A Robotics-Based Behavioral Paradigm to Measure Anxiety-Related Responses in Zebrafish

Abstract

Zebrafish are gaining momentum as a laboratory animal species for the study of anxiety-related disorders in translational research, whereby they serve a fundamental complement to laboratory rodents. Several anxiety-related behavioral paradigms, which rest upon the presentation of live predatorial stimuli, may yield inconsistent results due to fatigue, habituation, or idiosyncratic responses exhibited by the stimulus itself. To overcome these limitations, we designed and manufactured a fully controllable robot inspired by a natural aquatic predator (Indian leaf fish, Nandus nandus) of zebrafish. We report that this robot elicits aversive antipredatorial reactions in a preference test and that data obtained therein correlate with data observed in traditional anxiety- and fear-related tests (light/dark preference and shelter-seeking). Finally, ethanol administration (0.25; 0.50; 1.00%) exerts anxiolytic effects, thus supporting the view that robotic stimuli can be used in the analysis of anxiety-related behaviors in zebrafish.

Information Flow in Animal-Robot Interactions

“…This is direct evidence in support of the efficacy of a robotics-based solution in animal behavior studies. For example, often cited benefits of using robotics in experimental paradigms addressing functional and dysfunctional processes are the reliability and repeatability of the animal response to the robot [47,48]. In this respect, the marked one-directional influence of the replica on the focal fish indicates that consistent responses may be elicited more easily with a robot than a live stimulus.…”

“…Experiments were filmed at 15 frames per second at a resolution of 800 × 600 pixels. A similar setup was used for other zebrafish-robot interactions experiments by our group [46][47][48][49][50][51]. Fish replicas, 3 cm in length, were fabricated using Acrylonitrile Butadiene Styrene (ABS) thermoplastic in a 3D prototyping machine (Dimension Elite, Stratasys Ltd., Eden Prairie, MN, USA).…”

A jump persistent turning walker to model zebrafish locomotion

“…Freezing was quantified on the basis of [57], where the fish was considered freezing if it remained within a circle of 2 cm radius for more than 2 seconds. A threshold of 10% of time freezing was used to dismiss trials for abnormal stress levels [11,21]. To avoid numerical confounds associated with the interaction with the wall, fish spending more than 35% of the experimental time within two body lengths of the circular partition were also dismissed.…”

“…Furthermore, with the aim of generating highthroughput behavioural data [5][6][7], considerable research is being performed to integrate computer-animated images and robotic replicas of conspecifics, heterospecifics and predators [8][9][10][11][12]. Zebrafish have been used to study the fundamental mechanisms governing the exhibition of emotional patterns [13,14], individual response to alcohol and drugs of abuse [15][16][17], and higher order brain functions, such as memory and learning [18].…”

Closed-loop interactions between a shoal of zebrafish and a group of robotic fish in a circular corridor

“…In the past decade, researchers in the field of animal-robot interaction have tried to extend this field of study to fish. Four major types of robotic devices have been created for fish-robot interaction studies: a two-dimensional moving platform underneath a tank to transmit the two-dimensional motions to a lure inside the tank using magnetic coupling, as shown in Faria et al (2010); robotic arms that steer lures inside aquariums, as shown in Phamduy et al (2014), Polverino and Porfiri (2013a, b), Kopman et al (2013), Abaid et al (2012), Butail et al (2014a), Cianca et al (2013), Ladu et al (2015a, b), Polverino et al (2012), Spinello et al (2013), Bartolini et al (2016), Donati et al (2016), Ruberto et al (2016Ruberto et al ( , 2017, and Romano et al (2017); wheeled mobile robots that move below a tank and steer lures inside the tank using magnetic coupling, as shown in Swain et al (2012), Rashid et al (2012), and Landgraf et al (2013Landgraf et al ( , 2016; robotic lures that swim autonomously underwater, as shown in Abaid et al (2013), Butail et al (2013), and Butail et al (2014b). While these studies have demonstrated the potential to develop artificial devices able to interact with fish, there is no solution involving multiple robots that move independently and reproduce the same trajectory and locomotion patterns as the fish being studied, which would show how a group of robotic agents would integrate and be able to modulate the collective decision-making process of the animals, as was the case in the LEURRE project.…”