I was following this thread, and went to work yesterday (I service 
MRI/CT scanners) to find the research people working with a watercooled 
thermode. ( http://www.medoc-web.com/thermode.html ). The peltier device 
heats up to cause pain, and the water cooling can rapidly change the 
temperature on it. The cable to the thermode has power for the peltier, 
a connection that looks like a thermocouple connector, and the 
feed/return water lines. There is a small (1ft x1 ft x1ft) water chiller 
that has the water at about 6 degs C. (An abnormal response to pain 
stimulus is an indicator of neurological dysfunction - or something like 
that)
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