In short, watching an activity lights up the same area of the brain as ACTUAL MOVEMENT!
Thanks to Dr. Cobb for pointing this out at the (level II) I Phase training. Click below for links to the I Phase series.
Z Health Level II Update part 1
Z Health Level II Update part 2
Z Health Level II Update part 3
Z Health I Phase In Practice Update
Here is the Nova link below
Mirror Neurons on Nova