I may have this mixed up, but in the human anatomy class I took last year, pain receptors and other sensory infomation, etc. is relayed through the nervous system to the brain and back. Correct me if I'm wrong, but to actually have any responsiveness to the environment in a physical sense, wouldn't there have to be brain activity as tracked on an EEG? I'm no expert, but if I paid any attention, that's what I seem to remember.