Jennifer Matthews: Zoot Wilson and his wife Marysa are back in step now -- having fun with daily dance lessons. But that wasn't always the case. Zoot has Lou Gehrig's disease. He's being treated for one of its side effects -- uncontrollable laughter.

Zoot Wilson: She said I laughed at the most inopportune times. I laughed at stuff that wasn't funny, but I was very frustrated. I knew I was frustrated, but the laughter part?

Marysa Wilson: He was humored by things that weren't necessarily appropriate or as funny as he thought them to be.

Jennifer Matthews: A therapy under study by neurologist Ralph Richter targets the pathways of the brain that control our emotions.

Dr. Ralph W. Richter: It may be in the frontal and temporal lobes of the brain. It may also be deeper in the thalamus, which in some sense the soul, is the seat of the soul, or emotion.

Jennifer Matthews: Zoot joined the trial and takes this drug every day.

Zoot Wilson: I'm just happier. My emotions are more even.

Dr. Ralph W. Richter: The benefit is toward quality of life. If you're not embarrassing yourself or feel embarrassed, you're going to feel better about yourself.

Jennifer Matthews: No longer on an emotional roller coaster, Zoot says he's enjoying himself with a sense of humor and some smooth moves on the dance floor -- and off. This is Jennifer Matthews reporting.