NEW YORK — Scientists restored some activity within the brains of pigs that had been slaughtered hours before, raising hopes for some medical advances and questions about the definition of death.

The brains could not think or sense anything. By medical standards, they'd been dead for four hours by the time scientists began pumping a special artificial blood through them in their lab.

Yale University researchers reported Wednesday in the journal Nature that they were able to restore activity in some brain cells. Further work might lead to new therapies for stroke and other conditions, as well as a new tool for studying the brain.

AP