(April 24) - Two British celebrities have signed on to donate their brains for Parkinson’s research as part of a national appeal for others to do the same.

The British Parkinson’s Disease Society (PDS) is asking people across the U.K. to agree to donate to the largest Parkinson’s brain bank in the world, ABC News reported.

TV host Jeremy Paxman and actress Jane Asher, who is also the president of PDS, are two of the 1,000 people in the country who have made the pledge. But that’s not enough, Asher said in a statement.

“It's vital that we secure more potential donors as this will help us move closer to a cure for what can be a debilitating and distressing condition," she said.

There is no known cure for Parkinson’s, a progressive neurological disease that causes a loss of nerve cells in a section of the brain key to the body’s ability to control movement. Symptoms include tremors, slow movement, stiffness and balance problems. Sufferers also may be depressed, have muffled speech and have trouble walking.

Asher’s brother-in-law has the disease. In the United States, Parkinson’s sufferers Michael J. Fox and Muhammad Ali are two of the biggest faces of the disease. Pope John Paul II, who died in 2005, also suffered from Parkinson’s.

One in 500 Britons has Parkinson’s. About 1.5 million Americans are afflicted, according to the U.S. National Parkinson Foundation, and another 60,000 new cases are diagnosed each year. It usually develops after the age of 65, but 15 percent of those diagnosed are younger than 50. Fox was diagnosed at 30.

Advocates say more brain research is needed in the hunt for a cure. But a PDS-commissioned survey found that although more than 60 percent of Britons are comfortable donating a heart or kidney, just 7 percent are comfortable with the idea of brain donation. Even the chief executive of the PDS told ABC News that he had to talk with his family at length about his decision to donate his brain.

Research using donated brain tissue has already led to medical advances, including the development of a drug that has “revolutionized” the controlling of symptoms, PDS said.