1) Tropism 
An ability to invade and live in neural tissue. This term is usually used to describe the ability of viruses to infect nerve tissue.
(ndbobr-rot´ro-piz″әm) the quality of having a special affinity for nerve tissue. the alleged tendency of regenerating nerve fibers to grow toward specific portions of the periphery. adj., neurotrop´ic., adj.
[n] - an affinity for neural tissues
noun an affinity for neural tissues
the quality of being neurotropic.