Category: Dementia

Men and women use different strategies to navigate — but which is really most effective?

Men have a better sense of direction than women, a new study finds.

But putting some testosterone under women’s tongues improves their performance.

This suggests that men’s advantage at navigation is more than a stereotype or cultural belief, but has some biological basis.

The research had men and women trying to find their way around a maze in virtual reality.

Dr Carl Pintzka, who led the study, explained the main result:

“Men’s sense of direction was more effective.

They quite simply got to their destination faster.”

Men solved 50% more of the navigational tasks than women.

The reason is partly because men and women use different strategies.

Men tend to use cardinal directions more: north, east, south and west.

Women, though, tend to work out a route.

Dr Pintzka explained:

“If they’re going to the Student Society building in Trondheim, for example, men usually go in the general direction where it’s located.

Women usually orient themselves along a route to get there, for example, ‘go past the hairdresser and then up the street and turn right after the store’,”

It turns out that going in the general direction is a better strategy because it is more flexible.

On the other hand, following a known route obviously depends on where you start — so it’s not as flexible.

The scientists also scanned men’s and women’s brains to look for differences.

The scans revealed that men tended to use their hippocampus more for navigation, while women relied on their frontal lobes.

Dr Pintzka said:

“…other researchers have documented that women are better at finding objects locally than men.

In simple terms, women are faster at finding things in the house, and men are faster at finding the house.”

In a second stage of the study, some women were given testosterone to try and boost their performance.

This did help women’s navigational performance, but not much, Dr Pintzka said:

“We hoped that they would be able to solve more tasks, but they didn’t.

But they had improved knowledge of the layout of the maze.

And they used the hippocampus to a greater extent, which tends to be used more by men for navigating.”

Sense of direction could provide a clue as to how to treat some brain diseases, Dr Pintzka said:

“Almost all brain-related diseases are different in men and women, either in the number of affected individuals or in severity.

Therefore, something is likely protecting or harming people of one sex.

Since we know that twice as many women as men are diagnosed with Alzheimer’s disease, there might be something related to sex hormones that is harmful.”

The study was published in the journal Behaviour Brain Research (Pintzka et al., 2015).

Directions image from Shutterstock

Ordinarily, older brains have to work harder to do the same job as younger brains.

The link between physical fitness, better brain function and brain activation has been shown for the first time.

Research on older Japanese men has shown that the brains of those who are fitter perform like those of much younger men.

The finding is based on how typical patterns of brain activation change with age.

The images below show the difference between young and old in brain activation on a typical memory test.

As you can see, younger adults primarily use the left side of the prefrontal cortex for the short-term memory task.

Older adults, meanwhile, tend to use the left and right side of the brain equally for the same task.

The reason is that with age the brain typically doesn’t work so well, so we need to utilise more of it to do the same task

Neuroscientists have a nick-name for this change: HAROLD.

It stands for “hemispheric asymmetry reduction in older adults”.

In the study, though, neuroscientists found that older men who were fitter tended to use the left-side of their brains more, just like younger people.

On top of that, fitter seniors also had faster reaction times.

Professor Hideaki Soya, who led the study, said:

“…one possible explanation suggested by the research is that the volume and integrity of the white matter in the part of brain that links the two sides declines with age.

There is some evidence to support the theory that fitter adults are able to better maintain this white matter than less fit adults, but further study is needed to confirm this theory.”

We don’t yet know if the results would be the same for women, but it would be surprising if they weren’t.

The study was published in the journal Neuroimage (Hyodo et al., 2015).

Shiny brain image from Shutterstock

Contrary to popular belief, this supplement doesn’t prevent cognitive decline.

In one of the largest and longest studies to date, no evidence was found that omega-3 can protect against cognitive decline.

However, the supplement is likely to be beneficial in many other ways, including for eye health.

Dr Emily Chew, who led the study, said:

“Contrary to popular belief, we didn’t see any benefit of omega-3 supplements for stopping cognitive decline.”

The study was originally designed to look at the potential benefits of taking nutritional supplements on the eyes.

The findings for this were positive, Dr Chew explained:

“We’ve seen data that eating foods with omega-3 may have a benefit for eye, brain, and heart health.”

But the researchers found that omega-3 had no beneficial effects on cognitive decline.

Cognitive decline is particularly important as it has been linked to Alzheimer’s disease.

For the study, scientists followed 4,000 seniors over five years.

Despite the results, Dr Lenore Launer, a study author, does not rule out the possibility that omega-3 might still be beneficial for brain health:

“It may be, for example, that the timing of nutrients, or consuming them in a certain dietary pattern, has an impact.

More research would be needed to see if dietary patterns or taking the supplements earlier in the development of diseases like Alzheimer’s would make a difference.”

The research was published in JAMA (Chew et al., 2015).

Brain aging image from Shutterstock

Test identifies smaller brain volume and problems with thinking.

A simple saliva test could help identify thinking problems in older people, a new study finds.

The study found a connection between the stress hormone cortisol and thinking skills.

Higher cortisol levels in the evening were linked to worse thinking skills and smaller brain volumes.

Dr Lenore J. Launer, one of the study’s authors, said:

“Studies have shown that depression increases the risk for dementia, but we don’t know much about how this relationship occurs.

High levels of the stress hormone cortisol have been found in people with depression, and the theory is that cortisol has a toxic effect on the hippocampus area of the brain, which plays an important role in memory.”

The study included data from 4,244 people who did not have dementia.

Dr Launer said:

“Since this study just looked at a snapshot in time, we don’t know which came first: the high levels of cortisol or the loss of brain volume.

It’s possible that the loss of brain volume that can occur with aging leads to a lesser ability of the brain to stop the effects of cortisol, which in turn leads to further loss of brain cells.

Understanding these relationships may help us develop strategies to reduce the effects of cortisol on the brain and thinking skills.”

The research was published in the journal Neurology (Mirjam et al., 2015).

Thinking image from Shutterstock

Given the power of modern medicine, why have brain diseases increased by four times?

Rates of brain diseases are increasing at almost epidemic rates, especially in the US, a new study reports.

Researchers have compared figures for neurological disease from 1989 with those from 2010 across 21 Western countries.

They found that dementia is starting, on average, a decade earlier in 2010 than it was in 1989.

In the US, the figures are particularly worrying.

Women over 75 are suffering five times as many neurological deaths as they were two decades ago.

The same comparison for men over 75 shows a three-fold increase in neurological deaths.

Professor Colin Pritchard, who led the study, said:

“The rate of increase in such a short time suggests a silent or even a ‘hidden’ epidemic, in which environmental factors must play a major part, not just aging.

Modern living produces multi-interactional environmental pollution but the changes in human morbidity, including neurological disease is remarkable and points to environmental influences.”

Professor Pritchard continued:

“In part, some of the results are explained by more effective treatments for cancer and heart disease, with advances in medicine making such physical illnesses easier to treat, whilst there have been less advances in the treatment of neurological conditions.

Crucially it is not just because people are living longer to get diseases they previously would not have lived long enough to develop but older people are developing neurological disease more than ever before.

The environmental changes in the last 20 years have seen increases in the human environment of petro-chemicals — air transport- quadrupling of motor vehicles, insecticides and rises in background electro-magnetic-field, and so on.

These results will not be welcome news as there are many with short-term vested interests that will want to ignore them.

It is not that we want to stop the modern world but rather make it safer.

Essentially, it is time for us to wake up and realize that a major problem we now face is unprecedented levels of neurological disease, not just the earlier dementias and thinking of the USA — `when America sneezes, Europe gets cold a decade later.”

The study was published in the journal Surgical Neurology International (Pritchard & Rosenorn-Lanng, 2015).

Brain image from Shutterstock

Vessels discovered in the brain that were thought not to exist — could revolutionise study of neurological diseases like Alzheimer’s.

The brain is directly connected to the immune system by vessels previously thought not to exist, new research reports.

The finding means the textbooks will have to be rewritten.

Discovery of the vessels may also revolutionise the study of neurological diseases like Alzheimer’s and autism.

Professor Jonathan Kipnis, who led the research, was initially sceptical about the results:

“I really did not believe there are structures in the body that we are not aware of.

I thought the body was mapped.

I thought that these discoveries ended somewhere around the middle of the last century.

But apparently they have not.”

The vessels are located in the meninges — the membrane that surrounds the brain and spinal cord.

The vessels run near major blood vessels, which partly explains why they have been so difficult to find.

The left-hand image below shows the old map of the lymphatic system and the updated version is on the right.

The discovery will likely have profound implications for how scientists study the neuro-immune system, Professor Kipnis said:

“Instead of asking, ‘How do we study the immune response of the brain?’ ‘Why do multiple sclerosis patients have the immune attacks?’ now we can approach this mechanistically.

Because the brain is like every other tissue connected to the peripheral immune system through meningeal lymphatic vessels.

It changes entirely the way we perceive the neuro-immune interaction.

We always perceived it before as something esoteric that can’t be studied.

But now we can ask mechanistic questions.

We believe that for every neurological disease that has an immune component to it, these vessels may play a major role.

Hard to imagine that these vessels would not be involved in a [neurological] disease with an immune component.

In Alzheimer’s, there are accumulations of big protein chunks in the brain.

We think they may be accumulating in the brain because they’re not being efficiently removed by these vessels.”

The study was published in the journal Nature (Louveau et al., 2015).

Network brain image from Shutterstock and lympatic system image from University of Virginia Health System

How coffee intake affects the chance of developing mild cognitive impairment.

Drinking one or two cups of coffee a day can protect the brain against a precursor to dementia, a new study finds.

More coffee, though, does not lead to a higher neuro-protective effect.

In fact, the study found that people who increased their consumption by a cup or two had twice the risk of mild cognitive impairment (MCI).

MCI is a common precursor to developing forms of dementia, like Alzheimer’s disease.

Symptoms of MCI include minor memory problems and slowed thinking and judgement.

The Italian study of 1,445 people also found that people not drinking coffee were at higher risk than those who drank moderate amounts.

The study’s authors write:

“These findings from the Italian Longitudinal Study on Aging suggested that cognitively normal older individuals who never or rarely consumed coffee and those who increased their coffee consumption habits had a higher risk of developing MCI.

Therefore, moderate and regular coffee consumption may have neuroprotective effects also against MCI confirming previous studies on the long-term protective effects of coffee, tea, or caffeine consumption and plasma levels of caffeine against cognitive decline and dementia,”

Participants in the study were aged 65 to 84-years-old.

They were followed up over an average of 3.5 years to see if they had developed any thinking problems.

The study was published in the Journal of Alzheimer’s Disease (Solfrizzi et al., 2015).

Image credit: Eric