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Scalable Measurements of Intrinsic Excitability in Human iPS Cell-Derived Excitatory Neurons Using All-Optical Electrophysiology
摘要： Induced pluripotent stem (iPS) cells offer the exciting opportunity for modeling neurological disorders in vitro in the context of a human genetic background. While significant progress has been made in advancing the use of iPS cell-based disease models, there remains an unmet need to characterize the electrophysiological profile of individual neurons with sufficient throughput to enable statistically robust assessment of disease phenotypes and pharmacological modulation. Here, we describe the Optopatch platform technology that utilizes optogenetics to both stimulate and record action potentials (APs) from human iPS cell-derived excitatory neurons with similar information content to manual patch clamp electrophysiology, but with ~ 3 orders of magnitude greater throughput. Cortical excitatory neurons were produced using the NGN2 transcriptional programming approach and cultured in the presence of rodent glial cells. Characterization of the neuronal preparations using immunocytochemistry and qRT-PCR assays reveals an enrichment of neuronal and glutamatergic markers as well as select ion channels. We demonstrate the scale of our intrinsic cellular excitability assay using pharmacological assessment with select ion channel modulators quinidine and retigabine, by measuring changes in both spike timing and waveform properties. The Optopatch platform in human iPS cell-derived cortical excitatory neurons has the potential for detailed phenotype and pharmacology evaluation, which can serve as the basis of cellular disease model exploration for drug discovery and phenotypic screening efforts.
关键词： Electrophysiology,Optogenetics,Induced pluripotent stem cells
更新于2025-09-23 15:23:52
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[IEEE 2018 Conference on Design and Architectures for Signal and Image Processing (DASIP) - Porto, Portugal (2018.10.10-2018.10.12)] 2018 Conference on Design and Architectures for Signal and Image Processing (DASIP) - Real-Time Analysis of Living Biological Cell Activity
摘要： This demo shows a computing system able to process data from electrophysiology cultures in real-time. It is the first one able to identify eventual relationship among living cells from the cell activity signals. The hardware demonstrator is able to acquire data from 64 analog signals sampled at 10kHz, but the computing architecture is flexible enough to provide various number of input electrodes depending of its configuration. Most of the parameters are user definable without reconfiguration to ensure the usability of the system for real-life biology experiment.
关键词： biological cell activity,FPGA,HLS,electrophysiology,spike detection,inter-channel correlation,real-time analysis
更新于2025-09-23 15:23:52
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Reducing radiation exposure in an electrophysiology lab with introduction of newer fluoroscopic technology
摘要： The use of fluoroscopic devices exposes patients and operators to harmful effects of ionizing radiation in an electrophysiology (EP) lab. We sought to know if the newer fluoroscopic technology (Allura Clarity) installed in a hybrid EP helps to reduce prescribed radiation dose. We performed radiation dose analysis of 90 patients who underwent various procedures in the EP lab at a community teaching hospital after the introduction of newer fluoroscopic technology in June of 2016. Watchman device insertion, radiofrequency ablation procedures, pacemaker permanent (PPM)/implantable cardioverter defibrillator (ICD) placement and battery changes were included in the study to compare radiation exposure during different procedures performed commonly in an EP lab. In all cases of watchman device placement, radiofrequency ablation procedures, PPM/ICD placement and battery changes, there was a statistically significant difference (<0.05) in radiation dose exposure. Significant reduction in radiation exposure during various procedures performed in an EP lab was achieved with aid of newer fluoroscopic technology and better image detection technology.
关键词： watchman device,permanent pacemaker,Radiation exposure,insertable cardioverter defibrillator,electrophysiology lab,newer fluoroscopic system,radiofrequency ablation
更新于2025-09-23 15:22:29
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The Effect of Atropine on Human Global Flash mfERG Responses to Retinal Defocus
摘要： PURPOSE. To investigate the action of atropine on global flash multifocal electroretinogram (gmfERG) responses to retinal defocus. METHOD. gmfERG recordings were made monocularly in 19 healthy adults under three lens-imposed defocus conditions (2 diopters myopic, 2 diopters hyperopic, and no defocus) before and 24 hours after instillation of 1 drop of 0.1% atropine. Signals reflecting activity from the outer and inner retina (direct [DC] and induced [IC] components respectively) were analyzed. Responses were grouped into either a central (0°–6°) or peripheral (6°–24°) retinal zone. The gmfERG responses were compared relative to the no defocus, no atropine condition. RESULTS. Within the central zone, atropine had no effect on the amplitudes and peak times of DC or IC responses to defocus. For IC responses in the peripheral zone, there was a significant interaction effect of atropine and defocus (F2,36 = 6.050, P = 0.011) with greater post-atropine amplitudes under myopic defocus (mean increase = 15.5%, 95% confidence interval [CI] = 5.6%–25.4%, P = 0.004). Atropine also had a significant main effect of increasing IC peak times (F1,18 = 9.722, P = 0.006). For DC responses, atropine had a significant main effect of increasing DC amplitudes (F1,18 = 7.821, P = 0.012) and peak times (F1,18 = 15.406, P = 0.001) regardless of sign of defocus. CONCLUSIONS. Our results imply that atropine acts in the inner layers of the peripheral retina to affect neuronal responses to myopic defocus, raising the possibility that atropine may potentiate the effects of myopic defocus in inhibiting eye growth.
关键词： atropine,retina,hyperopic defocus,electrophysiology,myopic defocus
更新于2025-09-23 15:22:29
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Dose-dependent effect of the pulsed Nd:YAG laser in the treatment of crushed sciatic nerve in Wister rats: an experimental model
摘要： The objective of the study was to investigate the efficacy of three energy densities 4, 10, and 50 J/cm2 of pulsed Nd:YAG laser for the treatment of crushed sciatic nerve in Wister rats by evaluating changes in the sciatic functional index and the electrophysiology.A total of 180 Wistar rats were involved in the study. Rats were randomly assigned to five groups. Rats were subjected to the sciatic nerve crushing. Control negative (CONT-ve), which received no crushing; control positive (CONT+ve), which received crushing with no laser; and HILT-4, HILT-10, and HILT-50 groups, which received pulsed Nd:YAG laser (10 Hz, 360 mJ/cm2) with energy densities 4, 10, and 50 J/cm2, respectively. The SFI, the amilitude of compound motor action potential (CMAP) and sciatic motor nerve conduction velocity (MNCV) were measured before and after seven, 14, and 21 days after crushing. For the SFI and electrophysiological analysis, repeated measures ANOVA is used, followed by Bonferroni’s repeated-measures test. Statistical significance was set at p < 0.05. After one week, there was no significant difference in SFI, CMAP, and MNCV among the three laser groups with significant changes between them and CONT-ve and CONT+ve groups. There was a significant increase in either CMAP amplitude or MNCV after 14 days with significant decrease in the SFI after 21 days among all treatment groups. The pulsed Nd:YAG laser applied with energy densities 4, 10, and 50 J/cm2 significantly decreased the SFI and increased the CMAP and MNCV of the crushed sciatic nerve in Wister rats. Among laser doses, the difference in the rate of recovery in the electrophysiology was found after two weeks while in the SFI after three weeks. The improvement after the nerve injury was time and dose dependent.
关键词： Pulsed Nd:YAG laser,Crushing injury,Electrophysiology,Energy density,Sciatic functional index
更新于2025-09-23 15:19:57
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Optical Monitoring of Living Nerve Terminal Labeling in Hair Follicle Lanceolate Endings of the <em>Ex Vivo</em> Mouse Ear Skin
摘要： A novel dissection and recording technique is described for optical monitoring staining and de-staining of lanceolate terminals surrounding hair follicles in the skin of the mouse pinna. The preparation is simple and relatively fast, reliably yielding extensive regions of multiple labeled units of living nerve terminals to study uptake and release of styryl pyridinium dyes extensively used in studies of vesicle recycling. Subdividing the preparations before labeling allows test vs. control comparisons in the same ear from a single individual. Helpful tips are given for improving the quality of the preparation, the labeling and the imaging parameters. This new system is suitable for assaying pharmacologically and mechanically-induced uptake and release of these vital dyes in lanceolate terminals in both wild-type and genetically modified animals. Examples of modulatory influences on labeling intensity are given.
关键词： ear,Issue 110,Neuroscience,mechanosensation,hair follicle,electrophysiology,mouse,Lanceolate ending,skin
更新于2025-09-19 17:15:36
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Objective assessment of visual acuity: a refined model for analyzing the sweep VEP
摘要： Purpose The aim of this study was to develop a simple and reliable method for the objective assessment of visual acuity by optimizing the stimulus used in commercially available systems and by improving the methods of evaluation using a nonlinear function, the modified Ricker model. Methods Subjective visual acuity in the normal subjects was measured with Snellen targets, best-corrected, and in some cases also uncorrected and with plus lenses (+1 D, +2 D, +3 D). In patients, subjective visual acuity was measured best-corrected using the Freiburg Visual Acuity Test. Sweep VEP recordings to 11 spatial frequencies, with check sizes in logarithmically equidistant steps (0.6, 0.9, 1.4, 2.1, 3.3, 4.9, 7.3, 10.4, 18.2, 24.4, and 36.5 cpd), were obtained from 56 healthy subjects aged between 17 and 69 years (mean 42.5 ± 15.3 SD years) and 20 patients with diseases of the lens (n = 6), retina (n = 8) or optic nerve (n = 6). The results were fit by a multiple linear regression (2nd-order polynomial) or a nonlinear regression (modified Ricker model) and parameters compared (limiting spatial frequency (sflimiting) and the spatial frequency of the vertex (sfvertex) of the parabola for the 2nd-order polynomial fitting, and the maximal spatial frequency (sfmax), and the spatial frequency where the amplitude is 2 dB higher than the level of noise (sfthreshold) for the modified Ricker model. Results Recording with 11 spatial frequencies allows a more accurate determination of acuities above 1.0 logMAR. Tuning curves fitted to the results show that compared to the normal 2nd-order polynomial analysis, the modified Ricker model is able to describe closely the amplitudes of the sweep VEP in relation to the spatial frequencies of the presented checkerboards. In patients with a visual acuity better than about 0.5 (decimal), the predicted acuities based on the different parameters show a good match of the predicted visual acuities based on the models established in healthy volunteers to the subjective visual acuities. However, for lower visual acuities, both models tend to overestimate the visual acuity (up to *0.4 logMAR), especially in patients suffering from AMD. Conclusions Both models, the 2nd-order polynomial and the modified Ricker model performed equally well in the prediction of the visual acuity based on the amplitudes recorded using the sweep VEP. However, the modified Ricker model does not require the exclusion of data points from the fit, as necessary when fitting the 2nd-order polynomial model making it more reliable and robust against outliers, and, in addition, provides a measure for the noise of the recorded results.
关键词： Sweep VEP,Visual acuity,Visual electrophysiology,Visual evoked potentials
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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Variable Macropixel Spectral-Spatial Transforms With Intra- and Inter-Color Decorrelations for Arbitrary RGB CFA-Sampled Raw Images
摘要： The adult central nervous system is capable of significant reorganization and adaptation following neurotrauma. After a thoracic contusive spinal cord injury (SCI) neuropathways that innervate the cord below the epicenter of injury are damaged, with minimal prospects for functional recovery. In contrast, pathways above the site of injury remain intact and may undergo adaptive changes in response to injury. We used cortical somatosensory evoked potentials (SSEPs) to evaluate changes in intact forelimb pathways. Rats received a midline contusion SCI, unilateral contusion SCI, or laminectomy with no contusion at the T8 level and were monitored for 28 days post-injury. In the midline injury group, SSEPs recorded from the contralateral forelimb region of the primary somatosensory cortex were 59.7% (CI 34.7%, 84.8%; ) greater than the laminectomy group; SSEPs from the ipsilateral somatosensory cortex were 47.6% (CI 18.3%, 77%; ) greater. Activation of the ipsilateral somatosensory cortex was further supported by BOLD-fMRI, which showed increased oxygenation at the ipsilateral hemisphere at day seven post-injury. In the unilateral injury group, ipsilesional side was compared to the contralesional side. SSEPs on day 14 (148%; CI 111%, 185%) and day 21 (137%; CI 110%, 163%) for ipsilesional forelimb stimulation were significantly increased over baseline (100%). SSEPs recorded from the hindlimb sensory cortex upon ipsilesional stimulation were 33.9% (CI 14.3%, 53.4%; ) greater than contralesional stimulation. Therefore, these results demonstrate the ability of SSEPs to detect significant enhancements in the activation of forelimb sensory pathways following both midline and unilateral contusive SCI at T8. Reorganization of forelimb pathways may occur after thoracic SCI, which SSEPs can monitor to aid the development of future therapies.
关键词： Contusion spinal cord injury,cortical plasticity,somatosensory evoked potentials,electrophysiology,unilateral spinal cord injury
更新于2025-09-19 17:13:59
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[IEEE 2019 International Conference on Power Electronics, Control and Automation (ICPECA) - New Delhi, India (2019.11.16-2019.11.17)] 2019 International Conference on Power Electronics, Control and Automation (ICPECA) - Solar Photovoltaic Power Converters: Technologies and Their Testing Protocols for Indian Inevitabilities
摘要： The adult central nervous system is capable of significant reorganization and adaptation following neurotrauma. After a thoracic contusive spinal cord injury (SCI) neuropathways that innervate the cord below the epicenter of injury are damaged, with minimal prospects for functional recovery. In contrast, pathways above the site of injury remain intact and may undergo adaptive changes in response to injury. We used cortical somatosensory evoked potentials (SSEPs) to evaluate changes in intact forelimb pathways. Rats received a midline contusion SCI, unilateral contusion SCI, or laminectomy with no contusion at the T8 level and were monitored for 28 days post-injury. In the midline injury group, SSEPs recorded from the contralateral forelimb region of the primary somatosensory cortex were 59.7% (CI 34.7%, 84.8%; ) greater than the laminectomy group; SSEPs from the ipsilateral somatosensory cortex ) were 47.6% (CI 18.3%, 77%; greater. Activation of the ipsilateral somatosensory cortex was further supported by BOLD-fMRI, which showed increased oxygenation at the ipsilateral hemisphere at day seven post-injury. In the unilateral injury group, ipsilesional side was compared to the contralesional side. SSEPs on day 14 (148%; CI 111%, 185%) and day 21 (137%; CI 110%, 163%) for ipsilesional forelimb stimulation were significantly increased over baseline (100%). SSEPs recorded from the hindlimb sensory cortex upon ipsilesional stimulation were 33.9% (CI 14.3%, 53.4%; ) greater than contralesional stimulation. Therefore, these results demonstrate the ability of SSEPs to detect significant enhancements in the activation of forelimb sensory pathways following both midline and unilateral contusive SCI at T8. Reorganization of forelimb pathways may occur after thoracic SCI, which SSEPs can monitor to aid the development of future therapies.
关键词： somatosensory evoked potentials,electrophysiology,Contusion spinal cord injury,cortical plasticity,unilateral spinal cord injury
更新于2025-09-16 10:30:52