"A neurosurgeon once told me about operating on the brain of a young man with epilepsy. As is customary in this kind of operation, the patient was wide awake, under only local anesthesia, while the surgeon delicately explored his exposed cortex, making sure that the parts tentatively to be removed were not absolutely vital by stimulating them electrically and asking the patient what he experienced. Some stimulations provoked visual flashes or hand-raisings, others a sort of buzzing sensation, but one spot produced a delighted response from the patient: "It's 'Outta Get Me' by Guns N' Roses, my favorite heavy metal [sic] band!"I asked the neurosurgeon if he had asked the patient to sing or hum along with the music, since it would be fascinating to learn how "high fidelity" the provoked memory was. Would it be in exactly the same key and tempo as the record? Such a song (unlike "Silent Night") has one canonical version, so we could simply have superimposed a recording of the patient's humming with the standard record and compare the results. Unfortunately, even though a tape recorder had been running during the operation, the surgeon hadn't asked the patient to sing along. "Why not?" I asked, and he replied: "I hate rock music!"Later in the conversation the neurosurgeon happened to remark that he was going to have to operate again on the same young man, and I expressed the hope that he would just check to see if he could restimulate the rock music, and this time ask the fellow to sing along. "I can't do that," replied the neurosurgeon, "since I cut out that part." "It was part of the epileptic focus?" I asked, and he replied, "No, I already told you – I hate rock music.""