reticular formation 
(also reticular activating system)
noun Anatomy
A diffuse network of nerve pathways in the brainstem connecting the spinal cord, cerebrum, and cerebellum, and mediating the overall level of consciousness.Suggestions for regions of the brain that could be the site of action have included the brain stem reticular formation, the cerebral cortex, and the thalamus....
- For example, it is possible that the brainstem reticular formation is divided into the same number of nuclei in all jawed vertebrates.
- In the central nervous system, the reticular activating system is a major pathway for communication between the brain and the rest of the body.