The integration of sociality, monoamines and stress neuroendocrinology in fish models: applications in the neurosciences

Abstract

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 translational medical research. In the neurosciences, zebrafish Danio rerio have been widely adopted, contributing to our understanding of the genetic control of brain processes and the effects of pharmacological manipulations. However, discussion continues regarding the paradox of function versus structure, when fishes and mammals are compared and on the potentially evolutionarily conserved nature of behaviour across fish species. From a behavioural standpoint, we explore aversive-stress and social behaviour in selected fish models and refer to the extensive contributions of stress and monoaminergic systems. We suggest that, in spite of marked neuroanatomical differences between fishes and mammals, stress and sociality are conserved at the behavioural and molecular levels. We also suggest that stress and sociality are mediated by monoamines in predictable and non-trivial ways and that monoamines could bridge the relationship between stress and social behaviour. To reconcile the level of divergence with the level of similarity, we need neuroanatomical, pharmacological, behavioural and ecological studies conducted in the laboratory and in nature. These areas need to add to each other to enhance our understanding of fish behaviour and ultimately how this all may lead to better model systems for translational studies.

Social Plasticity in the Fish Brain: Neuroscientific and Ethological Aspects

“…A similar approach to other fields of neuroscience can benefit the field by comparing taxa to infer how variations in one domain (e.g., gene expression, connectivity, activation patterns) relates to variation in behavior. Of relevance to the question of social plasticity, fish species can be used to understand how variations in social environment impact variations in behavior and brain structure and function (Soares et al, 2018a).…”

“…In addition to increasing possibilities to understand social plasticity, fish models can also increase translational relevance for research in social behavior (Oliveira, 2009;Soares et al, 2018a). This is relevant, because human sociality is crucial for mental health, and social stressors represent a very important source of suffering that can lead to mental disorders (Soares et al, 2018b).…”

“…Nodes of the SDMN are identified in teleost fish, although for many of them only partial homologies have been established and many remain undefined, debated, or controversial (cf. Soares et al 2018a for a review; Goodson and Kingsbury, 2013) ( Table 1). This is primarily due to the differences in forebrain development between teleosts (eversion) and tetrapods (evagination).…”

“…In the wild, the model organism zebrafish (Danio rerio) live in small groups that form shoals, which usually include small heterospecifics (Suriyampola et al, 2015). Shoaling behavior has been exploited as a tool to study the neurobiology of social behavior in zebrafish (Soares et al, 2018a). Within the shoal, dominant-subordinate relationships are established, a model of social plasticity that has also been exploited successfully (cf.…”

‘The Bold are the Sociable’: Personality, sociability and lateralized utilization of brain hemisphere in the juveniles of a megafish Deccan Mahseer (Tor khudree)

“…Although individual variation and its consistency are being studied at behavioural and physiological (e.g. metabolic rate) levels (Boulton et al, 2015; Rupia et al, 2016; Mathot and Frankenhuis, 2018), search for its neural correlates has received greater attention in the last two decades (Coppens et al, 2010; Silva et al, 2014; Soares et al, 2018). According to Goursot et al (2018), studying the relationship between personality traits and the lateralized utilization of brain hemisphere could provide insights into the neurobiological mechanisms underlying individual variation in behaviour.…”