Consciousness is a puzzling property of complex biological systems that depends on their state. The central question is how immaterial conscious mental states relate to physical brain states. Scientists are using various empirical approaches to investigate the neural basis of consciousness. This article reviews those approaches and summarizes what has been learned so far.
A model of consciousness is a theoretical description that links brain properties—such as fast irregular electrical activity and widespread brain activation—to phenomenal properties like qualia, a first-person perspective, and the unity of a conscious scene. Because these properties are diverse, useful models can be either mathematical/logical or verbal/conceptual.