Noninvasive Studies Research Articles

Comparing costs associated with management of antibiotic-recalcitrant recurrent urinary tract infections for one year pre- and post-electrofulguration.

To quantify and compare recurrent urinary tract infection costs between 1 year before and 1 year after electrofulguration. Following IRB approval, a well-characterized cohort of non-neurogenic women with >3 symptomatic urinary tract infections(UTIs)/year, a negative upper and lower urinary tract evaluation, and inflammatory bladder lesions (cystitis) on office cystoscopy who underwent fulguration of these lesions was analyzed. Cost of visits, imaging, labs, and medications were summed for 1-year pre- and post-fulguration using the Medicare Physician Fee Schedule, local pharmacy pricing, and institutional expenses. Before fulguration, all patients underwent clinic visit, noninvasive flow study, and flexible cystoscopy, and post-fulguration, 6-week follow-up visit and 6-month cystoscopy. Ninety-threewomen met study criteria (mean age 64), with 100% 1-year follow-up. Before fulguration, 73% of patients used daily antibiotic suppression, 6% self-start antibiotics, and 5% postcoital prophylaxis. Some also used vaginal estrogens (17%), urinary analgesics (13%), and cranberry or d-mannose supplements (7%). At 1 year post-fulguration, 82% had 0-1 infections and no cystoscopy evidence of cystitis, while 14% required additional fulguration for new cystitis sites and recurrent infections. Patients had on average 0.7 infections in the 1-year post-fulguration, which was significantly lower than pre-fulguration (p < 0.05). Mean 1-year pre-fulguration cost was $1328 (median $1071, range $291-$5564). Mean 1-year post-fulguration cost was $617 (median $467, range $275-$4580). On average, post-fulguration costs were $710 lower than pre-EF (p < 0.05). For women with antibiotic-refractory recurrent urinary tract infections and cystoscopy evidence of cystitis, fulguration was associated with a significant reduction in UTI-related costs in the 1-year post-fulguration.

Factors influencing the initiation of biologic therapy in children with severe asthma: Results of the pediatric asthma noninvasive diagnostic approaches (PANDA) study.

Despite the availability of biologics for severe pediatric asthma, real-life studies reporting on drivers behind initiating biologics and their alignment with the Global Initiative for Asthma (GINA) recommendations are lacking. We performed analysis within the pediatric asthma noninvasive diagnostic approaches study, a prospective cohort of 6- to 17-year-old children with severe asthma. Information was collected on demographic factors, symptom control, treatment, comorbidities, and diagnostic tests from medical records and questionnaires. We divided patients into "starters" or "nonstarters" based on the clinical decision to initiate biologics and performed multivariate logistic regression analysis to identify drivers behind initiating therapy. Additionally, we assessed patient suitability for biologics according to key factors in the GINA recommendations: Type 2 inflammation, frequency of exacerbations, and optimization of treatment adherence. In total, 72 children (mean age 11.5 ± 3.0 years, 65.3% male) were included (13 starters). Initiation of biologics was associated with a higher GINA treatment step (adjusted odds ratio's [aOR] = 5.0, 95%CI 1.33-18.76), steroid toxicity (aOR = 21.1, 95%CI 3.73-119.91), frequency of exacerbations (aOR = 1.6, 95%CI 1.10-2.39), improved therapy adherence (aOR = 1.7, 95%CI 1.10-2.46), Caucasian ethnicity (aOR = 0.20, 95%CI 0.05-0.80), ≥1 allergic sensitization (aOR = 0.06, 95%CI 0.004-0.97), and allergic rhinitis (aOR = 0.13, 95%CI 0.03-0.65). Furthermore, steroid toxicity was identified as an important factor for deviation from the current recommendations on biologic prescription. We identified multiple drivers and inhibitors for initiating biologics, and showed the clinical need for biologics in severe pediatric asthmatics suffering from steroid toxicity. These findings may help refine asthma management guidelines.

Evaluation of registration-based vs. manual segmentation of rhesus macaque brain MRIs.

With increasing numbers of magnetic resonance imaging (MRI) datasets becoming publicly available, researchers and clinicians alike have turned to automated methods of segmentation to enable population-level analyses of these data. Although prior research has evaluated the extent to which automated methods recapitulate "gold standard" manual segmentation methods in the human brain, such an evaluation has not yet been carried out for segmentation of MRIs of the macaque brain. Macaques offer the important opportunity to bridge gaps between microanatomical studies using invasive methods like tract tracing, neural recordings, and high-resolution histology and non-invasive macroanatomical studies using methods like MRI. As such, it is important to evaluate whether automated tools derive data of sufficient quality from macaque MRIs to bridge these gaps. We tested the relationship between automated registration-based segmentation using an open source and actively maintained NHP imaging analysis pipeline (AFNI) and gold standard manual segmentation of 4 structures (2 cortical: anterior cingulate cortex and insula; 2 subcortical: amygdala and caudate) across 37 rhesus macaques (Macaca mulatta). We identified some variability in the strength of correlation between automated and manual segmentations across neural regions and differences in relationships with demographic variables like age and sex between the two techniques.

The relationship of hemorheological blood values and blood velocity of microcirculatory bloodstream in rats` skin vessels

Non-invasive study of blood rheology is relevant, but quite complex issue. When systemic blood viscosity and hematocrit levels deviate, blood flow indicators in different parts of microvasculature change. Purpose of the study – research of blood flow characteristics in skin microcirculatory bloodstream of rats obtained by high-frequency ultrasound Dopplerography (HFUD) with given changes in rheological blood indicators. The studies were carried out on pubescent male Wistar rats. 3 experimental groups were formed. Group 1 (n = 21) “Hemodilution” – viscosity 1.99 ± 0.02 mPa*s, hematocrit 31.48 ± 0.31%. Group 2 (n = 32) “Reference values” – animals with unchanged blood levels – viscosity 2.84 ± 0.03 mPa*s, hematocrit 41.60 ± 0.3%. Group 3 (n = 32) “Erythrocytosis” – viscosity 3.95 ± 0.04 mPa*s, hematocrit 54.56 ± 0.23%. Dynamic blood viscosity in vitro studies were carried out on oscillatory viscometer. In order to evaluate hematocrit level heparinized whole blood was centrifuged in glass capillaries using; hematocrit values were assessed taking into account sedimentation of formed elements column using a hematocrit reader card. Blood flow in skin microcirculatory bloodstream of rats` left thigh area was estimated by HFUD method using Minimax-Doppler-K hardware and software system, with ultrasound transducer (frequency 20 MHz). Statistical analysis showed the models are correct. Blood indicators of the animals in three experimental groups differed statistically and significantly in terms of blood viscosity and hematocrit. Discriminant analysis was used to determine the relations between rheological blood parameters and characteristics of blood velocity in microcirculatory bloodstream which made it possible to identify the most significant characteristics of blood flow that tend to change depending on altered blood composition. These include: mean systolic velocity Vas (p 0.01), mean velocity Vam (p 0.001), mean volume velocity Qam (p 0.001), vascular resistance index RI (p 0.01) and the percentage of blood cells moving in low-speed H' (p = 0.03). The reliability of selected characteristics was checked with one-way analysis of variance; and their significance in determining membership in “Hemodilution”, “Reference values” or “Erythrocytosis” groups according to HFUD data was confirmed. Based on this analysis classification functions were generated for non-invasive dynamic blood viscosity determination according to ultrasound Dopplerography data.

Gallbladder Polyps: A Literature Review of Basic Concepts, Diagnosis and Treatment Options

Gallbladder polyps (GP) are projections of the mucosa toward the light, most of them are benign caused by cholesterol deposits, focal adenomatosis, or hyperplastic lesions secondary to a local infection. It has an estimated prevalence of 5% of the world population. Cholesterol polyps are usually formed by an asymptomatic process, rarely obstructive jaundice or cholangitis due to the blockage of distal bile ducts by detached fragments of polyps. A small number of patients may be symptomatic; cholesterolosis and adenomatosis can also cause chronic dyspeptic abdominal pain, nausea, and vomiting. Ultrasound is the main imaging modality to diagnose polyps of the gallbladder, endoscopic ultrasonography can be a useful tool in patients with clinical pictures suggestive of vesicular pathology and non-invasive imaging studies, and inconclusive. In a patient aged less than 50 years with GP, the likelihood of malignancy is minimal and does not require cholecystectomy. However, those with a size greater than or equal to 10 mm should be resected by cholecystectomy for high risk of malignancy, and those with a size less than 10 mm should be submitted to ultrasound monitoring, observing the risk characteristics during follow-up, to provide timely treatment.

The curious case of the Dana platypus and what it can teach us about how lead shotgun pellets behave in fluid preserved museum specimens and may limit their scientific value.

Fluid preserved animal specimens in the collections of natural history museums constitute an invaluable archive of past and present animal diversity. Well-preserved specimens have a shelf-life spanning centuries and are widely used for e.g. anatomical, taxonomical and genetic studies. The way specimens were collected depended on the type of animal and the historical setting. As many small mammals and birds were historically collected by shooting, large quantities of heavy metal residues, primarily lead, may have been introduced into the sample in the form of lead shot pellets. Over time, these pellets may react with tissue fluids and/or the fixation and preservation agents and corrode into lead salts. As these chemicals are toxic, they could constitute a health issue to collection staff. Additionally, heavy element chemicals interfere with several imaging technologies increasingly used for non-invasive studies, and may confound anatomical and pathological investigations on affected specimens. Here we present a case-study based on platypus (Ornithorhynchus anatinus) and other small mammals containing lead pellets from the collection of The Natural History Museum of Denmark.

Single-neuron representations of odours in the human brain

Olfaction is a fundamental sensory modality that guides animal and human behaviour1,2. However, the underlying neural processes of human olfaction are still poorly understood at the fundamental—that is, the single-neuron—level. Here we report recordings of single-neuron activity in the piriform cortex and medial temporal lobe in awake humans performing an odour rating and identification task. We identified odour-modulated neurons within the piriform cortex, amygdala, entorhinal cortex and hippocampus. In each of these regions, neuronal firing accurately encodes odour identity. Notably, repeated odour presentations reduce response firing rates, demonstrating central repetition suppression and habituation. Different medial temporal lobe regions have distinct roles in odour processing, with amygdala neurons encoding subjective odour valence, and hippocampal neurons predicting behavioural odour identification performance. Whereas piriform neurons preferably encode chemical odour identity, hippocampal activity reflects subjective odour perception. Critically, we identify that piriform cortex neurons reliably encode odour-related images, supporting a multimodal role of the human piriform cortex. We also observe marked cross-modal coding of both odours and images, especially in the amygdala and piriform cortex. Moreover, we identify neurons that respond to semantically coherent odour and image information, demonstrating conceptual coding schemes in olfaction. Our results bridge the long-standing gap between animal models and non-invasive human studies and advance our understanding of odour processing in the human brain by identifying neuronal odour-coding principles, regional functional differences and cross-modal integration.

Understanding the interaction forces between shield-triggered autoinjectors and skin: an in-depth noninvasive study

ABSTRACT Objective This noninvasive study aimed to understand the interaction between shield-triggered autoinjectors (AI) and skin at the point of activation, hypothesizing that the AI’s housing absorbs a significant amount of the user-applied force depending on shield design and skin characteristics. Methods Twenty-seven volunteers used a test device measuring applied force versus shield force and indentation depth relative to shield length (2,4,6,8 mm) in standing and sitting positions. Results Significant differences were found between applied and shield force for the different shield lengths. Shorter shields resulted in significantly lower force transfer coefficients, with means ranging from 0.72 for the 2 mm shield to 0.94 for the 8 mm shield. ANOVA revealed statistically significant factors (p < .05), including position and gender, with females generally having lower coefficient values. Indentation depth increased with higher forces and varied significantly between positions without significant shield length impact. Conclusion The findings confirm that an increase in shield length at the point of activation reduces skin friction with the housing, resulting in less force loss and a lower device activation force perceived by the user. Force loss can be further reduced by standing up. Understanding device-tissue interactions will support development of better AIs with fewer user failures.

Liver Fibrosis Leading to Cirrhosis: Basic Mechanisms and Clinical Perspectives.

Liver fibrosis is the pathological deposition of extracellular matrix rich in fibrillar collagen within the hepatocytes in response to chronic liver injury due to various causes. As the condition advances, it can progress to cirrhosis, the late stages of which are irreversible. Multiple pathophysiological mechanisms and cell types are responsible for the progression of liver fibrosis and cirrhosis. Hepatic stellate cells and myofibroblast activation represent a key event in fibrosis. Capillarization of liver sinusoidal endothelial cells further contributes to extracellular matrix deposition and an increase in portal pressure. Macrophages and neutrophils produce inflammatory cytokines and participate in activating hepatic stellate cells. Although initially believed to be irreversible, early stages of fibrosis are now found to be reversible. Furthermore, advances in noninvasive imaging and serum studies have changed and improved how cirrhosis can be evaluated and monitored. Although there are currently no specific approved therapies to reverse liver fibrosis, management of underlying diseases has been found to halt the progression, and to an extent, even reverse liver fibrosis, preventing further liver injury and cirrhosis-related complications.

Awake Craniotomy in Epilepsy Surgery: A Case Series and Proposal for Three Different Scenarios.

Awake craniotomy (AWC) allows intraoperative evaluation of functions involving the cortical surface and subcortical fibers. In epilepsy surgery, indications for and the role of AWC have not been established because evaluation with intracranial electrodes is considered the gold standard. We report herein our case series of patients who underwent AWC in epilepsy surgery and propose the scenarios for and roles of AWC. Patients who underwent AWC in epilepsy surgery at our institutions between 2014 and 2023 were included. Information about age, sex, etiology, location of epileptogenicity, seizure type, use of intracranial electrode placement, surgical complications, neurological deficits, additional surgery, and seizure outcomes was reviewed. Following a diagnostic and treatment flow for epilepsy surgery, we clarified three different scenarios and roles for AWC. Ten patients underwent AWC. Three patients underwent AWC after non-invasive evaluations. Two patients underwent AWC after intracranial evaluation with stereotactic electroencephalography (SEEG). Five patients underwent AWC after intracranial evaluation with subdural grid electrodes (SDG). Among these, two patients were initially evaluated with SEEG and with SDG thereafter. One patient reported slight numbness in the hand, and one patient showed slight cognitive decline. Seizure outcomes according to the Engel outcome scale were class 1A in three patients, IIA in two patients, IIIA in four patients, and IVA in one patient. AWC can be used for purposes of epilepsy surgery in different situations, either immediately after non-invasive studies or as an additional invasive step after invasive monitoring with either SEEG or SDG. The application of AWC should be individualized according to each patient's specific characteristics.

Machine learning algorithm for predicting seizure control after temporal lobe resection using peri-ictal electroencephalography

Brain resection is curative for a subset of patients with drug resistant epilepsy but up to half will fail to achieve sustained seizure freedom in the long term. There is a critical need for accurate prediction tools to identify patients likely to have recurrent postoperative seizures. Results from preclinical models and intracranial EEG in humans suggest that the window of time immediately before and after a seizure (“peri-ictal”) represents a unique brain state with implications for clinical outcome prediction. Using a dataset of 294 patients who underwent temporal lobe resection for seizures, we show that machine learning classifiers can make accurate predictions of postoperative seizure outcome using 5 min of peri-ictal scalp EEG data that is part of universal presurgical evaluation (AUC 0.98, out-of-group testing accuracy > 90%). This is the first approach to seizure outcome prediction that employs a routine non-invasive preoperative study (scalp EEG) with accuracy range likely to translate into a clinical tool. Decision curve analysis (DCA) shows that compared to the prevalent clinical-variable based nomogram, use of the EEG-augmented approach could decrease the rate of unsuccessful brain resections by 20%.

Beyond Pallidal or Subthalamic Deep Brain Stimulation to Treat Dystonia.

Deep brain stimulation of the subthalamic nucleus and globus pallidus internus is approved by the Food and Drug Administration for treating dystonia. Both targets have shown effectiveness in improving symptoms, but post-operative outcomes can vary significantly among patients. This variability has led researchers to explore alternative neuromodulation targets that might offer more consistent results. Emerging research has highlighted several promising new targets for DBS in dystonia. This review examines pre-clinical and clinical data on novel DBS targets for dystonia and explores non-invasive neuromodulation studies that shed light on the disease's underlying pathological circuitry.

Variational Mode Decomposition Analysis of Electroencephalograms during General Anesthesia: Using the Grey Wolf Optimizer to Determine Hyperparameters.

Frequency analysis via electroencephalography (EEG) during general anesthesia is used to develop techniques for measuring anesthesia depth. Variational mode decomposition (VMD) enables mathematical optimization methods to decompose EEG signals into natural number intrinsic mode functions with distinct narrow bands. However, the analysis requires the a priori determination of hyperparameters, including the decomposition number (K) and the penalty factor (PF). In the VMD analysis of EEGs derived from a noninterventional and noninvasive retrospective observational study, we adapted the grey wolf optimizer (GWO) to determine the K and PF hyperparameters of the VMD. As a metric for optimization, we calculated the envelope function of the IMF decomposed via the VMD method and used its envelope entropy as the fitness function. The K and PF values varied in each epoch, with one epoch being the analytical unit of EEG; however, the fitness values showed convergence at an early stage in the GWO algorithm. The K value was set to 2 to capture the α wave enhancement observed during the maintenance phase of general anesthesia in intrinsic mode function 2 (IMF-2). This study suggests that using the GWO to optimize VMD hyperparameters enables the construction of a robust analytical model for examining the EEG frequency characteristics involved in the effects of general anesthesia.

P168 CHARACTERIZATION OF THE HEMODYNAMIC PATTERN OF CONTROLLED HYPERTENSIVE PATIENTS

Background: Hemodynamic alterations have been described in hypertensive disease. However, we still do not know if the identification of an altered hemodynamic pattern in patients with controlled hypertension could predict cardiovascular risk or evolution of hypertension. Objective: to identify the hemodynamic pattern of hypertensive patients with BP values in goals. Methods: Controlled hypertensive subjects were recruited (n = 107) and included a control group of normotensive subjects (n: 35.9). A non-invasive hemodynamic study (Z Logic, lying down / standing) was performed, and the cardiac index (CI) and vascular resistance index (VRI) data were recorded for the determination of the hemodynamic pattern. Hypodynamic pattern was considered: CI &lt;2.5 L / min / m2 and VRI&gt; 2500 dynas.seg.cm-5.m2; Hyperdynamic pattern IC&gt; 4,4 L / min / m2 and VRI &lt;2500 dynas.seg.cm-5.m2 Results: The SBP / DBP of the HTA group was 133.09 +/- 6.01 / 82.4 +/-7.2 mm Hg; and of the NT group was SBP/ DBP 123.6 +/- 9.7 / 75.5 +/- 8.9. The CI and VRI of the HTA group obtained was 2.81 l / m2 / min and 2842.31 dynas that, without corresponding to a hypodynamic pattern, showed a predominance of the VRI increase. In the control group of NT subjects, the values were 3.23 and 2289.23, respectively, corresponding to a normal pattern. The values obtained were different between both groups (p &lt;.05). Conclusions: Controlled hypertensive patients with hypertension goals have a hemodynamics pattern with an increase in the VRI different from that of normotensive subjects. These results coincide with those reported by Ferrario and col. The relevance of the imbalance found could only be analyzed in the context of long-term follow-up to identify whether it is a predictor of CV events and / or complications.

Post-Pulmonary Embolism Phenotypes Described by Invasive Cardiopulmonary Exercise Testing

BackgroundPost pulmonary embolism (PE) dyspnea is common. Existing non-invasive studies have demonstrated that post PE dyspnea is associated with elevations in right ventricular afterload, dead space ventilation, and deconditioning. We aimed to use invasive cardiopulmonary exercise testing (iCPET) parameters in patients with post PE dyspnea to identify unique physiologic phenotypes. Research QuestionAre there distinct post pulmonary embolism dyspnea physiologic phenotypes described with iCPET? Study Design and MethodsPatients were enrolled at the time of acute PE and through our pulmonary hypertension and dyspnea clinic. ICPET was performed if there was high suspicion for pulmonary hypertension or if there was unexplained dyspnea. A hierarchical cluster analysis was performed to identify dyspnea phenotypes. ICPET parameters assessing pulmonary hemodynamics, ventilation, and peripheral oxygen utilization were then compared within and across each cluster and with iCPET controls against peak oxygen consumption (Peak VO2). Results173 patients were enrolled. Sixty-seven patients underwent iCPET. All patients had reductions in Peak VO2 and peak cardiac index relative to controls. Three clusters were identified. Cluster one was defined by having elevated RV afterload and impaired ventilatory efficiency. Cluster two had elevated RV afterload with reductions in respiratory mechanics. Cluster three had mild derangement in RV afterload with mild reductions in peak cardiac output. InterpretationiCPET reveals significant heterogeneity in post PE dyspnea. Three phenotypes are characterized by differences in RV afterload, ventilatory efficiency, respiratory mechanics, and peripheral oxygen utilization.

Nonparametric distributions of tensor-valued Lorentzian diffusion spectra for model-free data inversion in multidimensional diffusion MRI.

Magnetic resonance imaging (MRI) is the method of choice for noninvasive studies of micrometer-scale structures in biological tissues via their effects on the time- and frequency-dependent (restricted) and anisotropic self-diffusion of water. While new designs of time-dependent magnetic field gradient waveforms have enabled disambiguation between different aspects of translational motion that are convolved in traditional MRI methods relying on single pairs of field gradient pulses, data analysis for complex heterogeneous materials remains a challenge. Here, we propose and demonstrate nonparametric distributions of tensor-valued Lorentzian diffusion spectra, or "D(ω) distributions," as a general representation with sufficient flexibility to describe the MRI signal response from a wide range of model systems and biological tissues investigated with modulated gradient waveforms separating and correlating the effects of restricted and anisotropic diffusion.

Chilean consensus by expert panel using the Delphi technique for primary and secondary prevention of gastric cancer

IntroductionGastric cancer (GC) is the first cause of cancer-related death in Chile and 6th in Latin America and the Caribbean (LAC). Helicobacter pylori (H. pylori) is the main gastric carcinogen, and its treatment reduces GC incidence and mortality. Esophageal-gastro-duodenoscopy (EGD) allows for the detection of premalignant conditions and early-stage GC. Mass screening programs for H. pylori infection and screening for premalignant conditions and early-stage GC are not currently implemented in LAC. The aim of this study is to establish recommendations for primary and secondary prevention of GC in asymptomatic standard-risk populations in Chile. MethodsTwo on-line synchronous workshops and a seminar were conducted with Chilean experts. A Delphi panel consensus was conducted over 2 rounds to achieve >80% agreement on proposed primary and secondary prevention strategies for the population stratified by age groups. Results10, 12, and 12 experts participated in two workshops and a seminar, respectively. In the Delphi panel, 25 out of 37 experts (77.14%) and 28 out of 52 experts (53.85%) responded. For the population aged 16–34, there was no consensus on non-invasive testing and treatment for H. pylori, and the use of EGD was excluded. For the 35–44 age group, non-invasive testing and treatment for H. pylori is recommended, followed by subsequent test-of-cure using non-invasive tests (stool antigen test or urea breath test). In the ≥45 age group, a combined strategy is recommended, involving H. pylori testing and treatment plus non-invasive biomarkers (H. pylori IgG serology and serum pepsinogens I and II); subsequently, a selected group of subjects will undergo EGD with gastric biopsies (Sydney Protocol), which will be used to stratify surveillance according to the OLGA classification (Operative Link for Gastritis Assessment); every 3 years for OLGA III–IV and every 5 years for OLGA I–II. ConclusionA “test-and-treat” strategy for H. pylori infection based on non-invasive studies (primary prevention) is proposed in the 35–44 age group, and a combined strategy (serology and EGD) is recommended for the ≥45 age group (primary and secondary prevention). These strategies are potentially applicable to other countries in LAC.

Updates in Endoscopic Retrograde Cholangiopancreatography

Endoscopic retrograde cholangiopancreatography (ERCP) is a specialised endoscopic procedure for managing pancreatic and biliary diseases. Earlier in the 1970s, ERCP was mainly used for diagnostic purposes to evaluate the biliary and pancreatic ducts and surrounding structures. But nowadays, as noninvasive imaging studies advance, it is primarily used for therapeutic purposes though it is used for therapeutic and diagnostic purposes.Therapeutic ERCP is broadly used in conditions that lead to impairment in bile flow and leak. The requirement of the ERCP extended further for evaluation of pancreatitis of unknown aetiology, preoperative evaluation of the patient with chronic pancreatitis and evaluation of the sphincter of Oddi by manometry.Patients should be selected with a clear-cut indication for ERCP, avoiding unnecessary or marginally indicated ERCP, especially in high-risk patients. ERCP is usually performed using a dedicated side-viewing endoscope with the patient positioned prone on a fluoroscopy table under sedation or general anaesthesia. Proper positioning of the duodenoscope is the key to cannulation of the pancreatic or common bile ducts.

Decoding EEG for optimizing naturalistic memory

Background:Spectral features of human electroencephalographic (EEG) recordings during learning predict subsequent recall variability. New method:Capitalizing on these fluctuating neural features, we develop a non-invasive closed-loop (NICL) system for real-time optimization of human learning. Participants play a virtual navigation-and-memory game; recording multi-session data across days allowed us to build participant-specific classification models of recall success. In subsequent closed-loop sessions, our platform manipulated the timing of memory encoding, selectively presenting items during periods of predicted good or poor memory function based on EEG features decoded in real time. Results:The induced memory effect (the difference between recall rates when presenting items during predicted good vs. poor learning periods) increased with the accuracy of neural decoding. Comparison with Existing Methods:This study demonstrates greater-than-chance memory decoding from EEG recordings in a naturalistic virtual navigation task with greater real-world validity than basic word-list recall paradigms. Here we modulate memory by timing stimulus presentation based on noninvasive scalp EEG recordings, whereas prior closed-loop studies for memory improvement involved intracranial recordings and direct electrical stimulation. Other noninvasive studies have investigated the use of neurofeedback or remedial study for memory improvement. Conclusions:These findings present a proof-of-concept for using non-invasive closed-loop technology to optimize human learning and memory through principled stimulus timing, but only in those participants for whom classifiers reliably predict out-of-sample memory function.

Non-invasive laser speckle contrast imaging (LSCI) of extra-embryonic blood vessels in intact avian eggs at early developmental stages.

Imaging blood vessels in early-stage avian embryos has a wide range of practical applications for developmental biology studies, drug and vaccine testing, and early sex determination. Optical imaging, such as brightfield transmission imaging, offers a compelling solution due to its safe non-ionizing radiation, and operational benefits. However, it comes with challenges, such as eggshell opacity and light scattering. To address these, we have revisited an approach based on laser speckle contrast imaging (LSCI) and demonstrated a high-quality, comprehensive, and non-invasive visualization of blood vessels in few-days-old chicken eggs, with blood vessels as small as 100 µm in diameter (with LSCI profile full-width-at-half-maximum of 275 µm). We present its non-invasive use for monitoring blood flow, measuring the embryo's heartbeat, and determining the embryo's developmental stages using machine learning with 85% accuracy from stage HH15 to HH22. This method can potentially be used for non-invasive longitudinal studies of cardiovascular development and angiogenesis, as well as egg screening for the poultry industry.