How did Albert Einstein become a genius? Many researchers have assumed that it took a very special brain to come up with the theory of relativity and other stunning insights that form the foundation of modern physics.

A study of 14 newly discovered photographs of Einstein's brain concludes that the brain was indeed highly unusual in many ways. But researchers still don't know exactly how the brain's extra folds and convolutions translated into ability.

The story of Einstein's brain began in 1955 when the Nobel Prize-winning physicist died in Princeton, N.J., at age 76. His son Hans Albert and executor Otto Nathan gave the examining pathologist, Thomas Harvey, permission to preserve the brain for scientific study. Harvey photographed the brain and then cut it into 240 blocks, which were embedded in a resinlike substance. He cut the blocks into as many as 2,000 sections, and distributed slides and photographs of the brain to at least 18 researchers. With the exception of the slides that Harvey kept for himself, no one is sure where the specimens are now.

Over the decades, only six peer-reviewed publications resulted from these scattered materials. For the new study, published in the journal Brain, anthropologist Dean Falk of Florida State University teamed up with neurologist Frederick Lepore of the Robert Wood Johnson Medical School in New Brunswick, N.J., and Adrianne Noe, director of the U.S. Army's National Museum of Health and Medicine, to analyze 14 photos of the whole brain from the Harvey collection that have never before been made public. The paper includes a "roadmap" prepared by Harvey that links the photos of the brain to the 240 blocks and the microscopic slides prepared from them, in hopes that others will use them to do follow-up research.

The team compared Einstein's brain with those of 85 other humans described in the scientific literature. Although his brain, weighing 1230 grams, is average in size, several regions feature additional convolutions and folds rarely seen. For example, the regions on the left side of the brain that facilitate sensory inputs into, and motor control of, the face and tongue are much larger than normal; his prefrontal cortex -- linked to planning, focused attention, and perseverance in the face of challenges -- is also greatly expanded. "In each lobe, there are regions that are exceptionally complicated," Falk said.

Albert Galaburda of Harvard Medical School said that "what's great about this paper is that it puts down ... the entire anatomy of Einstein's brain in great detail."

But questions remain, including whether Einstein started off with a special brain, or whether doing great physics caused certain parts of his brain to expand. Falk said he thinks nature and nurture were likely involved. "Einstein programmed his own brain," he said, adding that when the field of physics was ripe for new insights, "he had the right brain in the right place at the right time."