Ultrasound has emerged as a non-invasive neural modulation technique. Its mechanisms of action in the brain involve mechanical, cavitation, and thermal effects, which modulate neural activity by activating mechanosensitive ion channels, enhancing cell permeability, and improving blood circulation. The ultrasound-piezo-electric systems, based on the coupling between ultrasound and piezoelectric materials, can generate wireless electrical stimulation to promote neural repair, significantly improving therapeutic outcomes for neurodegenerative diseases and showing potential as a replacement for traditional invasive deep brain stimulation techniques. The ultrasound-responsive piezoelectric drug delivery system combines mechano-electrical conversion capability of piezoelectric materials with the non-invasive penetration advantage of ultrasound. This system achieves synergistic therapeutic effects for neurodegenerative diseases through on-demand drug release and wireless electrical stimulation in deep brain regions. It can effectively overcome the blood-brain barrier limitation, enabling precisely targeted drug delivery to specific brain regions. Simultaneously, it generates electrical stimulation in deep brain areas to exert synergistic neuroreparative effects. Together, these capabilities provide a more precise, efficient, and safe solution for treating neurodegenerative diseases. This review summarizes the neural regulatory mechanisms, technical advantages, and research progress of the ultrasound-responsive piezoelectric drug delivery systems for neurodegenerative disease therapy, aiming to offer novel insights for the field.
Humans ; Neurodegenerative Diseases/drug therapy* ; Drug Delivery Systems/methods* ; Blood-Brain Barrier ; Ultrasonic Waves ; Brain ; Ultrasonic Therapy ; Deep Brain Stimulation/methods*

Temporal interference (TI) is a form of stimulation that epitomizes an innovative and non-invasive approach for profound neuromodulation of the brain, a technique that has been validated in mice. Yet, the thin cranial bone structure of mice has a marginal influence on the effect of the TI technique and may not effectively showcase its effectiveness in larger animals. Based on this, we carried out TI stimulation experiments on rats. Following the TI intervention, analysis of electrophysiological data and immunofluorescence staining indicated the generation of a stimulation focus within the nucleus accumbens (depth, 8.5 mm) in rats. Our findings affirm the viability of the TI methodology in the presence of thick cranial bones, furnishing efficacious parameters for profound stimulation with TI administered under such conditions. This experiment not only sheds light on the intervention effects of TI deep in the brain but also furnishes robust evidence in support of its prospective clinical utility.
Animals ; Deep Brain Stimulation/methods* ; Nucleus Accumbens/physiology* ; Male ; Rats ; Rats, Sprague-Dawley ; Time Factors

Transcranial electric stimulation (TES) is a non-invasive, economical, and well-tolerated neuromodulation technique. However, traditional TES is a whole-brain stimulation with a small current, which cannot satisfy the need for effectively focused stimulation of deep brain areas in clinical treatment. With the deepening of the clinical application of TES, researchers have constantly investigated new methods for deeper, more intense, and more focused stimulation, especially multi-electrode stimulation represented by high-precision TES and temporal interference stimulation. This paper reviews the stimulation optimization schemes of TES in recent years and further analyzes the characteristics and limitations of existing stimulation methods, aiming to provide a reference for related clinical applications and guide the following research on TES. In addition, this paper proposes the viewpoint of the development direction of TES, especially the direction of optimizing TES for deep brain stimulation, aiming to provide new ideas for subsequent research and application.
Transcranial Direct Current Stimulation/methods* ; Deep Brain Stimulation ; Brain/physiology* ; Head ; Electric Stimulation/methods*

Tinnitus is defined as a perception of sound without any external sound source. Chronic tinnitus is a frequent condition that can affect the quality of life. So far, no causal cure for tinnitus has been documented, and most pharmacologic and psychosomatic treatment modalities aim to diminish tinnitus' impact on the quality of life. Neuromodulation, a novel therapeutic modality, which aims at alternating nerve activity through a targeted delivery of a stimulus, has emerged as a potential option in tinnitus treatment. This review provides a brief overview of the current neuromodulation techniques as tinnitus treatment options. The main intention is to provide updated knowledge especially for medical professionals counselling tinnitus patients in this emerging field of medicine. Non-invasive methods such as repetitive transcranial magnetic stimulation, transcranial electrical stimulation, neurofeedback, and transcutaneous vagus nerve stimulation were included, as well as invasive methods such as implanted vagus nerve stimulation and invasive brain stimulation. Some of these neuromodulation techniques revealed promising results; nevertheless, further research is needed, especially regarding the pathophysiological principle as to how these neuromodulation techniques work and what neuronal change they induce. Various studies suggest that individually different brain states and networks are involved in the generation and perception of tinnitus. Therefore, in the future, individually tailored neuromodulation strategies could be a promising approach in tinnitus treatment for achieving a more substantial and longer lasting improvement of complaints.
Deep Brain Stimulation/methods* ; Humans ; Neurofeedback/methods* ; Tinnitus/therapy* ; Transcranial Direct Current Stimulation/methods* ; Transcranial Magnetic Stimulation/methods* ; Vagus Nerve Stimulation/methods*

Deep brain stimulation (DBS) surgery is an important treatment for patients with Parkinson's disease in the middle and late stages. The accuracy of the implantation of electrode at the location of the nuclei directly determines the therapeutic effect of the operation. At present, there is no single imaging method that can obtain images with electrodes, nuclei and their positional relationship. In addition, the subthalamic nucleus is small in size and the boundary is not obvious, so it cannot be directly segmented. In this paper, a complete end-to-end DBS effect evaluation pipeline was constructed using magnetic resonance (MR) data of T1, T2 and SWI weighted by DBS surgery. Firstly, the images of preoperative and postoperative patients are registered and normalized to the same coordinate space. Secondly, the patient map is obtained by non-rigid registration of brain map and preoperative data, as well as the preoperative nuclear cluster prediction position. Then, a three-dimensional (3D) image of the positional relationship between the electrode and the nucleus is obtained by using the electrode path in the postoperative image and the result of the nuclear segmentation. The 3D image is helpful for the evaluation of the postoperative effect of DBS and provides effective information for postoperative program control. After analysis, the algorithm can achieve a good registration between the patient's DBS surgical image and the brain map. The error between the algorithm and the expert evaluation of the physical coordinates of the center of the thalamus is (1.590 ± 1.063) mm. The problem of postoperative evaluation of the placement of DBS surgical electrodes is solved.
Brain Mapping ; methods ; Deep Brain Stimulation ; Electrodes, Implanted ; Humans ; Imaging, Three-Dimensional ; Magnetic Resonance Imaging ; Multimodal Imaging ; Parkinson Disease ; surgery ; Subthalamic Nucleus

The electrical conductivity is a passive material property primarily determined by concentrations of charge carriers and their mobility. The macroscopic conductivity of a biological tissue at low frequency may exhibit anisotropy related with its structural directionality. When expressed as a tensor and properly quantified, the conductivity tensor can provide diagnostic information of numerous diseases. Imaging conductivity distributions inside the human body requires probing it by externally injecting conduction currents or inducing eddy currents. At low frequency, the Faraday induction is negligible and it has been necessary in most practical cases to inject currents through surface electrodes. Here we report a novel method to reconstruct conductivity tensor images using an MRI scanner without current injection. This electrodeless method of conductivity tensor imaging (CTI) utilizes B1 mapping to recover a high-frequency isotropic conductivity image which is influenced by contents in both extracellular and intracellular spaces. Multi-b diffusion weighted imaging is then utilized to extract the effects of the extracellular space and incorporate its directional structural property. Implementing the novel CTI method in a clinical MRI scanner, we reconstructed in vivo conductivity tensor images of canine brains. Depending on the details of the implementation, it may produce conductivity contrast images for conductivity weighted imaging (CWI). Clinical applications of CTI and CWI may include imaging of tumor, ischemia, inflammation, cirrhosis, and other diseases. CTI can provide patient-specific models for source imaging, transcranial dc stimulation, deep brain stimulation, and electroporation.
Animal Experimentation* ; Animals* ; Anisotropy ; Brain ; Deep Brain Stimulation ; Diffusion ; Electric Conductivity ; Electrodes ; Electroporation ; Extracellular Space ; Fibrosis ; Human Body ; Inflammation ; Intracellular Space ; Ischemia ; Magnetic Resonance Imaging* ; Methods

Neurostimulation remarkably alleviates the symptoms in a variety of brain disorders by modulating the brain-wide network. However, how brain-wide effects on the direct and indirect pathways evoked by focal neurostimulation elicit therapeutic effects in an individual patient is unknown. Understanding this remains crucial for advancing neural circuit-based guidance to optimize candidate patient screening, pre-surgical target selection, and post-surgical parameter tuning. To address this issue, we propose a functional brain connectome-based modeling approach that simulates the spreading effects of stimulating different brain regions and quantifies the rectification of abnormal network topology in silico. We validated these analyses by pinpointing nuclei in the basal ganglia circuits as top-ranked targets for 43 local patients with Parkinson's disease and 90 patients from a public database. Individual connectome-based analysis demonstrated that the globus pallidus was the best choice for 21.1% and the subthalamic nucleus for 19.5% of patients. Down-regulation of functional connectivity (up to 12%) at these prioritized targets optimally maximized the therapeutic effects. Notably, the priority rank of the subthalamic nucleus significantly correlated with motor symptom severity (Unified Parkinson's Disease Rating Scale III) in the local cohort. These findings underscore the potential of neural network modeling for advancing personalized brain stimulation therapy, and warrant future experimental investigation to validate its clinical utility.
Adult ; Aged ; Brain Mapping ; Connectome ; Deep Brain Stimulation ; methods ; Female ; Humans ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Neural Pathways ; diagnostic imaging ; physiology ; Oxygen ; blood ; Parkinson Disease ; diagnostic imaging ; pathology ; therapy ; ROC Curve ; United Kingdom

Aged ; Deep Brain Stimulation ; methods ; Dystonia ; surgery ; therapy ; Female ; Globus Pallidus ; surgery ; Humans ; Magnetic Resonance Imaging ; Subthalamic Nucleus ; surgery

Objective To explore the efficacy of target positioning by preoperative CT/MRI image fusion technique in deep brain stimulation.Methods We retrospectively analyzed the clinical data and images of 79 cases (68 with Parkinson's disease, 11 with dystonia) who received preoperative CT/MRI image fusion in target positioning of subthalamic nucleus in deep brain stimulation. Deviation of implanted electrodes from the target nucleus of each patient were measured. Neurological evaluations of each patient before and after the treatment were performed and compared. Complications of the positioning and treatment were recorded.Results The mean deviations of the electrodes implanted on X, Y, and Z axis were 0.5 mm, 0.6 mm, and 0.6 mm, respectively. Postoperative neurologic evaluations scores of unified Parkinson's disease rating scale (UPDRS) for Parkinson's disease and Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) for dystonia patients improved significantly compared to the preoperative scores (P<0.001); Complications occurred in 10.1% (8/79) patients, and main side effects were dysarthria and diplopia.Conclusion Target positioning by preoperative CT/MRI image fusion technique in deep brain stimulation has high accuracy and good clinical outcomes.
Adult ; Aged ; Deep Brain Stimulation ; adverse effects ; methods ; Dystonia ; therapy ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Parkinson Disease ; therapy ; Retrospective Studies ; Tomography, X-Ray Computed

Adult ; Deep Brain Stimulation ; methods ; Female ; Humans ; Tardive Dyskinesia ; therapy