Oliver Sacks

A new documentary, Oliver Sacks: His Own Life, chronicles the late neurologist's efforts to understand perception, memory and consciousness. Sacks spoke to Fresh Air in 2012.

The famed neurologist talks to Fresh Air about how grief, trauma, brain injury, medications and neurological disorders can trigger hallucinations -- and about his personal experimentation with hallucinogenic drugs in the 1960s.

The famed neurologist talks to Fresh Air about how grief, trauma, brain injury, medications and neurological disorders can trigger hallucinations — and about his personal experimentation with hallucinogenic drugs in the 1960s.