Central Nervous System Viral Diseases: Viral infections of the brain, spinal cord, meninges, or perimeningeal spaces.Central Nervous System: The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges.Central Nervous System Diseases: Diseases of any component of the brain (including the cerebral hemispheres, diencephalon, brain stem, and cerebellum) or the spinal cord.Virus Diseases: A general term for diseases produced by viruses.Central Nervous System Neoplasms: Benign and malignant neoplastic processes that arise from or secondarily involve the brain, spinal cord, or meninges.Nervous System: The entire nerve apparatus, composed of a central part, the brain and spinal cord, and a peripheral part, the cranial and spinal nerves, autonomic ganglia, and plexuses. (Stedman, 26th ed)Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Central Nervous System Infections: Pathogenic infections of the brain, spinal cord, and meninges. DNA VIRUS INFECTIONS; RNA VIRUS INFECTIONS; BACTERIAL INFECTIONS; MYCOPLASMA INFECTIONS; SPIROCHAETALES INFECTIONS; fungal infections; PROTOZOAN INFECTIONS; HELMINTHIASIS; and PRION DISEASES may involve the central nervous system as a primary or secondary process.