Mercury in the Human Brain

A recently developed technique of neutron activation analysis permitted a sensitive analysis of mercury in over 160 samples of fresh brain tissue from 17 randomly selected autopsies. There was a preferential deposition of mercury in various anatomical loci. Many of these loci are those clinically or histologically affected in poisoning by methyl mercury. The greatest concentration of the metal was generally present in the cerebellum with a mean of 0.28 μMg/g (parts per million). Forty per cent of the cerebellums had concentrations greater than 0.2 ppm. The visual cortex, pons and geniculate bodies contained levels averaging 0.17 to 0.20 ppm. The lowest levels were found in the frontal lobe white matter (mean 0.07 ppm). Two brains from patients with no exceptional exposure to environmental mercury had unusually elevated levels of 1 to 2 ppm in many regions.