A developmental process, independent of morphogenetic (shape) change, that is required for the central nervous system to attain its fully functional state. The central nervous system is the core nervous system that serves an integrating and coordinating function. In vertebrates it consists of the brain and spinal cord. In those invertebrates with a central nervous system it typically consists of a brain, cerebral ganglia and a nerve cord. [ GOC:dph http://openisbn.com/search.php?q=0582227089&isbn=1/ GOC:cls http://purl.obolibrary.org/obo/go/references/0000021 GOC:jid GOC:dgh ]