In Plain Sight, Season 5

Mary:
[voiceover] There's a phenomenon some people experience, those who've lost an arm or a leg, called "phantom limb". They feel pain, heat, cold, even movement, despite the fact that, strictly and scientifically speaking, there is no "there" there. It's as if the body can't accept that something so essential so natural a part has moved on... The memory of what had always been there so strong that even in its clear and sudden absence, the connection cannot be denied.