Abstract
Nanomaterials (NMs) present unique challenges in safety evaluation. An international working group, the Genetic Toxicology Technical Committee of the International Life Sciences Institute’s ...Health and Environmental Sciences Institute, has addressed issues related to the genotoxicity assessment of NMs. A critical review of published data has been followed by recommendations on methods alterations and best practices for the standard genotoxicity assays: bacterial reverse mutation (Ames); in vitro mammalian assays for mutations, chromosomal aberrations, micronucleus induction, or DNA strand breaks (comet); and in vivo assays for genetic damage (micronucleus, comet and transgenic mutation assays). The analysis found a great diversity of tests and systems used for in vitro assays; many did not meet criteria for a valid test, and/or did not use validated cells and methods in the Organization for Economic Co-operation and Development Test Guidelines, and so these results could not be interpreted. In vivo assays were less common but better performed. It was not possible to develop conclusions on test system agreement, NM activity, or mechanism of action. However, the limited responses observed for most NMs were consistent with indirect genotoxic effects, rather than direct interaction of NMs with DNA. We propose a revised genotoxicity test battery for NMs that includes in vitro mammalian cell mutagenicity and clastogenicity assessments; in vivo assessments would be added only if warranted by information on specific organ exposure or sequestration of NMs. The bacterial assays are generally uninformative for NMs due to limited particle uptake and possible lack of mechanistic relevance, and are thus omitted in our recommended test battery for NM assessment. Recommendations include NM characterization in the test medium, verification of uptake into target cells, and limited assay-specific methods alterations to avoid interference with uptake or endpoint analysis. These recommendations are summarized in a Roadmap guideline for testing.
The study of intelligence in humans has been ongoing for over 100 years, including the underlying structure, predictive validity, related cognitive measures, and source of differences. One of the key ...findings in intelligence research is the uniform positive correlations among cognitive tasks. This has been replicated with every cognitive test battery in humans. Nevertheless, many other aspects of intelligence research have revealed contradictory lines of evidence. Recently, cognitive test batteries have been developed for animals to examine similarities to humans in cognitive structure. The results are inconsistent, but there is evidence for some similarities. This article reviews the way intelligence and related cognitive abilities are assessed in humans and animals and suggests a different way of devising test batteries for maximizing between-species comparisons.
Public Significance Statement
This review highlights the difficulty in understanding why different cognitive abilities are related to each other in human and nonhuman animals. Cognitive abilities are related in similar ways across species, but test batteries should be refined to strengthen these findings and increase translational significance.
Inhibitory control, the ability to overcome prepotent but ineffective behaviors, has been studied extensively across species, revealing the involvement of this ability in many different aspects of ...life. While various different paradigms have been created in order to measure inhibitory control, only a limited number of studies have investigated whether such measurements indeed evaluate the same underlying mechanism, especially in non-human animals. In humans, inhibitory control is a complex construct composed of distinct behavioral processes rather than of a single unified measure. In the current study, we aimed to investigate the validity of inhibitory control paradigms in dogs. Sixty-seven dogs were tested in a battery consisting of frequently used inhibitory control tests. Additionally, dog owners were asked to complete an impulsivity questionnaire about their dog. No correlation of dogs' performance across tasks was found. In order to understand whether there are some underlying behavioral aspects explaining dogs' performance across tests, we performed principle component analyses. Results revealed that three components (persistency, compulsivity and decision speed) explained the variation across tasks. The questionnaire and dogs' individual characteristics (i.e., age and sex) provided only limited information for the derived components. Overall, results suggest that no unique measurement for inhibitory control exists in dogs, but tests rather measure different aspects of this ability. Considering the context-specificity of inhibitory control in dogs and most probably also in other non-human animals, extreme caution is needed when making conclusions about inhibitory control abilities based on a single test.
Our laboratory uses a specific test battery for the initial assessment of phenotypic behavioral differences of transgenic, knockout, and inbred strains of mice. Our standard battery includes: open ...field activity, light–dark exploration, rotarod, prepulse inhibition (PPI), acoustic startle habituation, conditioned fear, Morris water maze, and hot plate. Tests are run in the order listed, from least invasive to most invasive, to decrease the chance that behavioral responses are altered by prior test history. The studies presented here were designed around two questions. The first study asks if differences exist between mice that have undergone testing on different tasks and mice that are naı̈ve to the test experience. The second study asks if the test order affects how an animal performs on subsequent tests. In the first experiment, C57BL/6J male mice were evaluated on all of the tests described above. The behavior of these ‘test battery’ mice was compared to aged matched naı̈ve mice that were only tested on one test from the battery. Results indicate that on some tests, the behavior of ‘test battery’ mice was significantly different from the behavior of naı̈ve mice, while on other tests there were no differences. For example, test battery mice responded differently in the open-field, rotarod, and hot-plate test, but behaved similar on the PPI and conditioned fear. Experiments in the second study were performed on male 129/SvEvTac (129S6) and C57BL/6J male mice. An abbreviated battery of tasks was used and the results suggest that certain test variables are sensitive to test order, whereas others are resistant. These two studies demonstrate that some behavioral tests appear to be sensitive to previous testing experience, while other tests are immune.
Recent acceleration in development of computerized neuropsychological tests and test batteries has led to gains in sophistication, intuitiveness, and capability with concomitant opportunities for ...greater adoption among practitioners. Advantages attributed to computerized methods (e.g., standardization, large-scale screening, measurement of performance attributes inaccessible by traditional means) enhance prospects for growth. Despite technological improvement and potential benefit to neuropsychological assessment, the regularity with which neuropsychologists utilize computer-based methods remains unsettled. As part of a 10-year follow-up study of neuropsychological test usage practices, we surveyed neuropsychologists' utilization of computerized instruments and investigated practice-related factors that influence computerized test adoption. Respondents were 512 doctorate-level psychologists residing in the United States and Canada (26% usable response rate; 54% female) affiliated with the National Academy of Neuropsychology or the International Neuropsychological Society. Of the 693 distinct instruments reported by respondents, only 6% (n = 40) were computerized, and the average respondent reported rarely using computerized tests. We present the top-ranked computerized instruments and results of correlational analyses, which indicate that fewer years practicing and the youth of respondents associates with increased likelihood of computerized test utilization, along with increased utilization of neuropsychological tests with alternative or parallel forms. Implications for existing and emerging technologies in research and clinical settings are considered.
By 2.5 years of age humans are more skilful than other apes on a set of social, but not nonsocial, cognitive tasks. Individual differences in human infants, but not chimpanzees, Pan troglodytes, are ...also explained by correlated variance in these cooperative communicative skills. Relative to nonhuman apes, domestic dogs, Canis familiaris, perform more like human infants in cooperative communicative tasks, but it is unknown whether dog and human cognition share a similar underlying structure. We tested 552 dogs in a large-scale test battery modelled after similar work with humans and nonhuman apes. Unlike chimpanzees, but similarly to humans, individual differences in dogs were explained by correlated variance in skills for solving cooperative communicative problems. Direct comparisons of data from all three species revealed similar patterns of individual differences in cooperative communication between human infants (N=105) and domestic dogs (N=430), which were not observed in chimpanzees (N=106). Future research will be needed to examine whether the observed similarities are a result of similar psychological mechanisms and evolutionary processes in the dog and human lineages.
•We assessed individual differences in cognition in dogs, chimpanzees and human infants.•Dogs and humans exhibited similar patterns of correlation in social cognitive skills.•The patterns common to dogs and humans were not observed in chimpanzees.•Results were similar for three different dog populations with diverse histories.•The structure of dog social cognition may be convergent with that of humans.
This study investigated the effect of a 10-week karate training program on the motor skill development of 5-7-year-old children new to karate with two different test batteries. A total of 28 ...participants were included in the study: 18 in the Karate group and 10 in the control group. The karate group was subjected to a fundamental karate training (kihon) program consisting of 90-minute sessions four days a week for ten weeks in addition to physical education classes at their schools. In contrast, the control group did not participate in any sportive activities except physical education classes in their schools. Data were collected using the Eurofit test battery and the TGMD-2 test. In the pre-post test comparison of the anthropometric measurements of the karate group, no significant difference was found in the control group. In contrast, a significant difference was obtained in height, body mass index, and body fat percentage. In the post-test analysis of the two independent groups, there were statistically significant differences in favor of the karate group regarding height and body fat percentage (
< 0.005). In the pre-post analysis of the Eurofit test and the TGMD-2 for the karate group, all parameters showed statistically significant improvements (
< 0.001), while the control group showed no statistical difference. After comparing the karate and control groups, the Eurofit Test and TGMD-2 post-test results showed significantly higher scores (statistically significant differences) in all parameters for the karate group. In conclusion, the study shows that the 10-week karate training program positively affected the motor development of the participating children.
In human psychometric testing, individuals' scores in tests of diverse cognitive processes are positively correlated, with a ‘general intelligence’ factor (g) typically accounting for at least 40% of ...total variance. Individual differences in cognitive ability have been extensively studied in humans, yet they have received far less attention in nonhuman animals. In particular, the development of a test battery suitable for quantifying individual cognitive performance in birds remains in its infancy. Additionally, implementing this approach in the wild, where the ecological significance of cognition can also be explored, presents considerable logistical challenges for most species. We developed a cognitive test battery for wild New Zealand North Island robins. Our battery comprised six tasks based on established measures of avian cognitive performance: a motor task, colour and shape discrimination, reversal learning, spatial memory and inhibitory control. Robins varied greatly in their ability to solve these tasks and we found weakly positive, nonsignificant correlations between most tasks. A principal components analysis of task performances yielded two factors with eigenvalues >1. The first component extracted explained over 34% of the variance in cognitive performance and all six tasks loaded positively on this first component. We show, using randomization tests, that these results are robust. Our results thus suggest that a general cognitive factor, analogous to human g, underpins cognitive performance in wild North Island robins tested in their natural habitat.
•We developed a cognitive test battery for wild New Zealand robins, Petroica longipes.•Robins varied greatly in their cognitive performance in the six test battery tasks.•A general cognitive factor, analogous to human g, underpinned task performance.•This is the first evidence that a g factor may exist in a food-caching species.
Aging is considered to be associated with progressive changes in the brain and its associated sensory, motor, and cognitive functions. A large number of studies comparing young and aged animals have ...reported differences in various behaviors between age-cohorts, indicating behavioral dysfunctions related to aging. However, relatively little is known about behavioral changes from young adulthood to middle age, and the effect of age on behavior during the early stages of life remains to be understood. In order to investigate age-related changes in the behaviors of mice from young adulthood to middle age, we performed a large-scale analysis of the behavioral data obtained from our behavioral test battery involving 1739 C57BL/6J wild-type mice at 2-12 months of age.
Significant behavioral differences between age groups (2-3-, 4-5-, 6-7-, and 8-12-month-old groups) were found in all the behavioral tests, including the light/dark transition, open field, elevated plus maze, rotarod, social interaction, prepulse inhibition, Porsolt forced swim, tail suspension, Barnes maze, and fear conditioning tests, except for the hot plate test. Compared with the 2-3-month-old group, the 4-5- and 6-7-month-old groups exhibited decreased locomotor activity to novel environments, motor function, acoustic startle response, social behavior, and depression-related behavior, increased prepulse inhibition, and deficits in spatial and cued fear memory. For most behaviors, the 8-12-month-old group showed similar but more pronounced changes in most of these behaviors compared with the younger age groups. Older groups exhibited increased anxiety-like behavior in the light/dark transition test whereas those groups showed seemingly decreased anxiety-like behavior measured by the elevated plus maze test.
The large-scale analysis of behavioral data from our battery of behavioral tests indicated age-related changes in a wide range of behaviors from young adulthood to middle age in C57BL/6J mice, though these results might have been influenced by possible confounding factors such as the time of day at testing and prior test experience. Our results also indicate that relatively narrow age differences can produce significant behavioral differences during adulthood in mice. These findings provide an insight into our understanding of the neurobiological processes underlying brain function and behavior that are subject to age-related changes in early to middle life. The findings also indicate that age is one of the critical factors to be carefully considered when designing behavioral tests and interpreting behavioral differences that might be induced by experimental manipulations.
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