Tag: hippocampus

Weekly Neuroscience Update

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Bacterial curli promotes the aggregation of α-synuclein through cross-seeding, which leads to mitochondrial stress and neurodegeneration. Credit: The University of Hong Kong

Growing evidence indicates that gut microbiota plays a critical role in regulating the progression of neurodegenerative diseases such as Parkinson’s disease (PD) and Alzheimer’s disease (AD), but the molecular mechanism underlying such microbe-host interaction is still unclear. Now a research team at the University of Hong Kong (HKU) has discovered that bacteria-derived curli amyloid fibril promotes neurodegeneration in the host. This new study provides direct evidence to suggest that bacteria can secrete proteins that form an amyloid fibril, which enters the host neurons and promotes protein aggregation and neurodegeneration. Inhibiting the ability of the bacteria to secrete such proteins may be a preventative treatment for neurodegenerative diseases. 

Unusual visual inspection of objects by infants 9 months of age and older is predictive of a later diagnosis of autism spectrum disorder (ASD), new research has found.

A team of scientists recently published intriguing research on a tiny, splinter-like brain implant that doctors can slide deep into the folds of the brain and use to restore both muscular control over and sensation from a paralysis patient’s limbs.

A new study has found a new way to look at brain networks using the mathematical notion of fractals, to convey communication patterns between different brain regions as people listened to a short story. 

An experimental gene therapy that involves injecting CRISPR therapy directly into visually impaired patients’ eyeballs has vastly improved most volunteers’ vision — even allowing some to see color more vividly than ever before.

Preliminary new findings are raising concerns about the long-term effect of mild COVID-19 infection on neurological health and cognition.

Use of menopausal hormone therapy (MHT, also known as hormone replacement therapy, HRT) is not associated with an increased risk of developing dementia, regardless of hormone type, dose, or duration, concludes a large UK study.

Recent research provides empirical evidence to show the brain’s predictive ability forms the basis for musical phrasing.

Memories of past events and experiences are what define us as who we are, and yet the ability to form these episodic memories declines with age, certain dementias, and brain injury. However, a new study shows that low frequency repetitive transcranial magnetic stimulation—or rTMS—delivered over the left prefrontal cortex of the brain can improve memory performance by reducing the power of low frequency brain waves as memories form.

Finally this week, a new brain imaging study shows that the hippocampus is the brain’s storyteller, connecting separate, distant events into a single narrative.

 

Weekly Neuroscience Update

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A demonstration of the hippocampus and LEC. The image is credited to University of Warwick.

A new theory and model helps explain how entorhinal time ramping cells produce hippocampal time cells. The hippocampal cells allow for memory association between places and people to help recall event sequences.

Researchers shed light on why we need to sleep and discuss the effects of sleep deprivation.

In a groundbreaking finding, researchers have identified a new sensory organ under the skin that can detect pain as a result of impact or pinpricks. The organ comprises of glial cells with multiple long protrusions which collectively make up the mesh-like organ under the skin.

A 3D map of how the brain responds to words could unlock new ways to understand and treat dyslexia and speech disorders.

A visual test may be a new tool in the diagnosis of autism. Individuals on the autism spectrum are slower to dampen neural activity in response to visual stimuli in the brain. Using EEG data collected from the visual region, researchers could predict with 87% accuracy whether or not a person had ASD.

Contrary to popular belief, a new study reveals higher levels of testosterone may make people more sensitive to moral norms.

Boosting a single molecule in the brain can change “dispositional anxiety,” the tendency to perceive many situations as threatening, in nonhuman primates, researchers have found.

Finally this week, a new study suggests there may be genetic explanations for why some children with poor language also have poor mental health.

 

Weekly Neuroscience Update

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The link between vision problems and schizophrenia is well established, with as many as 62 percent of adult patients with schizophrenia experience visual distortions involving form, motion, or color. Image is for illustrative purposes only. Credit: University of Bristol.

The link between vision problems and schizophrenia is well established, with as many as 62 percent of adult patients with schizophrenia experience visual distortions involving form, motion, or color. Image is for illustrative purposes only. Credit: University of Bristol.

New research has identified the mechanisms that trigger disruption in the brain’s communication channels linked to symptoms in psychiatric disorders including schizophrenia. The study, published in the Proceedings of National Academy of Sciences, could have important implications for treating symptoms of brain disorders.

Genetic analysis of human patients has shown that mutations in genes involved in synaptic communication can drive neuropsychiatric and neurological diseases such as autism spectrum disorder and Alzheimer’s disease.

Researchers have discovered a way to predict human emotions based on brain activity.

Working 55 hours or more per week is linked to a 33% greater risk of stroke compared with working a standard 35 to 40 hour week, according to the largest study in this field so far,  published in The Lancet.

The permanence of memories has long thought to be mediated solely by the production of new proteins. However, new research has shown that the electrical activity of the brain may be a more primary factor in memory solidification.

The hippocampus in the brain’s temporal lobe is responsible for more than just long-term memory. Researchers have for the first time demonstrated that it is also involved in quick and successful conflict resolution

A brief period of postnatal visual deprivation, when early in life, drives a rewiring of the brain areas involved in visual processing, even if the visual restoration is completed well before the baby reaches one year of age, researchers revealed in Current Biology.

New research published in the British Journal of Psychiatry suggests that serious disorders of mood such as bipolar disorder may be the price that human beings have had to pay for more adaptive traits such as intelligence, creativity and verbal proficiency.

Finally this week, people with psychopathic characteristics are less likely to be affected by “contagious yawning” than those who are empathetic, according to a Baylor University psychology study.

Weekly Neuroscience Update

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The hippocampus is a region of the brain largely responsible for memory formation. Credit Salk Institute.

The hippocampus is a region of the brain largely responsible for memory formation. Credit Salk Institute.

Scientists have created a new model of memory that explains how neurons retain select memories a few hours after an event. This new framework provides a more complete picture of how memory works, which can inform research into disorders liked Parkinson’s, Alzheimer’s, post-traumatic stress and learning disabilities.

A switch in the brain of people with epilepsy dictates whether their seizures will be relatively mild or lead to a dangerous and debilitating loss of consciousness, Yale researchers have found.

By predicting our eye movements, our brain creates a stable world for us. Researchers used to think that those predictions had so much influence that they could cause us to make errors in estimating the position of objects. Neuroscientists at Radboud University have shown this to be incorrect. The Journal of Neuroscience published their findings – which challenge fundamental knowledge regarding coordination between brain and eyes.

Extreme and traumatic events can change a person — and often, years later, even affect their children. Researchers have now unmasked a piece in the puzzle of how the inheritance of traumas may be mediated.

Artists have structurally different brains compared with non-artists, a study has found. Participants’ brain scans revealed that artists had increased neural matter in areas relating to fine motor movements and visual imagery. The research, published in NeuroImage, suggests that an artist’s talent could be innate. But training and environmental upbringing also play crucial roles in their ability, the authors report.

Certain errors in visual perception in people with schizophrenia are consistent with interference or ‘noise’ in a brain signal known as a corollary discharge, a new study shows.

Finally this week,  a recent study has shown that use of abstract gestures is a powerful tool for helping children understand and generalize mathematical concepts.

 

 

The Art of the Brain

Hippocampus

Greg Dunn  swapped the life of a scientist for that of artist when he finished his Ph.D. in neuroscience at Penn in 2011.

Cerebellum – a region of the brain important for movement, balance, and motor memory

He has sold commissioned works to research labs and hospitals, and he says his prints are popular with neuroscientists, neurologists, and others with a special interest in the brain, including people with neurodegenerative disorders.

Developing cortex

This painting shows the developing human cerebral cortex, at about week 15 of gestation.

Weekly Neuroscience Update

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When selecting a video game to play, opting to turn on your Wii may provide a different experience than playing your Xbox, according to a study from Mississippi State University.

Excessive alcohol use accounts for 4% of the global burden of disease, and binge drinking particularly is becoming an increasing health issue. A new review article published Cortex highlights the significant changes in brain function and structure that can be caused by alcohol misuse in young people.

Working with patients with electrodes implanted in their brains, researchers have shown for the first time that areas of the brain work together at the same time to recall memories. The unique approach promises new insights into how we remember details of time and place.

Researchers at the University of Glasgow are hoping to help victims of stroke to overcome physical disabilities by helping their brains to ‘rewire’ themselves.

Keeping active can slow down the progression of memory loss in people with Alzheimer’s disease, a study has shown.

Neuroscientists have released the results of a new study that examines how fear responses are learned, controlled, and memorized. They show that a particular class of neurons in a subdivision of the amygdala plays an active role in these processes.

Neuroscience researchers from Tufts University have found that our star-shaped brain cells, called astrocytes, may be responsible for the rapid improvement in mood in depressed patients after acute sleep deprivation. This in vivo study, published in the current issue ofTranslational Psychiatry, identified how astrocytes regulate a neurotransmitter involved in sleep. The researchers report that the findings may help lead to the development of effective and fast-acting drugs to treat depression, particularly in psychiatric emergencies.

UC Berkeley neuroscientists have found that the slow brain waves generated during the deep, restorative sleep we typically experience in youth play a key role in transporting memories from the hippocampus – which provides short-term storage for memories – to the prefrontal cortex’s longer term “hard drive.”

Researchers have found altered connectivity in the brain network for body perception in people with anorexia: The weaker the connection, the greater the misjudgement of body shape.

A group of scientists planning to map all the major connections in the human brain began studying their first test subjects in August. The $30 million Human Connectome Project will trace the main neural pathways that link the roughly 500 major regions in the brain, illuminating how biological circuitry underlies our mental functions. MRI scans of 1,200 people, including 300 pairs of twins, will be used to compile an atlas of communication routes throughout the brain. The resulting blueprint will also reveal how brain connectivity varies from person to person.

What effect does alcohol have on the brain?

In this video, students explore how neuroscientists design and carry out research on the effects of alcohol on the human brain. Specifically, it focuses on the hippocampus, a brain structure that is involved in memory and spatial navigation. Studies of adult brains have found that the hippocampus is particularly vulnerable to heavy alcohol use. In the e-lab, students address these research questions: “Does alcohol also affect younger brains? If so, does it affect them in the same way?”

Your Brain On Cannabis: Part Two

This a follow on post from last month’s Your Brain On Cannabis, which has become one of the most widely read posts on Inside the Brain.

The effects of marijuana on your brain

The drug acts in areas of the brain involved in memory and emotion by interacting with two receptors – the so-called CB1 and CB2 cannabinoid receptors – to cause a profound effect on recent memory. Long term memories are not affected. One brain region called the hippocampus has receptors for endogenous “marijuana” (anandamide). Hippocampal damage is associated with failure to make new memories and if the CB1 and CB2 receptors are stimulated activity decreases in this brain region.  Interestingly, with repeated use, tolerance to loss of memory develops but this is often associated with a further increase in drug intake.

Learning and marijuana don’t mix

Marijuana also changes the way sensory information is processed in the brain and is associated with poor performance in school and increased delinquency. There is impairment in the ability to learn. Listening and repetition learning is also compromised. Heavy marijuana use is associated with deficits in mathematical skill and verbal expression. Taken together these effects can lead to catastrophic social and psychological consequences particularly for the young abuser – not to mention the lost employee productivity, public health care costs, accidents and crashes and loss of income – Americans spent $10.6 billion on marijuana purchases in 1999.

Marijuana is addictive

Marijuana addicts experience withdrawal and an animal model for dependence has been developed by scientists to understand how this happens. Withdrawal has been described after 21 days of heavy use and starts 10 hours after stopping and includes insomnia, nausea, anorexia, agitation, restlessness, irritability, depression and shaking (tremor). The symptoms peak within 48 hours and gradually wear off by the fifth day of abstinence.

The war on marijuana starts with spreading the word

During the 1970s in the US it was decided that a liberal approach be adopted to marijuana use and 11 states decriminalized marijuana, 30,000 head shops were allowed to spring up and “responsible-use” messages were promoted. The drinking age was lowered to 18 years and the sale of cigarettes and alcohol to teens was tolerated. By 1979 35% of adolescents, 65%of high school seniors and 70%of young adults had tried an illicit drug. These facts and the increase in drug-related crime prompted universal outrage and the laws were tightened up. As a result – from 1979 to 1992 marijuana use has dropped by 2/3 among adolescents, and young adults and daily marijuana use has dropped by 500%. However, it has taken over 20 years to undo the damage in the US.

In tackling the marijuana problem head-on  – the following common myths need to be debunked (i) marijuana is harmless, (ii) marijuana is not addictive (iii) youth experimentation is inevitable and (iv) the criminalization of marijuana use is what leads to crime, not the drug itself.

In the final part of this series on the effects of cannabis on your brain, we will take a look at the possible medicinal uses of marijuana.


Weekly Round Up

In a new study, participants who received electrical stimulation of the anterior temporal lobes were three times as likely to reach the fresh insight necessary to solve a difficult, unfamiliar problem than those in the control group. (Credit: iStockphoto/Andrey Volodin)

In this week’s round-up of the latest discoveries in the field of neuroscience – electric thinking caps, shrinking brains, brain controlled bionic arms, expanding memories..and much more.

Are we on the verge of being able to stimulate the brain to see the world anew with an electric thinking cap? Research by Richard Chi and Allan Snyder from the Centre for the Mind at the University of Sydney suggests that this could be the case.

Human brains have shrunk over the past 30,000 years, but it is not a sign of decreasing intelligence, according to scientists who suggest that evolution is making the key motor leaner and more efficient in an increasing population.

The LA Times reports that the FDA are about to test a brain-controlled prosthetic arm. The arm system, developed by the Defense Advanced Research Projects Agency, uses a microchip implanted in the brain to record and decode signals to neurons that control muscles linked to the prosthesis.

Interesting abstract in the New Scientist which shows that just as gardeners prune unwanted growths from flowers, the brain has its own molecular secateurs for trimming back unwanted connections.

Researchers have identified a protein that appears vital for forming the right kind of connections in the rapidly growing brain of newborn babies.

New research by scientists at Royal Holloway, University of London provides evidence that the cerebellum, a part of the brain used to store memories for skilled movements, could also store memories important for mental skills

Research conducted with deaf people in Nicaragua shows that language may play an important role in learning the meanings of numbers.

In the Neuroscience of Resilience, Lisa Brookes Kift is asking the question what does the brain and neuroscience have to do with building up our  resilience?

Finally, if you do just one thing this weekend, make it a walk. A report in the New York Times this week reveals that taking a walk may expand the hippocampus – a part of the brain important to the formation of memories. In healthy adults, the hippocampus begins to atrophy around 55 or 60. So get your walking shoes on this weekend!

Slow protein clearance ‘clue to Alzheimer’s’

Amyloid plaques build up in the brains of people with Alzheimer's disease. Image: BBC Health

The BBC News website this week reports on the latest research to suggest that people with Alzheimer’s disease clear a damaging protein from their brains more slowly than those who are healthy. With an ageing population,  dementia, including Alzheimer’s, is currently seen as one of the main health challenges in Ireland the UK.

Amyloid plaques are one of the hallmarks of Alzheimer’s disease. Amyloid is a general term for protein fragments that the body produces normally. Beta amyloid is a protein fragment snipped from an amyloid precursor protein. In a healthy brain, these protein fragments are broken down and eliminated. For some reason, in Alzheimer’s disease, the fragments accumulate to form hard, insoluble plaques.

The findings from this study suggests that people with Alzheimer’s disease clear the damaging protein from their brains 30% more slowly than those who are healthy suggesting that  it is the poor clearance of the protein, not the build-up, that is the problem. Admittedly it’s a small study – just 24 people were looked at, but exciting, and could help the understanding of the disease.

Not meaning to blow my own trumpet (ahem!) but in 2008 my research group showed how the amyloid protein might be toxic in higher concentration …by inappropriately increasing the concentrations of a neurotransmitter called glutamate in the hippocampus – a brain region long associated with Alzheimer’s disease*. It’s well known that high concentrations of glutamate can damage local nerve cells and thus impair the functioning of the hippocampus.

It’s exciting to see the pieces of evidence coming together as the search for an effective treatment for dementia continues apace.

*  O’Shea S.D., Smith I.M., McCabe O.M., Cronin M.M., Walsh D.M., O’Connor W.T. Sensors. 2008; 8(11):7428-7437.