A mathematical model of microglia glucose metabolism and lactylation with positive feedback.

In this paper, we present and analyze a model for metabolism and lactylation in a single microglia. The model includes positive feedback from lactylation in the glycolytic pathway, and links metabolism and inflammation. Specific pathways include the transition of glucose to pyruvate to lactate in a microglia, as well as the gradient transport of glucose and lactate into and out of the cell.

Effects of local mutations in quadratic iterations.

We introduce mutations in the process of discrete iterations of complex quadratic maps in the family fc(z)=z2+c. More specifically, we consider a "correct" function fc1 acting on the complex plane. A "mutation" fc0 is a different ("erroneous") map acting on a locus of given radius r around a mutation focal point ξ∗.

Synchronization and Clustering in Complex Quadratic Networks.

Synchronization and clustering are well studied in the context of networks of oscillators, such as neuronal networks. However, this relationship is notoriously difficult to approach mathematically in natural, complex networks. Here, we aim to understand it in a canonical framework, using complex quadratic node dynamics, coupled in networks that we call complex quadratic networks (CQNs).

A Comprehensive Multilevel Analysis of the Bucharest Early Intervention Project: Causal Effects on Recovery From Early Severe Deprivation.

Objective: The Bucharest Early Intervention Project is the first randomized controlled trial of foster care as an alternative to institutional care. The authors synthesized data from nearly 20 years of assessments of the trial to determine the overall intervention effect size across time points and developmental domains. The goal was to quantify the overall effect of the foster care intervention on children's outcomes and examine sources of variation in this effect, including domain, age, and sex assigned at birth.

Foster care leads to sustained cognitive gains following severe early deprivation.

This study examined longitudinal data from the Bucharest Early Intervention Project, a randomized controlled trial of foster care as an alternative to institutional care following exposure to severe psychosocial deprivation. We report data from 135 participants assessed in early adulthood (age 18 y). We find that 16 y after randomization occurred, those who had been randomized to high-quality foster care had significantly higher IQ scores (9 points, 0.

Insights into pathological mechanisms and interventions revealed by analyzing a mathematical model for cone metabolism.

This work analyzes a mathematical model for the metabolic dynamics of a cone photoreceptor, which is the first model to account for energy generation from fatty acids oxidation of shed photoreceptor outer segments (POS). Multiple parameter bifurcation analysis shows that joint variations in external glucose, the efficiency of glucose transporter 1 (GLUT1), lipid utilization for POS renewal, and oxidation of fatty acids affect the cone's metabolic vitality and its capability to adapt under glucose-deficient conditions. The analysis further reveals that when glucose is scarce, cone viability cannot be sustained by only fueling energy production in the mitochondria, but it also requires supporting anabolic processes to create lipids necessary for cell maintenance and repair.

Estimating the glutamate transporter surface density in distinct sub-cellular compartments of mouse hippocampal astrocytes.

Glutamate transporters preserve the spatial specificity of synaptic transmission by limiting glutamate diffusion away from the synaptic cleft, and prevent excitotoxicity by keeping the extracellular concentration of glutamate at low nanomolar levels. Glutamate transporters are abundantly expressed in astrocytes, and previous estimates have been obtained about their surface expression in astrocytes of the rat hippocampus and cerebellum. Analogous estimates for the mouse hippocampus are currently not available.

Dynamic coupling between the COVID-19 epidemic timeline and the behavioral response to PAUSE in New York State counties.

Behavioral epidemiology suggests that there is a tight dynamic coupling between the timeline of an epidemic outbreak, and the social response in the affected population (with a typical course involving physical distancing between individuals, avoidance of large gatherings, wearing masks, etc). We study the bidirectional coupling between the epidemic dynamics of COVID-19 and the population social response in the state of New York, between March 1, 2020 (which marks the first confirmed positive diagnosis in the state), until June 20, 2020. This window captures the first state-wide epidemic wave, which peaked to over 11,000 confirmed cases daily in April (making New York one of the US states most severely affected by this first wave), and subsided by the start of June to a count of consistently under 1,500 confirmed cases per day (suggesting temporary state-wide control of the epidemic).

Management strategies in a SEIR-type model of COVID 19 community spread.

The 2019 Novel Corona virus infection (COVID 19) is an ongoing public health emergency of international focus. Significant gaps persist in our knowledge of COVID 19 epidemiology, transmission dynamics, investigation tools and management, despite (or possibly because of) the fact that the outbreak is an unprecedented global threat. On the positive side, enough is currently known about the epidemic process to permit the construction of mathematical predictive models.

Course of the first month of the COVID 19 outbreak in the New York State counties.

We illustrate and study the evolution of reported infections over the month of March in New York State as a whole, as well as in each individual county in the state. We identify piecewise exponential trends, and search for correlations between the timing and dynamics of these trends and statewide mandated measures on testing and social distancing. We conclude that the reports on April 1 may be dramatically under-representing the actual number of statewide infections, an idea which is supported by more recent retroactive estimates based on serological studies.

A pharmacokinetic model of lead absorption and calcium competitive dynamics.

Lead is a naturally-occurring element. It has been known to man for a long time, and it is one of the longest established poisons. The current consensus is that no level of lead exposure should be deemed "safe".

Global and local excitation and inhibition shape the dynamics of the cortico-striatal-thalamo-cortical pathway.

The cortico-striatal-thalamo-cortical (CSTC) pathway is a brain circuit that controls movement execution, habit formation and reward. Hyperactivity in the CSTC pathway is involved in obsessive compulsive disorder (OCD), a neuropsychiatric disorder characterized by the execution of repetitive involuntary movements. The striatum shapes the activity of the CSTC pathway through the coordinated activation of two classes of medium spiny neurons (MSNs) expressing D1 or D2 dopamine receptors.

An Interpretative Phenomenological Analysis of a Religious Conversion.

Religious conversion is an important phenomenon in contemporary religious climate, but existing psychology research work is mostly based on quantitative methods. In an attempt to contribute to this field, the present study proposes a qualitative exploration of religious conversion. The in-depth interview of a French woman is examined in order to investigate her experience of religious conversion, 40 years prior.

Applying fMRI complexity analyses to the single subject: a case study for proposed neurodiagnostics.

Nonlinear dynamic tools have been statistically validated at the group level to identify subtle differences in system wide regulation of brain meso-circuits, often increasing clinical sensitivity over conventional analyses alone. We explored the feasibility of extracting information at the single-subject level, illustrating two pairs of healthy individuals with psychological differences in stress reactivity. We applied statistical and nonlinear dynamic tools to capture key characteristics of the prefrontal-limbic loop.

A mathematical model of reward and executive circuitry in obsessive compulsive disorder.

The neuronal circuit that controls obsessive and compulsive behaviors involves a complex network of brain regions (some with known involvement in reward processing). Among these are cortical regions, the striatum and the thalamus (which compose the CSTC pathway), limbic areas such as the amygdala and the hippocampus, as well as dopamine pathways. Abnormal dynamic behavior in this brain network is a hallmark feature of patients with increased anxiety and motor activity, like the ones affected by OCD.

Neural Network Spectral Robustness under Perturbations of the Underlying Graph.

Recent studies have been using graph-theoretical approaches to model complex networks (such as social, infrastructural, or biological networks) and how their hardwired circuitry relates to their dynamic evolution in time. Understanding how configuration reflects on the coupled behavior in a system of dynamic nodes can be of great importance, for example, in the context of how the brain connectome is affecting brain function. However, the effect of connectivity patterns on network dynamics is far from being fully understood.

The Effects of Early Institutionalization and Foster Care Intervention on Children's Social Behaviors at Age 8.

The present study compared the social behaviors of 8-year-old previously institutionalized Romanian children from the Bucharest Early Intervention Project (BEIP) in two groups: 1) children randomized to foster care homes (FCG), and 2) children randomized to care as usual (remaining in institutions) (CAUG). Children were observed interacting with an age and gender-matched unfamiliar, non-institutionalized peer from the community (NIG) during six interactive tasks, and their behavior was coded for speech reticence, social engagement, task orientation, social withdrawal, and conversational competence. Group comparisons revealed that FCG children were rated as significantly less reticent during a speech task than CAUG children.

Nonlinear network dynamics under perturbations of the underlying graph.

Many natural systems are organized as networks, in which the nodes (be they cells, individuals or populations) interact in a time-dependent fashion. The dynamic behavior of these networks depends on how these nodes are connected, which can be understood in terms of an adjacency matrix and connection strengths. The object of our study is to relate connectivity to temporal behavior in networks of coupled nonlinear oscillators.

Input statistics and Hebbian cross-talk effects.

As an extension of prior work, we studied inspecific Hebbian learning using the classical Oja model. We used a combination of analytical tools and numerical simulations to investigate how the effects of synaptic cross talk (which we also refer to as synaptic inspecificity) depend on the input statistics. We investigated a variety of patterns that appear in dimensions higher than two (and classified them based on covariance type and input bias).

Network connectivity modulates power spectrum scale invariance.

Measures of complexity are sensitive in detecting disease, which has made them attractive candidates for diagnostic biomarkers; one complexity measure that has shown promise in fMRI is power spectrum scale invariance (PSSI). Even if scale-free features of neuroimaging turn out to be diagnostically useful, however, their underlying neurobiological basis is poorly understood. Using modeling and simulations of a schematic prefrontal-limbic meso-circuit, with excitatory and inhibitory networks of nodes, we present here a framework for how network density within a control system can affect the complexity of signal outputs.

Human gender differences in the perception of conspecific alarm chemosensory cues.

It has previously been established that, in threatening situations, animals use alarm pheromones to communicate danger. There is emerging evidence of analogous chemosensory "stress" cues in humans. For this study, we collected alarm and exercise sweat from "donors," extracted it, pooled it and presented it to 16 unrelated "detector" subjects undergoing fMRI.

The role of simvastatin in the therapeutic approach of rheumatoid arthritis.

The pleiotropic effects of statins, especially the anti-inflammatory and immunomodulatory ones, indicate that their therapeutic potential might extend beyond cholesterol lowering and cardiovascular disease to other inflammatory disorders such as rheumatoid arthritis. Therefore, we undertook a prospective cohort study to evaluate the efficacy and safety of simvastatin used for inflammation control in patients with rheumatoid arthritis. One hundred patients with active rheumatoid arthritis divided into two equal groups (the study one who received 20 mg/day of simvastatin in addition to prior DMARDs and the control one) were followed up over six months during three study visits.

Effects of early intervention and the moderating effects of brain activity on institutionalized children's social skills at age 8.

The present study examined the social skills of previously institutionalized, 8-y-old Romanian children from the Bucharest Early Intervention Project and the influence of attachment security and brain electrical activity (alpha power) on these skills. Participants included children randomized to an intervention involving foster care [Foster Care Group (FCG)], children randomized to remain in institutions [Care As Usual Group (CAUG)], and never-institutionalized children living with their families in the Bucharest community [Never-Institutionalized Group (NIG)]. A continuous rating of children's attachment security to their primary caregiver was assessed at 42 mo of age.

Power spectrum scale invariance identifies prefrontal dysregulation in paranoid schizophrenia.

Theory and experimental evidence suggest that complex living systems function close to the boundary of chaos, with erroneous organization to an improper dynamical range (too stiff or chaotic) underlying system-wide dysregulation and disease. We hypothesized that erroneous organization might therefore also characterize paranoid schizophrenia, via optimization abnormalities in the prefrontal-limbic circuit regulating emotion. To test this, we acquired fMRI scans from 35 subjects (N = 9 patients with paranoid schizophrenia and N = 26 healthy controls), while they viewed affect-valent stimuli.

Mechanisms explaining transitions between tonic and phasic firing in neuronal populations as predicted by a low dimensional firing rate model.

Several firing patterns experimentally observed in neural populations have been successfully correlated to animal behavior. Population bursting, hereby regarded as a period of high firing rate followed by a period of quiescence, is typically observed in groups of neurons during behavior. Biophysical membrane-potential models of single cell bursting involve at least three equations.