It's been known for quite some time that the overall size of the brain of an individual can be used to judge how intelligent he or she is. More specifically, it's been discovered that the size of the brain itself accounts for about 6.7 percent of individual variation in intelligence.
More recent research has pinpointed the brain's lateral prefrontal cortex, a region just behind the temple, as a critical hub for high-level mental processing, with activity levels there predicting another 5 percent of variation in individual intelligence.
Now, new research from Washington University in St. Louis suggests that another 10 percent of individual differences in intelligence can be explained by the strength of the neural pathways connecting the left lateral prefrontal cortex to the rest of the brain.
Washington University's Dr. Michael W. Cole -- a postdoctoral research fellow in cognitive neuroscience -- conducted the research that provides compelling evidence that those neural connections make a unique contribution to the cognitive processing underlying human intelligence.
The discovery was made after the Washington University researchers analyzed functional magnetic resonance brain images captured as study participants rested passively and also when they were engaged in a series of mentally challenging tasks, such as indicating whether a currently displayed image was the same as one displayed three images ago.
One possible explanation of the findings is that the lateral prefrontal region is a "flexible hub" that uses its extensive brain-wide connectivity to monitor and influence other brain regions. While other regions of the brain make their own special contribution to cognitive processing, it is the lateral prefrontal cortex that helps co-ordinate these processes and maintain focus on tasks at hand, in much the same way that the conductor of a symphony monitors and tweaks the real-time performance of an orchestra.
Now this discovery, of course, could have some important implications. Imagine for, example, a future where employers insisted that all their prospective employees underwent such a scan as part of their interviewing process so that they could ensure that they always hired folks with lots of gray matter.
That thought might worry you, but not me. You see, my old man was always telling me that I had a big head. Then again, maybe he never meant his remarks to be taken as a complement.
Interested in reading more about the uses of magnetic resonance imaging in medical applications? Here's a compendium of five top news stories on the subject that Vision Systems Design has published over the past year.
1. MRI maps the development of the brain
Working in collaboration with colleagues in South Korea, scientists at Nottingham University (Nottingham, UK) aim to create a detailed picture of how the Asian brain develops, taking into account the differences and variations which occur from person to person.
2. Ultraviolet camera images the brain
Researchers at Cedars-Sinai Medical Center (Los Angeles, CA, USA) and the Maxine Dunitz Neurosurgical Institute are investigating whether an ultraviolet camera on loan from NASA's Jet Propulsion Laboratory could help surgeons perform brain surgery more effectively.
3. Imaging technique detects brain cancer
University of Oxford (Oxford, UK) researchers have developed a contrast agent that recognizes and sticks to a molecule called VCAM-1 that is present in large amounts on blood vessels associated with cancer that has spread to the brain from other parts of the body.
4. Imaging the brain predicts the pain
Researchers from the Stanford University School of Medicine (Stanford, CA, USA) have developed a computer-based system that can interpret functional magnetic resonance (fMRI) images of the brain to predict thermal pain.
5. Camera takes a closer look at the workings of the brain
Optical imaging of blood flow or oxygenation changes is useful for monitoring cortical activity in healthy subjects and individuals with epilepsy or those who have suffered a stroke.