A man that has been in a persistent vegetative state for 12 years was asked questions while undergoing an fMRI (functional MRI) of brain. Researchers obtained correct responses with limited questioning that suggested to them meaningful brain activity. In fact, PET scans of vegetative patients, although they demonstrate reduced brain glucose utilization compared to healthy subjects...the appearance of their scans resembled healthy persons under anesthetic.
Possibly even more striking, the vegetative patient when asked questions about a change in status a close family member related to the birth of a niece...responded correctly suggesting additionally that new memories might be able to be formed even in these patients.
Special thanks to Amir A. Aminmadani,BS...aspiring neuroscientist for sharing this with me.