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Category: neuroscience

Single-cell resolution functional networks during unconsciousness are segregated into spatially intermixed modules

The common neural mechanisms underlying the reduction of consciousness during sleep and anesthesia remain unclear. Previous studies have examined changes in network structure by only using recordings with limited spatial resolution, which has hindered the investigation of the critical spatial scales for the reduction of consciousness. To address this issue, we recorded calcium signals from approximately 10,000 neurons across multiple cortical regions in awake, sleeping, and anesthetized mice and compared network structure at different spatial scales by leveraging single-cell resolution and wide-field two-photon microscopy. At the single-cell scale, both sleep and anesthesia exhibit higher network modularity than an awake state, indicating a segregated network, but modules are spatially intermixed in all three states.

Beyond the hours slept: inconsistent sleep routines threaten mental health in 100,000 UK Biobank participants

Sleep duration has a well-established effect on mental health and well-being, with durations of 7 to 9 hours being the general recommendation. Here, we analyze the significance of sleep patterns and find that a consistent routine reduces the risk of developing mental disorders far more than simply ensuring a certain average sleep duration.

We analyzed the sleep behavior of 100,000 adults for one week using motion data from wrist-worn devices. We modeled sleep behavior using multivariate generalized additive Cox proportional hazard models, incorporating a smooth 2D interaction effect of sleep duration and routine sleep hours. We calculated C-statistics and E-values to evaluate model performance and assess the robustness against hidden confounders. We also stratified analyses by age and gender.

Most participants slept for 7 to 9 hours as recommended, yet they consistently only slept during the same 4.8 hours each night. We found that an average sleep duration around 8 hours minimizes the risk of future mental disorders—but only if integrated into a rigorous sleep routine spanning at least the same 7 hours each night. Our study provides evidence that adopting such sleep behavior could reduce the population incidence rate of mental disorders by 23% (HR: 0.79, \(p0.0001\), for the average participant). The models showed a strong fit (C-statistics: 0.63), robustness to hidden confounders (E-value: 1.8), and stability under age-and gender-based stratification. We identified weekend behavior as a frequent reason for low sleep routines, with over 25% of the population disrupting their weekly sleep routine during weekend nights—raising the risk of future mental disorders by 10%.

What honey bee brain chemistry tells us about human learning

A multi-institutional team of researchers led by Virginia Tech’s Fralin Biomedical Research Institute at VTC has for the first time identified specific patterns of brain chemical activity that predict how quickly individual honey bees learn new associations, offering important insights into the biological basis of learning and decision-making. The study, published in Science Advances, found that the balance between the neurotransmitters octopamine and tyramine can predict whether a bee will learn quickly, slowly, or not at all, as they associate an odor with a reward.

Because the same ancient brain chemicals that guide learning in bees also shape attention and learning in people, the findings may help scientists better understand why individual humans learn at different speeds—and how those processes may go awry in a variety of brain disorders.

Specific patterns of brain chemical activity appear before learning begins and again when a learned behavior first emerges, signaling how quickly an individual bee will learn. The research can help explain how chemicals in the brain drive attention and reinforce learning, with implications for fundamental biology, medicine, and agriculture.

Common Sweetener May Damage Critical Brain Barrier, Risking Stroke

Found in everything from protein bars to energy drinks, erythritol has long been considered a safe alternative to sugar.

But research suggests this widely used sweetener may be quietly undermining one of the body’s most crucial protective barriers – with potentially serious consequences for heart health and stroke risk.

A study from the University of Colorado suggests erythritol may damage cells in the blood-brain barrier, the brain’s security system that keeps out harmful substances while letting in nutrients.

Cell Type-Specific Contributions of UBE3A to Angelman Syndrome Behavioral Phenotypes

ENeuro: Ringelberg et al. identify a key role for excitatory neuron loss of UBE3A in motor, innate, and sleep behavioral phenotypes of Angelman syndrome model mice.

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AS is a neurodevelopmental disorder with no disease-modifying treatment. However, clinical trials are currently underway using antisense oligonucleotides to unsilence the dormant paternal UBE3A allele, thereby normalizing UBE3A levels (Ionis: NCT05127226; Ultragenyx: NCT04259281). While this approach holds exciting promise and shows efficacy in mouse models (Meng et al., 2015; Milazzo et al., 2021), there is currently scant information regarding the key cell types or brain regions that require UBE3A reinstatement to mitigate core symptoms of AS. This holds particular importance, as effective biodistribution is a key concern in genetic therapies for CNS disorders (Roberts et al., 2020; Jafar-Nejad et al., 2021; Ling et al., 2023), and suboptimal targeting of necessary cell classes could hamper success. Moreover, mouse models of AS require early postnatal Ube3a reinstatement to achieve optimal phenotypic recovery (Silva-Santos et al., 2015; Sonzogni et al., 2020); early intervention could be difficult to achieve in the patient population without a corresponding early diagnosis, meaning many AS individuals are likely beyond the critical window to maximally benefit from UBE3A reinstatement-based therapies. Therefore, additional work is needed to better understand how loss of UBE3A leads to symptoms, as these insights will aid both in understanding the cell types that must be targeted for optimal genetic interventions and in developing alternative therapeutic options.

Our laboratory’s previous work identified an outsized role of GABAergic loss of UBE3A in hyperexcitability phenotypes. GABAergic loss of UBE3A drives increased delta power on cortical EEG (Judson et al., 2016), a phenotype that correlates with the severity of a range of symptoms in AS individuals (Hipp et al., 2021; Ostrowski et al., 2021). Further, mice with Ube3a deleted from GABAergic neurons show decreased threshold to chemically and acoustically driven seizures, and they also exhibit spontaneous behavioral seizures, a phenotype not observed in AS model mice on a C57BL/6J background (Judson et al., 2016; Gu et al., 2019). These data forewarn that UBE3A reinstatement in a manner biased to glutamatergic neurons could potentially worsen epilepsy-related symptoms and highlight the importance of studying the neuronal populations regulating other behaviors.

Based on the exaggerated role of GABAergic neurons in AS seizure phenotypes, we predicted that GABAergic deletion of Ube3a would underlie a broad range of behavioral phenotypes in AS mice. In the present study, we instead found a larger role of Ube3a deletion from glutamatergic neurons in motor coordination, measured by rotarod and open field behavior, and innate species-specific behaviors such as marble burying. Furthermore, glutamatergic loss of UBE3A appears to mediate alterations in sleep patterning and induces some sleep fragmentation, while UBE3A loss from GABAergic neurons only caused fragmented sleep. Interestingly, glutamatergic reinstatement of Ube3a also rescued the decreased REM sleep observed in AS mice, as estimated by the PiezoSleep system. While this study identified some roles of GABAergic neurons in nest building behavior and sleep fragmentation, our data largely suggest a divergence of the neural circuitry underlying the motor, innate behavior, and sleep phenotypes of AS mice from the circuitry responsible for seizure susceptibility and cortical EEG patterns.

Engineering chimeric antigen receptor CD4 T cells for Alzheimer’s disease

Recent advancements in immunotherapy have led to the first successful application of chimeric antigen receptor (CAR) T-cell therapy in treating neurodegenerative diseases, specifically Alzheimer’s disease. In a study conducted by researchers at Washington University in St. Louis and the Weizmann Institute of Science, T-cells were genetically engineered to recognize and target toxic beta-amyloid plaques. When tested on mouse models, three injections of these modified cells resulted in a significant reduction of protein aggregates within just ten days of the final administration. Beyond plaque clearance, the treatment successfully mitigated neuroinflammation, as evidenced by decreased microglial and astrocytic activity. These findings demonstrate the potential of CAR-T technology to rapidly clear pathological protein deposits and restore nervous tissue function, offering a promising new frontier for the treatment of Alzheimer’s and other proteinopathies.

Alzheimer’s disease (AD) is the prevailing cause of age-associated dementia worldwide. Current standard of care relies on antibody-based immunotherapy. However, antibody-based approaches carry risks for patients, and their effects on cognition are marginal. Increasing evidence suggests that T cells contribute to AD onset and progression. Unlike the cytotoxic effects of CD8+ cells, CD4+ T cells capable of regulating inflammation show promise in reducing pathology and improving cognitive outcomes in mouse models of AD and in aging. Here, we sought to exploit the beneficial properties of CD4+ T cells while circumventing the need for TCR and peptide-MHC antigen discovery, thereby providing a potential universal therapeutic approach. To achieve this, we engineered CD4+ T cells with chimeric antigen receptors (CARs) targeting fibrillar forms of aggregated amyloid-β. Our findings demonstrate that optimized CAR-T cells can alter amyloid deposition in the dura and reduce parenchymal pathology in the brain. Furthermore, we observed that CAR-T treatment promotes the expansion and recruitment of endogenous CD4+ T cells into the brain parenchyma and leptomeninges. In summary, we established the feasibility of amyloid plaque-specific CAR-T cells as a potential therapeutic avenue for AD. These findings highlight the potential of CD4+ CAR-T therapy not only to modify amyloid pathology but also to reshape the immune landscape of the CNS, paving the way for future development of cellular immunotherapies for neurodegenerative disease.

Keywords: Alzheimer’s disease; CAR T cells; T cell; chimeric antigen receptors; neurodegeneration.

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A single oncolytic virus injection may help T cells infiltrate glioblastoma

A team led by investigators at Mass General Brigham and Dana-Farber Cancer Institute has shown that a single injection of an oncolytic virus—a genetically modified virus that selectively infects and destroys cancer cells—can recruit immune cells to penetrate and persist deep within brain tumors. The research, which is published in Cell, provides details on how this therapy prolonged survival in patients with glioblastoma, the most common and malignant primary brain tumor, in a recent clinical trial.

“Patients with glioblastoma have not benefited from immunotherapies that have transformed patient care in other cancer types such as melanoma because glioblastoma is a ‘cold’ tumor with poor infiltration by cancer-fighting immune cells,” said co-senior author Kai Wucherpfennig, MD, Ph.D., chair of the Department of Cancer Immunology and Virology at the Dana-Farber Cancer Institute.

“Findings from our clinical trial and our mechanistic study show that it is now feasible to bring these critical immune cells into glioblastoma.”

A “dormant” brain protein turns out to be a powerful switch

Researchers at Johns Hopkins Medicine report that they have uncovered a promising drug target that could allow scientists to increase or decrease the activity of specific brain proteins. The discovery may lead to new treatments for psychiatric conditions such as anxiety and schizophrenia, as well as a neurological disorder that affects movement and balance. The work was supported by funding from the National Institutes of Health.

The proteins at the center of the research are known as delta-type ionotropic glutamate receptors, or GluDs. These proteins are known to play an important role in how neurons communicate with each other. According to the researchers, mutations in GluDs have been linked to psychiatric disorders, including anxiety and schizophrenia. Despite this connection, scientists have struggled for years to understand exactly how these proteins work, making it difficult to design treatments that could regulate their activity.

“This class of protein has long been thought to be sitting dormant in the brain,” says Edward Twomey, Ph.D., assistant professor of biophysics and biophysical chemistry at the Johns Hopkins University School of Medicine. “Our findings indicate they are very much active and offer a potential channel to develop new therapies.”

The Computer That Consumes Stars

And a black hole would be a type of computer if we could use it.

What is the ultimate limit of a civilization? It isn’t conquering a galaxy. It is processing power.

A “Matrioshka Brain” is a megastructure so massive it encases an entire star. It is a Dyson Sphere upgraded to God-Mode. Instead of just harvesting energy, it uses the star to fuel a computer powerful enough to simulate trillions of universes.

If a civilization builds one of these, they don’t need to explore space. They can upload their minds to a digital heaven and live forever. This might be the terrifying reason why the universe is so silent.

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