http://www.kqed.org/.stream/anon/radio/quest/2009/11/2009-11-30-quest.mp3
People with pseudobulbar affect -- a neurological condition common in patients with Lou Gehrig's disease -- have overwhelming emotions at inappropriate times: They laugh uncontrollably at funerals, cry even when they aren't sad. Scientists at UC San Francisco believe that by putting these people into MRI scans, they can learn more about how emotions are created and controlled in the human brain -- and what happens when those systems break down.