The Effects of a Short Virtual Reality Training Program on Dynamic Balance in Tennis Players

This study aimed to analyze the effects of a 5 min virtual reality training program (VR) on dynamic balance in tennis players. Fifty-eight college tennis players (mean age 22.9 ± 3.1 years, weight 73.9 ± 10.8 kg, height 176.6 ± 8.4 cm) were allocated to either the control group (placebo) (CG, n = 20) or the right-handed experimental group (RTG, n = 20) and left-handed experimental group (LTG, n = 18), both of which took part in the 5 min VR intervention program. Pre-tests included anthropometric measures and the Y Balance Test (YBT), and the post-test was the Y Balance Test (YBT). Three YBT trials were performed in anterior (ANT), posterolateral (PL), and posteromedial (PM) directions. After the training intervention, in the right-handed experimental group (RTG), significant differences were observed for two variables: anterior reach (right foot) (p = 0.00) and posterior medial reach (right foot) (p = 0.03). In other analyzed variables, there were no significant differences. Additionally, the effect size was small. In the left-handed experimental group (LTG), statistically significant improvements were identified in five out of six analyzed variables: anterior reach (left foot) (p = 0.00), posterior medial reach (left foot) (p = 0.00), posterior lateral reach (left foot) (p = 0.00), posterior medial reach (right foot) (p = 0.00), and posterior lateral reach (right foot) (p = 0.00). The effect size ranged between small and medium. No significant changes were observed in the control group (CG) after the training intervention. Moreover, for all variables, the time*group interaction is determined. Anterior reach (left foot), posterior medial reach (left foot), posterior medial reach (right foot), and posterior lateral reach (right foot) showed significant interactions (F = 3.04, p = 0.05; F = 3.50, p = 0.03; F = 6.08, p = 0.00; and F = 4.69, p = 0.01). The outcome of this study leads us to a further understanding that if a player were to partake in VR activity, it could show a positive effect on their dynamic balance performance.

Influence of spatial frequency in visual stimuli for cVEP-based BCIs: evaluation of performance and user experience

Code-modulated visual evoked potentials (c-VEPs) are an innovative control signal utilized in brain-computer interfaces (BCIs) with promising performance. Prior studies on steady-state visual evoked potentials (SSVEPs) have indicated that the spatial frequency of checkerboard-like stimuli influences both performance and user experience. Spatial frequency refers to the dimensions of the individual squares comprising the visual stimulus, quantified in cycles (i.e., number of black-white squares pairs) per degree of visual angle. However, the specific effects of this parameter on c-VEP-based BCIs remain unexplored. Therefore, the objective of this study is to investigate the role of spatial frequency of checkerboard-like visual stimuli in a c-VEP-based BCI. Sixteen participants evaluated selection matrices with eight spatial frequencies: C001 (0 c/°, 1×1 squares), C002 (0.15 c/°, 2×2 squares), C004 (0.3 c/°, 4×4 squares), C008 (0.6 c/°, 8×8 squares), C016 (1.2 c/°, 16×16 squares), C032 (2.4 c/°, 32×32 squares), C064 (4.79 c/°, 64×64 squares), and C128 (9.58 c/°, 128×128 squares). These conditions were tested in an online spelling task, which consisted of 18 trials each conducted on a 3×3 command interface. In addition to accuracy and information transfer rate (ITR), subjective measures regarding comfort, ocular irritation, and satisfaction were collected. Significant differences in performance and comfort were observed based on different stimulus spatial frequencies. Although all conditions achieved mean accuracy over 95% after 2.1 s of trial duration, C016 stood out in terms user experience. The proposed condition not only achieved a mean accuracy of 96.53% and 164.54 bits/min with a trial duration of 1.05s, but also was reported to be significantly more comfortable than the traditional C001 stimulus. Since both features are key for BCI development, higher spatial frequencies than the classical black-to-white stimulus might be more adequate for c-VEP systems. Hence, we assert that the spatial frequency should be carefully considered in the development of future applications for c-VEP-based BCIs.

Comparison of Two Paradigms Based on Stimulation with Images in a Spelling Brain-Computer Interface

A P300-based speller can be used to control a home automation system via brain activity. Evaluation of the visual stimuli used in a P300-based speller is a common topic in the field of brain-computer interfaces (BCIs). The aim of the present work is to compare, using the usability approach, two types of stimuli that have provided high performance in previous studies. Twelve participants controlled a BCI under two conditions, which varied in terms of the type of stimulus employed: a red famous face surrounded by a white rectangle (RFW) and a range of neutral pictures (NPs). The usability approach included variables related to effectiveness (accuracy and information transfer rate), efficiency (stress and fatigue), and satisfaction (pleasantness and System Usability Scale and Affect Grid questionnaires). The results indicated that there were no significant differences in effectiveness, but the system that used NPs was reported as significantly more pleasant. Hence, since satisfaction variables should also be considered in systems that potential users are likely to employ regularly, the use of different NPs may be a more suitable option than the use of a single RFW for the development of a home automation system based on a visual P300-based speller.

The Normobaric Oxygen Paradox-Hyperoxic Hypoxic Paradox: A Novel Expedient Strategy in Hematopoiesis Clinical Issues

Hypoxia, even at non-lethal levels, is one of the most stressful events for all aerobic organisms as it significantly affects a wide spectrum of physiological functions and energy production. Aerobic organisms activate countless molecular responses directed to respond at cellular, tissue, organ, and whole-body levels to cope with oxygen shortage allowing survival, including enhanced neo-angiogenesis and systemic oxygen delivery. The benefits of hypoxia may be evoked without its detrimental consequences by exploiting the so-called normobaric oxygen paradox. The intermittent shift between hyperoxic-normoxic exposure, in addition to being safe and feasible, has been shown to enhance erythropoietin production and raise hemoglobin levels with numerous different potential applications in many fields of therapy as a new strategy for surgical preconditioning aimed at frail patients and prevention of postoperative anemia. This narrative review summarizes the physiological processes behind the proposed normobaric oxygen paradox, focusing on the latest scientific evidence and the potential applications for this strategy. Future possibilities for hyperoxic-normoxic exposure therapy include implementation as a synergistic strategy to improve a patient's pre-surgical condition, a stimulating treatment in critically ill patients, preconditioning of athletes during physical preparation, and, in combination with surgery and conventional chemotherapy, to improve patients' outcomes and quality of life.

Effect of Stimulus Size in a Visual ERP-Based BCI under RSVP

Rapid serial visual presentation (RSVP) is currently one of the most suitable paradigms for use with a visual brain-computer interface based on event-related potentials (ERP-BCI) by patients with a lack of ocular motility. However, gaze-independent paradigms have not been studied as closely as gaze-dependent ones, and variables such as the sizes of the stimuli presented have not yet been explored under RSVP. Hence, the aim of the present work is to assess whether stimulus size has an impact on ERP-BCI performance under the RSVP paradigm. Twelve participants tested the ERP-BCI under RSVP using three different stimulus sizes: small (0.1 × 0.1 cm), medium (1.9 × 1.8 cm), and large (20.05 × 19.9 cm) at 60 cm. The results showed significant differences in accuracy between the conditions; the larger the stimulus, the better the accuracy obtained. It was also shown that these differences were not due to incorrect perception of the stimuli since there was no effect from the size in a perceptual discrimination task. The present work therefore shows that stimulus size has an impact on the performance of an ERP-BCI under RSVP. This finding should be considered by future ERP-BCI proposals aimed at users who need gaze-independent systems.

The influence of stimulus eccentricity on prosaccade outcomes in patients with Alzheimer's Disease dementia at an early stage and amnestic mild cognitive impairment

INTRODUCTION

Prosaccade task is a widely used objective method to evaluate reflexive saccade and visual attention. The study aimed to investigate prosaccade stimulus eccentricity, compare prosaccade parameters in patients with Alzheimer's disease dementia (AD), amnestic mild cognitive impairment (aMCI), and neurotypical adults (NA), and examine the relationship between prosaccade and neuropsychological tests.

METHODS

Thirty patients with AD, 34 with aMCI, and 32 NA were included in the study. Eye movements were recorded with the EyeLink 1000 Plus in the prosaccade task, and this study evaluated cognitive function with comprehensive neuropsychological tests assessing attention, memory, executive function, visuospatial function, and language domains.

RESULTS

The correct saccade rates of patients with AD were significantly lower than NA in the 5^° and 10^° stimulus eccentricities. Patients with AD had significantly longer latencies in the 10° stimulus eccentricity than those with aMCI and NA. Patients with aMCI did not differ in prosaccade performance compared to NA. Prosaccade parameters were significantly correlated with all cognitive domains. As the amplitude of the stimuli increased, the rate of correct saccades decreased, while the express saccade rate, latency, amplitude, and peak velocity increased.

CONCLUSION

Our findings that correct saccade rates and latency may be distinguishing parameters of early AD are promising. This study also found that stimulus eccentricity affects prosaccade measures in AD, MCI, and NA.

Outcome devaluation by specific satiety disrupts sensory-specific Pavlovian-to-instrumental transfer

Reward predictive cues can selectively motivate instrumental behaviors that predict the same rewarding outcomes, an effect known as specific Pavlovian-to-instrumental transfer (PIT). This selective effect is thought to be mediated by a representation of the sensory specific properties of an outcome, that has become associated with both the Pavlovian cue and the instrumental response during initial learning. Specific satiety is a common method of outcome devaluation that reduces an outcome's value but might also lead to the habituation of the outcome's sensory properties. Previous research has demonstrated that specific PIT is insensitive to changes in specific outcome value following taste aversion devaluation, as well as general satiety manipulations, and therefore specific satiety should not disrupt specific PIT by reducing outcome value. The present rodent experiments used a specific satiety devaluation procedure immediately prior to a specific PIT test to show that habituation of these outcome specific sensory representations can disrupt its efficacy as a stimulus and abolish the specific PIT effect. Experiment 1 employed a two-lever choice test to show that a non-devalued stimulus supports specific PIT, whereas a devalued stimulus abolished the specific PIT effect. Experiment 2 replicated this procedure while controlling for response competition by using a single-lever test to confirm that a devalued stimulus abolishes the specific PIT effect. These findings demonstrate that specific satiety can disrupt the ability of an outcome specific representation to support specific PIT. Given previous findings that specific PIT is insensitive to changes in outcome value by general satiety and taste aversion devaluation, this suggests that specific satiety devaluation might disrupt the use of sensory specific outcome representations to guide behavior via a mechanism that is independent of the outcome's current value.

Short-term exposure to heatwave-like temperatures affects learning and memory in bumblebees

Global warming has been identified as a key driver of bee declines around the world. While it is clear that elevated temperatures during the spring and summer months-the principal activity period of many bee species-is a factor in this decline, exactly how temperature affects bee survival is unknown. In vertebrates, there is clear evidence that elevated ambient temperatures impair cognition but whether and how heat affects the cognitive abilities of invertebrates remains unclear. Cognitive skills in bees are essential for their survival as, to supply the hive with nutrition, workers must be able to learn and remember the location of the most rewarding floral resources. Here, we investigate whether temperature-related cognitive impairments could be a driver of bee declines by exploring the effect of short-term increases in ambient temperature on learning and memory. We found that, in comparison to bees that were tested at 25°C (a temperature that they would typically experience in summer), bees that were exposed to 32°C (a temperature that they will becoming increasingly exposed to during heatwave events) were significantly worse at forming an association between a coloured light and a sucrose reward and that their capacity to remember this association after just 1 h was abolished. This study provides novel experimental evidence that even just a few hours of exposure to heatwave-like temperatures can severely impair the cognitive performance of insects. Such temperature-induced cognitive deficits could play an important role in explaining recent and future bee population declines.

Applications of Metal-Organic Frameworks as Drug Delivery Systems

In the last decade, metal organic frameworks (MOFs) have shown great prospective as new drug delivery systems (DDSs) due to their unique properties: these materials exhibit fascinating architectures, surfaces, composition, and a rich chemistry of these compounds. The DSSs allow the release of the active pharmaceutical ingredient to accomplish a desired therapeutic response. Over the past few decades, there has been exponential growth of many new classes of coordination polymers, and MOFs have gained popularity over other identified systems due to their higher biocompatibility and versatile loading capabilities. This review presents and assesses the most recent research, findings, and challenges associated with the use of MOFs as DDSs. Among the most commonly used MOFs for investigated-purpose MOFs, coordination polymers and metal complexes based on synthetic and natural polymers, are well known. Specific attention is given to the stimuli- and multistimuli-responsive MOFs-based DDSs. Of great interest in the COVID-19 pandemic is the use of MOFs for combination therapy and multimodal systems.

Receptive field estimation in large visual neuron assemblies using a super-resolution approach

Computing the spike-triggered average (STA) is a simple method to estimate the sensory neurons' linear receptive fields (RFs). For random, uncorrelated stimuli the STA provides an unbiased RF estimate, but in practice, white noise is not a feasible stimulus as it usually evokes only weak responses. Therefore, for a visual stimulus, it is often used images of randomly modulated blocks of pixels. This solution naturally limits the resolution at which an RF can be obtained. Here we show that this limitation can be overcome by using a simple super-resolution technique. We define a novel type of stimulus, the Shifted White Noise (SWN), by introducing random spatial shifts in the usual stimulus in order to increase the resolution of the measurements. In simulated data we show that the average error using the SWN was 1.7 times smaller than when using the classical stimulus, with successful mapping of 2.3 times more neurons, covering a broader range of RF sizes. Moreover, successful RF mapping was achieved with short recordings of about one minute of activity, more than 10 times more efficient than the classical white noise stimulus. In recordings from mouse retinal ganglion cells with large scale microelectrode arrays, we could map 18 times more RFs covering a broader range of sizes. In summary, here we show that randomly shifting the usual white noise stimulus significantly improves RFs estimation, and requires only short recordings. It is straight forward to extend this method into the time dimension and adapt it to other sensory modalities.

The Escherichia coli two-component signal sensor BarA binds protonated acetate via a conserved hydrophobic-binding pocket

The BarA/UvrY two-component signal transduction system is widely conserved in γ-proteobacteria and provides a link between the metabolic state of the cells and the Csr posttranscriptional regulatory system. In Escherichia coli, the BarA/UvrY system responds to the presence of acetate and other short-chain carboxylic acids by activating transcription of the noncoding RNAs, CsrB and CsrC, which sequester the RNA-binding protein CsrA, a global regulator of gene expression. However, the state of the carboxyl group in the acetate molecule, which serves as the BarA stimulus, and the signal reception site of BarA remain unknown. In this study, we show that the deletion or replacement of the periplasmic domain of BarA and also the substitution of certain hydroxylated and hydrophobic amino acid residues in this region, result in a sensor kinase that remains unresponsive to its physiological stimulus, demonstrating that the periplasmic region of BarA constitutes a functional detector domain. Moreover, we provide evidence that the protonated state of acetate or formate serves as the physiological stimulus of BarA. In addition, modeling of the BarA sensor domain and prediction of the signal-binding site, by blind molecular docking, revealed a calcium channels and chemotaxis receptors domain with a conserved binding pocket, which comprised uncharged polar and hydrophobic amino acid residues. Based on the comparative sequence and phylogenetic analyses, we propose that, at least, two types of BarA orthologues diverged and evolved separately to acquire distinct signal-binding properties, illustrating the wide adaptability of the bacterial sensor kinase proteins.

Dual-Targeting and Stimuli-Triggered Liposomal Drug Delivery in Cancer Treatment

The delivery of chemotherapeutics to solid tumors using smart drug delivery systems (SDDSs) takes advantage of the unique physiology of tumors (i.e., disordered structure, leaky vasculature, abnormal extracellular matrix (ECM), and limited lymphatic drainage) to deliver anticancer drugs with reduced systemic side effects. Liposomes are the most promising of such SDDSs and have been well investigated for cancer therapy. To improve the specificity, bioavailability, and anticancer efficacy of liposomes at the diseased sites, other strategies such as targeting ligands and stimulus-sensitive liposomes have been developed. This review highlights relevant surface functionalization techniques and stimuli-mediated drug release for enhanced delivery of anticancer agents at tumor sites, with a special focus on dual functionalization and design of multistimuli responsive liposomes.

Electrogustometry: Normative data for stimulus duration, tongue site and age decline

OBJECTIVES

Our primary goal was to evaluate the effect of stimulus duration on electrogustometry (EGM) thresholds. Additionally, we sought to evaluate any sex-related influences and compare the above results to those of taste strips.

DESIGN

Electrogustometry thresholds of various stimulus durations (0.5, 1.0, 1.5 and 2.0 seconds) were measured in 212 non-smokers (age range: 10-80 years, divided into eight age-groups) without self-reported gustatory impairment. Furthermore, taste strips chemogustometry measurements in 132 participants were performed.

SETTING

Tertiary referral medical centre.

PARTICIPANTS

212 non-smokers, divided into eight age-groups participated in the study.

MAIN OUTCOME MEASURES

Electrogustometry thresholds and taste strips, duration of EGM stimuli.

RESULTS

Electrogustometry thresholds increased progressively with age and with stimulus duration from 0.5 to 2 seconds. This pattern was consistent in all six anatomic areas, irrespective of sex. In contrast, when using chemogustometry, no age- or sex-related differences were observed.

CONCLUSIONS

Electrogustometry-threshold values increase progressively with age and with stimulus duration. Therefore, we recommend documenting stimulus duration in the future EGM recordings as it may significantly affect EGM amplitude threshold values.

Stimulation action of mefenpyr-diethyl on soybean, wheat, and signal grass plants

Mefenpyr-diethyl is a safener used for protection of cereal plants under applications of ACCase and ALS inhibitor herbicides. Current studies are describing safeners using a new approach, relating these products to stimulation action on plants. The objective of this work was to evaluate the stimulation action of mefenpyr-diethyl on soybean, wheat, and signal grass plants. The experiment was conducted in a greenhouse, under a completely randomized design, with four replications, in two seasons. Mefenpyr-diethyl (50 g a.i. ha-1) was applied on soybean plants (at V4 stage), and wheat and signal grass plants (both with 15 cm height). The variables evaluated were plant height, dry matter, and lipid content of the three species, and number of tillers of wheat and signal grass plants. The application of mefenpyr-diethyl in the first season increased the number of tillers of wheat and height of soybean plants. The soybean presented 24 and 14% more dry matter than the control in the first and second season, respectively, and 0.5% more lipid content in plants treated with mefenpyr-diethyl. These results show the stimulation action of mefenpyr-diethyl on wheat and soybean plants, denoting its potential for growth promotion and indicating the need for studies with this approach. No effect was found for the signal grass plants.

Nanomedicine for the Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that results in severe inflammatory microenvironments in the joint tissues. In clinics, disease-modifying antirheumatic drugs (DMARDs) are generally prescribed to patients with RA, but their long-term use often shows toxicity in some organs such as the gastrointestinal system, skin, and kidneys and immunosuppression-mediated infection. Nanomedicine has emerged as a new therapeutic strategy to efficiently localize the drugs in inflamed joints for the treatment of RA. In this Review, we introduce recent research in the area of nanomedicine for the treatment of RA and discuss how the nanomedicine can be used to deliver therapeutic agents to the inflamed joints and manage the progression of RA, particularly focusing on targeted delivery, controlled drug release, and immune modulation.

Modulation of experimental facial pain via somatosensory stimuli targeting sensations of different valence

BACKGROUND

Knowledge of pain modulation from oro-facial somatosensory stimuli with different valence (pleasant-unpleasant) is limited.

OBJECTIVES

To investigate (a) the modulatory effects of painful, pleasant and unpleasant somatosensory stimuli on two models of experimental facial pain, (b) whether modulation could be changed by blocking peripheral nerves via application of a local anaesthetic, EMLA, or blocking endogenous opioid receptors via naltrexone and (c) whether pain ratings were significantly correlated with participant psychological profiles.

METHODS

Thirty-eight healthy women received experimental facial skin burning pain or jaw myalgia for four randomised sessions on different days. The painful region was stimulated with mechanical or thermal painful, pleasant, unpleasant and control stimuli, with ratings recorded before and during stimulation. Sessions differed in pre-treatment: EMLA/naltrexone/placebo tablet/cream.

RESULTS

Significant effects of thermal or mechanical stimuli (P < .017), but not session (P > .102), were found on pain ratings for both models. In myalgia, painful cold resulted in a greater reduction in pain ratings than unpleasant cold, pleasant cold, control and pleasant warmth (P < .004). Decreases in pain ratings from painful, unpleasant and pleasant mechanical stimuli were greater than control (P < .002). In burning pain, painful cold resulted in a greater reduction in pain ratings than all but one of the other thermal stimuli (P < .033). The pleasant mechanical stimulus reduced pain ratings more than all other mechanical stimuli (P ≤ .003). There were no significant correlations between pain and psychometrics.

CONCLUSION

Valence-targeted thermal and mechanical stimuli modulated experimental myalgia and skin burning pain (P < .017). Partially blocking peripheral afferents or opioid receptors did not affect modulation.

The robustness of eye-mouth index as an eye-tracking metric of social attention in toddlers

Eye-tracking research on social attention in infants and toddlers has included heterogeneous stimuli and analysis techniques. This allows measurement of looking to inner facial features under diverse conditions but restricts across-study comparisons. Eye-mouth index (EMI) is a measure of relative preference for looking to the eyes or mouth, independent of time spent attending to the face. The current study assessed whether EMI was more robust to differences in stimulus type than percent dwell time (PDT) toward the eyes, mouth, and face. Participants were typically developing toddlers aged 18 to 30 months (N = 58). Stimuli were dynamic videos with single and multiple actors. It was hypothesized that stimulus type would affect PDT to the face, eyes, and mouth, but not EMI. Generalized estimating equations demonstrated that all measures including EMI were influenced by stimulus type. Nevertheless, planned contrasts suggested that EMI was more robust than PDT when comparing heterogeneous stimuli. EMI may allow for a more robust comparison of social attention to inner facial features across eye-tracking studies.

The effect of nacre extract on cord blood-derived endothelial progenitor cells: A natural stimulus to promote angiogenesis?

Angiogenesis is a critical parameter to consider for the development of tissue-engineered bone substitutes. The challenge is to promote sufficient vascularization in the bone substitute to prevent cell death and to allow its efficient integration. The capacity of nacre extract to restore the osteogenic activity of osteoarthritis osteoblasts has already been demonstrated. However, their angiogenic potential on endothelial progenitor cells (EPCs) was not yet explored. Therefore, the current study aimed at investigating if nacreous molecules affect EPC behavior. The gene and protein expression levels of endothelial cell (EC)-specific markers were determined in EPCs cultivated in presence of a nacre extract (ethanol soluble matrix [ESM] at two concentrations: 100 μg/mL and 200 μg/mL (respectively abbreviated ESM100 and ESM200)). Cell functionality was explored by proangiogenic factors production and in vitro tube formation assay. ESM200 increased the expression of some EC-specific genes. The in vitro tube formation assay demonstrated that ESM200 stimulated tubulogenesis affecting angiogenic parameters. We demonstrated that a stimulation with 200 μg/mL of ESM increased angiogenesis key elements. This in vitro study strongly highlights the proangiogenic effect of ESM. Due to its osteogenic properties, previously demonstrated, ESM could constitute the key element to develop an ideal prevascularized bone substitute. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2019.

Investigation of the Pattern of the Hemodynamic Response as Measured by Functional Near-Infrared Spectroscopy (fNIRS) Studies in Newborns, Less Than a Month Old: A Systematic Review

It has been 20 years since functional near-infrared spectroscopy (fNIRS) was first used to investigate the evoked hemodynamic response to a stimulus in newborns. The hemodynamic response to functional activation is well-established in adults, with an observed increase in concentration change of oxygenated hemoglobin (Δ[HbO2]) and decrease in deoxygenated hemoglobin (Δ[HHb]). However, functional studies in newborns have revealed a mixed response, particularly with Δ[HHb] where an inconsistent change in direction is observed. The reason for this heterogeneity is unknown, with potential explanations arising from differing physiology in the developing brain, or differences in instrumentation or methodology. The aim of this review is to collate the findings from studies that have employed fNIRS to monitor cerebral hemodynamics in term newborn infants aged 1 day-1 month. A total of 46 eligible studies were identified; some studies investigated more than one stimulus type, resulting in a total of 51 reported results. The NIRS parameters reported varied across studies with 50/51 cases reporting Δ[HbO2], 39/51 reporting Δ[HHb], and 13/51 reporting total hemoglobin concentration Δ[HbT] (Δ[HbO2] + Δ[HHb]). However, of the 39 cases reporting Δ[HHb] in graphs or tables, only 24 studies explicitly discussed the response (i.e., direction of change) of this variable. In the studies where the fNIRS responses were discussed, 46/51 cases observed an increase in Δ[HbO2], 7/51 observed an increase or varied Δ[HHb], and 2/51 reported a varied or negative Δ[HbT]. An increase in Δ[HbO2] and decrease or no change in Δ[HHb] was observed in 15 studies. By reviewing this body of literature, we have identified that the majority of research articles reported an increase in Δ[HbO2] across various functional tasks and did not report the response of Δ[HHb]. Confirming the normal, healthy hemodynamic response in newborns will allow identification of unhealthy patterns and their association to normal neurodevelopment.

Hormetic effects of glyphosate on plants

As all herbicides act on pathways or processes crucial to plants, in an inhibitory or stimulatory way, low rates of any herbicide might be used to modulate plant growth, development, or plant composition. Glyphosate is the most used herbicide in the world, and very low rates of this herbicide can stimulate plant growth, an effect called hormesis. Several studies have shown that glyphosate applications at low rates can increase plant growth, induce shikimic acid accumulation, increase photosynthesis and stomatal opening, increase seed production, and shorten the plant life cycle. Low rates of glyphosate applied to leaves have been reported to cause one or more of these effects in an expanding group of species. Under field conditions, pesticide rates are not uniform, causing some target organisms to receive rates that are low enough to cause hormesis. Until the present, low rates of glyphosate have not been recommended as a growth stimulant for crops, because the hormetic dose can vary considerably, depending on many factors. The objective of the present review is to summarize and analyze existing information about the hormetic effects of glyphosate on plants, thus contributing to understanding how glyphosate hormesis takes place and evaluating the potential use of glyphosate to stimulate plant growth. © 2017 Society of Chemical Industry.

Children's Recognition of Emotional Facial Expressions Through Photographs and Drawings

The author's purpose was to examine children's recognition of emotional facial expressions, by comparing two types of stimulus: photographs and drawings. The author aimed to investigate whether drawings could be considered as a more evocative material than photographs, as a function of age and emotion. Five- and 7-year-old children were presented with photographs and drawings displaying facial expressions of 4 basic emotions (i.e., happiness, sadness, anger, and fear) and were asked to perform a matching task by pointing to the face corresponding to the target emotion labeled by the experimenter. The photographs we used were selected from the Radboud Faces Database and the drawings were designed on the basis of both the facial components involved in the expression of these emotions and the graphic cues children tend to use when asked to depict these emotions in their own drawings. Our results show that drawings are better recognized than photographs, for sadness, anger, and fear (with no difference for happiness, due to a ceiling effect). And that the difference between the 2 types of stimuli tends to be more important for 5-year-olds compared to 7-year-olds. These results are discussed in view of their implications, both for future research and for practical application.

Extinction of alcohol seeking is enhanced by compound extinction and the noradrenaline reuptake inhibitor atomoxetine

Alcohol-related stimuli can trigger relapse of alcohol-seeking behaviors even after extended periods of abstinence. Extinction of such stimuli provides a means for reducing their impact on relapse. However, the expression of extinction can be disrupted by exposure to the previous reinforcer as well as the simple passage of time. We investigated whether augmentation of prediction error or of noradrenaline neurotransmission by the reuptake inhibitor atomoxetine would enhance long-term extinction of alcohol-seeking behavior. Rats received Pavlovian conditioning of multiple stimuli signaling the delivery of an alcohol reward before individual extinction was given to each of these stimuli. Further extinction was then given to a target stimulus presented in compound with another alcohol-predictive stimulus intended to augment prediction error (Experiment 1) or after a systemic injection of atomoxetine (1.0 mg/kg; Experiment 2). Experiment 3 examined whether the compound stimulus effect relied on noradrenergic activity by testing the effects of the β-adrenergic antagonist propranolol, given prior to compound stimulus trials. Long-term retention of extinction learning was assessed a week later. Compound stimulus presentations enhanced long-term extinction as the stimulus extinguished in compound elicited less responding than a stimulus receiving equal extinction alone when tested a week later. This effect was mimicked by atomoxetine and blocked by propranolol given during extinction training. Thus, extinction of alcohol-seeking behavior can be improved by extinguishing multiple alcohol-predictive stimuli or enhancing noradrenaline neurotransmission during extinction training. Both behavioral and neurobiological processes could be exploited to enhance the outcome of extinction-based treatments for alcohol use disorders.

Contexts Paired with Junk Food Impair Goal-Directed Behavior in Rats: Implications for Decision Making in Obesogenic Environments

The high prevalence of obesity and related metabolic diseases calls for greater understanding of the factors that drive excess energy intake. Calorie-dense palatable foods are readily available and often are paired with highly salient environmental cues. These cues can trigger food-seeking and consumption in the absence of hunger. Here we examined the effects of palatable food-paired environmental cues on control of instrumental food-seeking behavior. In Experiment 1, adult male rats received exposures to one context containing three “junk” foods (JFs context) and another containing chow (Chow context). Next, rats were food-deprived and trained to perform instrumental responses (lever-press) for two novel food rewards in a third, distinct context. Contextual influences on flexible control of food-seeking behavior were then assessed by outcome devaluation tests held in the JF, chow and training contexts. Devaluation was achieved using specific satiety and test order was counterbalanced. Rats exhibited goal-directed control over behavior when tested in the training and chow-paired contexts. Notably, performance was habitual (insensitive to devaluation) when tested in the JF context. In Experiment 2 we tested whether the impairment found in the JF context could be ameliorated by the presentation of a discrete auditory cue paired with the chow context, relative to a second cue paired with the JF context. Consistent with the results of Experiment 1, the devaluation effect was not significant when rats were tested in the JF context with the JF cue. However, presenting the chow cue increased the impact of the devaluation treatment leading to a robust devaluation effect. Further tests confirmed that performance in the chow context was goal-directed and that sensory-specific satiety in the JF context was intact. These results show that environments paired with palatable foods can impair goal-directed control over food-seeking behavior, but that this deficit was improved by a cue paired with chow. This has promising implications for assisting individuals in controlling their eating behavior in environments designed to dysregulate it.

Dual-Triggered and Thermally Reconfigurable Shape Memory Graphene-Vitrimer Composites

Conventional thermoset shape memory polymers can maintain a stable permanent shape, but the intrinsically chemical cross-linking leads to shape that cannot be altered. In this paper, we prepared shape memory graphene-vitrimer composites whose shape can be randomly changed via dynamic covalent transesterification reaction. Consecutive shape memory cycles indicate stable shape memory with undetected strain shift and constant shape fixity and recovery values (Rf > 99%, Rr > 98%). Quantitative characterization of shape reconfiguration by dynamic mechanical thermal analysis (DMA) shows prime reconfigurable behavior with shape retention ratio of 100%. Thus, the arbitrary 2D or 3D newly permanent shape can be easily obtained from a simple plain sample by facile thermal treatment at 200 °C above transesterification temperature (Tv). Besides, it is found that graphene-vitrimers show a ductile fracture in tensile test with a large breaking strain and classical yield phenomenon because of the well-dispersed graphene sheets in the vitrimer that endow effective stress transfer. As the graphene loading increases from 0% to 1%, the yield strength and breaking stain increase from 12.0 MPa and 6% to 22.9 MPa and 44%, respectively. In addition, graphene also serves as energy convertor to convert near-infrared (NIR) irradiation into thermal energy to induce a helix shape sample that is recovered totally within 80 s sequent NIR irradiation. These dual-triggered and reconfigurable shape memory graphene-vitrimers are expected to significantly simplify processing of complex shape and broaden the applications of shape memory polymers.

Nucleus accumbens core and shell are differentially involved in general and outcome-specific forms of Pavlovian-instrumental transfer with alcohol and sucrose rewards

Alcohol-associated stimuli contribute to relapse risk. Therefore, understanding the behavioural and neural mechanisms underlying the ability of such stimuli to promote alcohol-seeking is important for developing effective treatments for alcohol-use disorders. The Pavlovian-instrumental transfer (PIT) paradigm can be used to study the influence of Pavlovian cues on independently-trained instrumental responses earning reward. The effects can be either general, increasing the vigour of reward-related behaviours, or specific to responses that earn a common outcome. These different forms of PIT are mediated by distinct neural circuits involving the nucleus accumbens (NAC) core and shell, respectively. Here we examined the effects of pharmacological inactivation of either the NAC core or shell on PIT generated by alcohol-predictive and sucrose-predictive stimuli in rats. We found that presentations of a stimulus predicting sucrose enhanced responding for sucrose but not alcohol, suggesting an outcome-specific effect. In contrast, presentations of an alcohol-predictive stimulus enhanced responding for both alcohol and sucrose, suggesting a generally arousing effect. Inactivation of the NAC core reduced PIT and, in particular, the effect of the alcohol stimulus. Inactivation of the NAC shell reduced the specificity of the stimulus effects but left the ability of the stimuli to non-specifically invigorate responding intact, consistent with a role in mediating the specificity of PIT. Together, these results suggest that the NAC core plays a particularly important role in mediating the influence of alcohol-predictive cues on reward-seeking behaviours.

Hospital Clowning as Play Stimulus in Healthcare

A serious illness, a chronic medical condition or a hospital bed should not deny any child her/his basic right to play, a right essential for children’s development and general wellbeing. In fact, it is in these frightening and anxious moments that play and the stimulus that it provides can help the most. This article will focus on the impacts and benefits of professional hospital clowning for the wellbeing and recovery process of ill and hospitalized children. Our experience has shown that through interactive play and humor, “clowndoctors” can create an enabling and supportive environment that facilitates children’s adaptation to the hospital setting and improves their acceptance of medical procedures and staff. While moving from bedside to bedside, RED NOSES clowndoctors encourage children’s active participation and support their natural instinct to play, fully including them in the interaction, if the children wish to do so. Therefore, clowndoctor performances offer ill children much needed stimulus, self-confidence and courage, elements fundamental to reducing their vulnerability. In this piece, a special emphasis will be put on the various approaches used by RED NOSES clowndoctors to bond and reach out to children suffering from different medical conditions.

Generalization of fear-potentiated startle in the presence of auditory cues: a parametric analysis

Intense fear responses observed in trauma-, stressor-, and anxiety-related disorders can be elicited by a wide range of stimuli similar to those that were present during the traumatic event. The present study investigated the experimental utility of fear-potentiated startle paradigms to study this phenomenon, known as stimulus generalization, in healthy volunteers. Fear-potentiated startle refers to a relative increase in the acoustic startle response to a previously neutral stimulus that has been paired with an aversive stimulus. Specifically, in Experiment 1 an auditory pure tone (500 Hz) was used as the conditioned stimulus (CS+) and was reinforced with an unconditioned stimulus (US), an airblast to the larynx. A distinct tone (4000 Hz) was used as the nonreinforced stimulus (CS−) and was never paired with an airblast. Twenty-four hours later subjects underwent Re-training followed by a Generalization test, during which subjects were exposed to a range of generalization stimuli (GS) (250, 1000, 2000, 4000, 8000 Hz). In order to further examine the point at which fear no longer generalizes, a follow-up experiment (Experiment 2) was performed where a 4000 Hz pure tone was used as the CS+, and during the Generalization test, 2000 and 8000 Hz were used as GS. In both Experiment 1 and 2 there was significant discrimination in US expectancy responses on all stimuli during the Generalization Test, indicating the stimuli were perceptually distinct. In Experiment 1, participants showed similar levels of fear-potentiated startle to the GS that were adjacent to the CS+, and discriminated between stimuli that were 2 or more degrees from the CS+. Experiment 2 demonstrated no fear-potentiated startle generalization. The current study is the first to use auditory cues to test generalization of conditioned fear responses; such cues may be especially relevant to combat posttraumatic stress disorder (PTSD) where much of the traumatic exposure may involve sounds.

Myopia induced by flickering light in guinea pigs: a detailed assessment on susceptibility of different frequencies

AIM

To investigate the effectiveness and feasibility of inducing myopia in guinea pigs by flickering light (FL) stimulation with different frequencies.

METHODS

Seventy 2-week-old guinea pigs were randomly assigned to six groups: five FL groups and a control group (n=12 for each). Animals in the five FL groups were raised under 500lx illumination with a duty diurnal cycle of 50% at a flash rate of 5, 1, 0.5, 0.25 and 0.1Hz respectively. Those in the control group were reared under steady 250lx illumination. Refraction, axial length, and radius of curvature were measured before and at 2, 4, 6, 8, 10 and 12 weeks after treatment. At week 12, the eyeballs were taken out and three ocular dimensions and dry weight of sclera were measured.

RESULTS

A myopic shift and axial eye length increase developed in the five FL groups. Stimulation at 0.5Hz caused greater changes in myopic shift, axial elongation, eyeball dimension, and dry weight of sclera than stimulation at other frequencies. Compared with controls, eyes in 0.5Hz group were approximately -5.5±1.5D more myopic with increase in horizontal, vertical, axial dimensions by 0.89±0.3mm, 0.69±0.2mm, 1.12±0.2mm respectively and with increase in dry weight of sclera by 0.44mg.

CONCLUSION

Chronic exposure to periodic illumination at temporal frequency is attended by development of excessive ocular enlargement and myopic refractive error. Emmetropization could be disrupted differently by frequency alteration.

Auditory stimuli elicit hippocampal neuronal responses during sleep

To investigate how hippocampal neurons code behaviorally salient stimuli, we recorded from neurons in the CA1 region of hippocampus in rats while they learned to associate the presence of sound with water reward. Rats learned to alternate between two reward ports at which, in 50% of the trials, sound stimuli were presented followed by water reward after a 3-s delay. Sound at the water port predicted subsequent reward delivery in 100% of the trials and the absence of sound predicted reward omission. During this task, 40% of recorded neurons fired differently according to which of the two reward ports the rat was visiting. A smaller fraction of neurons demonstrated onset response to sound/nosepoke (19%) and reward delivery (24%). When the sounds were played during passive wakefulness, 8% of neurons responded with short latency onset responses; 25% of neurons responded to sounds when they were played during sleep. During sleep the short-latency responses in hippocampus are intermingled with long lasting responses which in the current experiment could last for 1-2 s. Based on the current findings and the results of previous experiments we described the existence of two types of hippocampal neuronal responses to sounds: sound-onset responses with very short latency and longer-lasting sound-specific responses that are likely to be present when the animal is actively engaged in the task.

Electroconvulsive therapy stimulus parameters: rethinking dosage

In this article, we review the parameters that define the electroconvulsive therapy (ECT) electrical stimulus and discuss their biophysical roles. We also present the summary metrics of charge and energy that are conventionally used to describe the dose of ECT and the rules commonly deployed to individualize the dose for each patient. We then highlight the limitations of these summary metrics and dosing rules in that they do not adequately capture the roles of the distinct stimulus parameters. Specifically, there is strong theoretical and empirical evidence that stimulus parameters (pulse amplitude, shape, and width, and train frequency, directionality, polarity, and duration) exert unique neurobiological effects that are important for understanding ECT outcomes. Consideration of the distinct stimulus parameters, in conjunction with electrode placement, is central to further optimization of ECT dosing paradigms to improve the risk-benefit ratio. Indeed, manipulation of specific parameters, such as reduction of pulse width and increase in number of pulses, has already resulted in dramatic reduction of adverse effects, while maintaining efficacy. Furthermore, the manipulation of other parameters, such as current amplitude, which are commonly held at fixed, high values, might be productively examined as additional means of targeting and individualizing the stimulus, potentially reducing adverse effects. We recommend that ECT dose be defined using all stimulus parameters rather than a summary metric. All stimulus parameters should be noted in treatment records and published reports. To enable research on optimization of dosing paradigms, we suggest that ECT devices provide capabilities to adjust and display all stimulus parameters.

Updating working memory for words: a PET activation study

A PET study of 10 normal individuals was carried out to investigate the cerebral regions involved in the controlled updating of verbal working memory. Subjects viewed single concrete words on a computer monitor and detected occasional target words in an attended color. In the activating condition, a target was defined as a word that was identical to the previous word presented in the attended color. In the control condition, the target was a predesignated word. The same word lists, target probabilities, and target response demands were used for both conditions, with interword intervals constrained to ensure equivalence in the demand for target rehearsal. A comparison of the conditions found bilateral activation of dorsolateral prefrontal (middle frontal gyrus; MFG) and inferior parietal (supramarginal gyrus; SMG) cortical regions. Activation of the MFG is taken to reflect executive control by prefrontal regions over the working memory updating process linking posterior representations of the anticipated target stimulus to anterior representations of the planned response. It is proposed that the updating of the stimulus link is mediated via connections between the MFG and SMG. The role of the SMG as an amodal region binding the various modal representations in posterior association cortex of the word being retained in working memory is considered and reviewed. It is suggested that the combined activation of these regions is related to the executive control of goal-setting in planned behavior.