Marina Ziehn is the first scientist to show that multiple sclerosis-like disease in mice affects the part of the brain called the hippocampus, producing spatial memory symptoms that are characteristic of the disease. In addition, she's found that treatment with sex hormones, estrogens and androgens, is neuroprotective, lessening the degenerative effects of the disease.

Coming to UCLA for doctoral studies in 2005, Marina brought with her three interests: hormones in the brain, learning and memory, and disease. She chose UCLA because of the range of work under way here in the neurosciences. "I had a chance to integrate myself into several different neuroscience communities, so I could become a well-rounded scientist," she says, "and I could think differently about these questions that I had."

Marina started by using an experimental model of multiple sclerosis in mice, inducing the autoimmune disease and then studying its impact. In the key finding, Marina showed that the disease caused "shrinking of a region of the hippocampus that is critical to learning and memory." For mice, this meant difficulty in spatial learning. For people, it could mean losing the mental maps that help us navigate in the dark, return to our car in a parking lot, or give someone directions.

Based on the fact that women with multiple sclerosis improve during the "hormonal surges" of pregnancy, as well as other evidence, Marina decided to try treating her sick mice with sex hormones--and it worked. "The nice thing about this outcome," she says, "is that when you use endogenous hormones, it's easier to apply results to humans. You're not using strange drugs that would require years of testing."

And although Alzheimer's disease has a different mechanism--it's caused by a buildup of proteins in the brain, rather than autoimmune attacks on the myelin around neurons--it is also characterized by damage to the hippocampus. Hormone therapies may turn out to be successful treatments for both diseases.

Given her scientific achievements, it's worth noting that Marina may be just as proud of her mentoring and teaching activities. Two of the undergraduates she mentored in her lab are pursuing graduate degrees; one is pursuing an MD/PhD and the other a PhD. "I feel like I've succeeded," she says. "I've gotten more people to pursue higher education in science."

Although Marina was born in Texas, she spent her early childhood in Mexico, where both of her parents had gotten college degrees before they emigrated. Their experiences taught her "how to work hard through hardship," Marina says. Her mother is a particular role model. Having given up doctoral studies when she became pregnant, her mother nevertheless went on the become head of research and development for Mission Foods.

Perhaps because she was a scientist herself, Marina's mother was encouraging when her daughter started her own experiments. "When I was 5 or 6, I loved being outside," she says, "and the coolest thing for me was to collect bugs and plants in the garden. I was always curious about how living things worked, so I would open them up to find out."

Her childhood bug collection grew into an interest in math and science, and she started her undergraduate work at UC Santa Barbara as a pre-med biology major. "Somewhere along the way I took a course in psychology and neuroscience," she says, and she quickly decided that the brain "is way cooler than any other organ." She graduated as a biopsychology major in 2005 and started graduate work the same year.

Two years later, she was married, and two years after that, well into her doctoral work, she had a son. Her parents and her husband provided the support system, and along with her own determination, that made it possible to move forward with hardly an interruption. She was at work in the lab the day before she went into labor. "It's challenging, but I tend to work better when I have a lot on my plate," she says. "I know what I want out of a career, and I know what I want out of a family. If you want something, you make it happen.

Published in Fall 2010, Graduate Quarterly