Deep learning for automated detection of neovascular leakage on ultra-widefield fluorescein angiography in diabetic retinopathy.

Diabetic retinopathy is a leading cause of blindness in working-age adults worldwide. Neovascular leakage on fluorescein angiography indicates progression to the proliferative stage of diabetic retinopathy, which is an important distinction that requires timely ophthalmic intervention with laser or intravitreal injection treatment to reduce the risk of severe, permanent vision loss. In this study, we developed a deep learning algorithm to detect neovascular leakage on ultra-widefield fluorescein angiography images obtained from patients with diabetic retinopathy. The algorithm, an ensemble of three convolutional neural networks, was able to accurately classify neovascular leakage and distinguish this disease marker from other angiographic disease features. With additional real-world validation and testing, our algorithm could facilitate identification of neovascular leakage in the clinical setting, allowing timely intervention to reduce the burden of blinding diabetic eye disease.

Retinal neovascularization as self-organized criticality on ultra-widefield fluorescein angiography imaging of diabetic retinopathy.

BACKGROUND/OBJECTIVES: Do the distributions of surface area of non-perfusion (NP) and neovascularization (NV) on ultra-widefield fluorescein angiography (UWF FA) in patients with diabetic retinopathy (DR) differ significantly? SUBJECTS/METHODS: Inclusion criteria were patients who had a UWF FA taken for DR at the Kellogg Eye Center from January 2009 to May 2018. Exclusion criteria included previous panretinal photocoagulation and significant media opacity (e.g., vitreous haemorrhage or significant cataract). UWF FAs were manually segmented for surface areas of NP and NV. The total areas per patient were organized in a histogram, and logarithmically binned to test against power law and exponential distributions. Then, a computational model was constructed in Python 3.7 to suggest a mechanistic explanation for the observed distributions. RESULTS: Analysis of areas of NV across 189 images demonstrated a superior fit by the least squares method to a power law distribution (p = 0.014) with an R2 fit of 0.9672. Areas of NP over 794 images demonstrated a superior fit with an exponential distribution instead (p = 0.011). When the far periphery was excluded, the R2 fit for the exponential distribution was 0.9618. A computational model following the principles of self-organized criticality (SOC), akin to earthquake and forest fire models, matched these datasets. CONCLUSIONS: These distributions inform what useful statistics may be applied to study of these imaging characteristics. Further, the difference in event distribution between NV and NP suggests that the two phenomena are mechanistically distinct. NV may follow SOC, propagating as a catastrophic event in an unpredictable manner.

Aflibercept more effectively weans patients with neovascular age-related macular degeneration off therapy compared with bevacizumab.

BACKGROUNDStudies assessing the efficacy of therapies for neovascular age-related macular degeneration (nvAMD) have demonstrated that aflibercept may have a longer treatment interval than its less-expensive alternative, bevacizumab. However, whether this benefit justifies the additional cost of aflibercept remains under debate. We have recently reported that a treat-and-extend-pause/monitor approach can be used to successfully wean 31% of patients with nvAMD off anti-VEGF therapy. Here, we examined whether the choice of therapy influences the outcomes of this approach.METHODSIn this retrospective analysis, 122 eyes of 106 patients with nvAMD underwent 3 consecutive monthly injections with either aflibercept (n = 70) or bevacizumab (n = 52), followed by a treat-and-extend protocol, in which the decision to extend the interval between treatments was based on visual acuity, clinical exam, and the presence or absence of fluid on optical coherence tomography. Eyes that remained stable 12 weeks from their prior treatment were given a 6-week trial of holding further treatment, followed by quarterly monitoring. Treatment was resumed for worsening vision, clinical exam, or optical coherence tomography findings.RESULTSAt the end of 1 year, eyes receiving bevacizumab had similar vision but required more injections (8.7 ± 0.3 treatments vs. 7.2 ± 0.3 treatments) compared with eyes receiving aflibercept. However, eyes treated with aflibercept were almost 3 times more likely to be weaned off treatment (43% vs. 15%) compared with eyes treated with bevacizumab at the end of 1 year.CONCLUSIONThese observations expose an advantage of aflibercept over bevacizumab and have important clinical implications for the selection of therapy for patients with nvAMD.FUNDINGThis work was supported by the National Eye Institute, NIH grants R01EY029750 and R01EY025705, Research to Prevent Blindness, the Alcon Young Investigator Award from the Alcon Research Institute, and the Branna and Irving Sisenwein Professorship in Ophthalmology.

Spatial Characteristics of Peripheral Visual Islands in Retinitis Pigmentosa.

Purpose: Retinitis pigmentosa (RP) is typified by progressive peripheral visual field (pVF) loss in patterns that can vary between individuals. Greater understanding of pVF preservation may inform research on therapeutic targets. However, characteristics of retained pVF are incompletely understood. We aimed to evaluate the spatial characteristics of retained pVF in RP. Methods: We developed a computational platform to generate a probability map of the spatial distribution of retained pVF loci using the Goldmann V4e isopter. RP subjects were grouped into cross-sectional and longitudinal datasets. Probability maps of retained pVF were generated for categories of symptomatic disease duration (SDD). We applied a mathematical model to determine the anatomical correlate of the retained pVF. Results: A total of 152 subjects were included. The mean age was 46.7 years. SDD was <20 years (47.4%), 20 to 40 years (39.5%), or >40 years (13.2%). Longitudinal data (3.2-5.7 years of follow up) were available for 65 subjects. In the cross-sectional dataset, retained pVF loci were most likely to be located between the 50° and 80° isoeccentric meridians and between the 30° to 50° radial axes. In the longitudinal dataset, inferotemporal pVF loci were the most likely to be preserved over time. The area of pVF retention corresponded anatomically to the pre-equatorial superonasal retina. Conclusions: Semiautomated quantitation of pVF may be a useful tool to analyze spatial characteristics of VF in RP. Retinal cells in the superonasal periphery may be resilient to RP-related functional decline. Understanding the cellular and molecular basis of pVF resilience in the retina may inform efforts to develop treatment modalities for RP.

Aqueous proteins help predict the response of patients with neovascular age-related macular degeneration to anti-VEGF therapy.

BackgroundTo reduce the treatment burden for patients with neovascular age-related macular degeneration (nvAMD), emerging therapies targeting vascular endothelial growth factor (VEGF) are being designed to extend the interval between treatments, thereby minimizing the number of intraocular injections. However, which patients will benefit from longer-acting agents is not clear.MethodsEyes with nvAMD (n = 122) underwent 3 consecutive monthly injections with currently available anti-VEGF therapies, followed by a treat-and-extend protocol. Patients who remained quiescent 12 weeks from their prior treatment entered a treatment pause and were switched to pro re nata (PRN) treatment (based on vision, clinical exam, and/or imaging studies). Proteomic analysis was performed on aqueous fluid to identify proteins that correlate with patients' response to treatment.ResultsAt the end of 1 year, 38 of 122 eyes (31%) entered a treatment pause (≥30 weeks). Conversely, 21 of 122 eyes (17%) failed extension and required monthly treatment at the end of year 1. Proteomic analysis of aqueous fluid identified proteins that correlated with patients' response to treatment, including proteins previously implicated in AMD pathogenesis. Interestingly, apolipoprotein-B100 (ApoB100), a principal component of drusen implicated in the progression of nonneovascular AMD, was increased in treated patients who required less frequent injections. ApoB100 expression was higher in AMD eyes compared with controls but was lower in eyes that develop choroidal neovascularization (CNV), consistent with a protective role. Accordingly, mice overexpressing ApoB100 were partially protected from laser-induced CNV.FundingThis work was supported by the National Eye Institute, National Institutes of Health grants R01EY029750, R01EY025705, and R01 EY27961; the Research to Prevent Blindness, Inc.; the Alcon Research Institute; and Johns Hopkins University through the Robert Bond Welch and Branna and Irving Sisenwein professorships in ophthalmology.ConclusionAqueous biomarkers could help identify patients with nvAMD who may not require or benefit from long-term treatment with anti-VEGF therapy.

Frequency of Urgent or Emergent Vitreoretinal Surgical Procedures in the United States During the COVID-19 Pandemic.

Importance: The American Academy of Ophthalmology (AAO) indicated that urgent or emergent vitreoretinal surgical procedures should continue during the coronavirus disease 2019 (COVID-19) pandemic. Although decreases in the frequency of critical procedures have been reported outside the field of ophthalmology, analyses are limited by volume, geography, and time. Objective: To evaluate whether the frequency of ophthalmic surgical procedures deemed urgent or emergent by the AAO changed across the United States during the COVID-19 pandemic. Design, Setting, and Participants: Vitreoretinal practices from 17 institutions throughout the US participated in this multicenter cross-sectional study. The frequency of 11 billed vitreoretinal Current Procedural Terminology (CPT) codes across respective weeks was obtained from each practice between January 1, 2019, and May 31, 2020. Data were clustered into intravitreal injections (code 67028), lasers and cryotherapy (codes 67141, 67145, and 67228), retinal detachment (RD) repairs (codes 67107, 67108, 67110, and 67113), and other vitrectomies (codes 67036, 67039, and 67040). Institutions were categorized by region (Northeast, Midwest, South, and West Coast), practice setting (academic [tax-exempt] or private [non-tax-exempt]), and date of respective statewide stay-at-home orders. Main Outcomes and Measures: Nationwide changes in the frequency of billing for urgent or emergent vitreoretinal surgical procedures during the COVID-19 pandemic. Results: A total of 526 536 CPT codes were ascertained: 483 313 injections, 19 257 lasers or cryotherapy, 14 949 RD repairs, and 9017 other vitrectomies. Relative to 2019, a weekly institutional decrease in injections was observed from March 30 to May 2, 2020, with a maximal 38.6% decrease (from a mean [SD] of 437.8 [436.3] to 273.8 [269.0] injections) from April 6 to 12, 2020 (95% CI, -259 to -69 injections; P = .002). A weekly decrease was also identified that spanned a longer interval, at least until study conclusion (March 16 to May 31, 2020), for lasers and cryotherapy, with a maximal 79.6% decrease (from a mean [SD] of 6.6 [7.7] to 1.5 [2.0] procedures) from April 6 to 12, 2020 (95% CI, -6.8 to -3.3 procedures; P < .001), for RD repairs, with a maximal 59.4% decrease (from a mean [SD] of 3.5 [4.0] to 1.6 [2.2] repairs) from April 13 to 19, 2020 (95% CI, -2.7 to -1.4 repairs; P < .001), and for other vitrectomies, with a maximal 84.3% decrease (from a mean [SD] of 3.0 [3.1] to 0.4 [0.8] other vitrectomies) from April 6 to 12, 2020 (95% CI, -3.3 to -1.8 other vitrectomies; P < .001). No differences were identified by region, setting, or state-level stay-at-home order adjustment. Conclusions and Relevance: Although the AAO endorsed the continued performance of urgent or emergent vitreoretinal surgical procedures, the frequency of such procedures throughout the country experienced a substantial decrease that may persist after the COVID-19 pandemic's initial exponential growth phase. This decrease appears independent of region, setting, and state-level stay-at-home orders. It is unknown to what extent vitreoretinal intervention would have decreased without AAO recommendations, and how the decrease is associated with outcomes. Although safety is paramount during the COVID-19 pandemic, practices should consider prioritizing availability for managing high-acuity conditions until underlying reasons for the reduction are fully appreciated.

Splenial Restricted Diffusion as MRI Correlate of Diaschisis in a Blind Infant With Unilateral Posterior Cerebral Artery Stroke.

ABSTRACT: A 3-month-old male infant appeared on multiple clinical examinations to have acutely developed bilateral retrogeniculate blindness. Electroencephalography showed focal status epilepticus confined to the left posterior cerebral hemisphere. MRI demonstrated restricted diffusion in the domain of the left posterior cerebral artery consistent with acute stroke. Notably, the restricted diffusion extended across the midline in the splenium of the corpus callosum. This splenial sign may be the imaging correlate of cerebral diaschisis, a well-described phenomenon in which patients with new brain lesions develop acutely impaired neurologic function in related but nonlesioned brain regions. Diaschisis has been posited as the explanation for the temporary bilateral blindness in adult patients suffering from unilateral occipital infarctions.

Antimicrobial guide to posterior segment infections.

PURPOSE: This review article is meant to serve as a reference guide and to assist the treating physician in making an appropriate selection and duration of an antimicrobial agent. METHODS: Literature review. RESULTS: Infections of the posterior segment require prompt medical or surgical therapy to reduce the risk of permanent vision loss. While numerous options exist to treat these infections, doses and alternative therapies, especially with contraindications for first-line therapy, are often elusive. Antimicrobial agents to treat posterior segment infections can be administered via various routes, including topical, intravitreal, intravenous, and oral. CONCLUSIONS: Although there are many excellent review articles on the management of endophthalmitis, we take the opportunity in this review to comprehensively summarize the appropriate antimicrobial regimen of both common and rare infectious etiologies of the posterior segment, using evidence from clinical trials and large case series.

Quantification of Retinal Nonperfusion and Neovascularization With Ultrawidefield Fluorescein Angiography in Patients With Diabetes and Associated Characteristics of Advanced Disease.

Importance: Quantification of nonperfusion (NP) and neovascularization (NV) in diabetic retinopathy (DR) may identify better biomarkers of disease progression. Objective: To identify demographic risk factors and markers of advanced DR that are associated with increased areas of NP and NV in eyes with disease ranging from no DR but diagnosed as having diabetes to proliferative DR (PDR) and to calculate a threshold total area of NP that may be associated with an increased risk of PDR. Design, Setting, and Participants: This retrospective case series was performed on ultrawidefield fluorescein angiography (UWF FA) images from January 2009 to May 2018 at the University of Michigan Kellogg Eye Center. A total of 363 participants (651 eyes) diagnosed as having type 1 or 2 diabetes receiving UWF FA were included. Exclusion criteria included previous panretinal photocoagulation (PRP) and poor-quality images (eg, vitreous hemorrhage and significant cataract). Main Outcomes and Measures: The surface areas in millimeters squared of the foveal avascular zone; total NP; NP at posterior pole, midperiphery, and far periphery; total NV; NV at posterior pole, midperiphery, and far periphery were measured. Results: Of 363 patients, most were male (205 patients [56.5%]) and white (247 [68%]) or black (77 [21.2%]). The mean (SD) age was 59.4 (13.7) years. Seventy-six eyes with no DR, 92 with mild NPDR, 144 with moderate NPDR, 101 with severe NPDR, 220 with PDR, and 18 with DR of unknown severity were included. Male sex had a positive association with total NP (difference, 15.72; 95% CI, 4.83-26.61; P = .005); black race/ethnicity with total NV (difference, 2.32; 95% CI, 0.09-4.55; P = .04); and vitreous hemorrhage with total NP (difference, 30.00; 95% CI, 5.26-54.75; P = .02). A threshold total NP area of 77.48 mm2 (95% CI, 54.24-92.66 mm2) was identified, at greater than which patients may have an increased risk of developing PDR (sensitivity of 59.5% and specificity of 73.6%). Conclusions and Relevance: Our results indicate NP and NV can be quantified on UWF FA. These biomarkers interpreted with demographic risk factors may help predict disease progression. Conclusions are limited by ascertainment and information biases because the results are from retrospective data.

Algorithm Variability in Quantification of Epithelial Defect Size in Microbial Keratitis Images.

PURPOSE: To investigate the sources of measurement variability when quantifying the morphology of microbial keratitis (MK) from slit-lamp photography (SLP) images using a semiautomated, image-analysis algorithm. METHODS: Prospectively enrolled patients with MK underwent SLP to obtain images of their epithelial defects (ED). Eyes were stained with fluorescein and imaged multiple times under blue light, at low and high magnifications. A masked research assistant chose the 3 best images and annotated each 3 times to provide seed regions corresponding to ED and healthy cornea. The algorithm returned the ED area for each seeded image. Eyes without EDs and algorithm failures were excluded. Variance components were estimated with a random effects model and intraclass correlation coefficients estimated with intragrader reliability. RESULTS: A total of 42 eyes from 42 MK participants were photographed. After excluding poor quality images, eyes with no EDs, and algorithm failures, 34 patients with 92 images and 274 seeds were analyzed. No significant differences in the average ED area were found between seedings or high- versus low-SLP magnifications (all P > 0.5, paired t tests). Minimal measurement variability was because of image (0.9%), magnification (0.2%), or seed (0.1%). Most variability was attributable to differences in ED sizes between patients (85.2%). 13.7% of variability was unexplained. Multiple iterations of the algorithm on the same image showed good consistency (intraclass correlation coefficient = 0.98, 95% confidence interval, 0.97-0.99). CONCLUSIONS: Image-analysis algorithms showed good reliability for measuring the ED area from SLP images. Most measurement variability was because of between-patient differences, not imaging settings or application of the algorithm by the user.

Optical Coherence Tomography Angiography Imaging in Inherited Retinal Diseases.

Optical coherence tomography angiography (OCTA) is a novel, noninvasive imaging modality that allows depth-resolved imaging of the microvasculature in the retina and the choroid. It is a powerful research tool to study the pathobiology of retinal diseases, including inherited retinal dystrophies. In this review, we provide an overview of the evolution of OCTA technology, compare the specifications of various OCTA devices, and summarize key findings from published OCTA studies in inherited retinal dystrophies including retinitis pigmentosa, Stargardt disease, Best vitelliform macular dystrophy, and choroideremia. OCTA imaging has provided new data on characteristics of these conditions and has contributed to a deeper understanding of inherited retinal disease.

Smartphone-based fundus photography for screening of plus-disease retinopathy of prematurity.

BACKGROUND: Inadequate screening of treatment-warranted retinopathy of prematurity (ROP) can lead to devastating visual outcomes. Especially in resource-poor communities, the use of an affordable, portable, and easy to use smartphone-based non-contact fundus photography device may prove useful for screening for high-risk ROP. This study evaluates the feasibility of screening for high-risk ROP using a novel smartphone-based fundus photography device, RetinaScope. METHODS: Retinal images were obtained using RetinaScope on a cohort of prematurely born infants during routine examinations for ROP. Images were reviewed by two masked graders who determined the image quality, the presence or absence of plus disease, and whether there was retinopathy that met predefined criteria for referral. The agreement between image-based assessments was compared to the gold standard indirect ophthalmoscopic assessment. RESULTS: Fifty-four eyes of 27 infants were included. A wide-field fundus photograph was obtained using RetinaScope. Image quality was acceptable or excellent in 98% and 95% of cases. There was substantial agreement between the gold standard and photographic assessment of presence or absence of plus disease (Cohen's κ = 0.85). Intergrader agreement on the presence of any retinopathy in photographs was also high (κ = 0.92). CONCLUSIONS: RetinaScope can capture digital retinal photographs of prematurely born infants with good image quality for grading of plus disease.

Smartphone-Based, Rapid, Wide-Field Fundus Photography for Diagnosis of Pediatric Retinal Diseases.

PURPOSE: An important, unmet clinical need is for cost-effective, reliable, easy-to-use, and portable retinal photography to evaluate preventable causes of vision loss in children. This study presents the feasibility of a novel smartphone-based retinal imaging device tailored to imaging the pediatric fundus. METHODS: Several modifications for children were made to our previous device, including a child-friendly 3D printed housing of animals, attention-grabbing targets, enhanced image stitching, and video-recording capabilities. Retinal photographs were obtained in children undergoing routine dilated eye examination. Experienced masked retina-specialist graders determined photograph quality and made diagnoses based on the images, which were compared to the treating clinician's diagnosis. RESULTS: Dilated fundus photographs were acquired in 43 patients with a mean age of 6.7 years. The diagnoses included retinoblastoma, Coats' disease, commotio retinae, and optic nerve hypoplasia, among others. Mean time to acquire five standard photographs totaling 90-degree field of vision was 2.3 ± 1.1 minutes. Patients rated their experience of image acquisition favorably, with a Likert score of 4.6 ± 0.8 out of 5. There was 96% agreement between image-based diagnosis and the treating clinician's diagnosis. CONCLUSIONS: We report a handheld smartphone-based device with modifications tailored for wide-field fundus photography in pediatric patients that can rapidly acquire fundus photos while being well-tolerated. TRANSLATIONAL RELEVANCE: Advances in handheld smartphone-based fundus photography devices decrease the technical barrier for image acquisition in children and may potentially increase access to ophthalmic care in communities with limited resources.

Novel Image-Based Analysis for Reduction of Clinician-Dependent Variability in Measurement of the Corneal Ulcer Size.

PURPOSE: To assess variability in corneal ulcer measurements between ophthalmologists and reduce clinician-dependent variability using semiautomated segmentation of the ulcer from photographs. METHODS: Three ophthalmologists measured 50 patients' eyes for epithelial defects (EDs) and the stromal infiltrate (SI) size using slit-lamp (SL) calipers. SL photographs were obtained. An algorithm was developed for semiautomatic segmenting of the ED and SI in the photographs. Semiautomatic segmentation was repeated 3 times by different users (2 ophthalmologists and 1 trainee). Clinically significant variability was assessed with intraclass correlation coefficients (ICCs) and the percentage of pairwise measurements differing by ≥0.5 mm. Semiautomatic segmentation measurements were compared with manual delineation of the image by a corneal specialist (gold standard) using Dice similarity coefficients. RESULTS: Ophthalmologists' reliability in measurements by SL calipers had an ICC from 0.84 to 0.88 between examiners. Measurements by semiautomatic segmentation had an ICC from 0.96 to 0.98. SL measures of ulcers by clinical versus semiautomatic segmentation measures differed by ≥0.5 mm in 24% to 38% versus 8% to 28% (ED height); 30% to 52% versus 12% to 34% (ED width); 26% to 38% versus 10% to 32% (SI height); and 38% to 58% versus 14% to 34% (SI width), respectively. Average Dice similarity coefficients between manual and repeated semiautomatic segmentation ranged from 0.83 to 0.86 for the ED and 0.78 to 0.83 for the SI. CONCLUSIONS: Variability exists when measuring corneal ulcers, even among ophthalmologists. Photography and computerized methods for quantifying the ulcer size could reduce variability while remaining accurate and impact quantitative measurement endpoints.

Optic Nerve Avulsion After Finger-Poke Injury.

We present a case of optic nerve avulsion as a result of finger-poke injury to the eye. Spectral domain optical coherence tomography demonstrated a plunging cup indicative of the avulsion, a finding not previously described. Optic nerve avulsion is a form of anterior indirect traumatic optic neuropathy evoked by a sudden severe rotation at the junction of the optic nerve and globe induced, in this case, by penetration of the finger into the nasal orbit.

Isolated Primary Blast Inhibits Long-Term Potentiation in Organotypic Hippocampal Slice Cultures.

Over the last 13 years, traumatic brain injury (TBI) has affected over 230,000 U.S. service members through the conflicts in Iraq and Afghanistan, mostly as a result of exposure to blast events. Blast-induced TBI (bTBI) is multi-phasic, with the penetrating and inertia-driven phases having been extensively studied. The effects of primary blast injury, caused by the shockwave interacting with the brain, remain unclear. Earlier in vivo studies in mice and rats have reported mixed results for primary blast effects on behavior and memory. Using a previously developed shock tube and in vitro sample receiver, we investigated the effect of isolated primary blast on the electrophysiological function of rat organotypic hippocampal slice cultures (OHSC). We found that pure primary blast exposure inhibited long-term potentiation (LTP), the electrophysiological correlate of memory, with a threshold between 9 and 39 kPa·ms impulse. This deficit occurred well below a previously identified threshold for cell death (184 kPa·ms), supporting our previously published finding that primary blast can cause changes in brain function in the absence of cell death. Other functional measures such as spontaneous activity, network synchronization, stimulus-response curves, and paired-pulse ratios (PPRs) were less affected by primary blast exposure, as compared with LTP. This is the first study to identify a tissue-level tolerance threshold for electrophysiological changes in neuronal function to isolated primary blast.

Automated quantification of neuronal networks and single-cell calcium dynamics using calcium imaging.

BACKGROUND: Recent advances in genetically engineered calcium and membrane potential indicators provide the potential to estimate the activation dynamics of individual neurons within larger, mesoscale networks (100s-1000+neurons). However, a fully integrated automated workflow for the analysis and visualization of neural microcircuits from high speed fluorescence imaging data is lacking. NEW METHOD: Here we introduce FluoroSNNAP, Fluorescence Single Neuron and Network Analysis Package. FluoroSNNAP is an open-source, interactive software developed in MATLAB for automated quantification of numerous biologically relevant features of both the calcium dynamics of single-cells and network activity patterns. FluoroSNNAP integrates and improves upon existing tools for spike detection, synchronization analysis, and inference of functional connectivity, making it most useful to experimentalists with little or no programming knowledge. RESULTS: We apply FluoroSNNAP to characterize the activity patterns of neuronal microcircuits undergoing developmental maturation in vitro. Separately, we highlight the utility of single-cell analysis for phenotyping a mixed population of neurons expressing a human mutant variant of the microtubule associated protein tau and wild-type tau. COMPARISON WITH EXISTING METHOD(S): We show the performance of semi-automated cell segmentation using spatiotemporal independent component analysis and significant improvement in detecting calcium transients using a template-based algorithm in comparison to peak-based or wavelet-based detection methods. Our software further enables automated analysis of microcircuits, which is an improvement over existing methods. CONCLUSIONS: We expect the dissemination of this software will facilitate a comprehensive analysis of neuronal networks, promoting the rapid interrogation of circuits in health and disease.

Alterations in Hippocampal Network Activity after In Vitro Traumatic Brain Injury.

Traumatic brain injury (TBI) alters function and behavior, which can be characterized by changes in electrophysiological function in vitro. A common cognitive deficit after mild-to-moderate TBI is disruption of persistent working memory, of which the in vitro correlate is long-lasting, neuronal network synchronization that can be induced pharmacologically by the gamma-aminobutyric acid A antagonist, bicuculline. We utilized a novel in vitro platform for TBI research, the stretchable microelectrode array (SMEA), to investigate the effects of TBI on bicuculline-induced, long-lasting network synchronization in the hippocampus. Mechanical stimulation significantly disrupted bicuculline-induced, long-lasting network synchronization 24 h after injury, despite the continued ability of the injured neurons to fire, as revealed by a significant increase in the normalized spontaneous event rate in the dentate gyrus (DG) and CA1. A second challenge with bicuculline 24 h after the first challenge significantly decreased the normalized spontaneous event rate in the DG. In addition, we illustrate the utility of the SMEA for TBI research by combining multiple experimental paradigms in one platform, which has the potential to enable novel investigations into the mechanisms responsible for functional consequences of TBI and speed the rate of drug discovery.

An open-source toolbox for automated phenotyping of mice in behavioral tasks.

Classifying behavior patterns in mouse models of neurological, psychiatric and neurodevelopmental disorders is critical for understanding disease causality and treatment. However, complete characterization of behavior is time-intensive, prone to subjective scoring, and often requires specialized equipment. Although several reports describe automated home-cage monitoring and individual task scoring methods, we report the first open source, comprehensive toolbox for automating the scoring of several common behavior tasks used by the neuroscience community. We show this new toolbox is robust and achieves equal or better consistency when compared to manual scoring methods. We use this toolbox to study the alterations in behavior that occur following blast-induced traumatic brain injury (bTBI), and study if these behavior patterns are altered following genetic deletion of the transcription factor Ets-like kinase 1 (Elk-1). Due to the role of Elk-1 in neuronal survival and proposed role in synaptic plasticity, we hypothesized that Elk-1 deletion would improve some neurobehavioral deficits, while impairing others, following blast exposure. In Elk-1 knockout (KO) animals, deficits in open field, spatial object recognition (SOR) and elevated zero maze performance after blast exposure disappeared, while new significant deficits appeared in spatial and associative memory. These are the first data suggesting a molecular mediator of anxiety deficits following bTBI, and represent the utility of the broad screening tool we developed. More broadly, we envision this open-source toolbox will provide a more consistent and rapid analysis of behavior across many neurological diseases, promoting the rapid discovery of novel pathways mediating disease progression and treatment.