From a new study in the Journal Brain:

 Although the brain is only average in size, several regions feature additional convolutions and folds rarely seen in others. 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; and his prefrontal cortex — linked to planning, focused attention and perseverance — is also greatly expanded.

“In each lobe,” including the frontal, parietal and occipital lobes, “there are regions that are exceptionally complicated in their convolutions,” Falk says. As for the enlarged regions linked to the face and tongue, Falk thinks that this might relate to Einstein’s famous quote that his thinking was often “muscular” rather than done in words.

Although this comment is usually interpreted as a metaphor for his subjective experiences as he thought about the universe, “it may be that he used his motor cortex in extraordinary ways” connected to abstract conceptualization, Falk says.

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 thin sections for microscopic study, and in subsequent years distributed slides and photographs of the brain to at least 18 researchers around the world. With the exception of the slides that Harvey kept for himself, no one is sure where the specimens are now, and many of them have probably been lost as researchers retired or died.