If we are asking “how does the brain work?” we have to start somewhere. One starting point is the possible correlation between brain morphology—its gross dimensions and shape, and the cellular makeup of the brain—and the cognitive abilities of a person. This could occur at each end of the spectrum. For those with diseases that affect cognition, like schizophrenia, depression, or autism, are there specific changes in brain morphology? In other words, could we look at a brain removed at autopsy, paying attention to both the gross morphology and microscopic findings, and say that person had schizophrenia? The answer is no. One of the problems in these diseases of cognition is that they do not have specific pathological signatures as occurs in Alzheimer’s disease or Parkinson’s disease.
At the other end of the spectrum are people who have superior mental abilities that set them apart from the rest of us. How might their brains be different? A striking example is the continuing analysis of Einstein’s brain, which has been going on for more than 50 years. Einstein died in 1955 at age of 76, from a ruptured aortic aneurism. His brain was removed and originally studied by a local pathologist, Thomas Harvey, who became the custodian of the brain. Dr. Harvey has been criticized by some for keeping control of the brain and not turning it over to neuropathology experts, particularly the Armed Forces Institute of Pathology in Washington D.C. In fairness to Dr. Harvey, he did photograph and make sections of the brain, with help from experts at the University of Pennsylvania, and subsequently made this material available to the pathological gurus of the time. The consensus was that Einstein’s brain fell “within normal limits for a man his age.” In retrospect, it looks like these pathologists were focusing on disease and not deviations from normal.
Their findings stood until two reports, one in 1985 by Marian Diamond and the other in 1999 by Sandra Witelson, were presented. Both focused on the parietal lobes, a part of the brain involved in processing sensory information, and also with appreciation of spatial orientation. Diamond came to the conclusion that Einstein had different cellular morphology with an excess of glial cells, not an excess of neurons. Witelson concentrated more on the gross morphology, emphasizing that the anatomy of Einstein’s parietal lobes were different, with bigger areas that could have enhanced his spatial cognition, mathematical thought, and imagery of movement. This expansion was at the expense of language areas (Einstein is reported to be delayed in speaking; he did not talk until age three).
What reignited this story is the availability of an additional 14 photographs of Einstein’s brain. This report is based on an article in the journal Brain. The investigators compared the morphology of Einstein’s brain to 85 brains of other, presumably more “normal” people. This report in Brain is a detailed comparison of widespread regions of the brain. The authors conclude that the differences in Einstein’s brain are more widespread, but the emphasis on differences in parietal lobes, as highlighted by Witelson, is probably correct. On the basis of these new findings in the gross morphology, these authors suggest that careful analysis of the cellular makeup of selected areas be carried out. Dr. Harvey had cut the brain into 240 blocks from which slides were, and could be, made. This is probably happening now.
The attempts to draw correlations between both gross and micromorphology of the brain and cognitive functions, either superior or altered, have a long and speculative history. Let us assume that everyone someday agrees on what makes Einstein’s brain different—how do we go from there to his unique mind? One approach is to find other brains that have similar changes as Einstein’s and ask if these people had cognitive performances that were enhanced. This may sound simple, but will be hard to accomplish.
It may also be that a 126-year-old brain that has been sitting in preservative for 50 years cannot be further analyzed. One can then ask, if Einstein were alive today what could we do to try to see how he ticks? One of the advances in our thinking about the brain is that the billions of nerve cells don’t function as a region but form interactive networks, integrating information. Perhaps it was Einstein’s interconnections that were different, partly on the basis of how his brain developed and partly on how he used it. Which came first: the unique cognitive abilities or the response of the brain to these abilities? Advances in brain imaging might give us a clue. Further, Einstein was an accomplished violinist from an early age. He, like other violinists, had expansion of the right motor area in the cerebral cortex, linked to the left, fingering hand, a response of his brain to usage.
Would using your brain in a specific way also change its morphology? I wonder if there is an area of my parietal cortex that is getting bigger as I watch the NFL on Sundays, crowding out more productive areas. I am sure my wife thinks so.
For those who would like to read more about the issue of brain morphology and intellect, there is a marvelous article in the January 2001 issue of the Dana publication Cerebrum by Frederick Lepore, one of the authors of the recent paper in Brain.