The term behavioral state system refers to one of three subdivisions of the cerebrospinal trunk. As a part of the central nervous system subdivided on the basis of function and connectivity, it consists of fourteen nuclei. Among the best known are the suprachiasmatic nucleus, the substantia nigra, the pedunculopontine nucleus, the rostral pontine reticular nucleus, the raphe nuclei and the locus ceruleus. For a complete listing click below: Models Where It Appears. Among other functions the behavioral state system is responsible for the intrinsic control of sleep and wakefulness ( Swanson-2003 ). The other subdivisions of the cerebrospinal trunk are the subcortical sensory systems and the subcortical motor system.