Something else that isn't necessarily common knowledge is that after a certain age (I think it's 40??), a few brain lesions are actually considered 'normal'!!
I know, I thought it was odd as well, but this is what I have read on several fairly reliable sites.
My Brain MRI showed several small lesions and my GP told me that wasn't so abnormal - but he learned all that he knows of Lyme through me from either articles that I brought to him, or from tidbits that he read trying to just keep me from having to be admitted to the hospital (no- not the mental one!! Giggle!).