"The youngsters, ages 1 to 5, are shown smiling, laughing, fussing, crying; they appear alert and aware of what is going on around them. Yet each of these children was born essentially without a cerebral cortex. The condition is called hydranencephaly, in which the brain stem is preserved but the upper hemispheres are largely missing and replaced by fluid. Merker (who has held positions at universities in Sweden and the United States but is currently unaffiliated) became interested in these children as the living embodiment of a scientific puzzle: where consciousness originates. He joined an online self-help group for the parents of children with hydranencephaly and read through thousands of e-mail messages, saving many that described incidents in which the children seemed to demonstrate awareness. In October 2004, he accompanied the five on the trip to Disney World, part of an annual get-together for families affected by the condition. Merker included his observations of these children in an article, published last year in the journal Behavioral and Brain Sciences, proposing that the brain stem is capable of supporting a preliminary kind of awareness on its own. “The tacit consensus concerning the cerebral cortex as the ‘organ of consciousness,’” Merker wrote, may “have been reached prematurely, and may in fact be seriously in error.” Merker’s much-discussed article was accompanied by more than two dozen commentaries by prominent researchers. Many noted that if Merker is correct, it could alter our understanding of how normal brains work and could change our treatment of those who are now believed to be insensible to pain because of an absent or damaged cortex. For example, the decision to end the life of a patient in a persistent vegetative state might be carried out with a fast-acting drug, suggested Marshall Devor, a biologist at the Center for Research on Pain at Hebrew University in Jerusalem. Devor wrote that such a course would be more humane than the weeks of potentially painful starvation that follows the disconnection of a feeding tube (though as a form of active euthanasia it would be illegal in the United States and most other countries). The possibility of consciousness without a cortex may also influence our opinion of what a fetus can feel. Like the subplate zone, the brain stem is active in the fetus far earlier than the cerebral cortex is, and if it can support consciousness, it can support the experience of pain. While Mark Rosen is skeptical, Anand praises Merker’s work as a “missing link” that could complete the case for fetal pain. But anatomy is not the whole story. In the fetus, especially, we can’t deduce the presence or absence of consciousness from its anatomical development alone; we must also consider the peculiar environment in which fetuses live."