Transportation Cues and Play Behavior Influence Novelty-Induced Context Exploration

Context is the milieu in which everything occurs. Many research studies consider context, or even explicitly manipulate it, yet it remains challenging to characterize. We know that a context surrounds and influences tasks; however, the boundaries of its influence are difficult to define. In most instances, context is defined as surrounding and influencing the target task. While manipulations of the physical environment have been used to demonstrate the importance of context in memory, the effects of shifting physical environments are far from uniform. Memories may be more context-dependent when there are novel cues present. Experiences during transportation to the testing space have been shown to impact rodent behavior and memory; however, transportation’s relationship with novelty and physical environment is not fully understood. The current study explored how familiar vs novel cues, both within a physical environment and preceding it, impact exploration within a context. We manipulated novelty on 3 levels in this study: physical environment, object cue within that environment, and transportation cues preceding entrance to the testing environment. We measured exploration of the environment to use as an indirect measure of context familiarity; in a more familiar environment, rats should explore the environment less. We found that while rats showed differences in exploration in novel physical environments as well as following novel transportation, they explored equally when exposed to familiar vs novel objects. Despite the lack of behavioral differences based on object familiarity, when we removed the rats’ ability to manipulate the object -operationalized here as a form of play behavior- the effects of transportation cues dissipated. These data suggest that novelty can disrupt exploration behaviors when introduced in some contextual modalities, but not others, and that play behavior moderates this effect.