The beautiful and deeply religious Madame de Tourvel is so distraught after cheating on her husband in the 1782 novel “Les Liaisons Dangereuses” that she blacks out the betrayal altogether, arriving at a convent with no idea of what had brought her there. Soon the horror of the infidelity rushes back, in all its incriminating force. More than two centuries later, she has become part of a longstanding debate about whether the brain can block access to painful memories, like betrayals and childhood sexual abuse, and suddenly release them later on. In a paper posted online in the current issue of the journal Psychological Medicine, a team of psychiatrists and literary scholars reports that it could not find a single account of repressed memory, fictional or not, before the year 1800. The researchers offered a $1,000 reward last March to anyone who could document such a case in a healthy, lucid person. They posted the challenge in newspapers and on 30 Web sites where the topic might be discussed. None of the responses were convincing, the authors wrote, suggesting that repressed memory is a “culture-bound syndrome” and not a natural process of human memory. Madame de Tourvel “is the closest we got to a winner,” said Dr. Harrison Pope, a professor of psychiatry at Harvard and the lead author of the paper. But her amnesia, he said, was too brief to qualify.