Tag Archives: brain function

Gut bacteria affect brain health- Study

A growing pile of evidence indicates that the tens of trillions of microbes that normally live in our intestines — the so-called gut microbiome — have far-reaching effects on how our bodies function. Members of this microbial community produce vitamins, help us digest food, prevent the overgrowth of harmful bacteria and regulate the immune system, among other benefits. Now, a new study suggests that the gut microbiome also plays a key role in the health of our brains, according to researchers from Washington University School of Medicine in St. Louis.

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The study, in mice, found that gut bacteria — partly by producing compounds such as short chain fatty acids — affect the behavior of immune cells throughout the body, including ones in the brain that can damage brain tissue and exacerbate neurodegeneration in conditions such as Alzheimer’s disease. The findings, published Jan. 13 in the journal Science, open up the possibility of reshaping the gut microbiome as a way to prevent or treat neurodegeneration.

“We gave young mice antibiotics for just a week, and we saw a permanent change in their gut microbiomes, their immune responses, and how much neurodegeneration related to a protein called tau they experienced with age,” said senior author David M. Holtzman, MD, the Barbara Burton and Reuben M. Morriss III Distinguished Professor of Neurology. “What’s exciting is that manipulating the gut microbiome could be a way to have an effect on the brain without putting anything directly into the brain.”

Evidence is accumulating that the gut microbiomes in people with Alzheimer’s disease can differ from those of healthy people. But it isn’t clear whether these differences are the cause or the result of the disease — or both — and what effect altering the microbiome might have on the course of the disease.

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Hearing loss linked with dementia in older adults – Study

A new study led by researchers at the Johns Hopkins Bloomberg School of Public Health found that older adults with greater severity of hearing loss were more likely to have dementia, but the likelihood of dementia was lower among hearing aid users compared to non-users.

The findings, from a nationally representative sample of more than 2,400 older adults, are consistent with prior studies showing that hearing loss might be a contributing factor to dementia risk over time, and that treating hearing loss may lower dementia risk.

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The findings are highlighted in a research letter published online January 10 in the Journal of the American Medical Association.

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Researchers reveal how trauma changes the brain

Exposure to trauma can be life-changing – and researchers are learning more about how traumatic events may physically change our brains. But these changes are not happening because of physical injury, rather our brain appears to rewire itself after these experiences. Understanding the mechanisms involved in these changes and how the brain learns about an environment and predicts threats and safety is a focus of the ZVR Lab at the Del Monte Institute for Neuroscience at the University of Rochester, which is led by assistant professor Benjamin Suarez- Jimenez, Ph.D.

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“We are learning more about how people exposed to trauma learn to distinguish between what is safe and what is not. Their brain is giving us insight into what might be going awry in specific mechanisms that are impacted by trauma exposure, especially when emotion is involved,” said Suarez-Jimenez, who began this work as a post-doctoral fellow in the lab of Yuval Neria, Ph.D., professor at Columbia University Irving Medical Center.

Their research, recently published in Communications Biology, identified changes in the salience network – a mechanism in the brain used for learning and survival – in people exposed to trauma (with and without psychopathologies, including PTSD, depression, and anxiety). Using fMRI, the researchers recorded activity in the brains of participants as they looked at different-sized circles – only one size was associated with a small shock (or threat). Along with the changes in the salience network, researchers found another difference – this one within the trauma-exposed resilient group. They found the brains of people exposed to trauma without psychopathologies were compensating for changes in their brain processes by engaging the executive control network – one of the dominate networks of the brain.

“Knowing what to look for in the brain when someone is exposed to trauma could significantly advance treatments,” said Suarez-Jimenez, a co-first author with Xi Zhu, PhD, Assistant Professor of Clinical Neurobiology at Columbia, of this paper. “In this case, we know where a change is happening in the brain and how some people can work around that change. It is a marker of resilience.”

Adding the element of emotion

The possibility of threat can change how someone exposed to trauma reacts – researchers found this is the case in people with post-traumatic stress disorder (PTSD), as described in a recent study in Depression & Anxiety. Suarez-Jimenez, his fellow co-authors, and senior author Neria found patients with PTSD can complete the same task as someone without exposure to trauma when no emotion is involved. However, when emotion invoked by a threat was added to a similar task, those with PTSD had more difficulty distinguishing between the differences.

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Brain Benefits of Exercise

I think of this as a variation on one-picture-is-worth-1000 words.

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Omega-3s linked to improved midlife brain structure, cognition

Holy mackerel! Could eating salmon, cod, tuna, herring or sardines keep our brains healthy and our thinking agile in middle age? New research makes this connection.

Eating cold-water fish and other sources of omega-3 fatty acids may preserve brain health and enhance cognition in middle age, new evidence indicates.

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Having at least some omega-3s in red blood cells was associated with better brain structure and cognitive function among healthy study volunteers in their 40s and 50s, according to research published online Oct. 5 in Neurology®, the medical journal of the American Academy of Neurology. Faculty of The University of Texas Health Science Center at San Antonio (UT Health San Antonio) and other investigators of the Framingham Heart Study conducted the analysis.

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Decreased proteins, not amyloid plaques, tied to Alzheimer’s disease – Study

New research from the University of Cincinnati bolsters a hypothesis that Alzheimer’s disease is caused by a decline in levels of a specific protein, contrary to a prevailing theory that has been recently called into question.

UC researchers led by Alberto Espay, MD, and Andrea Sturchio, MD, in collaboration with the Karolinska Institute in Sweden, published the research on Oct. 4 in the Journal of Alzheimer’s Disease.

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Questioning the dominant hypothesis

The research is focused on a protein called amyloid-beta. The protein normally carries out its functions in the brain in a form that is soluble, meaning dissolvable in water, but it sometimes hardens into clumps, known as amyloid plaques.

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SuperAger brains contain ‘super neurons’ – NW

·  SuperAger neurons are even larger than those in individuals 20 to 30 years younger
·  These neurons do not have tau tangles that are a hallmark of Alzheimer’s
·  Larger neurons in the brain’s memory region are a biological signature of SuperAging trajectory

Neurons in an area of the brain responsible for memory (known as the entorhinal cortex) were significantly larger in SuperAgers compared to cognitively average peers, individuals with early-stage Alzheimer’s disease and even individuals 20 to 30 years younger than SuperAgers — who are aged 80 years and older, reports a new Northwestern Medicine study.

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These neurons did not harbor tau tangles, a signature hallmark of Alzheimer’s disease.

“The remarkable observation that SuperAgers showed larger neurons than their younger peers may imply that large cells were present from birth and are maintained structurally throughout their lives,” said lead author Tamar Gefen, an assistant professor of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine. “We conclude that larger neurons are a biological signature of the SuperAging trajectory.”  

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Machine learning gives glimpse of how a dog’s brain represents what it sees

Okay, this doesn’t have any obvious connection to living a long and healthy life, but I am a dog-lover and believe that there are more connections between our two species than meets the eye.

Scientists have decoded visual images from a dog’s brain, offering a first look at how the canine mind reconstructs what it sees. The Journal of Visualized Experiments published the research done at Emory University. 

Credit: Emory Canine Cognitive Neuroscience Lab

The results suggest that dogs are more attuned to actions in their environment rather than to who or what is doing the action.

The researchers recorded the fMRI neural data for two awake, unrestrained dogs as they watched videos in three 30-minute sessions, for a total of 90 minutes. They then used a machine-learning algorithm to analyze the patterns in the neural data.

“We showed that we can monitor the activity in a dog’s brain while it is watching a video and, to at least a limited degree, reconstruct what it is looking at,” says Gregory Berns, Emory professor of psychology and corresponding author of the paper. “The fact that we are able to do that is remarkable.”

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A brain mechanism underlying the evolution of anxiety

Monoamine neurotransmitters such as serotonin and dopamine play important roles in our cognitive and emotional functions. Their evolutionary origins date back to metazoans, and while the function of related genes is strongly evolutionarily conserved, genetic variation within and between species has been reported to have a significant impact on animal mental characteristics such as sociality, aggression, anxiety, and depression.

A research group led by Dr Daiki Sato and Professor Masakado Kawata has previously reported that the vesicular monoamine transporter 1 (VMAT1) gene, which transports neurotransmitters to secretory vesicles in neurons and secretory cells, has evolved through natural selection during human evolution. In particular, the 136th amino acid locus of this gene has evolved in the human lineage from asparagine (Asn) to threonine (Thr), and moreover, a new allele (isoleucine, Ile) has emerged and increased in its frequencies around the world. Previous reports suggested that people with the Ile genotype are less prone to depression and anxiety than those with the Thr genotype, but it was unclear how these human-specific mutations function in the brain and lead to changes in neuropsychiatric behavior.

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Social isolation impacts brain function in significant ways

Social isolation rewires the brain in myriad ways, potentially leading to anxiety, depression, addiction, and other behavioral changes. The findings were presented at Neuroscience 2021, the annual meeting of the Society for Neuroscience and the world’s largest source of emerging news about brain science and health. 

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Humans are a highly social species who crave social contact for their well-being. Loneliness induced by social isolation can cause significant neurological and behavioral changes that may lead to health issues. Given the widespread experience of loneliness during the COVID-19 pandemic, there is a need to better understand and prevent the long-term effects of social isolation. Scientists are just beginning to understand these changes and hope to find ways to curb their negative effects. 

Today’s new findings show:

  • Young mice exposed to chronic social isolation demonstrated a long-term deficit in social recognition and an altered circuit between the prefrontal cortex and nucleus accumbens (Yong-Seok Lee, Seoul National University College of Medicine).
  • Social isolation in adolescent mice led to increased cocaine use and relapse rates, as well as sex-dependent structural changes in the prefrontal cortex and nucleus accumbens (Lisa A. Briand, Temple University).
  • Social isolation in young rats led to an increase in weight, anxiety, and dopamine release in the nucleus accumbens, but exercise mitigated anxiety and weight gain (Enrique U. Pérez-Cardona, University of Puerto Rico at Carolina).
  • Lower social rank in mice is predictive of greater alcohol intake, but social isolation increases intake for all mice — regardless of rank — and increases the excitability of the basolateral amygdala (Reesha R. Patel, Salk Institute for Biological Studies).
  • A socially monogamous prairie vole model mimicked human responses after the loss of a partner; these behavioral changes may be linked to disturbances in the brain’s oxytocin system (Adam S. Smith, University of Kansas).

“This research shows that social isolation impacts many brain regions and affects many different behaviors, resulting in increased risk for disease,” said Alexa H. Veenema, the director of the Neurobiology of Social Behavior Laboratory and an associate professor at Michigan State University. “The pandemic has had a tremendous effect on our mental health. This research will provide us with insights about which specific neural circuits mediate the behavioral effects induced by social isolation. We can then find ways to restore these neural circuits, counteracting the consequences of social isolation”

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Brain changes that enable fine visual discrimination learning

Our visual perception of the world is often thought of as relatively stable. However, like all of our cognitive functions, visual processing is shaped by our experiences. During both development and adulthood, learning can alter visual perception. For example, improved visual discrimination of similar patterns is a learned skill critical for reading. In a new research study published in Current Biology, scientists have now discovered the neuronal changes that occur during learning to improve discrimination of closely related visual images.

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This study, led by first author Dr. Joseph Schumacher and senior author Dr. David Fitzpatrick at the Max Planck Florida Institute for Neuroscience, establishes a transformative approach to studying perceptual learning in the brain. Researchers imaged the activity of large numbers of single neurons over days to track the changes that occur while a visual discrimination task is learned, performing these experiments in a novel animal model, the tree shrew.

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9 ways to protect your heart and brain from the summer heat -AHA

Your favorite summertime playlist probably has more songs about surfing than about potential health risks. But with much of the nation having already sweated out a historic heat wave in June, health experts would like to add a note of caution to the mix.

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Hot weather is like a stress test for your heart, said Dr. Lance Becker, chair of emergency medicine at Northwell Health, a health care provider in New York. And some people respond poorly to such stress. “They could have a heart attack. Their congestive heart failure symptoms could get much worse. Or they could have an arrhythmia,” the medical term for an irregular heartbeat.

The risk to your heart and brain can be serious.

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Why is music good for the brain? – Harvard

Can music really affect your well-being, learning, cognitive function, quality of life, and even happiness, asks Harvard Health Publishing in a recent blog post. I have to confess that as a daily bike rider who plays music on a blue tooth speaker while riding, I was very happy to learn this.

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A recent survey on music and brain health conducted by AARP revealed some interesting findings about the impact of music on cognitive and emotional well-being:

  • Music listeners had higher scores for mental well-being and slightly reduced levels of anxiety and depression compared to people overall.
  • Of survey respondents who currently go to musical performances, 69% rated their brain health as “excellent” or “very good,” compared to 58% for those who went in the past and 52% for those who never attended.
  • Of those who reported often being exposed to music as a child, 68% rated their ability to learn new things as “excellent” or “very good,” compared to 50% of those who were not exposed to music.
  • Active musical engagement, including those over age 50, was associated with higher rates of happiness and good cognitive function.
  • Adults with no early music exposure but who currently engage in some music appreciation show above average mental well-being scores.

Let’s take a closer look at this study

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“Good cholesterol’ particles may have a role in Alzheimer’s prevention

First-ever study to measure high-density lipoprotein particle numbers in spinal fluid led by Keck School of Medicine of USC

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Medical guidelines meant to reduce risk for heart disease focus on levels of cholesterol in the blood, including low-density lipoproteins (LDL), labeled “bad cholesterol,” and high-density lipoproteins (HDL), labeled as “good.” Now, a new study suggests an important connection between good cholesterol particles in cerebrospinal fluid and brain health as well.

Researchers at the Keck School of Medicine of USC took samples of cerebrospinal fluid from people aged 60 and older and measured the amount of small HDL particles in each sample. The team found that a higher number of these particles in the fluid is associated with two key indicators that the particles might have a protective effect against Alzheimer’s disease.

One indicator is better performance on cognitive tests. The other indicator is higher circulating levels in the cerebrospinal fluid of a particular peptide — like a protein, but smaller — called amyloid beta 42. Although that peptide contributes to Alzheimer’s disease when it misfolds and clumps onto neurons, an increased concentration circulating around the brain and spine is actually linked to lower risk for the disease.

“This study represents the first time that small HDL particles in the brain have been counted,” said Hussein Yassine, M.D., an associate professor of medicine and neurology at the Keck School of Medicine of USC. “They may be involved with the clearance and excretion of the peptides that form the amyloid plaques we see in Alzheimer’s disease, so we speculate that there could be a role for these small HDL particles in prevention.”

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Scientists discover genetic variants that speed up and slow down brain aging

Researchers from a USC-led consortium have discovered 15 “hot spots” in the genome that either speed up brain aging or slow it down — a finding that could provide new drug targets to resist developmental delays, Alzheimer’s disease and other degenerative brain disorders, according to the University of Southern California (USC).

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The research appeared online in Nature Neuroscience.

“The big game-changer here is discovering locations on the chromosome that speed up or slow down brain aging in worldwide populations. These can quickly become new drug targets,” said Paul Thompson of USC, a lead author on the study and the co-founder and director of the ENIGMA Consortium. “Through our AI4AD [Artificial Intelligence for Alzheimer’s Disease] initiative we even have a genome-guided drug repurposing program to target these and find new and existing drugs that help us age better.”

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Anti-Inflammatory Diet May Be Best Bet for Cognitive Health

As people age, inflammation within their immune system increases, damaging cells. A new study shows that people who consumed an anti-inflammatory diet that includes more fruits, vegetables, beans, and tea or coffee, had a lower risk of developing dementia later in life. The research is published in the November 10, 2021, online issue of Neurology®, the medical journal of the American Academy of Neurology.

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“There may be some potent nutritional tools in your home to help fight the inflammation that could contribute to brain aging,” said study author Nikolaos Scarmeas, MD, PhD, of National and Kapodistrian University of Athens in Greece, and a Fellow of the American Academy of Neurology. “Diet is a lifestyle factor you can modify, and it might play a role in combating inflammation, one of the biological pathways contributing to risk for dementia and cognitive impairment later in life.”

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