Increased Reliability of Visually-Evoked Activity in Area V1 of the MECP2-Duplication Mouse Model of Autism.

Atypical sensory processing is now thought to be a core feature of the autism spectrum. Influential theories have proposed that both increased and decreased neural response reliability within sensory systems could underlie altered sensory processing in autism. Here, we report evidence for abnormally increased reliability of visual-evoked responses in layer 2/3 neurons of adult male and female primary visual cortex in the MECP2-duplication syndrome animal model of autism. Increased response reliability was due in part to decreased response amplitude, decreased fluctuations in endogenous activity, and an abnormal decoupling of visual-evoked activity from endogenous activity. Similar to what was observed neuronally, the optokinetic reflex occurred more reliably at low contrasts in mutant mice compared with controls. Retinal responses did not explain our observations. These data suggest that the circuit mechanisms for combining sensory-evoked and endogenous signal and noise processes may be altered in this form of syndromic autism.SIGNIFICANCE STATEMENT Atypical sensory processing is now thought to be a core feature of the autism spectrum. Influential theories have proposed that both increased and decreased neural response reliability within sensory systems could underlie altered sensory processing in autism. Here, we report evidence for abnormally increased reliability of visual-evoked responses in primary visual cortex of the animal model for MECP2-duplication syndrome, a high-penetrance single-gene cause of autism. Visual-evoked activity was abnormally decoupled from endogenous activity in mutant mice, suggesting in line with the influential "hypo-priors" theory of autism that sensory priors embedded in endogenous activity may have less influence on perception in autism.

Brief report: Revealing the nuance: Examining approaches for research with adolescents who identify with multiple racial/ethnic groups.

INTRODUCTION: Increasing racial/ethnic diversity in the United States calls for methodological approaches that capture participants who identify with multiple racial/ethnic groups. Existing approaches are oriented toward large samples (N > 500); yet, we do not know how effective these approaches are with more common smaller convenience samples. We explored how several approaches were associated with the sample distribution of racial/ethnic groups and ethnic identity using a small convenience sample. METHODS: In 2017, 320 U.S. adolescents (Mage = 16.04 years, SDage = 1.33; 59% female) responded to an open-ended question regarding their racial/ethnic group(s) in a cross-sectional survey. Seventy-five (23%) adolescents identified with multiple racial/ethnic groups. Remaining adolescents identified solely with the Asian/Hawaiian Native/Pacific Islander (19%), Black/African American (3%), European American (21%), Latinx (34%), or Native American/Alaska Native (<1%) group. RESULTS: Three approaches for adolescents with multiple racial/ethnic groups were employed. Findings indicated that the sample distributions differed across the approaches. The greatest differences were shown for Black/African American, Native American/Alaska Native, and Other Race/Ethnicity groups. Descriptively, ethnic identity also differed across the approaches. For example, multiracial/ethnic adolescents reported greater ethnic identity-exploration than their European American counterparts in one approach than in others. CONCLUSIONS: Researchers should carefully consider approaches to research with adolescents who identify with multiple racial/ethnic groups given implications for the literature. This study demonstrates the critical need to further develop approaches for capturing the complexity of race/ethnicity.

Strong versus weak embodiment: Spatial iconicity in physical, abstract, and social semantic categories.

BACKGROUND: Perceptual and action systems seem to be related to complex cognitive processes, but the scope of grounded or embodied cognition has been questioned. Zwaan and Yaxley (2003) proposed that cognitive processes of making semantic relatedness judgments can be facilitated when word pairs are presented in ways that their referents maintain their iconic configuration rather than their reverse-iconic configuration (the spatial iconicity effect). This effect has been observed in different semantic categories using specific experiments, but it is known that embodiment is highly dependent on task demands. METHOD: The present study analyzed the spatial iconicity effect in three semantic categories (physical, abstract, and social) using the same experimental criteria to determine the scope of embodied cognition. In this reaction-time experiment, 75 participants judged the semantic relatedness of 384 word pairs whose experimental items were presented in their iconic or reverse-iconic configurations. RESULTS: Two mixed-effects models with crossed random effects revealed that the interaction between word meaning and spatial position was present only for physical concepts but neither for abstract nor social concepts. CONCLUSIONS: Within the framework of strong and weak embodiment theories, the data support weak embodiment theory as the most explicative one.

Distilling vector space model scores for the assessment of constructed responses with bifactor Inbuilt Rubric method and latent variables.

In this paper, we highlight the importance of distilling the computational assessments of constructed responses to validate the indicators/proxies of constructs/trins using an empirical illustration in automated summary evaluation. We present the validation of the Inbuilt Rubric (IR) method that maps rubrics into vector spaces for concepts' assessment. Specifically, we improved and validated its scores' performance using latent variables, a common approach in psychometrics. We also validated a new hierarchical vector space, namely a bifactor IR. 205 Spanish undergraduate students produced 615 summaries of three different texts that were evaluated by human raters and different versions of the IR method using latent semantic analysis (LSA). The computational scores were validated using multiple linear regressions and different latent variable models like CFAs or SEMs. Convergent and discriminant validity was found for the IR scores using human rater scores as validity criteria. While this study was conducted in the Spanish language, the proposed scheme is language-independent and applicable to any language. We highlight four main conclusions: (1) Accurate performance can be observed in topic-detection tasks without hundreds/thousands of pre-scored samples required in supervised models. (2) Convergent/discriminant validity can be improved using measurement models for computational scores as they adjust for measurement errors. (3) Nouns embedded in fragments of instructional text can be an affordable alternative to use the IR method. (4) Hierarchical models, like the bifactor IR, can increase the validity of computational assessments evaluating general and specific knowledge in vector space models. R code is provided to apply the classic and bifactor IR method.

Characterization of Orange Peel Waste and Valorization to Obtain Reducing Sugars.

Annually, millions of tons of foods are generated with the purpose to feed the growing world population. One particular eatable is orange, the production of which in 2018 was 75.54 Mt. One way to valorize the orange residue is to produce bioethanol by fermenting the reducing sugars generated from orange peel. Hence, the objective of the present work was to determine the experimental conditions to obtain the maximum yield of reducing sugars from orange peel using a diluted acid hydrolysis process. A proximate and chemical analysis of the orange peel were conducted. For the hydrolysis, two factorial designs were prepared to measure the glucose and fructose concentration with the 3,5-DNS acid method and UV-Visible spectroscopy. The factors were acid concentration, temperature and hydrolysis time. After the hydrolysis, the orange peel samples were subjected to an elemental SEM-EDS analysis. The results for the orange peel were 73.530% of moisture, 99.261% of volatiles, 0.052% of ash, 0.687% of fixed carbon, 19.801% of lignin, 69.096% of cellulose and 9.015% of hemicellulose. The highest concentration of glucose and fructose were 24.585 and 9.709 g/L, respectively. The results highlight that sugar production is increased by decreasing the acid concentration.

Assessment and potential-site determination of a wheat straw power plant by Aspen Plus and multi-criteria GIS model.

Wheat is one of the most important crops worldwide. Mexicali, Baja California, is an important wheat producer in Mexico with an average production of 507,543 t. Wheat straw is generated as a residue which could be used for different purposes such as bioenergy, heat and power generation. In this work, an assessment and potential site determination of a biomass power plant operating with wheat straw as fuel was performed. Aspen Plus was used to evaluate a plant capacity of at least 10 MW considering the physicochemical properties and an higher heating value of 14.86 MJ kg-1 of the wheat straw from the region. The combustion produced 39.76 MW, and the overall plant efficiency was 25.52%. The development of the multi-criteria geographic information system model allowed us to assess and analyse four factors and three restrictions to determine the potential site for the biomass power plant. The factors were raw material, wheat crops, electric transmission lines, paths and roads, water canals and aqueducts, while the restrictions were localities, Ramsar sites and faults. The biomass power plant is technically and geographically feasible. The geographical coordinates of the potential site of the biomass power plant that fulfils all the criteria are 32°29'29.72″N and 115°15'39.45″W.

Representation of Rapid Image Sequences in V4 Networks.

Natural viewing often consists of sequences of brief fixations to image patches of different structure. Whether and how briefly presented sequential stimuli are encoded in a temporal-position manner is poorly understood. Here, we performed multiple-electrode recordings in the visual cortex (area V4) of nonhuman primates (Macaca mulatta) viewing a sequence of 7 briefly flashed natural images, and measured correlations between the cue-triggered population response in the presence and absence of the stimulus. Surprisingly, we found significant correlations for images occurring at the beginning and the end of a sequence, but not for those in the middle. The correlation strength increased with stimulus exposure and favored the image position in the sequence rather than image identity. These results challenge the commonly held view that images are represented in visual cortex exclusively based on their informational content, and indicate that, in the absence of sensory information, neuronal populations exhibit reactivation of stimulus-evoked responses in a way that reflects temporal position within a stimulus sequence.

Creosote Bush (Larrea tridentata) Extract Assessment as a Green Antioxidant for Biodiesel.

In this work, the antioxidant properties of methanolic extract of Larrea tridentata were assessed through the free radical scavenging method, ferric reducing antioxidant power and oxygen radical absorbance capacity. The phenolic acids content in the extract was quantified by high-performance liquid chromatography (HPLC) and the total phenol content by the Folin-Ciocalteu method. The extract was used as an antioxidant in biodiesel from canola oil composed mostly by fatty acid methyl esters identified and quantified by gas chromatography-mass spectrophotometry (GC-MS). The performance of the extract as an antioxidant was assessed by the oxidative stability index (OSI) with a Rancimat equipment at 100, 110, 120 and 130 °C. Additionally, the change of the peroxide value (PV) and the higher heating value under conditions of oxidative stress at 100 °C and air injection were measured. The antioxidant capacity of the extract reached 50,000 TAEC (micromole of Trolox antioxidant equivalent capacity per gram). The biodiesel was constituted by more than 70% of unsaturated fatty acid methyl esters (FAME), mainly methyl oleate. The time needed to reach a PV of 100 meqO2/kg was almost four times longer with an antioxidant concentration of 250 mg/L than the blank. The biodiesel showed an OSI time of 1.25 h at 110 °C, while it increased to 8.8, 15.89 and 32.27 h with the antioxidant at concentrations of 250, 500 and 1000 mg/L, respectively. The methanolic Larrea tridentata extract proved to have an antioxidant capacity and it is a green antioxidant in biodiesel to increase its oxidative stability. According to the results obtained, the L. tridentata methanolic extract is an alternative to the commercial synthetic antioxidants used in biodiesel nowadays.

Effect of high hydrostatic pressure on the polyphenols and antioxidant activity of plantain pulp (Musa paradisiaca AAB).

BACKGROUND: The impact of high-pressure processing (HPP) on the polyphenol (PP) content and antioxidant activity (AOX) of plantain pulp was evaluated. Pressures of 400, 500 and 600 MPa were applied to plantain pulp for 90 and 180 s at room temperature (25 °C). Polyphenoloxidase activity, extractable (EPP) and non-extractable PP (NEPP) contents, flavonoid content and AOX (FRAP, ABTS•+ ) were evaluated. In addition, PP identification was performed using high-performance liquid chromatography. RESULTS: Polyphenoloxidase activity was inhibited after HPP under all of the conditions studied. Increases of 110.80% and 137.40% in EPP content under conditions of 500 MPa/180 s and 600 MPa/90 s were observed with a simultaneous improvement in the AOX with increments of up to 128.71%. The treatment under conditions of 500 MPa/90 s had the highest total PP content, including the highest content of flavonoids (0.22 g ellagic acid equivalents kg-1 dry weight) and the proportion of NEPP that contained hydrolysable PPs (91.12 g gallic acid equivalents kg-1 dry weight with high AOX. The identified PPs included catechin, quercetin, gallic and hydroxybenzoic acids. CONCLUSION: HPP performed at a room temperature can be used for improving the total content of PP compounds in plantain pulp under specific pressure and time conditions. © 2016 Society of Chemical Industry.

The grid-cell normative model: Unifying 'principles'.

A normative model for the emergence of entorhinal grid cells in the brain's navigational system has been proposed (Sorscher et al., 2023. Neuron 111, 121-137). Using computational modeling of place-to-grid cell interactions, the authors characterized the fundamental nature of grid cells through information processing. However, the normative model does not consider certain discoveries that complement or contradict the conditions for such emergence. By briefly reviewing current evidence, we draw some implications on the interplay between place cell replay sequences and intrinsic grid cell oscillations related to the hippocampal-entorhinal navigation system that can extend the normative model.

High hydrostatic pressure induces synthesis of heat-shock proteins and trehalose-6-phosphate synthase in Anastrepha ludens larvae.

The Mexican fruit fly (Anastrepha ludens) is responsible for losses of up to 25% of crops such as mango and citrus fruits in Central America and México. The larval life cycle of A. ludens comprises three stages with a duration ranging from 3 to 8 days. Because of the damage caused by A. ludens, several methods of control have been studied and implemented. High hydrostatic pressures (HHP) are currently applied to foods and it is now proposed to be employed to inactivate eggs and larvae of A. ludens. Originally HHP was designed to inactivate microorganisms, since it exerts marked effects on cell morphology, and can affect enzymatic reactions and genetic mechanisms of microbial cells, with no major changes altering the sensory or nutritional quality of the foodstuff. In this study, A. ludens in two larval stages (5- and 8-day-old) were subjected to HHP treatments. The biochemical response of the larvae of A. ludens was dependent on their stage of development. The third larval stage (L3) developed a better protection mechanism based on the synthesis of stress proteins or heat-shock proteins (HSPs) and the enzyme trehalose-6-phosphate synthase, which are linked and possibly act together to achieve greater survivability to stress caused by hydrostatic pressure.

A multiconsistent computational methodology to resolve a diffusive epidemiological system with effects of migration, vaccination and quarantine.

BACKGROUND: We provide a compartmental model for the transmission of some contagious illnesses in a population. The model is based on partial differential equations, and takes into account seven sub-populations which are, concretely, susceptible, exposed, infected (asymptomatic or symptomatic), quarantined, recovered and vaccinated individuals along with migration. The goal is to propose and analyze an efficient computer method which resembles the dynamical properties of the epidemiological model. MATERIALS AND METHODS: A non-local approach is utilized for finding approximate solutions for the mathematical model. To that end, a non-standard finite-difference technique is introduced. The finite-difference scheme is a linearly implicit model which may be rewritten using a suitable matrix. Under suitable circumstances, the matrices representing the methodology are M-matrices. RESULTS: Analytically, the local asymptotic stability of the constant solutions is investigated and the next generation matrix technique is employed to calculate the reproduction number. Computationally, the dynamical consistency of the method and the numerical efficiency are investigated rigorously. The method is thoroughly examined for its convergence, stability, and consistency. CONCLUSIONS: The theoretical analysis of the method shows that it is able to maintain the positivity of its solutions and identify equilibria. The method's local asymptotic stability properties are similar to those of the continuous system. The analysis concludes that the numerical model is convergent, stable and consistent, with linear order of convergence in the temporal domain and quadratic order of convergence in the spatial variables. A computer implementation is used to confirm the mathematical properties, and it confirms the ability in our scheme to preserve positivity, and identify equilibrium solutions and their local asymptotic stability.

Molecular characterisation and biomass and metabolite production of Lactobacillus reuteri LPB P01-001: A potential probiotic.

Lactobacillus reuteri LPB P01-001 was isolated from the gastrointestinal tract of wild swine and was characterised by biochemical testing and sequencing of gene 16S rRNA. A simple and low-cost culture medium based on cane sugar (2.5% p/v) and yeast extract (1% p/v) was used in the production of this probiotic. The fermentative conditions were a) pH control at 6.5 and b) no pH control; both were set at 37°C in a 12 L slightly stirred tank bioreactor. Fermentation parameters such as the specific growth rate, productivity and yield of biomass, lactic and acetic acid levels were determined. L. reuteri LPB P01-001 behaves as an aciduric bacteria because it grows better in a low pH medium without pH control. However, the lactic acid production yield was practically half (9.22 g.L(-1)) of that obtained under a constant pH of 6.5, which reached 30.5 g.L(-1) after 28 hours of fermentation. The acetic acid production was also higher under pH-controlled fermentation, reaching 10.09 g.L(-1)after 28 hours of fermentation. These parameters may raise the interest of those committed to the efficient production of a probiotic agent for swine.

Place cells dynamically refine grid cell activities to reduce error accumulation during path integration in a continuous attractor model.

Navigation is one of the most fundamental skills of animals. During spatial navigation, grid cells in the medial entorhinal cortex process speed and direction of the animal to map the environment. Hippocampal place cells, in turn, encode place using sensory signals and reduce the accumulated error of grid cells for path integration. Although both cell types are part of the path integration system, the dynamic relationship between place and grid cells and the error reduction mechanism is yet to be understood. We implemented a realistic model of grid cells based on a continuous attractor model. The grid cell model was coupled to a place cell model to address their dynamic relationship during a simulated animal's exploration of a square arena. The grid cell model processed the animal's velocity and place field information from place cells. Place cells incorporated salient visual features and proximity information with input from grid cells to define their place fields. Grid cells had similar spatial phases but a diversity of spacings and orientations. To determine the role of place cells in error reduction for path integration, the animal's position estimates were decoded from grid cell activities with and without the place field input. We found that the accumulated error was reduced as place fields emerged during the exploration. Place fields closer to the animal's current location contributed more to the error reduction than remote place fields. Place cells' fields encoding space could function as spatial anchoring signals for precise path integration by grid cells.

Protection against Oxidative Stress and Metabolic Alterations by Synthetic Peptides Derived from Erythrina edulis Seed Protein.

The ability of multifunctional food-derived peptides to act on different body targets make them promising alternatives in the prevention/management of chronic disorders. The potential of Erythrina edulis (pajuro) protein as a source of multifunctional peptides was proven. Fourteen selected synthetic peptides identified in an alcalase hydrolyzate from pajuro protein showed in vitro antioxidant, anti-hypertensive, anti-diabetic, and/or anti-obesity effects. The radical scavenging properties of the peptides could be responsible for the potent protective effects observed against the oxidative damage caused by FeSO4 in neuroblastoma cells. Moreover, their affinity towards the binding cavity of angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) were predicted by molecular modeling. The results demonstrated that some peptides such as YPSY exhibited promising binding at both enzymes, supporting the role of pajuro protein as a novel ingredient of functional foods or nutraceuticals for prevention/management of oxidative stress, hypertension, and metabolic-alteration-associated chronic diseases.

A heuristic perspective on non-variational free energy modulation at the sleep-like edge.

BACKGROUND: The variational Free Energy Principle (FEP) establishes that a neural system minimizes a free energy function of their internal state through environmental sensing entailing beliefs about hidden states in their environment. PROBLEM: Because sensations are drastically reduced during sleep, it is still unclear how a self-organizing neural network can modulate free energy during sleep transitions. GOAL: To address this issue, we study how network's state-dependent changes in energy, entropy and free energy connect with changes at the synaptic level in the absence of sensing during a sleep-like transition. APPROACH: We use simulations of a physically plausible, environmentally isolated neuronal network that self-organize after inducing a thalamic input to show that the reduction of non-variational free energy depends sensitively upon thalamic input at a slow, rhythmic Poisson (delta) frequency due to spike timing dependent plasticity. METHODS: We define a non-variational free energy in terms of the relative difference between the energy and entropy of the network from the initial distribution (prior to activity dependent plasticity) to the nonequilibrium steady-state distribution (after plasticity). We repeated the analysis under different levels of thalamic drive - as defined by the number of cortical neurons in receipt of thalamic input. RESULTS: Entraining slow activity with thalamic input induces a transition from a gamma (awake-like state) to a delta (sleep-like state) mode of activity, which can be characterized through a modulation of network's energy and entropy (non-variational free energy) of the ensuing dynamics. The self-organizing response to low and high thalamic drive also showed characteristic differences in the spectrum of frequency content due to spike timing dependent plasticity. CONCLUSIONS: The modulation of this non-variational free energy in a network that self-organizes, seems to be an organizational network principle. This could open a window to new empirically testable hypotheses about state changes in a neural network.

Neural correlates and determinants of approach-avoidance conflict in the prelimbic prefrontal cortex.

The recollection of environmental cues associated with threat or reward allows animals to select the most appropriate behavioral responses. Neurons in the prelimbic (PL) cortex respond to both threat- and reward-associated cues. However, it remains unknown whether PL regulates threat-avoidance vs. reward-approaching responses when an animals' decision depends on previously associated memories. Using a conflict model in which male Long-Evans rats retrieve memories of shock- and food-paired cues, we observed two distinct phenotypes during conflict: (1) rats that continued to press a lever for food (Pressers) and (2) rats that exhibited a complete suppression in food seeking (Non-pressers). Single-unit recordings revealed that increased risk-taking behavior in Pressers is associated with persistent food-cue responses in PL, and reduced spontaneous activity in PL glutamatergic (PLGLUT) neurons during conflict. Activating PLGLUT neurons in Pressers attenuated food-seeking responses in a neutral context, whereas inhibiting PLGLUT neurons in Non-pressers reduced defensive responses and increased food approaching during conflict. Our results establish a causal role for PLGLUT neurons in mediating individual variability in memory-based risky decision-making by regulating threat-avoidance vs. reward-approach behaviors.

Metacomprehension skills depend on the type of text: An analysis from Differential Item Functioning.

BACKGROUND: Metacomprehension skills determine an individual reader's ability to judge their degree of learning and text comprehension and have considerable importance in their ability to learn from reading. Given that many comprehension processes are influenced by text characteristics, the aim of the present study was to analyze whether different types of text have significant impact on metacomprehension skills at two different points in primary education. METHOD: A total of 823 students (4th and 6th years of primary school, 9 to 11 years old) read three different texts (narrative, expository and discontinuous texts) taken from ECOM-PLEC.Pri, a standardized Spanish test for reading comprehension (León, Escudero, & Olmos, 2012). Students were classified by their metacomprehension skills. A Differential Item Functioning (DIF) analysis was conducted in order to analyze whether the underlying reading comprehension and metacomprehension processes differed across text types. RESULTS: Results showed a considerable divergence of performance for reading narrative texts as opposed to expository and discontinuous texts. These differences were related to academic level. CONCLUSION: Text characteristics such as the type of text can have a great impact on metacomprehension skills and, consequently, on learning.

Selective attention to question-relevant text information precedes high-quality summaries: Evidence from eye movements.

Comprehension and summarizing are closely related. As more strategic and selective processing during reading should be reflected in higher quality of summaries, the aim of this study was to use eye movement patterns to analyze how readers who produce good quality summaries process texts. 40 undergraduate students were instructed to read six expository texts in order to respond a causal question introduced in the end of the first paragraph. After reading, participants produced an oral summary of the text. Based on the quality of the summaries, participants were divided into three groups: High, Medium and Low Quality Summaries. The results revealed that readers who produced High Quality Summaries made significantly more and longer fixations and regressions in the question-relevant parts of texts when compared to the other two summary groups. These results suggest that the summary task performance could be a good predictor of the reading strategies utilized during reading.