Plasticity in Ant Mushroom Bodies and its Relationship to Sensory Processing and Behavior

University Of Arizona, Tucson AZ

Investigators

Abstract

The complex social lifestyles of ants are based on their ability to perform different tasks during an individual's lifetime (e.g. brood-care, guarding, foraging) and on learning and memory. These behaviors are controlled by the brain and depend on brain plasticity. The aim of the project is to study the causal relationship between the structure and function of the brain and the complex behavior that it controls. Particular brain regions and individual nerve cells that generate complex behavior will be analyzed in different ant species using diverse anatomical techniques. Morphological differences will be correlated with the behavioral performance of the respective species or guild member (e.g. forager versus nurse ant). The behavior and learning ability of each ant will be quantified in standardized tests (e.g. maze performance), the effect of brain lesions on the ant's behavior will be assessed, and the electrical activity of prominent nerve cells in the ant brain will be correlated with behavioral changes. Together, these techniques will help to understand how a small brain with a limited number of nerve cells can yet generate the behavioral plasticity required for the survival of the colony. Ants have to cope with the same general problems and physical constraints as larger animals and humans. Their brains function by the same principles and their nerve cells rely on the same cellular mechanisms and network properties. Unlike vertebrates including humans, where populations of thousands or millions of nerve cells control each small behavioral component, in ants much fewer cells orchestrate the behavior. Hence the effect of a single nerve cell's activity on behavioral changes is much stronger and can be studied much more directly in ants than in larger animals. This and their complex behavior and high learning capacities makes the ants particularly well suited as model systems for research on brain plasticity. Studying the changes that occur in the brains of ants that learn a simple task may help us to better understand how our own brains acquire new capabilities and optimize our behavioral output.