In memory, our continuous experiences are broken up into discrete events. Boundaries between events are known to influence the temporal organization of memory. However, how and through which ...mechanism event boundaries shape temporal order memory (TOM) remains unknown. Across four experiments, we show that event boundaries exert a dual role: improving TOM for items within an event and impairing TOM for items across events. Decreasing event length in a list enhances TOM, but only for items at earlier local event positions, an effect we term the local primacy effect. A computational model, in which items are associated to a temporal context signal that drifts over time but resets at boundaries captures all behavioural results. Our findings provide a unified algorithmic mechanism for understanding how and why event boundaries affect TOM, reconciling a long-standing paradox of why both contextual similarity and dissimilarity promote TOM.
Room‐temperature sodium–sulfur (RT‐Na/S) batteries possess high potential for grid‐scale stationary energy storage due to their low cost and high energy density. However, the issues arising from the ...low S mass loading and poor cycling stability caused by the shuttle effect of polysulfides seriously limit their operating capacity and cycling capability. Herein, sulfur‐doped graphene frameworks supporting atomically dispersed 2H‐MoS2 and Mo1 (S@MoS2‐Mo1/SGF) with a record high sulfur mass loading of 80.9 wt.% are synthesized as an integrated dual active sites cathode for RT‐Na/S batteries. Impressively, the as‐prepared S@MoS2‐Mo1/SGF display unprecedented cyclic stability with a high initial capacity of 1017 mAh g−1 at 0.1 A g−1 and a low‐capacity fading rate of 0.05% per cycle over 1000 cycles. Experimental and computational results including X‐ray absorption spectroscopy, in situ synchrotron X‐ray diffraction and density‐functional theory calculations reveal that atomic‐level Mo in this integrated dual‐active‐site forms a delocalized electron system, which could improve the reactivity of sulfur and reaction reversibility of S and Na, greatly alleviating the shuttle effect. The findings not only provide an effective strategy to fabricate high‐performance dual‐site cathodes, but also deepen the understanding of their enhancement mechanisms at an atomic level.
An integrated dual‐active‐site cathode is developed by wreathing monolayered MoS2 and Mo1 on sulfur‐doped graphene frameworks for high‐performance room‐temperature sodium–sulfur batteries. The constructed atomic level MoS2‐Mo1 with delocalized electron effects facilitates substantial charge transfer and a completely reversible reaction between S and Na, thus alleviating the shuttle effect.
Understanding the evolutionarily conserved feature of functional laterality in the habenula has been attracting attention due to its potential role in human cognition and neuropsychiatric disorders. ...Deciphering the structure of the human habenula remains to be challenging, which resulted in inconsistent findings for brain disorders. Here, we present a large‐scale meta‐analysis of the left–right differences in the habenular volume in the human brain to provide a clearer picture of the habenular asymmetry. We searched PubMed, Web of Science, and Google Scholar for articles that reported volume data of the bilateral habenula in the human brain, and assessed the left–right differences. We also assessed the potential effects of several moderating variables including the mean age of the participants, magnetic field strengths of the scanners and different disorders by using meta‐regression and subgroup analysis. In total 52 datasets (N = 1427) were identified and showed significant heterogeneity in the left–right differences and the unilateral volume per se. Moderator analyses suggested that such heterogeneity was mainly due to different MRI scanners and segmentation approaches used. While inversed asymmetry patterns were suggested in patients with depression (leftward) and schizophrenia (rightward), no significant disorder‐related differences relative to healthy controls were found in either the left–right asymmetry or the unilateral volume. This study provides useful data for future studies of brain imaging and methodological developments related to precision habenula measurements, and also helps to further understand potential roles of the habenula in various disorders.
We present a large‐scale meta‐analysis of the habenula volume and its asymmetry in humans. Results revealed significant heterogeneity and important methodological factors. No significant disorder‐related differences in the habenula measures were found.
Representing brain morphology as a network has the advantage that the regional morphology of 'isolated' structures can be described statistically based on graph theory. However, very few studies have ...investigated brain morphology from the holistic perspective of complex networks, particularly in individual brains. We proposed a new network framework for individual brain morphology. Technically, in the new network, nodes are defined as regions based on a brain atlas, and edges are estimated using our newly-developed inter-regional relation measure based on regional morphological distributions. This implementation allows nodes in the brain network to be functionally/anatomically homogeneous but different with respect to shape and size. We first demonstrated the new network framework in a healthy sample. Thereafter, we studied the graph-theoretical properties of the networks obtained and compared the results with previous morphological, anatomical, and functional networks. The robustness of the method was assessed via measurement of the reliability of the network metrics using a test-retest dataset. Finally, to illustrate potential applications, the networks were used to measure age-related changes in commonly used network metrics. Results suggest that the proposed method could provide a concise description of brain organization at a network level and be used to investigate interindividual variability in brain morphology from the perspective of complex networks. Furthermore, the method could open a new window into modeling the complexly distributed brain and facilitate the emerging field of human connectomics.
Lateralization is a fundamental characteristic of many behaviors and the organization of the brain, and atypical lateralization has been suggested to be linked to various brain-related disorders such ...as autism and schizophrenia. Right-handedness is one of the most prominent markers of human behavioural lateralization, yet its neurobiological basis remains to be determined. Here, we present a large-scale analysis of handedness, as measured by self-reported direction of hand preference, and its variability related to brain structural and functional organization in the UK Biobank (N = 36,024). A multivariate machine learning approach with multi-modalities of brain imaging data was adopted, to reveal how well brain imaging features could predict individual's handedness (i.e., right-handedness vs. non-right-handedness) and further identify the top brain signatures that contributed to the prediction. Overall, the results showed a good prediction performance, with an area under the receiver operating characteristic curve (AUROC) score of up to 0.72, driven largely by resting-state functional measures. Virtual lesion analysis and large-scale decoding analysis suggested that the brain networks with the highest importance in the prediction showed functional relevance to hand movement and several higher-level cognitive functions including language, arithmetic, and social interaction. Genetic analyses of contributions of common DNA polymorphisms to the imaging-derived handedness prediction score showed a significant heritability (h2=7.55%, p <0.001) that was similar to and slightly higher than that for the behavioural measure itself (h2=6.74%, p <0.001). The genetic correlation between the two was high (rg=0.71), suggesting that the imaging-derived score could be used as a surrogate in genetic studies where the behavioural measure is not available. This large-scale study using multimodal brain imaging and multivariate machine learning has shed new light on the neural correlates of human handedness.
Face-selective regions (FSRs) are among the most widely studied functional regions in the human brain. However, individual variability of the FSRs has not been well quantified. Here we use functional ...magnetic resonance imaging (fMRI) to localize the FSRs and quantify their spatial and functional variabilities in 202 healthy adults. The occipital face area (OFA), posterior and anterior fusiform face areas (pFFA and aFFA), posterior continuation of the superior temporal sulcus (pcSTS), and posterior and anterior STS (pSTS and aSTS) were delineated for each individual with a semi-automated procedure. A probabilistic atlas was constructed to characterize their interindividual variability, revealing that the FSRs were highly variable in location and extent across subjects. The variability of FSRs was further quantified on both functional (i.e., face selectivity) and spatial (i.e., volume, location of peak activation, and anatomical location) features. Considerable interindividual variability and rightward asymmetry were found in all FSRs on these features. Taken together, our work presents the first effort to characterize comprehensively the variability of FSRs in a large sample of healthy subjects, and invites future work on the origin of the variability and its relation to individual differences in behavioral performance. Moreover, the probabilistic functional atlas will provide an adequate spatial reference for mapping the face network.
•A probabilistic functional atlas for face-selective regions was created based on 202 adults.•The atlas consists of six face-selective regions in the occipitotemporal cortex.•The atlas shows significantly interindividual and interhemispheric variability.•The atlas provides a spatial reference for neuroimaging studies on face processing.
• In Orchidaceae, pollination is mostly animal-mediated, and one-third of species have evolved a deceptive pollination mechanism without rewards. Cypripedium is a representative lineage of ...nonrewarding orchids restricted to temperate regions. Cypripedium subtropicum flowers are pollinated by hoverflies and have hairy tufts that visually resemble an aphid colony covered with honey dew.
• We recorded the behavior of hoverflies on the flowers, determined the breeding system of the species and the structure of hairy tufts, and investigated the roles of hairy tufts and floral volatiles in this specialized pollination by using pollination experiments, scanning electron microscopy, bioassays and chemical analyses.
• The white hairy tufts covering the sidelobes of the labellum provide edible rewards and serve as crucial visual lures for hoverflies. The flowers emit primarily (E)-β-farnesene and a smaller amount of β-pinene that were found to attract hoverflies.
• Our results suggest that C. subtropicum uses both visual mimicry of an aphid-colonized labellum with a reward and chemical mimicry of aphid alarm pheromones to attract hoverflies for pollination. This is the first described example of a rewarding mimicry system in plants, where the models are animals with their secretions and the reward is similar in nutrients to that of the model mimicked.
Magnetic resonance imaging (MRI) provides valuable data for understanding the human mind and brain disorders, but in-scanner head motion introduces systematic and spurious biases. For example, ...differences in MRI measures (e.g., network strength, white matter integrity) between patient and control groups may be due to the differences in their head motion. To determine whether head motion is an important variable in itself, or just simply a confounding variable, we explored individual differences in psychological traits that may predispose some people to move more than others during an MRI scan. In the first two studies, we demonstrated in both children (N = 245) and adults (N = 581) that head motion, estimated from resting-state functional MRI and diffusion tensor imaging, was reliably correlated with impulsivity scores. Further, the difference in head motion between children with attention deficit hyperactivity disorder (ADHD) and typically developing children was largely due to differences in impulsivity. Finally, in the third study, we confirmed the observation that the regression approach, which aims to deal with motion issues by regressing out motion in the group analysis, would underestimate the effect of interest. Taken together, the present findings provide empirical evidence that links in-scanner head motion to psychological traits.
•A new metric was proposed to quantify individual morphological relations of regions.•The new metric is indexed as the similarity of different morphological distributions.•We estimate the ...morphological distribution from individual MRI image.•The metric seemed to have potential application to individual differences studies.
Although local features of brain morphology have been widely investigated in neuroscience, the inter-regional relations in brain morphology have rarely been investigated, especially not for individual participants.
In this paper, we proposed a novel framework for investigating this relation based on an individual's magnetic resonance imaging (MRI) data. The key idea was to estimate the probability density function (PDF) of local morphological features within a brain region to provide a global description of this region. Then, the inter-regional relations were quantified by calculating the similarity of the PDFs for pairs of regions based on the Kullback–Leibler (KL) divergence.
For illustration, we applied this approach to a pre-post intervention study to investigate the longitudinal changes in morphological relations after long-term sleep deprivation. The results suggest the potential application of this new method for studies on individual differences in brain structure.
The current method can be employed to estimate individual morphological relations between regions, which have been largely ignored by previous studies.
Our morphological relation metric, as a novel quantitative biomarker, can be used to investigate normal individual variability and even within-individual alterations/abnormalities in brain structure.
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