Abstract
Once considered a uniquely human attribute, behavioral laterality has proven to be ubiquitous among non□human animals, being frequently associated with different neurophenotypes in rodents and fish species. Zebrafish (Danio rerio) are a versatile and complementary vertebrate model system that has been widely used in translational neuropsychiatric research due their highly conserved genetic homology, well characterized physiological and extensive behavioral repertoire. Although the spontaneous left- and right-bias responses and associated behavioral domains (e.g. stress reactivity, aggression and learning) have previously been observed in other teleost species, no information regarding the natural left-right bias responses of zebrafish has been described. Thus, we aimed to investigate the existence and incidence of natural left-right bias of adult zebrafish in the Y-maze test and explore any relationship of biasedness on the performance of different behavioral domains. This included learning about threat-cues in the fear conditioning test and locomotion and anxiety-related behavior in the novel tank diving test. In conclusion, we showed for the first time that zebrafish exhibit a natural manifestation of behavioral lateralization which can influence aversive learning responses. Although laterality did not change locomotion or anxiety-related behaviors, we found that biased animals showed a reduction of short-term memory performance in the Y-maze and increase learning associated to fear cues.
