How bearded capuchin monkeys (Sapajus libidinosus) prepare to use a stone to crack nuts

Bearded capuchin monkeys crack nuts with naturally varying stone hammers, suggesting they may tune their grips and muscular forces to each stone. If so, they might use discrete actions on a stone before lifting and striking, and they would likely use these actions more frequently when the stone is larger and/or less familiar and/or when first initiating striking. We examined the behavior of (a) four monkeys (all proficient at cracking nuts) with two larger (1 kg) and two smaller (0.5 kg) stones, (b) 12 monkeys with one 1 kg stone, and (c) one monkey during its first 100 strikes with an initially unfamiliar 1 kg stone. Bearded capuchin monkeys used three discrete actions on the stone before striking, all more often with the larger stones than the smaller stones. We infer that the first discrete action (Spin) aided the monkey in determining where to grip the stone, the second (Flip) allowed it to position the stone on the anvil ergonomically before lifting it, and the third (Preparatory Lift) readied the monkey for the strenuous lifting action. The monkey that provided 100 strikes with one initially unfamiliar stone performed fewer Spins in later strikes but performed Flip and Preparatory Lift at consistent rates. The monkeys gripped the stone with both hands along the sides to lift it, but usually moved one or both hands to the top of the stone at the zenith of the lift for the downward strike. The findings highlight two new aspects of the capuchins’ nut‐cracking: (a) Anticipatory actions with the stone before striking, especially when the stone is larger or unfamiliar, and when initiating striking and (b) shifting grips on the stone during a strike. We invite researchers to investigate if other taxa use anticipatory actions and shift their grips during percussive activity.     

Multiple Facets of Exploratory Behavior in House Crickets (Acheta domesticus): Split Personalities or Simply Different Behaviors?

Behavioral ecologists are increasingly interested in patterns of repeatable variation in behaviors. The study of this variation, under the label ‘animal personality’, frequently makes assumptions both in regards to what the ecological significance of particular behavioral responses might be and whether different methodologies in fact test the same behavior. Here, using house crickets (Acheta domesticus), we tested whether stereotypical approaches to quantifying repeatable variation in exploratory behavior measured the same behaviors. We found that house cricket exploratory behavior was highly repeatable in two populations (repeatability: 0.37–0.51). However, exploratory behavior across two different testing methods was not strongly correlated (r = ?0.17 to 0.14). This suggests that either different behaviors or distinct components of exploratory behavior were being measured. Our results also support recent criticisms that care needs to be taken in describing personality traits.     

Effects of Different Types of Bedding Materials on Behavioral Development in Laboratory CD1 Mice (Mus musculus)

Male and female mice were housed in cages, containing different types of bedding materials (wood flakes or pulp chips), from 4 weeks of age in the F₀ generation to 11 weeks of age in the F₁ generation; selected reproductive and neurobehavioral parameters were measured in the F₁ generation. There were no adverse effects of bedding materials on litter size, litter weight, or sex ratios at the time of birth. With regard to behavioral development parameters, bedding materials did not influence any variables (p > 0.05) in both sexes. Regarding exploratory behavior in the F₁ generation, number of defecations significantly varied (p = 0.0203) with bedding materials in males at 3 weeks of age. The number of horizontal activities also significantly varied (p = 0.0342) with bedding materials in males at 8 weeks of age. Multiple‐T water maze performance data indicated that the time required was significantly shortened across trials in pulp chips group than wood flakes group in males (p = 0.0211). Moreover, all spontaneous behavior variables in males significantly varied with bedding materials, particularly the average time of movement was significantly different (p = 0.0037) in distance between parallel lines of types of bedding materials in the F₁ generation. The present study shows that bedding materials influence the neurobehavioral development in mice     

Association between DRD4 gene polymorphism and personality variation in great tits: a test across four wild populations

Polymorphisms in the dopamine receptor D4 gene (DRD4) have been related to individual variation in novelty‐seeking or exploratory behaviour in a variety of animals, including humans. Recently, the human DRD4 orthologue was sequenced in a wild bird, the great tit (Parus major) and a single nucleotide polymorphism in exon 3 of this gene (SNP830) was shown to be associated with variation in exploratory behaviour of lab‐raised individuals originating from a single wild population. Here we test the generality of this finding in a large sample of free‐living individuals from four European great tit populations, including the originally sampled population. We demonstrate that the association between SNP830 genotype and exploratory behaviour also exists in free‐living birds from the original population. However, in the other three populations we found only limited evidence for an association: in two populations the association appeared absent; while in one there was a nonsignificant tendency. We could not confirm a previously demonstrated interaction with another DRD4 polymorphism, a 15 bp indel in the promoter region (ID15). As yet unknown differences in genetic or environmental background could explain why the same genetic polymorphism (SNP830) has a substantial effect on exploratory behaviour in one population, explaining 4.5–5.8% of the total variance—a large effect for a single gene influencing a complex behavioural trait—but not in three others. The confirmation of an association between SNP830 genotype and personality‐related behaviour in a wild bird population warrants further research into potential fitness effects of the polymorphism, while also the population differences in the strength of the association deserve further investigation. Another important future challenge is the identification of additional loci influencing avian personality traits in the wild.     

应激诱发的海马神经元突触增强参与大鼠的新环境学习

本文旨在研究应激对海马新环境空间学习记忆的损伤作用机制.在大鼠海马CA1区埋植电极,刺激schaffer侧枝记录CA1区树突层的兴奋性突触后场电位(field excitatory postsynaptic potential,fEPSP),探索应激对火鼠新环境空间学习的突触可塑性的影响.同时研究了再次新环境空间学习时...     

Trajectory Data Analyses for Pedestrian Space-time Activity Study

It is well recognized that human movement in the spatial and temporal dimensions has direct influence on disease transmission^1-3. An infectious disease typically spreads via contact between infected and susceptible individuals in their overlapped activity spaces. Therefore, daily mobility-activity information can be used as an indicator to measure exposures to risk factors of infection. However, a major difficulty and thus the reason for paucity of studies of infectious disease transmission at the micro scale arise from the lack of detailed individual mobility data. Previously in transportation and tourism research detailed space-time activity data often relied on the time-space diary technique, which requires subjects to actively record their activities in time and space. This is highly demanding for the participants and collaboration from the participants greatly affects the quality of data⁴.Modern technologies such as GPS and mobile communications have made possible the automatic collection of trajectory data. The data collected, however, is not ideal for modeling human space-time activities, limited by the accuracies of existing devices. There is also no readily available tool for efficient processing of the data for human behavior study. We present here a suite of methods and an integrated ArcGIS desktop-based visual interface for the pre-processing and spatiotemporal analyses of trajectory data. We provide examples of how such processing may be used to model human space-time activities, especially with error-rich pedestrian trajectory data, that could be useful in public health studies such as infectious disease transmission modeling.The procedure presented includes pre-processing, trajectory segmentation, activity space characterization, density estimation and visualization, and a few other exploratory analysis methods. Pre-processing is the cleaning of noisy raw trajectory data. We introduce an interactive visual pre-processing interface as well as an automatic module. Trajectory segmentation⁵ involves the identification of indoor and outdoor parts from pre-processed space-time tracks. Again, both interactive visual segmentation and automatic segmentation are supported. Segmented space-time tracks are then analyzed to derive characteristics of one''s activity space such as activity radius etc. Density estimation and visualization are used to examine large amount of trajectory data to model hot spots and interactions. We demonstrate both density surface mapping⁶ and density volume rendering⁷. We also include a couple of other exploratory data analyses (EDA) and visualizations tools, such as Google Earth animation support and connection analysis. The suite of analytical as well as visual methods presented in this paper may be applied to any trajectory data for space-time activity studies.     

Social familiarity modulates personality trait in a cichlid fish

Personality traits, such as exploration–avoidance, are expected to be adaptive in a given context (e.g. low-risk environment) but to be maladaptive in others (e.g. high-risk environment). Therefore, it is expected that personality traits are flexible and respond to environmental fluctuations, given that consistency across different contexts is maintained, so that the relative individual responses in relation to others remains the same (i.e. although the magnitude of the response varies the differences between high and low responders are kept). Here, we tested the response of male cichlid fish (Oreochromis mossambicus) to a novel object (NO) in three different social contexts: (i) social isolation, (ii) in the presence of an unfamiliar conspecific, and (iii) in the presence of a familiar conspecific. Males in the familiar treatment exhibited more exploratory behaviour and less neophobia than males in either the unfamiliar or the social isolation treatments. However, there were no overall correlations in individual behaviour across the three treatments, suggesting a lack of consistency in exploration–avoidance as measured by the NO test in this species. Moreover, there were no differences in cortisol responsiveness to an acute stressor between the three treatments. Together, these results illustrate how behavioural traits usually taken as measures of personality may exhibit significant flexibility and lack the expected consistency across different social contexts.     

A new look at neurobehavioral development in rhesus monkey neonates (Macaca mulatta)

The Brazelton Neonatal Behavioral Assessment Scale (NBAS) evaluates a newborn infant's autonomic, motor, state, temperament, and social-attentional systems, which can help to identify infants at risk of developmental problems. Given the prevalence of rhesus monkeys being used as an animal model for human development, here we aimed to validate a standardized test battery modeled after the NBAS for use with nonhuman primates called the Infant Behavioral Assessment Scale (IBAS), employing exploratory structural equation modeling using a large sample of rhesus macaque neonates (n = 1,056). Furthermore, we examined the repeated assessments of the common factors within the same infants to describe any changes in performance over time, taking into account two independent variables (infant sex and rearing condition) that can potentially affect developmental outcomes. Results revealed three factors (Orientation, State Control, and Motor Activity) that all increased over the 1st month of life. While infant sex did not have an effect on any factor, nursery-rearing led to higher scores on Orientation but lower scores on State Control and Motor Activity. These results validate the IBAS as a reliable and valuable research tool for use with rhesus macaque infants and suggest that differences in rearing conditions can affect developmental trajectories and potentially pre-expose infants to heightened levels of cognitive and emotional deficiencies.     

QTL and systems genetics analysis of mouse grooming and behavioral responses to novelty in an open field

The open field is a classic test used to assess exploratory behavior, anxiety and locomotor activity in rodents. Here, we mapped quantitative trait loci (QTLs) underlying behaviors displayed in an open field, using a panel of 53 BXD recombinant inbred mouse strains with deep replication (10 per strain and sex). The use of these strains permits the integration and comparison of data obtained in different laboratories, and also offers the possibility to study trait covariance by exploiting powerful bioinformatics tools and resources. We quantified behavioral traits during 20‐min test sessions including (1) percent time spent and distance traveled near the wall (thigmotaxis), (2) leaning against the wall, (3) rearing, (4) jumping, (5) grooming duration, (6) grooming frequency, (7) locomotion and (8) defecation. All traits exhibit moderate heritability making them amenable to genetic analysis. We identified a significant QTL on chromosome M.m. 4 at approximately 104 Mb that modulates grooming duration in both males and females (likelihood ratio statistic values of approximately 18, explaining 25% and 14% of the variance, respectively) and a suggestive QTL modulating locomotion that maps to the same locus. Bioinformatic analysis indicates Disabled 1 (Dab1, a key protein in the reelin signaling pathway) as a particularly strong candidate gene modulating these behaviors. We also found 2 highly suggestive QTLs for a sex by strain interaction for grooming duration on chromosomes 13 and 17. In addition, we identified a pairwise epistatic interaction between loci on chromosomes 12 at 36–37 Mb and 14 at 34–36 Mb that influences rearing frequency in males.     

ribosort: a program for automated data preparation and exploratory analysis of microbial community fingerprints

ribosort is a computer package for convenient editing of automated ribosomal intergenic spacer analysis (ARISA) and terminal restriction fragment length polymorphism (TRFLP) data. It is designed to eliminate the labourious task of manually classifying community fingerprints in microbial ecology studies. This program automatically assigns detected fragments and their respective relative abundances to appropriate ribotypes. It permits simultaneous sorting of multiple profiles and facilitates direct workflow from TRFLP and ARISA output through to community analyses. ribosort also provides several options to merge repeat profiles of a sample into a single composite profile. By creating a 'ribotypes by samples' matrix ready for statistical analyses, use of the package saves time and simplifies the preparation of DNA fingerprint data sets for statistical analysis. In addition, ribosort performs exploratory analysis on the data by creating multidimensional scaling plots that compare the similarity of sample profiles using the statistical software r.