Environmental enrichment and the striatum: the influence of environment on inhibitory circuitry within the striatum of environmentally enriched animals and behavioural consequences

Abstract

The nervous system is integral to the healthy and whole functioning of an organism, mediating interactions with and responses to an organism’s surroundings. Environmental enrichment (EE) provides stimuli above that usually experienced within the laboratory environment, and has been shown to greatly impact the nervous system. The maturation of inhibitory circuitry controls the level of neuroplasticity and functional maturity present within neural systems. This thesis investigates the effect of EE upon the development of inhibitory circuitry within the striatum. The striatum is the entry nucleus to the basal ganglia, and as such mediates various cognitive and sensorimotor behaviours. This thesis investigates the effect of EE upon striatally-mediated behaviours of both juvenile and adult animals. This thesis demonstrates that exposure to an enriched environment accelerates maturation of inhibitory circuitry within the striatum and increases the number of active inhibitory interneurons within the adult striatum; improves problem solving and goal-orientated learning; and influences animal behaviours within automated testing apparatus. This work sheds light on the mechanisms by which EE impacts an important nucleus within the brain, and has implications for potential treatments of neurological disorders. Determining the optimum environment for healthy brain development may also aid in early education and intervention programs targeted at young children.