Studying bat skulls, evolutionary biologists discover how species evolve

‘This study conducted during the International Year of the Bat offers a clear example of how the evolution of new traits, in this case a skull with a new shape, allowed animals to use new resources and eventually, to rapidly evolve into many new species’

A new study involving bat skulls, bite force measurements and scat samples collected by an international team of evolutionary biologists is helping to solve a nagging question of evolution: Why some groups of animals develop scores of different species over time while others evolve only a few. Their findings appear in the current issue of Proceedings of the Royal Society B: Biological Sciences.

To answer this question, Elizabeth Dumont at the University of Massachusetts Amherst and Liliana Dávalos of Stony Brook University together with colleagues at UCLA and the Leibniz Institute for Zoo and Wildlife Research, Berlin, compiled large amounts of data on the diet, bite force and skull shape in a family of New World bats, and took advantage of new statistical techniques to date and document changes in the rate of evolution of these traits and the number of species over time.

Caption: The skulls and faces of a nectar-eating bat (left) an insect-eating bat (middle) and a fruit bat (right). The short skulls of fruit bats allow them to bite harder than nectar or insect-eating bats. Credit: Elizabeth Dumont, UMass Amherst

They investigated why there are so many more species of New World Leaf-Nosed bats, nearly 200, while their closest relatives produced only 10 species over the same period of time. Most bats are insect feeders, while the New World Leaf-Nosed bats eat nectar, fruit, frogs, lizards and even blood.

One hypothesis is that the evolution of a trait, such as head shape, that gives access to new resources can lead to the rapid evolution of many new species. As Dumont and Dávalos explain, connecting changes in body structure to an ecological opportunity requires showing that a significant increase in the number of species occurred in tandem with the appearance of new anatomical traits, and that those traits are associated with enhanced resource use.

“If the availability of fruit provided the ecological opportunity that, in the presence of anatomical innovations that allowed eating the fruit, led to a significant increase in the birth of new species, then skull morphology should predict both diet and bite force” they said. They found support for these predictions by analyzing thousands of evolutionary trees of more than 150 species, measuring over 600 individual bat skulls of 85 species, testing bite force in over 500 individual bats from 39 species in the field and examining thousands of scat samples to identify the bats’ diets.

They found that the emergence of a new skull shape in New World Leaf-Nosed bats about 15 million years ago led to an explosion of many new bat species. The new shape was a low, broad skull that allowed even small bats to produce the strong bite needed to eat hard fruits. The rate of birth of new species jumped as this new shape evolved, and this group of bats quickly increased the proportion of fruit in their diet. Change in shape slowed once this new skull had evolved.

It can be difficult for evolutionary biologists to demonstrate that traits related to anatomical changes, also called “morphological innovations” such as a new skull shape, give certain groups a survival advantage when new food sources, such as hard fruits, become available.

“This study conducted during the International Year of the Bat offers a clear example of how the evolution of new traits, in this case a skull with a new shape, allowed animals to use new resources and eventually, to rapidly evolve into many new species,” Dumont says. “We found that when a new ecological niche opened up with an opportunity for bats that could eat hard fruits, they shifted their diet significantly, which in turn led to the evolution of new species.”

Featured Video: Studying Bats

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Targeting Bacterial Gas Defenses Allow for Increased Efficacy of Numerous Antibiotics

Science Daily — Although scientists have known for centuries that many bacteria produce hydrogen sulfide (H₂S) it was thought to be simply a toxic by-product of cellular activity. Now, researchers at NYU School of Medicine have discovered H₂S in fact plays a major role in protecting bacteria from the effects of numerous different antibiotics.

In the study led by Evgeny Nudler, PhD, the Julie Wilson Anderson Professor of Biochemistry at NYU School of Medicine, researchers found evidence that H₂S acts as a general defense mechanism against oxidative stress, the process through which many antibiotics kill bacteria.

This information provides the basis for developing new techniques to suppress this universal bacterial defense mechanism and make bacteria more susceptible to antibiotics at lower doses. It also paves the way for reversing antibiotic resistance in human pathogens such as Staphylococcus, Pseudomonas,E. coli, and many others.

The study's findings were published online on November 17 edition ofScience.

"Surprisingly little has been known about H₂S biochemistry and physiology in common bacteria" said Dr. Nudler. "We are excited about the potential impact this research may have on the growing problem of microbial resistance. These findings suggest a conceptually new approach, an adjuvant therapy that targets bacterial gas defenses and thus increases the efficacy of many clinically used antibiotics."

More specifically, the study showed that integrated mechanism of H₂S-mediated protection against oxidative stress also protects against antibiotics. The research provides direct support for the emerging concept of the pro-oxidative action of many antibiotics.

In addition, the study demonstrates that bacteria that generate both H₂S and nitric oxide (NO) simultaneously, such as B. anthracis (a causative of anthrax), cannot survive without both gases, even under normal growth conditions. One gas makes up for the lack of the other and at least one of them is essential.

In a previous study Dr. Nudler and his colleagues demonstrated that NO plays a similar role in protecting bacteria from antibiotics (Science September 9, 2009). However, because NO is present in only a limited number of bacteria while hydrogen sulfide synthesis occurs in essentially all bacteria, the practical implications of this new finding is extremely wide-ranging.

'Language gene' speeds learning

Mouse study suggests that mutation to FOXP2 gene may have helped humans learn the muscle movements for speech.

Ewen Callaway

 

A mutation that appeared more than half a million years ago may have helped humans learn the complex muscle movements that are critical to speech and language.

The claim stems from the finding that mice genetically engineered to produce the human form of the gene, called FOXP2, learn more quickly than their normal counterparts.

The work was presented by Christiane Schreiweis, a neuroscientist at the Max Planck Institute (MPI) for Evolutionary Anthropology in Leipzig, Germany, at the Society for Neuroscience meeting this week in Washington DC this week.

Water-cooler moments may owe their existence partly to a mutation that wires our brain for faster learning.

RISER/GETTY IMAGES

Scientists discovered FOXP2 in the 1990s by studying a British family known as 'KE' in which three generations suffered from severe speech and language problems¹. Those with language problems were found to share an inherited mutation that inactivates one copy of FOXP2.

Most vertebrates have nearly identical versions of the gene, which is involved in the development of brain circuits important for the learning of movement. The human version of FOXP2, the protein encoded by the gene, differs from that of chimpanzees at two amino acids, hinting that changes to the human form may have had a hand in the evolution of language².

A team led by Schreiweis’ colleague Svante Pääbo discovered that the gene is identical in modern humans (Homo sapiens) and Neanderthals (Homo neanderthalensis), suggesting that the mutation appeared before these two human lineages diverged around 500,000 years ago³.

Altered squeaks

A few years ago, researchers at the MPI Leipzig engineered mice to make the human FOXP2 protein⁴. The ‘humanized’ mice were less intrepid explorers and, when separated from their mothers, pups produced altered ultrasonic squeaks compared to pups with the mouse version of FOXP2.

Their brains, compared with those of normal mice, contained neurons with more and longer dendrites — the tendrils that help neurons communicate with each other. Another difference was that cells in a brain region called the basal ganglia were quicker to become unresponsive after repeated electrical stimulation, a trait called ‘long-term depression’ that is implicated in learning and memory.

At the neuroscience meeting, Schreiweis reported that mice with the human form of FOXP2 learn more quickly than ordinary mice. She challenged mice to solve a maze that involved turning either left or right to find a water reward. A visual clue, such as a star, along with the texture of the maze's surface, showed the correct direction to turn.

After eight days of practice, mice with the human form of FOXP2 learnt to follow the clues to the water 70% of the time. Normal mice took an additional four days to reach this level. Schreiweis says that the human form of the gene allowed mice to more quickly integrate the visual and tactile clues when learning to solve the maze.

In humans, she says, the mutation to FOXP2 might have helped our species learn the complex muscle movements needed to form basic sounds and then combine these sounds into words and sentences.

Another MPI team member, Ulrich Bornschein, presented work at the neuroscience meeting showing that the changes to brain circuitry that lead to quicker learning come about with just one of the two amino-acid changes in the human form of FOXP2. The second mutation may do nothing.

 “That makes sense,” says Genevieve Konopka, a neuroscientist at the University of Texas Southwestern Medical Center in Dallas, who also studiesFOXP2. Carnivores, including dogs and wolves, independently evolved the other human FOXP2 mutation, with no obvious effect on their brains.

Faraneh Vargha-Khadem, a neuroscientist at University College London who has studied the KE family in which FOXP2 is mutated, thinks that the new findings could help explain the gene's role in perfecting the facial movements involved in speech.

But she does not see how changes in basic learning circuitry could explain how FOXP2 helps humans to automatically and effortlessly translate their thoughts into spoken language. “You are not deciding how you are going to move your muscles to form these sounds,” she says.

Nature

doi :10.1038/nature.2011.9395

References

1. Lai, C. S., Fisher, S. E., Hurst, J. A., Vargha-Khadem, F. & Monaco, A. P. Nature 413, 519–523 (2001).
2. Enard, W. et al. Nature 418, 869–872 (2002).
3. Krause, J. et al. Curr. Biol. 17, 1908–1912 (2007).
4. Enard, W. et al. Cell 137, 961–971 (2009).

Source: Nature
http://www.nature.com/news/language-gene-speeds-learning-1.9395?WT.ec_id=NEWS-20111122

 

Posted by
Robert Karl Stonjek

How we (should) decide: Philosopher aims to develop theories of practical rationality

 

Caspar Hare is interested in your choices. Not the ones you’ve already made, but the ones you will make, and how you’ll go about making them. The more important, the better.

By way of example, suppose you’re deciding between two careers: journalism and physics. You enjoy both, but for different reasons: Journalism lets you interact with a broad swath of society, exercise your passion for writing and reach a wider audience; physics, though, represents the allure of science, with the freedom to chart a research trajectory at the forefront of human knowledge.

Suppose, too, for argument’s sake, that you had a pretty good idea of how each career would turn out. Either way, you’d be successful and recognized within your field. You’d live in a desirable location and make a good salary.

In your mind, the two options — call them J and P — are so equally and oppositely attractive that you truly cannot decide. But now suppose someone threw a third option into the mix: another journalism career, J*, identical to the first but paying an extra $50 a year. You probably prefer J* to J — why not? But do you prefer J* to P?

If you’re like most people, the answer is “not really.” Fifty dollars a year is not enough to sway you between two choices that are so radically different. And yet this outcome poses a big problem for traditional theories of rationality. Hare, a newly tenured associate professor of philosophy at MIT, studies this problem, which is known to philosophers as “negative intransitivity.” And he’s had to make some career choices of his own along the way.

Incommensurate values

To understand negative intransitivity, first recall the transitive property: If you prefer A to B and B to C, then you prefer A to C.

Preferences that are transitive, Hare says, should also be negatively transitive, meaning that “if you’re indifferent between A and B and indifferent between B and C, you should also be indifferent between A and C.” But that’s not the case in the above example: Most people say they’re indifferent between J and P and also between P and J*, but they prefer J* to J. Does that make them irrational?

Not necessarily, Hare says; it just means that we need to augment our ideas about rationality.

“I’m trying to expand the theory of practical rationality so that it applies to people whose preferences fall into that structure,” he says. “When things like money are at stake, it’s fairly easy to represent preferences with numbers. But if other things are at stake, it’s not so easy. It’s particularly hard when the two things exemplify really different kinds of values — when they’re good in really different ways.”

Hare thinks the key is to use not just single functions to represent preferences, but sets of functions, adding dimensions of complexity that will allow for multiple levels of comparison. Then, choices could be ranked based on the outcomes of all the functions in the set of functions that represent them. Though the modeling can get abstract, Hare says the focus is ultimately on applying the model to practical, real-world scenarios.

“Given that you have certain desires and certain beliefs, the idea that is you could use this [model] to tell you what you ought rationally to do in a given situation,” Hare says.

Coming around to philosophy

So where did “philosophy professor” rank on Hare’s own list of career choices? Hare, who grew up in London, says for the first half of his life, it didn’t even occur to him.

“I was not a very academically inclined person at all. [As a teenager] I’d started reading some philosophy, but I never really associated it as something you did in school. In fact, it always seemed like the anti-school,” Hare says, adding that he attended a “rigid” boarding school that focused on tests and rote memorization.

“Philosophy seemed incredibly anarchic because you got to question the fundamental assumptions of all these disciplines,” Hare continues. Still, he says it never crossed his mind to make philosophy “a serious academic pursuit.”

Even while attending Wesleyan University in Connecticut, Hare majored in intellectual history, but didn’t necessarily focus on philosophy. After a brief stint back in England working on the business end of the Financial Times, Hare, now 39, realized that he could turn his side interest into a career.

He returned to the United States to earn a master’s degree at Stanford University and a PhD at Princeton University, tackling problems in normative ethics and metaphysics. Hare’s first book, On Myself, And Other, Less Important Subjects (Princeton University Press, 2009), was a partial revival of the theory of solipsism, in which he claims that the fact that one’s own self has a special status in the world need not preclude us from making sound moral judgments involving others.

‘There’s nothing you can’t think’

Indeed, it’s this ability to reason about morality, instead of simply relying on emotional gut reactions, that Hare considers one of philosophy’s greatest offerings to the next generation.

“What people, and young people in particular, think about moral questions is powerfully influenced by emotional responses that they have — in particular, disgust-related emotional responses, which are acquired via socialization,” Hare says. “It’s good for people to be able to step back and think about how to respond to a moralized case not by just saying, ‘How do I immediately feel about this? Does it set off my ‘yuck response’?’ but knowing how to think carefully about it and really evaluate what’s going on.”

At MIT, Hare enjoys teaching and working with students. Quite a few undergraduates take at least one philosophy class during their time at the Institute, he says, which he believes helps them learn to think in a “disciplined way,” no matter what their career path.

“In philosophy, there’s nothing you can’t think,” Hare says. “Everything’s on the table, and the values are all about rigor and clarity, exploring how to use a thought and seeing where it goes.” 

---

This story is republished courtesy of MIT News (http://web.mit.edu/newsoffice/), a popular site that covers news about MIT research, innovation and teaching.

Provided by Massachusetts Institute of Technology

"How we (should) decide: Philosopher aims to develop theories of practical rationality." November 22nd, 2011.http://www.physorg.com/news/2011-11-philosopher-aims-theories-rationality.html

 

Posted by
Robert Karl Stonjek

Thanksgiving 2011

“Yogis cannot reach Krishna, but for pure devotees like mother Yashoda, Krishna is already caught.” (Shrila Prabhupada, Shrimad Bhagavatam, 10.9.9 Purport) With the hustle and bustle that comes with the feverish pursuit to procure enough wealth and provisions to support oneself and a family, even a holiday turns into a time of turmoil, adding pressure to a day that is meant to relieve it. The increase in obligations is especially true with the Thanksgiving holiday.  Though carrying issues relating to travel and the comingling with family members you may not have seen in a long time, Thanksgiving is meant to be a day of prayer and remembrance, a time to give thanks to the Almighty for the bountiful gifts he heaps upon us. Thanksgiving brings the inevitable question of what we are thankful for. For the spiritualist trying to reach a better end in both this life and the next, there is one aspect to their practices that provides endless gifts, which can be appreciated every day, including on Thanksgiving. The first Thanksgiving celebrated a bountiful harvest that resulted from a major shift in the way food was produced inside of a small community. Settlers to what would be known as the New World had a difficult time in the beginning. There were very few colonists who had fled England for the “greener” pastures of America, but when they arrived after a long boat ride conditions were so unexpectedly harsh that many of them died during the first winter. To further add to their troubles, the colonists found that their food production was quite sparse, for everything was placed into a common store, to be shared by all the members of the community. The governor of this group decided to shift gears, assigning a plot of land to each family, with the fruits of labor remaining in their possession. As a result, the next harvest was so large that not only was the starvation problem solved, but free trade with the neighboring native Americans could take place as well. Deciding that the harvest was too grand to let pass without commemoration, the Pilgrims held a grand feast, where there was an overwhelming feeling of gratitude. They thanked the Lord for their ability to eat and survive. The tradition then continued annually even into the founding of the United States of America, with George Washington, the first president, declaring the holiday be dedicated to serving the Supreme Lord, a time to give thanks for all that He has given. “Whereas it is the duty of all Nations to acknowledge the providence of almighty God, to obey his will, to be grateful for his benefits, and humbly to implore his protection and favor…Now therefore I do recommend and assign Thursday the 26th day of November next to be devoted by the People of these States to the service of that great and glorious Being, who is the beneficent Author of all the good that was, that is, or that will be…” (President George Washington, Thanksgiving Day 1789, A Proclamation) In the Vedic tradition, the oldest system of spirituality known in the world, there are different ways to reach the Supreme Absolute Truth, the source of everything. In any endeavor, there are multiple avenues one can travel down to reach their desired destination. Usually the one that is the simplest to implement is considered the best, but sometimes the simplest doesn’t equate to the easiest to accept. For instance, in weight loss, the easiest option to implement is a reduction in eating. Just don’t eat as much as you are now and you will lose weight. While reducing food intake is easy, accepting the option is difficult, for the individual is accustomed to act otherwise, especially when there are culinary delights available at every corner. Instead of curbing eating directly, roundabout options, such as exercise, diets involving specific foods, and tight controls on the combination of foods consumed, are accepted. For realizing God, there is one simple and surefire method. This option is the easiest to implement but the most difficult to accept. Because this option is available to the most number of people, God is represented fully within it. The other avenues only have God represented partially and thus only bring the Lord’s partial association. A famous incident documented in the Shrimad Bhagavatam   , or Bhagavata Purana, serves as an example to illustrate the difference. A Purana is a collection of ancient stories, historical incidents discussed between spiritual masters and their disciples. The events are not always presented in chronological order nor do they take place only on this planet, but they nevertheless reveal so much about spirituality, the position of the essence of identity, and what it takes to fulfill the primary mission in life. The Bhagavatam states that the Supreme Absolute Truth, the Personality of Godhead Himself, descended to earth around five thousand years ago in Vrindavana   , a small farm community. The fact that God can come to earth and behave like a child is very difficult to accept even for advanced spiritualists. The first instruction taught to aspiring transcendentalists in the Vedic tradition is that the individual living being is not their body. The outer covering is just a shell that comes together, shifts in appearance, and then ultimately gets destroyed. The soul is what counts, as it is not slain when the body is slain. If we are not our body, then surely someone who is the fountainhead of all spirit and matter cannot be the same as His body when He comes to earth. The body has a strong influence, however, which operates through the illusory energy known as maya. Since we living entities are affected by maya, how can the Supreme Lord have the same defect? Either He is subject to maya also - which thus makes Him equal to us - or the listed incarnations aren’t really God but just some exalted personalities who had extraordinary abilities. “Unintelligent men, who know Me not, think that I have assumed this form and personality. Due to their small knowledge, they do not know My higher nature, which is changeless and supreme.” (Lord Krishna, Bhagavad-gita   , 7.24) Lord Krishna   , the original Personality of Godhead who came to Vrindavana, addresses this issue in the Bhagavad-gita, a talk on spirituality held much later on during Krishna’s time on earth. For God there is no difference between spirit and matter. Matter is only under maya’s influence for those who have no control over maya. God is the creator of both the spiritual and material energies, so He is never subject to either’s influence. He retains this standing even when appearing on earth in the form of a small child. If God stays above matter and doesn’t require self-realization when coming to earth, why even make an appearance? Ah, here is where the opportunity for giving thanks comes in. In the roundabout methods of spirituality, different aspects of the Supreme Lord are uncovered. Even an atheist is a kind of spiritualist, though they don’t know who God is or that He exists. Rather, the atheist recognizes Krishna’s external energy expansion of maya, or material nature. Even in the theory of evolution, which is seen as the antithesis of the spiritual doctrine, a higher power is acknowledged. That stronger force is nature, which assumes the responsibility for the purported changing in the species. Even though such theories are based in ignorance, there is still an acknowledgement of one of Krishna’s energies. Since the Lord has no personal presence in the material energy, His personal association is denied such followers. The jnanis and yogis connect with aspects that have more of Krishna’s influence. Instead of seeing material nature as the cause, jnanis consider the impersonal spiritual energy known as Brahman as the highest force. Think of how each individual has a spark of life inside of them that guides their activities. Then carry that same discernment across every autonomous being, from the tiny ant all the way up to the large elephant. In this way we see that there is a total collection of the spiritual energy, almost a singular energy in a sense. This force is known as Brahman, and it is beyond the dualities created by maya. The jnanis, through study of Vedanta philosophy, worship this energy. Though Brahman is pure spirit, it again lacks Krishna’s personal presence. The yogis try to catch Krishna through His feature of Paramatma, which is the plenary expansion residing within the heart next to the individual soul. With Brahman the sum collection of energy is recognized, and with the Paramatma the localized aspect is honored, but in either case Krishna’s transcendental features are not noticed. Brahman and Paramatma can be described as nirguna, or without attributes, for the spiritualist connecting with these features doesn’t notice the qualities of sweetness belonging to the Personality of Godhead. God isnirguna in the sense that He never possesses material attributes, but at the same time He has spiritual features that can appear contradictory. Krishna is both formless and with form. He has eyes and doesn’t. He has legs and at the same time doesn’t. How can the human brain make light of these contradictions? The Supreme Personality of Godhead, Bhagavan, in His forms known as saguna, or with attributes, descends to earth every now and then to show the devoted souls what it means to have spiritual attributes. As Krishna, the Lord came to Vrindavana in His original form, one which was full of sweetness. The benefit of Bhagavan’s association is that anyone can connect with Him. Practicing meditational yoga and studying Vedanta are very difficult, thus the two disciplines are exclusive. Their necessary requirements automatically prohibit entry. The jnani must be very intelligent, capable of understanding high logic. The yogi must be renounced, capable of sitting in meditation for hours on end and blocking out the distractions of material life. To connect with Bhagavan one must follow bhakti-yoga, which is available to every person, even if they are seemingly materially entangled. The residents of Vrindavana five thousand years ago weren’t jnanis or yogis, and they had never practiced self-realization. Nevertheless, they got to catch Krishna, to hold Him in their arms and bask in His sweet vision. How was this possible? They practiced bhakti, though they weren’t cognizant of the fact. Through many austerities from previous lives and a pious attitude guiding their activities, these residents were fully deserving of Krishna’s company. As they weren’t jealous of Him, why wouldn’t the Lord choose their land as the place to come and enact His pastimes? The residents of Vrindavana were certainly thankful for Krishna’s association, and the people who hear from the Shrimad Bhagavatam can share the same sentiments. One time, the child Krishna broke a pot of butter belonging to His mother Yashoda. When she came upon the broken pot, she knew that it was Krishna’s work, for He was angry that she had gotten up while feeding Him to tend to a pot of boiling milk on the stove. When she returned, Yashoda saw the broken pot and then found the culprit Krishna feeding butter and yogurt to monkeys. Delighting in the scene, Mother Yashoda was ready to catch her son and punish Him for His transgression. Seeing Mother Yashoda with her whipping stick in hand, Krishna started to run away, pretending to be afraid. Though yogis and jnanis can’t catch Krishna, Mother Yashoda, a cowherd woman without much speed herself, was able to catch the Supreme Lord and bind Him in her motherly affection. The Lord allowed His dear mother to catch Him and execute her motherly duties, which gave her so much pleasure. From that association both sides felt tremendous delight, for the natural positions of the Supreme Lord and His devotees    were on display. On Thanksgiving we can give thanks to the Supreme Lord for having descended to earth to engage in these pastimes. Karma, yoga and jnana are available to try, but only through bhakti will we get Krishna’s association. The Shrimad Bhagavatam is a bhakti-shastra, a scriptural work focused on devotional service   . Because of its contents, the Bhagavatam is as good as Krishna. It is honored as such in the homes of Krishna devotees. The vision of Krishna being chased by Mother Yashoda and her whipping stick cannot be remembered enough. For having this most heartwarming vision, we are forever thankful. The incident is so sweet that one only hopes to be able to give thanks for it every single day, for with remembrance comes Krishna’s association, which continues into the afterlife for anyone who is so desirous. In Closing: Seeing mother’s presence Krishna started to run, Knew He did something bad, with mother enjoyed the fun. A whipping stick in her hand to punish she took, Trouble catching son, for not was she fleet afoot. Materialist the presence of God can never see, Brahman and Paramatma for jnani and yogi. But Yashoda caught Krishna by bhakti following, With ropes of affection her young son binding. Thankful we are for that scene so pleasurable, Krishna caught by mother’s love, a pastime so delightful.

Al ain paradise united arab emirates

AL AIN PARADISE.....The First park in Guinness World Record by The Largest Number of Hanging Flower Baskets---Al Ain, United Arab Emirates.

Implanted neurons, grown in the lab, take charge of brain circuitry

Among the many hurdles to be cleared before human embryonic stem cells can achieve their therapeutic potential is determining whether or not transplanted cells can functionally integrate into target organs or tissues.

Writing today in the Proceedings of the National Academy of Sciences, a team of Wisconsin scientists reports that neurons, forged in the lab from blank slate human embryonic stem cells and implanted into the brains of mice, can successfully fuse with the brain’s wiring and both send and receive signals.

Neurons are specialized, impulse conducting cells that are the most elementary functional unit of the central nervous system. The 100 billion or so neurons in the human brain are constantly sending and receiving the signals that govern everything from walking and talking to thinking. The work represents a crucial step toward deploying customized cells to repair damaged or diseased brains, the most complex human organ.

“The big question was can these cells integrate in a functional way,” says Jason P. Weick, the lead author of the new study and a staff scientist at the University of Wisconsin-Madison’s Waisman Center. “We show for the first time that these transplanted cells can both listen and talk to surrounding neurons of the adult brain.”

The Wisconsin team tested the ability of their lab grown neurons to integrate into the brain’s circuitry by transplanting the cells into the adult mouse hippocampus, a well-studied region of the brain that plays a key role in processing memory and spatial navigation. The capacity of the cells to integrate was observed in live tissue taken from the animals that received the cell transplants.

Weick and colleagues also reported that the human neurons adopted the rhythmic firing behavior of many brain cells talking to one another in unison. And, perhaps more importantly, that the human cells could modify the way the neural network behaved.

A critical tool that allowed the UW group to answer this question was a new technology known as optogenetics, where light, instead of electric current, is used to stimulate the activity of the neurons.

“Previously, we’ve been limited in how efficiently we could stimulate transplanted cells. Now we have a tool that allows us to specifically stimulate only the transplanted human cells, and lots of them at once in a non-invasive way,” says Weick.

Weick explains that the capacity to modulate the implanted cells was a necessary step in determining the function of implanted cells because previous technologies were too imprecise and unreliable to accurately determine what transplanted neurons were doing.

Embryonic stem cells, and the closely related induced pluripotent stem cells can give rise to all of the 220 types of tissues in the human body, and have been directed in the lab to become many types of cells, including brain cells.

The appeal of human embryonic stem cells and induced pluripotent cells is the potential to manufacture limitless supplies of healthy, specialized cells to replace diseased or damaged cells. Brain disorders such as Parkinson’s disease and amyotrophic lateral sclerosis, more widely known as Lou Gehrig’s disease, are conditions that scientists think may be alleviated by using healthy lab grown cells to replace faulty ones. Multiple studies over the past decade have shown that both embryonic stem cells and induced cells can alleviate deficits of these disorders in animal models.

The new study opens the door to the potential for clinicians to deploy light-based stimulation technology to manipulate transplanted tissue and cells. “The marriage between stem cells and optogenetics has the potential to assist in the treatment of a number of debilitating neurodegenerative disorders,” notes Su-Chun Zhang, a UW-Madison professor of neuroscience and an author of the new PNAS report. “You can imagine that if the transplanted cells don’t behave as they should, you could use this system to modulate them using light.”

-Latest Science News

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In addition to Weick and Zhang, the new PNAS report was co-authored by Yan Liu, also of UW-Madison’s Waisman Center. The study was funded by the U.S. National Institutes of Health.

Violence traced to 129,000 years ago

CHINESE ACADEMY OF Science

The identification of traumatic lesions in human fossils is of special interest because of the underlying behaviours that are involved: accidental or intentional wounding, potential interpersonal violence, and also the social support needed for the care and recovery of impaired individuals. Aside from the Neandertals, secure evidence of healed traumatic lesions is very rare among Pleistocene human remains. The research of the late Middle Pleistocene archaic human cranium from Maba, south China, brings to new evidence that interhuman aggression healed blunt force trauma as early as 129,000 years ago in East Asia. The report published on Monday, 21 November 2011, in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) documents a lunate lesion on the right frontal squamous exocranially concave and ridged lesion with endocranial protrusion. Differential diagnosis indicates that it resulted from localized blunt force trauma due to an accident or, more probably, interhuman aggression. The area of the depressed portion of the vault lesion is 14.0 mm in length and 1.5 mm in its deepest point below the frontal external contour. The center of the depression is rough. Several concentric waves within it created rounded edges, none of which is a complete circle. When the lesion is enlarged, healing of the bone can be seen to have taken place surrounding the area of the depressed area. The trauma is very similar to what is observed today when someone is struck forcibly with stones or staves. Its remodeled, healed condition also indicates the survival of a serious brain injury. It is not possible to assess whether the incident was accidental or intentional, or whether it resulted from a short-term disagreement, or premeditated aggression. Neurocranial abnormalities had been found in Chinese human fossils; however, when evaluated by paleopathological and forensic diagnostic standards, none represents definitely traumatic lesions caused by interpersonal violence. The depressions or damages on the Zhoukoudian H. erectus crania were suspected to hominid agency, but they could be more likely made by geological-crushing from the weight of overlying sediment or carnivores. The lesion on the supraorbital of the Lantian (Gongwangling) calvarium, initially thought to be a healed antemortem trauma, were later ascribed to postmortem taphonomic alterations of the bone. The Middle Pleistocene partial cranium from Hulu Cave, Tangshan, Nanjing, exhibits an ecdocranial healed lesion that was caused by either trauma or burning. Maba cranium was discovered in 1958, in a karst cave at Lion Rock, Maba town, Qujiang district, Shaoguan city, Guangdong province. The Maba cranium and a large quantity of mammal fossils were found in a deep and narrow crevice inside the cave. Maba has a thick, prominent and projecting supraorbital torus that arches over the circular profile orbits. The nasal bones are narrow, pinched and strongly projecting. Since its unique morphology in the middle stage of Early Homo Sapiens from mainland northern eastern Asia, Maba has been described extensively from a comparative morphological perspective. Although lots of researchers studied the Maba partial cranium, no one pay more attention and analysis the special lesion. Using a high-resolution industrial CT scanner and stereomicroscopy, Dr Xiu-jie WU and her co-author suggested that the Maba individual survived from serious injury and post-traumatic disabilities, and that it obviously did not kill the person. Maba would have needed social support and help in terms of care and feeding to recover from this injury long before death. The Maba 1 lesion joins a series of other craniofacial traumatic lesions of Pleistocene humans which provide evidence of both apparently elevated levels of risk to injury and the ability to survive both major and minor conditions. This research was mainly supported by the National Natural Science Foundation of China. (Link: www.pnas.org/cgi/doi/10.1073/pnas.1117113108 Editor's Note: Original news release can be found here.

New tool to track mental health

THE UNIVERSITY OF CANBERRA

Patients with depression can monitor their mental health using a computer as quickly as those with diabetes can manage their condition, thanks to new research presented at the University of Canberra.   The joint research project between the University of Canberra, Queensland Institute of Medical Research and the Black Dog Institute at the University of New South Wales will feature in a workshop to mark the launch of the University of Canberra’s new Human-Centred Computing Laboratory.   University of Canberra researcher Dr Roland Goecke will present research towards a computerised diagnostic aid that can diagnose depression with up to 80% accuracy. The researchers’ next step is to develop a laptop-based prototype.   “Ultimately, we hope to assist patients with depression to monitor the progress of their illness in a way that a patient with diabetes monitors their blood sugar levels with a small portable device,” Dr Goecke said.   Half of all Australians will experience mental illness during their life. Still, despite the high prevalence, current clinical practice depends almost exclusively on self-report and clinical opinion, risking a range of subjective biases, Dr Goecke said.   Dr Goecke and his colleagues have completed a pilot study of their ‘affective computing’ technology on 40 patients and 40 healthy control subjects.   The technology analyses a subject’s mental health by recognising markers of depression, such as movements in the eyebrows and lips, when subjects are exposed to video clips designed to elicit an emotional response.   “The results demonstrate the capacity of affective computing technology to help with and improve the diagnosis of depressive disorders and the monitoring of progress during therapy. As health care costs increase in Australia, providing effective health monitoring systems and diagnostic aides is significant. Affective computing technology can and will play a major role in this,” Dr Goecke added.   The following steps are to identify a new generation of objective ‘markers’ of mental illness in subjects’ expressions and combine physiological, audio and video sensors in a single device to measure depression.   Launched today, the University of Canberra’s new Human-Centred Computing Laboratory will undertake multidisciplinary cutting-edge research ranging from face and gait recognition to forensic voice comparison and fingerprint analysis, from the detection of depressive disorders to the reliable tracking of athletes in field sports and the analysis of their performance. Editor's Note: Original news release can be found here.