STAFF WRITER As love-struck couples shower their special someones with cards, gifts and flowers for Valentine's Day, a trio of researchers at Rutgers University have taken up the task of unlocking the mysteries of love and human sexuality that have perplexed men and women since the beginning of time. The brain and sex Barry Komisaruk of Maplewood, Board of Governors distinguished service professor and a professor in the psychology department at Rutgers in Newark, has been studying the brain activity related to sexual response in women and men for several decades.