Brains that maintain healthy nerve connections as we age help keep us sharp in later life.
An Age UK-funded project at the University has found that older people with robust brain wiring - that is, the nerve fibres that connect different, distant brain areas - can process information quickly and that this makes them generally smarter.
According to the findings, joining distant parts of the brain together with better wiring improves mental performance, suggesting that intelligence is not found in a single part of the brain.
Our results suggest a first plausible way how brain structure differences lead to higher intelligence. The results are exciting for our understanding of human intelligence differences at all ages.
A loss of condition of this wiring or white matter - the billions of nerve fibres that transmit signals around the brain - can negatively affect our intelligence by altering these networks and slowing down our processing speed.
This is the first time it has been shown that the deterioration of white matter with age is likely to be a significant cause of age-related cognitive decline.
The research team used three different brain imaging techniques in compiling the results, including two that have never been used before in the study of intelligence.
These techniques measure the amount of water in brain tissue, indicate structural loss in the brain, and show how well the nerve fibres are insulated.
The research team is now looking at what keeps the brain’s connections healthy. We value our thinking skills, and research should address how we might retain them or slow their decline with age.
Researchers examined scans and results of thinking and reaction time tests from 420 people in the Lothian Birth Cohort of 1936.
This is a group of nearly 1100 people whose intelligence and general health have been tracked since they were 11 years old.
The research was part of the Disconnected Mind Project, a large study of the causes of people’s differences in cognitive ageing, led by Professor Ian Deary.
It was published in the journal Molecular Psychiatry.
The results suggest a clear target for seeking treatment for mental difficulties, be they pathological or age-related. That the brain’s nerve connections tend to stay the same throughout the brain means we can now look at factors that affect the overall condition of the brain, like its bloody supply.