Oprah Winfrey visits California's Pelican Bay State Prison and the infamous Security Housing Unit that has been controversial for years and once earned the "supermax" prison the nickname "Skeleton Bay." She reports on conditions in the "SHU" isolation unit that critics charge constitutes torture. Winfrey's report will be broadcast on 60 Minutes Sunday, Oct. 22 at 7:30 p.m. ET and 7 p.m. PT.

California, which long sent thousands of inmates to solitary confinement, is now on the leading edge of a reform movement aimed at curtailing the practice of limiting prisoners' human contact – which many say can cause mental illness.

60 Minutes has reported on the prison's SHU before. Mike Wallace went there in 1993 to report on conditions at a time when the state touted Pelican Bay as "the wave of the future" in corrections. In another report in 2005, Lesley Stahl examined how gang members in the SHU still managed to communicate and run their murderous enterprises on the streets.

Oprah Winfrey on assignment for "60 Minutes" inside California's Pelican Bay Prison CBS News

Winfrey appeared today on CBS This Morning to talk about her second 60 Minutes story and also discuss her new book, "The Wisdom of Sundays: Life Changing Insights from Super Soul Conversations."