By concentrating, I am able to produce a sensation throughout my body in my nervous system. Anywhere from my brain to my toes works.

 

Given that any sensation is the passage of an electromagnetic signal, what is the physiological effect of this on my nervous system? Could it be that I am capable of "massaging" my nervous system? Or am I contrubuting to wear of my nervous tissue? Perhaps there is no effect at all?

Producing a sensation is extremely vague, but you're not doing anything to your nervous system that you don't do just by thinking about anything else.

I have not heard of that particular effect being produced by meditation or self hypnosis, but it may be possible. I meditate to control pain, a technique taught by several eastern religions. Moreover, a few western physicians teach meditation and/or self hypnosis to control pain.