Rita Levi-Montalcini

Rita Levi-Montalcini was one of the oldest living Nobel laureates.

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Rita Levi-Montalcini not only was one of the world's preeminent brain scientists, she was also the oldest living Nobel laureate until her death on Dec. 30, 2012. Born in Italy in 1909, Levi-Montalcini attended medical school despite her father -- an electrical engineer and mathematician -- initially forbidding her from pursuing higher education [source: Levi-Montalcini]. After she earned her degree in medicine and surgery in 1936, Levi-Montalcini decided to concentrate on neurology, rather than practice medicine. The disruption of World War II forced the brilliant Italian to dodge dangerous military zones and continue her research in hiding, even serving briefly as a military medical doctor.

After the dust settled from the war, Levi-Montalcini and her research partner Stanley Cohen sought to figure out how an embryo's nerves proliferate throughout a growing body [source: Abbott]. In the process, they discovered nerve growth factor, the key protein that stimulates neural development and growth. The breakthrough garnered the pair a Nobel Prize in physiology or medicine in 1986; Levi-Montalcini was 77 years old. On the eve of her 100th birthday in 2009, she told the Times of London newspaper that she still showed up for work at the European Brain Institute, which she founded, every day [source: Owen]. Asked for advice on how to reach that centenarian threshold, Levi-Montalcini recommended a three-part regimen of minimal sleep, limited food intake and always keeping the brain active and interested [source: Owen].