1.   By contrast, people who are depressed have greater activity in their right prefrontal lobe.

2.   During those two minutes, the smokers showed a strong increase in left prefrontal lobe activity.

3.   The left prefrontal cortices of self-described happy people were bursting with nerve-cell activity while those who were depressed had more active right prefrontal lobes.

4.   Their right prefrontal lobes went ballistic as they got closer to making the speech.