Habituation and Behavioural Response of Confinement-Induced Anxiety Conditions in a Zebrafish Model

Abstract

The zebrafish model is an emerging model for the study of the complex behavioural patterns noted in depression and neurological disorders. Confinement and memory loss are linked with cognition and mental health impairment, where confinement paradigms are assessed using other behavioural responses based on novel tanks or T tanks. Since zebrafish are exploratory animals, the impact during confinement cannot be evaluated using a novel tank or T tank. The present study investigates the response of the zebrafish to acute confinement and assesses its memory-based learning behaviour through parameters such as movement, swimming speed, and time spent inside the confined space. The movement and swimming speed of the fishes in confinement showed no significant difference. When confined inside a space, the fish showed their anxiety with erratic movements or bouts of freezing, which declined by 83%, during the six days of confinement and the escape time from the confinement space also decreased by 58%. The impact of anxiety, resulting in clockwise and counter-clockwise movement, also reduced after three days. Our results summarise that the decrease in anxiety can help the fish in habituating itself to a forced condition. This experiment on zebrafish behavioural biology is used to assess the cognitive behaviour against confinement, and it emphasizes the learning of behavioural adaptions under both crowded and solitary conditions.