Saturday, January 27, 2018

The modern human brain may be younger than previously thought: Study reveals it took shape as recently as 40,000 years ago as we learned to build tools and socialize

The earliest-known Homo sapiens specimen traces back to 300,000 years ago
But the modern human brain's rounded shape may be only 35,000 years old
Scientists say our brains evolved from an elongated form to a globular shape to compensate for more complex processes, like tool building and self-awareness

The earliest-known specimen of a Homo sapiens dates back to roughly 300,000 years ago.

Though much has changed since then, scientists long believed that our species still retained one common feature - our brains.

It turns out that our brains actually look much different from our ancestors that lived hundreds of thousands of years ago.

Now a team of scientists have discovered, for the first time ever, exactly when our brains began to take on their unique, modern shape.

A team of researchers from the Max Planck Institute for Evolutionary Anthropology in Germany pinpointed the period when the human brain achieved its current form as being between 100,000 and 35,000 years ago.

New research from a team of scientists in Germany pinpoints the exact period when our brains achieved their modern shape. Pictured, a Neanderthal brain (left) appears more elongated than the present-day Homo sapiens (right) brain, which is 'rounder and less overhanging'

By contrast, Neanderthals and 'other archaic Homo individuals' possessed elongated brains.

Neanderthals are our species' closest relative, going extinct tens of thousands of years ago.

Over time, the frontal area of our brains became taller and the parietal areas began to bulge, while the side walls became parallel.

Present-day skulls have a globe-like shape, with a smaller and more delicate facial structure.

Most importantly, the occipital area -- which is located in the back of the head and processes visual information -- 'becomes rounder and less overhanging,' according to the study.

'The brain is arguably the most important organ for the abilities that make us human,' says Simon Neubauer, a co-author of the study.

'We already knew that brain shape must have evolved within our own species, but we were surprised to discover just how recent these changes to brain organization were.'

Two features predominantly contribute to the brain's globular appearance: The bulging of the brain's parietal area and the cerebellum.

Researchers estimate that roughly 100,000 to 35,000 years ago, our brains evolved from an elongated shape to a globe-like shape. The evolution in brain shape coincided with the introduction of new processes like tool building, self-awareness and long-term memory

These areas serve as an 'important hub' of brain organization, responsible for functions like motor control, balance, memory, language, social cognition and the ability to process things around us.

This suggests that evolutionary changes to our brain were key to the evolution of the human condition, the scientists said.

'The evolution of endocranial shape within Homo sapiens suggests evolutionary changes of early brain development -- a critical period for neural wiring and cognitive development,' said Philipp Gunz, a co-author of the study.

The scientists point out that these evolutionary changes were gradual, taking place over tens of thousands of years.

HOW HAS THE SHAPE OF OUR BRAINS EVOLVED OVER TIME?

New research suggests key evolutionary changes in our brain shape occurred 100,000-35,000 years ago. Stock image

Researchers at Germany's Max Planck Institute for Evolutionary Anthropology discovered that key evolutionary changes in our brain shape occurred roughly 100,000 to 35,000 years ago

The Homo sapiens brain took on a globe-like shape that's 'rounder and less overhanging'

By contrast, our Neanderthal ancestors' brains had a more elongated shape

The evolution of our brain shape coincided with major developments in behavior, as Homo sapiens began to:

Build tools

Develop a working and long-term memory

Possess self-awareness

Use language

Plan activities

Understand numbers

Pay attention to their surroundings

Develop emotions

The brain began to look more like a globe as a result of bulging in the parietal area and the cerebellum Using CT scans, the scientists examined changes in the brain's curvature, surface size and other details to chart gradual changes in its shape.

From that, they determined that our brains reached their present-day variation between 100,000 and 35,000 years ago.

Neubauer told Business Insider that the globular brain shape isn't what caused us to develop those new brain functions.

Instead, Neubauer said the rounder shape is 'related to our modern behavior.'

This latest study follows research from the same team of scientists, published last year, where they discovered that the earliest-known Homo sapiens specimen were 100,000 years older than previously thought.

The oldest fossils date back to 300,000 years ago and were located in Jebel Irhoud, Morocco.

Scans revealed that the bones have similar structure to modern humans.

Wednesday, January 24, 2018

WHEN YOU AGE

What REALLY happens when you age? Expert debunks five popular myths about sex and brain power

Dana Rosenfeld is a reader in sociology based at Keele University, Staffordshire
She says it's unsurprising that much of what we 'know' about ageing is untrue
Over 65s make up a larger percentage of the global population than ever before

People over the age of 65 make up a larger percentage of the global population than ever before.

As this ageing of society only really took off in the last century, it's unsurprising that much of what we think we know about ageing is untrue.

The 'facts' about ageing depict people as becoming somehow less – less capable, less vibrant, less flexible, less sexual and less fulfilled.

But how many of these 'facts' hold up to scrutiny?

Here, in a piece for The Conversation, Dr Dana Rosenfeld, a reader in sociology based at Keele University, investigates five common beliefs.

As this ageing of society only really took off in the last century, it's unsurprising that much of what we think we know about ageing is untrue

Libido and sexual activity decrease

This is not true. Hormone levels change as we age, but this doesn't necessarily decrease libido. Indeed, for women, libido often increases after the menopause.

Older people's libido may be lowered by chronic illness (such as diabetes and heart disease), drug side effects (antihypertensive drugs, for example) and marital unhappiness and boredom.

So decreases in sexual desire in old age are often due to events and circumstances, not to physical changes that come with age.

Having a sexual partner, however, is the strongest factor for determining how often older people have sex.

Because women tend to marry older men, who die younger, older women's reduced sexual activity is largely due to widowhood.

WILL OLDER PEOPLE ENDURE A LIFETIME OF MULTI-ILLNESSES?

People in their 60s are set to suffer at least four diseases by the time they reach their 80s, Newcastle University research has revealed.

By 2035 men are expected to live 3.6 years and women 2.9 years longer than they do now, the researchers predicted on the back of a review of trials.

However, two-thirds of this extra time will be spent suffering from multiple illnesses, according to the study published in the journal Age and Ageing in January 2018.

This forecast is blamed on rising rates of obesity and falling activity levels making people less healthy.

The researchers discovered in 2015 there were around 900,000 people in Britain with four or more illnesses after analysing previous studies.

This figure is expected to reach 2.4 million by 2035, the researchers claimed.Again, it's not ageing per se that lowers libido and sexual activity, but events and circumstances that typically accompany ageing.

Brain function decreases because of age

Not true. Our neurons work differently in older age, and older people can have difficulties with thinking and remembering.

But, as with sex, these abilities are strongly influenced by our social circumstances.

For example, mental abilities are closely linked to supportive social relationships and physical and mental activity.

Because we can change our social circumstances, we are likely able to offset the physical effects of ageing on our mental abilities.

We often treat young and middle-aged people's mental abilities as the gold standard, but this is biased and leads to false conclusions.

As we get older, we may think differently and at different speeds (we have more to remember), but this doesn't make our thinking less keen, deep, creative, productive or meaningful.

After all Peter Roget invented the thesaurus at 76 and Michelangelo drew up architectural plans for the Basilica of Saint Mary of the Angels and the Martyrs at 88.

You become more conservative

Not so. Imagine ten people: one aged ten, one 20, one 30 and so on.

The oldest is less liberal than the 60-year-old, who is less liberal than the 40-year-old, and so on.

You might conclude people get more conservative with age. But you'd be incorrectly assuming that each person started out with the same political outlook.

A 100-year-old woman, born in 1918, formed her baseline political opinions in a very different time.

Dr Rosenfeld said it was untrue that adults become more conservative as they grow older

What was liberal in the 1940s is conservative now (consider race relations, feminism and sexual norms).

What you're seeing is a 100-year-old whose political opinions have become less conservative, but remain more conservative than her children's or grandchildren's opinions, who began their lives on a more liberal footing.

This is what researchers in the US found in their study of political attitudes among different age groups over 30 years.

They concluded that 'change is as common among older adults as younger adults'.

ARE OLDER PEOPLE HAPPIER THAN THEY EVER HAVE BEEN?

Almost two thirds of older people claim that they are 'happier than they have ever been', a poll suggested in April 2017.

Some 63 per cent of people over the age of 70 feel more content than at any other point in their lives, according to data from the Royal Voluntary Service.

And half claimed they are in the prime of their life.

Worrying less and having more time for personal activities were some of the things highlighted as a benefit of growing older.

No longer caring what people think was also mentioned by the 1,500 British adults questioned by the charity.

You become less happy

Happily, this is untrue.

As a sociologist at the University of Chicago found, while happiness dips between the ages of 30 to 40, 'overall levels of happiness increase with age, net of other factors'.

Why? First, younger people may be exposed to stressful events that older, retired, people are protected from, such as dips in wages or periods of unemployment.

Second, the older we get, the more we tend to focus on positive memories and information, and the better we become at regulating our emotions.

And this upward trend continues until we're 'essentially dying'.

Your immune system weakens

It does, overall, but older people's immune systems vary enormously. Remember the 100-year-old who become more liberal over time?

She would have been 11 when the Great Depression began.

As a result, she would probably have undergone puberty while financially, socially and nutritionally stressed.

Poor nutrition would have weakened her immune system in the immediate and the longer term.

As researchers in France have found, being malnourished weakens the immune system, especially the very young and the very old, so if our 100-year-old woman was undernourished as an older woman, she'd be doubly disadvantaged on the immunity front.

But she might also be less likely to catch a cold. We become immune for years, and sometimes even for a lifetime, to a specific virus after we are infected with it.

Over time, we become immune to more and more viruses, so, the older we get, the fewer viruses can make use sick – assuming, of course, that we're not deluged by a mass of new viruses.

Again, it's how we connect – and have connected – with the outside world that shapes our older age.

Strokes: How to Save the Little Gray Cells

Health Editor’s Note: Having a stroke (big medical term for stroke is cerebral vascular accident, CVA) does not need to be the end of your world as you know it. What causes a stroke?, you ask. A stroke is simply not enough oxygenated blood reaching all of your brain cells, even the gray cells as the fictional, but quite enigmatic Agatha Christie character, Hercule Poirot, will point out as his most important, “able to solve mysteries” part. Oh, but let me get back to the reason for this article.

A decrease in oxygenated blood flow can be due to bleeding, when a blood vessel ruptures and blood flows into the brain tissue, or when a blood clot reaches an area too small to pass through and stops the flow of blood to any portion of the brain beyond that clot. This article mostly addresses “blood clot” causing strokes.

What are the symptoms of having a stroke? These symptoms may be noticed by those around you, before you will notice.

You may be talking and suddenly whomever you are talking to will hear gibberish come out of your mouth.
Your words will not make sense in the context of how you are speaking them.
You may loose the ability to move your face, leg, arm, usually on one side of the body.
You may not understand what others are saying to you.
There may be a loss of vision in one or both eyes.
You might feel dizzy.
You may have trouble walking or loose balance or coordination.
You may have a severe, sudden headache.
When asked to stick your tongue out, your tongue may go to the right or left and not be centered as it exits the mouth.

An explanation of medical terms used in this article are in order. Thrombectomy is physical removal of the blood clot. Lysis means breaking down the clot, with a clot busting drug given by IV.

A stoke is a medical emergency and you need to be at the hospital ASAP. Now, as this article will point out, the time frame to assist you and to improve your chances of not having permanent disabilities brought on by brain tissue death, has become longer and that is a good thing…….Carol

Guidelines Extend Thrombectomy Window to 24 Hours

Comprehensive update from AHA/ASA also expands lytic criteria

by Crystal Phend, Senior Associate Editor, MedPage Today January 24, 2018

LOS ANGELES — In a radical move for the typically glacial pace of comprehensive guideline overhaul, the American Heart Association/American Stroke Association expanded the treatment window for endovascular thrombectomy within hours of release of supporting trial data.

The guideline, released here at the International Stroke Conference (ISC) and online in Stroke, moved from a 6-hour time frame for stent retriever use to up to 24 hours after patients with acute ischemic stroke were last known to be well.

The recommendation was class Ia for the period from 6 to 16 hours as both the DAWN trial and the DEFUSE 3 trial, released the same day here at ISC, confirmed better outcomes than medical therapy alone; it was a IIa recommendation out to 24 hours, reflecting that only a single trial for this window (DAWN) was available.

“This will be perhaps a once in a lifetime situation where a study gets published [and] within 2 hours is incorporated into new guidelines,” DEFUSE 3 presenter Gregory Albers, MD, of Stanford University in Stanford, California, said at a press conference. He noted that this was made possible by provision of an embargoed copy of the trial to the guideline-writing group.

The guidelines recommend physicians use either DAWN or DEFUSE 3 criteria for determining which large vessel occlusions are candidates for clot removal. DEFUSE 3 used broader inclusion characteristics (mainly in allowing a larger ischemic core and less severe strokes), with about 40% of participants not fitting DAWN criteria.

Basically, that comes down to being as generous as possible in inclusion to reach “anybody who is eligible based on either one” before the 16-hour window, but follow DAWN criteria from past 16 hours to 24 hours, guideline writing committee chair William Powers, MD, of the University of Chapel Hill in North Carolina, told MedPage Today at the press conference.

While Mark Alberts, MD, of Hartford HealthCare in Hartford, Connecticut, noted that his center had already adopted the 24-hour strategy based on DAWN, they will consider the two in resetting criteria. “Our stroke staff will meet and we’ll discuss them. I think that’s what’s going to go on in most systems; they’ll come up with a happy medium.”

That also necessitated a shift to the guidelines recommending more sophisticated imaging, specifically diffusion weighted MRI or MRI perfusion to aid in patient selection for mechanical thrombectomy.

In practical terms, these changes are likely to increase the thrombectomy-eligible population by 20% nationwide, commented Jeffrey Saver, MD, of the University of California Los Angeles.

“Now … it doesn’t matter where you are, there’s nowhere in the country that you can’t get to a [thrombectomy] center in 24 hours,” Albers noted.

However, “there’s a lot of work to be done,” toward the class Ia recommendation for development of regional systems of care that remained unchanged from the 2015 update, Powers noted. Each individual region has many issues to work out with “no easy recipe” that all can follow, he said.

Now adding the complexities of thrombectomy scans and transfers, “it’s a new world,” agreed Albers.

Thrombolytics, too, saw some changes in the guidelines. Overall, the recommendations for IV thrombolysis were broadened, with an increase in indications and reduction in absolute contraindications, such as recent dural puncture or non-major head trauma. Use in otherwise eligible patients with mild stroke even in 3 to 4.5 hour windows was also deemed reasonable.

Other changes included:

Prevention of deep vein thrombosis for immobile patients during the hospital stay should focus on intermittent pneumatic compression (upgraded to class I) instead of heparin, which was downgraded from a Ia to IIb recommendation

Candidates for carotid endarterectomy should be evaluated for that within 24 hours and surgery should occur within 7 days after

Acute blood pressure management recommendations got downgraded to reflect increasingly equivocal evidence of benefit

The guidelines were also endorsed by the American Association of Neurological Surgeons, Congress of Neurological Surgeons, and the Society for Academic Emergency Medicine.