Different parts of the brain age at different rates

by Madlen Davies for The Daily Mail:

Different parts of the brain age at different rates, scientists have discovered.

The research explains why older people will lose some functions of the brain more quickly than others.

For example, they may lose the ability to pay a bill more quickly than the ability to multi-task, scientists said.

This is because the part of the brain responsible for problem-solving – which allows us to understand a bill, plan a shopping trip or make a decision – deteriorates faster than parts of the brain responsible for multi-tasking.

And people will lose these abilities at different times, as some parts of individuals' brains will age at different rates to others', scientists found.

This challenges the previously held idea that, as we get older, these types of mental abilities all decline at the same rate.

Scientists say the research is especially important given that people are living longer in industrialised countries, leading to ageing populations.

Skills such as understanding a new utilities bill or planning a shopping trip depend on relatively high-level cognitive abilities, called 'executive functions'.

As we grow older, our ability to perform executive functions declines more swiftly than the skills required to perform more simple or repetitive tasks, like making a cup of tea or taking a familiar route to the shops.

Executive functions are associated with the frontal lobe of the brain, especially the prefrontal cortex.

This area is known to deteriorate quite rapidly as we get old.

Previously, scientists thought that all executive functions declined at the same rate as this part of the brain degenerated.

But the new research shows that this view is far too simplistic: different parts of the prefrontal lobe deteriorate at different rates.

Scientists from the Medical Research Council’s Cognition and Brain Sciences Unit analysed the data from different cognitive tests of 600 people and measured different types of brain tissue in specific parts of the brain.

All the individuals were aged between 18 and 88.

They found two distinct skills associated with specific areas of the brain.

The first was multi-tasking, the ability to perform more than one task simultaneously.

The second was fluid intelligence - or the ability to problem solve - which is measured in typical IQ tests.

Problem-solving abilities allow people to think logically, make decisions and carry out tasks using logic rather than a trial and error approach.

Scientists found these abilities deteriorated at different rates in different people.

The ability to problem-solve more likely to be affected by age, whereas the ability to multi-task was more likely to be preserved.

The loss of some abilities but not others suggests people's brains were ageing differently.

Deterioration of the prefrontal cortex, the area of the brain which is responsible for problem-solving and multi-tasking, can be measure in many ways.

One way is to look in terms of the loss of the grey matter of the brain, which contains brain's cell bodies and does most of the information processing, and the white matter, which contains the pathways that allow cells in different parts of the brain to communicate.

It's also possible to study deterioration within the sub-regions of the pre-frontal lobe.

The scientists found different parts of the pre-frontal lobe of the brain, and different tissues (both white and grey matter) played specific and complementary roles in supporting either problem solving or multi-tasking.

Researchers discovered they aged at different rates, with white matter connections more likely to be affected by age.

Dr Rogier Kievit, of Cambridge University, said: 'These results demonstrate that ageing, even for cognitive abilities that seem similar, is a far more multifaceted process than commonly thought.

'It's crucial that we understand the role that different types of brain tissue play in cognition, especially in ageing brains, as we know from other research that lifestyle factors – such as exercise – can have different effects on white and grey matter.

'Knowing more about the neurological basis of age-related differences in people's mental abilities might help us identify what factors are most likely to contribute to greater independence and a better quality of life for older people.'

The research was published in the journal Nature Connections.

Source: http://dailym.ai/1x2Hdaw