

CONCLUSIONS

The use of an ultrabrief stimulus markedly reduces adverse cognitive effects, and when coupled with markedly suprathreshold right unilateral ECT, also preserves efficacy. (ClinicalTrials.gov number, NCT00487500.).

Type of Encouragement Influences Peak Muscle Force in College-Age Women

To investigate if the type of encouragement during a maximal voluntary isometric contraction (MVIC) had an influence on peak muscle force in strength-trained versus untrained collegiate women. Eleven strength-trained (20±1 y) and twelve untrained (21±1 y) women participated in three, five-second MVICs of seated knee extension. The three trials consisted of verbal only encouragement, verbal + visual encouragement, and verbal + pain avoidance encouragement. In all three trials, the participants received the same verbal encouragement. Trials were counterbalanced to minimize any possible order effects. A repeated measure ANOVA was used to analyze data. Any significant main effects were further analyzed using Tukey post hoc tests. There was no interaction between training status and encouragement type for all subjects F(2,42) = 1.5474, p = 0.22). For all subjects, a main effect for encouragement type was detected (F(2,42) = 6.616, p <0.05) with significant differences found in MVIC between the verbal encouragement and verbal + visual feedback (99.5±29 ft-lbs and 115.6±29 ft-lbs, p<0.01). No significant differences were found between the verbal only and the addition of pain avoidance (99.5±29 ft-lbs and 109.9±26.3 ft-lbs, p=0.069) or the visual and pain avoidance trials (115.6±29 ft-lbs and 109.9±26 ft-lbs, p=0.43). In this study, training status did not significantly influence the response to type of encouragement. Individuals produced the most force during a MVIC with verbal and visual encouragement. The incorporation of verbal encouragement and visual feedback is an important factor in eliciting peak force in college-aged women. This may have important implications in training and rehabilitation models that incorporate resistive loading of the skeletal muscles.

Functional and histologic changes after repeated transcranial direct current stimulation in rat stroke model

Transcranial direct current stimulation (tDCS) is associated with enhancement or weakening of the NMDA receptor activity and change of the cortical blood flow. Therefore, repeated tDCS of the brain with cerebrovascular injury will induce the functional and histologic changes. Sixty-one Sprague-Dawley rats with cerebrovascular injury were used. Twenty rats died during the experimental course. The 41 rats that survived were allocated to the exercise group, the anodal stimulation group, the cathodal stimulation group, or the control group according to the initial motor function. Two-week treatment schedules started from 2 days postoperatively. Garcia, modified foot fault, and rota-rod performance scores were checked at 2, 9, and 16 days postoperatively. After the experiments, rats were sacrificed for the evaluation of histologic changes (changes of the white matter axon and infarct volume). The anodal stimulation and exercise groups showed improvement of Garcia's and modified foot fault scores at 16 days postoperatively. No significant change of the infarct volume happened after exercise and tDCS. Neuronal axons at the internal capsule of infarct hemispheres showed better preserved axons in the anodal stimulation group. From these results, repeated tDCS might have a neuroprotective effect on neuronal axons in rat stroke model.

Sacral anterior root stimulated defecation in spinal cord injuries: An experimental study in canine model

AIM: To investigate whether there was a dominant sacral root for the motive function of rectum and anal sphincter, and to provide an experimental basis for sacral root electrically stimulated defecation in spinal cord injuries.

METHODS: Eleven spinal cord injured mongrel dogs were included in the study. After L4-L7 laminectomy, the bilateral L7-S3 roots were electrostimulated separately and rectal and sphincter pressure were recorded synchronously. Four animals were implanted electrodes on bilateral S2 roots.

RESULTS: For rectal motorial innervation, S2 was the most dominant (mean 15.2 kPa, 37.7% of total pressure), S1 (11.3 kPa, 27.6%) and S3 (10.9 kPa, 26.7%) contributed to a smaller part. For external anal sphincter, S3 (mean 17.2 kPa, 33.7%) was the most dominant, S2 (16.2 kPa, 31.6%) and S1 (14.3 kPa, 27.9%) contributed to a lesser but still a significant part. Above 85% L7 roots provided some functional contribution to rectum and anal sphincter. For both rectum and sphincter, the right sacral roots provided more contribution than the left roots. Postoperatively, the 4 dogs had electrically stimulated defecation and micturition under the control of the neuroprosthetic device.

CONCLUSION: S2 root is the most dominant contributor to rectal pressure in dogs. Stimulation of bilateral S2 with implanted electrodes contributes to good micturition and defecation in dogs.