Asking about dividing cells

The adult brain stops growing but keeps on producing large numbers of new nerve cells, so why doesn't it blow up?

Such are the complex matters under discussion at Trinity College Dublin at a three-day conference, "Life and Death of the Brain". Organised by former members of Trinity's Department of Genetics, it has attracted leading experts in neurobiology.

The opening lecture was given yesterday morning by Dr Derek van der Kooy of the University of Toronto who described his research into stem cells, the general-purpose cells which are affected by specific growth factors to become the various types of nerve cells.

These cells are plentiful in the embryonic brain, but their numbers drop at maturity. Active stem cells remain, however, in a layer a few cells thick near the lateral ventricle where they divide and multiply every 12 hours, Dr van der Kooy explained.

"Why doesn't you brain explode," he asked delegates. Stem cell numbers are highly regulated, he said, and half of all newly divided cells die immediately, leaving the total number unchanged. These dividing stem cells have been found elsewhere in adults, he said, including the spinal cord and in the eye.

The conference's opening address was from the Vice-Provost of Trinity, Prof David McConnell, who said neurobiology would be one of the most influential research areas of the 21st century. "We are on the brink of some remarkable discoveries," he said.

The conference was organised by two Trinity graduates, Dr Kevin Mitchell, now of the University of California, San Francisco, and Dr John Connelly, of Fondation Jean Dausset, CEPH, Paris.

They are now involved in neuro-biological research and wanted to bring international experts to Dublin to encourage more Irish researchers in the field, Dr Mitchell said.

The title describes the conference agenda which covers how the brain develops, how it functions and what happens when it goes into decline through age or disease. About 40 delegates have come from the US, France, Switzerland, Canada and Britain.