Pain is one of the common complications of most diseases. Due to the unknown mechanism of pain, its treatment has been controversial. Repeated peripheral magnetic stimulation for pain has the advantages of non-invasiveness, painlessness, and well-targeted. However, the parameters of repeated peripheral magnetic stimulation for pain are not uniform due to various factors such as frequency, location of action, and coil type. In this paper, the parameters and efficacy of repeated peripheral magnetic stimulation for various kinds of pain such as acute and chronic low back pain, myofascial pain, migraine, peripheral neuralgia and post-traumatic pain are described, in order to providea theoretical basis for future research. In addition, the mechanism of repeated peripheral magnetic stimulation for pain has not been known, and this article will briefly summarize and explain on this.
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.
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.
Non-invasive brain stimulation is a technology that uses magnetic field or electric field to act on the brain to adjust the activity of cerebral cortex neurons. It mainly includes transcranial magnetic stimulation and transcranial direct current stimulation. The principle is to accelerate the induction of neuroplasticity by changing the excitability of the cerebral cortex. The characteristics are noninvasive, safe and that the patient can tolerate it. This article mainly introduces the theoretical foundation and mechanisms of non-invasive brain stimulation, and its application and safety in stroke complications, neuropathic pain and epilepsy, and discusses the commonly used treatment regimens of non-invasive brain stimulation in different neurological diseases, in order to provide possible treatment reference for the rehabilitation of neurological diseases.
Stroke has the characteristics of high incidence rate, high mortality rate and high disability rate. Most patients may have some motor dysfunction after stroke, which greatly affects the normal life of patients. As a common sequela after stroke, foot drop seriously affects the walking gait of patients, limits the activities of patients, and reduces their quality of life. In recent years, repetitive peripheral magnetic stimulation (rPMS) has been used more and more in the rehabilitation of various diseases. Because rPMS is noninvasive, affordable and effective, it is accepted by many patients. This article reviews the research progress of rPMS for foot drop after stroke.
Transcranial magnetic stimulation (TMS), a widely used neuroregulatory technique, has been proven to be effective in treating neurological and psychiatric disorders. The therapeutic effect is closely related to the intracranial electric field caused by TMS, thus accurate measurement of the intracranial electric field generated by TMS is of great significance. However, direct intracranial measurement in human brain faces various technical, safety, ethical and other limitations. Therefore, we have constructed a brain phantom that can simulate the electrical conductivity and anatomical structure of the real brain, in order to replace the clinical trial to achieve intracranial electric field measurement. We selected and prepared suitable conductive materials based on the electrical conductivity of various layers of the real brain tissue, and performed image segmentation, three-dimensional reconstruction and three-dimensional printing processes on each layer of tissue based on magnetic resonance images. The production of each layer of tissue in the brain phantom was completed, and each layer of tissue was combined to form a complete brain phantom. The induced electric field generated by the TMS coil applied to the brain phantom was measured to further verify the conductivity of the brain phantom. Our study provides an effective experimental tool for studying the distribution of intracranial electric fields caused by TMS.
ObjectivesTo systematically review the efficacy of repetitive transcranial magnetic stimulation (rTMS) on rehabilitation of unilateral neglect in stroke patients.MethodsPubMed, The Cochrane Library, PEDro, EMbase, CNKI, WanFang Data and VIP databases were searched online for randomized controlled trials (RCTs) of rTMS on rehabilitation of unilateral neglect in stroke patients from inception to March 2017. Two reviewers independently screened literature, extracted data and assessed the quality of included studies. Meta-analysis was then performed by using RevMan 5.3 software.ResultsA total of 12 RCTs involving 303 patients were included. The results of meta-analysis showed that: the stimulate group was superior to the control group in line bisection test (MD=–5.54, 95%CI –6.79 to –4.29, P<0.000 01), line cancellation test (MD=–3.75, 95%CI –4.60 to –2.90,P<0.000 1) and star cancellation test (MD=–22.94, 95%CI –26.52 to –19.35,P<0.000 01). However, there was no significant difference in the score of the modified Barthel index between two groups (MD=3.91, 95%CI–9.52 to 17.34,P=0.57).ConclusionsrTMS appears to improve the symptoms of unilateral neglect in stroke patients. Due to limited quality and quantity of the included studies, more high quality studies are needed to verify above conclusions.
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.
Repetitive transcranial magnetic stimulation (rTMS) can influence the stimulated brain regions and other distal brain regions connecting to them. The purpose of the study is to investigate the effects of low-frequency rTMS over primary motor cortex on brain by analyzing the brain functional connectivity and coordination between brain regions. 10 healthy subjects were recruited. 1 Hz rTMS was used to stimulate primary motor cortex for 20 min. 1 min resting state electroencephalography (EEG) was collected before and after the stimulation respectively. By performing phase synchronization analysis between the EEG electrodes, the brain functional network and its properties were calculated. Signed-rank test was used for statistical analysis. The result demonstrated that the global phase synchronization in alpha frequency band was decreased significantly after low-frequency rTMS (P<0.05). The phase synchronization was down-regulated between motor cortex and ipsilateral frontal/parietal cortex, and also between contralateral parietal cortex and bilateral frontal cortex. The mean degree and global efficiency of brain functional networks in alpha frequency band were significantly decreased (P<0.05), and the mean shortest path length were significantly increased (P<0.05), which suggested the information transmission of the brain networks and its efficiency was reduced after low-frequency rTMS. This study verified the inhibition function of the low-frequency rTMS to brain activities, and demonstrated that low-frequency rTMS stimulation could affect both stimulating brain regions and distal brain regions connected to them. The findings in this study could be of guidance to clinical application of low-frequency rTMS.
Transcranial magnetic stimulation (TMS) combined with electroencephalography(EEG) has become an important tool in brain research. However, it is difficult to remove the large artifacts in EEG signals caused by the online TMS intervention. In this paper, we summed up various types of artifacts. After introducing a variety of online methods, the paper emphasized on offline approaches, such as subtraction, principal component analysis and independent component analysis, which can remove or minimize TMS-induced artifacts according to their different characteristics. Although these approaches can deal with most of the artifacts induced by TMS, the removal of large artifacts still needs to be improved. This paper systematically summarizes the effective methods for artifacts removal in TMS-EEG studies. It is a good reference for TMS-EEG researchers while choosing the suitable artifacts removal methods.