pud's friend, I am a little confused by your question, but that could just be my issue

Are you talking about large segments in the spine or brain? When speaking of "holes" do you mean lesions or what is referred to as "black holes"?

As you know MS damages the myelin sheath and that is what cauaes the mis-communication with nerve signals as well as symptoms. Sclerosis means scaring (lesions). Lesions can heal all on their own. however, black holes are permanent axon damage.

Our brain has the ability to re-route around the damaged areas but only to a point. Lesions in the spine do not have that ability, there isn't enough room.

Here is a picture that may or may not be helpful.

http://www.med.umich.edu/1libr/aha/aha_mscleros_art.htm

Is any of this information what you were looking for? If not I'm sure we can figure this out...hopefully