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Your ideas about the seemingly plastic nature of the circuits responsible for producing Tourette episodes remind me of some questions that I posted in last week's forum.  Here is a portion of that post:

"...in class, we touched on the possibility that neuron connections are capable of changing, and that such a change would cause a change in behavior.  Are "random firing" types of disorders caused by changes in neuron connections?  Why is it that some pathways seem to be more prone to change than others?"

It seems to me that the ability of many Tourette patients to better control their episodes as they get older could be an example of new neuron pathways being developed.  I too am having trouble thinking of a way in which an axon that allows sodium ions to leak across its membrane could fix itself.  However, it is possible for the nervous system to counteract these "faulty signals" caused by the random leaking/passive flow of positive charge.  For example, a second signal could be sent via a functioning pathway to cancel out the effects of the first.  This way, the structure of the leaky axons themselves would not need to change.

How might the I-function play a role in all of this?  From what I have experienced, I think that the I-function is one of the areas of the nervous that are most plastic (ex: thought pathways are constantly modified, whereas pathways controlling physical reflexes do not seem to change at all). If, as you suggest, the I-function is aware of the output generated by "faulty signals" in people with Tourette Syndrome (the behavioral tics), then perhaps the I-function is responsible for generating the "opposing" signals to prevent this output.  It seems to me that many symptoms of Tourette Syndrome are behaviors that only the I-function would "want" to stop.  (For example, there is no physical reflex that stops a person from making socially unacceptable comments).  Pathways to stop these behaviors would take some time to develop, which could explain why children have less control over their episodes.  Furthermore, a person is constantly developing thoughts as to which behaviors are socially acceptable and which are not as he/she grows older, and these new thoughts could contribute to an older individual's greater control over the effects of the disorder.

Just some thoughts :)