What do zebrafish prefer? Directional and color preferences in maze tasks

Studies regarding the animals innate preferences help elucidate and avoid probable sources of bias and serve as a reference to improve and develop new behavioral tasks. In zebrafish research, the results of innate directional and color preferences are often not replicated between research groups or even inside the same laboratory raising huge concerns on the replicability and reproducibility. Thus, this study aimed to investigate the male and female zebrafish innate directional and color preferences in the plus-maze and T-maze behavioral tasks. As revealed by the percentage of time spent in each zone of the maze, our results showed that males and females zebrafish demonstrated no difference in directional preference in the plus-maze task. Surprisingly, male and female zebrafish showed color preference differences in the plus-maze task; males did not show any color preference, while female zebrafish demonstrated a red preference compared to white, blue, and yellow colors. Moreover, both male and female zebrafish demonstrated a strong black color preference compared to the white color in the T-maze task. Thus, our results demonstrate the importance of innate preference assays involved with the directionality of the apparatus or the application of colors as a screening process conducting behavioral tests (e.g., anxiety, learning and memory assessment, locomotion, and preference) and highlight the need to analyze sex differences.

The Nanotheranostic Researcher’s Guide for Use of Animal Models of Traumatic Brain Injury

Traumatic brain injury (TBI) is currently the leading cause of injury-related morbidity and mortality worldwide, with an estimated global cost of USD 400 billion annually. Both clinical and preclinical behavioral outcomes associated with TBI are heterogeneous in nature and influenced by the mechanism and frequency of injury. Previous literature has investigated this relationship through the development of animal models and behavioral tasks. However, recent advancements in these methods may provide insight into the translation of therapeutics into a clinical setting. In this review, we characterize various animal models and behavioral tasks to provide guidelines for evaluating the therapeutic efficacy of treatment options in TBI. We provide a brief review into the systems utilized in TBI classification and provide comparisons to the animal models that have been developed. In addition, we discuss the role of behavioral tasks in evaluating outcomes associated with TBI. Our goal is to provide those in the nanotheranostic field a guide for selecting an adequate TBI animal model and behavioral task for assessment of outcomes to increase research in this field.

Three water restriction schedules used in rodent behavioral tasks transiently impair growth and differentially evoke a stress hormone response without causing dehydration

Water restriction is commonly used to motivate rodents to perform behavioral tasks; however, its effects on hydration and stress hormone levels are unknown. Here, we report daily body weight and bi-weekly packed red blood cell volume and corticosterone in adult male rats across 80 days for three commonly used water restriction schedules. We also assessed renal adaptation to water restriction using post-mortem histological evaluation of renal medulla. A control group received ad libitum water. After one week of water restriction, rats on all restriction schedules resumed similar levels of growth relative to the control group. Nominal hydration was observed, and water restriction did not drive renal adaptation. An intermittent restriction schedule was associated with an increase in corticosterone relative to the control group. Our results suggest that the water restriction schedules used here will maintain welfare in rats. However, intermittent restriction evokes a stress response which could affect behavioral and neurobiological results. Our results also suggest that stable motivation in behavioral tasks may only be achieved after one week of restriction.

The zebrafish (Danio rerio) anxiety test battery: comparison of behavioral responses in the novel tank diving and light–dark tasks following exposure to anxiogenic and anxiolytic compounds

Rationale Triangulation of approaches (i.e., using several tests of the same construct) can be extremely useful for increasing the robustness of the findings being widely used when working with behavioral testing, especially when using rodents as a translational model. Although zebrafish are widely used in neuropharmacology research due to their high-throughput screening potential for new therapeutic drugs, behavioral test battery effects following pharmacological manipulations are still unknown. Methods Here, we tested the effects of an anxiety test battery and test time following pharmacological manipulations in zebrafish by using two behavioral tasks: the novel tank diving task (NTT) and the light–dark test (LDT). Fluoxetine and conspecific alarm substance (CAS) were chosen to induce anxiolytic and anxiogenic-like behavior, respectively. Results For non-drug-treated animals, no differences were observed for testing order (NTT → LDT or LDT → NTT) and there was a strong correlation between performances on the two behavioral tasks. However, we found that during drug treatment, NTT/LDT responses are affected by the tested order depending on the test time being fluoxetine effects higher at the second behavioral task (6 min later) and CAS effects lower across time. Conclusions Overall, our data supports the use of baseline behavior assessment using this anxiety test battery. However, when working with drug exposure, data analysis must carefully consider time-drug-response and data variability across behavioral tasks.

Effort and delay influence choices about relief

Relief from aversive states/contexts is among the most common motivators of behavior. Relative to reward-seeking behavior, however, relief-seeking behavior has received little scientific attention, and basic questions about the motivating properties of relief remain unanswered. Prior research has demonstrated that people prefer smaller rewards if they require less effort and less delay (i.e., wait time) than larger rewards, a tendency known as discounting. Here we asked whether effort and delay similarly influence choices about relief. To answer this question, we recruited 43 adults to complete two novel behavioral tasks designed to index tradeoffs between the cost of effort or delay, and the benefit of relief. We then compared the fit of a series of mathematical discount functions to participants’ choices in each task to identify how increased effort or delay leads to a discounted value of relief. Results suggest that the value of relief is discounted as a function of increasing effort and increasing delay. We further found that, similar to prior research on rewards, a parabolic discount model best accounted for the tradeoff between effort and relief. However, unlike previous findings on reward, a linear discount model best accounted for the tradeoff between delay and relief. Our results demonstrate that effort and delay are costs that influence choices about relief and also identify best-fitting discount models that can be used by future studies of relief-based decisions.

A common computational principle for vibrotactile pitch perception in mouse and human

We live surrounded by vibrations generated by moving objects. These oscillatory stimuli propagate through solid substrates, are sensed by mechanoreceptors in our body and give rise to perceptual attributes such as vibrotactile pitch (i.e. the perception of how high or low a vibration’s frequency is). Here, we establish a mechanistic relationship between vibrotactile pitch perception and the physical properties of vibrations using behavioral tasks, in which vibratory stimuli were delivered to the human fingertip or the mouse forelimb. The resulting perceptual reports were analyzed with a model demonstrating that physically different combinations of vibration frequencies and amplitudes can produce equal pitch perception. We found that the perceptually indistinguishable but physically different stimuli follow a common computational principle in mouse and human. It dictates that vibrotactile pitch perception is shifted with increases in amplitude toward the frequency of highest vibrotactile sensitivity. These findings suggest the existence of a fundamental relationship between the seemingly unrelated concepts of spectral sensitivity and pitch perception.

The Relationship between Bipolar and Borderline Personality Disorder traits, Impulsivity, and GPA among a college student population

Background: Impulsivity as a multidimensional construct is commonly linked with a wide range of mental health disorders, such as Bipolar Disorder (BD) and Borderline Personality Disorder (BorPD). Previous research suggests that individuals with BD and BorPD are more likely to be associated with lower academic achievement. This experiment aims to investigate the interrelation between BD or BorPD traits, impulsivity, and poor academic performance (GPA). Method: Our pre-registered study tested bipolar and borderline personality traits from a sample of 125 college students. Two behavioral tasks (Two-choice impulsivity paradigm; Go/no-go) and a self-report questionnaire (Barratt Impulsiveness Scale, BIS-11) were used to measure impulsivity. Students’ Grade Point Averages (GPAs) were also collected. Results: Both bipolar and borderline personality traits were positively correlated with the self-report impulsivity questionnaire (BIS-11) but not with the behavioral tasks. Students’ GPA were not significantly correlated with BD, BorPD traits, and impulsivity measures (behavioral and self-report). The self-report impulsivity questionnaire (BIS-11) was only significantly correlated with the Go/no-go task performance, but not the two-choice impulsivity paradigm. Limitations: This study is a correlational study in which participants have pre-existing conditions, therefore we cannot get a causal relationship. Besides, due to the normative sample, the study can only look at traits instead of diagnosis. Conclusions: Results from this study suggest that students with bipolar and/or borderline personality traits tend to have higher self-report impulsivity, without a noticeable impact on their GPA. Our results also support the growing consensus that impulsivity describes a diverse set of processes and traits.