New brain study shows what makes us intelligent (Hint: The answers are behind your forehead and your left ear)



The mystery of what makes us intelligent has been uncovered by US researchers.

A groundbreaking new map of the brain reveals reveals exactly where in the brain we listen, comprehend and remember, and how those areas work together to give us intelligence.

Scientists say the research could lead to major new understandings of how the human brain works.

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Color-coded: In this map of the brain, red shows common areas, orange shows regions specific to general intelligence and yellow shows areas specific to executive function

Researchers were able to study a unique group of patients -- 182 Vietnam veterans with highly localised brain damage from penetrating head injuries.

The researchers say because the participants had similar injuries, it made them the perfect candidates.

'It's a significant challenge to find patients for research who have brain damage,' said University of Illinois neuroscience professor Aron Barbey, who led the study.

The brain injuries studied allowed researchers to pinpoint which parts of the brain were being used.

'By studying how damage to particular brain regions produces specific forms of cognitive impairment, we can map the architecture of the mind, identifying brain structures that are critically important for specific intellectual abilities,' said Professor Barbery.

Damaged: The study relied on using brains with localized specific injuries, one of them seen here, to determine which parts of the brain worked for intelligent thought

The researchers took CT scans of the participants' brains and gave them a series of tests. They then combined the resulting scans to produce a collective map, which they divided into more than 3,000 three-dimensional pieces called voxels.

By analysing multiple patients with damage to a particular voxel or cluster of voxels and comparing their cognitive abilities with those of healthy patients, the researchers were able to identify brain regions essential to specific cognitive functions, and those structures that contribute significantly to intelligence.

'Several brain regions, and the connections between them, were most important for general intelligence,' Professor Barbary said.

Areas in blue and green appear to be vital to general intelligence, areas in yellow and green indicate brain regions vital to performance on the specific cognitive tasks

The team found the key areas of the brain for intelligence were the left prefrontal cortex (behind the forehead), left temporal cortex (behind the ear) and left parietal cortex (at the top rear of the head) and in the areas that connect them.

The researchers also found that brain regions for planning and self-control overlap to a significant extent with regions vital to general intelligence.

They say the study provides new evidence that intelligence relies not on one brain region or even the brain as a whole, Professor Barbey said, but involves specific brain areas working together in a coordinated fashion.

'In fact, the particular regions and connections we found support an emerging body of neuroscience evidence indicating that intelligence depends on the brain's ability to integrate information from verbal, visual, spatial and executive processes,' he said.