. Scientific Frontline: Neuroscience
Showing posts with label Neuroscience. Show all posts
Showing posts with label Neuroscience. Show all posts

Thursday, February 2, 2023

HudsonAlpha scientists make new discovery linked to Alzheimer’s disease

Senior Scientist Lindsay Rizzardi, PhD
Photo Credit: Courtesy of HudsonAlpha
HudsonAlpha scientists identify transcription factors that may be involved in altered gene expression seen in Alzheimer’s disease

The human brain contains many types of cells that work together to ensure it functions properly. As arguably the most important organ in the human body, if something goes amiss with any brain cells or their connections to other cells, varying levels of neurological dysfunction can occur. Many neurological disorders arise from damage to brain cells due to a build-up of misfolded or aggregated proteins in the brain, like the tau protein and the amyloid-beta protein. Specific genes contain the instructions cells need for producing proteins. Changes to those genes can affect the protein production cycle, causing a change in the amount of protein produced or the conformation or quality of that protein. 

Alterations to the DNA code itself are only one of the ways that protein production can go awry. A class of proteins called transcription factors are a key component of how genes are expressed, causing a protein product to be made at higher or lower amounts than needed. These transcription factors act without changing the genetic makeup of the gene. These factors bind to DNA and recruit repressors or activators like RNA polymerase that coordinate DNA transcription and, ultimately, translation into a protein. 

Wednesday, February 1, 2023

Learning with all your senses: Multimodal enrichment as the optimal learning strategy of the future

Illustration Credit: John Hain

Neuroscientist Katharina von Kriegstein from Technische Universität Dresden and Brian Mathias from the University of Aberdeen have compiled extensive interdisciplinary findings from neuroscience, psychology, computer modelling and education on the topic of "learning" in a recent review article in the journal Trends in Cognitive Sciences. The results of the interdisciplinary review reveal the mechanisms the brain uses to achieve improved learning outcome by combining multiple senses or movements in learning. This kind of learning outcome applies to a wide variety of domains, such as letter and vocabulary acquisition, reading, mathematics, music, and spatial orientation.

Many educational approaches assume that integrating complementary sensory and motor information into the learning experience can enhance learning, for example gestures help in learning new vocabulary in foreign language classes. In her recent publication, neuroscientist Katharina von Kriegstein from Technische Universität Dresden and Brian Mathias of the University of Aberdeen summarize these methods under the term "multimodal enrichment." This means enrichment with multiple senses and movement. Numerous current scientific studies prove that multimodal enrichment can enhance learning outcomes. Experiments in classrooms show similar results.

A new tool for examining processes in the cerebellum

The Bochum research team: Bianca Preissing, Lennard Rohr, Ida Siveke and Tatjana Surdin (from left)
Photo Credit: © RUB, Marquard

Light can start a signal cascade in the cerebellum. This also illuminates processes that play an important role in cerebellar diseases.

Processes in the cerebellum are involved in various diseases that affect motor learning. A new tool developed by a Bochum working group helps to investigate this better: a light-activated protein that is coupled with part of an exciting receptor. Thanks to this optogenetic tool, light can activate a signaling pathway in the nerve cells of the cerebellum and observe its effects. So, the group around Dr. Ida Siveke from the working group of Prof. Dr. Stefan Herlitze at the Ruhr University Bochum show that the signal path is involved in cerebellar-controlled motor learning. The researchers report in the iSience journal.

Tuesday, January 31, 2023

How sound waves trigger immune responses to cancer in mice

The 700kHz, 260-element histotripsy ultrasound array transducer used in Prof. Xu’s lab.
Photo Credit: Marcin Szczepanski/Lead Multimedia Storyteller, Michigan Engineering

Technique pioneered at the University of Michigan could improve outcomes for cancer and neurological conditions

When noninvasive sound waves break apart tumors, they trigger an immune response in mice. By breaking down the cell wall “cloak,” the treatment exposes cancer cell markers that had previously been hidden from the body’s defenses, researchers at the University of Michigan have shown.

The technique developed at Michigan, known as histotripsy, offers a two-prong approach to attacking cancers: the physical destruction of tumors via sound waves and the kickstarting of the body’s immune response. It could potentially offer medical professionals a treatment option for patients without the harmful side effects of radiation and chemotherapy.

Until now, researchers didn’t understand how histotripsy was activating the immune system. A study from last spring showed that histotripsy breaks down liver tumors in rats, leading to the complete disappearance of the tumor even when sound waves are applied to only 50% to 75% of the mass. The immune response also prevented further spread, with no evidence of recurrence or metastases in more than 80% of the animals.

Common heart medicine is linked to a reduced risk of committing violent crimes

Yasmina Molero.
Photo Credit: Niklas Faye-Wevle Samuelson

Beta blockers, commonly used to treat heart disease and high blood pressure, can be linked to a reduced risk of committing violent crimes. It shows a new registry study from Karolinska Institutet and the University of Oxford published in the journal PLOS Medicine.

Beta blockers lower blood pressure by blocking the effect of hormones like adrenaline. The medicine is used to treat a variety of conditions including high blood pressure, cardiovascular events, heart failure and anxiety. It has also been suggested to work for clinical depression and aggression, but some studies have found a link to increased suicidal tendencies and the results are contradictory.

In the current study, the researchers investigated the relationship between beta blockers and hospitalization for mental illness, suicidal tendencies, suicide and reports of violent crime. They studied 1.4 million individuals in Sweden and compared periods with and without beta blockers in the same individual over an eight-year period (2006-2013). In this way, the researchers were able to control factors that can affect relationships, such as genetics or disease history.

Periods of medication were associated with a 13 percent lower risk of being charged with violent crime. Since it is an observational study, conclusions about causation should be interpreted with caution.

One way to deal with aggression

- If the results are confirmed in other studies, including randomized controlled trials, beta blocks may be considered as a way to manage aggression in individuals with psychiatric diagnoses, say Yasmina Molero, researchers at Department of Clinical Neuroscience and Department of Medical Epidemiology and Biostatistics at Karolinska Institutet.

Use of beta-blockers was also linked to eight percent lower risk of hospitalization due to mental illness and eight percent increased risk of being treated for suicidal tendencies or dying in suicide. However, these relationships were inconsistent.

- The risk of hospitalization and suicidal tendencies varied depending on psychiatric diagnosis and previous mental health problems, but also on the severity and type of heart problems that the beta blockers were used to treat. This indicates that there are no links between beta blockers and these outcomes, says Yasmina Molero.

Heart problems are associated with depression

Previous research has linked serious heart events to an increased risk of depression and suicide. This may indicate that the mental disorders and other disabilities associated with serious heart problems, rather than the treatment with beta blockers, increase the risk of serious mental illness, according to the researchers.

Funding: The study was funded by the Wellcome Trust, Forte, the American Foundation for Suicide Prevention and the Karolinska Institutet's funds. Co-author Henrik Larsson has received grants from Shire Pharmaceuticals, Medice Speaker Fees, Shire / Takeda Pharmaceuticals and Evolan Pharma as well as sponsorship for a conference on adhd from Shire / Takeda Pharmaceuticals, all outside the current study.

Published in journalPLOS Medicine

Source/CreditKarolinska Institutet

Reference Number: ns013123_02

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Focused ultrasound mediated liquid biopsy in a tauopathy mouse model

Hong Chen and her collaborators found that using focused-ultrasound-mediated liquid biopsy in a mouse model released more tau proteins and another biomarker for neurodegenerative disorders into the blood than without the intervention. This noninvasive method could facilitate diagnosis of neurodegenerative disorders.
Illustration Credit: Chen lab

Several progressive neurodegenerative disorders, including Alzheimer’s disease, are defined by having tau proteins in the brain. Researchers are seeking to identify the mechanisms behind these tau proteins to develop treatments, however, their efforts to detect biomarkers in blood has been hampered by the protective blood-brain barrier.

At Washington University in St. Louis, new research from the lab of Hong Chen, associate professor of biomedical engineering in the McKelvey School of Engineering and of radiation oncology in the School of Medicine, and collaborators found that using focused-ultrasound-mediated liquid biopsy in a mouse model released more tau proteins and another biomarker into the blood than without the intervention. This noninvasive method could facilitate diagnosis of neurodegenerative disorders, the researchers said.

The method, known as sonobiopsy, uses focused ultrasound to target a precise location in the brain. Once located, the researchers inject microbubbles into the blood that travel to the ultrasound-targeted tissue and pulsate, which safely opens the blood-brain barrier. The temporary openings allow biomarkers, such as tau proteins and neurofilament light chain protein (NfL), both indicative of neurodegenerative disorders, to pass through the blood-brain barrier and release into the blood.

An action plan to prevent Alzheimer’s disease

As the population ages, the number of people with Alzheimer’s disease in Europe will double by 2050.
Image Credit: Gerd Altmann

A task force led by UNIGE and HUG is laying the foundations for a preventive protocol.

Memory loss, behavioral changes, cognitive deficits: Alzheimer’s disease leads to a dramatic loss of autonomy for those affected and has a heavy impact on health costs. Its prevention has become a real social challenge. An international task force, led by the University of Geneva (UNIGE) and the Geneva University Hospitals (HUG), is setting out guidelines for innovative services to prevent Alzheimer’s disease. These will soon be an integral part of second-generation memory clinics. These guidelines are detailed in an article published in the Lancet Regional Health - Europe.

With 10 million people affected in Europe, Alzheimer’s disease is the most common neurodegenerative disease. It is characterized by progressive disabling memory loss and cognitive deficits caused by an accumulation of toxic proteins in the brain. Its social and economic impact is considerable. On a global scale, it is estimated to be worth around USD 1,500 billion per year* and in Switzerland CHF 11.8 billion per year**.

Friday, January 27, 2023

Not just mood swings but premenstrual depression

The scientists took images of the womens’ brain with positron emission tomography (PET) at different cycle times. 
Image Credit: © MPI CBS

Researchers find serotonin transporter in the brain increased

Scientists led by Julia Sacher from Max Planck Institute for Human Cognitive and Brain Sciences and Osama Sabri from the Leipzig University Hospital have discovered in an elaborate patient study that the transport of the neurotransmitter serotonin in the brain increases in women with premenstrual dysphoric disorder (PMDD) shortly before menstruation. Their findings provide the basis for a more targeted therapy of this specific mood disorder, in which patients only have to take antidepressants for a few days.

PMS, or premenstrual syndrome, is now a familiar term to many - about 50 per cent of all women experience these symptoms a few days before onset of their menstruation. The more severe form, called premenstrual dysphoric disorder (PMDD), affects eight percent of women of childbearing age and is associated with physical symptoms such as sleep disturbances or breast pain as well as psycho-emotional symptoms, including depression, loss of control, irritability, aggressiveness and concentration problems. As a result, many women with PMDD experience disruptions in their personal and professional lives.

Thursday, January 26, 2023

Researchers Unveil New Collection of Human Brain Atlases that Chart Postnatal Development

Surface-volume atlases from 2 weeks to 24 months.
Image Credit: © 2023, Ahmad et al., CCBY 4.0

Led by Pew-Thian Yap, PhD, researchers at the UNC School of Medicine created monthly infant brain atlases to help researchers analyze the developing brain in detail to investigate neurological disorders and other conditions.

Human brain atlases can be used by medical professionals to track normative trends over time and to pinpoint crucial aspects of early brain development. By using these atlases, they are able to see what typical structural and functional development looks like, making it easier for them to spot the symptoms of abnormal development, such as attention-deficit / hyperactivity disorder (ADHD), dyslexia, and cerebral palsy.

Pew-Thian Yap, PhD, professor in the UNC Department of Radiology, and colleagues in the department and the Biomedical Research Imaging Center (BRIC) have created a new collection of month-by-month infant brain atlas (IBA) that capture fine spatiotemporal details of the early developing brain.

Supplementation with amino acid serine eases neuropathy in diabetic mice

From left: Michal Handzlik and Christian Metallo
Photo Credit: Salk Institute

Approximately half of people with type 1 or type 2 diabetes experience peripheral neuropathy—weakness, numbness, and pain, primarily in the hands and feet. The condition occurs when high levels of sugar circulating in the blood damage peripheral nerves. Now, working with mice, Salk Institute researchers, in collaboration with the University of California San Diego, have identified another factor contributing to diabetes-associated peripheral neuropathy: altered amino acid metabolism.

The study, published in Nature, adds to growing evidence that some often-underappreciated, “non-essential” amino acids play important roles in the nervous system. The findings may provide a new way to identify people at high risk for peripheral neuropathy, as well as a potential treatment option. The team included UC San Diego bioengineering professor Prashant Mali, microbiome expert professor Rob Knight and pathologist Nigel A. Calcutt.

“We were surprised that dialing up and down a non-essential amino acid had such a profound effect on metabolism and diabetic complications,” says senior author Christian Metallo, a professor in Salk’s Molecular and Cell Biology Laboratory. “It just goes to show that what we think of as dogma can change under different circumstances, such as in disease conditions.”

Mechanical forces in the nervous system play a corrective role

The researchers visualized the forces acting on dendrites during pruning by measuring their lengths (blue/red) and the angles at dendritic branchpoints: A) before, B) after dendrite severing,
Image Credit: WWU - Rumpf Lab

Researchers at Münster University show in the fruit fly how mechanical tearing cuts neural connections

Nerve cells communicate with one another via long processes known as axons and dendrites, or, more generally, neurites. During development, these processes first grow and form connections with other cells, for example synapses with other nerve cells. Any neurites which are not properly linked, or are no longer needed, are removed by a corrective mechanism known as “pruning”. Such pruning processes can appear drastic, and neurites sometimes seem to be severed directly from the nerve cell. Researchers headed by Dr. Sebastian Rumpf from the Institute of Neuro- and Behavioral Biology at Münster University has now found the mechanism of neurite severing. In a study published in the Journal of Cell Biology, the team show that in sensory nerve cells of the fruit fly Drosophila melanogaster, pruning occurs through mechanical tearing.

Tuesday, January 24, 2023

Traffic pollution impairs brain function

fMRI shows decreased functional connectivity in the brain following exposure to traffic pollution.
Image Credit: Courtesy of University of British Columbia

First-in-the-world study suggests that even brief exposure to air pollution has rapid impacts on the brain

A new study by researchers at the University of British Columbia and the University of Victoria has shown that common levels of traffic pollution can impair human brain function in only a matter of hours.

The peer-reviewed findings, published in the journal Environmental Health, show that just two hours of exposure to diesel exhaust causes a decrease in the brain’s functional connectivity – a measure of how different areas of the brain interact and communicate with each other. The study provides the first evidence in humans, from a controlled experiment, of altered brain network connectivity induced by air pollution.

“For many decades, scientists thought the brain may be protected from the harmful effects of air pollution,” said senior study author Dr. Chris Carlsten, professor and head of respiratory medicine and the Canada Research Chair in occupational and environmental lung disease at UBC. “This study, which is the first of its kind in the world, provides fresh evidence supporting a connection between air pollution and cognition.”

Propionic acid protects nerve cells and supports their regeneration

Thomas Grüter and Kalliopi Pitarokoili (right) from the study team in St. Josef Hospital.
Photo Credit: RUB, Marquard

Some autoimmune diseases attack the nerves in the arms and legs. Researchers from Bochum are taking a new approach to counteract this damage.

In laboratory tests, researchers from St. Josef Hospital Bochum showed that propionate, the salt of a short-chain fatty acid, can protect nerves and help with their regeneration. The findings could be useful for the treatment of autoimmune diseases that damage nerve cells, such as chronic inflammatory demyelinating polyneuropathy (CIDP). Propionate naturally arises in the intestine when fiber is broken down. In previous studies, a team from the same department from St. Josef Hospital Bochum, clinic of the Ruhr University Bochum, has already proven that people with multiple sclerosis (MS) have a lack of propionate and can benefit from additional propionate intake. Accordingly, the substance could also be useful for patients with CIDP.

A group led by Dr. Thomas Grüter and private lecturer Dr. Kalliopi Pitarokoili from the Neurological University Clinic on St. Josef Hospital (Head of Prof. Dr. Ralf Gold), in the journal Proceedings of the National Academy of Sciences.

Genes Common to Different Species Found to Be Connected to the Development of Depression

Affective disorders, also known as mood disorders, are a group of mental illnesses that involve changes in emotional states.
Photo Credit:: Christopher Lemercier

Russian scientists performed a cross-species analysis of brain gene expression in danio fish, rats and humans to identify new common molecular targets for the therapy of affective disorders of the central nervous system induced by chronic stress. The study was able to identify several key brain proteins that may play important roles in the pathogenesis of affective disorders.

The article was published in the journal Scientific Reports. Affective disorders, also known as mood disorders, are a group of mental illnesses that involve changes in emotional states. They include various forms of depression and mania, psychosis, and increased anxiety. They are widespread because they occur not only as independent mental pathologies, but also as complications of neurological and other somatic diseases.

This fact determines the difficulty of diagnosis: people classify low mood, anxiety and irritability as temporary, situational manifestations. According to statistics, emotional disorders of varying severity occur in 20% of people, but only a quarter of them receive qualified help.

Monday, January 23, 2023

Scientists explain emotional ‘blunting’ caused by common antidepressants

Depression
Photo Credit: Ethan Sykes

According to the NHS, more than 8.3 million patients in England received an antidepressant drug in 2021/22. A widely-used class of antidepressants, particularly for persistent or severe cases, is selective serotonin reuptake inhibitors (SSRIs). These drugs target serotonin, a chemical that carries messages between nerve cells in the brain and has been dubbed the ‘pleasure chemical’.

One of the widely-reported side effects of SSRIs is ‘blunting’, where patients report feeling emotionally dull and no longer finding things as pleasurable as they used to. Between 40-60% of patients taking SSRIs are believed to experience this side effect.

To date, most studies of SSRIs have only examined their short-term use, but, for clinical use in depression these drugs are taken chronically, over a longer period of time. A team led by researchers at the University of Cambridge, in collaboration with the University of Copenhagen, sought to address this by recruiting healthy volunteers and administering escitalopram, an SSRI known to be one of the best-tolerated, over several weeks and assessing the impact the drug had on their performance on a suite of cognitive tests.

In total, 66 volunteers took part in the experiment, 32 of whom were given escitalopram while the other 34 were given a placebo. Volunteers took the drug or placebo for at least 21 days and completed a comprehensive set of self-report questionnaires and were given a series of tests to assess cognitive functions including learning, inhibition, executive function, reinforcement behavior, and decision-making.

Friday, January 20, 2023

How Huntington’s disease affects different neurons

Neuroscientists at MIT have shown that two distinct cell populations in the striatum are affected differently by Huntington’s disease.
Image Credit: Leterrier, NeuroCyto Lab, INP, Marseille, France

In patients with Huntington’s disease, neurons in a part of the brain called the striatum are among the hardest-hit. Degeneration of these neurons contributes to patients’ loss of motor control, which is one of the major hallmarks of the disease.

Neuroscientists at MIT have now shown that two distinct cell populations in the striatum are affected differently by Huntington’s disease. They believe that neurodegeneration of one of these populations leads to motor impairments, while damage to the other population, located in structures called striosomes, may account for the mood disorders that are often see in the early stages of the disease.

“As many as 10 years ahead of the motor diagnosis, Huntington’s patients can experience mood disorders, and one possibility is that the striosomes might be involved in these,” says Ann Graybiel, an MIT Institute Professor, a member of MIT’s McGovern Institute for Brain Research, and one of the senior authors of the study.

Using single-cell RNA sequencing to analyze the genes expressed in mouse models of Huntington’s disease and postmortem brain samples from Huntington’s patients, the researchers found that cells of the striosomes and another structure, the matrix, begin to lose their distinguishing features as the disease progresses. The researchers hope that their mapping of the striatum and how it is affected by Huntington’s could help lead to new treatments that target specific cells within the brain.

Friday, January 6, 2023

The brain’s ability to perceive space expands like the universe

New experiences are absorbed into neural representations over time, symbolized here by a hyperboloid hourglass.
Illustration Credit: Salk Institute

Salk researchers find that neural networks responsible for spatial perception change in a nonlinear manner and may have implications for neurodegenerative disorders like Alzheimer’s disease

Young children sometimes believe that the moon is following them, or that they can reach out and touch it. It appears to be much closer than is proportional to its true distance. As we move about our daily lives, we tend to think that we navigate space in a linear way. But Salk scientists have discovered that time spent exploring an environment causes neural representations to grow in surprising ways.

The findings, published in Nature Neuroscience show that neurons in the hippocampus essential for spatial navigation, memory, and planning represent space in a manner that conforms to a nonlinear hyperbolic geometry—a three-dimensional expanse that grows outward exponentially. (In other words, it’s shaped like the interior of an expanding hourglass.) The researchers also found that the size of that space grows with time spent in a place. And the size is increasing in a logarithmic fashion that matches the maximal possible increase in information being processed by the brain.

Thursday, January 5, 2023

A Theory of Rage

Left: Aditya Nair, Caltech graduate student and study's lead author. Photo Credit: J. Ehlert
Center: Ann Kennedy, Theoretical neuroscientist. Photo Credit: Ann Kennedy
Right: David Anderson, Professor of Biology Photo Credit: Courtesy of David Anderson

Have you ever been cut off while driving and found yourself swearing and laying on the horn? Or come home from a long day at work and lashed out at whoever left the dishes unwashed? From petty anger to the devastating violence we see in the news, acts of aggression can be difficult to comprehend. Research has yielded puzzling paradoxes about how rage works in the brain. But a new study from Caltech, pioneering a machine-learning research technique in the hypothalamus, reveals unexpected answers on the nature of aggression.

The hypothalamus is a brain region linked to many innate survival behaviors like mating, hunting, and the fight-or-flight response. Scientists have long believed that neurons in the hypothalamus are functionally specific—that is, certain groups of neurons correlate to certain specific behaviors. This seems to be the case in mating behavior, where neuron groups in the medial preoptic area (MPOA) of the hypothalamus, when stimulated, cause a male mouse to mount a female mouse. These same neurons are active when mounting behavior occurs naturally. The logical conclusion is that these neurons control mounting in mice.

Wednesday, January 4, 2023

Common Fatty Acid Contributes to Temperature and Pain Sensitivity in Psoriasis Plaques

Photo Credit: Eszter Miller

A common fatty acid found in the Western diet breaks down into compounds that contribute to increased temperature and pain – but not itch – sensitivity in psoriatic lesions. The finding could lead to better understanding of how lipids communicate with sensory neurons, and potentially to improved pain and sensitivity treatments for psoriasis patients.

Linoleic acid is a fatty acid found in vegetable oils, nuts and seeds, and is one of the predominant fatty acids found in the Western diet. Metabolites from linoleic acid – the products formed when the body breaks it down through digestion – play a role in skin barrier function.

“We noticed high levels of two types of lipids derived from linoleic acid in psoriatic lesions,” says Santosh Mishra, associate professor of neuroscience at North Carolina State University and corresponding author of the research. “That led us to wonder whether the lipids might affect how sensory neurons in these lesions communicate. We decided to investigate whether their presence could be related to the temperature or pain hypersensitivity that many psoriasis patients report.”

Sunday, January 1, 2023

Good and bad feelings for brain stem serotonin

An illustration of the facial expression changes in mice following stimulation and inhibition of the median raphe nucleus
Image Credit: Yu Ohmura

New insights into the opposing actions of serotonin-producing nerve fibers in mice could lead to drugs for treating addictions and major depression.

Scientists in Japan have identified a nerve pathway involved in the processing of rewarding and distressing stimuli and situations in mice.

The new pathway, originating in a bundle of brain stem nerve fibers called the median raphe nucleus, acts in opposition to a previously identified reward/aversion pathway that originates in the nearby dorsal raphe nucleus. The findings, published by scientists at Hokkaido University and Kyoto University with their colleagues in the journal Nature Communications, could have implications for developing drug treatments for various mental disorders, including addictions and major depression.

Previous studies had already revealed that activating serotonin-producing nerve fibers from the dorsal raphe nucleus in the brain stem of mice leads to the pleasurable feeling associated with reward. However, selective serotonin reuptake inhibitors (SSRIs), antidepressant drugs that increase serotonin levels in the brain, fail to exert clear feelings of reward and to treat the loss of ability to feel pleasure associated with depression. This suggests that there are other serotonin-producing nerve pathways in the brain associated with the feelings of reward and aversion.

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Not just mood swings but premenstrual depression

The scientists took images of the womens’ brain with positron emission tomography (PET) at different cycle times.  Image Credit: © MPI CBS R...

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