The Exceptional Brain of Albert Einstein

Sandra F. Witelson, Debra L. Kigar, Thomas Harvey
Department of Psychiatry and Behavioral Neuroscience
McMaster University, Hamilton, Ontario

Excerpted with permission from: The Exceptional Brain of Albert Einstein,
The Lancet 1999; 353: 2149-53

Preservation of Einstein's Brain

Einstein died of a ruptured aneurysm of the abdominal aorta in 1955 at the age of 76 years. Within 7 hours of his death, his brain was removed at necropsy, fresh weight was measured, perfusion of 10% formalin by injection into the internal carotid arteries was carried out, and the whole brain was then freely suspended in 10% formalin for fixation and subsequent study. No significant neuropathology was seen on examination (gross or microscopic). After fixation, caliper measurements were made directly from the brain. The cerebral hemispheres were cut into approximately 240 blocks, each about 10 cm cubed. The blocks were embedded in celloidin, and histological sections were made.

Control Brain Specimens

The control group consisted of all male specimens available at the time (n=35) in the Witelson Normal Brain Collection based at McMaster University. The brains were from research volunteers with normal neurological and psychiatric status and normal cognitive ability. The mean Full Scale IQ score on the Wechsler Adult Intelligence Scale was 116 (SD 9). Einstein's brain was also compared with the brains of 8 men aged 65 years or more (mean 68) for brain measures known to change with advancing age. Although women have smaller brains than men, for purposes of descriptive analysis of gyral morphology, Einstein's brain was also compared with 56 female brains.

Measurements

Direct caliper measurements were made both from Einstein's brain and from the control brains. Other measurements were made from calibrated photographs. We measured baseline values for overall dimensions of the brain, including variables for which there are published data (e.g., weight, corpus callosum size); measures involving parietal regions important for visuospatial cognition and mathematical thinking; and, for comparison, measures of frontal and temporal regions. Statistically significant differences between Einstein and the control group were defined as those measures at least 2 SDs from the control mean.

Discussion

The gross anatomy of Einstein's brain was within normal limits with the exception of his parietal lobes. In each hemisphere, morphology of the Sylvian fissure was unique compared with 182 hemispheres from the 35 control male and 56 female brains: the posterior end of the Sylvian fissure has a relatively anterior position, associated with no parietal operculum. In this same region, Einstein's brain was 15% wider than controls. These two features suggest that, in Einstein's brain, extensive development of the posterior parietal lobes occurred early, in both longitudinal and breadth dimensions, thereby constraining the posterior expansion of the Sylvian fissure and the development of the parietal operculum, but resulting in a larger expanse of the inferior parietal lobe.

Figure 2: Lateral photographs and tracings of left (solid line) and right (dashed line) superimposed hemispheres of a typical control male brain (A,B,C) and the brain of Einstein (D,E,F).

The photographs of the control brain show the parietal operculum in the left (stippled) and right (hatched) hemisphere, situated between the postcentral (PC) sulcus and the posterior ascending branch of the Sylvian fissure (SF), which originates at the point of bifurcation (•) and terminates at S. PC sub 1 is the inferior end of PC at SF. The tracing of the superimposed hemispheres (3) shows the asymmetry in position and size between the parietal opercula. The tracings of Einstein's hemispheres (6) highlights the confluence of PC and the posterior ascending branch of SF in each hemisphere, the absence of the parietal opercula, and the symmetry of the sulcal morphology between hemispheres. Comparison of the tracings shows the relatively anterior position of the SF bifurcation in Einstein, and the associated greater posterior parietal expanse, particularly in his left hemisphere compared with the control brain.

A further consequence of this morphology is that the full supramarginal gyrus lies behind the Sylvian fissure, undivided by a major sulcus as is usually the case.
Einstein's brain weight was not different from that of controls, clearly indicating that a large (heavy) brain is not a necessary condition for exceptional intellect.

This report clearly does not resolve the long-standing issue of neuroanatomical substrate of intelligence. However, the findings do suggest that variation in specific cognitive functions may be associated with the structure of the brain regions mediating those functions. The results have heuristic value for developing hypotheses of the gross and microscopic anatomical substrate of differing aspects of intelligence that can be tested in future neuroimaging and post-mortem studies. In particular, the results predict that anatomical features of parietal cortex may be related to visuospatial intelligence.

Correspondence Information

Dr. Sandra F. Witelson (witelson@mcmaster.ca)
Department of Psychiatry and Behavioral Neuroscience

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