Adaptação de modelo de impulsividade para o zebrafish (Danio rerio)

Abstract

Zebrafish (Danio rerio) is becoming a very popular model for the study of behavioral phenomena. The development of impulsivity models using this species is only beginning, with only one model – based on the 5CSRTT – already adapted. Widespread models such as delay-discounting were not adapted yet. The objective of this work is the adaptation of a rodent impulsivity model using zebrafish as subjects. The work is organized into three articles. In the first one, we performed a review of impulsive-live behavioral models. Although the results show more than 27 different models, more than half of the reviewed papers used either one of two models: delay-discounting and 5CSRTT, which are models of impulsive choice and impulsive action, respectively. Because there is already a model based on the 5CSRTT adapted for the zebrafish, we decided to adapt a delay-discounting model for the species. In the second article, we investigated zebrafish responding under a peak procedure. The subjects did not acquire the typical response pattern in that task but showed time discrimination under a fixed-interval schedule. We argue that our results are due to the aging process of the subjects, given the long duration of training. In the third article, we investigated the discrimination of food quantities by zebrafish. The subjects did not discriminate between two different quantities in any of the ratios tested (1 vs. 2, 1 vs. 3, 1 vs. 4 e 2 vs. 3 items). Although such subjects may be unable to discriminate between different quantities of food, it has been shown that they are able to discriminate between different quantities of conspecifics in shoals. We conclude that, despite our negative results, the development of a delay-discounting based model using different shoal sizes as reinforcement could be possible. Future research should concentrate on different procedures than those adopted here.