- - - @archiveofbiognosis - Tumblr Blog

What the ability to “get the gist” says about your brain

Many who have a chronic traumatic brain injury (TBI) report struggling to solve problems, understand complex information and maintain friendships, despite scoring normally on cognitive tests. New research from the Center for BrainHealth at UT Dallas finds that a gist reasoning test, developed by clinicians and cognitive neuroscientists at the Center, is more sensitive than other traditional tests at identifying certain cognitive deficits.

The study, published in Journal of Applied Biobehavioral Research, suggests the gist reasoning test may be sensitive enough to help doctors and clinicians identify previously undiagnosed cognitive changes that could explain the daily life difficulties experienced by TBI patients and subsequently guide appropriate therapies.

The gist reasoning measure, called the Test of Strategic Learning, accurately identified 84.7 percent of chronic TBI cases, a much higher rate than more traditional tests that accurately identified TBI between 42.3 percent and 67.5 percent of the time.

“Being able to ‘get the gist’ is essential for many day-to-day activities such as engaging in conversation, understanding meanings that are implied but not explicitly stated, creating shopping lists and resolving conflicts with others,” said study lead author Dr. Asha Vas of Texas Woman’s University who was a postdoctoral fellow at the Center for BrainHealth at the time of the study. “The gist test requires multiple cognitive functions to work together.”

The study featured 70 participants ages 18 to 55, including 30 who had experienced a moderate to severe chronic traumatic brain injury at least one year ago. All the participants had similar socioeconomic status, educational backgrounds and IQ.

Researchers were blinded to the participant’s TBI status while administering four different tests that measure abstract thinking — the ability to understand the big picture, not just recount the details of a story or other complex information. Researchers used the results to predict which participants were in the TBI group and which were healthy controls.

During the cognitive tests, the majority of the TBI group easily recognized abstract or concrete information when given prompts in a yes-no format. But the TBI group performed much worse than controls on tests, including gist reasoning, that required deeper level processing of information with fewer or no prompts.

The gist reasoning test consists of three texts that vary in length (from 291 to 575 words) and complexity. The test requires the participant to provide a synopsis of each of the three texts.

Vas provided an example of what “getting the gist” means using Shakespeare’s play, Romeo and Juliet.

“There are no right or wrong answers. The test relies on your ability to derive meaning from important story details and arrive at a high-level summary: Two young lovers from rival families scheme to build a life together and it ends tragically. You integrate existing knowledge, such as the concept of love and sacrifice, to create a meaning from your perspective. Perhaps, in this case, ‘true love does not conquer all,’” she said.

Past studies have shown that higher scores on the gist reasoning test in individuals in chronic phases of TBI correlate to better ability to perform daily life functions.

“Perhaps, in the future, the gist reasoning test could be used as a tool to identify other cognitive impairments,” said Dr. Jeffrey Spence, study co-author and director of biostatistics at the Center for BrainHealth. “It may also have the potential to be used as a marker of cognitive changes in aging.”

currentsinbiology

How are long strands of DNA packed into tiny cells?

Scientists are a step closer to understanding how DNA, the molecules that carry all of our genetic information, is squeezed into every cell in the body. How DNA is “packaged” in cells influences the activity of our genes and our risk for disease.

DNA is a long, floppy molecule, and there’s more than three feet of it in every cell. Our DNA is housed in structures called chromosomes, which condense the DNA to fit into the cell’s tight quarters.

Scientists from the department of Biochemistry and Biophysics at the University of Rochester School of Medicine and Dentistry worked with colleagues in France and Japan to describe the first step of DNA packing in a cell. They provided the first-ever detailed picture of the most basic building block of chromosomes, known as the nucleosome, and found that a protein known as H1 (for linker histone H1) helps DNA become more compact and rigid within the nucleosome. In contrast, when H1 isn’t present, the DNA is loose and flexible.

The tight structure that H1 creates helps shield our DNA from various factors that can activate or “turn on” certain genes. Without H1, DNA is more accessible to factors that could trigger disease-causing genes.

Jan Bednar, Isabel Garcia-Saez, Ramachandran Boopathi, Amber R. Cutter, Gabor Papai, Anna Reymer, Sajad H. Syed, Imtiaz Nisar Lone, Ognyan Tonchev, Corinne Crucifix, Hervé Menoni, Christophe Papin, Dimitrios A. Skoufias, Hitoshi Kurumizaka, Richard Lavery, Ali Hamiche, Jeffrey J. Hayes, Patrick Schultz, Dimitar Angelov, Carlo Petosa, Stefan Dimitrov. Structure and Dynamics of a 197 bp Nucleosome in Complex with Linker Histone H1. Molecular Cell, 2017; 66 (3): 384 DOI: 10.1016/j.molcel.2017.04.012

mynotes4usmle

Disconnect Syndromes

neurosciencestuff

MRI modeling shows how pain is all in the brain

Pain is a signal of actual or potential damage to the body, so it is natural to think of it as a localized sensation: knee pain in the knee, back pain in the back and so on.

However, research has demonstrated that pain is an experience constructed in the brain. A knee doesn’t “feel” anything. Instead, it sends signals to the brain. Input from the body is important, but a person’s pain experience also depends on the brain’s interpretation of what the input signal means.

Scientists are just beginning to study these complex cerebral processes, and in a promising step forward, CU Boulder researchers have developed a functional MRI-based model that identifies brain activity patterns involved in varied pain experience, even when the input from the body is held constant.

“Pain is more than just a passive response to stimuli. The brain actively contributes to pain, constructing it through various neural systems,” said Choong-Wan Woo, lead author and a post-doctoral researcher in CU Boulder’s Institute of Cognitive Science when the research was completed. “Thus, we wanted to build a brain-based model to predict pain using variables beyond the painful stimuli.”

For the study, researchers began by aggregating data from six independent brain imaging studies, deliberately choosing those with differing methodologies. In all of the studies, participants had been exposed to several seconds’ worth of a painful stimulus and asked to rate their pain while inside an MRI scanner that recorded brain activity.

From the data, the researchers were able to identify common markers in the brain that were predictive of a participant’s different pain experiences when external stimuli are matched on intensity, resulting in fine-grained mapping of both positively correlated (“pro-pain”) and negatively correlated (“anti-pain”) brain sub-regions.

Comprising part of the new model, those markers several brain regions that are not classically considered important for pain. However, the regions — which include the ventromedial prefrontal cortex, nucleus accumbens, and hippocampus — are involved in the brain’s assessment of the meaning of painful and non-painful events alike.

The researchers named their telltale brain pattern the Stimulus Intensity Independent Pain Signature-1 (SIIPS1), a preliminary roadmap that can now be tested and refined in future studies.

“We now have a model that can be applied to other basic and clinical pain research in the field,” said Woo, who is now beginning an Assistant Professorship at Sungkyunkwan University in South Korea. “We deliberately added the number one to the name because we don’t think this is the only brain signature related to pain and expect that more will be developed.”

The SIIPS1 may provide researchers with a new understanding of chronic pain and hypersensitivity to pain, potentially paving the way for the development of clinical applications and more effective treatments.

“There is increasing evidence that chronic pain often involves changes in brain areas identified in our model,” said Tor Wager, a professor in CU Boulder’s Department of Psychology and Neuroscience and the study’s senior author. “The SIIPS1 provides a template for systematic evaluation of how these areas are altered in chronic pain. We hope that it will improve our understanding of chronic pain and lead to the development of new options for preventing and treating this complex disease.”

The study was published in the journal Nature Communications.

ucresearch

What bananas can tell us about radiation

Giant lizards destroying cities. Mushroom clouds. Three-eyed fish.

These are the things many people picture when they think of nuclear radiation. The general feeling is that any amount of radiation is too much radiation — but, in truth, we’re all exposed to radiation every day.

You can’t even eat a simple banana without getting exposed to radiation — a small fraction of the potassium in bananas naturally occurs as the radioactive potassium-40 isotope. But don’t spit up your smoothie: The dose of radiation from a single banana is very small, far less than the background radiation from simply living on Earth.

For a quick shot of perspective, it’s handy to look at the “banana equivalent dose” from common sources of radiation that people worry about:

Learn more about it at climate.universityofcalifornia.edu

mindblowingscience

We've learned so much already.

1. Lungs don’t just facilitate respiration - they also make blood. Mammalian lungs produce more than 10 million platelets (tiny blood cells) per hour, which equates to the majority of platelets circulating the body.

2. It is mathematically possible to build an actual time machine - what’s holding us back is finding materials that can physically bend the fabric of space-time.

3. Siberia has a colossal crater called the ‘doorway to the underworld’, and its permafrost is melting so fast, ancient forests are being exposed for the first time in 200,000 years.

4. The world’s first semi-synthetic organisms are living among us - scientists have given rise to new lifeforms using an expanded, six-letter genetic code.

5. Vantablack - the blackest material known to science - now comes in a handy ‘spray-on’ form and it’s the weirdest thing we’ve seen so far this year.

6. It’s official: time crystals are a new state of matter, and we now have an actual blueprint to create these “impossible” objects at will.

7. A brand new human organ has been classified, and it’s been hiding in plain sight this whole time. Everyone, meet your mesentery.

8. Carl Sagan was freakishly good at predicting the future - his disturbingly accurate description of a world where pseudoscience and scientific illiteracy reigns gave us all moment for pause.

9. A single giant neuron that wraps around the entire circumference of a mouse’s brain has been identified, and it appears to be linked to mammalian consciousness.

10. The world’s rarest and most ancient dog isn’t extinct after all - in fact, the outrageously handsome New Guinea highland wild dog appears to be thriving.

11. Your appendix might not be the useless evolutionary byproduct after all. Unlike your wisdom teeth, your appendix might actually be serving an important biological function - and one that our species isn’t ready to give up just yet.

12. After 130 years, we might have to completely redraw the dinosaur family tree, thanks to a previously unimportant cat-sized fossil from Scotland.

13. Polycystic ovary syndrome might actually start in the brain, not the ovaries.

14. Earth appears to have a whole new continent called Zealandia, which would wreak havoc on all those textbooks and atlases we’ve got lying around.

15. Humans have had a bigger impact on Earth’s geology than the infamous Great Oxidation Event 2.3 billion years ago, and now scientists are calling for a new geological epoch - the Anthropocene - to be officially recognised.

16. Turns out, narwhals - the precious unicorns of the sea - use their horns for hunting. But not how you’d think.

17. Human activity has literally changed the space surrounding our planet - decades of Very Low Frequency (VLF) radio communications have accidentally formed a protective, human-made bubble around Earth.

18. Farmers routinely feed red Skittles to their cattle, because it’s a cheap alternative to corn. ¯\_(ツ)_/¯

biomedicool

Penicillin

Penicillin is a widely used antibiotic prescribed to treat staphylococci and streptococci bacterial infections.

beta-lactam family

Gram-positive bacteria = thick cell walls containing high levels of peptidoglycan

gram-negative bacteria = thinner cell walls with low levels of peptidoglycan and surrounded by a lipopolysaccharide (LPS) layer that prevents antibiotic entry

penicillin is most effective against gram-positive bacteria where DD-transpeptidase activity is highest.

Examples of penicillins include:

amoxicillin

ampicillin

bacampicillin

oxacillin

penicillin

Mechanism(s)

Penicillin inhibits the bacterial enzyme transpeptidase, responsible for catalysing the final peptidoglycan crosslinking stage of bacterial cell wall synthesis.

Cells wall is weakened and cells swell as water enters and then burst (lysis)

Becomes permanently covalently bonded to the enzymes’s active site (irreversible)

Alternative theory: penicillin mimics D-Ala D-Ala

Or may act as an umbrella inhibitor

Resistance

production of beta-lactamase - destroys the beta-lactam ring of penicillin and makes it ineffective (eg Staphylococcus aureus - most are now resistant)

In response, synthetic penicillin that is resistant to beta-lactamase is in use including egdicloxacillin, oxacillin, nafcillin, and methicillin.

Some is resistant to methicillin - methicillin-resistant Staphylococcus aureus (MRSA).

Demonstrating blanket resistance to all beta-lactam antibiotics -extremely serious health risk.

fuckyeahfluiddynamics

In industry, tanks are often agitated or stirred to mix different elements. The goal is to create a laminar but chaotic flow field throughout the mixture. Introducing particles to such a system reveals that things are not quite as chaotic as they might seem. The photographs above show the pathlines of various large, glowing particles initially poured into the tank from above. Over time, the particles scatter off of structures in the mixed sections of the tank and end up trapped in vortex tubes that form above and below the agitator. Once trapped in the vortex tube, the particles follow helical paths inside the tube, creating patterns like those seen in the lower two photos. (Image and research credit: S. Wang et al., 1, 2, 3)

neurosciencenews

Trigger For Autoimmune Disease Identified

Researchers at National Jewish Health have identified a trigger for autoimmune diseases such as lupus, Crohn’s disease and multiple sclerosis.

The research is in Journal of Clinical Investigation. (full open access)

neurosciencestuff

Do dogs of all ages respond equally to dog-directed speech?

People tend to talk to dogs as though they are human babies. A new study in Proceedings of the Royal Society B shows that people speak more slowly and with a higher tone to dogs of all ages–both adults and puppies–and that puppies respond most readily to this dog-directed speech.

When talking to dogs, human adults use pet-directed speech similar to infant-directed speech (high pitch, slow tempo), which is known to engage infant attention and promote language learning. What about our dog companions? An international research team, led by Dr. Nicolas Mathevon of Hunter College, City University of New York (CUNY), and the University of Lyon/Saint-Etienne, has demonstrated that puppies are highly reactive to dog-directed speech but that older dogs do not react differentially to dog-directed speech compared to normal speech. Yet, human speakers employ dog-directed speech with dogs of all ages, suggesting that this register of speech is used to engage interaction with a non-speaking, rather than just a juvenile, listener.

Not only might people consciously or unconsciously wish to make themselves better understood through dog-directed speech, they may also be promoting word learning in dogs when doing so. It remains an open question whether puppies react innately to dog-directed speech and exactly why adult dogs showed a lack of preferential reactivity (at least in the absence of other communication cues) to dog-directed speech.

For now, people seem to consider dogs non-verbal companions and speak to them as they would human infants. We use similar strategies in other situations where we believe our listener may not fully understand us, such as when speaking to elderly people or linguistic foreigners.

currentsinbiology

Project to map human brain from womb to birth releases stunning images

A landmark project to map the wiring of the human brain from womb to birth has released thousands of images that will help scientists unravel how conditions such as autism, cerebral palsy and attention deficit disorders arise in the brain.

The first tranche of images come from 40 newborn babies who were scanned in their sleep to produce stunning high-resolution pictures of early brain anatomy and the intricate neural wiring that ferries some of the earliest signals around the organ.

The initial batch of brain scans are intended to give researchers a first chance to analyse the data and provide feedback to the senior scientists at King’s College London, Oxford University and Imperial College London who are leading the Developing Human Connectome Project, which is funded by €15m (£12.5m) from the EU.

Diffusion MRI showing connections in the developing brain. Photograph: The Developing Human Connectome Project

The images show the intricate neural wiring that ferries some of the earliest signals around the brain. Photograph: The Developing Human Connectome Project

3D reconstruction of the cortical surface and calculated features from a seven-month, eight-month and nine-month baby brain MRI. From top to bottom: white matter surface, cortical surface, inflated surface, parcellation into different structures, sulcal depth maps, mean curvature, cortical thickness and T1/T2 myelin maps. Photograph: The Developing Human Connectome Project

whatshappeningtothekids

Babies’ gazes suggest we are born understanding color

Scientists can’t just ask a newborn what it knows, so they use a trick known as “infant looking time” to figure out what’s in babies’ brains. The idea is that an infant’s gaze will linger on something unfamiliar for longer than something familiar, giving researchers a window into what babies expect—and what surprises them.

Applying this to color research, scientists led by Anna Franklin, a perception and cognition researcher at the University of Sussex in the United Kingdom, showed 179 infants aged 4-6 months 14 different swaths of color, each from a different part of the color wheel. Researchers showed one swath several times before displaying a hue from the next range over. If the infants looked at the new hue longer than the previous one, experimenters concluded that the babies considered it a different color.

The team found the infants reliably sorted the ranges of color into five categories: red, yellow, green, blue, and purple. Because these babies haven’t had much time to learn language—or even concepts—the researchers suspect these divisions of color are biologically innate, they report today in the Proceedings of the National Academy of Sciences.

wordsnquotes

‘no’ might make them angry but it will make you free.

Nayyirah Waheed, If No One Has Ever Told You, Your Freedom is More Important Than Their Anger (via kvtes)

oulfis

Today’s absurdist missive from Wikipedia: I was in fact there to learn something about the mathematical theorem, but was not prepared for the majesty of all of this.

currentsinbiology

Curb your immune enthusiasm

Normally when we think of viruses, from the common cold to HIV, we want to boost people’s immunity to fight them. But for scientists who develop therapeutic viruses (to, for example, target cancer cells or correct gene deficiencies) a more important question is: How do we keep people’s natural immune responses at bay? In these cases, an overenthusiastic immune response actually undermines the therapy.

Salk Institute researchers discovered that inhibiting a protein called phospholipid scramblase 1 (PLSCR1) controls the infected cell’s antiviral response and provides long-term protection from immune attack and excessive inflammation. The results, described in the January 19, 2017, issue of Neuron, hold promise both for virally delivered treatments and inflammatory conditions like infections; autoimmune disorders such as lupus; or neurodegenerative diseases such as Alzheimer’s disease.

Caption: Salk Institute researchers discovered that inhibiting a protein called phospholipid scramblase 1 (PLSCR1) controls the infected cell’s antiviral response and provides long-term protection from immune attack and excessive inflammation. Credit: Salk Institute

neurosciencestuff

(Image caption: Nucleus of a cell undergoing parthanatos. Credit: Yingfei Wang and I-Hsun Wu/Johns Hopkins Medicine)

Brain Cell ‘Executioner’ Identified

Despite their different triggers, the same molecular chain of events appears to be responsible for brain cell death from strokes, injuries and even such neurodegenerative diseases as Alzheimer’s. Now, researchers at Johns Hopkins say they have pinpointed the protein at the end of that chain of events, one that delivers the fatal strike by carving up a cell’s DNA. The find, they say, potentially opens up a new avenue for the development of drugs to prevent, stop or weaken the process.

A report on the research appears in the Oct. 7 issue of the journal Science.

The new experiments, conducted in laboratory-grown cells, build on earlier work by research partners Ted Dawson, M.D., Ph.D., now director of the Institute for Cell Engineering at the Johns Hopkins University School of Medicine, and Valina Dawson, Ph.D., professor of neurology. Their research groups found that despite their very different causes and symptoms, injury, stroke, Alzheimer’s disease, Parkinson’s disease and the rare, fatal genetic disorder Huntington’s disease have a shared mechanism of a distinct form of “programmed” brain cell death they named parthanatos after the personification of death in Greek mythology and PARP, an enzyme involved in the process.

“I can’t overemphasize what an important form of cell death it is; it plays a role in almost all forms of cellular injury,” Ted Dawson says. His and Valina Dawson’s research groups have spent years delineating each of the links in the parthanatos chain of events and the roles of the proteins involved.

The current study, they say, has completed the chain. From previous studies, the researchers knew that when a protein called mitochondrial apoptosis-inducing factor, or AIF, leaves its usual place in the energy-producing mitochondria of the cell and moves to the nucleus, it sparks the carving up of the genome housed in the nucleus and leads to cell death.

But AIF itself, they say, can’t cut DNA. So then-postdoctoral fellow Yingfei Wang, Ph.D., now an assistant professor at the University of Texas Southwestern Medical Center, used a protein chip to screen thousands of human proteins to find those that interacted most strongly with AIF. Working with the 160 candidates she uncovered, she then used custom molecules called small interfering RNAs to stop each of those proteins’ manufacture, one by one, in lab-grown human cells to see if doing so would prevent cell death.

One of the 160 proteins, known as macrophage migration inhibitory factor (MIF), was a winner. “We found that AIF binds to MIF and carries it into the nucleus, where MIF chops up DNA,” Ted Dawson says. “We think that’s the final execution step in parthanatos.”

The group reports that in work to be published, it also identified a few chemical compounds that block MIF’s action in the lab-grown cells, protecting them from parthanatos. Dawson says they plan to test these in animals, and modify them to maximize their safety and effectiveness.

He cautions that while parthanatos is known to cause cell death in many brain conditions, MIF’s ability to chop up DNA has so far only been definitively linked with stroke — when the MIF gene was disabled in mice, the damage caused by a stroke was dramatically reduced. “We’re interested in finding out whether MIF is also involved in Parkinson’s, Alzheimer’s and other neurodegenerative diseases,” he says. If so, and if an inhibitor of MIF proves successful in testing, it could have implications for treating many conditions, he says.

fuckyeahfluiddynamics

These strange flower-like formations appear in a former limestone quarry in France. The black that you see is bitumen, or asphalt. These dendritic structures appear in spots where the rock has fractured. Originally, two rock faces met here, with a thin layer of bitumen glued between them. As one face pulled away, air began to seep into the space between, slowly injecting itself into the more viscous bitumen. Just as we observe in the laboratory, the air and bitumen formed viscous fingers, creating a classic pattern known as the Saffman-Taylor instability. It’s so cool to see an example of this in nature! You can see more photos of the formations here. (Image credit: P. Thomas)

fuckyeahneuroscience

These look like cerebellar structures!

Trending Blogs

Recently Viewed Blogs

- - -