I'll try to put together some good links for you -- I should have probably written earlier that much of my 'theory' of how they might impact the therapeutic relationship is just that -- a theory that makes sense to me. Not, scientifically proven yet, because it is such a new field of research.

Wikipedia Overview of Mirror Neurons:
http://en.wikipedia.org/wiki/Mirror_neurons

A pretty scholarly article, scan down to 'Mirroring Emotions and Sensations' What Do Mirror Neurons Mean? The Mirror neuron system and its role in interpersonal relations

A general science daily article:
How Mirror Neurons Allow us to Learn and Socialize...

I apologize if my first post was not totally topical -- just the idea of finding answers and having it all make sense, reminded me of this, and I wanted to help.