Evidence of the enhancement effect in electrical stimulation via electrode matching (L).
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ABSTRACT:
SUBMITTER: Goupell MJ
PROVIDER: S-EPMC3292600 | biostudies-other | 2012 Feb
REPOSITORIES: biostudies-other
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Project description:PurposeMacrophage accumulation in response to decreasing myonuclei may be the major mechanism underlying immobilization-induced muscle fibrosis in muscle contracture, an intervention strategy suppressing these lesions is necessary. Therefore, this research investigated the effect of belt electrode-skeletal muscle electrical stimulation (B-SES), a new electrical stimulation device, to the macrophage accumulation via myonuclei decrease in immobilization-induced muscle fibrosis.Materials and methods18 Wistar male rats were divided into the control group, immobilization group (with plaster cast fixation to immobilize the soleus muscles in a shortened position for 2 weeks), and B-SES group (with muscle contractile exercise through B-SES during the immobilization period). B-SES stimulation was performed at a frequency of 50 Hz and an intensity of 4.7 mA, muscle contractile exercise by B-SES was applied to the lower limb muscles for 20 minutes/session (twice a day) for 2 weeks (6 times/week). The bilateral soleus muscles were used for histological, immunohistochemical, biochemical, and molecular biological analyses.ResultsThe number of myonuclei was significantly higher in the B-SES group than in the immobilization group, and there was no significant difference between the B-SES and control groups. The cross-sectional area of type I and II myofibers in the immobilization and B-SES groups was significantly lower than that in the control group, and the cross-sectional area of type I myofibers in the B-SES group was higher than that in the immobilization group. However, Atrogin-1 and MuRF-1 mRNA expression in the immobilization and B-SES groups was significantly higher than those in the control group. Additionally, the number of macrophages, IL-1β, TGF-β1, and α-SMA mRNA expression, and hydroxyproline expression was significantly lower in the control and B-SES groups than those in the immobilization group.ConclusionThis research surmised that muscle contractile exercise through B-SES prevented immobilization-induced muscle fibrosis, and this alteration suppressed the development of muscle contracture.
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Project description:The patient's Cr (creatinine), BUN (blood urea nitrogen), HBG (hemoglobin), VT (ventricular tachycardia), pacing frequency, puncture point, emergency to permanent pacing time, pacing current (mA), pacing threshold current (mA), and admission diagnosis data were collected. The data were subjected to frequency statistics, curve regression analysis, PLS regression analysis, adjustment analysis, chi-square test, ridge regression analysis, discriminant analysis, negative binomial regression analysis, Poisson regression analysis, and stepwise regression analysis. Some findings include the following: (1) Cr has a significant positive effect on HBG, and BUN has a significant negative effect on HBG. (2) VT has a negative correlation with age and a positive correlation with CK-MB and CK (creatinine kinase). (3) Myocarditis has a negative correlation with age and a significant positive correlation with CTnI (cardiac troponin I). (4) AST (aspartate transaminase) and ALT (alanine aminotransferase) have a significant positive impact on DDI (D-dimer), while CTnI has a significant negative impact on DDI. MYO (myoglobin) has no impact relationship to DDI. (5) ALT has a significant positive relationship with APTT (partial thromboplastin time). (6) Alb (albumin) and TBIL (total bilirubin) have a significant positive effect on PLT (platelet) count, while pro-BNP (B-type natriuretic peptide) and MYO have a significant negative effect on PLT. (7) CK has a significant positive effect on INR (international normalized ratio). (8) The relationship between sinus node dysfunction and VT significantly affect the pacing frequency (beats/minute). For third-degree atrioventricular block, different samples of sinus node dysfunction showed significant differences. (9) There is a significant positive correlation between pacing current (mA) and pacing threshold current (mA). (10) There was a significant positive correlation between perceived voltage (mV) and the time from emergency to permanent pacing. Admission diagnosis has a significant positive impact on the time from emergency to permanent pacing. The change (increase) in time from emergency to permanent pacing was 1.137-fold when an additional condition was diagnosed on admission.
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Project description:Due to the individual differences controlling brain-computer interfaces (BCIs), the applicability and accuracy of BCIs based on motor imagery (MI-BCIs) are limited. To improve the performance of BCIs, this article examined the effect of transcranial electrical stimulation (tES) on brain activity during MI. This article designed an experimental paradigm that combines tES and MI and examined the effects of tES based on the measurements of electroencephalogram (EEG) features in MI processing, including the power spectral density (PSD) and dynamic event-related desynchronization (ERD). Finally, we investigated the effect of tES on the accuracy of MI classification using linear discriminant analysis (LDA). The results showed that the ERD of the μ and β rhythms in the left-hand MI task was enhanced after electrical stimulation with a significant effect in the tDCS group. The average classification accuracy of the transcranial alternating current stimulation (tACS) group and transcranial direct current stimulation (tDCS) group (88.19% and 89.93% respectively) were improved significantly compared to the pre-and pseudo stimulation groups. These findings indicated that tES can improve the performance and applicability of BCI and that tDCS was a potential approach in regulating brain activity and enhancing valid features during noninvasive MI-BCI processing.
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Project description:The Salience Network (SN) and its interactions are important for cognitive control. We have previously shown that structural damage to the SN is associated with abnormal functional connectivity between the SN and Default Mode Network (DMN), abnormal DMN deactivation, and impaired response inhibition, which is an important aspect of cognitive control. This suggests that stimulating the SN might enhance cognitive control. Here, we tested whether non-invasive transcranial direct current stimulation (TDCS) could be used to modulate activity within the SN and enhance cognitive control. TDCS was applied to the right inferior frontal gyrus/anterior insula cortex during performance of the Stop Signal Task (SST) and concurrent functional (f)MRI. Anodal TDCS improved response inhibition. Furthermore, stratification of participants based on SN structural connectivity showed that it was an important influence on both behavioural and physiological responses to anodal TDCS. Participants with high fractional anisotropy within the SN showed improved SST performance and increased activation of the SN with anodal TDCS, whilst those with low fractional anisotropy within the SN did not. Cathodal stimulation of the SN produced activation of the right caudate, an effect which was not modulated by SN structural connectivity. Our results show that stimulation targeted to the SN can improve response inhibition, supporting the causal influence of this network on cognitive control and confirming it as a target to produce cognitive enhancement. Our results also highlight the importance of structural connectivity as a modulator of network to TDCS, which should guide the design and interpretation of future stimulation studies.
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Project description:The objective of this analysis was to evaluate the effectiveness of deep brain stimulation (DBS) and vagus nerve stimulation (VNS) for the treatment of drug-resistant epilepsy in adults and children.A literature search was performed using MEDLINE, EMBASE, the Cochrane Library, and the Centre for Reviews and Dissemination database, for studies published from January 2007 until December 2012.Systematic reviews, meta-analyses, randomized controlled trials (RCTs), and observational studies (in the absence of RCTs) of adults or children were included. DBS studies were included if they specified that the anterior nucleus of thalamus was the area of the brain stimulated. Outcomes of interest were seizure frequency, health resource utilization, and safety. A cost analysis was also performed.The search identified 6 studies that assessed changes in seizure frequency after electrical stimulation: 1 RCT on DBS in adults, 4 RCTs on VNS in adults, and 1 RCT on VNS in children. The studies of DBS and VNS in adults found significantly improved rates of seizure frequency, but the study of VNS in children did not find a significant difference in seizure frequency between the high and low stimulation groups. Significant reductions in hospitalizations and emergency department visits were found for adults and children who received VNS. No studies addressed the use of health resources for patients undergoing DBS. Five studies reported on adverse events, which ranged from serious to transient for both procedures in adults and were mostly transient in the 1 study of VNS in children.We found no evidence on DBS in children or on health care use related to DBS. The measurement of seizure frequency is self-reported and is therefore subject to bias and issues of compliance.Based on evidence of low to moderate quality, both DBS and VNS seemed to reduce seizure frequency in adults. In children, VNS did not appear to be as effective at reducing seizure frequency, but children had significantly fewer hospitalizations and ED visits after VNS implantation. Despite the considerable risks associated with these invasive procedures, long-term adverse events appear to be limited.Electrical stimulation of specific areas of the brain is a procedure used to control epileptic seizures when more conventional treatments are not working. Most adults and children with epilepsy are able to control their seizures with medication, but for some patients, drugs are not effective and surgery to remove the part of the brain where the seizures start is not an appropriate option. This study looked at the research available on the effectiveness, safety, and cost of two types of electrical stimulation devices currently licensed for treatment of epilepsy for adults and children in Canada: vagus nerve stimulation (VNS) and deep brain stimulation (DBS). Both approaches appear to be effective at reducing the frequency of seizures in adults. However, the evidence on DBS is limited to a single study with adults; we found no studies of DBS with children. Studies on VNS showed that both adults and children had fewer hospitalizations and emergency department visits after the procedure. Both procedures carry serious risks, but several longer-term studies have found that adverse events appear to be limited. The cost of VNS, including the process of assessing whether or not patients are good candidates for the procedure, is estimated to be about $40,000 per person (and higher for DBS because the device is more expensive and the operating time is longer). Of the 70,000 people in Ontario with epilepsy, about 1,400 (300 children and 1,110 adults) may be candidates for VNS to reduce their seizures.
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Project description:Electrical stimulation of specific small fibers (Aδ- and C-fibers) is used in basic studies on nociception and neuropathic pain and to diagnose neuropathies. For selective stimulation of small fibers, the optimal stimulation waveform parameters are an important aspect together with the study of electrode design. However, determining an optimal stimulation condition is challenging, as it requires the characterization of the response of the small fibers to electrical stimulation. The perception thresholds are generally characterized using single-pulse stimulation based on the strength-duration curve. However, this does not account for the temporal effects of the different waveforms used in practical applications. In this study, we designed an experiment to characterize the effects of multiple pulse stimulation and proposed a computational model that considers electrostimulation of fibers and synaptic effects in a multiscale model. The measurements of perception thresholds showed that the pulse dependency of the threshold was an exponential decay with a maximum reduction of 55%. In addition, the frequency dependence of the threshold showed a U-shaped response with a reduction of 25% at 30 Hz. Moreover, the computational model explained the synaptic effects, which were also confirmed by evoked potential recordings. This study further characterized the activation of small fibers and clarified the synaptic effects, demonstrating the importance of waveform selection.
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Project description:ObjectiveTo determine the optimal depth electrode montages for the assessment of effective connectivity based on single-pulse electrical stimulation (SPES). To determine the effect of SPES locations on the extent of resulting neuronal propagations.MethodsWe studied 14 epilepsy patients who underwent invasive monitoring with depth electrodes and measurement of cortico-cortical evoked potentials (CCEPs) and cortico-cortical spectral responses (CCSRs). We determined the effects of electrode montage and stimulus sites on the CCEP/CCSR amplitudes.ResultsBipolar and Laplacian montages effectively reduced the degree of SPES-related signal deflections at extra-cortical levels, including outside the brain, while maintaining those at the cortical level. SPES of structures more proximal to the deep white matter, compared to the cortical surface, elicited greater CCEPs and CCSRs.ConclusionsOn depth electrode recording, bipolar and Laplacian montages are suitable for measurement of near-field CCEPs and CCSRs. SPES of the white matter axons may induce neuronal propagations to extensive regions of the cerebral cortex.SignificanceThis study helps to establish the practical guidelines on the diagnostic use of CCEPs/CCSRs.
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