To look at her, you would never know that Isabelle X is missing a piece of her brain. Ten years ago, a swollen blood vessel burst in her left temporal lobe. When the surgeon opened her skull to excise the damaged tissue, he noticed another dangerously swollen vessel on the right side and prudently snipped that one out too. The operation saved her life, but at the price of a good portion of cerebral cortex. Now she sits in front of a video camera: a poised, attractive woman in her late thirties, wearing a stylish beige jacket over a black chemise. She doesn’t slur her words or stare vacantly. No muscular tic or twitch haunts her perfectly made-up face. What is most astonishing about Isabelle, in fact, is how utterly normal she is. At least until the music starts.
O Tannenbaum, O Tannenbaum, how lovely are your branches!
Plucked out on a piano offscreen, without lyrics, the old Christmas chestnut is instantly recognizable--or should be. When an investigator asks Isabelle to name the tune, she hesitates.
A children’s song? she answers.
Try this one, says the investigator.
