Behavioural research: New findings on the stress reactions of the Princess of Burundi

Aquarium enthusiasts are familiar with the East African cichlid Neolamprologus pulcher as the Princess of Burundi. Scientifically, it is often used in animal models to study behaviour - the University of Veterinary Medicine Vienna is one of the world's leading institutions in this field. A research group led by the Konrad Lorenz Institute of Ethology (KLIVV) has now investigated how the blockade of glucocorticoid receptors affects stress and behaviour. The results of the study have been published in the scientific journal “Physiology & Behavior”.

The researchers investigated the question of whether the so-called stress axis is associated with behavioural flexibility in the social cichlid Neolamprologus pulcher. To this end, the scientists pharmacologically blocked the glucocorticoid receptors (GR) of adult N. pulcher by administering a GR antagonist in a minimally invasive manner. First author Stefan Fischer from the Konrad Lorenz Institute of Ethology (KLIVV) at the Vetmeduni explains the background to the study: “Glucocorticoid receptors (GR) are important mediators of the stress response. GR blockade prevents recovery after a stressful event, which we hypothesized would impair behavioural flexibility.” After administration of the GR antagonist, the fish were repeatedly exposed to a predator and their behavioural flexibility was tested using a detour task. The fish had to find a new, longer route to a shelter when the shortest route was blocked.

GR blockage altered fear perception and reduced behavioural flexibility

While the time to find a shelter did not differ between the fish given a GR antagonist and a control group without GR antagonists, the fish with GR blockade showed more failed attempts at the detour tasks than the control fish. In addition, the poor performance in the detour tasks was associated with an increase in fear-related behaviours. “This suggests that blocking GR alters the perception of fear and leads to reduced behavioural flexibility. Our results therefore demonstrate a possible link between the ability to recover from stressors and behavioural flexibility in N. pulcher, potentially impacting effective and adaptive coping with changes in the environment,” said co-author Leonida Fusani from KLIVV.

An exciting combination: How stress responses affect behavioral flexibility

Behavioural flexibility plays an important role in the way animals cope with novel situations, and physiological stress responses are adaptive and highly efficient mechanisms for coping with unpredictable events. “To better understand how stress affects behavioural flexibility in a natural context, we therefore performed direct manipulations of the stress response and conducted cognitive tests in ecologically relevant contexts, whereas previous studies were mostly conducted only under laboratory conditions,” emphasizes Stefan Fischer.