Posts tagged neuroscience
Articles and news from the latest research reports.
Neurotransmitters Linked to Mating Behavior Are Shared by Mammals and Worms
When it comes to sex, animals of all shapes and sizes tend to behave in predictable ways. There may be a chemical reason for that. New research from Rockefeller University has shown that chemicals in the brain — neuropeptides known as vasopressin and oxytocin — play a role in coordinating mating and reproductive behavior in animals ranging from humans to fish to invertebrates.
"Our research shows that molecules similar to vasopressin and oxytocin have an ancient and evolutionarily conserved role in controlling a critical social behavior, mating," says Cori Bargmann, Torsten N. Wiesel Professor and head of the Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior. "This work suggests that these molecules encode the same kind of information in the brains of very different animals."
Bargmann, whose laboratory studies the relationship between genes, neural circuits and behavior in the C. elegans roundworm, says vasopressin and oxytocin have been implicated in a variety of reproductive and social behaviors in humans and other mammals, including pair bonding, maternal bonding and aggressive and affiliative behaviors. Mice that lack oxytocin may develop social amnesia, and humans who sniff oxytocin through an inhaler change their cooperative behavior in computer games, behaving as though they “trust” other players more.
Eye Movements and the Search for Biomarkers for Schizophrenia
There is a long history of research on impaired eye movements associated with schizophrenia. Using a series of simple viewing tests, researchers of a new paper in Biological Psychiatry explored the ability of these eye movement tests to distinguish people with and without the diagnosis of schizophrenia.
Using their complete dataset, they were able to develop a model that could discriminate all schizophrenia cases from healthy control subjects with an impressive 98.3% accuracy.
Drs. Philip Benson and David St. Clair, lead authors on the paper, agreed that their findings were remarkable: “It has been known for over a hundred years that individuals with psychotic illnesses have a variety of eye movement abnormalities, but until our study, using a novel battery of tests, no one thought the abnormalities were sensitive enough to be used as potential clinical diagnostic biomarkers.”
Their battery of tests included smooth pursuit, free-viewing, and gaze fixation tasks. In smooth pursuit, people with schizophrenia have well-documented deficits in the ability to track slow-moving objects smoothly with their eyes. Their eye movements tend to fall behind the moving object and then catch-up with the moving object using a rapid eye movement, called a saccade.. A picture is displayed in the free-viewing test, and where most individuals follow a typical pattern with their gaze as they scan the picture, those with schizophrenia follow an abnormal pattern. In a fixation task, the instruction is to keep a steady gaze on a single unmoving target, which tends to be difficult for individuals with schizophrenia.
As expected, the researchers found that the performance of individuals with schizophrenia was abnormal compared to the healthy volunteer group on each of the eye tests. At right is an example of the differences, with the eye tracking of a schizophrenia case in red and a healthy control in blue.
The researchers then used several methods to model the data. The accuracy of each of the created algorithms was then tested by using eye test data from another group of cases and controls. Combining all the data, one of the models achieved 98.3% accuracy.
"It is encouraging to see the high sensitivity of this model for the diagnosis of schizophrenia. It will be interesting to see the extent to which this approach enables clinical investigators to distinguish people with schizophrenia from individuals with other psychiatric disorders," commented Dr. John Krystal, Editor of Biological Psychiatry.
Benson and St Clair have already started that work, stating, “We now have exciting unpublished data showing that patterns of eye movement abnormalities are specific to different psychiatric subgroups, another key requirement for diagnostic biomarkers. The next thing we want to know is when the abnormalities are first detectable and can they be used as disease markers for early intervention studies in major mental illness?”
"We are also keen to explore how best our findings can be developed for use in routine clinical practice," they added. Typical neuropsychological assessments are time-consuming, expensive, and require highly trained individuals to administer. In comparison, these eye tests are simple, cheap, and take only minutes to conduct. This means that a predictive model with such precision could potentially be incorporated in clinics and hospitals to aid physicians by augmenting traditional symptom-based diagnostic criteria.
(Source: alphagalileo.org)
New study sheds light on how and when vision evolved
Opsins, the light-sensitive proteins key to vision, may have evolved earlier and undergone fewer genetic changes than previously believed, according to a new study from the National University of Ireland Maynooth and the University of Bristol published in Proceedings of the National Academy of Sciences (PNAS) .
The study, which used computer modelling to provide a detailed picture of how and when opsins evolved, sheds light on the origin of sight in animals, including humans. The evolutionary origins of vision remain hotly debated, partly due to inconsistent reports of phylogenetic relationships among the earliest opsin-possessing animals.
Dr Davide Pisani of Bristol’s School of Earth Sciences and colleagues at NUI Maynooth performed a computational analysis to test every hypothesis of opsin evolution proposed to date. The analysis incorporated all available genomic information from all relevant animal lineages, including a newly sequenced group of sponges (Oscarella carmela) and the Cnidarians, a group of animals thought to have possessed the world’s earliest eyes.
Using this information, the researchers developed a timeline with an opsin ancestor common to all groups appearing some 700 million years ago. This opsin was considered ‘blind’ yet underwent key genetic changes over the span of 11 million years that conveyed the ability to detect light.
Dr Pisani said: “The great relevance of our study is that we traced the earliest origin of vision and we found that it originated only once in animals. This is an astonishing discovery because it implies that our study uncovered, in consequence, how and when vision evolved in humans.”
(Image credit: Roland Bircher)
Life without the Neurobeachin Protein
Scientists at Freie Universität, Universität Hohenheim, and Katholieke Universiteit Leuven Breed Fruit Flies for First Time without the Neurobeachin Protein and Facilitate Study of Nervous Diseases in Humans
In experiments on the brain of the fruit fly Drosophila, scientists at Freie Universität Berlin have advanced the research on brain function and diseases in humans. Neuroscientists in the Emmy Noether Junior Research Group “Biological Memory Systems” headed by Dr. Martin Schwärzel and based at Freie Universität succeeded in breeding fruit flies without the neurobeachin protein. Among other things, BEACH proteins affect the development and function of the brain in animals and humans. The results were published in the most recent issue of The Journal of Neuroscience. In the future such animal models could be of particular importance for the understanding of certain diseases in humans, such as autism. Scientists from the University of Hohenheim and the Belgian Katholieke Universiteit Leuven were also involved.
Up to now there were no animal models suitable for understanding the significance of neurobeachin proteins in the functioning of the nervous system, for example in memory formation. Mice that are lacking the neurobeachin protein die shortly after birth. Fruit flies, on the other hand, can be alive and well without neurobeachin. The scientists also found in experiments on the flies that neurobeachin has a function in learning as the flies exhibit characteristic learning disabilities due to the absence of the protein.
The flies were also found to have a number of other abnormalities with regard to the development and function of the nervous system. Through a “genetic rescue experiment,” the researchers were able to localize the distribution of these defects in the brain. The function of the lacking neurobeachin gene was reintroduced in certain areas of the nervous system. With this procedure, the researchers were able to show, among other things, that certain features of the neurobeachin protein in flies and mice are identical.
(Source: fu-berlin.de)
Solving Stem Cell Mysteries
The ability of embryonic stem cells to differentiate into different types of cells with different functions is regulated and maintained by a complex series of chemical interactions, which are not well understood. Learning more about this process could prove useful for stem cell-based therapies down the road. New research from a team led by Carnegie’s Yixian Zheng zeroes in on the process by which stem cells maintain their proper undifferentiated state. Their results are published in Cell October 26.
Embryonic stem cells go through a process called self-renewal, wherein they undergo multiple cycles of division while not differentiating into any other type of cells. This process is dependent on three protein networks, which guide both self-renewal and eventual differentiation. But the integration of these three networks has remained a mystery.
Using a combination of genetic, protein-oriented and physiological approaches involving mouse embryonic stem cells, the team—which also included current and former Carnegie scientists Junling Jia, Xiaobin Zheng, Junqi Zhang, Anying Zhang, and Hao Jiang—uncovered a mechanism that integrates all three networks involved in embryonic stem cell self-renewal and provide a critical missing link to understanding this process.
The key is a protein called Utf1. It serves three important roles. First, it balances between activating and deactivating the necessary genes to direct the cell toward differentiation. At the same time, it acts on messenger RNA that is the transcription product of the genes when they’re activated by tagging it for degradation, rather than allowing it to continue to serve its cellular function. Lastly, it blocks a genetic feedback loop that normally inhibits cellular proliferation, allowing it to occur in the rapid nature characteristic of embryonic stem cells.
People plus: is transhumanism the next stage in our evolution?
Inviting artificial intelligence into our bodies has appeal – but it also carries certain risks.
I have often wondered what it would be like to rid myself of a keyboard for data entry, and a computer screen for display. Some of my greatest moments of reflection are when I am in the car driving long distances, cooking in my kitchen, watching the kids play at the park, waiting for a doctor’s appointment or on a plane thousands of metres above sea level.
I have always been great at multitasking but at these times it is often not practical or convenient to be head down typing on a laptop, tablet or smartphone.
It would be much easier if I could just make a mental note to record an idea and have it recorded, there and then. And who wouldn’t want the ability to “jack into” all the world’s knowledge sources in an instant via a network?
Who wouldn’t want instant access to their life-pages filled with all those memorable occasions? Or even the ability to slow down the process of ageing, as long as living longer equated to living with mind and body fully intact, as outlined in the video.
Transhumanists would have us believe that these things are not only possible but inevitable. In short: we Homo sapiens may dictate the next stage of our evolution through our use of technology.
Evolution is actually pretty predictable
“Is evolution predictable? To a surprising extent the answer is ‘yes’,” says Princeton professor Peter Andolfatto.
New research by Andolfatto and colleagues published in the journal Science suggests that knowledge of a species’ genes—and how certain external conditions affect the proteins encoded by those genes—could be used to determine a predictable evolutionary pattern driven by outside factors.
Scientists could then pinpoint how the diversity of adaptations seen in the natural world developed even in distantly related animals.
The researchers carried out a survey of DNA sequences from 29 distantly related insect species, the largest sample of organisms yet examined for a single evolutionary trait. Fourteen of these species have evolved a nearly identical characteristic due to one external influence—they feed on plants that produce cardenolides, a class of steroid-like cardiotoxins that are a natural defense for plants such as milkweed and dogbane.
Though separated by 300 million years of evolution, these diverse insects—which include beetles, butterflies, and aphids—experienced changes to a key protein called sodium-potassium adenosine triphosphatase, or the sodium-potassium pump, which regulates a cell’s crucial sodium-to-potassium ratio.
Did bacteria spark evolution of multicellular life?
Bacteria have a bad rap as agents of disease, but scientists are increasingly discovering their many benefits, such as maintaining a healthy gut.
A new study now suggests that bacteria may also have helped kick off one of the key events in evolution: the leap from one-celled organisms to many-celled organisms, a development that eventually led to all animals, including humans.
Published this month in the inaugural edition of the new online journal eLife, the study by University of California, Berkeley, and Harvard Medical School scientists involves choanoflagellates (aka “choanos”), the closest living relatives of animals. These microscopic, one-celled organisms sport a long tail or flagellum, tentacles for grabbing food and are members of the ocean’s plankton community. As our closest living relative, choanos offer critical insights into the biology of their last common ancestor with animals, a unicellular or colonial organism that lived and died over 650 million years ago.
“Choanoflagellates evolved not long before the origin of animals and may help reveal how animals first evolved,” said senior author Nicole King, UC Berkeley associate professor of molecular and cell biology.
Higher-math skills entwined with lower-order magnitude sense
The ability to learn complex, symbolic math is a uniquely human trait, but it is intricately connected to a primitive sense of magnitude that is shared by many animals, finds a study to be published by the Proceedings of the National Academy of Sciences (PNAS).
"Our results clearly show that uniquely human branches of mathematics interface with an evolutionarily primitive general magnitude system," says lead author Stella Lourenco, a psychologist at Emory University. "We were able to show how variations in both advanced arithmetic and geometry skills specifically correlated with variations in our intuitive sense of magnitude."
Babies as young as six months can roughly distinguish between less and more, whether it’s for a number of objects, the size of objects, or the length of time they see the objects. This intuitive, non-verbal sense of magnitude, which may be innate, has also been demonstrated in non-human animals. When given a choice between a group of five bananas or two bananas, for example, monkeys will tend to take the bigger bunch.
"It’s obviously of adaptive value for all animals to be able to discriminate between less and more," Lourenco says. "The ability is widespread across the animal kingdom – fish, rodents and even insects show sensitivity to magnitude, such as the number of items in a set of objects."