1. Study explains why stress hormone can prevent disorders after exposure to traumatic event

    September 25, 2017 by Ashley

    From the Universitat Autònoma de Barcelona press release:

    People who have suffered from traffic accidents, war combat, terrorist attacks and exposure to other traumatic events have an increased likelihood of developing diseases. These diseases can be psychological and physical, such as heart problems and cancer. The current preventive treatments based on psychological support and drugs are effective in some cases. Unfortunately, these treatments do not work for many individuals. It is also known that the earlier the treatment starts the better to prevent future negative consequences.

    Researchers at the Institut de Neurociències of the Universitat Autònoma de Barcelona (INc-UAB, Spain) have discovered in a study with mice and humans that the Ppm1f (Protein phosphatase 1f) gene expression is one of the most highly regulated after exposure to traumatic stress. Moreover, Ppm1f is associated with posttraumatic stress disorder (PTSD), depression and anxiety. The main function of Ppm1f is to regulate the activity of the protein Camk2 (Calmodulin-dependent protein kinase 2), which is key in many processes of the human body such as memory, the heart’s functioning and the immune system.

    According to Dr. Raül Andero Galí, lead researcher in this study, “Once we discovered the relationship between the Ppm1f gene and different psychological disorders after exposure to traumatic stress, we wanted to find an effective drug to prevent these changes and its negative consequences on the brain.” Dr Andero is scientist at the INc-UAB. It was already known that dosing the stress hormone — a glucocorticoid — few hours after exposure to a traumatic event may decrease the likelihood of developing psychological disorders. Thus, the scientists administered the hormone to mice one hour after exposure to stress. “The results confirmed a decrease in the symptoms of anxiety and depression, and also that this effect is because the Ppm1f gene changes are prevented,” explains Dr. Eric Velasco, researcher at the INc-UAB and co-author of the study.

    “The apparent contradiction that the stress hormone decreases the likelihood of developing diseases after exposure to traumatic stress is one of the greatest paradoxes of current medicine” Andero says. “This study sheds light on this paradox and uncovers a way by which the stress hormone could prevent diseases, at least psychologically, through regulation of the Ppm1f gene” he adds.

    Until now, the stress hormone has been administered to people in very few cases. “Our discovery opens the door to a broader application and to the development of treatments aimed specifically at regulating this gene’s functions,” says Antonio Florido, researcher of the INc-UAB and also co-author of the paper.

    The study was carried out in collaboration with the universities of Harvard and Emory (United States). This work is published in Biological Psychiatry, one of the most important journals in Neuroscience. The UAB researchers are currently interested in collaborating with other laboratories and obtaining funding to continue the studies of Ppm1f associated with other disorders such as cardiovascular diseases and cancer in order to verify whether their results are comparable in other diseases and potentially prevent them.


  2. Popular bottle-breaking trick is giving insight to brain injuries

    by Ashley

    From the Brigham Young University press release:

    As many YouTube videos show, striking the top of a liquid-filled bottle can shatter the bottom. Now researchers are hoping to use new knowledge of that party trick to help fill a gap in something much more serious: brain research.

    A study by engineering professors from Brigham Young University, Utah State University and the Tokyo University of Agriculture and Technology details exactly what happens when a liquid at rest — like the water in a bottle — is suddenly put into motion. Using high-speed photography, the team shows how the swift acceleration causes small bubbles to form in the liquid and then rapidly collapse, releasing a destructive shockwave.

    The proper term for the phenomenon is called cavitation, a process well known to engineers for causing damage in pipes and marine propellers. The new study, published in the Proceedings of the National Academy of Sciences, details an alternative formula that more accurately predicts when cavitation will happen.

    While the finding has immediate implications for many industrial processes interrupted by cavitation-induced damage, there’s also growing evidence linking cavitation to brain trauma.

    “The brain is surrounded by fluid, and when you have impact, it’s possible you are experiencing cavitation within that fluid,” said study co-author Scott Thomson, associate professor of mechanical engineering at BYU.

    Fluid dynamics experts know how to predict when cavitation will occur in a fluid already in motion, but their formula doesn’t work so well when a resting fluid is rapidly accelerated. The new study fixes that problem by finalizing a new equation that considers a fluid’s depth and acceleration.

    For the brain, knowing this alternative cavitation formula could be used to better predict brain injuries caused by high-velocity impact. “And once we’re able to predict when that will happen, we can better design safety devices to help prevent serious brain damage,” Thomson said.

    Those safety devices could be for athletic applications, such as football helmets, or even military applications.

    “If a blast wave is above a certain magnitude, there may not be much we can do to prevent brain injury for a soldier,” said study author Tadd Truscott, associate professor of mechanical engineering at Utah State University. “But maybe a helmet can be developed to detect when that trauma has happened so a soldier can be removed from the front line and be saved from repeat exposure to blasts.”


  3. Study looks at neurological aspects of quitting cocaine addiction

    by Ashley

    From the Mount Sinai Hospital / Mount Sinai School of Medicine press release:

    Cocaine-addicted individuals say they find the drug much less enjoyable after years of use, but they have great difficulty quitting. A new brain imaging study led by researchers at the Icahn School of Medicine at Mount Sinai reveals why this might be so, as well as why a common psychological therapy may not work in addicted cocaine users.

    Their study, published September 5 in Addiction Biology, finds that chronic users have a “global impairment” in the ventromedial prefrontal cortex (VMPFC), an area of the brain that is linked to impulse and self-control, and is responsible for the kind of learning that assigns value to objects and behaviors.

    The Mount Sinai study investigated a specific type of learning called extinction — the process by which a new, affectively neutral, association replaces an old, affectively arousing association — to identify the neurobiological mechanism that underlies the persistence of drug seeking in addiction despite negative consequences and a reduction in the drug’s rewarding affects.

    To investigate these questions, the research team collected functional magnetic resonance imaging (fMRI) data on a three-phase classical conditioning paradigm in individuals with a history of chronic cocaine use and healthy control individuals without the drug habit. They found that in drug-addicted individuals, there was a VMPFC-mediated impairment in forming and maintaining new associations for stimuli that were previously, although no longer, predictive of both drug and non-drug related outcomes.

    “Our study data suggests that it will be hard for longtime cocaine users to unlearn what once was a positive experience if this ‘unlearning’ or new learning relies on this brain region to be effective,” says the study’s lead investigator, Anna Konova, PhD, who worked on the study while at the Icahn School of Medicine, but who is now a postdoctoral fellow at the Center for Neural Science at New York University.

    Extinction forms the basis for exposure therapy, which is often used to treat anxiety disorders like phobias.

    “There is a strong impetus for extinction-based therapy in addiction, but our findings highlight potential limitations of these existing therapies in their reliance on the VMPFC to achieve therapeutic benefits,” says the study’s senior investigator, Rita Z. Goldstein, PhD, who directs Mount Sinai’s Neuropsychoimaging of Addiction and Related Conditions research group.

    Dr. Goldstein is an international expert in the use of functional neuroimaging methods to examine the neurobiological basis of impaired cognitive and emotional functioning in human drug addiction and other disorders of self-control. Dr. Konova was a graduate student in Dr. Goldstein’s lab.

    A well-known example of the kind of learning that Dr. Konova and the research team studied in this study is the famous “Pavlov’s dog” experiment in which dogs learned to associate a food treat with the sound of a bell. Dogs soon started salivating when the bell rang. But if the bell rang enough times without being followed by the treat the salivation response of the dogs was reduced or extinguished.

    “The idea behind extinction learning as a therapeutic intervention is that a user can learn to substitute a relaxing thought — such as taking a nature stroll — for the thought of procuring cocaine when walking by their neighborhood park where they might have previously purchased or consumed the drug. By relying on these new associations, an addicted individual may be able to control their habit,” says Dr. Konova.

    Fear-based extinction learning is now widely used to treat anxiety, such as in phobias and post-traumatic stress disorder (PTSD). In this technique, a person is exposed to the thing that makes them afraid until the fear response to that thing (which is no longer associated with any real harm) is reduced and eventually extinguished, perhaps by forming a new, neutral or positive, association with their originally feared object or situation.

    While previous experiments have suggested VMPFC impairment in addicted individuals who have long used stimulants such as cocaine — a consistent finding is that the gray matter (a marker of neuronal morphological integrity) is altered in that brain area in these individuals — this is the first experiment to examine if these changes have implications for extinction learning in drug users and non-users using functional magnetic resonance imaging (fMRI) brain scans.

    The study participants — 18 chronic cocaine users and 15 control individuals from the same community — completed three rounds of learning over two days. The cocaine-using individuals had an average lifetime history of 17 years of cocaine use and currently used cocaine about twice a week. None were seeking treatment to stop.

    On the first day, while in the fMRI scanner, participants were shown, say, a colored square (a neutral cue) followed by a picture of a pleasant stimulus (such as a puppy), a different colored square this time followed by a drug-related picture (such as a crack pipe), and a third one followed by a picture of a household item. Like Pavlov’s dogs, the control individuals learned to anticipate the corresponding picture once they saw the specific square (anticipating the puppy, the drug item, or the household item). Their VMPFC also responded accordingly. They had learned the first association.

    Next, the groups were shown just the cues (squares) repeatedly and depending on the picture that had been linked to them before, their brain responses again responded accordingly: VMPFC responses now were not as high to the cues that predicted the picture of the puppy (a pleasant stimulus) and not as low as to the cues that predicted the crack pipe (an unpleasant stimulus). This was the first extinction phase, when extinction learning should occur. That is, new learning was taking place that the affectively charged pictures no longer followed the cues.

    Participants stayed overnight, and the next morning, they were shown the cues again. The extinction response was even more pronounced this time due to retention of some of the extinction association from the previous day.

    However, VMPFC signals in the cocaine-using group did not resemble that of the control group. Their data revealed that extinction learning did not engage the VMPFC to the same degree, which could result in failures in extinction learning, Dr. Konova says.

    “It may be possible to train other areas of the brain, such as the striatum, which we found did have normal responses in the drug users, to update the strong and well-established drug associations,” she says. “Or there could be ways to increase VMPFC function through cognitive retraining or pharmacologically. But our findings suggest that neither extinction learning for positive outcomes — anticipating seeing a cute puppy when this is no longer likely — or drug-related outcomes — anticipating seeing a crack pipe when this too is no longer likely — using that critical brain area will help longtime cocaine users quit.”

    “This really highlights the importance of neuroscience-informed treatment development for addiction, as this study and others like it can help speak to why some current approaches might fail or discover new, more effective ways to intervene,” says Dr. Goldstein.


  4. Study identifies biomarker for atypical development in infants at risk for developing autism

    September 24, 2017 by Ashley

    From the Columbia University Medical Center press release:

    New research from the Sackler Institute for Developmental Psychobiology at Columbia University Medical Center (CUMC) identifies a potential biomarker that predicts atypical development in 1- to 2-month-old infants at high versus low familial risk for developing autism spectrum disorders (ASD). The search for neurobiological markers that precede atypical trajectories is important in infants with a high risk for developing autism-related disorders because early recognition allows for early intervention and mitigation of difficulties later in life.

    Using data from National Database for Autism Research (NDAR), lead author Kristina Denisova, PhD, Assistant Professor of Psychiatry at CUMC and Fellow at the Sackler Institute, studied 71 high and low risk infants who underwent two functional Magnetic Resonance imaging brain scans either at 1-2 months or at 9-10 months: one during a resting period of sleep and a second while native language was presented to the infants. After extracting measures of head movements during the scans, the statistical characteristics of these movements were quantified.

    The study found that infants at high risk for developing ASD have elevated levels of “noise” and increased randomness in their spontaneous head movements during sleep, a pattern possibly suggestive of problems with sleep. In addition, 1- to 2-month-old high risk infants showed more similar signatures while listening to native language and while sleeping while low risk infants showed distinct signatures during the two conditions.

    Further, specific features of head movements during sleep at 1-2 months predicted future flatter (delayed) early learning developmental trajectories in the high-risk babies. The existence of generally atypical learning trajectories in the high risk group was verified in separate data sets from four representative high risk infant-sibling studies comprising a total of 1,445 infants with known ASD outcomes as children. These analyses showed that high risk infants — even those without ASD diagnoses — have significantly lower functioning in childhood relative to low risk infants. The current study reveals a possible way to predict which 1-2 months-old infants will show atypical developmental trajectories as toddlers.

    Dr. Denisova said, “The finding that head movement signatures are responsive to high context stimuli (native language speech) in low but not high risk infants is informative because it suggests that infants whose siblings were diagnosed with ASD are less attuned to evolutionarily important stimuli early in life.” She added that this response pattern may underlie atypical information processing in individuals with neurodevelopmental disorders.

    Dr. Jeremy Veenstra-VanderWeele, MD, an autism researcher who was not involved in this study, noted, “This study is a good example of how existing data can be mined for new insights. Additional work is needed to replicate the current findings and understand the underlying mechanisms, but this work suggests new ways to look at movement or motor function in infants at high risk of ASD.”


  5. Childhood maltreatment may change brain’s response to threat

    by Ashley

    From the Society for Neuroscience press release:

    Neural activity associated with defensive responses in humans shifts between two brain regions depending on the proximity of a threat, suggests neuroimaging data from two independent samples of adults in the Netherlands published in The Journal of Neuroscience. In one sample, the findings suggest that emotional abuse during childhood may shift the balance of activity between these regions.

    The amygdala and a closely related region called the bed nucleus of the stria terminalis (BNST) are both activated in response to a threat, but it is unclear how these regions orchestrate defensive responses in humans. Floris Klumpers and colleagues found that anticipation of an uncomfortable but harmless electrical shock was associated with increased activity in BNST, which is strongly connected with other brain regions that may be involved in deciding how to respond to a distant threat. In contrast, the shock itself was associated with increased activity in the amygdala, which maintains stronger connections with lower brain regions that may facilitate immediate and involuntary responses to acute danger, such as increased heart rate.

    Finally, the authors found that participants in one sample who reported greater childhood maltreatment (primarily emotional abuse and neglect rather than physical and sexual abuse) exhibited increased amygdala activity during shock anticipation. This finding shows how early life stress may impact an individual’s perception of distant threats.


  6. Study sheds new light on how brain operates like GPS

    September 23, 2017 by Ashley

    From the Florida State University press release:

    Every time you walk out of a building, you immediately see where you’re at and then step toward a destination. Whether you turn left, right or go straight ahead, you don’t even think about it. Simple, right?

    Not exactly. The brain performs a complex calculation that works a lot like the Global Positioning System.

    Florida State University’s Aaron Wilber, assistant professor of psychology and neuroscience, has discovered new insights into how the brain is organized to help a person navigate through life. His findings were published today in the September issue of the journal Neuron.

    “We have not had a clear understanding of what happens when you step out of a subway tunnel, take in your surroundings and have that moment where you instantly know where you are,” Wilber said. “Now we’re getting closer to understanding that.”

    Wilber wanted to get a clearer picture of how a person makes the transition from seeing a scene and then translating the image into a plan for navigation.

    The parietal cortex is the part of the brain that helps make that happen. It integrates information coming in from various senses and helps a person understand what action to take as a result. The response gets recorded as a memory with help from other parts of the brain, creating a “map” of the location that a person can recall to help get around from place to place.

    Then in the future a person can link that same view, or even just a part of it, to the brain’s map and know what action to take.

    Wilber discovered how the parietal cortex allows us to perform the appropriate action for a particular location.

    Lots of single cells in that region take in streams of sensory information to help a person get oriented, but those individual cells also cluster together in larger modules that work together. Those modules in the parietal cortex generate a physical response and, at the same time, are able to reconfigure themselves as a person learns and makes memories.

    “These different modules are talking to each other and seem to be changing their connections just like single cells change their connections,” Wilber said. “But now we’re talking about large groups of cells becoming wired up in different ways as you learn and remember how to make a series of actions as you go about your day-to-day business.”

    Wilber’s team was able to make recordings of various areas in a rat’s brain and found certain regions showed distinct patterns of activity, and those areas were associated with a particular action. Researchers converted those patterns of activity into graphical illustrations, which offered a visual model of brain activity patterns.

    The team then documented an identical sequence of patterns in certain areas of the brain every time the animal performed a series of actions. In fact, the illustrations were so accurate, researchers could identify the animal’s specific behavior just by looking at the brain activity patterns without ever seeing the actual physical action.

    Wilber continued making recordings when the rat slept and, based on the graphical waveforms, discovered the animal actually replayed the same actions in the brain during dreaming. But the dream sequence played out in fast forward at a rate about four times faster than real-life speed.

    “We think these fast-forward ‘dreams’ we observe in rats could explain why in humans when you dream and wake up, you think a lot more time passed than actually has because your dreams happen at high speed or fast forward,” Wilber said. “Maybe dreams happen in fast forward because that would make it easier to create new connections in your brain as you sleep.”

    As those new connections form, Wilber said, then the next time you go to the store you remember how to get there because your brain has linked your previous actions with certain places, such as turning right at a certain intersection.

    Wilber ultimately wants to understand how that process breaks down in people with Alzheimer’s disease or other neurological disorders. He recently received funding from the National Institutes of Health to pursue this research.


  7. Young binge drinkers show altered brain activity

    by Ashley

    From the Frontiers press release:

    Researchers have studied the brain activity of young binge-drinking college students in Spain, and found distinctive changes in brain activity, which may indicate delayed brain development and be an early sign of brain damage.

    For many students, college involves a lot of socializing at parties and at bars, and alcohol is a common factor in these social environments. Excessive alcohol use, in the form of binge drinking, is extremely common among college students, and one study has estimated that as many as one third of young North Americans and Europeans binge drink.

    So, what defines binge drinking? The National Institute of Alcohol Abuse and Alcoholism describes a binge as drinking five or more drinks for men and four or more for women within a two-hour period, and for many college students, these limits wouldn’t equate to a particularly heavy night. Previous research has linked binge drinking to a variety of negative consequences including neurocognitive deficits, poor academic performance, and risky sexual behavior.

    While numerous studies have shown that the brains of chronic alcoholics have altered brain activity, there is also evidence that bingeing can change adolescents’ brains. Eduardo López-Caneda, of the University of Minho in Portugal, investigates this phenomenon.

    “A number of studies have assessed the effects of binge drinking in young adults during different tasks involving cognitive processes such as attention or working memory,” says López-Caneda. “However, there are hardly any studies assessing if the brains of binge drinkers show differences when they are at rest, and not focused on a task.”

    In a recent study published in Frontiers in Behavioral Neuroscience, López-Caneda and colleagues set out to see if the resting brains of binge-drinking college students showed any differences compared with those of their non-bingeing counterparts.

    The researchers recruited first year college students from a university in Spain, and asked them to complete a questionnaire about their drinking habits. Students that had participated in at least one binge within the previous month were considered to be binge drinkers, whereas non-bingers had never binged before. By attaching electrodes to the students’ scalps, the scientists could assess electrical activity in various brain regions.

    Compared with the non-bingers, the binge drinkers demonstrated altered brain activity at rest. They showed significantly higher measurements of specific electrophysiological parameters, known as beta and theta oscillations, in brain regions called the right temporal lobe and bilateral occipital cortex.

    Surprisingly, previous studies have found very similar alterations in the brains of adult chronic alcoholics. While the young bingers in this study might occasionally consume alcohol to excess, they did not fit the criteria for alcoholism. So, what does this mean?

    The changes might indicate a decreased ability to respond to external stimuli and potential difficulties in information processing capacity in young binge drinkers, and may represent some of the first signs of alcohol-induced brain damage.

    The brains of adolescents are still developing, meaning that they might be more vulnerable to the effects of alcohol abuse. “These features might be down to the particularly harmful effects of alcohol on young brains that are still in development, perhaps by delaying neuromaturational processes,” says López-Caneda.

    The researchers stress that they need to carry out further studies to confirm if the features they have observed in these young binge drinkers are caused by their bingeing, and if their brain development might be impaired. However, the results suggest that bingeing has tangible effects on the young brain, comparable with some of those seen in chronic alcoholics. “It would be a positive outcome if educational and health institutions used these results to try to reduce alcohol consumption in risky drinkers,” says López-Caneda.


  8. Study suggests the bilingual brain calculates differently depending on the language used

    September 22, 2017 by Ashley

    From the University of Luxembourg press release:

    People can intuitively recognise small numbers up to four; however, when calculating they depend on the assistance of language. In this respect, the fascinating research question ensues: how do multilingual people solve arithmetical tasks presented to them in different languages of which they have a very good command? The question will gain in importance in the future, as an increasingly globalised job market and accelerated migration will mean that ever more people seek work and study outside of the linguistic area of their home countries.

    This question was investigated by a research team led by Dr Amandine Van Rinsveld and Professor Dr Christine Schiltz from the Cognitive Science and Assessment Institute (COSA) at the University of Luxembourg. For the purpose of the study, the researchers recruited subjects with Luxembourgish as their mother tongue, who successfully completed their schooling in the Grand Duchy of Luxembourg and continued their academic studies in francophone universities in Belgium. Thus, the study subjects mastered both the German and French languages perfectly. As Luxembourger students, they took maths classes in primary schools in German and then in secondary schools in French.

    In two separate test situations, the study participants had to solve very simple and a bit more complex addition tasks, both in German and French. In the tests it became evident that the subjects were able to solve simple addition tasks equally well in both languages. However, for complex addition in French, they required more time than with an identical task in German. Moreover, they made more errors when attempting to solve tasks in French.

    During the tests, functional magnetic resonance imaging (fMRI) was used to measure the brain activity of the subjects. This demonstrated that, depending on the language used, different brain regions were activated. With addition tasks in German, a small speech region in the left temporal lobe was activated. When solving complex calculatory tasks in French, additional parts of the subjects’ brains responsible for processing visual information, were involved. However, during the complex calculations in French, the subjects additionally fell back on figurative thinking. The experiments do not provide any evidence that the subjects translated the tasks they were confronted with from French into German, in order to solve the problem. While the test subjects were able to solve German tasks on the basis of the classic, familiar numerical-verbal brain areas, this system proved not to be sufficiently viable in the second language of instruction, in this case French. To solve the arithmetic tasks in French, the test subjects had to systematically fall back on other thought processes, not observed so far in monolingual persons.

    The study documents for the first time, with the help of brain activity measurements and imaging techniques, the demonstrable cognitive “extra effort” required for solving arithmetic tasks in the second language of instruction. The research results clearly show that calculatory processes are directly affected by language.


  9. Systems analysis points to links between Toxoplasma infection and common brain diseases

    by Ashley

    From the University of Chicago Medical Center press release:

    More than 2 billion people — nearly one out of every three humans on earth, including about 60 million people in the United States — have a lifelong infection with the brain-dwelling parasite Toxoplasma gondii.

    In the September 13, 2017, issue of Scientific Reports, 32 researchers from 16 institutions describe efforts to learn how infection with this parasite may alter, and in some cases amplify, several brain disorders, including epilepsy, Alzheimer’s and Parkinson’s diseases as well as some cancers.

    When a woman gets infected with T. gondii during pregnancy and passes the parasite on to her unborn child, the consequences can be profound, including devastating damage to the brain, nervous system and eyes.

    There is growing evidence, however, that acquiring this infection later in life may be far from harmless. So the researchers began looking for connections between this chronic but seemingly dormant infection and its potential to alter the course of common neurologic disorders.

    “We wanted to understand how this parasite, which lives in the brain, might contribute to and shed light on pathogenesis of other, brain diseases,” said Rima McLeod, MD, professor of ophthalmology & visual science and pediatrics and medical director of the Toxoplasmosis Center at the University of Chicago.

    “We suspect it involves multiple factors,” she said. “At the core is alignment of characteristics of the parasite itself, the genes it expresses in the infected brain, susceptibility genes that could limit the host’s ability to prevent infection, and genes that control susceptibility to other diseases present in the human host. Other factors may include pregnancy, stress, additional infections, and a deficient microbiome. We hypothesized that when there is confluence of these factors, disease may occur.”

    For more than a decade, researchers have noted subtle behavior manipulations associated with a latent T. gondii infection. Rats and mice that harbor this parasite, for example, lose their aversion to the smell of cat urine. This is perilous for a rodent, making it easier for cats to catch and eat them. But it benefits cats, who gain a meal, as well as the parasites, who gain a new host, who will distribute them widely into the environment. An acutely infected cat can excrete up to 500 million oocysts in a few weeks’ time. Even one oocyst, which can remain in soil or water for up to a year, is infectious.

    A more recent study found a similar connection involving primates. Infected chimpanzees lose their aversion to the scent of urine of their natural predator, leopards.

    The research team decided to search for similar effects in people. They focused on what they call the human “infectome” — plausible links between the parasite’s secreted proteins, expressed human microRNAs, the neural chemistry of the human host, and the multiple pathways that are perturbed by host-parasite interactions.

    Using data collected from the National Collaborative Chicago-Based Congenital Toxoplasmosis Study, which has diagnosed, treated and followed 246 congenitally infected persons and their families since 1981, they performed a “comprehensive systems analysis,” looking at a range of parasite-generated biomarkers and assessing their probable impact.

    Working with the J Craig Venter Institute and the Institute of Systems Biology Scientists, they looked at the effect of infections of primary neuronal stem cells from the human brain in tissue culture, focusing on gene expression and proteins perturbed. Part of the team, including Huan Ngo from Northwestern University, Hernan Lorenzi at the J Craig Venter Institute, Kai Wang and Taek-Kyun Kim at the Institute for Systems Biology and McLeod, integrated host genetics, proteomics, transcriptomics and circulating microRNA datasets to build a model of these effects on the human brain.

    Using what they called a “reconstruction and deconvolution,” approach, the researchers identified perturbed pathways associated with neurodegenerative diseases as well as connections between toxoplasmosis, human brain disorders and some cancers.

    They also found that:

    • Small regulatory biomarkers — bits of microRNA or proteins found in children with severe toxoplasmosis — matched those found in patients with neurodegenerative diseases like Alzheimer’s or Parkinson’s disease.
    • The parasite was able to manipulate 12 human olfactory receptors in ways that mimicked the cat-mouse or the chimp-leopard exchange.
    • Evidence that T. gondii could increase the risk of epilepsy, “possibly by altering GABAergic signaling.”
    • T. gondii infection was associated with a network of 1,178 human genes, many of which are modified in various cancers.

    “Our results provide insights into mechanisms whereby this parasite could cause these associated diseases under some circumstances,” the authors wrote. “This work provides a systems roadmap to design medicines and vaccines to repair and prevent neuropathological effects of T. gondii on the human brain.”

    “This study is a paradigm shifter,” said co-author Dennis Steinler, PhD, director of the Neuroscience and Aging Lab at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. “We now have to insert infectious disease into the equation of neurodegenerative diseases, epilepsy and neural cancers.”

    “At the same time,” he added, “we have to translate aspects of this study into preventive treatments that include everything from drugs to diet to life style, in order to delay disease onset and progression.”


  10. Study suggests teens’ ability to consider the intentions of others linked to structural changes in the brain

    September 21, 2017 by Ashley

    From the Dartmouth College press release:

    When it comes to the concept of fairness, teenagers’ ability to consider the intentions of others appears to be linked to structural changes underway in the brain, according to a Dartmouth-led study published by Scientific Reports. The study is the first to provide evidence linking structural changes with behavioral changes within this context. (See video: https://youtu.be/uLv5da5wvus.) Understanding the intentions of others is fundamental to human cooperation and how we exist as social beings.

    Understanding the intentions of others is fundamental to human cooperation and how we exist as social beings. Previous studies have demonstrated that certain areas of the social brain relating to how we care about others or “social inference,” continue to undergo cortical development until late adolescence. As demonstrated by the following time-lapse video, these changes include the thinning of the brain’s cortex, which likely reflect synaptic reorganization in how brain regions are connected and communicate with each other. The study is the first to provide evidence linking structural changes with behavioral changes in the brain within the context of fairness concerns.

    For the study, participants between nine and 23-years old took part in an ultimatum game based on the exchange of money. Proposers first selected between two different divisions of $10, and responders then decided whether to accept or reject the chosen division. Researchers evaluated how participants used two different cognitive strategies when making their decision using computational modeling, and then investigated how these processes correlated with measurements of participants’ cortical thickness, as obtained through magnetic resonance imaging (MRI).

    Younger players tended to want to minimize the difference in the division of the money, whereby everyone gets the same amount but as players became older, they were more inclined to consider the other player’s intentions. This shift from a simple rule-based egalitarian strategy to a more sophisticated strategy that considers both the other player’s intentions and notions of reciprocity, was observed during late adolescence. This gradual shift coincided with cortical thinning in the brain, specifically, in areas of the dorsomedial prefrontal cortex, which is involved with how we view others’ mental states, and posterior temporal cortex, which is involved in visual perception particularly in processing facial information.

    “This work provides converging evidence in line with other research that the computation of inferring intentions is processed in the dorsomedial prefrontal cortex,” said senior author Luke Chang, an assistant professor in the Department of Psychological and Brain Sciences and the director of the Computational Social Affective Neuroscience Laboratory (Cosan Lab) at Dartmouth. “We were surprised that this shift in preference for considering others’ intentions occurred so late in development. Of course, younger children can infer the intentions of others, but we see that this ability continues to be refined well into late adolescence. This finding has potential implications regarding how much autonomy this age group should be given when making important social and ethical decisions, such as purchasing weapons, going to war, and serving on juries,” added Chang.