Emotional behavior in aquatic organisms? Lessons from crayfish and zebrafish

Abstract

Experimental animal models are a valuable tool to study the neurobiology of emotional behavior and mechanisms underlying human affective disorders. Mounting evidence suggests that various aquatic organisms, including both vertebrate (e.g., zebrafish) and invertebrate (e.g., crayfish) species, may be relevant to study animal emotional response and its deficits. Ideally, model organisms of disease should possess considerable genetic and physiological homology to mammals, display robust behavioral and physiological responses to stress, and should be sensitive to a wide range of drugs known to modulate stress and affective behaviors. Here, we summarize recent findings in the field of zebrafish‐ and crayfish‐based tests of stress, anxiety, aggressiveness and social preference, and discuss further perspectives of using these novel model organisms in translational biological psychiatry. Outlining the remaining questions in this field, we also emphasize the need in further development and a wider use of crayfish and zebrafish models to study the pathogenesis of affective disorders.

Social Preference Tests in Zebrafish: A Systematic Review

“…Even though there are significant differences between shoaling and schooling, these two terms are often used interchangeably in research studies. Study of the zebrafish behavioral repertoire includes behaviors related to single individuals, such as modalities of swimming (30) and of prey capture (31), emotional responses to stimuli (32), and cognitive abilities (33), as well as group-level behaviors, such as shoaling, schooling (34) and courtship (35).…”

A comparative analysis of Danionella cerebrum and zebrafish (Danio rerio) larval locomotor activity in a light-dark test

“…Thigmotaxis or centrophobism, i.e., the tendency of animals to avoid the center area of an open field or arena and instead to spend more time in its periphery, is a behavioral response that is evolutionary conserved from Drosophila ( Besson and Martin, 2005 ; Mohammad et al, 2016 ) to zebrafish ( Colwill and Creton, 2011 ; Richendrfer et al, 2012 ; Schnörr et al, 2012 ; Pietri et al, 2013 ; Zhang et al, 2017 ; Xu and Guo, 2020 ) and mammals ( Hall, 1934 ; Denenberg, 1969 ; Treit and Fundytus, 1988 ; Prut and Belzung, 2003 ), including humans ( Walz et al, 2016 ; Gromer et al, 2021 ). Although a natural behavioral tendency across species, it has been suggested that thigmotaxis is indicative of an anxiety-like state in both larval and adult zebrafish ( Maximino et al, 2010 ; Richendrfer et al, 2012 ; Schnörr et al, 2012 ; Pietri et al, 2013 ; Zhang et al, 2017 ; Abreu et al, 2020 ; Xu and Guo, 2020 ).…”

“…That Dc larvae show an increased thigmotaxis relative to zebrafish during the light ( Figure 2F ), together with a strong startle response during a dark to light switch ( Figures 2C,D and Supplementary Figures 1C,D ), and the observation that Dc preferentially occupy the lower zone of a water column ( Rajan et al, 2022b , see also below) appears to be indicating that Dc may generally favor a rather dark over a light environment. Since thigmotaxis has also been associated with an anxiety-like behavior ( Maximino et al, 2010 ; Richendrfer et al, 2012 ; Schnörr et al, 2012 ; Pietri et al, 2013 ; Zhang et al, 2017 ; Abreu et al, 2020 ; Xu and Guo, 2020 ), increased thigmotaxis of Dc relative to zebrafish during the light periods could also be indicating increased levels of anxiety in Dc . Although we cannot exclude this possibility, ascribing heightened levels of anxiety to Dc compared to zebrafish based solely on a single behavioral parameter appears to be premature, which is why we currently favor a natural habitat or environmental-based hypothesis as a more plausible explanation for the observed phenomena.…”

“…10.3389/fnbeh.2022.885775 anxiety-like state in both larval and adult zebrafish (Maximino et al, 2010;Richendrfer et al, 2012;Schnörr et al, 2012;Pietri et al, 2013;Zhang et al, 2017;Abreu et al, 2020;Xu and Guo, 2020).…”

Understanding CNS Effects of Antimicrobial Drugs Using Zebrafish Models

“…Alongside rodent models, a small freshwater teleost fish, the zebrafish ( Danio rerio ), has become a powerful in vivo vertebrate system widely used in biomedicine [ 2 ]. Characterized by high genetic (~70%) and physiological homology to humans [ 3 ], zebrafish are also increasingly utilized in the central nervous system (CNS) research, including modeling neurodegeneration (e.g., Alzheimer’s, Parkinson’s, and Huntington’s diseases, amyotrophic lateral sclerosis) [ 4 ], epilepsy [ 5 ], affective disorders [ 6 ], addiction and various other drug-induced conditions [ 7 ]. In addition to offering multiple genetic models of CNS pathogenesis [ 8 ], zebrafish can also serve as sensitive pharmacological screens for major classes of neuroactive drugs [ 9 ], including antidepressants, anxiolytics, antipsychotics, antiepileptics, and anesthetics [ 10 , 11 ].…”