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The remarkable similarities in cognitive performance between teleosts and mammals suggest that the underlying cognitive mechanisms might also be similar in these two groups. We tested this hypothesis by assessing the effects of the brain-derived neurotrophic factor (BDNF), which is critical for mammalian cognitive functioning, on fish's cognitive abilities. We found that individual differences in zebrafish's learning abilities were positively correlated with bdnf expression. Moreover, a CRISPR/Cas9 mutant zebrafish line that lacks the BDNF gene ( bdnf −/− ) showed remarkable learning deficits. Half of the mutants failed a colour discrimination task, whereas the remaining mutants learned the task slowly, taking three times longer than control bdnf +/+ zebrafish. The mutants also took twice as long to acquire a T-maze task compared to control zebrafish and showed difficulties exerting inhibitory control. An analysis of habituation learning revealed that cognitive impairment in mutants emerges early during development, but could be rescued with a synthetic BDNF agonist. Overall, our study indicates that BDNF has a similar activational effect on cognitive performance in zebrafish and in mammals, supporting the idea that its function is conserved in vertebrates.

We tested the hypothesis that part of the gap in numerical competence between fish and warm-blooded vertebrates might be related to the more efficient procedures (e.g. automated conditioning chambers) used to investigate the former and could be filled by adopting an adapted version of the Skinner box in fish. We trained guppies in a visual numerosity discrimination task, featuring two difficulty levels (3 vs. 5 and 3 vs. 4) and three conditions of congruency between numerical and non-numerical cues. Unexpectedly, guppies trained with the automated device showed a much worse performance compared to previous investigations employing more “ecological” procedures. Statistical analysis indicated that the guppies overall chose the correct stimulus more often than chance; however, their average accuracy did not exceed 60% correct responses. Learning measured as performance improvement over training was significant only for the stimuli with larger numerical difference. Additionally, the target numerosity was selected more often than chance level only for the set of stimuli in which area and number were fully congruent. Re-analysis of prior studies indicate that the gap between training with the Skinner box and with a naturalistic setting was present only for numerical discriminations, but not for colour and shape discriminations. We suggest that applying automated conditioning chambers to fish might increase cognitive load and therefore interfere with achievement of numerosity discriminations.

Hidradenitis suppurativa/acne inversa (HS) is one of the most debilitating inflammatory chronic skin diseases and it heavily impairs the emotional and relational life of the patients. Despite its clinical and epidemiological relevance, its psychological correlates are still largely unexplored. The aim of the present study was to investigate the psychological and emotional impact of HS, with a specific focus on psychiatric symptoms, particularly depression, suicidal ideation, self-esteem, anger, and some personality traits. Thirty eight patients diagnosed with HS (HS Group) were compared with a control group of 28 outpatients diagnosed with nevi (N Group) and assessed with psychometric questionnaires (GHQ-28, STAXI-2, BDI-II, BHS, RSES, EF Questionnaire, and I-R Questionnaire). Results showed significant differences between the two groups, with more psychiatric symptoms, lower self-esteem, and higher levels of state anger and of emotional fragility in HS patients. These findings suggest the evidence of a significant psychiatric comorbidity in HS and of a strong emotional impact of the disease.

In a number of species, males and females have different ecological roles and therefore might be required to solve different problems. Studies on humans have suggested that the 2 sexes often show different efficiencies in problem-solving tasks; similarly, evidence of sex differences has been found in 2 other mammalian species. Here, we assessed whether a teleost fish species, the guppy, Poecilia reticulata, displays sex differences in the ability to solve problems. In Experiment 1, guppies had to learn to dislodge a disc that occluded a feeder from which they had been previously accustomed to feed. In Experiment 2, guppies had to solve a version of the detour task that required them to learn to enter a transparent cylinder from the open sides to reach a food reward previously freely available. We found evidence of sex differences in both problem-solving tasks. In Experiment 1, females clearly outperformed males, and in Experiment 2, guppies showed a reversed but smaller sex difference. This study indicates that sex differences may play an important role in fish’s problem-solving similar to what has previously been observed in some mammalian species.

Brain-derived neurotrophic factor (BDNF) plays a pivotal role in neuronal growth and differentiation, neuronal plasticity, learning, and memory. Using CRISPR/ Cas9 technology, we generated a vital Bdnf null mutant line in zebrafish and car- ried out its molecular and behavioral characterization. Although no defects are evident on a morphological inspection, 66% of coding genes and 37% of micro- RNAs turned out to be differentially expressed in bdnf / compared with wild type sibling embryos. We deeply investigated the circadian clock pathway and confirmed changes in the rhythmic expression of clock (arntl1a, clock1a and clock2) and clock-controlled (aanat2) genes. The modulatory role of Bdnf on the zebrafish circadian clock was then validated by behavioral tests highlighting the absence of circadian activity rhythms in bdnf / larvae. The circadian behavior was partially rescued by pharmacological treatment. The bdnf / zebrafish line presented here is the first valuable and stable vertebrate model for the study of BDNF-related neurodevelopmental diseases.

Individual fitness often depends on the ability to inhibit behaviours not adapted to a given situation. However, inhibitory control can vary greatly between individuals of the same species. We investigated a mechanism that might maintain this variability in zebrafish ( Danio rerio ). We demonstrate that inhibitory control correlates with cerebral lateralization, the tendency to process information with one brain hemisphere or the other. Individuals that preferentially observed a social stimulus with the right eye and thus processed social information with the left brain hemisphere, inhibited foraging behaviour more efficiently. Therefore, selective pressures that maintain lateralization variability in populations might provide indirect selection for variability in inhibitory control. Our study suggests that individual cognitive differences may result from complex multi-trait selection mechanisms.

We aimed to evaluate quality of sleep and self-perception risk of medication errors, in a significantly-sized sample of nurses in Italy, using a web survey.An anonymous questionnaire about self-perception of quality of sleep (Pittsburgh Sleep Quality Index - PSQI) and risk of medication errors (based on the 7 R-rule), was made up and delivered by social media, i.e., Facebook and Instagram. Risk of medication errors was intended as near misses, i.e., accidents that do not cause the patient harm.A poor quality of sleep stated by PSQI score5, was present in 87.9% of subjects and the risk of medication errors during the last shift was reported in 76% of them. However, more than half of nurses' sample (60.1%) reported a good or excellent self-perception quality of sleep. Risk of medication errors was associated with poor quality of sleep and it was independently associated with short resting time after night shift and bad self-perception quality of sleep (OR 3.165, 95% CI 1.468-6.827, p=0.003).Absence of proper resting is crucial on performance even if nurses perceived a good quality sleep. The relationship between shift work, poor sleep quality, and risk of medication errors represents crucial point for all health professionals' community, and web-survey represents a valuable information in order to capture the risk of medication errors. Health care organizations should encourage such a type of research in order to show a more proactive approach towards patient safety.

The use of juvenile and larval fish models has been growing in importance for several fields. Accordingly, the evaluation of behavioural tests that can be applied to larvae and juveniles is becoming increasingly important. We tested medaka at four different ages (1, 10, 30, and 120 dph) in the open field test, one of the most commonly used behavioural assays, to investigate its suitability for larvae and juveniles of this species. We also explored ontogenetic variation in behaviour during this test. On average, adult 120-day-old medaka showed higher locomotor activity in terms of distance moved compared with younger fish. Our analysis suggests that this effect was derived from both quantitative changes in locomotion related to the ontogenetic increase in fish size as well as qualitative changes in two aspects of locomotor behaviour. Specifically, time spent moving was similar between 1- and 10-day-old medaka, but progressively increased with development. In addition, we revealed that adult medaka showed constant levels of activity, whereas younger medaka progressively reduced their activity over the course of the entire experiment. The thigmotaxis behaviour typically used to assess anxiety in the open field test emerged at 120 days post-hatching, even though a difference in the temporal pattern of spatial preference emerged earlier, between 10 and 30 days post-hatching. In conclusion, some measures of the open field test such as total distance moved allow behavioural phenotyping in the medaka of all ages, although with some degree of quantitative and qualitative developmental variation. In contrast, immature medaka appear not to exhibit thigmotactic behaviour.

In a number of animal species, individuals differ in their ability to solve cognitive tasks. However, the mechanisms underlying this variability remain unclear. It has been proposed that individual differences in cognition may be related to individual differences in behavior (i.e., personality); a hypothesis that has received mixed support. In this study, we investigated whether personality correlates with the cognitive ability that allows inhibiting behavior in 2 teleost fish species, the zebrafish Danio rerio and the guppy Poecilia reticulata. In both species, individuals that were bolder in a standard personality assay, the open-field test, showed greater inhibitory abilities in the tube task, which required them to inhibit foraging behavior toward live prey sealed into a transparent tube. This finding reveals a relationship between boldness and inhibitory abilities in fish and lends support to the hypothesis of a link between personality and cognition. Moreover, this study suggests that species separated by a relatively large phylogenetic distance may show the same link between personality and cognition, when tested on the same tasks.

We assessed whether zebrafish, Danio rerio, display inhibitory control using a simple and rapid behavioural test. Zebrafish were exposed to a prey stimulus placed inside a transparent tube, which initially elicited attack behaviour. However, zebrafish showed a rapid reduction in the number of attacks towards the prey, which indicated the ability to inhibit their foraging behaviour. Zebrafish also exhibited mnemonic retention of foraging inhibition, as indicated by a reduced number of attacks in a subsequent exposure to the unreachable prey. The ability to inhibit the foraging behaviour varied across three genetically separated wild-type strains and across different individuals within strains, suggesting that zebrafish show heritable within-species differences in inhibitory control. Our behavioural test might be suitable for screening large zebrafish populations in mutational studies and assessing the effects of pharmacologically active substances on inhibitory control.

ispartof: FRONTIERS IN HUMAN NEUROSCIENCE vol:14 ispartof: location:Switzerland status: published