Therapy aimed at the other major feature of the disease, toxic deposits of a protein called beta-amyloid, is just now moving into the clinic, said William Thies, vice president for medical and scientific affairs at the Alzheimer's Association. That therapy developed from animal experiments similar to the one reported by Ashe and her colleagues, he noted.

Her team "have produced a tool with which people can begin to explore whether limiting tau can be a good endpoint," Thies said.

Mice in the study were trained to swim to a submerged platform in a pool of water. They lost the ability to find the platform when the damaging gene was in action and regained it when the gene was turned off -- a surprising gain in memory.

"Many of us have thought that the brains of Alzheimer's patients have live neurons, dead ones and sick ones," Thies said. "If you remove whatever is irritating the sick ones, they can get better."

While the new study centered on tau, "maybe the ultimate treatment is something that reduces the accumulation of both amyloid and tau," Thies said.

The form of tau that may become a target for treatment is unknown, Ashe said. "Maybe there are other abnormal forms of tau that have not been found," she said. "After all, these are not even visible under the microscope."

And the same can be true of amyloid, Ashe said. "The important message here is that we need to known which forms of beta-amyloid and which forms of tau we want to target," she said.

More information

Find out more about advances in Alzheimer's research at the Alzheimer's Association.

Community programs get older people moving

Programs that increase older adults' exercise levels in the research setting can work in the real world as well, according to a new study.

Researchers found that two exercise programs that have proved effective in studies also worked when offered at the local YMCA or other community centers. Unlike traditional exercise classes, the programs taught older adults ways to change their behavior and fit physical activity into their daily lives. Overall, the study found, participants in each program bumped up their exercise levels, shed a few pounds and reported less stress and depression.

The findings are published in the July issue of the American Journal of Public Health.

Many studies have examined ways to ramp up older adults' exercise levels, but programs that work in a research setting do not necessarily translate to the real world. In the new study, researchers led by Dr. Sara Wilcox of the University of South Carolina in Columbia looked at whether two such programs are effective when offered by community centers, local health departments and health insurance plans. The study included 838 men and women age 50 and older who participated in one of the two interventions. One was a telephone-based program developed by Stanford University, in which counselors gave advice on breaking down barriers to exercise and safely fitting activity into daily life. The second program, developed by the Cooper Institute in Dallas, was similar but used group meetings instead of phone calls.

Through surveys before and after the programs, Wilcox and her colleagues found that participants increased their amount of moderate and vigorous exercise by more than 2 hours per week, on average.

At the same time, their depression and stress levels dipped, as did the groups' average weight. The findings, according to the researchers, show that exercise-promoting programs can be successfully moved from the lab to real life. "All too often," they note, "effective behavioral programs do not impact communities because they are never translated broadly."