Our body images are pretty flexible, but they have their limits. For example, people do not usually regard their cars as their bodies when driving, although there are elements of an extended sense of self. I think the real resleeving trauma comes from trying to map neural pathways to the right body parts: we have a lot of learned reflexes and behaviors that use the body outside the nervous system as a part. When I flinch, my CNS "knows" how fast it is going to be and where I will end up, when I feel nervous it involves the right visceral signals and biochemistry, when I try to grip something the actual force is a combination of muscle strength, tendons resisting it, skin friction and hand geometry. If my body gets replaced many of these responses will be "off". A faster body might flinch almost spastically until my midbrain slowly learns to use a weaker signal. Feelings might be very strange if the visceral responses do not work as they should. Gripping with a slightly different hand is tricky. And all this strangeness comes at the same time. Plus, at least some people are going to have philosophical or emotional issues with their identity. The little things about the new body will make them even more nervous. In EP I also suspect a lot of the trauma is not the body itself but adjusting to the new brain running the ego. Imagine getting a slightly different level of neurotransmittors, transmission speed or even extra neural tissue (those mentons likely have built-in augmented dorsolateral prefrontal cortex). At the very least it would be like being jetlagged but given a cup of coffee: a bunch of contradictory, tiny differences.

King Shere wrote:

People can be become quite emotional if you harm or threaten something of "theirs" be it relatives, cars, fan poster or pets. Many People flinch when they see something "painful" or get emotional from it, I have regarded that as empathy. I wouldn't tie such distortion of "behavior" to the personal body/self identity, but rather to Social identity & group identification. More of a "group" psychology reaction, a mechanism that encourage group cohesion. For example: People in a crowd, follow its pattern & becomes a mob. Mimicking the others behavior & stand still -resulting in a mob of spectators. I wouldn't be surprised if the "mirror neurons" are the principal "culprit" behind the instincts of "social identity". ( despite not my field of expertise.)

They even have a term for this effect: [url=http://www.livescience.com/health/070617_touching_faces.html]mirror-touch synesthesia[/url]. This may be causing the effects that the original article was referencing.