Brain Structure, Height and Cognitive Ability Linked

MedicalResearch.com Interview with:

Dr. Eero Vuoksimaa PhD Institute for Molecular Medicine University of Helsinski Finland

Dr. Vuoksimaa

Dr. Eero Vuoksimaa PhD
Institute for Molecular Medicine
University of Helsinski
Finland

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: There are many previous reports indicating a positive association between height and cognitive ability but the underlying mechanisms behind this correlation are not well known. We used a mediation model to test if this association is explained by brain size as measured with cortical grey matter size.

We found that total cortical surface mediated the relationship between height and cognitive ability.

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Prenatal Exposure to SSRIs May Be Linked to Changes in Infant Brain Development

MedicalResearch.com Interview with:

Jiook Cha, PhD Assistant Professor Division of Child and Adolescent Psychiatry  Columbia University Medical Center  New York, NY 10032

Dr. Jiook Cha

Jiook Cha, PhD
Assistant Professor
Division of Child and Adolescent Psychiatry
Columbia University Medical Center
New York, NY 10032

MedicalResearch.com: What did we already know about the connection between maternal SSRI use during pregnancy and infant brain development, and how do the current study findings add to our understanding? What’s new/surprising here and why does it matter for mothers and babies?

Response: Prior studies have shown mixed results in terms of the associations between maternal SRI use during pregnancy and offspring’s brain and cognitive development. Neurobiological studies with animal models suggest that SSRI use perturbs serotonin signaling and that this has important effects on cognitive development (a study conducted an author of this paper, Jay Gingrich, MD, PhD: Ansorge et al., 2004, Science). The human literature has been more mixed in terms of the associations of prenatal exposure to SSRI with brain and cognitive development.

In our study, we used neonatal brain imaging because this is a direct, non-invasive method to test associations between SSRI use and brain development at an early developmental stage, limiting the effects of the post-natal environment. In our study, we had two different control groups, that is, a non-depressed SSRI-free group (healthy controls), and depressed but SSRI-free (SSRI controls) group. Also, in our study we used rigorous imaging analytics that significantly improve the quantitative nature of MR-derived signals from the brain structure using two of the nation’s fastest supercomputers (Argonne National Laboratory and Texas Advanced Computing Center) and allows robust reconstruction of brain’s grey and white matter structure in the infants’ brains.

We report a significant association of prenatal exposure to SSRI with a volume increases within many brain areas, including the amygdala and insula cortex, and an increase in white matter connection strength between the amygdala and insular cortex. We were surprised by the magnitude of the effects (or the statistical effect size), compared with other brain imaging studies in psychiatry with children or adults’ brains. Importantly, it should be noted that our estimates of brain structure are still experimental and for research-purpose only. This means that our data need to be replicated and rigorously tested against confounders in order to make a firm conclusion. While our study suggests a “potential” association between prenatal exposure to SSRI and a change in fetal or infant brain development, we still need more research. 

tracts_in_the_brain

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Which Brain Circuits Determine Maternal Behavior?

MedicalResearch.com Interview with:
“Mother and Child” by Mary Cassatt (American, Pittsburgh, Pennsylvania 1844–1926 Le Mesnil-Théribus, Oise) via The Metropolitan Museum of Art is licensed under CC0 1.0Yi-Ya Fang

NYU School of Medicine
Dayu Lin, PhD
Neuroscience Institute, New York University Langone School of Medicine,  Department of Psychiatry,
Center for Neural Science
New York, NY

Response: Maternal behaviors are essential for survival of offspring across mammalian species. In rodents, mothers show several characteristic pup caring behaviors including grooming pups, crouching over pups and approaching and retrieving pups. Decades of research has been trying to understand how the neural circuit is wired to generate these elaborate maternal behaviors. Medial preoptic area (MPOA), which is located at anterior part of hypothalamus, has been indicated to be important for maternal behaviors. Many studies consistently found deficits in maternal behaviors after damaging the MPOA. To dissect the maternal circuits in the brain, we looked into the properties of the Esr1+ cells.

In this study, we identify estrogen receptor α (Esr1) expressing cells in MPOA as key mediators of pup approach and retrieval. We focused on Esr1 (Esr1) expressing cells in the MPOA since estrogen has been shown to facilitate maternal behaviors, presumably through its action of estrogen sensing cells. We found that reversible inactivation of MPOA Esr1+ cells impairs maternal behaviors whereas optogenetic activation of MPOA Esr1+ cells induces immediate pup retrieval. Additionally, we found that MPOA Esr1+ cells are preferentially activated during maternal behaviors, and the cell responses changed across reproductive states. Tracing studies revealed that MPOA Esr1+ cells project strongly to ventral tegmental area (VTA), a region that has been indicated in motivation and reward. Specifically, MPOA Esr1+ cells provide strong inhibitory inputs preferentially to the GABAergic cells in the VTA, which in turn could disinhibit the dopaminergic cells.  VTA dopaminergic cells are highly activated during maternal behaviors.

Altogether, our study provides new insight into the neural circuit that generates maternal behaviors.

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How Does the Brain Switch Between Automatic and Controlled Decision Making?

MedicalResearch.com Interview with:
Ksenija Marinkovic and Lauren Beaton

Psychology Department – College of Sciences Spatio-Temporal Brain Imaging Lab Center for Clinical and Cognitive Neuroscience
San Diego State University
San Diego CA

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: In general, we subjectively perceive our actions to be under our deliberate and voluntary control. However, our results are consistent with other accruing evidence suggesting that a large portion of our behavior is automatic and not accessible to conscious experience. The automatic processing primarily underlies predictable daily routines when we seem to be on an “auto-pilot”. In contrast, situations that are ambiguous or that evoke incompatible response tendencies engage cognitive control which allows conscious override of the preplanned actions and results in flexible behavior. Our study used a multimodal imaging approach that combines perfect time sensitivity of magnetoencephalography (MEG) with structural magnetic resonance imaging (MRI) to investigate spatio-temporal stages of the seamless interplay between automatic and controlled processing. MEG is a highly sensitive method that records magnetic fields generated by the brain’s neural activity in real time.

Young, healthy, participants performed a version of the Eriksen Flanker task, which presents two colored squares on either side of a centrally presented target square that appears after a short delay. Participants are instructed to press a button corresponding to the color of the target square in the middle and to pay no attention to the flankers. Although participants know that the flankers are irrelevant, they are unable to disregard them deliberately. Instead, flankers trigger an automatic preparation to respond. This is particularly apparent on mismatch trials on which the flanker color is misleading and it activates the wrong hand. Target appearance overrides the initial automatic response as the response plan is switched to the other hand to make a correct response. This process reflects recruitment of cognitive control or the decision-making capacity which includes a range of functions such monitoring contextual demands, selecting the correct response, and suppressing an automatic but irrelevant action.

Our multimodal MEG imaging method has allowed us to track the neural response as the brain prepares an incorrect response to flankers and then “switches” motor preparation between hemispheres. This approach makes it possible to investigate the interplay between automatic and controlled processing and dissect decision making as it unfolds.

The addition of a moderate dose of alcohol dysregulates this frontal network involved in motor decision making, which decreases accuracy when response conflict is present and lowers neural activity reflecting cognitive control. Related to this overall decrease, and of clinical importance, is the reduced ability to employ cognitive control to refrain from drinking excessively. However, the underlying patterns of response-switching were preserved under alcohol, suggesting that alcohol primarily induces deficits upstream during decision making and not during executing motor commands.  Continue reading

Shifting Attention Causes Momentary Brain Freeze

MedicalResearch.com Interview with:

Alex Maier, PhD Assistant Professor of Psychology Assistant Professor of Ophthalmology and Visual Science Vanderbilt University

Dr. Maier

Alex Maier, PhD
Assistant Professor of Psychology
Assistant Professor of Ophthalmology and Visual Science
Vanderbilt University

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: We were interested in finding out about how the brain shifts attention from one location to another. We knew that when we attend a certain location, brain activity increases in a specific way. This increase in activity is how we perform better when we use attention. What we knew less about is what happens when attention moves between locations.

To our surprise, we found that there is a brief moment in between these attentional enhancements, while attention moves from one location to another, where the brain does the complete opposite and decreases its activity. Shifting attention thus has a brief negative effect on our brain’s ability to process information about the world around us.

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Adherence to HIV Treatment May Protect Brain From Further Injury

MedicalResearch.com Interview with:

Ryan Sanford

Ryan Sanford

Ryan Sanford, MEng
Department of Neurology and Neurosurgery
Montreal Neurological Institute
McGill University, Montréal, Québec, Canada
 

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: With the introduction of combination antiretroviral therapy (cART) the outlook for HIV+ individuals has dramatically shifted from a fatal disease to a chronic manageable condition. However, HIV-associated neurocognitive disorders are still prevalent. The etiology of this dysfunction remains unknown. Previous work has reported progressive brain atrophy in HIV+ individuals with advanced disease and poor viral suppression, but it is unclear whether stable treatment and effective viral suppression can mitigate the progression of brain atrophy. To examine this issue, we followed well-treated HIV+ individuals with good viral suppression and well-matched controls, and assessed whether ongoing brain atrophy occurs over time.

The main finding in this study was the HIV+ participants had reduced brain volumes and poorer cognitive performance compared to the control group, but the changes in brain volumes and cognitive performance were similar between the groups.

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A Split Brain Has Two Perceptions But One Mind

MedicalResearch.com Interview with:

DR. Y. (YAÏR) PINTO Faculty of Social and Behavioural Sciences Programme group Brain and Cognition UvA

Dr. Pinto

DR. Y. (YAÏR) PINTO
Faculty of Social and Behavioural Sciences
Programme group Brain and Cognition
UvA

MedicalResearch.com: What is the background for this study?

Response: I’ve done research into patients in whom the corpus callosum was entirely removed surgically, at an adult age, to relieve epileptic seizures. The removal of the corpus callosum all but eliminates communication between both cerebral hemispheres. Therefore these patients are referred to as split-brain patients.

The canonical view of these patients is that their consciousness is split as well. That is, the notion, which is found in many textbooks and reviews, is that in a split-brain patient each hemisphere is an conscious agent, independent of the other hemisphere.

This notion is mainly based on the following key observation. When an image is presented to the left visual field, the patient indicates verbally, and with his right hand, that he saw nothing. Yet, with his left hand he indicates that he did see the object! Conversely, if a stimulus appears in his right visual field, he will indicate awareness of this stimulus when he responds verbally or with his right, yet with his left hand he will report that he saw nothing. This exactly fits the notion that in a split-brain patient the two separated hemispheres each become an independent conscious agent. The left hemisphere perceives the right visual field, controls language and the right side of the body. The right hemisphere experiences the left visual field and controls the left hand. This, and other discoveries on split-brain patients, earned Roger Sperry the nobel-prize in Medicine in 1981.

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Neuroanatomy Accounts for Age-Related Changes in Risk Preferences.

MedicalResearch.com Interview with:
Ifat Levy, PhD

Associate Professor
Comparative Med and Neuroscience
Yale School of Medicine

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: The proportion of older adults in the population is rapidly rising. These older adults need to make many important decisions, including medical and financial ones, and therefore understanding age-related changes in decision making is of high importance. Prior research has shown that older adults tend to be more risk averse than their younger counterparts when making choices between sure gains and lotteries. For example, asked to choose between receiving $5 for sure and playing a lottery with 50% of gaining $12 (but also 50% of gaining nothing), older adults are more likely than young adults to prefer the safe $5. We were interested in understanding the neurobiological mechanisms that are involved in these age-related shifts in preferences.

An earlier study that we have conducted in young adults provided a clue. In that study, we measured the risk preference of each participant (based on a series of choices they made between safe and risky options), and also used MRI to obtain a 3D image of their brain. Comparing the behavioral and anatomical measures, we found an association between individual risk preferences and the gray-matter volume of a particular brain area, known as “right posterior parietal cortex” (rPPC), which is located at the back of the right side of the brain. Participants with more gray matter in that brain area were, on average, more tolerant of risk (or less risk averse).

This suggested a very interesting possibility – that perhaps the increase in risk aversion observed in older adults is linked to the thinning of gray matter which is also observed in elders. In the current study we set out to test this hypothesis, by measuring risk preference and gray matter density in a group of 52 participants between the ages of 18 and 88. We found that, as expected, older participants were more risk averse than younger ones, and also had less gray matter in their rPPC. We also replicated our previous finding – that less gray matter was associated with higher risk aversion. The critical finding, however, was that the gray matter volume was a better predictor of increased risk aversion than age itself.  Essentially, if both age and the gray matter volume of rPPC were used in the same statistical model, rPPC volume predicted risk preferences, while age did not. Moreover, the predictive power was specific to the rPPC – when we added the total gray matter volume to the model, it did not show such predictive power.

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Non-Invasive Interface Allows Subjects To Control Objects With Just Thoughts

MedicalResearch.com Interview with:

Bin He, Ph.D. Director, Institute for Engineering in Medicine Director, Center for Neuroengineering Distinguished McKnight University Professor of Biomedical Engineering Medtronic-Bakken Endowed Chair for Engineering in Medicine University of Minnesota, Minneapolis, MN 55455

Dr. Bin He

Bin He, Ph.D.
Director, Institute for Engineering in Medicine
Director, Center for Neuroengineering
Distinguished McKnight University Professor of Biomedical Engineering
Medtronic-Bakken Endowed Chair for Engineering in Medicine
University of Minnesota, Minneapolis, MN 55455

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: This work is aimed at developing a noninvasive brains-computer interface to allow disabled patients to control their environment by just thinking about it.

We found 8 human subjects were able to accomplish 3D reach and grasp tasks without using any muscle activities but just thinking about it.

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Active Memory Blocker Prevents Experiences During Sleep From Being Remembered

MedicalResearch.com Interview with:
Roi Levy
The Leslie and Susan Gonda (Goldschmied) Multidisciplinary Brain Research Center,
The Mina and Everard Goodman Faculty of Life Sciences
Bar Ilan University
Ramat Gan, Israel

MedicalResearch.com: What is the background for this study?

Response: Long-term memory after an experience takes many hours to be reach its final form. During the consolidation period, the nascent memory is labile: the consolidation can be interrupted by new experiences, or new experiences that are too insignificant to be remembered can capture the consolidation process, and thereby be remembered.

To avoid potentially maladaptive interactions between a new experience and consolidation, a major portion of the consolidation is deferred to the time in which we sleep, when new experiences are unlikely. For over 100 years, studies have demonstrated that sleep improves memory formation. More recent studies have shown that consolidation occurs during sleep, and that consolidation depends on the synthesis of products that support memory formation. Consolidation is unlikely to be shut off immediately when we are awakened from sleep. At this time, even a transient experience could capture the consolidation, leading to a long-lasting memory of an event that should not be remembered, or could interfere with the consolidation. We have identified a mechanism that prevents long-term memories from being formed by experiences that occur when awakened from sleep.

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God Activates Reward Centers In Brain

MedicalResearch.com Interview with:

Jeffrey S. Anderson, MD, PhD Director the fMRI Neurosurgical Mapping Service Principal Investigator for the Utah Functional Neuroimaging Laboratory University of Utah

Dr. Jeffrey S. Anderson

Jeffrey S. Anderson, MD, PhD
Director the fMRI Neurosurgical Mapping Service
Principal Investigator for the Utah Functional Neuroimaging Laboratory
University of Utah

MedicalResearch.com: What is your study about?

Response: Billions of people find meaning in life and make choices based on religious and spiritual experiences. These experiences range from epiphanies that change the lives of celebrated mystics to subtle feelings of peace and joy in the lives of neighbors, friends, or family members that are interpreted as spiritual, divine, or transcendent.

Astonishingly, with all we understand about the brain, we still know very little about how the brain participates in these experiences. We set out to answer what brain networks are involved in representing spiritual feelings in one group of people, devout Mormons.
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How Does Consciousness Emerge From Brain’s Neural Network?

MedicalResearch.com Interview with:

Researchers suggest that there are unique areas in the brain’s neuronal network that can serve as the conscious complex of the brain, enabling conscious activity

Researchers suggest that there are unique areas in the brain’s neuronal network that can serve as the conscious complex of the brain, enabling conscious activity. Credit: Nir Lahav,     Eti Ben Simon

Nir Lahav
Physics Department
Bar-Ilan University in Israel

MedicalResearch.com: What is the background for this study?

Response: Our brain is a very complex network, with approximately 100 billion neurons and 100 trillion synapses between the neurons. The question is how can we cope with this enormous complexity?

Ultimately, scientists seek to understand how a global phenomenon such as consciousness can emerge from our neuronal network.

We used network theory in order to cope with this complexity and to determine how the structure of the human cortical network can support complex data integration and conscious activity.

Previous studies have shown that the human cortex is a network with small world properties, which means that it has many local structures and some shortcuts from global structures which connect faraway areas (similar to the difference between local buses and cross-country trains). The cortex also has many hubs, which are nodes that have a high number of links (like central stations), that are also strongly interconnected between themselves, making it easy to travel between the brain’s information highways.But in order to examine how the structure of the network can support global emerging phenomena, like consciousness, we need to look not only in the different nodes. We need to check global areas with lots of nodes. That’s why we applied a network analysis called k-shell decomposition. This analysis takes into account the connectivity profile of each node making it easy to uncover different neighborhoods of connections in the cortical network, we called shells. The most connected neighborhood in the network is termed the network’s nucleus. until today scientists were only interested in the network’s nucleus, but we found that these different shells can hold important information about how the brain integrates information from the local levels of each node to the entire global network. For the first time we can build a comprehensive topological model of our cortex.

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Cannabis Exposure During Pregnancy Linked To Changes in Brain Development in Childhood

MedicalResearch.com Interview with:
Dr. Hanan El Marroun, PhD
Assistant Professor
Department of Child and Adolescent Psychiatry, Department of Epidemiology
The Generation R Study
Erasmus, The Netherlands

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: The background for the study is that little is known about the potential long-term effects of cannabis exposure during pregnancy on child development.

The main findings are the prenatal cannabis exposure was associated with differences in cortical thickness in childhood.

MedicalResearch.com: What should readers take away from your report?

Response: That our findings suggest an association between prenatal cannabis exposure and cortical thickness in children. However, the results must be carefully interpreted, as there may be other factors involved that we did not take into account. Therefore, further research is needed to explore the causal nature of this association.

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Brain Circuits Limit Our Ability To Multitask

Michael M. Halassa, MD, PhD, Assistant professor Departments of Psychiatry and Neuroscience and Physiology The Neuroscience Institute Depts. of Psychitatry Langone Medical Center New York, NY 10016

Dr. Michael Halassa

MedicalResearch.com Interview with:
Michael M. Halassa, MD, PhD, Assistant professor

Departments of Psychiatry and Neuroscience and Physiology
The Neuroscience Institute Depts. of Psychitatry
Langone Medical Center
New York, NY 10016

Medical Research: What is the background for this study? What are the main findings?

Dr. Halassa:  Attention is a vital aspect of our daily life and our minds are not merely a reflection of the outside world, but rather a result of careful selection of inputs that are relevant. In fact, if we indiscriminately open up our senses to what’s out there, we would be totally overwhelmed. Selecting relevant inputs and suppressing distractors is what we call attention, and as humans we are able to attend in a highly intentional manner. Meaning, we choose what to pay attention to, and we do so based on context. If you’re driving and getting directions from your GPS, you’ll be intentionally splitting your attention between your vision and hearing. Now, in one context, you might have just updated the GPS software, so you know it’s reliable; this would allow you to intentionally pay attention more to the voice coming from the GPS. In another context, the GPS software may be outdated making voice instructions unreliable. This context would prompt you to direct your attention more towards using visual navigation cues and less to the GPS voice. How the brain intentionally and dynamically directs attention based context is unknown.

The main strength of our study is that we were able to study context-dependent attention in mice. Mice are unique models because they provide genetic tools to study brain circuits. Meaning, we can turn circuits on and off very precisely in the mouse, and in a way we cannot do in other experimental animals. The inability to do these types of manipulations has been the major roadblock for progress in understanding what brain circuits mediate attention and its intentional allocation.

Because we couldn’t train mice to drive and listen to the GPS, we decided to do something much simpler. Based on context (the type of background noise in the experimental enclosure), a mouse had to select between conflicting visual and auditory stimuli in order to retrieve a milk reward. Mice love milk; it turns out, and will work tirelessly to do well on getting it. Each trial, the mouse is told ‘you need to pick the light flash’ or ‘you need to pick the auditory sweep’; these stimuli appeared on either side of the mouse randomly so the animal really had to pay attention in order to get its reward. It also had to take the context into account. We found that mice did this task, and as humans would do, they were reliant on the prefrontal cortex for determining the appropriate context. The major finding was that the prefrontal cortex changed the sensitivity of the brain to incoming stimuli (meaning, made the visual stimulus brighter when the mouse cared about vision and made the auditory stimulus louder when the mouse cared about hearing), by influencing activity in the thalamus. The thalamus is the major early relay station in the brain. The prefrontal cortex does that by instructing the brain’s switchboard, known as the thalamic reticular nucleus (TRN) to control how much visual or auditory information the thalamus was letting through. So in a sense, we discovered that executive function, represented by the prefrontal cortex, can talk to ‘attentional filters’ in the thalamus to determine what ultimately is selected from the outside environment to build our internal world.
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Cooked Carbohydrates May Have Boosted Human Brain Growth Over Time

Karen Hardy  ICREA, Catalan Institution for Research and Advanced Studies Departament de Prehistòria Facultat de Filosofia i Lletres Universitat Autònoma de Barcelona Barcelona, SpainMedicalResearch.com Interview with:
Dr. Karen Hardy 
ICREA, Catalan Institution for Research and Advanced Studies
Departament de Prehistòria
Facultat de Filosofia i Lletres
Universitat Autònoma de Barcelona
Barcelona, Spain

 

MedicalResearch: What is the background for this study? What are the main findings?

Dr. Hardy: There continues to be little clear agreement on what quantitatively constitutes a healthy diet. The global increase in the incidence of obesity and diet-related metabolic diseases have intensified interest in ancestral or “Palaeolithic” diets as it is clear that to a first order of approximation our physiology should be optimized to the diet that we have experienced during our evolutionary past. However, reconstructing ancestral diets is very challenging, and exactly what was eaten during the Palaeolithic remains largely unknown.

Until now, there has been a heavy focus on the role of animal fats and protein in the development of the human brain and there is little doubt that increases in meat consumption from around 3.4 million years ago, was a major driver. However, the role of carbohydrates, particularly in the form of starch-rich plant foods, has largely been overlooked. But the human brain today uses up to 25 % of the body’s energy budget and up to 60 % of blood glucose as a general rule, while pregnancy and lactation in particular, place additional demands on the body’s glucose budget. In this study we integrated multiple lines of evidence from human genetics, archaeology, anthropology, physiology, and nutrition, to hypothesise that cooked carbohydrates played an important part in the evolution of the body, and particularly the brain, over the last 800,000 years.

Our results suggest that while meat was important, brain growth is less likely to have happened without the energy obtained from carbohydrates. While cooking has also been proposed as contributing to early brain development, it has a particularly profound effect on the digestibility of starch. Furthermore, humans are unusual among primates in that they have many copies of the salivary amylase gene (average of around six salivary amylase genes, other primates have only two) leading to more efficient starch digestion. This suggests that cooking starch-rich plants and having more amylase coevolved. We don’t know exactly when the number of amylase gene copies multiplied, but genetic data suggest it was in the last million years; a timeframe that brackets archaeological evidence for cooking and when our brain size increase accelerated (around 800,000 years ago). Salivary amylases are largely ineffective on raw crystalline starch, but cooking substantially increases both their energy-yielding potential and glycemia.

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Brain Waste Removal System Works Best While Sleeping on Side

Helene Benveniste, MD, PhD Professor of Anesthesiology and Radiology Vice Chair for Research, Department of Anesthesiology Stony Brook Medicine, Stony Brook NYMedicalResearch.com Interview with:
Helene Benveniste, MD, PhD
Professor of Anesthesiology and Radiology
Vice Chair for Research, Department of Anesthesiology
Stony Brook Medicine, Stony Brook NY

Medical Research: What is the background for this study?

Dr. Benveniste: The ‘glymphatic’ pathway is a part of the brain and is responsible for removal of waste products and excess fluid that built up especially during wakefulness. The concept was introduced by Nedergaard’s team in 2012 from University of Rochester. Importantly it has been shown to remove waste products such as soluble amyloid beta and tau protein which build up excessively in the brain of subjects afflicted with Alzheimer’s disease. The glymphatic system has been studied in detail in animal models (not yet humans) and actually is a brain-wide pathway which runs along (i.e. on the outside) of all vessels in the brain and connects to the space around the brain cells (referred to as the interstitial fluid (ISF) space). The outer part of the glymphatic network ‘tube’ is bordered by a certain type of brain cells so-called ‘astroglial’ cells which are arranged in a special way so that their endfeet cover >97% of the surface of all brain vessels. One can think of this as if the astroglial cell’s ‘endfeet’ are arranged as a donut shaped tube around all the vessels. On the astroglial endfeet there are special water channels (aquaporin-4 water channels) which are critical for how efficiently the glymphatic system can get rid of waste because it allows water to move fast through the brain tissue so as to ‘flush’ waste products out efficiently. The small gap between the astroglial endfeet also act like a ‘sieve’ so that only waste products of a certain size can access the entire pathway. Cerebrospinal fluid (CSF) circulates into the glymphatic pathway from the surface of the brain along the arteries which dives directly from the surface into the deeper part of the brain; and ultimately enters the space around the brain cells; and sweeps through it and thereby mixes with the interstitial fluid of the brain which contains waste products. The CSF-ISF mix with the waste products is then flushed out on the other ‘side’ along the veins and ultimately ends up in lymph vessels in the body and then in the blood.

It has been shown that the glymphatic pathway removes brain waste more efficiently in a state of ‘unconsciousness’ e.g. sleep or anesthesia when compared to wakefulness. Given this intriguing finding i.e. that sleeps seems to affect the waste clearance from the brain we thought that the next to look at was sleeping positions. We did these studies in anesthetized rodents.

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Important Protein Pathway In Brain Plasticity Identified

Erwin G. Van Meir, PhD Professor, Departments of Neurosurgery and Hematology & Medical Oncology Leader, Winship Cancer Institute Cancer Cell Biology Program Founding Director, Graduate Program in Cancer Biology Director, Laboratory for Molecular Neuro-Oncology Emory University School of Medicine Atlanta GA 30322MedicalResearch.com Interview with:
Erwin G. Van Meir, PhD
Professor, Departments of Neurosurgery and Hematology & Medical Oncology Leader, Winship Cancer Institute Cancer Cell Biology Program
Founding Director, Graduate Program in Cancer Biology
Director, Laboratory for Molecular Neuro-Oncology
Emory University School of Medicine Atlanta GA 30322

Medical Research: What is the background for this study? What are the main findings?

Dr. Van Meir: In this study we queried the role of the BAI1 protein in normal physiology. To do this we generated a transgenic mouse, which lacks the expression of the Bai1 gene. The mice had no obvious anomalies and reproduced according to mendelian rules. Since BAI1 is strongly expressed in the brain, including in neurons, we wondered whether they might have some cognitive defect that would only be revealed under specific testing conditions. We had the mice perform in an experiment that tests their ability to orient themselves in space and memorize the location of a hidden platform in a water maze. This experiment clearly demonstrated that the Bai1 deficient mice had deficits in spatial learning and memory. We then further probed the electrophysiological, anatomical and biochemical basis of this abnormal physiologic behavior and showed that hippocampal neurons had abnormal synaptic plasticity, reduced thickness of the post synaptic density and that this was associated with an increased degradation of a key PSD protein called PSD-95. Continue reading

Human Brains Age Less Than Previously Thought

Kamen Tsvetanov, PhD Centre for Speech, Language and the Brain Department of Psychology University of Cambridge Downing Street Cambridge, United KingdomMedicalResearch.com Interview with:
Kamen Tsvetanov, PhD

Centre for Speech, Language and the Brain
Department of Psychology
University of Cambridge
Downing Street
Cambridge, United Kingdom

 

Medical Research: What is the background for this study? What are the main findings?

MedicalResearch.com Interview with Filippo Calzolari PhD Institute of Stem Cell Research, ISF-N Helmholtz Zentrum München Neuherberg Germany

Brain areas with rich blood supply lower their vascular reactivity with ageing

Dr. Tsvetanov: Older brains may be more similar to younger brains than previously thought! In our study we have shown that changes in the aging brain previously observed using functional magnetic resonance imaging (fMRI) – one of the standard ways of measuring brain activity – may be due to changes in our blood vessels, rather than changes in the activity of our nerve cells, our neurons. Given the large number of fMRI studies used to assess the aging brain, this has important consequences for understanding how the brain changes with age and it challenges current theories of ageing.

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Brain Opioids Malresponsive in Major Depressive Disorder

Dr. David T. Hsu Ph.D Department of Psychiatry, Stony Brook University, Stony Brook, NY Department of Psychiatry The Molecular & Behavioral Neuroscience Institute University of Michigan, Ann Arbor, MIMedicalResearch.com Interview with:
Dr. David T. Hsu Ph.D
Department of Psychiatry, Stony Brook University, Stony Brook, NY
Department of Psychiatry
The Molecular & Behavioral Neuroscience Institute
University of Michigan, Ann Arbor, MI

Medical Research: What is the background for this study? What are the main findings?

Dr. Hsu: The opioid system is known for its role in reducing physical pain.  In 2013, we published a study showing that brain opioids are also released during social rejection and acceptance.  The current study shows that individuals diagnosed with major depressive disorder (MDD) do not have comparable levels of opioid release compared to healthy individuals from the previous study.

Medical Research: What should clinicians and patients take away from your report?

Dr. Hsu: These findings suggest that the recurrence and maintenance of major depressive disorder may be a consequence of the brain’s opioid response (or lack thereof) to positive and negative social events.  In healthy individuals, the brain’s opioid system may help an individual feel better after negative social interactions, and sustain good feelings after positive social interactions.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Hsu: Future research is needed to discover what current or novel treatments may help boost the response of the brain’s natural opioid system during positive and negative social events.

Citation:

Mol Psychiatry. 2015 Jan 20. doi: 10.1038/mp.2014.185. [Epub ahead of print]

It still hurts: altered endogenous opioid activity in the brain during social rejection and acceptance in major depressive disorder.

Hsu DT1, Sanford BJ2, Meyers KK3, Love TM2, Hazlett KE4, Walker SJ5, Mickey BJ2, Koeppe RA6, Langenecker SA7, Zubieta JK8.

 

MedicalResearch.com Interview with: Dr. David T. Hsu Ph.D, Department of Psychiatry, Stony Brook University, Stony Brook, NY, & Department of Psychiatry (2015). Brain Opioids Malresponsive in Major Depressive Disorder

Brain’s Protective Blood Barrier Becomes Leaky With Age

MedicalResearch.com Interview with:
V. Zlokovic, MD, PhD Professor and Chair Department of Physiology and Biophysics Keck School of Medicine of USC.
V. Zlokovic, MD, PhD
Professor and Chair
Department of Physiology and Biophysics
Keck School of Medicine of USC.

 

Medical Research: What is the background for this study? What are the main findings?

Dr. Zlokovic: Our team used high-resolution imaging of the living human brain to show for the first time that the brain’s protective blood barrier becomes leaky with age, starting at the hippocampus, a critical learning and memory center that is damaged by Alzheimer’s disease.

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Musical Training May Bolster Brain Plasticity Across A Lifetime

Dr. BidelmanMedicalResearch.com Interview with
Gavin M. Bidelman, Ph.D.
Assistant Professor Institute for Intelligent Systems
School of Communication Sciences & Disorders
University of Memphis
Memphis, TN  38105

MedicalResearch: What is the background for this study? What are the main findings?

Dr. Bidelman: Musical training as been shown to enhance brain function and impact behavioral skills (e.g., speech and language functions) in younger adults. In the current study, we investigated whether or not these advantages extend to older brains, which are thought to be less “plastic” (i.e., less malleable to experience/training). Older adults also often experience reduced speech recognition abilities later in life so we wanted to see if musicianship can serve as an effective means to bolster speech listening skills that decline across the lifespan.

Main findings:

1) On average, older musicians were 20% faster in identifying speech sounds behaviorally than their nonmusician peers. Interestingly, this is similar to the benefit we have observed in young people with musical training.

2) We were able to predict how well people classify/identify speech via (EEG) brain activity in both groups. However, this brain-behavior correspondence was ~2-3x better in older musicians. In other words, old musicians’ brains provide a much more detailed, clean, and accurate depiction of the speech signal which is likely why they are much more sensitive to speech behaviorally.

3) We compared neural responses generated from multiple levels of the auditory system and found that musicians had more coordination (significantly higher correlations) between different regions. This implies that the “musical brain” operates more in concert than in non-musicians.

All of these findings challenge conventional views that older brain’s are no longer plastic, are somehow noisier, and show poorer coordination across brain regions. In fact we show just the opposite. In older brains, musicianship does produce pervasive plasticity, provides cleaner (less noisy) representations of speech, and orchestrates more neural coordination.

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Bilingualism Can Preserve White Matter in Brain

Dr Christos Pliatsikas PhD Lecturer in Cognitive Psychology School of Psychology University of Kent Canterbury KentMedicalResearch.com Interview with:
Dr Christos Pliatsikas
PhD
Lecturer in Cognitive Psychology School of Psychology
University of Kent Canterbury Kent

Medical Research: What is the background for this study? What are the main findings?

Response: It has been proposed that lifelong bilingualism preserves the white matter structure of older bilinguals because of the increased cognitive demands that come with handling two languages for their entire life. We wanted to extend this by investigating whether active (or “immersive”) bilingualism in younger late bilinguals would give similar results.

We showed increased white matter integrity (or myelination) in several white matter tracts that have also been shown to be better preserved in older lifelong bilinguals, compared to monolinguals.  Based on our findings, we propose that any benefit of bilingualism to the brain structure is simply an effect of actively handling two languages without presupposing lifelong usage- our participants were only about 30 years old and had been active bilinguals for only about 7-8 years. In other words, immersive bilingualism, even in late bilinguals, leads to structural changes that can bring about benefits in older age, by assisting in the preservation of the white matter structure in the brain.

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NeuroGrid Can Capture Activity of Individual Neurons From Brain Surface

György Buzsáki, M.D., Ph.D. Biggs Professor of Neural Sciences NYU Neuroscience Institute New York University Langone Medical Center New York, NY 10016MedicalResearch.com Interview with:
György Buzsáki, M.D., Ph.D.

Biggs Professor of Neural Sciences
NYU Neuroscience Institute New York University
Langone Medical Center New York, NY 10016


Medical Research: What is the background for the NeuroGrid device?

Dr. Buzsaki: The main form of communication among neurons in the brain occurs through action potentials (‘spikes’). Understanding the mechanisms that translate spikes of individual neurons into perceptions, thoughts, and actions requires the ability to monitor large populations of neurons at the spatial and temporal resolution of their interactions.

We developed a novel, organic material-based, ultra-conformable, biocompatible and scalable neural interface array (the ‘NeuroGrid’) with neuron-size density electrodes capable of acquiring action potential of individual neurons from the surface of the brain.

The NeuroGrid has several innovative characteristics that overcome limitations in current methods of surface recording:

(i) light-weight and conformable architecture to establish stable electrical and mechanical contacts, thereby ensuring minimal damage to underlying tissue;

(ii) efficient abiotic/biotic interface resulting in a high signal to noise ratio and the ability to resolve spikes. This is achieved by using conducting polymers as the interfacing material. Conducting polymers are mix conductors, they can conduct electronics and ionic currents hence they can efficiently transduce ion based neural activity into electronic signals

(iii) scalable neuron-size density electrodes to allow isolation and characterization of multiple individual neurons’ action potential across the cortical surface.

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Codeine-Containing Cough Syrups Abuse Associated With Abnormal Brain White Matter

MedicalResearch.com Interview with:
Ying-wei Qiu, MD
Department of Medical imaging
Guangdong No. 2 Provincial People’s Hospital
Guangzhou, China;

Medical Research: What are the main findings of this study?

Dr. Ying-wei Qiu: The main findings include:

  1.  White matter (WM) integrity is abnormal in the IFO of bilateral temporal-occipital regions and right frontal region, and in the right corona radiata white matter in chronic Codeine-Containing Cough Syrups users.
  2. The abnormal white matter integrity related to the higher impulsivity in codeine-containing cough syrups users.
  3. The abnormal white matter integrity related to duration of Codeine-Containing Cough Syrups abuse in codeine-containing cough syrups users.

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Fish Consumption Linked to Brain Health

James T. Becker, Ph.D. Professor of Psychiatry, Psychology, and NeurologyMedicalResearch.com Interview with:
James T. Becker, Ph.D.
Professor of Psychiatry, Psychology, and Neurology
University of Pittsburgh

Medical Research: What are the main findings of the study?

Dr. Becker: We found that people who eat baked or broiled (but not fried) fish at least once every week had significantly larger brain volumes in areas critical for memory and cognition, namely, hippocampus, precuneus, posterior cingulate cortex, and orbital frontal cortex.
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