What happened to Nevil parents in Harry Potter?

In the Harry Potter series, Neville Longbottom's parents, Alice and Frank, are described as having been tortured to insanity by Bellatrix Lestrange and other Death Eaters during the First Wizarding War. As a result, they have been permanently hospitalized at St. Mungo's Hospital for Magical Maladies and Injuries, where Neville visits them regularly. The attack on Neville's parents is one of the motivations behind his courage and determination in the fight against Lord Voldemort and his followers.