Construction and use of mental models: Organizing principles for the science of brain and mind.

As an organizing framework for questions of mind and brain, I discuss how the brain builds and uses mental models. Mental models provide a complex, structured description of some situation in the world. The role of perception is to build such a model for the current environment; knowledge provides many of the building blocks; in episodic memory, a previous model is reinstated; in cognitive control, the model dictates a choice of action. A model, I suggest, is a compositional, whole brain state, combining information from multiple specialised brain systems into a structured description of entities in the model and their roles and relationships. The default mode network may play an organizational role as parts of a model are combined into a broader whole. The model combines an active attentional foreground with a more extensive, latent background. Foreground is based on active neural firing, orchestrated by the brain's multiple demand network. Background may also include low-intensity neural activity, but with a substantial contribution from both faster and slower aspects of synaptic change. Interplay between foreground and background underlies core aspects of cognition, including cognitive control, problem solving, abstraction, and learning. Together, these proposals suggest how integrated, whole-brain functions build mental models, providing a unifying framework for the diverse concerns of cognitive neuroscience.