Roche AG and Eli Lilly and Co., two drugmakers racing to develop treatments for some of the least understood brain disorders, may gain the most from a U.S. government boost in funding to fully map the human brain.

The National Institutes of Health is in the planning stages of a massive effort called the Brain Activity Map to understand how neurons actually process information, Story Landis, director of the agency’s Neurological Disorders and Stroke division, said Monday. It may take at least five years to develop the tools needed to map out all this information, she said.

“A lot of people see neurological research as the last great frontier in biomedical science,” Landis said in an interview. “There are lots of people looking at individual circuits, this would take the science to a whole new level.”

Better funding should improve the odds for finding effective Alzheimer’s, Parkinson’s and autism treatments, which so far have been plagued by failures because much of how the human brain works remains a mystery. There have been 101 unsuccessful attempts to develop a treatment for Alzheimer’s disease since 1998, including recent setbacks by Pfizer Inc., Johnson & Johnson and Lilly, according to the Pharmaceutical Research and Manufacturers of America.

“This attention to neuroscience research is exciting,” said Luca Santarelli, the head of neuroscience at Basel, Switzerland-based Roche, Europe’s second-largest drugmaker by sales. “Advancements in the understanding of the molecular and circuit basis of brain disorders will dramatically advance the development of treatments for patients.”

Alzheimer’s, the most-common form of dementia, is the sixth-leading cause of death in the U.S., according to the Alzheimer’s Association. The number of people with the disease is expected to double within 20 years as the world’s population ages, to as many as 65.7 million in 2030 and 115 million by 2050, the Geneva-based World Health Organization said last year. There is no treatment to cure or slow the disease. Current therapies address only symptoms.

Roche has 16 drugs in development for neurological disorders, including four for Alzheimer’s disease and two for autism. Indianapolis-based Lilly is working on 10 neurosciences drugs, while New York-based Pfizer has 11 in testing, including two for Alzheimer’s.

The NIH initiative would be akin to what happened with the Human Genome Project, where DNA sequencing was already occurring at a small scale before the project to map the entire human body was started, said George Church, a genetics professor at Harvard Medical School and director of the Personal Genome Project.

While researchers can already track the activity of perhaps 100 or so brain neurons at a time, the new opportunity is to connect those on a large scale and then measure activity at the detail level and the whole brain level, Church said.

“This is about basic technology as well knowledge,” Church said in a telephone interview. “We stand at the doorway of a fundamental intersection of nanochemical sensors that can read or write neurons and synthetic biology. It’s overripe for this merger.”

Neuroscience and related fields of biology get about $500 million in funding from NIH and other foundations each year, Church said. The Obama administration plans to make a budget proposal to Congress next month for billions of dollars in spending for the project, the New York Times reported earlier. A spokesman for the White House said he couldn’t immediately comment on any budget plans.

President Barack Obama mentioned in his State of the Union address last week the return on investment seen from mapping the human genome.

“Every dollar we invested to map the human genome returned $140 to our economy, every dollar,” Obama told Congress in his Feb. 12 speech. “Today our scientists are mapping the human brain to unlock the answers to Alzheimer’s.”

The challenge for Obama, a Democrat, is getting support from congressional Republicans who are already at an impasse with the president in negotiations to head off $1.2 trillion in automatic, across-the-board spending cuts. House Speaker John Boehner has already dismissed most of Obama’s ideas on budget and economic matters from the speech.

“Understanding the human brain is the great big challenge of the next century,” Richard Frackowiak, co-director of the Human Brain Project, a European partnership that has also been collecting brain data. “There’s every reason to believe that there will be fantastic wealth generation and industrial change that will follow major advances in this field.”

The European Union said last month it would give $1.3 billion to researchers across Europe to integrate data on the human brain to create supercomputer-based models and simulations. Unlike brain mapping programs, it isn’t a data generation project, and aims to use existing data to “predictively reverse engineer the brain,” said Henry Markram, coordinator of the project.

Technology already exists that lets researchers and doctors work with the brain, such as Cochlear implants and devices that can transform neural activity into signals that control robotic limbs. The brain activity map project could not only increase investigators understanding of the brain but dramatically improve existing technology, Church said.

“You get the feeling that this is building momentum the same way the genomic project did,” Church said. “There is a lot of excitement. I have little doubt this will be a big project.”