Series Of Stimuli Research Articles

Analysis of abiotic and biotic stress-induced Ca2+ transients in the crop species Solanum tuberosum.

Secondary messengers, such as calcium ions (Ca2+), are integral parts of a system that transduces environmental stimuli into appropriate cellular responses. Different abiotic and biotic stresses as well as developmental processes trigger temporal increases in cytosolic free Ca2+ levels by an influx from external and internal stores. Stimulus-specificity is obtained by a certain amplitude, duration, oscillation and localisation of the response. Most knowledge on stress-specific Ca2+ transient, called calcium signatures, has been gained in the model plant Arabidopsis thaliana, while reports about stress-related Ca2+ signalling in crop plants are comparatively scarce. In this study, we introduced the Ca2+ biosensor apoaequorin into potato (Solanum tuberosum, Lcv.Désirée). We observed dose-dependent calcium signatures in response to a series of stress stimuli, including H2O2, NaCl, mannitol and pathogen-associated molecular patterns (PAMPs) with stimuli-specific kinetics. Direct comparison with Arabidopsis revealed differences in the kinetics and amplitude of Ca2+ transients between both species, implying species-specific sensitivity for different stress conditions. The potato line generated in this work provides a useful tool for further investigations on stress-induced signalling pathways, which could contribute to the generation of novel, stress-tolerant potato varieties.

Encoding colors and tones into working memory concurrently: A developmental investigation.

Working memory serves as a means to accumulate information and reorganize it. Researchers have long assumed that the natural organization of information is one stream at a time. This logic leads to the expectation that, when two different series of stimuli are to be remembered, performance should be superior if the series are presented one before the other in succession, rather than concurrently. Moreover, different accounts of attentional limits lead to different expectations for the change in the ability to encode two sets across age groups in childhood. Testing children from first grade (6-7years) to adulthood, we presented sequences of colored objects and tones in succession or concurrently (with one color accompanying an unrelated tone) and found that performance was equally good no matter which presentation method was used. The results for both presentation methods closely matched the intricate pattern of development observed by Cowan etal. (2018), who used successive presentation only. We found marked developmental improvement in the ability to retain materials in each modality without an increasing cost of attention-sharing between modalities. Humans at least from the elementary school years through young adulthood thus display an ability to accommodate and organize two concurrent streams of information. RESEARCH HIGHLIGHTS: Memory for stimuli from multiple modalities is relevant to school performance and learning; here we investigate how attention is shared between remembering colors and tones. Participants received four colors and/or four tones for subsequent recognition on a trial, with dual modalities presented successively (0.5s per stimulus) or concurrently (0.5s per pair). Successive versus concurrent presentation had little effect on recognition, and the marked increase in memory performance with age did not come from dividing attention during encoding or maintenance. Children as young as first grade thus can encode and organize for later recognition colors and concurrently-presented, but unrelated, tones.

Adapting Minds: Exploring Cognition to Threatened Stimuli in the Post-COVID-19 Landscape Comparing Old and New Concerns about Pandemic.

The global population has been significantly affected by the pandemic in terms of physical and mental health. According to transactional theory, individuals have undergone an adaptation process influenced by cognitive control abilities. Emotional responses to COVID-19-related stimuli may interfere with top-down attentional processes, thereby hindering adaptation. This study aimed to investigate the impact of COVID-19-related stimuli on attentional processing and to determine whether psychological factors could modulate these effects. A sample of 96 healthy undergraduate students participated in an emotional Stroop task in which they were presented with a series of stimuli, including both neutral and negative COVID-19-related as well as non-COVID-19 stimuli. COVID-19-related PTSD, as an index of distress (PTSS), and trait anxiety were evaluated. Results showed that participants were more accurate in identifying COVID-19-related stimuli compared to non-COVID-19 stimuli. Being female and having higher retrospective PTSS scores related to COVID-19 were predictive of faster reaction times for both neutral and negative COVID-19-related stimuli. This heightened attentional bias toward COVID-19-related stimuli suggests that individuals may be more sensitive to stimuli associated with the pandemic. The results suggest that the association between COVID-19 stimuli and attentional biases extends beyond emotional valence, being retrospectively influenced by mental health, suggesting potential pathways to future mental health challenges.

Serial dependence: A matter of memory load

In serial dependence, perceptual decisions are biased towards stimuli encountered in the recent past. Here, we investigate whether and how serial dependence is affected by the availability of visual working memory (VWM) resources. In two experiments, participants reproduced the orientation of a series of stimuli. On alternating trials, we included an additional VWM task with randomly varying levels of load. Serial dependence was not only affected by the additional load task but also clearly modulated by the level of load: a high load in the previous trial reduced serial dependence while a high load in the present increased it. These results were independent of the effects of VWM load on the precision of reproduction responses. Our findings provide new insights into the mechanisms that may regulate serial dependence, revealing its intimate link with VWM resources. Significance statementOur perception, thoughts, and behavior are continuously influenced by recent events. For instance, the way we process and understand current visual information depends on what we have seen in the preceding seconds, a phenomenon known as serial dependence. The precise mechanisms and factors involved in serial dependence are still unclear. Here, we demonstrated that working memory resources are a crucial component. Specifically, when we are currently experiencing a heavy memory load, the influence of prior stimuli becomes stronger. Conversely, when prior stimuli were shown under a high memory load, their influence was reduced. These findings highlight the importance of working memory resources in shaping our interpretation of the present based on the recent past.

Dissecting signal transduction pathways that regulate cardiomyocyte proliferation

Abstract Funding Acknowledgements None. Introduction During cardiac development, the Notch, Hippo, and Wnt/β-catenin signalling pathways play a crucial role in the tuning of cardiomyocyte proliferation. The individual engagement of each of these pathways during the early postnatal life, however, is still unclear. Purpose We wanted to develop a method to visualize over time, both in vitro and in vivo, the topography of activation of the Notch, Wnt/β-catenin, and Hippo pathways and their crosstalk upon cardiomyocyte treatment with a series of pro-proliferative stimuli. Methods We obtained Adeno-Associated Virus (AAV) constructs expressing distinct fluorescent proteins (ECFP, GFP, mCherry, DsRed) under the control of promoters that are specifically activated downstream of the signalling cascades of interest (a synthetic promoter consisting of 12 CSL binding sites for Notch1, a synthetic promoter consisting of 8 TEAD binding sites for YAP, and a synthetic promoter containing 7 TCF/LEF1 binding sites for β-catenin). Results First, by high content microscopy we followed the time of the activation of the AAV vectors coding for fluorescent reporters, either alone or in combination. We observed that a crosstalk exists between Yap and Notch signalling in proliferating cardiomyocytes, as detected by the activation of their respective fluorescent reporters. We confirmed our data by gene expression analysis and co-immunoprecipitation using specific antibodies in fractionated cardiomyocyte extracts. Next, we observe that miR-1825, miR-199a-3p, and miR-590-3p – three pro-regenerative miRNAs in cardiomyocytes– specifically activate both Yap and Notch signalling. Finally we characterized the reporter systems in vivo, to dissect the intracellular signalling pathways that are active in the first week of postnatal life. Beta-catenin signalling was quite undetectable in any of the conditions tested. In contrast, both Notch and Yap showed significant activation, consistent with their role in regulating early postnatal cardiomyocyte proliferation. Conclusions The developed AAV-fluorescent reporters allow to efficiently and specifically visualize the pro-proliferative activation of Notch and Yap signalling both in vitro and in vivo. The results obtained are supportive of a crosstalk existing between Notch and Yap pathways in proliferating cardiomyocytes.

Establishing the relationship between subjective perception and neural responses: Insights from correlation analysis and representational similarity analysis

Exploring the relationship between sensory perception and brain responses holds important theoretical and clinical implications. However, commonly used methodologies like correlation analysis performed either intra- or inter- individually often yield inconsistent results across studies, limiting their generalizability. Representational similarity analysis (RSA), a method that assesses the perception-response relationship by calculating the correlation between behavioral and neural patterns, may offer a fresh perspective to reveal novel findings. Here, we delivered a series of graded sensory stimuli of four modalities (i.e., nociceptive somatosensory, non-nociceptive somatosensory, visual, and auditory) to/near the left or right hand of 107 healthy subjects and collected their single-trial perceptual ratings and electroencephalographic (EEG) responses. We examined the relationship between sensory perception and brain responses using within- and between-subject correlation analysis and RSA, and assessed their stability across different numbers of subjects and trials. We found that within-subject and between-subject correlations yielded distinct results: within-subject correlation revealed strong and reliable correlations between perceptual ratings and most brain responses, while between-subject correlation showed weak correlations that were vulnerable to the change of subject number. In addition to verifying the correlation results, RSA revealed some novel findings, i.e., correlations between behavioral and neural patterns were observed in some additional neural responses, such as “γ-ERS” in the visual modality. RSA results were sensitive to the trial number, but not to the subject number, suggesting that consistent results could be obtained for studies with relatively small sample sizes. In conclusion, our study provides a novel perspective on establishing the relationship between behavior and brain activity, emphasizing that RSA holds promise as a method for exploring this pattern relationship in future research.

Electrodermal and central measures of the tonic orienting reflex (OR)

Sokolov described both phasic and tonic aspects of the Orienting Reflex (OR), but subsequent research and theory development has focussed primarily on the phasic OR at the expense of the tonic OR. The present study used prestimulus skin conductance level (SCL) during a dishabituation paradigm to model the tonic OR, examining its amplitude patterning over repeated standard stimulus presentations and a change stimulus. We expected sensitisation (increased amplitude) following the initial and change trials, and habituation (decrement) over the intervening trials. Prestimulus EEG alpha level was explored as a potential central measure of the tonic OR (as an inverse correlate), examining its pattern over stimulus repetition and change in relation to the SCL model. We presented a habituation series of innocuous auditory stimuli to two groups (each N = 20) at different ISIs (Long 13–15 s and Short 5–7 s) and recorded electrodermal and EEG data during two counterbalanced conditions; Indifferent: no task requirements; Significant: silent counting. Across groups and conditions, prestimulus SCLs and alpha amplitudes generally showed the expected trials patterns, confirming our main hypotheses. Findings have important implications for including the assessment of Sokolov's tonic OR in modelling central and autonomic nervous system interactions of fundamental attention and learning processes.

Tracking the habituation of the event-related EEG potential in automatic change detection using an auditory two-tone oddball paradigm.

The mismatch negativity and the P3a of the event-related EEG potential reflect the electrocortical response to a deviant stimulus in a series of stimuli. Although both components have been investigated in various paradigms, these paradigms usually incorporate many repetitions of the same deviant, thus leaving open whether both components vary as a function of the deviant's position in a series of deviant stimuli-i.e. whether they are subject to qualitative/quantitative habituation from one instantiation of a deviant to the next. This is so because the detection of mismatch negativity/P3a in the event-related EEG potential requires an averaging over dozens or hundreds of stimuli, i.e. over many instantiations of the deviant per participant. The present study addresses this research gap. We used a two-tone oddball paradigm implementing only a small number of (deviant) stimuli per participant, but applying it to a large number of participants (n> 230). Our data show that the mismatch negativity amplitude exhibits no decrease as a function of the deviant's position in a series of (standard and) deviant stimuli. Importantly, only after the very first deviant stimulus, a distinct P3a could be detected, indicative of an orienting reaction and an attention shift, and thus documenting a dissociation of mismatch negativity and P3a.

Continuous Rotation Group Equivariant Network Inspired by Neural Population Coding

Neural population coding can represent continuous information by neurons with a series of discrete preferred stimuli, and we find that the bell-shaped tuning curve plays an important role in this mechanism. Inspired by this, we incorporate a bell-shaped tuning curve into the discrete group convolution to achieve continuous group equivariance. Simply, we modulate group convolution kernels by Gauss functions to obtain bell-shaped tuning curves. Benefiting from the modulation, kernels also gain smooth gradients on geometric dimensions (e.g., location dimension and orientation dimension). It allows us to generate group convolution kernels from sparse weights with learnable geometric parameters, which can achieve both competitive performances and parameter efficiencies. Furthermore, we quantitatively prove that discrete group convolutions with proper tuning curves (bigger than 1x sampling step) can achieve continuous equivariance. Experimental results show that 1) our approach achieves very competitive performances on MNIST-rot with at least 75% fewer parameters compared with previous SOTA methods, which is efficient in parameter; 2) Especially with small sample sizes, our approach exhibits more pronounced performance improvements (up to 24%); 3) It also has excellent rotation generalization ability on various datasets such as MNIST, CIFAR, and ImageNet with both plain and ResNet architectures.

Non-coding RNAs as therapeutic targets and biomarkers in ischaemic heart disease.

The adult heart is a complex, multicellular organ that is subjected to a series of regulatory stimuli and circuits and has poor reparative potential. Despite progress in our understanding of disease mechanisms and in the quality of health care, ischaemic heart disease remains the leading cause of death globally, owing to adverse cardiac remodelling, leading to ischaemic cardiomyopathy and heart failure. Therapeutic targets are urgently required for the protection and repair of the ischaemic heart. Moreover, personalized clinical biomarkers are necessary for clinical diagnosis, medical management and to inform the individual response to treatment. Non-coding RNAs (ncRNAs) deeply influence cardiovascular functions and contribute to communication between cells in the cardiac microenvironment and between the heart and other organs. As such, ncRNAs are candidates for translation into clinical practice. However, ncRNA biology has not yet been completely deciphered, given that classes and modes of action have emerged only in the past 5 years. In this Review, we discuss the latest discoveries from basic research on ncRNAs and highlight both the clinical value and the challenges underscoring the translation of these molecules as biomarkers and therapeutic regulators of the processes contributing to the initiation, progression and potentially the prevention or resolution of ischaemic heart disease and heart failure.

Cardiac and neurobehavioral impairments in three phylogenetically distant aquatic model organisms exposed to environmentally relevant concentrations of boscalid

Boscalid (2-Chloro-N-(4′-chlorobiphenyl-2-yl) nicotinamide), a pyridine carboxamide fungicide, is an inhibitor of the complex II of the respiration chain in fungal mitochondria. As boscalid is only moderately toxic for aquatic organisms (LC50 > 1–10 mg/L), current environmental levels of this compound in aquatic ecosystems, in the range of ng/L-μg/L, are considered safe for aquatic organisms. In this study, we have exposed zebrafish (Danio rerio), Japanese medaka (Oryzias latipes) and Daphnia magna to a range of concentrations of boscalid (1–1000 μg/L) for 24 h, and the effects on heart rate (HR), basal locomotor activity (BLA), visual motor response (VMR), startle response (SR), and habituation (HB) to a series of vibrational or light stimuli have been evaluated. Moreover, changes in the profile of the main neurotransmitters have been determined. Boscalid altered HR in a concentration-dependent manner, leading to a positive or negative chronotropic effect in fish and D. magna, respectively. While boscalid decreased BLA and increased VMR in Daphnia, these behaviors were not altered in fish. For SR and HB, the response was more species- and concentration-specific, with Daphnia exhibiting the highest sensitivity. At the neurotransmission level, boscalid exposure decreased the levels of L-aspartic acid in fish larvae and increased the levels of dopaminergic metabolites in D. magna. Our study demonstrates that exposure to environmental levels of boscalid alters cardiac activity, impairs ecologically relevant behaviors, and leads to changes in different neurotransmitter systems in phylogenetically distinct vertebrate and invertebrate models. Thus, the results presented emphasize the need to review the current regulation of this fungicide.

Is badfiction processed differently by the human brain? An electrophysical study on reading experience.

Literary reception is a special case of language processing. The judgment of literature reveals deep social patterns with embodied cognition. In this study, we investigate how differences in literary quality resonate in the human brain. Modifying a series of stimuli previously used in studies of the emotional potential of Harry Potter, we alternate passages from the original novels with passages from imitative and intentionally poorly written fanfiction. EEG data shows how the three text types are processed differently by the brain. Comparing the brain activity of the readers for the various text types, we see a difference in the absolute power but not in the relative power of the frequency bands. Reading badfiction evokes the lowest activity. However, the functionality of this activity is the same for all texts since the relative power of the frequency bands does not differ. When comparing the participant groups, we observe the opposite situation. Here, different relative powers of the frequency bands reflect different judgments and reading habits of participants. For example, fans of Harry Potter, regular readers of fantasy texts, and generally frequent readers read the texts more attentively, which is reflected in a pronounced relative activity of the theta and alpha frequency bands. Non-frequent readers and readers who are not devoted to Harry Potter and fantasy in general have increased activity in the delta frequency band. This suggests their saliency detection is more prominent because they are less familiar with reading or the subject matter. To support our findings, we use the EEG data without averaging over stimuli and participants, capturing the participants' responses on the level of individual stimuli. A Kohonen self-organizing map trained on this more extensive data finds reliably detectable differences in the responses to passages from the original Harry Potter novels and fan- and badfiction. Our study allows for an interpretation of an adaptive brain response. Readers who enjoy Harry Potter or have experience with the fantasy genre show different reactions from those who do not. Thus, badfiction appears to be processed differently by the human brain, but not for all readers in the same way.

О корректности математической модели вызванной активности первичной зрительной коры

We propose a mathematical model that formalizes the macro- and meso-level dynamics of electrical potentials in the primary visual cortex of subjects, which corresponds to the presentation of visual stimuli to them. The mathematical framework is based on a twolayer neural field model, represented by a system of integro-differential equations, where the deep layer of the neural field models electrical activity that does not depend directly on the spatial orientation of the visual stimuli, whereas the activity of the superficial layer is sensitive to spatially oriented stimuli. The experimental design of presenting a series of visual stimuli is formalised in the present study in terms of an impulse control problem for the aforementioned two-layer neural field model. We propose a special metric space for construction of a unique solution to the control problem under standard assumptions for mathematical neurobiology regarding the functions involved in the modeling equations. We formulate sufficient conditions for continuous dependence of the solutions on the impulse control.

Overlearned sequence and perceived time: possible involvement of attention.

Overlearned sequences, characterized by specific ordinal ranks for each element, elicit strong predictions when presented in their natural order. The present study aimed to test the role of predictions on the perceived duration in a stimulus series that followed an overlearned sequence. Participants judged the duration of the target digit in a sequence that followed a regular or random order, while the overall context in which these sequences were presented was varied in two blocks. The results suggest that, with the possible involvement of attention, the target element that followed the regular order was perceived to be relatively accurate. The violation of an overlearned sequence leads to an underestimation of duration, particularly when the participants are aware of the violation. Further, the perceived duration of the target element in an overlearned sequence does not modulate as a function of the global context. These findings contribute to our understanding of the differential effect of various predictive processes on perceived time.

PANoptosis: Mechanism and Role in Pulmonary Diseases.

PANoptosis is a newly defined programmed cell death (PCD) triggered by a series of stimuli, and it engages three well-learned PCD forms (pyroptosis, apoptosis, necroptosis) concomitantly. Normally, cell death is recognized as a strategy to eliminate unnecessary cells, inhibit the proliferation of invaded pathogens and maintain homeostasis; however, vigorous cell death can cause excessive inflammation and tissue damage. Acute lung injury (ALI) and chronic obstructive pulmonary syndrome (COPD) exacerbation is related to several pathogens (e.g., influenza A virus, SARS-CoV-2) known to cause PANoptosis. An understanding of the mechanism and specific regulators may help to address the pathological systems of these diseases. This review presents our understanding of the potential mechanism of PANoptosis and the role of PANoptosis in different pulmonary diseases.

Investigating the optimal stimulus to evoke the binaural interaction component of the auditory brainstem response

Objective assessment of spatial and binaural hearing deficits remains a major clinical challenge. The binaural interaction component (BIC) of the auditory brainstem response (ABR) holds promise as a non-invasive biomarker for diagnosing such deficits. However, while comparative studies have reported robust BIC in animal models, BIC in humans can sometimes be unreliably evoked even in subjects with normal hearing. Here we explore the hypothesis that the standard methodology for collecting monaural ABRs may not be ideal for electrophysiological assessment of binaural hearing. This study aims to improve ABR BIC measurements by determining more optimal stimuli to evoke it. Building on previous methodology demonstrated to enhance peak amplitude of monaural ABRs, we constructed a series of level-dependent chirp stimuli based on empirically derived latencies of monaural-evoked ABR waves I, IV and the binaural-evoked BIC DN1, the most prominent BIC peak, in a cohort of ten chinchillas. We hypothesized that chirps designed based on BIC DN1 latency would specifically enhance across-frequency temporal synchrony in the afferent inputs leading to the binaural circuits that produce the BIC and would thus produce a larger DN1 than either traditional clicks or chirps designed to optimize monaural ABRs. Compared to clicks, we found that level-specific chirp stimuli evoked significantly greater BIC DN1 amplitudes, and that this effect persisted across all stimulation levels tested. However, we found no significant differences between BICs resulting from chirps created using binaural-evoked BIC DN1 latencies and those using monaural-evoked ABR waves I or IV. These data indicate that existing level-specific, monaural-based chirp stimuli may improve BIC detectability and reduce variability in human BIC measurements.

Interplay between noxious heat sensitivity and temporal summation magnitude in patients with fibromyalgia and long-term opioid use.

In chronic pain conditions such as fibromyalgia (FM), pain amplification within the central nervous system, or "central sensitization," may contribute to the development and maintenance of chronic pain. Chronic pain treatments include opioid therapy, and opioid therapy may maladaptively increase central sensitization, particularly in patients who take opioids long-term. However, it has remained unknown how central sensitization is impacted in patients who use opioids long-term. To investigate how long-term opioid therapy affects central sensitization, we used the validated measure of temporal summation. The temporal summation measurement consists of applying a series of noxious stimuli to a patient's skin and then calculating changes in the patient's pain rating to each stimulus. Using this measurement, we evaluated temporal summation in study participants with fibromyalgia who take opioids long-term (i.e., greater than 90 days duration; n = 24, opioid-FM). We compared opioid-FM responses to 2 control groups: participants with fibromyalgia who do not take opioids (n = 33, non-opioid FM), and healthy controls (n = 31). For the temporal summation measurement, we applied a series of 10 noxious heat stimuli (sensitivity-adjusted temperatures) to the ventral forearm (2s duration of each stimulus, applied once every 3 s). Additionally, we collected responses to standard pain and cognitive-affective questionnaires to assess pain severity and other factors. Group differences in sensitivity-adjusted stimulus temperatures were observed, with only the non-opioid FM group requiring significantly lower stimulus temperatures (The opioid-FM group also required lower temperatures, but not significantly different from the control group). However, all 3 groups exhibited similar magnitudes of temporal summation. Across combined FM groups, temporal summation negatively correlated with pain severity (r = -0.31, p = 0.021). Within the opioid-FM group, higher pain sensitivity to heat (i.e., lower sensitivity-adjusted temperatures) showed a trend relationship with higher opioid dosage (r = -0.45, p = 0.036), potentially reflective of opioid-related hyperalgesia. Our findings also indicated that heightened pain severity may skew sensitivity-adjusted temporal summation, thereby limiting its utility for measuring central sensitization. Overall, in participants taking opioids, temporal summation may be influenced by hypersensitivity to heat pain, which appeared to vary with opioid dosage.

Linear integration of multisensory signals in the pupil.

The pupil of the eye responds to various salient signals from different modalities, but there is no consensus on how these pupillary responses are integrated when multiple signals appear simultaneously. Both linear and nonlinear integration have been found previously. The current study aimed to reexamine the nature of pupillary integration, and specifically focused on the early, transient pupillary responses due to its close relationship with orienting. To separate the early pupillary responses out of the pupil time series, we adopted a pupil oscillation paradigm in which sensory stimuli were periodically presented. The simulation analysis confirmed that the amplitude of the pupil oscillation, induced by stimuli repeatedly presented at relatively high rates, can precisely reflect the early, transient pupillary responses without involving the late and sustained pupillary responses. The experimental results then showed that the amplitude of pupil oscillation induced by a series of simultaneous audiovisual stimuli equaled to a linear summation of the oscillatory amplitudes when unisensory stimuli were presented alone. Moreover, the tonic arousal levels, indicated by the baseline pupil size, cannot shift the summation from linear to nonlinear. These findings together support the additive nature of multisensory pupillary integration for the early, orienting-related pupillary responses. The additive nature of pupillary integration further implies that multiple pupillary responses may be independent of each other, irrespective of their potential cognitive and neural drivers.

Machine learning for distinguishing saudi children with and without autism via eye-tracking data

BackgroundDespite the prevalence of Autism Spectrum Disorder (ASD) globally, there’s a knowledge gap pertaining to autism in Arabic nations. Recognizing the need for validated biomarkers for ASD, our study leverages eye-tracking technology to understand gaze patterns associated with ASD, focusing on joint attention (JA) and atypical gaze patterns during face perception. While previous studies typically evaluate a single eye-tracking metric, our research combines multiple metrics to capture the multidimensional nature of autism, focusing on dwell times on eyes, left facial side, and joint attention.MethodsWe recorded data from 104 participants (41 neurotypical, mean age: 8.21 ± 4.12 years; 63 with ASD, mean age 8 ± 3.89 years). The data collection consisted of a series of visual stimuli of cartoon faces of humans and animals, presented to the participants in a controlled environment. During each stimulus, the eye movements of the participants were recorded and analyzed, extracting metrics such as time to first fixation and dwell time. We then used these data to train a number of machine learning classification algorithms, to determine if these biomarkers can be used to diagnose ASD.ResultsWe found no significant difference in eye-dwell time between autistic and control groups on human or animal eyes. However, autistic individuals focused less on the left side of both human and animal faces, indicating reduced left visual field (LVF) bias. They also showed slower response times and shorter dwell times on congruent objects during joint attention (JA) tasks, indicating diminished reflexive joint attention. No significant difference was found in time spent on incongruent objects during JA tasks. These results suggest potential eye-tracking biomarkers for autism. The best-performing algorithm was the random forest one, which achieved accuracy = 0.76 ± 0.08, precision = 0.78 ± 0.13, recall = 0.84 ± 0.07, and F1 = 0.80 ± 0.09.ConclusionsAlthough the autism group displayed notable differences in reflexive joint attention and left visual field bias, the dwell time on eyes was not significantly different. Nevertheless, the machine algorithm model trained on these data proved effective at diagnosing ASD, showing the potential of these biomarkers. Our study shows promising results and opens up potential for further exploration in this under-researched geographical context.

Strong but Fragmented Memory of a Stressful Episode.

While it is commonly assumed that stressful events are vividly remembered, it remains largely unknown whether all aspects of memory for a stressful episode are enhanced. In this preregistered study, we tested whether stress enhances later remembering of individual elements of a stressful episode at the cost of impaired processing of the association between these elements. Therefore, male and female participants (N = 122) underwent a stressful (or control) episode during which they encoded a series of stimuli. To investigate stress effects on the memory for individual events and the links between these, we used temporal sequence effects in recognition memory tested 24 h after encoding. Specifically, we tested whether stress would affect the memory enhancement for a target item if this is preceded by another item that also preceded the target during encoding (recognition priming). Our results showed that participants recalled single events encoded under stress better than those encoded under nonstressful conditions, but were less able to leverage the temporal sequence of events encoded under stress to cue memory at delayed recall, reflected in reduced memory for items preceded by the item that preceded them also during encoding. Functional near-infrared spectroscopy further revealed that encoding under stress was accompanied by opposite changes in inferotemporal and dorsolateral prefrontal areas. Together, our data suggest that acute stress induces a mode of memory formation that results in strong but less integrated memories.