Associative learning performance is impaired in zebrafish (Danio rerio) by the NMDA-R antagonist MK-801

The zebrafish is gaining popularity in behavioral neuroscience perhaps because of a promise of efficient large scale mutagenesis and drug screens that could identify a substantial number of yet undiscovered molecular players involved in complex traits. Learning and memory are complex functions of the brain and the analysis of their mechanisms may benefit from such large scale zebrafish screens. One bottleneck in this research is the paucity of appropriate behavioral screening paradigms, which may be due to the relatively uncharacterized nature of the behavior of this species. Here we show that zebrafish exhibit good learning performance in a task adapted from the mammalian literature, a plus maze in which zebrafish are required to associate a neutral visual stimulus with the presence of conspecifics, the rewarding unconditioned stimulus. Furthermore, we show that MK-801, a non-competitive NMDA-R antagonist, impairs memory performance in this maze when administered right after training or just before recall but not when given before training at a dose that does not impair motor function, perception or motivation. These results suggest that the plus maze associative learning paradigm has face and construct validity and that zebrafish may become an appropriate and translationally relevant study species for the analysis of the mechanisms of vertebrate, including mammalian, learning and memory.     

The use of visual and automatized behavioral markers to assess methodologies: a study case on PIT-tagging in the Alpine newt

In various research fields, biomarkers are now widely used as tools for assessing individual integrity. The recent advances in quantification methods for behavioral patterns, such as computerized video-tracking procedures, make them valuable biomarkers. However, the corollary of these novelties is that they remain relatively unknown and unused. In this study, we show that such tools can assess the validity of research methods, such as individual recognition. To demonstrate this, we employed, as a model, a marking method (passive integrated transponder [PIT] tagging) widely used in amphibians. Detailed visual observations and video-tracking methods were complementary in highlighting components at different behavioral scales: locomotion, feeding, and breeding. We illustrate the scientific and ethical adequacy of the targeted marking method but also suggest that more studies should integrate behavioral analyses. Such biomarkers are a powerful tool for assessing conservation concerns when other techniques cannot detect detrimental effects.     

How different is a 3D‐printed replica from a conspecific in the eyes of a zebrafish?

Robotics is emerging as a promising tool for aiding research on animal behavior. The possibility of generating customizable, controllable, and standardized robotic stimuli has been demonstrated through a number of behavioral assays, involving vertebrates and invertebrates. However, the specific appraisal of the nature of robotic stimuli is currently lacking. Here, we attempt to evaluate this aspect in zebrafish, through a within‐subject design in which experimental subjects are faced with three experimental conditions. In the first test, we investigated sociability by measuring zebrafish response to a conspecific separated by a one‐way glass. In the second test, we studied zebrafish behavior in response to a 3D‐printed zebrafish replica actuated along realistic trajectories through a novel four‐degree‐of‐freedom robotic platform. Last, we investigated fear responses in a shelter‐seeking test. In agreement with our expectations, zebrafish exhibited an equivalent preference for live and robotic stimuli, and the degree of preference for the robotic replica correlated negatively with the individual propensity to seek shelter. The equivalent preference for the replica and conspecific suggests that the appraisal of the target stimuli is analogous. The preliminary evidence of a correlation between behavioral responses across tests points to the readability of robotics‐based approaches to investigate interindividual differences.     

Establishing and maintaining a low-cost zebrafish breeding and behavioral research facility

The purpose of this paper is to describe how to establish and maintain a low-cost zebrafish facility that can be used for both teaching and research purposes. The cost of the facility ranges from about 250 to250 to 1,000, depending on the size of the facility and the experiments that will be conducted. The facility plan presented here also has the advantage that it can be disassembled so that it need not function year-round. A detailed list of supplies and materials is provided, along with detailed instructions on how to set up and maintain the adult and breeding portions of the facility. Finally, there is discussion of some of the general uses of a zebrafish facility, including a variety of procedures that are currently being used in behavioral research with this species.     

Zebrafish prefer larger to smaller shoals: analysis of quantity estimation in a genetically tractable model organism

Numerical abilities have been demonstrated in a variety of non-human vertebrates. However, underlying biological mechanisms have been difficult to study due to a paucity of experimental tools. Powerful genetic and neurobiological tools already exist for the zebrafish, but numerical abilities remain scarcely explored with this species. Here, we investigate the choice made by single experimental zebrafish between numerically different shoals of conspecifics presented concurrently on opposite sides of the experimental tank. We examined this choice using the AB strain and pet store zebrafish. We found zebrafish of both populations to generally prefer the numerically larger shoal to the smaller one. This preference was significant for contrasted ratios above or equalling 2:1 (i.e. 4 vs. 0, 4 vs. 1, 8 vs. 2, 6 vs. 2 and 6 vs. 3). Interestingly, zebrafish showed no significant preference when each of the two contrasted shoals had at least 4 members, e.g. in a contrast 8 versus 4. These results confirm that zebrafish possess the ability to distinguish larger numbers of items from smaller number of items, in a shoaling context, with a potential limit above 4. Our findings confirm the utility of the zebrafish for the exploration of both the behavioural and the biological mechanisms underlying numerical abilities in vertebrates.     

The roots of territorial marking in the Mongolian gerbil: A problem of species-common topography

The Mongolian gerbil (Meriones unguiculatus) has recently been introduced into behavioral research. Many features make it an ideal laboratory animal. It is docile, highly exploratory, a good learner, virtually odorless and can be maintained without water; other than that it metabolizes from its food. General characteristics of the gerbil are described, and a brief review of behavioral research is given. The gerbil also possesses unique attributes that can only be studied by matching experimental methodology with species-common responses. Territorial marking is used as example. The gerbil regularly marks objects in an open field by skimming the object with a midventral sebaceous scent gland. The marking and gland are dimorphic, with the male marking about twice as frequently as the female and possessing a gland roughly twice the size. The configuration of the field (object quality) modifies the frequency of the response, as does the time of day the animals are exposed to the field. Androgen levels control the level of marking in the male and female, and the correlations between testis weight, size of the sebaceous gland, secretory output and marking frequency are significant. When a gerbil is introduced into an open field recently contaminated by another gerbil, or when objects are smeared with sebum and placed in the field, the male tends to be more hesitant in several types of behavior. The laboratory measures are internally consistent and congruous with the notion that natural selection has acted to reinforce a hormone-behavior relation of social significance to the gerbil.     

Preschool children’s interpretation of object‐initial sentences: Neural correlates of their behavioral performance

The acquisition of the function of case‐marking is a key step in the development of sentence processing for German‐speaking children since case‐marking reveals the relations between sentential arguments. In this study, we investigated the development of the processing of case‐marking and argument structures in children at 3, 4;6 and 6 years of age, as well as its processing in adults. Using EEG, we measured event‐related potentials (ERPs) in response to object‐initial compared to subject‐initial German sentences including transitive verbs and case‐marked noun phrases referring to animate arguments. We also tested children’s behavioral competence in a sentence‐picture matching task. Word order and case‐marking were manipulated in German main clauses. Adults’ behavioral performance was close to perfect and their ERPs revealed a negativity for the processing of the topicalized accusative marked noun phrase (NP1) and no effect for the second NP (NP2) in the object‐initial structure. Children’s behavioral data showed a significant above‐chance outcome in the subject‐initial condition for all age groups, but not for the object‐initial condition. In contrast to adults, the ERPs of 3‐year‐olds showed a positivity at NP1, indicating difficulties in processing the non‐canonical object‐initial structures. Children at the age of 4;6 did not differ in the processing patterns of object‐initial vs. subject‐initial sentences at NP1 but showed a slight positivity at NP2. This positivity at NP2, which implies syntactic integration difficulties, is more pronounced in 6‐year‐olds but is absent in adults. At NP1, however, 6‐year‐olds show the same negativity as adults. In sum, the behavioral and electrophysiological findings demonstrate that children in each age group use different strategies, which are indicative of their developmental stage. While 3‐year‐olds merely detect differences in the two sentence structures without being able to use this information for sentence comprehension, 4;6‐year‐olds proceed to use mainly a word‐order strategy, processing NP1 in both conditions in the same manner, which leads to processing difficulties upon detecting case‐marking cues at NP2. At the age of 6, children are able to use case‐marking cues for comprehension but still show enhanced effort for correct thematic‐role assignment.     

Illinois Classroom Assessment Profile: Development of the Instrument

This article describes the development of a teacher rating scale that is sensitive to a select group of behavior disorders exhibited by children in the classroom. The scale, the Illinois Classroom Assessment Profile (ICAP), was developed to distinguish among behavioral dimensions representing sustained attention, impulsivity, conduct, fine motor coordination, and evaluative anxiety. The fact that disorders in these behaviors are observed in children diagnosed as hyperactive has served as the impetus for this research. The ICAP is intended to facilitate research investigating the effects of specific treatments on each of these behavioral dimensions.     

Assessing learning and memory in pigs

In recent years, there has been a surge of interest in (mini) pigs (Sus scrofa) as species for cognitive research. A major reason for this is their physiological and anatomical similarity with humans. For example, pigs possess a well-developed, large brain. Assessment of the learning and memory functions of pigs is not only relevant to human research but also to animal welfare, given the nature of current farming practices and the demands they make on animal health and behavior. In this article, we review studies of pig cognition, focusing on the underlying processes and mechanisms, with a view to identifying. Our goal is to aid the selection of appropriate cognitive tasks for research into pig cognition. To this end, we formulated several basic criteria for pig cognition tests and then applied these criteria and knowledge about pig-specific sensorimotor abilities and behavior to evaluate the merits, drawbacks, and limitations of the different types of tests used to date. While behavioral studies using (mini) pigs have shown that this species can perform learning and memory tasks, and much has been learned about pig cognition, results have not been replicated or proven replicable because of the lack of validated, translational behavioral paradigms that are specially suited to tap specific aspects of pig cognition. We identified several promising types of tasks for use in studies of pig cognition, such as versatile spatial free-choice type tasks that allow the simultaneous measurement of several behavioral domains. The use of appropriate tasks will facilitate the collection of reliable and valid data on pig cognition.     

Safety at first sight? – Manual drivers’ experience and driving behavior at first contact with Level 3 vehicles in mixed traffic on the highway

Soon, manual drivers will interact with conditionally automated vehicles (CAVs; SAE Level 3) in a mixed traffic on highways. As of yet, it is largely unclear how manual drivers will perceive and react to this new type of vehicle. In a driving simulator study with N = 51 participants aged 20 to 71 years (22 female), we examined the experience and driving behavior of manual drivers at first contact with Level 3 vehicles in four realistic driving scenarios (highway entry, overtaking, merging, introduction of a speed limit) that Level 3 vehicles may handle alone once their operational domain extends beyond driving in congested traffic. We also investigated the effect of an external marking via a visual external human–machine interface (eHMI), with participants being randomly assigned to one of three experimental groups (none, correct, incorrect marking). Participants experienced each driving scenario four times, twice with a human-driven vehicle (HDV), and twice with a CAV. After each interaction, participants rated perceived driving mode of the target vehicle as well as perceived safety and comfort. Minimum time headways between participants and target vehicles served as an indicator of safety criticality in the interactions. Results showed manual driver can distinguish CAVs from HDVs based on behavioral differences. In all driving scenarios, participants rated interactions with CAVs at least as safe as interactions with HDVs. The driving data analysis showed that manual driver interactions with CAVs were largely uncritical. However, the CAVs’ strict rule-compliance led to short time headways of following manual drivers in some cases. The eHMI used in this study neither affected the subjective ratings of the manual drivers nor their driving behavior in mixed traffic. Thus, the results do not support the use of eHMIs on the highway, at least not for the eHMI design used in this study.     

Heterosexual Identity Management: How Social Context Affects Heterosexual Marking Practices

It is well established that heterosexism shapes identity management practices of sexual minorities in the United States, but we know little about how such social forces shape heterosexual identity management. This exploratory research is focused on heterosexual marking, defined as behaviors interpreted as signifying a heterosexual identity. Using data from 12 focus groups with young adults, we provide an overview of heterosexual marking in a northeastern United States context and explain how three social forces—cultural assumptions of heterosexuality, sexual orientation ambiguity and suspicion, and heterosexism—are intertwined with these identity practices. Results indicated that this social context generates heterosexual marking that is sometimes intentional and conscious but at other times unintentional and unconscious, depending on levels of heteronormativity and heterosexism.     

Consistent Treatment of Variables and Causation Poses a Challenge for Behavioral Research Methods: A Commentary on Nesselroade and Molenaar (2016)

Nesselroade and Molenaar presented the ideographic filter as a proposal for analyzing lawful regularities in behavioral research. The proposal highlights an inconsistency that poses a challenge for behavioral research more generally. One can distinguish a broadly Humean approach from a broadly non-Humean approach as they relate to variables and to causation. Nesselroade and Molenaar rejected a Humean approach to latent variables that characterizes them as nothing more than summaries of their manifest indicators. By contrast, they tacitly accepted a Humean approach to causes characterized as nothing more than summaries of their manifest causal effects. A non-Humean treatment of variables coupled with a Humean treatment of causation creates a theoretical tension within their proposal. For example, one can interpret the same model elements as simultaneously representing both variables and causes. Future refinement of the ideographic filter proposal to address this tension could follow any of a number of strategies.     

Theoretical and methodological considerations for the study of imagery in animals

Transformation of a moving stimulus is an operational definition of imagery that is useful in animal research. This definition was developed from structural, functional, and interactive theories of imagery in humans. The historical roots of the definition are traced to behavioristic methodologies within cognitive psychology. An imagery procedure for animals was developed that tests this definition with extrapolated movement. Pigeons were reinforced for discriminating between a rectangle that rotated at constant velocity from a rectangle whose final location violated constant velocity. Imagery trials included a short-term memory component in which the task of the pigeon was to discriminate between extrapolated trajectories of rotation while the rectangle was absent. The evidence supports similarities between human and animal representations of movement. A visible transformation employed as a sample stimulus and followed by a retention interval provides a powerful procedure for measuring the interaction between perception and memory. An advantage of this paradigm is that it could be employed to investigate imagery at the neural level or to obtain comparative behavioral data from different species.     

一种自上而下加工的注意选择新机制:视觉标记

视觉标记是国外新近提出的有关注意选择机制的一种假设。该假设认为,在任务目标预先设定的条件下视觉系统是通过抑制旧刺激所处的位置来实现对新刺激的优先选择。本文主要介绍了视觉标记研究的经典实验范式、视觉标记理论的行为实验依据和脑成像实验依据,还概述了三种质疑视觉标记理论的观点。最后对视觉标记的未来研究做了展望。     

EthoSeq: A tool for phylogenetic analysis and data mining in behavioral sequences

This article introduces the software program called EthoSeq, which is designed to extract probabilistic behavioral sequences (tree-generated sequences, or TGSs) from observational data and to prepare a TGS-species matrix for phylogenetic analysis. The program uses Graph Theory algorithms to automatically detect behavioral patterns within the observational sessions. It includes filtering tools to adjust the search procedure to user-specified statistical needs. Preliminary analyses of data sets, such as grooming sequences in birds and foraging tactics in spiders, uncover a large number of TGSs which together yield single phylogenetic trees. An example of the use of the program is our analysis of felid grooming sequences, in which we have obtained 1,386 felid grooming TGSs for seven species, resulting in a single phylogeny. These results show that behavior is definitely useful in phylogenetic analysis. EthoSeq simplifies and automates such analyses, uncovers much of the hidden patterns of long behavioral sequences, and prepares this data for further analysis with standard phylogenetic programs. We hope it will encourage many empirical studies on the evolution of behavior.     

Shades of support: An empirical assessment of D&I policy support in organizations

In this research, we aim to develop a better understanding of the different ways in which employees can advance or resist the diversity and inclusion (D&I) policies implemented by their organization. To this end, we complement prior work by distinguishing between employees' attitudinal and behavioral opposition versus support for D&I policies. We combine these to distinguish different combinations of attitudinal and behavioral responses that characterize specific groups of employees, which we label opponents, bystanders, reluctants, and champions. In a large-scale survey study conducted among employees from seven organizations located in the Netherlands (n = 2913), we find empirical support for the validity of this taxonomy and its value in understanding the likelihood that employees advance or resist D&I policies. Furthermore, we find more convergence between attitudinal and behavioral support when employees perceive a more positive climate for inclusion. Together, these results advance existing scholarly work by providing both a theoretical account of and empirical evidence for the different ways in which D&I policies may find support or resistance from employees. In addition, our work offer practitioners a practical tool to examine the likelihood that D&I policies meet support or opposition from their employees and therefore enables them to design and implement more effective D&I interventions.     

A one-trial inhibitory avoidance task to zebrafish: Rapid acquisition of an NMDA-dependent long-term memory

The behavioral tasks aiming to evaluate learning and memory mechanisms currently available to zebrafish (Danio rerio) involve long training sessions frequently along multiple days and are based on shuttle box or active-avoidance protocols, preventing a detailed analysis of cellular and molecular time-dependent processes involved in memory acquisition and consolidation. In order to explore zebrafish’s potential contribution to the characterization of the molecular machinery underlying learning and memory rapidly acquired and reliable paradigms are necessary. In this study we present a rapid and effective learning protocol in a single-trial inhibitory avoidance in zebrafish. In a simple apparatus, adult animals learned to refrain from swimming from a white into a dark compartment in order to avoid an electric shock during a single-trial training session that lasted less than 2 min. The resulting memory is robust, long-lasting and sensitive to NMDA-receptor antagonist MK-801 given in the tank water immediately after training. Experiments aiming to further characterize the events underlying memory formation, retrieval or extinction or those looking for cognitive profiling of mutants, neurotoxicological studies and disease models may benefit from this task, and together with complementary strategies available for zebrafish may significantly improve our current knowledge on learning and memory mechanisms.     

Age-related impairment in the 250-millisecond delay eyeblink classical conditioning procedure in C57BL/6 mice

In this study we tested 4-, 9-, 12-, and 18-month-old C57BL/6 mice in the 250-msec delay eyeblink classical conditioning procedure to study age-related changes in a form of associative learning. The short life expectancy of mice, complete knowledge about the mouse genome, and the availability of transgenic and knock-out mouse models of age-related impairments make the mouse an excellent species for expanding knowledge on the neurobiologically and behaviorally well-characterized eyeblink classical conditioning paradigm. Based on previous research with delay eyeblink conditioning in rabbits and humans, we predicted that mice would be impaired on this cerebellar-dependent associative learning task in middle-age, at ~9 months. To fully examine age differences in behavior in mice, we used a battery of additional behavioral measures with which to compare young and older mice. These behaviors included the acoustic startle response, prepulse inhibition, rotorod, and the Morris water maze. Mice began to show impairment in cerebellar-dependent tasks such as rotorod and eyeblink conditioning at 9 to 12 months of age. Performance in hippocampally dependent tasks was not impaired in any group, including 18-month-old mice. These results in mice support results in other species, indicating that cerebellar-dependent tasks show age-related deficits earlier in adulthood than do hippocampally dependent tasks.     

The Behavioral and Pharmacological Actions of NMDA Receptor Antagonism are Conserved in Zebrafish Larvae

Dizocilpine maleate (MK-801) is one of several NMDA receptor antagonists that is widely used to pharmacologically model the symptoms of psychosis and schizophrenia in animals. MK-801 elicits behaviors in adult zebrafish (Danio rerio) that are phenotypically consistent with behaviors observed in humans and rodents exposed to tbhe drug. However, the molecular and cellular processes that mediate the psychotomimetic, cognitive and locomotive behaviors of MK-801 are unclear. We exposed zebrafish larvae to MK-801 to assess their merit as a model organism to elucidate the behavioral effects of NMDA receptor blockade. Zebrafish larvae were acutely immersed in MK-801 to assess the effect on spontaneous swimming. MK-801 caused a time- and dose-dependent increase in larval swim speed, and the peak response (a five-fold increase in swim speed) was evoked by a three h exposure to a 20 uM dose. Zebrafish larvae did not exhibit sensitivity to the locomotor effects of MK-801 until 5 dpf, suggesting a critical role for developmental in sensitivity to the drug. Exposure to the low potency NMDA antagonist, memantine, did not alter the swim speed of zebrafish larvae. Co-immersion in D(1) or D(2) dopamine receptor antagonists did not disrupt the time course or magnitude of the increase in swim speed, suggesting dopaminergic signaling is not required for the locomotor actions of MK-801. Our findings of the behavioral actions of MK-801 in zebrafish larvae are consistent with previous observations in mammals and imply that the physiological, cellular and molecular processes disrupted by MK-801 are conserved in zebrafish larvae. These data suggest that the zebrafish larvae is a valid and useful model to elucidate neurobehavioral aspects of NMDA receptor antagonism and may provide insight to the neurobiology of psychosis and schizophrenia.     

Varieties of preschool hyperactivity: multiple pathways from risk to disorder

In this paper we examine the characteristics of preschool attention deficit hyperactivity disorder (ADHD) from both mental disorder and developmental psychopathology points of view. The equivalence of preschool and school-aged hyperactivity as a behavioral dimension is highlighted together with the potential value of extending the use of the ADHD diagnostic category to the preschool period where these behaviours take an extreme and impairing form (assuming age appropriate diagnostic items and thresholds can be developed). At the same time, the importance of identifying pathways between risk and later ADHD is emphasized. Developmental discontinuity and heterogeneity are identified as major characteristics of these pathways. We argue that models that distinguish among different developmental types of early-emerging problems are needed. An illustrative taxonomy of four developmental pathways implicating preschool hyperactivity is presented to provide a framework for future research.