Neuroscientists, along with pretty much everyone else, have long suspected that Albert Einstein's brain was somehow unique. A new study now affirms these suspicions, showing that his genius may have arisen from the way the hemispheres of his brain were so freakishly well connected.
The new study is the first to detail Einstein’s corpus callosum — a thick band of nerve fibers that separates the cerebrum into left and right hemispheres. It connects the left and right sides of the brain, allowing for communication between both hemispheres, including the transmission of motor, sensory, and cognitive information.
In the new study, lead author Weiwei Men of East China Normal University’s Department of Physics developed a new technique to measure and compare the varying thickness of subdivisions of the corpus callosum along its length — the part of the brain where the nerves cross from one side to the other. The thickness of these subdivisions indicate the number of nerves that cross, thus showing how “connected” the two sides of the brain are in specific regions — regions that facilitate different functions depending on where the fibers cross along the length. For example, hand movements are represented toward the back, while mental arithmetic along the back.
After Einstein died, his brain was removed and photographed from multiple and unconventional angles. His brain was also sectioned into 240 blocks, from which many slides were created. Also, 14 photographs were recently recovered, giving neuroscientists yet more data to work with. And in fact, this information was used by Florida State University's Dean Falk to show that Einstein had a rather unique prefrontal cortex. Falk has also shown that inferior portions of the primary somatosensory and motor cortices were significantly expanded in his left hemisphere.
Albert Einstein’s corpus callosum, connecting the two cerebral hemispheres of the brain. The colors indicate the varying thicknesses of subdivisions of the corpus callosum (credit: Weiwei Men et al./Brain).
Using this information, Men compared Einstein’s brain to two different sample groups: 15 elderly men, and 52 men aged 26. This particular age was chosen was because that’s how old Einstein was in 1905 — his “miracle year” when he published four articles that revolutionized physics and our conceptions of space, time, mass, and energy.
The researchers discovered that Einstein's corpus callosum was thicker in the vast majority of subregions than the corresponding sections in the two controls. More specifically, Einstein’s corpus callosum was thicker in the rostrum, genu, midbody, isthmus, and (especially) the splenium compared with younger controls.
So, did the well-connected corpus callosum contribute to Einstein’s genius? Probably — but it's not the whole story. It's clear that he had other neurological attributes that contributed as well, including an exceedingly high ratio of glial cells and a prefrontal cortex of “extraordinary” size. Taken together, these traits may have allowed for his remarkable visuospatial and mathematical abilities, along with his predilection for thought experiments.
Read the entire study at Brain: “The corpus callosum of Albert Einstein‘s brain: another clue to his high intelligence?”