Chinese neuroscientists are beginning new research on changing the nature of brain neurons after disproving theories that neurons can change themselves to replace cells damaged by strokes or by diseases like Alzheimer's or Parkinson's.

A group of nine scientists from Shanghai and Guangzhou found that neuroblasts -- cells that transform into nerve cells or neurons -- did not generate into neurons like those that had been damaged.

Previously, scientists had hoped new neurons produced after a brain injury like a stroke could reach injured areas to replace damaged cells.

The Chinese study refuted the research direction, and indicated "external intervention" could induce neuroblasts to alter into appropriately functional neurons.

The study was explained in an article carried in the U.S.-based Journal of Neuroscience Wednesday.

Yang Zhengang, of Shanghai-based Fudan University, who led the study, told Xinhua on Thursday that his future study would focus on exploring genetic modification methods to trigger changes in cells that could replace the functions of the damaged ones.

"There is a bright future in using controllable transplant technology to make new cells carry certain genetic functions to replace cells damaged by brain diseases like Alzheimer and Parkinson," said the scientist.

In his research, Yang and his team marked new neurons in the brains of mice that had suffered strokes, and found they failed to produce the type of cells that control movement.

"The new neurons don't form the kind of spiny neurons like those before the injury, and they are also smaller in size," he said.

The human brain has about 100 billion neurons, which differentiate into about 10,000 types with different functions in the embryonic development period, he explained.

"You can't find a kind of super stem cell in an adult brain, which can differentiate into any type of neuron," said Yang.

But he hoped his new theory on intervention would ultimately bring hope to the treatment of brain diseases like Parkinson, which affects about 1.7 million Chinese.

(Xinhua News Agency April 23, 2009)