Cuba Hosts 6th Workshop of Basic Biomedical Sciences

The 6th Workshop on Basic Biomedical Sciences started today in this capital with a great international participation and the aim to continue raising the level of Cuban health professionals, recognized worldwide.

Today's agenda includes lectures on several issues such as genetics, nutrition, probiotics in medicine and preclinical and clinical data of the amniotic membrane, by renowned specialists from Spain, the United States and several Latin America nations.

This event welcomes doctors, stomatologists, nursing graduates and other specialists who are working or researching in the areas of the Basic Biomedical Sciences, the Cuban News Agency (ACN) stated.

Its objective is to raise the level of teachers and enrich the scientific production of medicine and biomedical science in the Caribbean country, the Head of Dissemination and Information at the University of Medical Sciences in Havana, Cosme More, said.

Courses, trainings and lectures related to the metabolic diseases, biomedical anthropology in vulnerable groups, experimental models in the basic science research, and neuro-protection in degenerative diseases are also included.

The event, which began on April 17th and will conclude tomorrow, is hosted at the 'Victoria de Giron' Institute of Basic and Preclinical Sciences, a leading center in Cuba to train highly qualified medical professionals, the organizing committee said.

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First Known Dinosaur Brain Fossil Discovered

The 133-million-year-old specimen is a stunningly well-preserved sample of mineralized tissue from inside a Cretaceous dinosaur’s skull.

An unassuming lump found on a Sussex beach in 2004 contains the first known fossilized brain tissue from a dinosaur.

The 133-million-year-old fossil belongs to a relative of Iguanodon, an iconic herbivorous dinosaur that lived during the early Cretaceous. The fossil mostly consists of an endocast—a sediment cast of the skull cavity where the dinosaur’s brain resided.

Typically, endocasts give vital but indirect information about the brains of fossilized animals, as these sensitive organs are often the first to decay. But this endocast’s top surface contains microscopic features that appear to be directly mineralized bits of brain tissue.

Fossilized Dinosaur Brain Discovered in England

A piece of a dinosaur's brain has been found in Sussex, England. The fossilized brain tissue is thought to be from a species similar to Iguanodon, large herbivores that lived about 133 million years ago.

Fibrous textures across the endocast surface probably started as pieces of the meninges, the tough, protective membranes that envelop and nurture the brain. Mineralized networks of blood vessels—some smaller in width than a human hair—crisscross the surface. And tantalizingly, ripples in the preserved meninges might trace some of the folds in the cortex, the wrinkled outer layer of the brain.

“That is the nearest I suspect we’re ever going to get to the whole [brain],” says paleontologist David Norman of the University of Cambridge, one of the researchers who worked on the fossil. The remarkable find was announced on October 27 at the Society of Vertebrate Paleontology’s annual meeting in Utah.

High-resolution scans of the fossil revealed signs that the dinosaur’s meninges and overall brain structure resembled those of living birds and crocodilians. Although it’s tricky to extrapolate the dinosaur’s intelligence from the fossil, Norman and his colleagues say that based on it and other endocasts, the animal was at least as smart as modern crocodilians.

Pickled Brains

Soft tissue preservation in fossils is extremely rare, in part because it requires exacting chemical conditions to occur. Previously described dinosaur fossils have captured skin, organs, and even red blood cells. (Read about a fossil fish with an exquisitely preserved heart of stone.)

Based on the brain fossil’s minerals and orientation, Norman and his colleagues believe that the dinosaur sank into a stagnant pond after it died, flipping belly up as it descended to leave its head upside down and partially buried in the lake bed sediments.

The animal’s braincase served as a natural bowl, cradling the collapsed brain as the pond’s acidic, low-oxygen waters essentially pickled its membranes. As the waters ate away at the dinosaur’s blood and bone, the corrosion freed charged atoms that replaced the pickled tissues with minerals—preserving their impressions 133 million years later, down to the microscopic level.

The animal’s braincase served as a natural bowl, cradling the collapsed brain as the pond’s acidic, low-oxygen waters essentially pickled its membranes.

“It looks like a very exceptional specimen, for sure,” says Ohio University paleontologist Lawrence Witmer, an expert on dinosaur brain evolution who wasn’t involved with the study. “Soft tissue preservation of any kind gets us excited, and for those of us looking at the brain, potentially getting a glimpse into what the brain is like blows us away.”

The ancient brain first came to light in late 2004, when fossil hunter Jamie Hiscocks combed the beaches of Bexhill, some 50 miles southeast of London, after a winter storm. As he prowled the fossil-rich shore by torchlight, an unusually shaped object jumped out at him among the piles of rock debris.

In short order, Hiscocks and his brother concluded that the fossil was an endocast—but he remained struck by its unusual preservation, eventually leading him to ask Oxford paleobiologist Martin Brasier for his opinion.

“Martin knew immediately we had something special here, so I agreed to loan the specimen to him,” Hiscocks writes in an email. “In his initial email to me, he asked if I’d ever heard of dinosaur brain cells being preserved in the fossil record. I knew exactly what he was getting at. I was amazed to hear this coming from a world-renowned expert like him.

“Not in my wildest dreams did I ever think I would find anything like this,” continues Hiscocks. And he’s no stranger to significant discoveries: Hiscocks also found the world’s oldest spiderweb fossil, which was described in 2008.

In 2011, Brasier brought the brain fossil to the attention of Norman, his longtime friend and colleague. Norman’s first read: The endocast was mostly made of sediments encrusted with a thin layer of mineralized soft tissue. Brasier, on the other hand, was more bullish about the endocast, holding on to the hope that the fossil was an entire dinosaur brain.

“We then went into this prolonged argumentative debate between friends—the sort of stuff you argue about over a beer,” says Norman. But the two could never agree, leading Norman in 2013 to write down his interpretation of the fossil for Brasier’s reference.

But Brasier never replied to Norman in life: In December 2014, he died suddenly in a car crash, shocking the paleontological community.

A few months later, Brasier’s former Ph.D. student Alex Liu was sorting through Brasier’s papers when he came across Norman’s letter.

“Martin had gone through it in detail, and after each paragraph, [he had written] ‘agreed,’” says Norman. “He had completely turned around to my way of thinking,” he adds, even embracing Norman’s flip-and-pickle explanation for how the tissues mineralized.

Norman and Liu then resumed work on the fossil, conducting additional scans that revealed the extra details. Their paper will be included in a special publication of Earth System Evolution and Early Life from the Geological Society of London honoring Brasier’s life.

Smart Search

Future studies may reveal even more about the potential link between this ancient brain and the noggins of modern animals, including 3-D scans that directly compare the dinosaur’s brain structure to that of bird and crocodilian brains.

Amy Balanoff, a research scientist with Johns Hopkins University’s Center for Functional Anatomy and Evolution, says she isn’t yet fully convinced of the brain tissues, but she looks forward to seeing more detailed information about the fossil.

“Confirmation in science is a long process, and this publication is the first step toward that end,” she writes in an email. “I have a feeling that because this is such a sensational find, it will be thoroughly examined by the scientific community.”

To that end, Hiscocks and Norman are working to place the fossil, currently in Hiscock’s possession, in a publicly accessible museum collection.

Beyond its anatomical value, Norman and Witmer say that the Bexhill fossil’s real significance comes from how it expands the realm of possible tissues that can be preserved in the fossil record.

“These are the kinds of things we don’t expect to see, and what makes this [fossil] so important is that now we can look,” says Witmer. “Things that change our search image wind up being the most important finds.”

Although Norman doesn’t think that fossils like the Bexhill specimen will spark their own research program—he calls it “an interesting one-off”—he says he will double back to endocasts he has examined previously, to be sure he didn’t miss similarly revealing surface features.

“It never really occurred to me that there could be mineralization of the tissues in that area, because the brain is so fragile,” he says. “It’s putting a flag up the pole.”

People who meditate are more aware of their unconscious brain

People who meditate are more aware of their unconscious brain activity – or so a new take on a classic “free will” experiment suggests.

The results hint that the feeling of conscious control over our actions can vary – and provide more clues to understanding the complex nature of free will.

The famous experiment that challenged our notions of free will was first done in 1983 by neuroscientist Benjamin Libet. It involved measuring electrical activity in someone’s brain while asking them to press a button, whenever they like, while they watch a special clock that allows them to note the time precisely.

Typically people feel like they decide to press the button about 200 milliseconds before their finger moves – but the electrodes reveal activity in the part of their brain that controls movement occurs a further 350 milliseconds before they feel they make that decision. This suggests that in fact it is the unconscious brain that “decides” when to press the button.

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In the new study, a team at the University of Sussex in Brighton, UK, did a slimmed-down version of the experiment (omitting the brain electrodes), with 57 volunteers, 11 of whom regularly practised mindfulness mediation. The meditators had a longer gap in time between when they felt like they decided to move their finger and when it physically moved – 149 compared with 68 milliseconds for the other people.

This suggests they were recognising their unconscious brain activity earlier than most people, says Peter Lush, a member of the team, supporting the belief among meditators that it helps them to become more aware of their internal bodily process, he says. Such a result has previously been predicted by the Buddhist scholar Georges Dreyfus.

Spectrum of awareness

The non-meditators were also tested on how well they could be hypnotised. After they were out of any hypnotic trance, the experiment was repeated. Those who could be easily hypnotised felt like they decided to move their finger 124 milliseconds later than did those of low hypnotisability. In fact, the easily hypnotisable group had the sensation of deciding to move 23 milliseconds after their finger had actually moved.

It is not that people who are highly hypnotisable are puppets, says Lush, but that they may have less conscious access to their unconscious intentions.

“Self-awareness of our intention to act is a fundamental part of being human, so anything that affects it is important,” says Stephen Fleming of the Wellcome Trust Centre for Neuroimaging in London. “The results indicate that hypnotisability and mindfulness might be at opposite ends of a spectrum of self-awareness,” he says. Previous research has suggested that people who meditate are less easy to hypnotise and people who can be hypnotised are less “mindful”, in other words, are less aware of their internal bodily processes.

Another study using Libet’s set-up has shown that people who are impulsive also have shorter time intervals between their conscious awareness of an intention to act and the act itself.

However others have criticised drawing broad conclusions from such experiments, saying that giving people an instruction to sit and press a button at some random time-point is an artificial situation and may not be relevant to real-life decisions – like voting in a referendum.

Our first sex with Neanderthals happened 100,000 years ago

It was a two-way street. Many people carry ancient Neanderthal DNA in their genome as a result of cross-species liaisons around 50,000 years ago. Now it seems that some Neanderthals carried our DNA, too.

This particular group had, for example, a big chunk of modern human DNA right in the middle of a gene that may have a role in language development, called FOXP2. What’s more, they got that DNA from us at least 100,000 years ago, somewhere in Eurasia. The finding challenges an idea central to our thinking about human evolution: that our species didn’t properly leave Africa until about 60,000 years ago.

A team led by Sergi Castellano at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, compared 50,000-year-old DNA from four extinct human relatives: a Neanderthal and a Denisovan from Siberia, and two European Neanderthals. They also looked at 500 genomes from living Africans.

Neanderthals and Denisovans are more closely related to each other than they are to us, so their genomes should have more in common, too. But Castellano’s team found that parts of the Siberian Neanderthal genome were more similar to the genomes of modern-day Africans than those of the Denisovans or the European Neanderthals. Statistical analyses ruled out the possibility that those similarities were the result of contamination.

“One chunk of modern DNA found in Neanderthals was inside a gene linked to language development”

The length of the modern-day DNA segments allowed the team to estimate when they entered the Siberian Neanderthal gene pool. Recently added DNA typically exists in long segments that become shorter down the generations. The team concluded that modern humans must have first interbred with Neanderthals at least 100,000 years ago (Nature, DOI: 10.1038/nature16544).

The researchers speculate that this might have happened in the Arabian peninsula or eastern Mediterranean, based on tentative archaeological evidence that modern humans were living in those regions by then. It could also have happened further east – especially in light of the discovery last year of 47 modern human teeth in sediments in south-east China, dated to between 80,000 and 120,000 years old.

 

For many years, hypotheses that significant out-of-Africa migration could have happened that early were considered heretical, says archaeologist Michael Petraglia at the University of Oxford. The idea isn’t so outlandish any more, it seems. “This study is an eye-opener,” says María MartinÓn-Torres at University College London, who was involved in the Chinese finds. “A whole unknown episode is open now to investigate.”

Some researchers were sceptical that modern humans had reached China so early, says MartinÓn-Torres. She thinks the new DNA evidence will help convince them. Chris Stringer at London’s Natural History Museum agrees. “The search is now on for further traces of these mysterious early moderns, and their Neanderthal relatives in Asia,” he says.

It’s possible that Neanderthal DNA affects the health of modern humans (see “Should we fear our inner Neanderthal?“). Might Neanderthals have benefited from gaining modern human DNA, for example, in their version of the FOXP2 gene? “We can’t discount the possibility,” says Mark Pagel at the University of Reading, UK, but figuring it out won’t be easy because FOXP2‘s effects may have been different in Neanderthals and may not have helped them acquire the basics of language.

“It is too early to tell,” says Castellano, whose team is starting to tackle such questions. In other words, the jury is still out.

Should we fear our inner neanderthal?

Some of us have a secret in our genome: DNA that our forebears got from sex with Neanderthals. But does this DNA hold any sway over us?

A team led by Corinne Simonti at Vanderbilt University in Nashville, Tennessee, studied medical records and genetic data from more than 28,000 people of European descent. They found small but significant links between the presence of certain Neanderthal DNA segments and the incidence of medical conditions, including depression and addiction (Science, doi.org/bch3).

“The brain is incredibly complex, so it’s reasonable to expect that introducing changes from a different evolutionary path might have negative consequences,” says Simonti. However, many factors influence susceptibility to health issues, so people without this ancient DNA might still develop depression and those who do carry this DNA might never experience it.

In fact, plenty of “our” DNA has foreign origins – from extinct early humans to viruses – and can have both good and bad effects on health.

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