As a noninvasive neuromodulation technique, transcranial magnetic stimulation (TMS) is widely used in the clinical treatment of neurological and psychiatric diseases, but the mechanism of its action is still unclear. The purpose of this paper is to investigate the effects of different frequencies of magnetic stimulation (MS) on neuronal excitability and voltage-gated potassium channels in the in vitro brain slices from the electrophysiological perspective of neurons. The experiment was divided into stimulus groups and control group, and acute isolated mice brain slices were applied to MS with the same intensity (0.3 T) at different frequencies (20 Hz and 0.5 Hz, 500 pulses) respectively in the stimulus groups. The whole-cell patch clamp technique was used to record the resting membrane potential (RMP), action potential (AP), voltage-gated potassium channels current of hippocampal dentate gyrus (DG) granule cells. The results showed that 20 Hz MS significantly increased the number of APs released and the maximum slope of a single AP, reduced the threshold of AP, half width and time to AP peak amplitude, and improved the excitability of hippocampal neurons. The peak currents of potassium channels were decreased, the inactivation curve of transient outward potassium channels shifted to the left significantly, and the time constant of recovery after inactivation increased significantly. 0.5 Hz MS significantly inhibited neuronal excitability and increased the peak currents of potassium channels, but the dynamic characteristics of potassium channels had little change. The results suggest that the dynamic characteristics of voltage-gated potassium channels and the excitability of hippocampal DG granule neurons may be one of the potential mechanisms of neuromodulation by MS.
Currently, transcranial magnetic stimulation (TMS) has been widely used in the treatment of depression, Parkinson’s disease and other neurological diseases. To be able to monitor the brain’s internal activity during TMS in real time and achieve better treatment outcomes, the researchers proposed combining TMS with neuroimaging methods such as magnetic resonance imaging (MRI), both of which use Tesla-level magnetic fields. However, the combination of strong current, large magnetic field and small size is likely to bring physical concerns which can lead to mechanical and thermal instability. In this paper, the MRI static magnetic field, the TMS coil and human head model were built according to the actual situations. Through the coupling of the magnetic field and the heat transfer module in the finite element simulation software COMSOL, the force and temperature of the TMS coil and head were obtained when the TMS was used in combination with MRI (TMS-MRI technology). The results showed that in a 3 T MRI environment, the maximum force density on the coil could reach 2.51 × 109 N/m3. Both the direction of the external magnetic field and the current direction in the coil affected the force distributions. The closer to the boundary of the external magnetic field, the greater the force. The magnetic field generated by the coil during TMS treatment increased the temperature of the brain tissue by about 0.16 °C, and the presence of the MRI static magnetic field did not cause additional thermal effects. The results of this paper can provide a reference for the development of the use guidelines and safety guidelines of TMS-MRI technology.
In the treatment of drug-refractory epilepsy in children, surgical treatment has a good clinical effect. However, for children whose surgical site is difficult to determine and who cannot undergo resectional surgery, neuromodulation techniques are one of the treatments that can be considered. At present, new neuromodulation technologies in children mainly include transcutaneous vagus nerve stimulation (transcutaneous auricular vagus nerve stimulation, ta-VNS), deep brain stimulation (deep brain stimulation, DBS), reactive nerve stimulation (responsive neurostimulation, RNS), transcranial magnetic stimulation (transcranial magnetic stimulation, TMS), transcranial direct current stimulation (transcranial direct current stimulation, TDCS) and transcranial alternating current stimulation (transcranial alternating current stimulation, TACS). This article briefly discussed the clinical efficacy and safety of various currently available neuromodulation technologies, so as to provide a reference for the rational selection and application of neuromodulation technologies, and improve the clinical efficacy and quality of life of children with drug-refractory epilepsy.
Transcranial magnetic stimulation (TMS) as a non-invasive neuroregulatory technique has been applied in the clinical treatment of neurological and psychiatric diseases. However, the stimulation effects and neural regulatory mechanisms of TMS with different frequencies and modes are not yet clear. This article explores the effects of different frequency repetitive transcranial magnetic stimulation (rTMS) and burst transcranial magnetic stimulation (bTMS) on memory function and neuronal excitability in mice from the perspective of neuroelectrophysiology. In this experiment, 42 Kunming mice aged 8 weeks were randomly divided into pseudo stimulation group and stimulation groups. The stimulation group included rTMS stimulation groups with different frequencies (1, 5, 10 Hz), and bTMS stimulation groups with different frequencies (1, 5, 10 Hz). Among them, the stimulation group received continuous stimulation for 14 days. After the stimulation, the mice underwent new object recognition and platform jumping experiment to test their memory ability. Subsequently, brain slice patch clamp experiment was conducted to analyze the excitability of granulosa cells in the dentate gyrus (DG) of mice. The results showed that compared with the pseudo stimulation group, high-frequency (5, 10 Hz) rTMS and bTMS could improve the memory ability and neuronal excitability of mice, while low-frequency (1 Hz) rTMS and bTMS have no significant effect. For the two stimulation modes at the same frequency, their effects on memory function and neuronal excitability of mice have no significant difference. The results of this study suggest that high-frequency TMS can improve memory function in mice by increasing the excitability of hippocampal DG granule neurons. This article provides experimental and theoretical basis for the mechanism research and clinical application of TMS in improving cognitive function.
ObjectiveTo monitor the diaphragm function of mechanical ventilated patients in the intensive care unit. MethodsA prospective study was conducted on mechanical ventilation patients who had been evaluated by ventilation weaning screening test and planning to underwent spontaneous breathing trial between May 2013 and November 2013. A newly designed multi-function esophageal electrode was used to record the phrenic nerve conduction time (PNCT),diaphragm compound muscle action potential (CMAP) and twitch transdiaphragmatic pressure (TwPdi) elicited by bilateral anterolateral magnetic phrenic nerve stimulation. Results14 patients were recruited in this study. 1 case exited because of intolerance of repetitive magnetic stimulation,2 cases had no diaphragmatic electromyographic signals nor twitch signals,1 case had diaphragmatic electromyographic signal but could not be elicited by magnetic stimulation,1 case had no available TwPdi value with PNCT of 7.2 ms and CMAP of 1.26 mV. In the rest 9 cases,the PNCT,CMAP and TwPdi were (8.5±1.5)ms,(1.01±0.35)mV,(11.2±4.7)cm H2O,respectively. ConclusionNewly designed multi-function esophageal electrode catheter combined with bilateral anterolateral magnetic phrenic nerve stimulation can be used for non-volitional comprehensive assessment of diaphragm in critically ill patients,but not suitable for all subjects.
Objective To evaluate the effectiveness of repetitive transcranial magnetic stimulation (rTMS) for treating dysfunction in patients with Parkinson’s disease (PD). Methods We searched the Cochrane Library (Issue 1, 2010), MEDLINE, EMbase, CBMdisc, and CNKI from the date of the database establishment to April 2010. Randomized controlled trials (RCTs) of rTMS for patients with PD were collected. The quality of the included RCTs was critically appraised and data were extracted by two reviewers independently. Meta-analyses were conducted for the eligible RCTs. Results Eight RCTs were included. The pooled results of the first 2 RCTs showed that, there was no significant difference compared with control group about treating PD patients with clinical motor dysfunction by high-frequency rTMS 10 days later (WMD= –4.75, 95%CI –13.73 to 4.23). The pooled analysis of another 3 studies showed that, no significant difference were found about improving symptoms with treatment of low-frequency rTMS for 1 month compared with control group (WDM= –8.51, 95%CI –18.48 to 1.46). The pooled analysis of last 3 studies showed that, patient with treatment of low-frequency rTMS for 3 months, had been significantly improved in clinical symptoms such as neurological, behavior and emotional state, clinical motor function, and activities of daily living (WDM= –5.79, 95%CI –8.44 to –1.13). The frontal or motor cortex rTMS manifested as low frequency (≤1Hz), high intensity (≥90% RMT), multi-frequency (≥3 times) and long time (≥3 months) had a positive effect on the clinical symptoms of patients with PD and also had a long-term effect. Conclusions rTMS can improve clinical symptoms and dysfunction of the patients with PD.
In order to explore effective ways to reduce non-suicidal self-injury (NSSI) among female adolescents, a total of 45 female adolescent patients with NSSI in West China Hospital of Sichuan University and Guizhou Second Provincial People's Hospital from June 2021 to June 2024 were selected randomly that divided into groups A, B and C, with 15 cases in each group. Group A was treated with repeated transcranial magnetic stimulation (rTMS) and bipolar depression triple therapy, and group B was treated with bipolar depression triple therapy to compare the effectiveness and safety. Group C received bipolar depression triple therapy combined with sham stimulation which only produced stimulating sounds but no stimulating magnetic field as a control in the study. After treatment, the Hamilton Anxiety Score (HAMA), Hamilton Depression Score (HAMD) and Nurses’ Global Assessment of Suicide Risk (NGASR) in group A were significantly lower than those in group B and C (P < 0.01). rTMS combined with bipolar depression triple therapy has a definite effect on reducing NSSI in female adolescents, which can reduce the incidence rate of short-term NSSI behavior in patients.
ObjectiveTo systematically evaluate the effect of repeated transcranial magnetic stimulation (rTMS) in treating epilepsy.MethodsThe randomized controlled trials (RCTs) of rTMS for epilepsy and related diseases were collected from PubMed, EMbase, Cochrane Library, CBM, CNKI, VIP, and Wanfang databases by computer. The retrieval time was from establishment to June 2019. Two researchers independently screened the literature, extracted the data and evaluated the deviation risks of the included studies. RevMan5.3 software was used for Meta analysis.ResultsA total of 21 RCTs were included, including 1 587 patients. The results showed that rTMS assisted antiepileptics drugs (AEDs) could improve the effective rate of epilepsy treatment [RR=1.28, 95% CI (1.19, 1.37)], significantly reduced HAMA, HAMD and NFDS scores in the treatment of patients with epilepsy combined with anxiety and depression [MD=−3.94, 95% CI (−4.25, −3.63)], and improve DQ and GMFM-88 scores in children with cerebral palsy combined with epilepsy [MD=7.95, 95% CI (7.00, 8.90)]. In addition, using rTMS will not cause additional adverse reaction [peto OR=0.52, 95% CI (0.31, 0.84)].ConclusionsThe current evidence showed that rTMS combined AEDs can improve the efficient of AEDs therapy. When treat anxiety depression comorbidity, it can significantly reduce the anxiety depression score. In addition in children with cerebral palsy merger, it can improve muscle strength and development. And rTMS will not cause additional adverse reactions. Limited by the quantity and quality of the selected studies, the conclusions need to be verified by more high-quality studies.
ObjectiveTo systematically evaluate the effect of repetitive transcranial magnetic stimulation (rTMS) on post-stroke depression (PSD).MethodsWe searched databases including the PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Internet, Wanfang, China Biology Medicine database and VIP database to collect randomized controlled trials comparing the effect of the rTMS group and the control group with the scores of depression scale from January 2013 to April 2018. Patients in the rTMS group received rTMS plus drug therapy or conventional treatment for PSD, and patients in the control group received rTMS sham stimulation or not, but the drug treatment or routine treatment was required. When the quality evaluation and data extraction were carried out by two reviewers independently, the Meta-analysis was performed using RevMan 5.3 software and Stata 14.0 software.ResultsA total of 18 literatures involving 1 376 patients (687 patients in the rTMS group and 689 patients in the control group) with PSD were included in this Meta-analysis. Compared with the control group, the rTMS group could effectively reduce the depression scores of PSD patients [standard mean difference (SMD)=–1.13, 95% confidence interval (CI) (–1.42, –0.84), P<0.000 01], and the effective rate of rTMS was 91.7%; meanwhile, rTMS could promote the scores of the National Institute of Health Stroke Scale and the activities of daily living of patients with PSD [SMD=–1.00, 95%CI (–1.25, –0.75), P<0.000 01;SMD=1.56, 95%CI (0.80, 2.32), P<0.000 01]. The source of heterogeneity was not found according to subgroup analysis and Meta-regression analysis. Additionally, few studies reported adverse reactions after the treatment of rTMS.ConclusionsrTMS has a positive effect on depression, neurological deficits, and decreased ability of daily living in patients with PSD. Due to the quality of the included studies, the conclusions need to be verified further.
ObjectiveTwitch transdiaphragmatic pressure is used to evaluate the diaphragm function of mechanical ventilated chronic obstructive pulmonary disease patients before weaning in the intensive care unit, and compared with healthy normal values.MethodsPatients were recruited if they were with acute exacerbation of chronic obstructive pulmonary disease, admitted between May to November in 2013 and December 2014 to February 2016 to the intensive care unit in the First Affiliated Hospital of Guangzhou Medical University, intubated and mechanical ventilated more than 72 hours, and recovered to the clinical stability states after passing the readiness to wean, getting ready for spontaneous breathing test. The newly designed esophageal electrode catheter and bilateral anterolateral magnetic phrenic nerves stimulation were utilized to detect the twitch transdiaphragmatic pressure. At the same time, the function of diaphragm was detected in 10 healthy adults for comparison.ResultsTwenty-two patients were recruited in this study. Two cases had no twitch signals. In the rest 20 cases, the twitch transdiaphragmatic pressure was (7.6±2.5) cm H2O. In 10 healthy adults, twitch transdiaphragmatic pressure was (26.7±4.9) cm H2O. There was significant difference between the patients and the health control subjects (P<0.05).ConclusionTwitch transdiaphragmatic pressure is significantly decreased in weaning chronic obstructive pulmonary disease patients compared with healthy adults.