Inter-individual and inter-strain differences in cognitive and social abilities of Dark Agouti and Wistar Han rats

Abstract

Background: Healthy animals showing extreme behaviours spontaneously that resemble human psychiatric symptoms are relevant models to study the natural psychobiological processes of maladapted behaviours. Healthy poor decision makers (PDMs) identified using a Rat Gambling Task, co-express a combination of cognitive and reward-based characteristics similar to symptoms observed in human patients with impulse-control disorders. The main goals of this study were to 1) confirm the existence of PDMs and their unique behavioural phenotypes in the Dark Agouti (DA) and Wistar Han (WH), 2) to extend the behavioural profile of the PDMs to probability-based decision-making and social behaviours and 3) to discuss how the key traits of each strain could be relevant for biomedical research. Methods: We compared cognitive abilities, natural behaviours and physiological responses in DA and WH rats using several tests. We analysed the results at the strain and the individual level. Results: Previous findings in WH rats were reproduced and could be generalized to DA. Each PDM of either strain displayed a similar, naturally occurring, combination of behavioural traits, including possibly higher social rank, but no deficits in probability-based decisionmaking. A Random forest analysis revealed interesting discriminating traits between WH and DA. Conclusion: The reproducibility and conservation of the socio-cognitive and behavioural phenotypes of GDM (good decision maker) and PDM individuals in the two genetically different strains of WH and DA support a good translational validity of these phenotypes. Both DA and WH rat strains present large phenotypic variations in behaviour pertinent for the study of the underlying mechanisms of poor decision making and associated disorders.

Functional connectivity in reward‐related networks is associated with individual differences in gambling strategies in male Lister hooded rats

“…Human data reveal that patients with GD expressed a more risk‐taking behaviour, 19,20 though diverging results regarding risk‐taking behaviour have been found in rodents. Some studies have revealed that risk‐taking differs between good decision makers and poor decision makers, 22–24 whereas others have not found this relationship 21 . Such discrepancies in results could be due to the use of different rGT versions or methods used to measure risk‐taking behaviour.…”

“…Human data reveal that patients with GD express a more risktaking behaviour, 19,20 although diverging results regarding the relationship between decision-making in the rGT and risk-taking behaviour have been found in rats. [21][22][23][24] This discrepancy may be due to the limitation of many conventional tests in capturing risk-taking behaviour. Moreover, in rats, little is known about behavioural traits associated with individual differences in gambling strategies.…”

Constitutive depletion of brain serotonin differentially affects rats’ social and cognitive abilities

“…Due to space limitations, details of apparatus, methods, and parameters of this study are provided in the supplemental methods section. Unless stated otherwise, rats were trained and tested following established procedures described previously (52). The order of tests is shown in Fig.…”

Constitutive depletion of brain serotonin differentially affects rats’ social and cognitive abilities

“…Despite the appeal to reduce mental disorders to impairments studied in isolation, the reality is that the complexity of human mental disorders cannot be explained only in terms of their components, as their interaction plays a critical role in the emergence of the pathology. 49 , 50 , 51 , 52 Using a multidimensional profiling approach, 53 we studied the effect of brain serotonin depletion on the expression of several cognitive, social, and affective functions in the same individual. The aim of the study was to identify which of these functions were most affected by the absence of central serotonin and discuss how those key symptoms compare to mental conditions observed in humans.…”