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The mushroom cloud from an atomic explosion is the last one you would expect to have a silver lining.

But the spike in levels of the radioactive carbon isotope 14 (C14) created by nuclear tests in the 1950s has been put to good use in extraordinary research by a UWA graduate.

Professor Kirsty Spalding joined the Karolinska Institute in Stockholm after completing her PhD with Winthrop Professor Alan Harvey in Anatomy, Physiology and Human Biology 11 years ago.

Her work with Jonas Frisén on neurogenesis (a process by which new neurons are generated in the brain) has generated three papers in Nature and two in Cell , the world's most prestigious science publications.

It has implications for the treatment of neurodegenerative diseases associated with dementia, including Alzheimer's.

In the 1960s, scientists began to believe that the adult mammal brain could generate new neurons. It took until the 1990s for the discipline to accept that neurogenesis did in fact occur.

But it was not until June this year that Professor Spalding's decade of research was published in Cell , providing long-awaited proof. She and her colleagues used an ingenious approach, exploiting the fallout from the nuclear bomb tests between 1945 and 1963 as a yardstick.

Since 1963, above-ground nuclear testing has been banned and the amount of C14 in the atmosphere has declined. When a cell divides, it requires carbon which is ultimately taken from the atmosphere. Plants absorb C14 during photosynthesis and animals that eat them also take in radioactive carbon. When we eat the plants or the animals or drink their milk, we are absorbing it too. So the level of C14 in the cells of our bodies reflects that of the atmosphere.

Professor Spalding and her colleagues were able to birth-date cells from post-mortem tissue by measuring the amount of C14 in their DNA. The proportion of radioactive carbon in cells has been decreasing since 1963 and their work means the process can now be used to work out when cells were born. It was used to prove that new cells are born in the hippocampus (the part of the human brain that plays an important role in learning and memory) throughout the life of a human being.

"This is one of the most important papers I have read in years," Professor Harvey said. "Kirsty and her co-authors raise the tantalising possibility that reduced neurogenesis in the human brain may be a factor in psychiatric diseases. The possibility of therapeutic manipulation of neurogenesis to aid in the treatment of neurodegenerative diseases associated with dementia also has more substance now," he said.

Professor Harvey said Professor Spalding had gained a useful developmental biology background while working on her PhD at UWA.  She examined factors that ensured the survival of neurons during maturation of the visual system.  "Her work has always been related to nerve cells and what keeps them alive," he said.

His own work now concentrates on the central nervous system and developing therapies to promote regenerative responses of injured neurons in the adult brain and spinal cord.

He explained that neurogenesis supports greater plasticity of the brain, which it needs to be adaptable and to allow us to layer new memories on top of old ones.

"One of the surprises of Kirsty's research is that the new neurons born in our brains might not be exactly the same throughout our lives. There is a distinct possibility that the nature of the genes expressed in the cells may change over time."

There are also suggestions that continued neurogenesis may play a role in human behaviour.

"It certainly does in all the other mammalian species," Professor Harvey said. "This research opens up so many possibilities."

Professor Spalding has now changed the focus of her research and is employing the C14 dating system with fat cells. She has also published ground-breaking work in this field in Nature in 2011.  If fat cells, like brain cells, are constantly dying then being replenished, the process can hopefully be proved with C14 measurements.  If a therapy could be developed that could make the body destroy more fat cells than it creates, weight loss might be easier.

Professor Spalding persevered for a decade with her neurogenesis research. If anybody can find the key to weight loss, it could be her.