Lifechangers: Explaining Mary Tyler Moore's Brain Tumor

Veteran actress Mary Tyler Moore recently underwent successful brain surgery to remove a benign tumor. "Extra" Lifechanger Dr. Neil Martin explains the procedure.

"This kind of tumor is on the lining of the brain, and when it presses against the brain, it can cause seizures, memory loss, numbness, personality changes and blurred vision."

Find out more here -- and why her former co-star, Dick Van Dyke, is thrilled.