Robert Gerlai

University of Toronto | U of T · Department of Psychology

In this review we discuss the possible utility of zebrafish in research on psilocybin, a psychedelic whose recreational use as well as possible clinical application are gaining increasing interest. First, we review behavioral tests with zebrafish, focussing on anxiety and social behavior, which have particular relevance in the context of psilocybin...

Psychedelic drugs have experienced an unprecedented surge in recreational Highlights use within the past few years. Among recreational users, the risks of psychedelic Psychedelic use is rapidly growing in use by pregnant and breastfeeding women are severely understudied and there popularity for recreational and clinical is little information on the...

Fish are the most species rich and evolutionarily oldest vertebrate taxon. This represents opportunities for biologists who intend to employ laboratory animals in their comparative or translational research. Yet, the overwhelming majority of such studies use a single fish species, the zebrafish, a suboptimal strategy from the comparative standpoint...

Associative learning is often studied using food reward as the unconditioned stimulus (US). With warm-blooded species, to get the subject more motivated the solution has been to feed less, making the subject hungrier. Here we show the opposite with zebrafish. We randomly assigned zebrafish to two groups: a once-a-day-fed and a five-times-a-day-fed...

The dopaminergic neurotransmitter system is implicated in several brain functions and behavioral processes. Alterations in it are associated with the pathogenesis of several human neurological disorders. Pharmacological agents that interact with the dopaminergic system allow the investigation of dopamine-mediated cellular and molecular responses an...

The zebrafish is a laboratory species that gained increasing popularity the last decade in a variety of subfields of biology, including toxicology, ecology, medicine, and the neurosciences. An important phenotype often measured in these fields is behaviour. Consequently, numerous new behavioural apparati and paradigms have been developed for the ze...

The zebrafish has become an important biomedical research organism. In most research applications, zebrafish are removed from their home tank and subsequently their biological features are measured. The method of handling the fish, however, can have significant effects on a variety of biological features. This is particularly problematic for studie...

Alcohol abuse represents major societal problems, an unmet medical need resulting from our incomplete understanding of the mechanisms underlying alcohol’s actions in the brain. To uncover these mechanisms, animal models have been proposed. Here, we explore the effects of acute alcohol administration in zebrafish, a promising animal model in alcohol...

Behavioral neuroscience is an interdisciplinary field aimed at understanding the neurobiology of behavior. Numerous investigators turn to animals to model and understand the mechanisms underlying vertebrate brain function including human brain disorders, species that share evolutionary history with us. The zebrafish is a relatively new study specie...

The zebrafish has been employed in several fields of biology due to its translational relevance and its simplicity and ease of maintenance. As a result, zebrafish are kept in thousands of laboratories around the world. Current industry standards favour keeping the largest possible number of fish in the smallest possible volume of water to increase...

Animals are studied en masse by biologists around the world in a variety of biomedical and basic research studies. All this research benefits humankind and animals alike as it tackles a wide variety of problems ranging from those of conservation biology to medicine. Research with animal subjects is a complex endeavor that requires the cooperation a...

The dopaminergic neurotransmitter system is involved in numerous brain functions and behavioral processes. Alterations in this neurotransmitter system are associated with the pathogenesis of several human neurological disorders. Pharmacological agents that interact with the dopaminergic system allow the investigation of dopamine- mediated cellular...

Fetal Alcohol Spectrum Disorder (FASD) is characterized by a variety of morphological, behavioural and cognitive deficits, ranging from mild to severe. Numerous animal models, including the zebrafish, have been employed to better understand the onset, expression and progression of this disorder. Embryonic ethanol-induced deficits in learning and me...

Anxiety continues to represent a major unmet medical need. Despite the availability of numerous anxiolytic drugs, a large proportion of patients do not respond well to current pharmacotherapy, or their response diminishes with chronic drug application. To discover novel compounds and to investigate the mode of action of anxiolytic drugs, animal mod...

Video playback is a widely used technique for presentation of visual stimuli in animal behavior research. In the analysis of behavioral responses to social cues, presentation of video recordings of live conspecifics represents a consistently reproducible stimulus. However, video-recordings do not interact with the experimental subject, and thus thi...

The zebrafish is increasingly employed in behavioral neuroscience as a translationally relevant model organism for human central nervous system disorders. One of the most prevalent CNS disorders representing an unmet medical need is the disorder cluster defined under the umbrella term anxiety disorders. Zebrafish have been shown to respond to a var...

The number of zebrafish facilities steadily increases across the Globe. This chapter focusses on a fundamentally important aspect of zebrafish research: how to breed and raise zebrafish. It discusses practical aspects of these questions but also deals with conceptual issues, including whether in establishing zebrafish breeding and rearing methods w...

The zebrafish is increasingly well utilized in alcohol research, particularly in modeling human fetal alcohol spectrum disorders (FASD). FASD results from alcohol reaching the developing fetus intra utero, a completely preventable yet prevalent and devastating life-long disorder. The hope with animal models, including the zebrafish, is to discover...

Ethanol consumption is a worldwide problem. Sensitivity to acute effects of ethanol influences the development of chronic ethanol abuse and ethanol dependence. Environmental and genetic factors have been found to contribute to differential effects of acute ethanol. Animal models have been employed to investigate these factors. An increasingly frequ...

Olfaction is an important neural system for survival and fundamental behaviors such as predator avoidance, food finding, memory formation, reproduction, and social communication. However, the neural circuits and pathways associated with the olfactory system in various behaviors are not fully understood. Recent advances in optogenetics, high-resolut...

Over the past decade, the zebrafish has been increasingly employed in biomedical neuroscience research due to its numerous evolutionarily conserved features with mammals. Its simple brain and the several molecular tools available for this species make the zebrafish an appealing model to study mechanisms of complex brain functions, including learnin...

Understanding animal cognition has been of interest to scientists for well over a century (e.g., Melrose, 1921). Cognition is broadly defined as the neural and behavioral processes associated with the acquisition, retention, and use of information (Dukas, 2004). Since the discovery of multiple memory systems and of the fundamental role of the hippo...

Ethanol is one of the most commonly abused substances in the world, and ethanol abuse and dependence disorders represent major societal problems. However, appropriate treatment is lacking as we still do not fully understand the molecular bases of these disorders. The zebrafish is one of the model organisms utilized for studying such mechanisms. In...

The zebrafish has been utilized for the analysis of fundamental developmental processes for over four decades. More recently, this species is also employed in a variety of subdisciplines of biology, because it possesses evolutionarily conserved features and thus allows modeling of a variety of human disorders. One of these disorders is fetal alcoho...

Spatial learning and memory have been studied for several decades. Analyses of these processes pose fundamental scientific questions but are also relevant from a biomedical perspective. The cellular, synaptic and molecular mechanisms underlying spatial learning have been intensively investigated, yet the behavioral mechanisms/strategies in a spatia...

The dysfunction of dopaminergic signaling is associated with several neurological disorders. The use of pharmacological agents that interact with this signaling system may be employed to understand mechanisms underlying such disorders. Nutritional status can impact dopamine reuptake, receptor affinity, transporter activity, and the effects of drugs...

Alcoholism and alcohol abuse represent a significant medical and societal problem, and have been thoroughly investigated in humans as well as using animal models. A less well understood aspect of alcohol related disorders is the possible effect of this drug on offspring whose parents were exposed prior to conception. The zebrafish has been successf...

Social cognition and social behaviors are complex phenomena that involve numerous brain areas and underlying neurobiological mechanisms. Embryonic alcohol exposure may lead to the development of Fetal Alcohol Spectrum Disorder (FASD), a disorder that manifests with varying symptoms including abnormal social behavior and other cognitive deficits. An...

The zebrafish has become increasingly utilized in behavioral neuroscience, psychopharmacology, and behavior genetics research. However, little attention has been paid to the potential effects of environmental conditions fish are exposed to before and during behavioral testing. One such important factor is temperature, more specifically, the differe...

Social isolation is a well-established technique for inducing early adversity but, in rodent models, the need of parental care makes it difficult to distinguish the effects of social deprivation from the consequences of nutritional deficiencies. Zebrafish do not require parental care, allowing separation of social deprivation from nutritional depri...

The zebrafish is becoming increasingly well utilized in several fields of biology, including behavioral neuroscience. This review, based upon an Outstanding Achievement Award lecture presented by the author at an IBNS conference, explores the potential reasons for the popularity of this species. First, some theoretical questions are discussed, incl...

Despite much evidence of its economic and social costs, alcohol use continues to increase. Much remains to be known as to the effects of alcohol on neurodevelopment across the lifespan and in both sexes. We provide a comprehensive overview of the methodological approaches to ethanol administration when using animal models (primarily rodent models)...

Quantity discrimination, the ability to identify, process, and respond to differences in number, has been shown in a variety of animal species and may have fitness value. In fish, the ability to distinguish between numerically different shoals has been well studied. However, little work has been devoted to the investigation of such ability in a for...

Several studies have demonstrated translational potential of the zebrafish in modelling fetal alcohol spectrum disorders including the less severe forms of this disease. Short exposure to even low doses of alcohol during embryonic development has been shown to disrupt behavior, alter neurochemistry and expression of neuronal markers and glial cell...

Many animal species share the ability to discriminate between sets with different quantity of food items. In fish, this ability has rarely been investigated, although findings have been obtained do indicate a preference, as in other animals, for sets with large over small quantities. The role played by food item size has also been found to be impor...

The popularity of zebrafish is exponentially increasing. Unlike in the past, the zebrafish now is a subject of investigation by scientists of practically every subfield of biology, including psychopharmacology and behavior genetics. Simply put, the zebrafish is no longer considered a simple egg-producing tube for efficient delivery of thousands of...

Drug abuse and brain disorders related to drug comsumption are public health problems with harmful individual and social consequences. The identification of therapeutic targets and precise pharmacological treatments to these neuropsychiatric conditions associated with drug abuse are urgently needed. Understanding the link between neurobiological me...

Despite the known teratogenic effects of alcohol (ethanol) on the developing human fetus, the prevalence of fetal alcohol spectrum disorder (FASD) is not decreasing. Appropriate treatment for this life‐long disease has not been developed, and even diagnostic biomarkers are unavailable. FASD remains a large unmet medical need. Numerous animal models...

FASD results from the developing fetus being exposed to alcohol, and is characterized by morphological, behavioural and cognitive deficits. However, the expression, severity and age of onset of these symptoms has been found to show variation. This variation may partly be due to the developmental stage at which alcohol reached the developing fetus....

The zebrafish is becoming increasingly popular in behavior genetics as it appears to represent a reasonable compromise between system complexity and practical simplicity for biomedical research. For this reason, this species has been utilized in modeling and the mechanistic analysis of a variety of human disorders including abnormalities of the cen...

The zebrafish is becoming increasingly popular in behavioral neuroscience and behavior genetics as this species offers a potentially cheaper and simpler alternative to classical rodent laboratory species in the quest to model and understand the mechanisms of human CNS disorders. Anxiety-related human disorders still represent a large unmet medical...

In this chapter, we discuss numerous basic questions about the principles and applications of behavioral screening with zebrafish. It is a short chapter because this approach is rather novel with this species, and thus we do not yet have a rich history on this subject. Nevertheless, with the increasing sophistication of behavioral testing methods,...

Comparative studies on quantity discrimination in animals are important for understanding potential evolutionary roots of numerical competence. A previous study with angelfish has shown that they discriminate numerically different sets of same-sized food items and prefer the larger set. However, variables that covary with number were not controlled...

Fetal Alcohol Spectrum Disorders (FASD) represent a worldwide problem. The severity and types of symptoms of FASD vary, which may be due to the genotype of the fetus and the developmental stage at which the fetus is exposed to alcohol. The most prevalent forms of FASD present less severe symptoms, including behavioral and cognitive abnormalities, a...

The light dark paradigm is a common behavioral test used to screen a variety of pharmacological agents, including anxiogenics and anxiolytics. Although most often used in rodents, the light dark task has recently been adapted for use in zebrafish. However, a number of inconsistent findings have been reported for this species. Some have found zebraf...

The zebrafish has become an appropriate animal model in the analysis of numerous human brain disorders. A variety of neuropsychiatric conditions and neurodevelopmental disorders are comorbid with abnormal social behavior. Given the translational relevance of zebrafish, multidisciplinary studies employing behavioral, neurobiological, and molecular m...

The zebrafish is becoming increasingly utilized in behavioral neuroscience as it appears to strike a good compromise between practical simplicity and system complexity. Particularly in alcohol (ethanol) research, the zebrafish has been employed as a translationally relevant model organism. However, the majority of studies investigating the effects...

The light-dark preference task has been commonly used in rodents to screen for anxiogenic and anxiolytic drugs. However, recent adaptations of the light-dark preference test for zebrafish have produced inconsistent results. Several studies have reported that zebrafish exhibit a preference for light, while others have found a preference for black. W...

Alcohol (ethanol) abuse remains to be a leading cause of medical, including mental, problems throughout the world. Whether alcohol consumption leads to chronic use, and subsequent alcohol dependency and abuse is known to be influenced by the acute effects of this drug. Numerous factors may influence how alcohol administered acutely affects the indi...

Zebrafish show great potential for behavioral neuroscience. Promising lines of research, however, require the development and validation of software tools that will allow automated and cost-effective behavioral analysis. Building on our previous work with the RealFishTracker (in-house-developed tracking system), we present Argus, a data extraction...

The ability to distinguish between different quantities of items is fundamental in many ecological contexts, and it has been shown in different animal species. This ability may also be context specific. Quantity estimation in fish has mainly been analysed in the context of social behaviour, whereas a majority of studies conducted with species other...

Kudos description of the paper "The integration of sociality, monoamines and stress neuroendocrinology in fish models"

Animal‐focused research has been crucial for scientific advancement, but rodents are still taking a starring role. Starting as merely supporting evidence found in rodents, the use of fish models has slowly taken a more central role and expanded its overall contributions in areas such as social sciences, evolution, physiology and recently in transla...

Animal-focused research has been crucial for scientific advancement however, in this matter, rodents are still taking a starring role. Coming out from merely being supportive of evidence found in rodents, the use of fish models has slowly taken a more central role and expanded its overall contributions in areas such as social sciences, evolution, p...

The zebrafish has been successfully employed to model and study the effects of embryonic alcohol exposure. Short exposure to low alcohol concentrations during embryonic development has been shown to significantly disrupt social behavior as well as the dopaminergic and serotoninergic systems in zebrafish. However, analysis of potential effects of em...

Fetal Alcohol Spectrum Disorder (FASD) is one of the leading causes of mental health issues worldwide. Analysis of zebrafish exposed to alcohol during embryonic development confirmed that even low concentrations of alcohol for a short period of time may have lasting behavioral consequences at the adult or old age. The mechanism of this alteration h...

In recent years, Danio rerio (zebrafish) have increasingly been used as a laboratory organism to model and investigate CNS diseases and vertebrate behaviour. Several studies have analyzed learning and memory in adult zebrafish. However, juvenile zebrafish have only rarely been utilized for this purpose due to the paucity of learning paradigms. One...

Circadian rhythms impose temporal order throughout the brain and body, regulating physiological mechanisms and behaviours within a period of 24 hours. Genetic and neuroendocrine mechanisms under control of this system regulate rhythms of melatonin secretion, structural synaptic plasticity, locomotor activity and sleep. The zebrafish (Danio rerio) i...

The zebrafish has been successfully used to study learning and memory but systematic analyses of what constitute the best conditioned (CS) and unconditioned (US) stimuli have not been performed. We know little about how zebrafish may discriminate different stimuli. Currently, we are developing a discrimination learning paradigm whose aim is to inve...

Animal-focused research has been crucial for scientific advancement however, in this matter, rodents are still taking a starring role. Coming out from merely being supportive of evidence found in rodents, the use of fish models has slowly taken a more central role and expanded its overall contributions in areas such as social sciences, evolution, p...

Reproducibility and replicability are fundamentally important aspects of the scientific method. From time to time the discussion about whether scientific findings are replicable enough flares up. In fact, some recent publications claim we are witnessing a replication crisis. This is a particularly important problem in laboratory organisms that are...

The scientific community is increasingly concerned with the proportion of published "discoveries" that are not replicated in subsequent studies. The field of rodent behavioral phenotyping was one of the first to raise this concern, and to relate it to other methodological issues: the complex interaction between genotype and environment; the definit...

Significance Emotion-related responses, such as fear and anxiety, are important behavioral phenomena in most animal species, as well as in humans. However, the underlying mechanisms of fear and anxiety in animals and in humans are still largely unknown, and anxiety disorders continue to represent a large unmet medical need in the human clinic. Anim...

Numerous animal models have been successfully utilized to investigate neural mechanisms underlying the development of alcohol addiction. However, mammalian models are more expensive yet less amenable to high-throughput screens compared to zebrafish, whereas invertebrate models lack the complexity of vertebrates such as the zebrafish, and thus suffe...

Social isolation can be used to study behavioral, neural, and hormonal mechanisms that regulate interactions in social animals. Although isolation effects have been reported in social mammals and various fish species, systematic studies with isolated zebrafish are rare. Here, the authors examined behavior (social and nonsocial), physiological stres...

The zebrafish is a social vertebrate and an excellent translational model for a variety of human disorders. Abnormal social behavior is a hallmark of several human brain disorders. Social behavioral problems can arise as a result of adverse early social environment. Little is known about the effects of early social isolation in adult zebrafish. We...

Fetal Alcohol Spectrum Disorders (FASD) represent a large unmet medical need. Exposure of the developing human embryo to alcohol can lead to life-long suffering. Despite the well documented deleterious effects of alcohol on the developing fetus, pregnant women continue to drink alcohol, and FASD remains the leading cause of preventable mental retar...

The zebrafish is becoming a popular model organism for studying numerous biological phenomena. Among these are brain function and behavior, including social behavior. Although usually neglected, few studies have already demonstrated that even trivial factors, such as features of the holding water may alter zebrafish behavior. In this study, we empl...

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 inve...

The ability to discriminate between sets that differ in the number of elements can be useful in different contexts and may have survival and fitness consequences. As such, numerical/quantity discrimination has been demonstrated in a diversity of animal species. In the laboratory, this ability has been analyzed, for example, using binary choice test...

In recent years, a rapidly increasing number of scientific papers have been published that utilize zebrafish (Danio rerio) as an alternative model organism in the study of a wide range of biological phenomena from cancer to behavior. This is, in large part, due to the prolific nature, relative ease of maintenance, and sufficiently high genetic homo...

Fetal Alcohol Spectrum Disorders (FASD) is a syndrome characterized by neurological and behavioral impairments. A recently discovered hallmark of FASD is impaired social behavior. Avoidance of social interaction typical of FASD may be the result of increased anxiety. Previously, the zebrafish was successfully used to model embryonic alcohol induced...

The zebrafish represents an excellent compromise between system complexity and practical simplicity, features that make it useful for modeling and mechanistic analysis of complex brain disorders. Also promising are screens for psychoactive drugs with effects on larval and adult zebrafish behavior. This review, based upon a recent symposium held at...

Current behavioural tests for anxiety in zebrafish include the open-field, light-dark preference, and novel tank test. The purpose of the current study was to develop a high-throughput anxiety test for zebrafish. To achieve this, we designed a manual release bridge containing a weight that could be released from the right or left side of the tank,...

The objective of this study was to establish a new black/white anxiety test for larval zebrafish and to investigate the effects of diazepam. Previously, zebrafish larvae were shown to exhibit a preference for light areas over dark. Recently, we found adult zebrafish to show preference for black to white areas. We hypothesize that diazepam will indu...

The light-dark preference test has been extensively used to screen anxiolytic drugs and investigate mechanisms of anxiety with rodents. Recently, this task has been adapted to zebrafish, but a number of inconsistent findings have emerged. For example, some found zebrafish to avoid and others to prefer dark. Given the translational relevance of the...

This chapter focuses on the behavioral analysis of alcohol induced functional changes in the brain of zebrafish. It presents several recently developed behavioral paradigms, phenotypical testing methods one can utilize to detect and quantify the effect of alcohol on the vertebrate brain. Alcohol has been used and abused since the dawn of human civi...

Rapid technical advances in the field of computer animation (CA) and virtual reality (VR) have opened new avenues in animal behavior research. Animated stimuli are powerful tools as they offer standardization, repeatability and complete control over the stimulus presented, thereby 'reducing' and 'replacing' the animals used, and 'refining' the expe...

Analysis of the zebrafish allows one to combine two distinct scientific approaches, comparative ethology and neurobehavioral genetics. Furthermore, this species arguably represents an optimal compromise between system complexity and practical simplicity. This mini-review focuses on a complex form of learning, relational learning and memory, in zebr...

Zebrafish have become a popular animal model for studying the development of alcohol addiction. Several behavioral paradigms for studying alcohol addiction have been developed for zebrafish, including conditioned place preference, alcohol-induced tolerance, and withdrawal. However, alcohol choice preference tasks have not been established in zebraf...

The zebrafish enjoys several advantages over other model organisms. It is small, easy to maintain, prolific, and numerous genetic tools are available for it. For example, forward genetic screens have allowed investigators to identify important genes potentially involved in a variety of functions from embryogenesis to cancer. However, despite its so...

Alcohol addiction is a major unmet medical and economic issue for which very few efficacious pharmacological treatment options are currently available. The development and identification of new compounds and drugs to treat alcohol addiction is hampered by the high costs and low amenability of traditional laboratory rodents to high-throughput behavi...