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.
Existing neuroregulatory techniques can achieve precise stimulation of the whole brain or cortex, but high-focus deep brain stimulation has been a technical bottleneck in this field. In this paper, based on the theory of negative permeability emerged in recent years, a simulation model of magnetic replicator is established to study the distribution of the induced electric field in the deep brain and explore the possibility of deep focusing, which is compared with the traditional magnetic stimulation method. Simulation results show that a single magnetic replicator realized remote magnetic source. Under the condition of the same position and compared with the traditional method of stimulating, the former generated smaller induced electric field which sharply reduced with distance. By superposition of the magnetic field replicator, the induced electric field intensity could be increased and the focus could be improved, reducing the number of peripheral wires while guaranteeing good focus. The magnetic replicator model established in this paper provides a new idea for precise deep brain stimulation, which can be combined with neuroregulatory techniques in the future to lay a foundation for clinical application.
Repeated transcranial magnetic stimulation (rTMS) is one of the commonly used brain stimulation techniques. In order to investigate the effects of rTMS on the excitability of different types of neurons, this study is conducted to investigate the effects of rTMS on the cognitive function of mice and the excitability of hippocampal glutaminergic neurons and gamma-aminobutyric neurons from the perspective of electrophysiology. In this study, mice were randomly divided into glutaminergic control group, glutaminergic magnetic stimulation group, gamma-aminobutyric acid energy control group, and gamma-aminobutyric acid magnetic stimulation group. The four groups of mice were injected with adeno-associated virus to label two types of neurons and were implanted optical fiber. The stimulation groups received 14 days of stimulation and the control groups received 14 days of pseudo-stimulation. The fluorescence intensity of calcium ions in mice was recorded by optical fiber system. Behavioral experiments were conducted to explore the changes of cognitive function in mice. The patch-clamp system was used to detect the changes of neuronal action potential characteristics. The results showed that rTMS significantly improved the cognitive function of mice, increased the amplitude of calcium fluorescence of glutamergic neurons and gamma-aminobutyric neurons in the hippocampus, and enhanced the action potential related indexes of glutamergic neurons and gamma-aminobutyric neurons. The results suggest that rTMS can improve the cognitive ability of mice by enhancing the excitability of hippocampal glutaminergic neurons and gamma-aminobutyric neurons.
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.
Parkinson’s disease is a neurodegenerative disease that mostly occurs in middle-aged and elderly people. It is characterized by progressive loss of dopaminergic neurons in the substantia nigra and aggregation of Lewy bodies, resulting in a series of motor symptoms and non-motor symptoms. Depression is the most important manifestation of non-motor symptoms, which seriously affects the quality of life of patients. Clinicians often use antidepressant drugs to improve the depressive symptoms of patients with Parkinson 's disease, but it is still urgent to solve the problems of drug side effects and drug resistance caused by such methods. Repetitive transcranial magnetic stimulation is a safe and non-invasive neuromodulation technique that can change the excitability of the corticospinal tract, induce the release of dopamine and other neurotransmitters, and further improve the depressive symptoms of patients with Parkinson 's disease. Based on this, this paper discusses and summarizes the research progress on the efficacy and potential mechanism of repetitive transcranial magnetic stimulation for improving depression in Parkinson 's disease at home and abroad, in order to provide reference for related clinical application research.
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.
ObjectiveTo systematically review the efficacy of repetitive transcranial magnetic stimulation (rTMS) on patients with mild cognitive impairment (MCI). MethodsWe searched databases including PubMed, The Cochrane Library (Issue 10, 2015), EMbase, PsycINF, EBSCO, CBM, CNKI, WanFang Data and VIP from inception to October 2015 to collect randomized controlled trials (RCTs) about rTMS for patients with MCI. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then, meta-analysis was performed by using RevMan 5.3 software. ResultsA total of 5 RCTs involving 180 MCI patients were included. The results of meta-analysis showed that, compared with the control group, rTMS treatment could significantly improve the overall cognitive abilities of MCI patients (SMD=2.53, 95% CI 0.91 to 4.16, P=0.002), as well as the single-domain cognitive performances, including tests for episodic memory (MD=0.98, 95% CI 0.24 to 1.72, P=0.01) and verbal fluency (MD=2.08, 95% CI 0.46 to 3.69, P=0.01). rTMS was a well-tolerated therapy, with slightly more adverse events observed than the control group (RD=0.09, 95% CI 0.00 to 0.18, P=0.04), but cases were mainly transient headache, dizziness and scalp pain. ConclusionrTMS may benefit the cognitive abilities of MCI patients. Nevertheless, due to the limited quantity and quality of included studies, large-scale, multicenter, and high quality RCTs are required to verify the conclusion.
Weightlessness in the space environment affects astronauts’ learning memory and cognitive function. Repetitive transcranial magnetic stimulation has been shown to be effective in improving cognitive dysfunction. In this study, we investigated the effects of repetitive transcranial magnetic stimulation on neural excitability and ion channels in simulated weightlessness mice from a neurophysiological perspective. Young C57 mice were divided into control, hindlimb unloading and magnetic stimulation groups. The mice in the hindlimb unloading and magnetic stimulation groups were treated with hindlimb unloading for 14 days to establish a simulated weightlessness model, while the mice in the magnetic stimulation group were subjected to 14 days of repetitive transcranial magnetic stimulation. Using isolated brain slice patch clamp experiments, the relevant indexes of action potential and the kinetic property changes of voltage-gated sodium and potassium channels were detected to analyze the excitability of neurons and their ion channel mechanisms. The results showed that the behavioral cognitive ability and neuronal excitability of the mice decreased significantly with hindlimb unloading. Repetitive transcranial magnetic stimulation could significantly improve the cognitive impairment and neuroelectrophysiological indexes of the hindlimb unloading mice. Repetitive transcranial magnetic stimulation may change the activation, inactivation and reactivation process of sodium and potassium ion channels by promoting sodium ion outflow and inhibiting potassium ion, and affect the dynamic characteristics of ion channels, so as to enhance the excitability of single neurons and improve the cognitive damage and spatial memory ability of hindlimb unloading mice.
ObjectiveTo observe the efficacy of high-frequency repetitive transcranial magnetic stimulation (rTMS) applied at contralesional hemisphere Broca’s homologue on patients with global aphasia after left massive cerebral infarction. Methods Patients with global aphasia after left massive cerebral infarction in the Department of Neurorehabilitation of China Rehabilitation Research Center between August 2021 and December 2023 were selected. According to the random number table method, patients were randomly divided into a low-frequency rTMS group and a high-frequency rTMS group. rTMS targeted the mirror area within the right hemispheric Broca’s area. Patients’ language ability was assessed pre- and post-treatment by the Chinese version of the western aphasia battery (WAB). Results A total of 27 patients were included, with 14 in the low-frequency rTMS group and 13 in the high-frequency rTMS group. Before treatment, there was no statistically significant difference in the WAB test indicators between the two groups of patients (P>0.05). After treatment, WAB scores (spontaneous speech, auditory comprehension, naming, repetition, aphasia quotients) in both groups were significantly improved (P<0.05); compared to the low-frequency rTMS group, the high-frequency rTMS group exhibited significant improvement in spontaneous speech, auditory comprehension, repetition, naming and aphasia quotients (P<0.05). Conclusion The effect of high-frequency rTMS excitation to contralesional hemisphere is better than that of conventional low-frequency rTMS inhibition to contralesional hemisphere in improving the speech function of patients with global aphasia after left massive cerebral infarction.
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.