Scientists claim to have created the world's first digital brain map that they say will help doctors better understand a range on conditions such as Alzheimer's disease, autism and mental health disorders.

A team at the Allen Institute for Brain Science has created the computerised map after spending four years piecing together minute details from brain tissue including millions of genes, the 'Wall Street Journal' reported.

The brains were chopped up into sections to extract the RNA and find the 25,000 genes present in the human genome.

Each detail was loaded into a computer to provide the exact directions from oner point of the brain to another.

In fact, the scientists hope the map will help doctors understand how the brain works and aid new discoveries in disease and treatments.

"Until now, a definitive map of the human brain at this level of detail simply hasn't existed. For the first time, we have generated a comprehensive map of the brain that includes the underlying biochemistry," Allan Jones from the Institute was quoted as saying.

The institute is making the atlas freely available at www.brain-map.org as a resource for scientists studying brain diseases, along with a set of computational tools to help them analyse the data for clues to conditions such as Alzheimer's disease, autism and mental health disorders like depression.

Doctors have for years struggled to link symptoms of the diseases they study to the biochemistry of genes that might be responsible for them. They have therefore been unable to get brain's full picture to tackle the diseases.

In the latest research, the scientists catalogued 1,000 "landmarks" in each of two brains then linked those tissues to thousands of genes they work in conjunction with to neural development and function.

By using the map it is possible to see how strongly or weakly different genes act on different parts of the brain.

"The Allen atlas tells you where a gene is turned on in the brain and that's why it is important. We feel confident that we are giving a good average picture of the human brain to the people who are mining this data," neurologist Jeffrey L Noebels was quoted as saying.

The scientists now want to look into another eight brains by the end of the year in order to better understand the differences between people. They will also research the brain of women to see what differences are present.