Having a bigger brain does NOT mean you have a better memory because having a lot of white matter is just as important, study finds
- Researchers scanned brains of 330 adults and got them to take memory tests
- Found those with big hippocampus (memory centre) were not necessarily better
- Only those with more white matter joining it to rest of brain had better recall
Having a bigger brain does not mean you have a better memory, according to scientists.
Researchers scanned the brains of more than 330 adults and got them to take learning and memory tests.
They found that those with a larger hippocampus, a section of the brain which serves as the memory centre, did not necessarily perform better on the tests.
Past research has shown that the hippocampus shrinks with age and may be linked to memory loss in pensioners and people with Alzheimer’s disease.
But this study found that, more specifically, it was the quantity of a specific type of white matter – called limbic white matter – which dictated how good someone’s memory was.
This was demonstrated by people with larger hippocampuses but less intact white matter having worse memories than those with the opposite.
A larger brain does give you better steed in tasks using memory, logic and reactions, scientists from the US and Netherlands have confirmed using data from 13,600 Britons (stock image)
A 2004 study showed that the size of the hippocampus is not always related to memory performance in older adults.
But this is the first study to shed light on why, the researchers said.
Michigan State University’s Dr Andrew Bender, who authored the new study, said the findings showed the need to look at the connection between the hippocampus and the rest of the brain when looking at memory decline in older adults.
He and his colleagues, who included researchers from Hungary and Germany, looked at different types of MRI scans on the brains of participants.
One scan was to reveal the size of the hippocampus, while the second examined white matter.
WHAT IS THE HIPPOCAMPUS?
The hippocampus is a major part of the brains of humans and other vertebrates.
It is named after its resemblance to a seahorse, with hippos meaning horse in Greek.
It is located in the temporal lobe of the brain and contains two interlocking parts, called hippocampi.
Humans have known about the hippocampus for more than four centuries, making it one of the most studied parts of the brain.
Its main functions involve human learning and memory. It has even helped researchers learn how memory works.
Rodents use the brain region for navigating and recognising their environment.
In Alzheimer’s disease, the hippocampus is one of the first regions of the brain to be damaged, leading to memory loss and disorientation.
Researchers were able to shed light on its role in memory function following the treatment of a young man, Henry Molaison for epilepsy in the 1950s.
He had brain surgery to remove the part of his brain where his epileptic seizures seemed to be coming from. This included both of his hippocampi.
He recovered from the surgery and his epilepsy was under control.
But he had very serious memory problems. He could recall memories from his early childhood, but he could not remember much from the years leading up to his surgery.
More importantly, he had lost the ability to create new memories.
Similar problems develop when the hippocampus is damaged by illnesses such as Alzheimer’s disease, or hurt in an accident.
White matter is flesh in the centre of the brain which is crammed full with nerves relaying messages all over the organ in the form of electrical signals.
It differs from grey matter which is composed of other types of cells such as blood vessels and ones which transport nutrients into the brain tissue.
People in the study then did brainpower test, one of which included them needing to listen to 15 words and write down as many as they could remember afterwards.
They re-did the test five times so the scientists could see how good they were at learning through repetition.
Dr Bender and his colleagues then tried to find a link between how quickly people learned the words and the size of their hippocampus and white matter.
They found that only those with both a larger hippocampus and also more white matter circuits connecting it to the rest of the brain learned faster than the others.
Dr Bender added: ‘Our findings reinforce a growing perspective that studying age-related changes in learning and memory from a systems perspective appears far more informative in understanding different patterns of brain and cognitive declines than focusing on any single brain region.’
Next, the research team want to use more data from the same people to see if they can see a change in their brain structures which is linked to learning or memory declines.
The findings could help doctors make more accurate early diagnoses of age-related conditions such as Alzheimer’s.
Alzheimer’s, the most common form of dementia, is a progressive disease which destroys memory and thinking skills and ultimately the ability to carry out even simple tasks.
The condition affects around 500,000 people in the UK, with more than 850,000 suffering from dementia more generally.
There are around 5.7million dementia sufferers in the US, with 4million of them suffering from Alzheimer’s.
The research was published in the medical journal Cerebral Cortex.
WHAT IS DEMENTIA? THE KILLER DISEASE THAT ROBS SUFFERERS OF THEIR MEMORIES
Dementia is an umbrella term used to describe a range of neurological disorders
A GLOBAL CONCERN
Dementia is an umbrella term used to describe a range of progressive neurological disorders (those affecting the brain) which impact memory, thinking and behaviour.
There are many different types of dementia, of which Alzheimer’s disease is the most common.
Some people may have a combination of types of dementia.
Regardless of which type is diagnosed, each person will experience their dementia in their own unique way.
Dementia is a global concern but it is most often seen in wealthier countries, where people are likely to live into very old age.
HOW MANY PEOPLE ARE AFFECTED?
The Alzheimer’s Society reports there are more than 850,000 people living with dementia in the UK today, of which more than 500,000 have Alzheimer’s.
It is estimated that the number of people living with dementia in the UK by 2025 will rise to over 1 million.
In the US, it’s estimated there are 5.5 million Alzheimer’s sufferers. A similar percentage rise is expected in the coming years.
As a person’s age increases, so does the risk of them developing dementia.
Rates of diagnosis are improving but many people with dementia are thought to still be undiagnosed.
IS THERE A CURE?
Currently there is no cure for dementia.
But new drugs can slow down its progression and the earlier it is spotted the more effective treatments are.
Source: Alzheimer’s Society