Memory Monitoring and Control in Japanese and German Preschoolers.

Prior studies explored the early development of memory monitoring and control. However, little work has examined cross-cultural similarities and differences in metacognitive development in early childhood. In the present research, we investigated a total of 100 Japanese and German preschool-aged children's memory monitoring and control in a visual perception task. After seeing picture items, some of which were repeated, children were presented with picture pairs, one of which had been presented earlier and the other was a novel item. They then were asked to identify the previously presented picture. Children were also asked to evaluate their confidence about their selection, and to sort the responses to be used for being awarded with a prize at the end of the test. Both groups similarly expressed more confidence in the accurately remembered items than in the inaccurately remembered items, and their sorting decision was based on their subjective confidence. Japanese children's sorting more closely corresponded to memory accuracy than German children's sorting, however. These findings were further confirmed by a hierarchical Bayesian estimation of metacognitive efficiency. The present findings therefore suggest that early memory monitoring and control have both culturally similar and diverse aspects. The findings are discussed in light of broader sociocultural influences on metacognition.

Metacognition and mindreading in young children: A cross-cultural study.

Prior studies document cross cultural variation in the developmental onset of mindreading. In particular, Japanese children are reported to pass a standard false belief task later than children from Western countries. By contrast, we know little about cross-cultural variation in young children's metacognitive abilities. Moreover, one prominent theoretical discussion in developmental psychology focuses on the relation between metacognition and mindreading. Here we investigated the relation between mindreading and metacognition (both implicit and explicit) by testing 4-year-old Japanese and German children. We found no difference in metacognition between the two cultural groups. By contrast, Japanese children showed lower performance than German children replicating cultural differences in mindreading. Finally, metacognition and mindreading were not related in either group. We discuss the findings in light of the existing theoretical accounts of the relation between metacognition and mindreading.

Age-related differences in the activation of the mentalizing- and reward-related brain regions during the learning of others' true trustworthiness.

Behavioral studies suggest that older adults may be less adept than younger adults at remembering information contradicting their first impressions about others' trustworthiness. To identify the neural bases associated with such age-related differences, we measured the brain activity of older and younger participants using functional magnetic resonance imaging while they processed feedback on whether their initial trustworthiness impressions of stimulus persons, whose true trustworthiness had been predetermined, were right or wrong. Of special interest was the activation in mentalizing- (e.g., medial prefrontal cortex) and reward-related brain regions (e.g., striatum), which are known to be involved in impression formation and feedback learning, respectively. The reduction in the striatal responses to impression-contradicting versus impression-confirming feedback was greater in older than in younger participants. The activation of some mentalizing-related regions (medial prefrontal cortex and precuneus) was lower in older than younger participants; however, it was not modulated by impression-feedback congruency. The results suggest that age-related differences in the striatum engagement may underlie older adults' inefficiency in learning impression-incongruent information about others' trustworthiness.

Do Infants Attribute Moral Traits? Fourteen-Month-Olds' Expectations of Fairness Are Affected by Agents' Antisocial Actions.

We investigated whether and how infants link the domains of harm, help and fairness. Fourteen-month-old infants were familiarized with a character that either helped or hindered another agent's attempts to reach the top of a hill. Then, in the test phase they saw the helper or the hinderer carrying out an equal or an unequal distribution toward two identical recipients. Infants who saw the helper performing an unequal distribution looked longer than those who saw the helper performing an equal distribution, whereas infants who saw the hinderer performing an unequal distribution looked equally long than those who saw the hinderer performing an equal distribution. These results suggest that infants linked the hindering actions to a diminished propensity for distributive fairness. This provides support for theories that posit an early emerging ability to attribute moral traits to agents and to generate socio-moral evaluations of their actions. RESEARCH HIGHLIGHTS  - Infants expect agents that previously helped another agent to perform egalitarian distributions, but they do not generate such expectation about agents that previously hindered another agent. - This ability to link hindering and distributive actions is important because it may help the development of reasoning about agents' stable moral traits. - Results provide support for recent theories on early social evaluation skills and they constraint theories on the acquisition of moral competence.

Improved Volitional Recall of Motor-Imagery-Related Brain Activation Patterns Using Real-Time Functional MRI-Based Neurofeedback.

Motor imagery (MI), a covert cognitive process where an action is mentally simulated but not actually performed, could be used as an effective neurorehabilitation tool for motor function improvement or recovery. Recent approaches employing brain-computer/brain-machine interfaces to provide online feedback of the MI during rehabilitation training have promising rehabilitation outcomes. In this study, we examined whether participants could volitionally recall MI-related brain activation patterns when guided using neurofeedback (NF) during training. The participants' performance was compared to that without NF. We hypothesized that participants would be able to consistently generate the relevant activation pattern associated with the MI task during training with NF compared to that without NF. To assess activation consistency, we used the performance of classifiers trained to discriminate MI-related brain activation patterns. Our results showed significantly higher predictive values of MI-related activation patterns during training with NF. Additionally, this improvement in the classification performance tends to be associated with the activation of middle temporal gyrus/inferior occipital gyrus, a region associated with visual motion processing, suggesting the importance of performance monitoring during MI task training. Taken together, these findings suggest that the efficacy of MI training, in terms of generating consistent brain activation patterns relevant to the task, can be enhanced by using NF as a mechanism to enable participants to volitionally recall task-related brain activation patterns.

Selective learning and teaching among Japanese and German children.

Despite an increasing number of studies demonstrating that young children selectively learn from others, and a few studies of children's selective teaching, the evidence almost exclusively comes from Western cultures, and cross-cultural comparison in this line of work is very rare. In the present research, we investigated Japanese and German children's selective learning and teaching abilities. We found clear cultural differences. Japanese children were better at selectively teaching an ignorant person over a knowledgeable person than at selectively learning from knowledgeable others. By contrast, German children were better at choosing to learn from a knowledgeable rather than from an ignorant person than at selectively teaching ignorant others. The present findings suggest that the development of human learning and teaching, especially the tendency to take into account others' knowledge status, is strongly affected by cultural background. (PsycINFO Database Record

Predictions of Cleavability of Calpain Proteolysis by Quantitative Structure-Activity Relationship Analysis Using Newly Determined Cleavage Sites and Catalytic Efficiencies of an Oligopeptide Array.

Calpains are intracellular Ca(2+)-regulated cysteine proteases that are essential for various cellular functions. Mammalian conventional calpains (calpain-1 and calpain-2) modulate the structure and function of their substrates by limited proteolysis. Thus, it is critically important to determine the site(s) in proteins at which calpains cleave. However, the calpains' substrate specificity remains unclear, because the amino acid (aa) sequences around their cleavage sites are very diverse. To clarify calpains' substrate specificities, 84 20-mer oligopeptides, corresponding to P10-P10' of reported cleavage site sequences, were proteolyzed by calpains, and the catalytic efficiencies (kcat/Km) were globally determined by LC/MS. This analysis revealed 483 cleavage site sequences, including 360 novel ones. Thekcat/Kms for 119 sites ranged from 12.5-1,710 M(-1)s(-1) Although most sites were cleaved by both calpain-1 and -2 with a similarkcat/Km, sequence comparisons revealed distinct aa preferences at P9-P7/P2/P5'. The aa compositions of the novel sites were not statistically different from those of previously reported sites as a whole, suggesting calpains have a strict implicit rule for sequence specificity, and that the limited proteolysis of intact substrates is because of substrates' higher-order structures. Cleavage position frequencies indicated that longer sequences N-terminal to the cleavage site (P-sites) were preferred for proteolysis over C-terminal (P'-sites). Quantitative structure-activity relationship (QSAR) analyses using partial least-squares regression and >1,300 aa descriptors achievedkcat/Kmprediction withr= 0.834, and binary-QSAR modeling attained an 87.5% positive prediction value for 132 reported calpain cleavage sites independent of our model construction. These results outperformed previous calpain cleavage predictors, and revealed the importance of the P2, P3', and P4' sites, and P1-P2 cooperativity. Furthermore, using our binary-QSAR model, novel cleavage sites in myoglobin were identified, verifying our predictor. This study increases our understanding of calpain substrate specificities, and opens calpains to "next-generation,"i.e.activity-related quantitative and cooperativity-dependent analyses.

The epigenesis of wariness of heights.

Human infants with little or no crawling experience surprisingly show no wariness of heights, but such wariness becomes exceptionally strong over the life span. Neither depth perception nor falling experiences explain this extraordinary developmental shift; however, something about locomotor experience does. The crucial component of locomotor experience in this emotional change is developments in visual proprioception-the optically based perception of self-movement. Precrawling infants randomly assigned to drive a powered mobility device showed significantly greater visual proprioception, and significantly greater wariness of heights, than did controls. More important, visual proprioception mediated the relation between wariness of heights and locomotor experience. In a separate study, crawling infants' visual proprioception predicted whether they would descend onto the deep side of a visual cliff, a finding that confirms the importance of visual proprioception in the development of wariness of heights.

Structural basis for specific recognition of Rpt1p, an ATPase subunit of 26 S proteasome, by proteasome-dedicated chaperone Hsm3p.

The 26 S proteasome is a 2.5-MDa molecular machine that degrades ubiquitinated proteins in eukaryotic cells. It consists of a proteolytic core particle and two 19 S regulatory particles (RPs) composed of 6 ATPase (Rpt) and 13 non-ATPase (Rpn) subunits. Multiple proteasome-dedicated chaperones facilitate the assembly of the proteasome, but little is known about the detailed mechanisms. Hsm3, a 19 S RP dedicated chaperone, transiently binds to the C-terminal domain of the Rpt1 subunit and forms a tetrameric complex, Hsm3-Rpt1-Rpt2-Rpn1, during maturation of the ATPase ring of 19 S RP. To elucidate the structural basis of Hsm3 function, we determined the crystal structures of Hsm3 and its complex with the C-terminal domain of the Rpt1 subunit (Rpt1C). Hsm3 has a C-shaped structure that consists of 11 HEAT repeats. The structure of the Hsm3-Rpt1C complex revealed that the interacting surface between Hsm3 and Rpt1 is a hydrophobic core and a complementary charged surface. Mutations in the Hsm3-Rpt1 surface resulted in the assembly defect of the 26 S proteasome. Furthermore, a structural model of the Hsm3-Rpt ring complex and an in vitro binding assay suggest that Hsm3 can bind Rpt2 in addition to Rpt1. Collectively, our results provide the structural basis of the molecular functions of Hsm3 for the RP assembly.

Efficient expression and purification of recombinant human m-calpain using an Escherichia coli expression system at low temperature.

Calpain belongs to the superfamily of Ca(2+)-regulated cysteine proteases, which are indispensable to the regulation of various cellular functions. Of the 15 mammalian calpain isoforms, µ- and m-calpains are the best characterized. Both µ- and m-calpain are ubiquitously expressed and exist as heterodimers, containing a distinct 80-kDa catalytic subunit (CAPN1 and CAPN2, respectively) and the common, 30-kDa regulatory subunit (CAPNS1). To date, various expression systems have been developed for producing recombinant calpains for use in structural and physiological studies, however Escherichia coli systems have proven incompatible with large-scale preparation of calpain, with the exception of rat m-calpain. Here, we have established a highly efficient method to purify active recombinant human m-calpain using an E. coli expression system at low temperature (22°C). This was achieved by co-expressing CAPN2 with a C-terminal histidine-tag, and CAPNS1, lacking the first Gly-repeated region at the N-terminal. After three sequential passes through a chromatographic column, ~5 mg of human m-calpain was homogenously purified from 1 l of E. coli culture. Proteins were stable for several months. This is the first report of efficient, large-scale purification of recombinant human m-calpain using an E. coli expression system.

The Organization of Wariness of Heights in Experienced Crawlers.

Most infants with more than 6 weeks of crawling experience completely avoid the deep side of a visual cliff (Campos et al., 1992; Gibson & Walk, 1960). However, some experienced crawlers do move onto the transparent surface suspended several feet above the ground. An important question is whether these non-avoiders lack wariness of heights or whether they have a qualitatively different way of showing their wariness than do avoiders of the deep side. The current study addressed this question by measuring heart rate (HR) acceleration upon being lowered on the deep and shallow sides of the visual cliff, latency to crawl toward the mother, and tactile exploration of the cliff surface. Non-avoiders and avoiders had indistinguishable patterns of HR acceleration, showing greater HR acceleration when lowered onto the deep than when lowered onto the shallow side of the cliff. Non-avoiders also showed more tactile exploration and longer latencies than did a comparable group of infants tested on the shallow side. This study illustrates how the same emotion, wariness of heights, can be shown by qualitatively different behaviors, all serving the same function of protecting the individual from falling over a drop-off.