Tag: neurology

Categories : NeurologyTags :

Scientists Crack Neuron Information Storage Code

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A team of scientists from the UK and Australia have discovered that single neurons can store electrical patterns, similar to memories. This represents a breakthrough towards solving how neural systems are able to process and store information.

By comparing predictions from mathematical modeling to lab-based experiments with mammalian neurons, they were able to determine how different parameters, such as how long it takes for neuronal signals to be processed and how sensitive a cell is to external signals, affect how neural systems encode information.

The research team found that a single neuron is able to select between different patterns, dependent on the properties of each individual stimulus, for example slight differences in stimulation timing resulted in the emergence of no electrical activity spikes, single spikes per delay or two spikes per delay,

By opening up new avenues into research on the encoding of information in the brain and how this relates to memory formation, the study could also allow new insights into the causes and treatments of mental health conditions such as dementia.

“This work highlights how mathematical analysis and wet-lab experiments can be closely integrated to shed new light on fundamental problems in neuroscience,” said Dr Wedgwood. “That the theoretical predictions were so readily confirmed in experiments gives us great confidence in the mathematical approach as a tool for understanding how individual cells store patterns of activity. In the long run, we hope that this is the first step to a better understanding of memory formation in neural networks.”

Professor Krauskopf from the University of Auckland remarked, “The research shows that a living neuron coupled to itself is able to sustain different patterns in response to a stimulus. This is an exciting first step towards understanding how groups of neurons are able to respond to external stimuli in a precise temporal manner.”

“Communication between neurons occurs over large distances. The communication delay associated with this plays an important role in shaping the overall response of a network. This insight is crucial to how neural systems encode memories, which is one of the most fundamental questions in neuroscience,” added Professor Tsaneva from the University of Exeter’s Living Systems Institute.

Source: Medical Xpress

Journal information: Kyle C. A. Wedgwood et al, Robust spike timing in an excitable cell with delayed feedback, Journal of The Royal Society Interface (2021). dx.doi.org/10.1098/rsif.2021.0029

Categories : Implants and ProsthesesTags :

Neural Control of Prosthetic Ankle Can Restore Agility

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Female athlete with prosthetic leg relaxes on a sporting field. Photo by Anna Shvets from Pexels

A recent case study demonstrates that, with training, neural control of a prosthetic ankle with a powered joint can restore agility. 

Traditional prosthetic ankle joints result in slower walking and abnormal gaits due to the way they differ from normal human ankles in distributing walking loads. Autonomously controlled powered prosthetic ankles can restore additional function to users by providing the extra work involved in a natural walking gait. However, they are currently only designed to assist walking or standing, and not to tackle specialised tasks such as squatting.

“This case study shows that it is possible to use these neural control technologies, in which devices respond to electrical signals from a patient’s muscles, to help patients using robotic prosthetic ankles move more naturally and intuitively,” said corresponding author Helen Huang, Jackson Family Distinguished Professor in the Joint Department of Biomedical Engineering at NC State and UNC

“This work demonstrates that these technologies can give patients the ability to do more than we previously thought possible,” says Aaron Fleming, first author of the study and a Ph.D. candidate in the joint biomedical engineering department.

Most research on robotic prosthetic ankles has focused on autonomous control, meaning that the prosthesis handles the fine motions when the wearer decides to walk or stan.

Huang, Fleming and their collaborators sought to find out if amputees could be trained to use a neurally controlled prosthetic ankle to regain more control in the many common motions that people make with their ankles beyond simply walking.

Their powered prosthesis reads electrical signals from two residual calf muscles, which are responsible for controlling ankle motion, and converts the signals into commands for moving the prosthesis.

The researchers recruited a study participant with an amputation between the knee and the ankle, and fitted the powered prosthetic ankle on the participant and did an initial evaluation. Over two and a half weeks, the participant then had five, two-hour training sessions with a physical therapist. A second evaluation was conducted on training completion.

Having had the training, the participant was able to perform a variety of previously challenging tasks, such as going from sitting to standing without any external assistance or squatting to pick something up without compensating for the movement with other body parts. However the participant’s own stability, both self-reported and empirically measured in such tests as standing on foam, was dramatically improved.

“The concept of mimicking natural control of the ankle is very straightforward,” Huang said. “But implementation of this concept is more complicated. It requires training people to use residual muscles to drive new prosthetic technologies. The results in this case study were dramatic. This is just one study, but it shows us what is feasible.”

“There is also a profound emotional impact when people use powered prosthetic devices that are controlled by reading the electrical signals that their bodies are making,” Fleming said. “It is much more similar to the way people move intuitively, and that can make a big difference in how people respond to using a prosthesis at all.”

More participants are already undergoing the training, with the researchers expanding their testing to match. But before this technology is made more widely available, the researchers would like real-world testing, with the prosthesis being used in people’s daily routines.

“As with any prosthetic device for lower limbs, you have to make sure the device is consistent and reliable, so that it doesn’t fail when people are using it,” Huang said.

“Powered prostheses that exist now are very expensive and are not covered by insurance,” Fleming explained. “So there are issues related to access to these technologies. By attempting to restore normal control of these type of activities, this technology stands to really improve quality of life and community participation for individuals with amputation. This would make these expensive devices more likely to be covered by insurance in the future if it means improving the overall health of the individual.”

The researchers are currently working with a larger group of study participants to see how broadly applicable the findings may be.

Source: News-Medical.Net

Journal information: Fleming, A., et al. (2021) Direct continuous electromyographic control of a powered prosthetic ankle for improved postural control after guided physical training: A case study. Wearable Technologies. doi.org/10.1017/wtc.2021.2.

Categories : NeurologyTags :

Chronic Sinusitis Linked to Neural Functions

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A small proof-of-concept study found that sinonasal inflammation was associated with neural changes that could precede cognitive symptoms in young people.

In comparison to healthy controls, people with chronic rhinosinusitis showed decreased functional connectivity within the frontoparietal network, a major cognition modulating hub, in resting-state functional MRI imaging. The frontoparietal network allows individuals to coordinate behaviour in a rapid, accurate, and flexible goal-driven manner.

These individuals also had greater connectivity of this region to the default mode network (areas that are activated during introspective and self-referential processing) and decreased connectivity to the salience network (areas involved in detection and response to stimuli) on brain imaging, reported Aria Jafari, MD, of University of Washington in Seattle, and colleagues.

Compared to controls, individuals with more severe rhinosinusitis inflammation tended to have greater differences in functional connectivity, Dr Jafari and colleagues stated. 

“Although definitive conclusions are not possible given the limitations inherent in the data set, including lack of rhinosinusitis-specific clinical information, our results present initial evidence for functional connectivity alterations as a potential basis for cognitive impairments seen in patients affected by chronic rhinosinusitis and may help direct future research,” Dr Jafari and colleagues said.

However, in this study, no cognitive deficits accompanied the functional connectivity changes. People with chronic rhinosinusitis and their matched controls shared similar cognitive status and similar sleep quality, with no between-group differences in olfaction, taste, and pain, either.

It was suggested by the researchers that, “given the brain’s ability to adapt and compensate, particularly in young and cognitively healthy individuals, our findings may represent early and subclinical functional brain alterations that may precede or be more sensitive than anticipated behavioral responses.”

“It is possible that a clinical chronic rhinosinusitis cohort with broader age distribution and more significant symptoms may have even greater changes in functional brain connectivity in the regions identified in this study,” they added.

“Overall, I do think that this study gives credence to the large body of evidence that patients with chronic rhinosinusitis, or in this case sinonasal inflammation, do have issues with cognition,” commented Nicholas Rowan, MD, of Johns Hopkins University School of Medicine in Baltimore, who was not part of the study.

Sinonasal inflammation and chronic rhinosinusitis have well established negative impacts on quality of life, according to Rowan. Previous research has found that medical or surgical intervention for chronic rhinosinusitis can alleviate cognitive dysfunction.

“Though unfortunately, the findings here are not actionable from a clinical standpoint, they do provide novel information for further prospective study of patients with chronic rhinosinusitis, as well as laboratory studies that are aimed to better understand the mechanism of why patients with CRS have such substantial quality of life implications,” according to Dr Rowan.

Although comorbid psychiatric disorders and sleep dysfunction are among the proposed mechanisms for cognitive dysfunction, the researchers said their data was supportive of a direct association of immune molecules with brain function.

Using data from The Human Connectome Project, the case-control study included 22 people with radiologic sinonasal inflammation who were matched 1:1 by age and sex to healthy controls. Sinonasal inflammation was classified as moderate in 13 people and severe in nine.

All were young adults age 22 to 35, and 68% were male.

Limitations included the retrospective nature of the study and the small sample size. Since cognitively normal participants identified radiographically from a large database, this limited the generalisability of the results, the authors added.

“Future prospective studies are warranted to determine the applicability of these findings to a clinical chronic rhinosinusitis population,” they said.

Source: MedPage Today

Journal information: Jafari A, et al “Association of sinonasal inflammation with functional brain connectivity” JAMA Otolaryngal Head Neck Surg 2021; DOI: 10.1001/jamaoto.2021.0204.

Categories : Injury & Trauma NeurologyTags :

Brain Glue Heals Neural Damage from Brain Injuries

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In a new study, researchers at the University of Georgia’s (UGA) Regenerative Biosciences Center have shown that the “brain glue” they developed protects against loss of brain tissue after a severe injury, and may also help in functional neural repair.

Significant traumatic brain injury (TBI) commonly results in extensive tissue loss and long-term disability, with no clinical treatments available to prevent this.

The new finding is the first to provide visual and functional evidence of the repair of brain neural circuits involved in reach-to-grasp movement in brain glue-implanted animals following severe TBI.

“Our work provides a holistic view of what’s going on in the recovery of the damaged region while the animal is accomplishing a specific reach-and-grasp task,” said lead investigator Lohitash Karumbaiah, an associate professor in the University of Georgia’s College of Agricultural and Environmental Sciences.

The brain glue developed by Prof Karumbaiah was designed to mimic the meshwork of sugars supporting brain cells. The hydrogel contains key structures that bind to two protective protein factors that can enhance the survival and regrowth of brain cells after severe TBI: basic fibroblast growth factor and brain-derived neurotrophic factor.

In previous research, Prof Karumbaiah and his team demonstrated that the brain glue conferred significant protection to brain tissue from severe TBI damage. In order to tap the neuroprotective capability of the original, they changed the delivery surface of protective factors to help accelerate the regeneration and functional activity of brain cells.

“Animal subjects that were implanted with the brain glue actually showed repair of severely damaged tissue of the brain,” said Karumbaiah. “The animals also elicited a quicker recovery time compared to subjects without these materials.”

The team used a tissue-cleaning method to make the brain less opaque, allowing them to 3-D image the cells’ response in the reach-to-grasp circuit, which is similar in rats and humans.

“Because of the tissue-clearing method, we were able to obtain a deeper view of the complex circuitry and recovery supported by brain glue,” said Prof Karumbaiah. “Using these methods along with conventional electrophysiological recordings, we were able to validate that brain glue supported the regeneration of functional neurons in the lesion cavity.”

“Doing the behavioral studies, the animal work and the molecular work sometimes takes a village,” said Karumbaiah. “This research involved a whole cross-section of RBC undergraduate and graduate students, as well as faculty members from both UGA and Duke University.”

Source: Medical Xpress

Journal information: Charles-Francois V. Latchoumane et al. Engineered glycomaterial implants orchestrate large-scale functional repair of brain tissue chronically after severe traumatic brain injury, Science Advances (2021). DOI: 10.1126/sciadv.abe0207

Categories : NeurologyTags :

Shared Neural System May Be Used for Different Memory Stores

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The brain may have a shared neural system that is involved in the retrieval of facts and personal memories used in everyday life, new research has found.

Factual memory had long been categorised into two stores; factual memory and memory of personal experiences. These two repositories in concert enable people to make sense of the world around them. Individuals with retrograde amnesia can fail to remember personal experiences, but still recall factual knowledge. These two stores have been shown by decades of clinical and experimental research to be stored across two separate regions of the brain.

But the new study suggests that a shared set of brain regions play an important role in controlling the successful retrieval of weak memories.

When participants were asked to retrieve fact memories and personal memories, researchers used functional MRI imaging to study how these regions changed in activity levels.

Lead researcher Dr Deniz Vatansever, formerly of the University of York and now working for the Institute of Science and Technology for Brain-inspired Intelligence, Fudan University said: “The new research suggests that despite their functional differences, successfully retrieving weak information from these two memory systems might be dependent upon a shared brain mechanism.

“Our memories allow us to make sense and flexibly interact with the world around us. Although in most cases, our strongly encoded memories might be sufficient for the task at hand, remembering to pack a beach towel for an upcoming seaside holiday, this strong memory may be irrelevant in other instances, such as when packing for a business trip. As such, we need to tightly control the retrieval of relevant memories to solve different tasks under different circumstances. Our results indicate that this control process might be shared across both factual and personal memory types.”

The researchers said their findings may be applicable to memory disorders, including dementia, where patients’ quality of life is affected by being unable to remember important information. The findings could also be relevant in the development of a new generation of AI, which use long-term memory in solving computational problems. 

“In order to generate appropriate thoughts and behaviors, we have to draw on our memory stores in a highly flexible way,” said senior author Elizabeth Jefferies, and professor, Department of Psychology, University of York. “This new study highlights control processes within the brain that allow us to focus on unusual aspects of the meanings of words and to retrieve weakly encoded personal experiences. This control over memory allows us to be creative and to adapt as our goals or circumstances change.”

Source: News-Medical.Net

Journal information: Vatansever, D., et al. (2021) Varying demands for cognitive control reveals shared neural processes supporting semantic and episodic memory retrieval. Nature Communications. doi.org/10.1038/s41467-021-22443-2.

Categories : NeurologyTags :

Sugar-sweetened Drinks During Adolescence Impacts Cognition in Adulthood

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New research has shown that, in rats, daily consumption of sugar-sweetened drinks during adolescence impairs performance on a learning and memory task during adulthood. 

The researchers also demonstrated that changes in the bacteria in the gut may be the key to the sugar-induced memory impairment. Evidence in support of this comes from the observation of similar memory deficits even when the bacteria, called Parabacteroides, were experimentally enriched in the guts of animals that had never consumed sugar.

“Early life sugar increased Parabacteroides levels, and the higher the levels of Parabacteroides, the worse the animals did in the task,” said first author Emily Noble, assistant professor, College of Family and Consumer Sciences, University of Georgia. “We found that the bacteria alone was sufficient to impair memory in the same way as sugar, but it also impaired other types of memory functions as well.”

Data from the Centers for Disease Control and Prevention show American children between the ages 9-18 exceed the recommendation of limiting added sugars to less than 10 percent of calories per day, with the bulk of the calories coming from sugar-sweetened beverages.

Since the hippocampus is still developing into late adolescence and plays a role in a variety of cognitive functions, researchers sought to understand more about its susceptibility to a high-sugar diet via gut microbiota.

Juvenile rats were given their normal chow and an 11% sugar solution, comparable to commercially available sugar-sweetened beverages. Researchers then had the rats perform a hippocampus-dependent memory task designed to measure episodic contextual memory, or remembering the context where they had seen a familiar object before.

“We found that rats that consumed sugar in early life had an impaired capacity to discriminate that an object was novel to a specific context, a task the rats that were not given sugar were able to do,” Prof Noble said.

A second memory task measured basic recognition memory, a hippocampal-independent memory function that involves the animals’ ability to recognise something they had seen previously. Sugar had no effect on the animals’ recognition memory.

“Early life sugar consumption seems to selectively impair their hippocampal learning and memory,” Prof Noble said.

Further analysis revealed that high sugar consumption led to elevated levels of Parabacteroides in the gut microbiome, the more than 100 trillion microorganisms in the gastrointestinal tract that play a role in human health and disease.

To determine the mechanism by which bacteria impacted memory and learning, researchers experimentally increased levels of Parabacteroides in the microbiome of rats that had never consumed sugar. Those animals showed impairments in both hippocampal dependent and hippocampal-independent memory tasks.

“(The bacteria) induced some cognitive deficits on its own,” Prof Noble said.

Future research is needed to better identify these gut-brain signaling specific pathways.

“The question now is how do these populations of bacteria in the gut alter the development of the brain?” Prof Noble said. “Identifying how the bacteria in the gut are impacting brain development will tell us about what sort of internal environment the brain needs in order to grow in a healthy way.”

Source: News-Medical.Net

Journal information: Noble, E. E., et al. (2021) Gut microbial taxa elevated by dietary sugar disrupt memory function. Translational Psychiatry. doi.org/10.1038/s41398-021-01309-7.

Categories : NeurologyTags :

‘Zombie’ Genes Lurch into Activity After Brain Death

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Researchers have found that genes in cells in recently harvested brain tissue remained active for up to 24 hours – and some ‘zombie’ genes even increased their expression.

Using recently harvested brain tissue as a surrogate for actual death, the researchers investigated the activity of genes.

Dr Jeffrey Loeb, the John S Garvin Professor and head of neurology and rehabilitation at the UIC College of Medicine and corresponding author on the paper, noticed along with his team that the pattern of gene expression in fresh human brain tissue differed from published reports of postmortem brain gene expression from people without neurological disorders or from people with a wide variety of neurological disorders, ranging from autism to Alzheimer’s.

“We decided to run a simulated death experiment by looking at the expression of all human genes, at time points from zero to 24 hours, from a large block of recently collected brain tissues, which were allowed to sit at room temperature to replicate the postmortem interval,” Dr Loeb said.

They found that some ‘zombie’ genes were more expressed after the simulated death. These were specific to glial cells, which have an inflammatory role. The researchers observed that these cells continued to grow long arm-like appendages for many hours after death.

“That glial cells enlarge after death isn’t too surprising given that they are inflammatory and their job is to clean things up after brain injuries like oxygen deprivation or stroke,” said Dr Loeb.

Dr Loeb is director of the UI NeuroRepository, which preserves human brain tissues from patients with neurological disorders who gave their consent to use their tissue after death, or during surgery to treat disorders such as epilepsy, where some brain tissue is removed to treat the condition in lesionectomy. This procedure involves removing structural brain lesions — typically malformations of cortical development, low-grade neoplasms, or vascular malformations. Some of the tissue harvested through these various means can be used for research, as in this study.

About 80% of genes, many of which are involved in cellular ‘housekeeping’ activities, kept functioning up to 24 hours after death. Another group of genes involved in cognition and seizure control faded within a few hours of death. These are important to the study of schizophrenia and Alzheimer’s disease, according to Dr Loeb.

The ‘zombie’ genes ramped up activity as the others were winding down, with these changes peaking at 12 hours.

“Our findings don’t mean that we should throw away human tissue research programs, it just means that researchers need to take into account these genetic and cellular changes, and reduce the post-mortem interval as much as possible to reduce the magnitude of these changes,” Dr Loeb said. “The good news from our findings is that we now know which genes and cell types are stable, which degrade, and which increase over time so that results from postmortem brain studies can be better understood.”

Source: Medical Xpress

Journal information: Fabien Dachet et al. Selective time-dependent changes in activity and cell-specific gene expression in human postmortem brain, Scientific Reports (2021). DOI: 10.1038/s41598-021-85801-6

Categories : Neurology PaediatricsTags :

Boy’s Brain Rewires After Stroke as a Newborn

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Photo by cottonbro from Pexels

Researchers have reported the case of a boy whose brain was able to rewire after a severe stroke that damaged much of his brain.

In the seventh grade, 13-year old Daniel Carr amazed his baseball coach with his ability to throw with his left hand, saying that it was the fastest he’d ever seen. However, he was unable to properly catch with his right hand.

Hearing this from the coach, Kellie Carr, Daniel’s mother, realised that his son had a number of quirks, such as favouring his left side when he was an infant, and his left-handedness emerged well before the normal age of two or three. However, she was unable to get any explanation for this until she met Nico Dosenbach, MD, PhD, who informed her that her son had had a stroke when he was a newborn.

MRI scans revealed large, bilateral voids in Daniel’s brain, but incredibly, he had no cognitive, behavioural or motor problems other than a lack of strength and dexterity in his right arm.
“The extent of Daniel’s injuries may be on the edge of what’s compatible with life,” Dosenbach said.

Dainel’s remarkable recovery can be explained by his young age at the time the stroke.

“The brain can compensate more quickly and completely for strokes sustained in early childhood,” he said. “By contrast, large strokes in adults often cause death or severe functional impairment with little chance of recovery. However, the mechanics behind this are only beginning to be understood.”

More MRI scans were done on Daniel’s brain to determine its structure and pathology. Dosenbach and Laumann conducted high-resolution functional MRI scans to understand how Daniel’s brain had reorganised itself.
With his mother’s consent, Daniel was further tested over a period of six years, including batteries of neurological tests, and more scans done. Timothy Laumann, MD, PhD, now a fourth-year psychiatry resident at Barnes-Jewish Hospital, had the expertise to analyse the data.

Looking at his medical records, the physician-scientists noted that he had an infection as a newborn, and was hospitalised with an IV drip. However, none of the physicians had suspected a stroke, which happens to one in every 4000 newborns. Daniel was sent home after a week, the doctors having suspected a viral infection.

“The risk of having a pediatric stroke greatly increases with a medical problem, especially an infection during the newborn period,” Dosenbach said. “However, usually there are more obvious signs that a stroke occurred. I can understand how no one suspected it.”

The researchers compared the images of Daniel’s brain to others of young adults, as well as Dosenbach’s own brain, which he had imaged and studied extensively.

“Part of Daniel’s brain structure is gone,” Laumann explained, referring to their analysis of the MRI data. “He’s missing almost a quarter of his cortex.”

The dead tissue was replaced by pockets of cerebrospinal fluid, which acts as a shock absorber, as well as delivering nutrients and removing waste. The surviving neurons formed interconnected islands that restored cognitive and motor functions, and neighbourhoods of healthy tissue were again reconnected.

“Our findings illustrate the brain’s tenacity at reorganizing and recovering functions damaged by a massive stroke affecting both sides of his brain,” Dosenbach said. “Future studies of functional remapping relative to tissue loss may provide additional insights. Our results raise the possibility that variability in outcomes may depend on specific features unique to an individual’s brain.”

Despite the extensive damage, Daniel completed tertiary education and now works as a diesel mechanic.

“His stroke still shocks me,” Kellie Carr said. “How could I have not known? But looking back, maybe it was better that way. I might have babied Daniel and been afraid to let him be a regular kid. Maybe the best thing for him was living normally.”

Daniel agreed: “I think about my right hand daily because I have to constantly think five steps ahead to figure out how to compensate for not being able to use it properly, like I did with the baseball glove. But the last thing I want is for people to act like something is wrong with me. I’m fine.”

Source: Medical Xpress

Journal information: Timothy O Laumann et al. Brain network reorganisation in an adolescent after bilateral perinatal strokes, The Lancet Neurology (2021). DOI: 10.1016/S1474-4422(21)00062-4

Categories : Pain ManagementTags :

Dopamine Affects Pain Differently in Female and Male Mice

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Researchers have found that dopamine affects the neurons of male and female mice in different ways, a discovery which could have great potential in pain management for women, who suffer pain disproportionately throughout their lives.

Dopamine, popularly known as the brain’s ‘pleasure chemical’, is implicated in many functions, including the reward pathways and also the pain-relieving pathways associated with heroin that the researchers were focussing on. Dopamine is also suggested to be involved in attention, suggesting a link between substance abuse, pain and attention.

“We focused on this neural pathway because our previous work and that of others show that specific neurons release dopamine to regulate pain responses,” explained Thomas Kash, PhD, the John R Andrews Distinguished Professor of Pharmacology, School of Medicine lab, University of North Carolina. “Unfortunately, that research was done only in male mice. So we decided to look at both male and female mice, and what we found was very surprising.”

Previous research from Dr Kash’s lab using male mice showed that dopaminergic neurons were key in how opiates dampen pain, likely through dopamine and glutamate release. The new experiments focussed on a neural pathway starting at the midbrain region called the periaqueductal grey, including part of the dorsal raphe.

This brain region is involved in behavioural adaptation, which is the way animals respond to their environment. The dopamine-producing neurons in this region form a neural pathway with a structure known as the bed nucleus of the stria terminalis (BNST). 

“We found that activating this pathway reduced pain sensitivity in male mice, but made female mice move more, especially in the presence of something capturing their attention,” said first author Waylin Yu, PhD, a former graduate student in the Kash lab and current postdoctoral researcher at UC San Francisco. “We think this is because of the different ways males and females respond to pain.”

This seems to indicate that dopamine helps male mice simply not feel as much pain, while female mice are able to focus their attention elsewhere while experiencing pain.

While further investigation is needed, the results appear to show that the activation of specific neural projections to the BNST reduces acute and persistent inflammatory pain. This adds to the evidence that dopamine signaling can enhance the blocking of pain stimuli, counteracting severe pain.

“We hope to investigate how this pathway can regulate more emotional behaviours associated with chronic pain, and then also look at the dynamics of the system, such as how this pathway works in real time during behaviour measurements,” Dr Kash said. “These neurons are also implicated in the actions of opioids such as morphine, so we plan to investigate that domain, as well.”

Source: News-Medical.Net

Categories : Ageing NeurologyTags :

Jump-Starting Neural Stem Cells in Aged Brains

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As we age, neural stem cells lose the ability to divide and create new neurons, resulting in a decline in memory. Now, research led by Sebastian Jessberger, a professor at the Brain Research Institute of the University of Zurich, explains why this happens.

The new neurons are used all over the brain, including the hippocampus which is responsible for memory. Declines here from age and Alzheimer’s mean fewer neurons are produced here, impacting memory functions.

“As we get older, stem cells throughout the body gradually lose their ability to proliferate. Using genetic engineering and cutting-edge microscope technology, we were able to identify a mechanism that is associated with this process,” explained doctoral candidate and first author Khadeesh bin Imtiaz. The results were published in the journal Cell Stem Cell.

The study used a mouse model to show that as organisms age, neurons’ ability to divide becomes impaired. Protein structures ensure that accumulated harmful proteins are laid out unequally among the two daughter neurons, important for the longevity of neurons. As the neurons age, the amount of nucleic proteins changes, resulting in impaired distribution of proteins, reducing the number of newly generated neurons in the brains of older mice.

The researchers identified a nuclear protein called lamin B1, levels of which decrease as people age. When lamin B1 was increased in aged mice, there was an improvement in stem cell division and the number of neurons increased.

The study was part of wider research into ageing and stem cells. “While our study was limited to brain stem cells, similar mechanisms are likely to play a key role when it comes to the ageing process of other stem cells,” said Prof Jessberger.

The latest findings represent an important step in understanding how brain stem cells change with age. “We now know that we can reactivate aging stem cells in the brain. Our hope is that these findings will one day help increase levels of neurogenesis, for example in older people or those suffering from degenerative diseases such as Alzheimer’s. Even if this may still be many years in the future,” concluded Prof Jessberger.

Source: Medical Xpress

Journal information: Cell Stem Cell, DOI: 10.1016/j.stem.2021.01.015