Recent research conducted by Paul Thompson and colleagues at the University of California has indicated that intelligence levels, directly associated with IQ, are partially genetically determined. Adding to the previous discoveries of heritable cells in the both the grey matter 'processor cells' and white matter 'connections between processor cells', the quality of these connections has now also been found to be heritable.
The research involved scanning the brains of identical twins and fraternal twins, in order to compare the amount of water that is able to diffuse through the protective myelin sheath enveloping the white matter, resulting in a measure of nerve impulse speed. Using these scans, the team was able to deduce that the 'integrity' of the myelin sheath was genetically determined in parts of the brain responsible for intelligence. Richard Haier, also from the University of California, has noted that although the basis for intelligence is at least partly genetic, it can still be improved, as the myelin sheath can change throughout the duration of its life.
This study suggests that both genetic and environmental factors can influence the integrity of the myelin sheath, perhaps leading into medical/scientific manipulations of this genetic material responsible for multiple sclerosis, autism and attention deficit disorder.
Referenced from: "High Speed Brains are in the Genes" - Aria Pearson. New Scientist, issue 2699. 11/03/2009
http://www.newscientist.com.ezproxy.library.uq.edu.au/article/mg20126993.300-highspeed-brains-are-in-the-genes.html
Kate Carnell
