A measurable dip in brain choline may be one of the clearest chemical markers linked to anxiety disorders.
Category: neuroscience – Page 18
Study reveals visual processing differences in dyslexia extend beyond reading
New research published in Neuropsychologia provides evidence that adults with dyslexia process visual information differently than typical readers, even when viewing non-text objects. The findings suggest that the neural mechanisms responsible for distinguishing between specific items, such as individual faces or houses, are less active in the dyslexic brain. This implies that dyslexia may involve broader visual processing differences beyond the well-known difficulties with connecting sounds to language.
Dyslexia is a developmental condition characterized by significant challenges in learning to read and spell. These difficulties persist despite adequate intelligence, sensory abilities, and educational opportunities. The most prominent theory regarding the cause of dyslexia focuses on a phonological deficit. This theory posits that the primary struggle lies in processing the sounds of spoken language.
According to this view, the brain struggles to break words down into their component sounds. This makes mapping those sounds to written letters an arduous task. However, reading is also an intensely visual activity. The reader must rapidly identify complex, fine-grained visual patterns to distinguish one letter from another.
From mind-controlling tech to clinical therapy
Researchers at the University of Geneva, together with colleagues in Switzerland, France, the United States and Israel, describe how optogenetic control of brain cells and circuits is already steering both indirect neuromodulatory therapies and first-in-human retinal interventions for blindness, while sketching the practical and ethical conditions needed for wider clinical use.
Optogenetic control uses light to impose temporally precise gain or loss of function in specific cell types, or even individual cells. Selected by location, connections, gene expression or combinations of these features, researchers now have an unprecedented way to investigate the brain within living animals.
Modern experiments range from implanted fiber optics to three-dimensional holographic illumination of defined neuronal ensembles and noninvasive wearable LEDs, with interventions that can run from milliseconds to chronic use and effect sizes that change rapidly with changes in light intensity.
A prospective study of minimally invasive keyhole craniotomy and stereotactic brachytherapy for new brain oligometastases
Mahapatra et al. show how minimally invasive keyhole craniotomy combined with brachytherapy provides strong local control for brain metastases, with no radiation necrosis and improved neurological and cognitive outcomes, highlighting this approach as a promising alternative to WBRT and SRS. JNOO
Read more here.
Metastatic brain tumors (MBTs) are the most common intracranial tumors, affecting up to 40% of cancer patients. Traditional treatments such as Whole Brain Radiotherapy (WBRT) and Stereotactic Radiosurgery (SRS) have limitations, including neurocognitive decline and potential tumor regrowth. Minimally invasive keyhole craniotomy (MIKC) and Cesium-131 (Cs-131) brachytherapy offer promising alternatives due to their precision and reduced side effects. This prospective study aims to evaluate the safety and efficacy of combining MIKC with Cs-131 brachytherapy in treating newly diagnosed brain oligometastases.
Twenty-one adults with newly diagnosed brain metastases were enrolled from 2019 to 2021. Preoperative T1 MRI with gadolinium was used to calculate the gross tumor volume (GTV). Minimally invasive craniotomies were performed with resection of these tumors, followed by the implantation of Cs-131 seeds. Postoperative imaging was conducted to verify seed placement and resection. Dosimetric values (V100, V200, D90) were calculated. Patients were followed every two months for two years to monitor local progression, functional outcomes, and quality of life. The primary endpoint was freedom from local progression, with secondary endpoints including overall survival, functional outcomes, quality of life, and treatment-related complications.
The median preoperative tumor volume was 10.65 cm3, reducing to a resection cavity volume of 6.05 cm3 post-operatively. Dosimetric analysis showed a median V100 coverage of 93.2%, V200 of 43.9%, and D90 of 89.8 Gy. The 1-year local freedom from progression (FFP) was 91.67%, while the distant FFP was 53.91%. Five patients remained alive at the study’s end, with a median survival duration of 5.9 months, a duration likely impacted by the concurrent COVID-19 pandemic. Only one patient experienced local recurrence, and no cases of radiation necrosis were observed. Significant improvements were seen in neurological, functional, and cognitive symptoms.
Molecular basis for de novo thymus regeneration in a vertebrate, the axolotl
In humans, the loss of thymic function through thymectomy, environmental challenges, or age-dependent involution is associated with increased mortality, inflammaging, and higher risk of cancer and autoimmune disease (1). This is largely due to a decline in the intrathymic naïve T cell pool, whose generation is orchestrated by the thymic stroma, particularly thymic epithelial cells (TECs) (2). Upon challenges that affect the TEC compartment, the thymus is capable of triggering an endogenous regenerative response by engaging resident epithelial progenitors with stem cell features (3–5). Yet, after age-related atrophy or thymectomy resulting from myasthenia gravis or tumor removal (1), this regenerative response is unable to overcome the loss of thymic tissue, highlighting the need for therapeutic interventions.
The restoration of thymic functionality has been achieved to a limited extent via strategies targeting the thymic epithelial microenvironment or hematopoietic progenitors, modulating hormones and metabolism, or through cellular therapies and bioengineering (6). In mice, the up-regulation of Foxn1, a key transcription factor for thymus development and organogenesis (7), either directly or via its upstream effector bone morphogenetic protein 4 (BMP4), can support activity of cortical TECs (cTECs) (8, 9). Further, a combination of growth hormone and metformin has been shown to restore thymic functional mass in humans (10). Nevertheless, such strategies only lead to delayed thymic involution, and examples of complete thymus regeneration have not yet been described among vertebrates.
Because of its remarkable regenerative abilities that extend to parts of the brain, eye, heart, and spinal cord, and even entire limbs, the axolotl (Ambystoma mexicanum) is a powerful model for regeneration studies (11). The axolotl has offered insights into the mechanisms of positional identity (12), cell plasticity (13, 14), and the molecular basis of complex regeneration (15–18). The regeneration of axolotl body parts relies on remnants of the missing structure, with the exception of lens tissue, which can regrow from dorsal pigmented epithelial cells during a short window during development (19). However, whether de novo regeneration can occur for an entire complex organ, in axolotls or any other vertebrate, is unknown.
Scientists Gave Human Brain Cells to a Rat. Why?
Scientists transplanted human cerebral organoids (“minibrains”) into rats, to better study brain disorders. The neurons grown in vivo looked more like mature human brain cells than those grown in vitro, and they made better models of Timothy syndrome. The human minibrains formed deep connections with the rat brains, received sensory information, and drove the rat’s behavior. Points of Clarification (Q&A based on common comments) Support the channel: / ihmcurious More on how minibrains are grown and used, and the issue of organoid consciousness:
• Growing “Mini-Brains” in a Lab: Human Brai… On the topic of organoid sentience and playing pong:
• Lab-Grown “Mini-Brain” Learns Pong — Is Th… Organoid transplant study: https://www.nature.com/articles/s4158… music by John Bartmann: https://johnbartmann.com
Cell-Based Neurodegenerative Disease Modeling
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive upper and lower motor neuron (MN) degeneration with unclear pathology. The worldwide prevalence of ALS is approximately 4.42 per 100,000 populations, and death occurs within 3–5 years after diagnosis. However, no effective therapeutic modality for ALS is currently available. In recent years, cellular therapy has shown considerable therapeutic potential because it exerts immunomodulatory effects and protects the MN circuit. However, the safety and efficacy of cellular therapy in ALS are still under debate. In this review, we summarize the current progress in cellular therapy for ALS. The underlying mechanism, current clinical trials, and the pros and cons of cellular therapy using different types of cell are discussed. In addition, clinical studies of mesenchymal stem cells (MSCs) in ALS are highlighted. The summarized findings of this review can facilitate the future clinical application of precision medicine using cellular therapy in ALS.
ALS is believed to result from a combination of genetic and environmental factors (Masrori and Van Damme 2020). ALS exists in two forms: familial ALS (fALS) and sporadic ALS (sALS). fALS exhibits a Mendelian pattern of inheritance and accounts for 5–10% of all cases. The remaining 90–95% of cases that do not have an apparent genetic link are classified as sALS (Kiernan et al., 2011). At the genetic level, more than 20 genes have been identified. Among them, chromosome 9 open reading frame 72 (C9ORF72), fused in sarcoma (FUS), TAR DNA binding protein (TARDBP), and superoxide dismutase 1 (SOD1) genes have been identified as the most common causative genes (Riancho et al., 2019). Beyond genetic factors, the diverse pathological mechanisms of ALS-associated neurodegeneration have been discussed (van Es et al., 2017). The clinical symptoms of ALS are heterogeneous, with main symptoms including limb weakness, muscle atrophy, and fasciculations involving both upper and lower MNs.
3D maps reveal hidden microenvironments shaping mouse brain connectivity
Recent technological and scientific advances have opened new possibilities for neuroscience research, which is in turn leading to interesting new discoveries. Over the past few years, many groups of neuroscientists worldwide have been trying to map the structure of the brain and its underlying regions with increasing precision, while also probing their involvement in specific mental functions.
As mapping the human brain in detail is often challenging and requires significant resources, many studies focus on other mammals, particularly mice or other rodents. Most mouse brain atlases delineated to date map the density of neurons or other brain cells (i.e., how many cells are packed in specific parts of the brain). In contrast, fewer works also tried to map the shape of neurons in the mouse brain and interactions between them.
Researchers at Fudan University and Southeast University recently set out to map dendrites (i.e., branch-like extensions of neurons via which they receive signals from other cells) in the mouse brain. Their paper, published in Nature Neuroscience, unveils groups of structures in the mouse brain that influence how neurons function and connect to other neurons, also known as microenvironments.
How the cerebellum builds its connections with the rest of the brain during early development
For the first time, a team of researchers at the Institute for Neurosciences (IN), a joint center of the Spanish National Research Council (CSIC) and Miguel Hernández University of Elche (UMH), has reconstructed how the cerebellum establishes its connections with the rest of the brain during the earliest stages of life.
The work, published in the journal Proceedings of the National Academy of Sciences, describes in detail the phases during which these neural connections emerge, expand, and are refined, offering the first comprehensive map of the development of cerebellar projections across the mouse brain.
Although the cerebellum has traditionally been associated with motor control, growing evidence shows that it also plays a role in processes such as emotional regulation, social behavior, and other cognitive functions. However, until now, it was not precisely known when it began interacting with other regions of the brain, communication that is fundamental for these cerebellar roles. This gap motivated the work of the group Development, Wiring and Function of Cerebellar Circuits, led by Juan Antonio Moreno Bravo at the IN.