When studying the brain, researchers often focus on its problems: addictions, mental illnesses and degeneration.

Gong Chen, assistant professor of biology at Penn State, spoke Saturday about the hopes and challenges of brain repair with a decidedly brighter tone.

"Today, I hope to show you some positive things about our brain," Chen said to an audience of about 325 in Thomas Building, concluding the 2007 Frontiers of Science lecture series.

The key to possible brain repair lies in stem cell research, Chen said. A highly controversial topic, stem cell research explores the use of stem cells as a way of repairing tissue, he said.

Chen explained to the audience that embryonic stem cells are preferred to adult stem cells for research.

He said all human embryonic stem cells were extracted from in-vitro fertilized eggs, which were voluntarily donated.

It was believed until recently that neurons in the brain could not be renewed. Research has shown that neural stem cells can divide and renew, or differentiate, Chen said.

"Ten to 30,000 new neurons are added into the adult brain every day, but only a small minority will survive and integrate into the adult neural network," Chen said.

To increase neuron generation, you need to exercise your brain, he said.

In the second part of the lecture, Chen focused on the possibilities of stem cell therapy. In the future, it may be possible to treat diseases ranging from Parkinson's and Alzheimer's disease to strokes and multiple sclerosis by using stem cell therapy.

Chen said research has focused mainly on Parkinson's disease -- caused by degeneration of a particular type of neuron called dopamine.

"More than 10 years ago, a group of scientists grafted human fetal tissue, which has a lot of dopamine neurons and perhaps some stem cells, into Parkinson's disease patients. This can alleviate some Parkinson's disease symptoms," he said.

Human fetal tissue is limited, but stem cells have the capacity to provide tissue supply for all patients, Chen said.

Chen said stem cell research is very promising, but much more research needs to be done.

"It will be 10 to 20 years until the therapy is mature enough to successfully apply it to patients," he said. "If I stand here again to give another lecture about stem cell research in 20 years, I am optimistic that I can tell you that several if not many diseases by then will be conquered by stem cell therapy."

Barbara Kennedy, who organized this year's lecture series, thought that the program as a whole was a success. Kennedy added that the lecture series receives "a ton" of positive feedback every year.

"It's like packaging a scientific study into an easy-to-listen-to format -- like a bedtime story for adults," she said.