Major and trace element concentration differences between the right and left hemispheres of the "normal' human brain.

The brain can be divided into many anatomical regions, and the minor and trace element distribution across these regions has been shown to be heterogeneous. The various functions of the brain such as memory and language have been associated with different brain regions, and attempts to correlate brain function with elemental composition have been made. Establishing "normal" concentration values is a complex task due to the variability of factors such as age, sex, dietary intake, environmental exposure, and smoking habits. In establishing the elemental concentration of a particular brain region, a mean value from the right and left hemispheres of different brains is often used. This is usually due to the lack of availability for analysis of the same brain regions from both hemispheres of one individual. However, it is known that the right and left hemispheres have different functions. Thus, it may be expected that they may have different trace element concentrations as well. In this study 13 brain regions were sampled from both hemispheres of six elderly individuals, and their major element composition was determined by Rutherford backscattering (RBS) analysis, whereas the minor and trace element concentrations were obtained by particle induced X-ray emission (PIXE) analysis.