A global map of the mind: An electronic database may help to explain how the brain works, says Ruth McKernan

YOU MAY not have guessed it, but British and US scientists have designated the Nineties the 'decade of the brain'. They are expecting huge advances in the understanding of mental illness in the next few years.

American scientists are planning to produce a detailed reconstruction of the human brain to help. This will be a 'corporate' brain, stored on computer, acting as a central resource for researchers around the world to refer to.

According to Dr Stephen Koslow, director of the US National Institute of Mental Health (NIMH) and co-ordinator of the project, the electronic brain will describe the geography and chemistry of the 100 billion cells that make up this complex organ. He says: 'Our ultimate goal is to have all the information known about the brain in a computer system which will be a three-dimensional representation of the human brain in both normal and diseased states.'

The project is the equivalent of making a detailed map of the world - a massive task, but indispensible once achieved. Since the number of cells in the brain is about 20 times the number of people on our planet, a complete analysis of the distribution and function of all the people in Britain would represent only a tiny fragment of the data.

The only other international biological project of comparable size is the 'human genome project'. This project is mapping every gene on the 23 pairs of human chromosomes.

In many organs of the body, such as the liver, most cells are identical. But in the brain, groups of cells have different chemical characteristics and specialised functions. Most of the brain's cells make direct contact with up to 100 others. Indirect links eventually join all the cells in one huge network. 'To really try and understand how the brain works we must put all this information together and consider the brain as a whole,' Dr Koslow told the annual meeting of the international Society for Neuroscience in California recently, when he unveiled the project.

The global scheme, called the Human Brain Project, should help clinicians to diagnose brain disease. More people are admitted to hospital in the Western world with mental illnesses than with cardiovascular disorders or cancer. By tapping into a global database of brain scans and case histories, doctors will be able to make more informed judgements on diagnosis and treatment.

The networks of cells in the brain form an intricate pattern of pathways and tracts. Just as computer studies of traffic flow in cities can help to pinpoint the source of traffic jams, a computer model of the brain may help to identify which pathways are involved in mental illnesses.

'The computer will be able to display neuronal circuits and could be used to define the pathways for anxiety or depression,' says Dr Koslow. The project should help scientists to predict the side-effects of new drugs.

It will also provide information on which part of the brain controls each of the body's functions. Such knowledge would make it easier for doctors to predict, for example, which abilities a patient might lose after having a brain tumour removed.

Unlike the genome scheme, the international brain project is primarily a job of assimilating known information, rather than generating new data. Some neurobiologists are wary that funding this type of 'big science' project may take money away from basic research.

Early work on the project is scheduled to begin next year, when 15 research institutes and agencies of the US government are expected to join with the NIMH - even the Central Intelligence Agency is interested.

Many other countries, including Britain, have been approached for financial support. The Medical Research Council, which allocates government funds, believes the scheme is potentially exciting, but has no plans to set aside money for it. Dr Peter Dukes, secretary of the neuroscience board of the MRC, says: 'We have an extra pounds 4.5m available from the Office of Science and Technology, some of which we could put towards this project, but we would need to see a well-justified demand from our scientists.'