I don't know if it improves CNS functioning beyond "baseline," but vitamin B-6 does support the nervous system.
Jesse Ventura's daughter suffered from a form of epilepsy that manifested in seizures.
Doctors determined it resulted from her body's inability to metabolize B-6.
So, they put her on mega-doses of the stuff, and her seizures stopped.
The dr's attributed the results to B-6's effects on the child's CNS.