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2.
Health Informatics J ; 30(2): 14604582241260601, 2024.
Article in English | MEDLINE | ID: mdl-38838637

ABSTRACT

Virtual Reality (VR) offers cost-efficient and effective tools for spatial 3-dimensional neuroanatomy learning. Enhancing users-system relationship is necessary for successful adoption of the system. The current study aimed to evaluate students' acceptance of VR for neuroanatomy. An exploratory qualitative case study based on Unified Theory of Acceptance and Use of Technology (UTAUT) framework carried out at [details omitted for double-anonymized peer review]. Participants in this study were students participating in a VR session, followed by a semi-structured interview. Deductive framework analysis employed to retrieve students' perspective and experience. A total of six undergraduate and 13 postgraduate students participated in this study. The following UTAUT constructs validated to be significant: Performance Expectancy, Effort Expectancy and Facilitating Conditions. System usability, depth of lesson and hardware optimizations are among concern for further improvements. In conclusion, students are accepting VR as a neuroanatomy learning resource. The findings of this research highlight the importance of system performance and user-centred approach in technology development for educational purposes.


Subject(s)
Neuroanatomy , Qualitative Research , Virtual Reality , Humans , Neuroanatomy/education , Male , Female , Adult , User-Computer Interface , Interviews as Topic/methods , Students, Medical/psychology , Students, Medical/statistics & numerical data
3.
BMC Med Educ ; 24(1): 509, 2024 May 07.
Article in English | MEDLINE | ID: mdl-38715008

ABSTRACT

BACKGROUND: In this era of rapid technological development, medical schools have had to use modern technology to enhance traditional teaching. Online teaching was preferred by many medical schools. However due to the complexity of intracranial anatomy, it was challenging for the students to study this part online, and the students were likely to be tired of neurosurgery, which is disadvantageous to the development of neurosurgery. Therefore, we developed this database to help students learn better neuroanatomy. MAIN BODY: The data were sourced from Rhoton's Cranial Anatomy and Surgical Approaches and Neurosurgery Tricks of the Trade in this database. Then we designed many hand gesture figures connected with the atlas of anatomy. Our database was divided into three parts: intracranial arteries, intracranial veins, and neurosurgery approaches. Each section below contains an atlas of anatomy, and gestures represent vessels and nerves. Pictures of hand gestures and atlas of anatomy are available to view on GRAVEN ( www.graven.cn ) without restrictions for all teachers and students. We recruited 50 undergraduate students and randomly divided them into two groups: using traditional teaching methods or GRAVEN database combined with above traditional teaching methods. Results revealed a significant improvement in academic performance in using GRAVEN database combined with traditional teaching methods compared to the traditional teaching methods. CONCLUSION: This database was vital to help students learn about intracranial anatomy and neurosurgical approaches. Gesture teaching can effectively simulate the relationship between human organs and tissues through the flexibility of hands and fingers, improving anatomy interest and education.


Subject(s)
Databases, Factual , Education, Medical, Undergraduate , Gestures , Neurosurgery , Humans , Neurosurgery/education , Education, Medical, Undergraduate/methods , Students, Medical , Neuroanatomy/education , Teaching , Female , Male
4.
Prog Brain Res ; 285: 95-113, 2024.
Article in English | MEDLINE | ID: mdl-38705720

ABSTRACT

From the time of Hippocrates to the early 19th century, knowledge advanced but that was an uneven process. Anatomy was basically defined by Galen and remained cast in stone until the early 16th century. Neuroanatomy was described by Galen but had little practical value, as brain surgery was not possible. The anatomy of the cranium was known and was largely correct. Care was taken to avoid the frontal air sinuses and the venous sinuses and the temporal region. The role of the brain in consciousness was not understood. It was considered the seat of the soul but there was a lack of understanding that damage to it could induce clinical symptoms such as stupor or paralysis. These were variously attributed to injuries to the meninges or the bone. This error was finally corrected in the 18th century when the brain was identified as responsible for much of the clinical disturbance following cranial trauma. All awareness that post traumatic neurological deficit was contralateral was ignored until the late 18th century, although several authors noted it. Likewise, the presence of CSF had to wait until the 18th century until it was recognized. Fissures were treated with trepanation, because of a perceived risk of infection developing between the bone and the dura. Depressed fracture fragments were elevated, replaced, or removed according to the details of the injury. Finally, for centuries surgeons blocked patients ears to reduce the sound of drilling, despite the fact that such a blocking would amplify the noise.


Subject(s)
Brain , Humans , History, 19th Century , History, 18th Century , History, 16th Century , History, Ancient , History, 17th Century , History, 15th Century , History, Medieval , History, 20th Century , Neuroanatomy/history
6.
Sci Adv ; 10(22): eadk7220, 2024 May 31.
Article in English | MEDLINE | ID: mdl-38820151

ABSTRACT

Foundational mathematical abilities, acquired in early childhood, are essential for success in our technology-driven society. Yet, the neurobiological mechanisms underlying individual differences in children's mathematical abilities and learning outcomes remain largely unexplored. Leveraging one of the largest multicohort datasets from children at a pivotal stage of knowledge acquisition, we first establish a replicable mathematical ability-related imaging phenotype (MAIP). We then show that brain gene expression profiles enriched for candidate math ability-related genes, neuronal signaling, synaptic transmission, and voltage-gated potassium channel activity contributed to the MAIP. Furthermore, the similarity between MAIP gene expression signatures and brain structure, acquired before intervention, predicted learning outcomes in two independent math tutoring cohorts. These findings advance our knowledge of the interplay between neuroanatomical, transcriptomic, and molecular mechanisms underlying mathematical ability and reveal predictive biomarkers of learning. Our findings have implications for the development of personalized education and interventions.


Subject(s)
Brain , Learning , Mathematics , Transcriptome , Humans , Male , Female , Brain/metabolism , Learning/physiology , Child , Prognosis , Gene Expression Profiling , Neuroanatomy
7.
Methods Mol Biol ; 2757: 147-161, 2024.
Article in English | MEDLINE | ID: mdl-38668965

ABSTRACT

Ctenophores or comb jellies are representatives of an enigmatic lineage of early branching metazoans with complex tissue and organ organization. Their biology and even microanatomy are not well known for most of these fragile pelagic and deep-water species. Here, we present immunohistochemical protocols successfully tested on more than a dozen ctenophores. This chapter also illustrates neural organization in several reference species of the phylum (Pleurobrachia bachei, P. pileus, Mnemiopsis leidyi, Bolinopsis microptera, Beroe ovata, and B. abyssicola) as well as numerous ciliated structures in different functional systems. The applications of these protocols illuminate a very complex diversification of cell types comparable to many bilaterian lineages.


Subject(s)
Ctenophora , Immunohistochemistry , Animals , Ctenophora/anatomy & histology , Immunohistochemistry/methods , Neuroanatomy/methods
8.
Anat Sci Educ ; 17(4): 883-892, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38600432

ABSTRACT

Neuroanatomy is a notoriously challenging subject for medical students to learn. Due to the coronavirus disease-19 (COVID-19) pandemic, anatomical education transitioned to an online format. We assessed student performance in, and attitudes toward, an online neuroanatomy assessment compared to an in-person equivalent, as a marker of the efficacy of remote neuroanatomy education. Participants in the National Undergraduate Neuroanatomy Competition (NUNC) 2021 undertook two online examinations: a neuroanatomically themed multiple-choice question paper and anatomy spotter. Students completed pre- and post-examination questionnaires to gauge their attitudes toward the online competition and prior experience of online anatomical teaching/assessment. To evaluate performance, we compared scores of students who sat the online (2021) and in-person (2017) examinations, using 12 identical neuroradiology questions present in both years. Forty-six percent of NUNC 2021 participants had taken an online anatomy examination in the previous 12 months, but this did not impact examination performance significantly (p > 0.05). There was no significant difference in examination scores between in-person and online examinations using the 12 neuroradiology questions (p = 0.69). Fifty percent of participants found the online format less enjoyable, with 63% citing significantly fewer networking opportunities. The online competition was less stressful for 55% of participants. This study provides some evidence to suggest that student performance is not affected when undertaking online examinations and proposes that online neuroanatomy teaching methods, particularly for neuroradiology, may be equally as effective as in-person approaches within this context. Participants perceived online examinations as less stressful but raised concerns surrounding the networking potential and enjoyment of online events.


Subject(s)
COVID-19 , Education, Distance , Education, Medical, Undergraduate , Educational Measurement , Neuroanatomy , Neuroanatomy/education , Humans , Education, Distance/methods , Educational Measurement/statistics & numerical data , Education, Medical, Undergraduate/methods , Male , Female , Students, Medical/psychology , Students, Medical/statistics & numerical data , Surveys and Questionnaires , Pandemics , Young Adult , Adult , Curriculum
9.
Med Image Anal ; 95: 103182, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38688039

ABSTRACT

Recently, deep learning-based brain segmentation methods have achieved great success. However, most approaches focus on supervised segmentation, which requires many high-quality labeled images. In this paper, we pay attention to one-shot segmentation, aiming to learn from one labeled image and a few unlabeled images. We propose an end-to-end unified network that joints deformation modeling and segmentation tasks. Our network consists of a shared encoder, a deformation modeling head, and a segmentation head. In the training phase, the atlas and unlabeled images are input to the encoder to get multi-scale features. The features are then fed to the multi-scale deformation modeling module to estimate the atlas-to-image deformation field. The deformation modeling module implements the estimation at the feature level in a coarse-to-fine manner. Then, we employ the field to generate the augmented image pair through online data augmentation. We do not apply any appearance transformations cause the shared encoder could capture appearance variations. Finally, we adopt supervised segmentation loss for the augmented image. Considering that the unlabeled images still contain rich information, we introduce confidence aware pseudo label for them to further boost the segmentation performance. We validate our network on three benchmark datasets. Experimental results demonstrate that our network significantly outperforms other deep single-atlas-based and traditional multi-atlas-based segmentation methods. Notably, the second dataset is collected from multi-center, and our network still achieves promising segmentation performance on both the seen and unseen test sets, revealing its robustness. The source code will be available at https://github.com/zhangliutong/brainseg.


Subject(s)
Magnetic Resonance Imaging , Humans , Magnetic Resonance Imaging/methods , Deep Learning , Brain/diagnostic imaging , Image Processing, Computer-Assisted/methods , Algorithms , Neuroanatomy
10.
Brain Struct Funct ; 229(4): 971-985, 2024 May.
Article in English | MEDLINE | ID: mdl-38502332

ABSTRACT

Caviomorph rodents are an exceptional model for studying the effects of ecological factors and size relations on brain evolution. These mammals are not only speciose and ecologically diverse but also present wide body size disparity, especially when considering their fossil relatives. Here, we described the brain anatomy of the largest known rodent, Josephoartigasia monesi, uncovering distinctive features within this species regarding other taxa. Albeit resembling extant pacarana Dinomys branickii, J. monesi stands out due to its longer olfactory tract and well-developed sagittal sinus. Challenging the previous hypothesis that giant rodents possessed comparatively smaller brains, we found that J. monesi and another giant extinct rodent, Neoepiblema acreensis, are within the encephalization range of extant caviomorphs. This was unraveled while developing the a Phylogenetic Encephalization Quotient (PEQ) for Caviomorpha. With PEQ, we were able to trace brain-size predictions more accurately, accounting for species-shared ancestry while adding the extinct taxa phenotypic diversity into the prediction model. According to our results, caviomorphs encephalization patterns are not the product of ecological adaptations, and brain allometry is highly conservative within the clade. We challenge future studies to investigate caviomorphs encephalization within different taxonomic ranks while increasing the sampled taxa diversity, especially of extinct forms, in order to fully comprehend the magnitude of this evolutionary stasis.


Subject(s)
Biological Evolution , Rodentia , Animals , Rodentia/anatomy & histology , Phylogeny , Neuroanatomy , Mammals , Brain/anatomy & histology
11.
Adv Neurobiol ; 36: 141-147, 2024.
Article in English | MEDLINE | ID: mdl-38468030

ABSTRACT

The introduction of fractal geometry to the neurosciences has been a major paradigm shift over the last decades as it has helped overcome approximations and limitations that occur when Euclidean and reductionist approaches are used to analyze neurons or the entire brain. Fractal geometry allows for quantitative analysis and description of the geometric complexity of the brain, from its single units to the neuronal networks.As illustrated in the second section of this book, fractal analysis provides a quantitative tool for the study of the morphology of brain cells (i.e., neurons and microglia) and its components (e.g., dendritic trees, synapses), as well as the brain structure itself (cortex, functional modules, neuronal networks). The self-similar logic which generates and shapes the different hierarchical systems of the brain and even some structures related to its "container," that is, the cranial sutures on the skull, is widely discussed in the following chapters, with a link between the applications of fractal analysis to the neuroanatomy and basic neurosciences to the clinical applications discussed in the third section.


Subject(s)
Fractals , Neuroanatomy , Humans , Brain/physiology , Neurons
12.
J Neurosci Res ; 102(3): e25318, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38491847

ABSTRACT

The projections of the basal forebrain (BF) to the hippocampus and neocortex have been extensively studied and shown to be important for higher cognitive functions, including attention, learning, and memory. Much less is known about the BF projections to the basolateral nuclear complex of the amygdala (BNC), although the cholinergic innervation of this region by the BF is actually far more robust than that of cortical areas. This review will focus on light and electron microscopic tract-tracing and immunohistochemical (IHC) studies, many of which were published in the last decade, that have analyzed the relationship of BF inputs and their receptors to specific neuronal subtypes in the BNC in order to better understand the anatomical substrates of BF-BNC circuitry. The results indicate that BF inputs to the BNC mainly target the basolateral nucleus of the BNC (BL) and arise from cholinergic, GABAergic, and perhaps glutamatergic BF neurons. Cholinergic inputs mainly target dendrites and spines of pyramidal neurons (PNs) that express muscarinic receptors (MRs). MRs are also expressed by cholinergic axons, as well as cortical and thalamic axons that synapse with PN dendrites and spines. BF GABAergic axons to the BL also express MRs and mainly target BL interneurons that contain parvalbumin. It is suggested that BF-BL circuitry could be very important for generating rhythmic oscillations known to be critical for emotional learning. BF cholinergic inputs to the BNC might also contribute to memory formation by activating M1 receptors located on PN dendritic shafts and spines that also express NMDA receptors.


Subject(s)
Basal Forebrain , Basolateral Nuclear Complex , Neuroanatomy , Neurons/ultrastructure , Cholinergic Agents
13.
Hum Brain Mapp ; 45(4): e26640, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38445545

ABSTRACT

Voxel-based morphometry (VBM) and surface-based morphometry (SBM) are two widely used neuroimaging techniques for investigating brain anatomy. These techniques rely on statistical inferences at individual points (voxels or vertices), clusters of points, or a priori regions-of-interest. They are powerful tools for describing brain anatomy, but offer little insights into the generative processes that shape a particular set of findings. Moreover, they are restricted to a single spatial resolution scale, precluding the opportunity to distinguish anatomical variations that are expressed across multiple scales. Drawing on concepts from classical physics, here we develop an approach, called mode-based morphometry (MBM), that can describe any empirical map of anatomical variations in terms of the fundamental, resonant modes-eigenmodes-of brain anatomy, each tied to a specific spatial scale. Hence, MBM naturally yields a multiscale characterization of the empirical map, affording new opportunities for investigating the spatial frequency content of neuroanatomical variability. Using simulated and empirical data, we show that the validity and reliability of MBM are either comparable or superior to classical vertex-based SBM for capturing differences in cortical thickness maps between two experimental groups. Our approach thus offers a robust, accurate, and informative method for characterizing empirical maps of neuroanatomical variability that can be directly linked to a generative physical process.


Subject(s)
Brain , Neuroanatomy , Humans , Reproducibility of Results , Brain/diagnostic imaging , Head , Neuroimaging
14.
Nat Hum Behav ; 8(5): 962-975, 2024 May.
Article in English | MEDLINE | ID: mdl-38491094

ABSTRACT

Developmental language disorder (DLD) is a common neurodevelopmental disorder with adverse impacts that continue into adulthood. However, its neural bases remain unclear. Here we address this gap by systematically identifying and quantitatively synthesizing neuroanatomical studies of DLD using co-localization likelihood estimation, a recently developed neuroanatomical meta-analytic technique. Analyses of structural brain data (22 peer-reviewed papers, 577 participants) revealed highly consistent anomalies only in the basal ganglia (100% of participant groups in which this structure was examined, weighted by group sample sizes; 99.8% permutation-based likelihood the anomaly clustering was not due to chance). These anomalies were localized specifically to the anterior neostriatum (again 100% weighted proportion and 99.8% likelihood). As expected given the task dependence of activation, functional neuroimaging data (11 peer-reviewed papers, 414 participants) yielded less consistency, though anomalies again occurred primarily in the basal ganglia (79.0% and 95.1%). Multiple sensitivity analyses indicated that the patterns were robust. The meta-analyses elucidate the neuroanatomical signature of DLD, and implicate the basal ganglia in particular. The findings support the procedural circuit deficit hypothesis of DLD, have basic research and translational implications for the disorder, and advance our understanding of the neuroanatomy of language.


Subject(s)
Basal Ganglia , Language Development Disorders , Humans , Language Development Disorders/diagnostic imaging , Language Development Disorders/physiopathology , Basal Ganglia/diagnostic imaging , Brain/diagnostic imaging , Functional Neuroimaging , Neuroanatomy , Neostriatum/diagnostic imaging , Neostriatum/physiopathology , Neostriatum/pathology
15.
Hum Brain Mapp ; 45(4): e26639, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38433712

ABSTRACT

Multi-target attention, that is, the ability to attend and respond to multiple visual targets presented simultaneously on the horizontal meridian across both visual fields, is essential for everyday real-world behaviour. Given the close link between the neuropsychological deficit of extinction and attentional limits in healthy subjects, investigating the anatomy that underlies extinction is uniquely capable of providing important insights concerning the anatomy critical for normal multi-target attention. Previous studies into the brain areas critical for multi-target attention and its failure in extinction patients have, however, produced heterogeneous results. In the current study, we used multivariate and Bayesian lesion analysis approaches to investigate the anatomical substrate of visual extinction in a large sample of 108 acute right hemisphere stroke patients. The use of acute stroke patient data and multivariate/Bayesian lesion analysis approaches allowed us to address limitations associated with previous studies and so obtain a more complete picture of the functional network associated with visual extinction. Our results demonstrate that the right temporo-parietal junction (TPJ) is critically associated with visual extinction. The Bayesian lesion analysis additionally implicated the right intraparietal sulcus (IPS), in line with the results of studies in neurologically healthy participants that highlighted the IPS as the area critical for multi-target attention. Our findings resolve the seemingly conflicting previous findings, and emphasise the urgent need for further research to clarify the precise cognitive role of the right TPJ in multi-target attention and its failure in extinction patients.


Subject(s)
Neuroanatomy , Stroke , Humans , Bayes Theorem , Cerebral Cortex , Stroke/diagnostic imaging , Brain/diagnostic imaging
16.
Nat Commun ; 15(1): 2289, 2024 Mar 13.
Article in English | MEDLINE | ID: mdl-38480767

ABSTRACT

Deciphering the complex relationship between neuroanatomical connections and functional activity in primate brains remains a daunting task, especially regarding the influence of monosynaptic connectivity on cortical activity. Here, we investigate the anatomical-functional relationship and decompose the neuronal-tracing connectome of marmoset brains into a series of eigenmodes using graph signal processing. These cellular connectome eigenmodes effectively constrain the cortical activity derived from resting-state functional MRI, and uncover a patterned cellular-functional decoupling. This pattern reveals a spatial gradient from coupled dorsal-posterior to decoupled ventral-anterior cortices, and recapitulates micro-structural profiles and macro-scale hierarchical cortical organization. Notably, these marmoset-derived eigenmodes may facilitate the inference of spontaneous cortical activity and functional connectivity of homologous areas in humans, highlighting the potential generalizing of the connectomic constraints across species. Collectively, our findings illuminate how neuronal-tracing connectome eigenmodes constrain cortical activity and improve our understanding of the brain's anatomical-functional relationship.


Subject(s)
Callithrix , Connectome , Animals , Humans , Brain/diagnostic imaging , Brain/physiology , Neurons , Neuroanatomy , Magnetic Resonance Imaging
17.
Hippocampus ; 34(5): 241-260, 2024 May.
Article in English | MEDLINE | ID: mdl-38415962

ABSTRACT

The medial temporal lobe (MTL) cortex, located adjacent to the hippocampus, is crucial for memory and prone to the accumulation of certain neuropathologies such as Alzheimer's disease neurofibrillary tau tangles. The MTL cortex is composed of several subregions which differ in their functional and cytoarchitectonic features. As neuroanatomical schools rely on different cytoarchitectonic definitions of these subregions, it is unclear to what extent their delineations of MTL cortex subregions overlap. Here, we provide an overview of cytoarchitectonic definitions of the entorhinal and parahippocampal cortices as well as Brodmann areas (BA) 35 and 36, as provided by four neuroanatomists from different laboratories, aiming to identify the rationale for overlapping and diverging delineations. Nissl-stained series were acquired from the temporal lobes of three human specimens (two right and one left hemisphere). Slices (50 µm thick) were prepared perpendicular to the long axis of the hippocampus spanning the entire longitudinal extent of the MTL cortex. Four neuroanatomists annotated MTL cortex subregions on digitized slices spaced 5 mm apart (pixel size 0.4 µm at 20× magnification). Parcellations, terminology, and border placement were compared among neuroanatomists. Cytoarchitectonic features of each subregion are described in detail. Qualitative analysis of the annotations showed higher agreement in the definitions of the entorhinal cortex and BA35, while the definitions of BA36 and the parahippocampal cortex exhibited less overlap among neuroanatomists. The degree of overlap of cytoarchitectonic definitions was partially reflected in the neuroanatomists' agreement on the respective delineations. Lower agreement in annotations was observed in transitional zones between structures where seminal cytoarchitectonic features are expressed less saliently. The results highlight that definitions and parcellations of the MTL cortex differ among neuroanatomical schools and thereby increase understanding of why these differences may arise. This work sets a crucial foundation to further advance anatomically-informed neuroimaging research on the human MTL cortex.


Subject(s)
Temporal Lobe , Humans , Temporal Lobe/pathology , Neuroanatomy/methods , Male , Parahippocampal Gyrus/pathology , Parahippocampal Gyrus/diagnostic imaging , Female , Aged , Entorhinal Cortex/pathology , Entorhinal Cortex/anatomy & histology , Laboratories , Aged, 80 and over
18.
Elife ; 122024 Feb 06.
Article in English | MEDLINE | ID: mdl-38319699

ABSTRACT

Mapping the connectivity of diverse neuronal types provides the foundation for understanding the structure and function of neural circuits. High-throughput and low-cost neuroanatomical techniques based on RNA barcode sequencing have the potential to map circuits at cellular resolution and a brain-wide scale, but existing Sindbis virus-based techniques can only map long-range projections using anterograde tracing approaches. Rabies virus can complement anterograde tracing approaches by enabling either retrograde labeling of projection neurons or monosynaptic tracing of direct inputs to genetically targeted postsynaptic neurons. However, barcoded rabies virus has so far been only used to map non-neuronal cellular interactions in vivo and synaptic connectivity of cultured neurons. Here we combine barcoded rabies virus with single-cell and in situ sequencing to perform retrograde labeling and transsynaptic labeling in the mouse brain. We sequenced 96 retrogradely labeled cells and 295 transsynaptically labeled cells using single-cell RNA-seq, and 4130 retrogradely labeled cells and 2914 transsynaptically labeled cells in situ. We found that the transcriptomic identities of rabies virus-infected cells can be robustly identified using both single-cell RNA-seq and in situ sequencing. By associating gene expression with connectivity inferred from barcode sequencing, we distinguished long-range projecting cortical cell types from multiple cortical areas and identified cell types with converging or diverging synaptic connectivity. Combining in situ sequencing with barcoded rabies virus complements existing sequencing-based neuroanatomical techniques and provides a potential path for mapping synaptic connectivity of neuronal types at scale.


In the brain, messages are relayed from one cell to the next through intricate networks of axons and dendrites that physically interact at junctions known as synapses. Mapping out this synaptic connectivity ­ that is, exactly which neurons are connected via synapses ­ remains a major challenge. Monosynaptic tracing is a powerful approach that allows neuroscientists to explore neural networks by harnessing viruses which spread between neurons via synapses, in particular the rabies virus. This pathogen travels exclusively from 'postsynaptic' to 'presynaptic' neurons ­ from the cell that receives a message at a synapse, back to the one that sends it. A modified variant of the rabies virus can therefore be used to reveal the presynaptic cells connecting to a population of neurons in which it has been originally introduced. However, this method does not allow scientists to identify the exact postsynaptic neuron that each presynaptic cell is connected to. One way to bypass this issue is to combine monosynaptic tracing with RNA barcoding to create distinct versions of the modified rabies virus, which are then introduced into separate populations of neurons. Tracking the spread of each version allows neuroscientists to spot exactly which presynaptic cells signal to each postsynaptic neuron. So far, this approach has been used to examine synaptic connectivity in neurons grown in the laboratory, but it remains difficult to apply it to neurons in the brain. In response, Zhang, Jin et al. aimed to demonstrate how monosynaptic tracing that relies on barcoded rabies viruses could be used to dissect neural networks in the mouse brain. First, they confirmed that it was possible to accurately detect which version of the virus had spread to presynaptic neurons using both in situ and single-cell RNA sequencing. Next, they described how this information could be analysed to build models of potential neural networks, and what type of additional experiments are required for this work. Finally, they used the approach to identify neurons that tend to connect to the same postsynaptic cells and then investigated what these have in common, showing how the technique enables a finer understanding of neural circuits. Overall, the work by Zhang, Jin et al. provides a comprehensive review of the requirements and limitations associated with monosynaptic tracing experiments based on barcoded rabies viruses, as well as how the approach could be optimized in the future. This information will be of broad interest to scientists interested in mapping neural networks in the brain.


Subject(s)
Rabies virus , Animals , Mice , Rabies virus/genetics , Neuroanatomy , Neurons , Sequence Analysis, RNA , RNA
19.
Neuroimage ; 288: 120531, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38331333

ABSTRACT

Gait is an excellent indicator of physical, emotional, and mental health. Previous studies have shown that gait impairments in ageing are common, but the neural basis of these impairments are unclear. Existing methodologies are suboptimal and novel paradigms capable of capturing neural activation related to real walking are needed. In this study, we used a hybrid PET/MR system and measured glucose metabolism related to both walking and standing with a dual-injection paradigm in a single study session. For this study, 15 healthy older adults (10 females, age range: 60.5-70.7 years) with normal cognition were recruited from the community. Each participant received an intravenous injection of [18F]-2-fluoro-2-deoxyglucose (FDG) before engaging in two distinct tasks, a static postural control task (standing) and a walking task. After each task, participants were imaged. To discern independent neural functions related to walking compared to standing, we applied a bespoke dose correction to remove the residual 18F signal of the first scan (PETSTAND) from the second scan (PETWALK) and proportional scaling to the global mean, cerebellum, or white matter (WM). Whole-brain differences in walking-elicited neural activity measured with FDG-PET were assessed using a one-sample t-test. In this study, we show that a dual-injection paradigm in healthy older adults is feasible with biologically valid findings. Our results with a dose correction and scaling to the global mean showed that walking, compared to standing, increased glucose consumption in the cuneus (Z = 7.03), the temporal gyrus (Z = 6.91) and the orbital frontal cortex (Z = 6.71). Subcortically, we observed increased glucose metabolism in the supraspinal locomotor network including the thalamus (Z = 6.55), cerebellar vermis and the brainstem (pedunculopontine/mesencephalic locomotor region). Exploratory analyses using proportional scaling to the cerebellum and WM returned similar findings. Here, we have established the feasibility and tolerability of a novel method capable of capturing neural activations related to actual walking and extended previous knowledge including the recruitment of brain regions involved in sensory processing. Our paradigm could be used to explore pathological alterations in various gait disorders.


Subject(s)
Fluorodeoxyglucose F18 , Neuroanatomy , Female , Humans , Aged , Middle Aged , Gait/physiology , Walking/physiology , Positron-Emission Tomography/methods , Glucose/metabolism
20.
Int. j. morphol ; 42(1): 59-64, feb. 2024. tab
Article in Spanish | LILACS | ID: biblio-1528831

ABSTRACT

Las terminologías son utilizadas como instrumento lingüístico que permite la transmisión de conocimiento de manera precisa y sin ambigüedades en el ámbito de las ciencias. Los lineamientos de la Federative International Programme for Anatomical Terminology (FIPAT) refieren que la denominación de nombres estructurales debe ser descriptivos e informativos. Este estudio analiza las raíces lingüísticas que componen el término Neuron parvum valde fluorescens vigente en Terminologia Histologica y el término Neuron parvum fluorescens vigente en Terminologia Neuroanatomica. Las células pequeñas intensamente fluorescentes son neuronas que se encuentran en el sistema nervioso autónomo, distribuidas en los ganglios simpáticos. Estas células presentan sinapsis aferentes con terminales nerviosas simpáticas preganglionares y sinapsis eferentes con las dendritas de las neuronas posganglionares. Su función es regular la transmisión ganglionar, actuando como interneuronas con señalización paracrina y endocrina. Además, se caracterizan por ser células fluorescentes, que expresan catecolaminas; serotonina, noradrenalina y dopamina. Se realizó una búsqueda en Terminologia Histologica y Terminologia Neuroanatomica, con una traducción de los términos al español. Además, la búsqueda se complementó en un diccionario etimológico en inglés para los términos correspondientes. Esta investigación encontró diferencia entre la traducción del latín al español del término fluorescens, quien posee un origen etimológico muy diferente a su significado en español. El término Neuron parvum valde fluorescens en Terminologia Histologica y el término Neuron parvum fluorescens en Terminologia Neuroanatomica, identifican a la misma estructura. Se sugiere reemplazar ambos términos por Cateconeuron ganglionare, entregando así una correcta descripción de este tipo de neurona, considerando su ubicación y función. Además, de esta manera ser un término concordante en latín para su incorporación en Terminologia Neuroanatomica y Terminologia Histologica.


SUMMARY: Terminologies are used as a linguistic tool to convey knowledge in a precise and unambiguous manner in science. The guidelines of the Federative International Programme for Anatomical Terminology (FIPAT) state that the names given to structures should be both descriptive and informative. This study analyses the linguistic roots of the term Neuron parvum valde fluorescens in Terminologia Histologica and the term Neuron parvum fluorescens in Terminologia Neuroanatomica. Small intensely fluorescent cells are neurons found in the autonomic nervous system, distributed in the sympathetic ganglia, they have afferent synapses with preganglionic sympathetic nerve terminals and efferent synapses with the dendrites of postganglionic neurons, whose function is to regulate ganglionic transmission, acting as interneurons with paracrine and endocrine signalling. They are also characterized as fluorescent cells, producing the catecholamines: serotonin, noradrenaline and dopamine. A search was carried out in Terminologia Histologica and Terminologia Neuroanatomica, with a translation of the terms into Spanish. This was complemented by a search in an English etymological dictionary for the corresponding terms. This research found a difference between the Latin to English translation of the term fluorescens, which has a very different etymological origin to its English meaning. The term Neuron parvum valde fluorescens in Terminologia Histologica and the term Neuron parvum fluorescens in Terminologia Neuroanatomica identify the same structure. The proposal is to replace both terms with Cateconeuron ganglionare, thus affording an accurate description of this type of neuron, considering its location and function. Moreover, it would also be a concordant term in Latin for its incorporation into the Terminologia Neuroanatomica and Terminologia Histologica.


Subject(s)
Humans , Ganglia, Sympathetic/cytology , Histology , Neuroanatomy , Terminology as Topic
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