Joined-up thinking makes you smarter

Brains with nerve connections in better condition make older people think faster and smarter, new research has found.

Researchers from the University of Edinburgh have found that older people with more intact brain ‘wiring' - that is, the nerve fibres that connect different, distant brain areas - can process information faster 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.

However a loss of integrity 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. The research shows for the first time 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 and indicate structural loss in the brain and how well the nerve fibres are insulated.

The researchers examined scans and the results of thinking and reaction time tests from 420 people in the Lothian Birth Cohort of 1936.  The results were part of the Disconnected Mind Project, a large study of the causes of people's differences in cognitive ageing, led by Professor Ian Deary and mainly funded by Age UK.

Professor Deary said that uncovering the secrets of good thinking skills in older age is a high priority.  "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."

Age Scotland spokesman Lindsay Scott said: "This research is exciting as it could have a real impact on tackling mental decline, including dementia, in later life. With new understanding on how the brain functions, we can work out why mental faculties decline with age in some people and not others and look at what can be done to improve our minds' chances of ageing better."

The research has been published in the journal Molecular Psychiatry.