SYMPOSIUM

Defining and Measuring Dominant-Submissive Behavior

Ewa Malatynska

Neuroscientists make every effort to automate behavioral tests to minimize subjective judgment and manual labor, and to maximize repeatability of the results between laboratories while increasing the throughput of experimental endpoints. In recent years, these efforts have accelerated due to the development of many inbred or transgenic mice strains that needed systematic behavioral phenotyping in order to find the functions delineated to strain differences or specific genes. At the same time, the development of in vitro biochemical high-throughput drug screening tests highlighted similar needs in behavioral neurosciences where the intact organism is a subject of study.

This symposium will focus on dominant-subordinate behavior across species. Social hierarchy is common in many animal phyla including fish, reptiles, birds and mammals. This extends to different species of a phylum. For example, within mammals this behavior is found among mice, rats, dogs, and most primates as well as humans. The premise of this symposium is that dominance and subordination observed in humans can be related to mania and depression and that important elements of both mania and depression can be modeled in animals based on observation of dominant and submissive behavior exhibited under well-defined conditions.

Human dominant-subordinate social behavior can be viewed as abnormal (e.g., active non-participant 'manic' and passive non-participant 'sad') or normal social behavior (active participant 'warm' and passive participant 'shy'). The interaction of subjects under these four conditions and their subsequent behavior on a dyadic game will be described in terms of the behavioral mechanisms of social adaptation. Investigators have used various endpoints to measure dominance in animals. This includes observation of hierarchy in groups of animals (two or more) by denoting their communication through different body postures, competition for priority of access to different resources using distinct types of scoring, and social defeat based on animal territorial instinct. These distinct approaches to measure dominance and submissiveness will be discussed by different speakers during the symposium, with the focus on the criteria used to define dominance and submissiveness and efforts to automate measurements.

Just as affective disorders are mood illnesses with two opposite poles, melancholia (depression) and mania that are expressed to different degrees in affected individuals, dominance and submissiveness are also two contrasting behavioral poles distributed as a continuum along an axis with less or more dominant or submissive animals. The importance of the selection process for these behavioral extremes will be underlined as a necessary factor for successful modeling of mania by dominance and depression by submissiveness.

Speakers: