Leonie de Visser
Animal behavioural research is hampered by intrinsic limitations. Bringing animals from their familiar nesting area to a testing environment already is a major stressor which interferes with subsequent experiments, especially when psychosocial factors are involved. Ideally, researchers would conduct experiments in the very home cage environment the animals feel comfortable. PhD student Leonie de Visser has done just that. Her findings mark for example the first step for measuring anxiety in mice in a home cage environment.
De Visser successfully defended her PhD thesis on January 14th 2008 at Utrecht University. Under guidance of prof. Berry Spruijt from the faculty of Veterinary medicine, she developed a model for home cage testing for behavioural phenotyping of mice. She focused on anxiety, a much-studied emotion in mice, since disturbed anxiety may be involved in many human psychiatric diseases.
The central question is whether a stimulus can be found that differentiates between normal and over-anxious mice in a home cage environment. De Visser thinks she has found that stimulus in a bright light beam, focused on the feeding area. She tested this stimulus on two mice strains with different basal anxiety levels. The bright light creates a conflict for hungry yet light-avoiding mice. The behavioural balance between keeping away from the light and going into the feeding area for obtaining food is a good measure for anxiety, De Visser found. Mice going into the feeding area, not withstanding the light, are less anxious than mice that prefer to stay in the dark.
In subsequent experiments she administered mice with an anxiogenic or an anxiolytic compound and found indeed the light-avoiding behaviour to increase or decrease. De Visser points out that her anxiety test needs thorough additional pharmacological testing before it will be accepted as an alternative to traditional open field experiments.
“I feel home cage experiments are a promising approach to behavioural research”, De Visser states. “Colleagues generally appreciate the concept, but are concerned with backward compatibility. Indeed, with all present know-how built on a number of commonly agreed-on tests, embracing the home cage paradigm would come down to changing a major fundament of behavioural research. That will take time, maybe even decades.”