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- 实验方案
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Amplitude Modulation-based Electrical Stimulation for Encoding Multipixel Spatiotemporal Visual Information in Retinal Neural Activities
摘要： Retinal implants have been developed as a promising way to restore partial vision for the blind. The observation and analysis of neural activities can offer valuable insights for successful prosthetic electrical stimulation. Retinal ganglion cell (RGC) activities have been investigated to provide knowledge on the requirements for electrical stimulation, such as threshold current and the effect of stimulation waveforms. To develop a detailed 'stimulation strategy' for faithful delivery of spatiotemporal visual information to the brain, it is essential to examine both the temporal and spatial characteristics of RGC responses, whereas previous studies were mainly focused on one or the other. In this study, we investigate whether the spatiotemporal visual information can be decoded from the RGC network activity evoked by patterned electrical stimulation. Along with a thorough characterization of spatial spreading of stimulation current and temporal information encoding, we demonstrated that multipixel spatiotemporal visual information can be accurately decoded from the population activities of RGCs stimulated by amplitude-modulated pulse trains. We also found that the details of stimulation, such as pulse amplitude range and pulse rate, were crucial for accurate decoding. Overall, the results suggest that useful visual function may be restored by amplitude modulation-based retinal stimulation.
关键词： Degenerated Retina,Electrical Stimulation,Retinal Ganglion Cells,Retinal Implant,Spike Train Decoding,Microelectrode Array
更新于2025-09-23 15:22:29
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Muscle oxygenation dynamics in response to electrical stimulation as measured with near-infrared spectroscopy: A pilot study
摘要： Neuromuscular electrical stimulation (NMES) is used for preventing muscle atrophy and improving muscle strength in patients and healthy people. However, the current intensity of NMES is usually set at a level that causes the stimulated muscles to contract. This typically causes pain. Quantifying the instantaneous changes in muscle microcirculation and metabolism during NMES before muscle contraction occurs is crucial, because it enables the current intensity to be optimally tuned, thereby reducing the NMES-induced muscle pain and fatigue. We applied near-infrared spectroscopy (NIRS) to measure instantaneous and deoxygenation changes in 43 healthy young adults during NMES at 10, 15, 20, 25, 30, and 35 mA. Having been stabilized at the NIRS signal baseline, total hemoglobin concentration increased immediately after stimulation in a dose-dependent manner (p < 0.05) until stimulation was stopped at the level causing muscle contraction without pain. Tissue deoxygenation appeared relatively unchanged during NMES. We conclude that NIRS can be used to determine the optimal NMES current intensity by monitoring oxygenation changes.
关键词： Muscle oxygenation dynamics,near-infrared spectroscopy,tissue optics,neuromuscular electrical stimulation
更新于2025-09-23 15:21:21
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Electrical activation of degenerated photoreceptors in blind mouse retina elicited network-mediated responses in different types of ganglion cells
摘要： Electrical (e-) stimulation is explored in schemes to rescue the vision of blind people, e.g. those affected by Retinitis Pigmentosa (RP). We e-activated subretinally the surviving degenerated photoreceptors (d-Phrs) of the rd1 mouse (RP model) and evoked visual responses in the blind retina. The e-stimulation was applied with a single platinum/iridium electrode. The d-Phrs (calcium-imaging) and ganglion cells (GC) activity (MEA-recording) were recorded in simultaneous multilayer recordings. The findings of this study confirm that the d-Phrs responded to e-stimulation and modulated the retinal network-activity. The application of blockers revealed that the synaptic interactions were dependent on voltage-gated calcium channels and mediated by the transmitters glutamate and GABA. Moreover, the gap junctions coupled networks promoted the lateral-spread of the e-evoked activity in the outer (~60 μm) and inner (~120 μm) retina. The activated GCs were identified as subtypes of the ON, OFF and ON-OFF classes. In conclusion, d-Phrs are the ideal interface partners for implants to elicit enhanced visual responses at higher temporal and spatial resolution. Furthermore, the retina’s intact circuity at the onset of complete blindness makes it a tempting target when considering the implantation of implants into young patients to provide a seamless transition from blinding to chip-aided vision.
关键词： blind retina,MEA recording,subretinal implant,gap junctions,glutamate,rd1 mouse,calcium imaging,ganglion cells,GABA,electrical stimulation,Retinitis Pigmentosa,degenerated photoreceptors
更新于2025-09-19 17:15:36
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Retinotopic Responses in the Visual Cortex Elicited by Epiretinal Electrical Stimulation in Normal and Retinal Degenerate Rats
摘要： Electronic retinal prostheses restore vision in people with outer retinal degeneration by electrically stimulating the inner retina. We characterized visual cortex electrophysiologic response elicited by electrical stimulation of retina in normally sighted and retinal degenerate rats. rats were used to map cortical responses elicited by epiretinal electrical stimulation in four quadrants of the retina. Six normal and six rd rats were used to compare the dendritic spine density of neurons in the visual cortex. Results: The rd rats required higher stimulus amplitudes to elicit responses in the visual cortex. The cortical electrically evoked responses (EERs) for both healthy and rd rats show a dose-response characteristic with respect to the stimulus amplitude. The EER maps in healthy rats show retinotopic organization. For rd rats, cortical retinotopy is not well preserved. The neurons in the visual cortex of rd rats show a 10% higher dendritic spine density than in the healthy rats. Conclusions: Cortical activity maps, produced when epiretinal stimulation is applied to quadrants of the retina, exhibit retinotopy in normal but not rd rats. This is likely due to a combination of degeneration of the retina and increased stimulus thresholds in rd, which broadens the activated area of the retina. Translational Relevance: Loss of retinotopy is evident in rd rats. If a similar loss of retinotopy is present in humans, retinal prostheses design must include flexibility to account for patient specific variability.
关键词： cortical electrophysiology,retinitis pigmentosa,retinotopy,electrical stimulation,rat
更新于2025-09-19 17:15:36
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Visual prostheses: The enabling technology to give sight to the blind
摘要： Millions of patients are either slowly losing their vision or are already blind due to retinal degenerative diseases such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD) or because of accidents or injuries. Employment of artificial means to treat extreme vision impairment has come closer to reality during the past few decades. Currently, many research groups work towards effective solutions to restore a rudimentary sense of vision to the blind. Aside from the efforts being put on replacing damaged parts of the retina by engineered living tissues or microfabricated photoreceptor arrays, implantable electronic microsystems, referred to as visual prostheses, are also sought as promising solutions to restore vision. From a functional point of view, visual prostheses receive image information from the outside world and deliver them to the natural visual system, enabling the subject to receive a meaningful perception of the image. This paper provides an overview of technical design aspects and clinical test results of visual prostheses, highlights past and recent progress in realizing chronic high-resolution visual implants as well as some technical challenges confronted when trying to enhance the functional quality of such devices.
关键词： Medical Implants,Electrical Stimulation,Visual Prostheses,Neural Prostheses
更新于2025-09-19 17:15:36
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[IEEE 2019 International Conference on Optical MEMS and Nanophotonics (OMN) - Daejeon, Korea (South) (2019.7.28-2019.8.1)] 2019 International Conference on Optical MEMS and Nanophotonics (OMN) - Electromagnetic FPCB micromirror scanning laser rangefinder
摘要： Since several years, the number of total hip arthroplasty revision surgeries is substantially growing. One of the main reasons for this procedure to become necessary is the loosening or damage of the prothesis, which is facilitated by bone necrosis at the implant–bone interface. Electrostimulation is one promising technique, which can accelerate the growth of bone cells and, therefore, enhance the anchorage of the implant to the bone. We present computational models of an electrostimulative total hip revision system to enhance bone regeneration. In this study, the influence of uncertainty in the conductivity of bone tissue on the electric field strength and the beneficial stimulation volume for an optimized electrode geometry and arrangement is investigated. The generalized polynomial chaos technique is used to quantify the uncertainty in the stimulation volumes with respect to the uncertain conductivity of cancellous bone, bone marrow, and bone substitute, which is used to fill defective areas. The results suggest that the overall beneficial stimulation areas are only slightly sensitive to the uncertainty in conductivity of bone tissue. However, in the proximity of tissue boundaries, larger uncertainties, especially in the transition between beneficial and understimulation areas, can be expected.
关键词： Electrical stimulation,finite-element method,multiobjective optimization,uncertainty quantification,total hip arthroplasty (THA) revision
更新于2025-09-19 17:13:59
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Scattering Effect on Optical Performance of Quantum Dot White Light-Emitting Diodes Incorporating SiOa?? Nanoparticles
摘要： Traditional rehabilitation techniques have limited effects on the recovery of patients with tetraplegia. A brain–computer interface (BCI) provides an interactive channel that does not depend on the normal output of peripheral nerves and muscles. In this paper, an integrated framework of a noninvasive electroencephalogram (EEG)-based BCI with a noninvasive functional electrical stimulation (FES) is established, which can potentially enable the upper limbs to achieve more effective motor rehabilitation. The EEG signals based on steady-state visual evoked potential are used in the BCI. Their frequency domain characteristics identi?ed by the pattern recognition method are utilized to recognize intentions of ?ve subjects with average accuracy of 73.9%. Furthermore the movement intentions are transformed into instructions to trigger FES, which is controlled with iterative learning control method, to stimulate the relevant muscles of upper limbs tracking desired velocity and position. It is a useful technology with potential to restore, reinforce or replace lost motor function of patients with neurological injuries. Experiments with ?ve healthy subjects demonstrate the feasibility of BCI integrated with upper extremity FES toward improved function restoration for an individual with upper limb disabilities, especially for patients with tetraplegia.
关键词： rehabilitation robotics,functional electrical stimulation,human–robot interaction,intelligent control,Brain–computer interfaces
更新于2025-09-19 17:13:59
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[IEEE 2019 21st International Middle East Power Systems Conference (MEPCON) - Cairo, Egypt (2019.12.17-2019.12.19)] 2019 21st International Middle East Power Systems Conference (MEPCON) - Optimal Allocation of Reactive Power Compensation in a Distribution Network with Photovoltaic System Integration
摘要： Since several years, the number of total hip arthroplasty revision surgeries is substantially growing. One of the main reasons for this procedure to become necessary is the loosening or damage of the prothesis, which is facilitated by bone necrosis at the implant–bone interface. Electrostimulation is one promising technique, which can accelerate the growth of bone cells and, therefore, enhance the anchorage of the implant to the bone. We present computational models of an electrostimulative total hip revision system to enhance bone regeneration. In this study, the influence of uncertainty in the conductivity of bone tissue on the electric field strength and the beneficial stimulation volume for an optimized electrode geometry and arrangement is investigated. The generalized polynomial chaos technique is used to quantify the uncertainty in the stimulation volumes with respect to the uncertain conductivity of cancellous bone, bone marrow, and bone substitute, which is used to fill defective areas. The results suggest that the overall beneficial stimulation areas are only slightly sensitive to the uncertainty in conductivity of bone tissue. However, in the proximity of tissue boundaries, larger uncertainties, especially in the transition between beneficial and understimulation areas, can be expected.
关键词： Electrical stimulation,finite-element method,multiobjective optimization,uncertainty quantification,total hip arthroplasty (THA) revision
更新于2025-09-19 17:13:59
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[IEEE 2018 EMF-Med 1st World Conference on Biomedical Applications of Electromagnetic Fields (EMF-Med) - Split, Croatia (2018.9.10-2018.9.13)] 2018 EMF-Med 1st World Conference on Biomedical Applications of Electromagnetic Fields (EMF-Med) - Electrical stimulation increases schwann cells proliferation inside hyaluronic acid conduits
摘要： After nerve injury in the peripheral nervous system (PNS), application of an appropriate electrical stimulation (ES) may increase the rate and success of nerve repair. Tubular structures to mimic nervous tracts have been conducted with promising results. Schwann cells (SCs) are the main supportive cells of neurons in the PNS. In this work, we used hyaluronic acid (HA) tubular scaffolds with SCs and applied two different current intensities (450 μA and 900 μA) in order to study their effects on cells behaviour. Our data showed a beneficial effect of ES on cell number when applying a current of 450 μA. The application of tissue engineering and ES may accelerate and increase functional recovery in the PNS.
关键词： hyaluronic acid,poly-lactic fibers,electrical stimulation,nerve guidance conduit,neural differentiation
更新于2025-09-10 09:29:36
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Intraoperative Thermography of the Electrical Stimulation Mapping: A Safety Control Study
摘要： A standard procedure for continuous intraoperative monitoring of the integrity of the corticospinal tracts by eliciting muscle responses is the electric stimulation mapping (ESM). However, standard ESM protocols are ineffective in 20% of young children. We have developed a novel, highly efficient paradigm consisting of short-time burst (30 ms) of high frequency (500 Hz) and high peak current (≤100 mA), which may cause local tissue overheating. The presented safety control study was therefore designed. The infrared thermography camera captured to-be-resected cortex of 13 patients in vivo during ESM. Thermograms were image processed to reveal discrete ESM thermal effect of currents from 10 to 100 mA. Peak 100 mA currents induced a maximal increase in temperature of 3.1 °C, 1.23 ± 0.72 °C in average. The warming correlated with stimulating electrode resistance (p < 0.001). The measurement uncertainty was estimated ±1.01 °C for the most skeptical conditions. The histopathological evaluation of stimulated tissue (performed in all cases) did not show any destructive changes. Our study demonstrates the ability of the thermographic camera to measure the discrete thermal effect of the ESM. The results provide evidence for the safety of the proposed protocol for full range currents with minimal risk of brain tissue damage.
关键词： neurosurgery,safety control,Electrical stimulation mapping,thermography,thermal effect,in vivo
更新于2025-09-09 09:28:46