Showing posts with label Neuroscience. Show all posts
Showing posts with label Neuroscience. Show all posts

Friday, May 20, 2022

Neuroscientists Find Brain Mechanism Tied to Age-Related Memory Loss

As the brain ages, a region in the hippocampus becomes imbalanced, causing forgetfulness. Scientists say understanding this region of the brain and its function may be the key to preventing cognitive decline.

Working with rats, neuroscientists at Johns Hopkins University have pinpointed a mechanism in the brain responsible for a common type of age-related memory loss. The work, published in Current Biology, sheds light on the workings of aging brains and may deepen our understanding of Alzheimer's disease and similar disorders in humans.

"We're trying to understand normal memory and why a part of the brain called the hippocampus is so critical for normal memory," said senior author James Knierim, a professor at the university's Zanvyl Krieger Mind/Brain Institute. "But also with many memory disorders, something is going wrong with this area."

Neuroscientists know that neurons in the hippocampus, located deep in the brain's temporal lobe, are responsible for a complementary pair of memory functions called pattern separation and pattern completion. These functions occur in a gradient across a tiny region of the hippocampus called CA3.

In normal brains, pattern separation and pattern completion work hand-in-hand to sort and make sense of perceptions and experiences, from the most basic to the highly complex. If you visit a restaurant with your family and a month later you visit the same restaurant with friends, you should be able to recognize that it was the same restaurant, even though some details have changed—this is pattern completion. But you also need to remember which conversation happened when, so you do not confuse the two experiences—this is pattern separation.

Thursday, May 19, 2022

Using Light and Sound to Reveal Rapid Brain Activity in Unprecedented Detail

The image shows the vasculature of the brain, and the colors illuminate how capillaries experience varying levels of oxygenation as the brain undergoes hypoxia.
Credit: Duke University

Duke researchers use a combination of hardware innovations and machine learning algorithms to create the fastest photoacoustic imaging tool available

Biomedical engineers at Duke University have developed a method to scan and image the blood flow and oxygen levels inside a mouse brain in real-time with enough resolution to view the activity of both individual vessels and the entire brain at once.

This new imaging approach breaks long-standing speed and resolution barriers in brain imaging technologies and could uncover new insights into neurovascular diseases like stroke, dementia and even acute brain injury.

The research appeared in the Nature journal Light: Science & Applications.

Imaging the brain is a balancing act. Tools need to be fast enough to capture rapid events, like a neuron firing or blood flowing through a capillary, and they need to show activity at different scales, whether it’s across the entire brain or at the level of a single artery.

Wednesday, May 18, 2022

Spying on Thousands of Neurons in the Brain’s Vision Center Simultaneously

Scientists tracked how individual neurons (white dots)
across the mouse visual center responded when the
animals saw an image on a screen.
That let the team trace the sequence
of events triggered when the eyes detect an important sight.
Credit: S. Ebrahimi et al./Nature 2022
Using a custom-built microscope to peer into the mouse brain, scientists have tracked the activity of single neurons across the entire visual cortex.

These recordings, made in the tenths of seconds after the animals saw a cue on a screen, expose the complex dynamics involved in making sense of what the eyes see. In an unprecedented combination of breadth and detail, the results describe the behavior of more than 21,000 total neurons in six mice over five days, Howard Hughes Medical Institute Investigator Mark Schnitzer’s team reports in the journal Nature on May 18, 2022.

His team is the first to get a glimpse of individual cells’ activity occurring at the same time throughout eight parts of the brain involved in vision. “People have studied these brain areas before, but prior imaging studies did not have cellular resolution across the entire visual cortex,” says Schnitzer, a neuroscientist at Stanford University.

The work highlights the dramatic sequence of events that unfolds in the brain from the instant it receives messages from the eyes until it decides how to respond to that sight. The researchers’ far-reaching but fine-grained imaging approach made it possible for them to collect an “incredible” set of data, says Tatiana Engel, a computational neuroscientist at Cold Spring Harbor Laboratory who was not involved in the study.

Monday, May 2, 2022

‘Resetting’ the injured brain offers clues for concussion treatment

Jonathan Godbout, professor of neuroscience
Credit: Ohio State University
New research in mice raises the prospects for development of post-concussion therapies that could ward off cognitive decline and depression, two common conditions among people who have experienced a moderate traumatic brain injury.

The study in mice clarified the role of specific immune cells in the brain that contribute to chronic inflammation. Using a technique called forced cell turnover, researchers eliminated these cells in the injured brains of mice for a week and then let them repopulate for two weeks.

“It’s almost like hitting the reset button,” said senior study author Jonathan Godbout, professor of neuroscience in The Ohio State University College of Medicine.

Compared to brain-injured mice recovering naturally, mice that were given the intervention showed less inflammation in the brain and fewer signs of thinking problems 30 days after the injury.

Though temporarily clearing away these cells, called microglia, in humans isn’t feasible, the findings shed light on pathways to target that could lower the brain’s overall inflammatory profile after a concussion, potentially reducing the risk for behavioral and cognitive problems long after the injury.

“In a moderate brain injury, if the CT scan doesn’t show damage, patients go home with a concussion protocol. Sometimes people come back weeks, months later with neuropsychiatric issues. It’s a huge problem affecting millions of people,” said Godbout, faculty director of Ohio State’s Chronic Brain Injury Program and assistant director of basic science in the Institute for Behavioral Medicine Research.

Thursday, April 28, 2022

Researchers Discover New Function Performed by Nearly Half of Brain Cells

Scientists say the discovery of a new function by cells known as astrocytes opens a whole new direction for neuroscience research.
Illustration Credit: Siena Fried

Researchers at Tufts University School of Medicine have discovered a previously unknown function performed by a type of cell that comprises nearly half of all cells in the brain.

The scientists say this discovery in mice of a new function by cells known as astrocytes opens a whole new direction for neuroscience research that might one day lead to treatments for many disorders ranging from epilepsy to Alzheimer’s to traumatic brain injury.

It comes down to how astrocytes interact with neurons, which are fundamental cells of the brain and nervous system that receive input from the outside world. Through a complex set of electrical and chemical signaling, neurons transmit information between different areas of the brain and between the brain and the rest of the nervous system.

Until now, scientists believed astrocytes were important, but lesser cast members in this activity. Astrocytes guide the growth of axons, the long, slender projection of a neuron that conducts electrical impulses. They also control neurotransmitters, chemicals that enable the transfer of electrical signals throughout the brain and nervous system. In addition, astrocytes build the blood-brain barrier and react to injury.

But they did not seem to be electrically active like the all-important neurons—until now.

Wednesday, April 27, 2022

Five diseases attack language areas in brain

Each condition causes a different type of language impairment in primary progressive aphasia (PPA)

  • Word comprehension is lost for some patients, others lose grammar
  • Most extensive study to date on PPA
  • Disease is often misdiagnosed in early stages, missing chance for treatment
  • Not all dementia is caused by Alzheimer’s disease

There are five different diseases that attack the language areas in the left hemisphere of the brain that slowly cause progressive impairments of language known as primary progressive aphasia (PPA), reports a new Northwestern Medicine study.

“We’ve discovered each of these diseases hits a different part of the language network,” said lead author Dr. M. Marsel Mesulam, director of Northwestern’s Mesulam Center for Cognitive Neurology and Alzheimer’s Disease. “In some cases, the disease hits the area responsible for grammar, in others the area responsible for word comprehension. Each disease progresses at a different rate and has different implications for intervention.”

This study published in the journal Brain is based on the largest set of PPA autopsies — 118 cases — ever assembled.

“The patients had been followed for more than 25 years, so this is the most extensive study to date on life expectancy, type of language impairment and relationship of disease to details of language impairment,” said Mesulam, also chief of behavioral neurology at Northwestern University Feinberg School of Medicine.

Patients with PPA were prospectively enrolled in a longitudinal study that included language testing and imaging of brain structure and brain function. The study included consent to brain donation at death.

Sunday, April 10, 2022

Wireless neuro-stimulator to revolutionize patient care

Many neurological disorders like Parkinson’s, chronic depression and other psychiatric conditions could be managed at home, thanks to a collaborative project involving researchers at the University of Queensland (UQ).

Queensland Brain Institute (QBI) Professor Peter Silburn AM said his team, together with Neurosciences Queensland and Abbott Neuromodulation have developed a remote care platform which allows patients to access treatment from anywhere in the world.

“By creating the world’s first integrated and completely wireless remote care platform, we have removed the need for patients to see their doctor in person to have their device adjusted,” Professor Silburn said.

Electrodes are surgically inserted into the brain and electrical stimulation is delivered by a pacemaker which alters brain function - providing therapeutic relief and improving quality of life.

This digital platform allows clinicians to monitor patients remotely, as well as adjust the device to treat and alleviate symptoms in real time.

“We have shown that it is possible to minimize disruption to patients’ and caregivers’ lifestyles by increasing accessibility to the service, saving time and money,” Professor Silburn said.

“There are no cures for many of these conditions which often require life-long treatment and care, so for those people the device would be a game-changer.”

He said the system also fostered increasingly personalized treatment and data-driven clinical decisions, which could improve patient care.

Saturday, April 9, 2022

Newborn cells in the epileptic brain provide a potential target for treatment

Altered cells create an electrical “fire” in patients with epilepsy.
Credit: BioRender illustration by Aswathy Ammothumkandy/Bonaguidi Lab/USC Stem Cell

Over the years, everyone loses a few brain cells. A study led by scientists from USC Stem Cell and the USC Neurorestoration Center presents evidence that adults can replenish at least some of what they’ve lost by generating new brain cells, and that this process is dramatically altered in patients with long-term epilepsy. The findings are published in Nature Neuroscience.

“Our study is the first to detail the presence of newborn neurons and an immature version of a related cell type, known as astroglia, in patients with epilepsy,” said Michael Bonaguidi, an assistant professor of stem cell biology and regenerative medicine, gerontology, and biomedical engineering at USC. “Our findings furnish surprising new insights into how immature astroglia might contribute to epilepsy—opening an unexplored avenue toward the development of new anti-seizure medications for millions of people.”

First author Aswathy Ammothumkandy, who is a postdoctoral fellow in the Bonaguidi Lab, and her colleagues collaborated with USC neurosurgeons Charles Liu and Jonathan Russin, who often treat patients with seizures that can’t be controlled with medication. Drug resistance is particularly common with mesial temporal lobe epilepsy, or MTLE, and affects one-third of all patients with this form of the disease. As a result, some patients need to undergo surgery to remove the section of the brain, the hippocampus, that causes their seizures.

Thursday, April 7, 2022

New Insights into the Neuroscience Behind Conscious Awareness of Choice

Nancy Smith participates in neuroscience experiments to play a digital piano using a brain-computer interface.
Credit: T. Aflalo

When you absentmindedly reach out to pick up your cup of coffee and take a sip, what happens in your brain? Many studies have shown that brain activity begins to ramp up even before you are aware of your choice to move. But this poses a conundrum: Do we have free will to make our own choices, if our brains are already preparing for actions before we are even conscious of them?

Now, a new study from the laboratory of Richard Andersen, James G. Boswell Professor of Neuroscience, and Leadership Chair and Director of the T&C Chen Brain–Machine Interface Center, gives new insights into how the brain encodes for our choices about movement. The research indicates that brain activity of abstract high-level choices (such as the desire to consume more coffee) connects to the actual actions (such as reaching out a hand) even before the awareness of such choices to move.

"The implementation of current brain-machine interfaces that read out the intent of patients assume that they are simultaneously consciously aware of the intent that is being decoded from their brains," says Andersen. "Taking into account this early subconscious activity is critical when designing algorithms for brain-computer interfaces that could one day enable people with spinal or brain damage to regain function."

Tuesday, April 5, 2022

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.

The research appeared online Tuesday 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.”

ENIGMA is working group based at USC that is exploring a vast trove of brain data and has published some of the largest-ever neuroimaging studies of schizophrenia, major depression, bipolar disorder, epilepsy, Parkinson’s disease, and even HIV infection.

To discover the hot spots, or genomic loci, more than 200 ENIGMA-member scientists from all over the world looked for people whose brains were scanned twice with MRI. The scans provided a measure of how fast their brains were gaining or losing tissue in regions that control memory, emotion and analytical thinking.

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Using Light and Sound to Reveal Rapid Brain Activity in Unprecedented Detail

The image shows the vasculature of the brain, and the colors illuminate how capillaries experience varying levels of oxygenation as the brai...

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