Last week, the Allen Institute for Brain Science revealed a complete map of the mouse brain down to details of the individual cell. This was the first project of an institute funded by Microsoft Corp. co-founder Paul G. Allen.

The new Allen Brain Atlas is being made available online without cost to neuroscientists studying brain circuits and chemistry, a potential boon to cancer and other disease research because of similarities between the brains of mice and human beings.

Because more than 90 percent of the same genes are found in mice and humans, the mouse brain map can be compared with genetic findings related to human neurological disorders. Moreover, the mapping project has shown that 80 percent of the body's genes are switched on in the brain, compared with 60 percent to 70 percent in previous scientific estimates, said Chief Scientific Officer Allan Jones.

The next project will be to develop a digital, three-dimensional, interactive map of the genes at work in a human brain's neocortex, the outer layer that is the seat of higher thought and emotion, using brains from cadavers as well as tissue removed during brain surgeries.