It has always been thought that the intelligence of a person was at least partially heredity, however it has never been known just HOW much a person's intelligence is linked to genes. A recent investigation conducted by the University of California has determined that the quality of connections between different parts of the brain is much more heritable then previously thought.
An experiment was conducted using 23 sets of identical twins and the same number of fraternal twins, HARDI scans were used to determine the integrity of myelin sheathing and the speed of each nerve pulse - these are both direct links to measuring a person's "mental speed". It was shown by comparing the scans of fraternal and identical twins that myelin quality is linked to IQ scores and overall intelligence. Furthermore, the link between the left and right side of the brain is also largely genetic.
It is surprising to learn however that a person's intelligence can be improved regardless as to how directly it is linked to genes. Myelin changes throughout a person's lifetime this may be due to the fact that the quality of myelin changes to interact with our environment.
Scientists are now hoping that they will be able to determine ways of improving the genes responsible for the quality of myelin in the body which in turn could potentially help find therapies for those people suffering from disorders such as ADHD or autism which are due to low-quality myelin in the brain. Scientists have also hypothesised that boosting a person's intelligence level before an exam could potentially be possible - however it's important to not get our hopes up yet as this is a long way off. Scientists have to determine a way to untangle links between the environment and the levels of myelin.
There's an interactive graphic as to how directly linked to genes each fibre quality of different parts of the brain are: http://www.newscientist.com/movie/mg20126993300-genetic-link-to-iq-stronger-than-thought
If you can't access it though, here are the statistics:-
* Parietal Lobe (Responsible for Visuospatial skills, mathematics, logic) - 85%
* Corpus Callosum (Integrating signals from left to right side of the brain) - 100% [Except in language areas]
* Frontal Lobe (Planning, inhibition, self-control) - 65%
* Temporal Lobe (Learning and memory) - 45%
* Visual Cortex (Vision) - 76%
REFERENCES:
http://www.newscientist.com/article/mg20126993.300-highspeed-brains-are-in-the-genes.html
http://www.jneurosci.org/cgi/content/abstract/29/7/2212
IMAGE: David Shattuck / Arthur Toga / Paul Thompson / UCLA
It is of a HARDI scan.
Chelsea Geary 41767173
