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 I found our discussion on motion sickness and corollary discharge rather interesting because I have always wondered why some people get motion sickness and others don't.  Are the nervous systems of some people just better at realizing that even though the person is not moving, the car is?  My mom does not get motion sickness at all, she can be crocheting or reading a fine print book in the car and be perfectly fine.  My brother, on the other hand, cannot read or do anything else in the car other than sleep.  So does this mean my mom's nervous system is better at blocking out the unexpected signals received while sitting in a car?  Does that make her nervous system faulty? Since our bodies rely on pain to tell us something is wrong, would not having motion sickness mean that even when what the nervous system expects and the actual signals received do not match, the body can accept that?

Corollary discharge signals can also be applied to watching movies in IMAX/3D.  I saw a move in IMAX/3D this weekend and it definitely got me thinking about the actual signals we receive versus what is actually there.  So even though the movie was technically in 2D, due to visual effects, the images virtually came to life.  What I found interesting was that when an object was being thrown at a character, most people in the audience ducked.  It is instinctual to avoid objects that are coming at your head, but we were all sitting in a movie theater, we all knew that the screen could not actually harm us, and yet most of us still flinched.  I have a friend that cannot even watch movies in 3D because she gets headaches from it.  I guess watching 3D movies can be interpreted as a type of motion sickness because our nervous system is expecting a movie on a large screen but in 2D while the actual signals being interpreted are of 3D figures coming out of the screen.  

An interesting article on Phantom limb for anyone who's interested: http://www.scientificamerican.com/article.cfm?id=phantom-limb-cure-retrain-brain