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The Journal of Comparative Neurology May 2021Primary mechanosensory neurons play an important role in converting mechanical forces into the sense of touch. In zebrafish, Rohon-Beard (RB) neurons serve this role at...
Primary mechanosensory neurons play an important role in converting mechanical forces into the sense of touch. In zebrafish, Rohon-Beard (RB) neurons serve this role at embryonic and larval stages of development. Here we examine the morphology and physiology of RBs in larval zebrafish to better understand how mechanosensory stimuli are represented along the spinal cord. We report that the morphology of RB neurons differs along the rostrocaudal body axis. Rostral RB neurons arborize in the skin near the cell body whereas caudal cells arborize at a distance posterior to their cell body. Using a novel electrophysiological approach, we also found longitudinal differences in the mechanosensitivity and physiological properties of RB neurons. Rostral RB neurons respond to mechanical stimulations close to the soma and produce up to three spikes with increasing stimulus intensity, whereas caudal cells respond at more distal locations and can produce four or more spikes when the intensity of the mechanical stimulus increases. The mechanosensory properties of RB neurons are consistent with those of rapidly adapting mechanoreceptors and can signal the onset, offset and intensity of mechanical stimulation. This is the first report of the intensity encoding properties of RB neurons, where an increase in spike number and a decrease in spike latency are observed with increasing stimulation intensity. This study reveals an unappreciated complexity of the larval zebrafish mechanosensory system and demonstrates how differences in the morphological and physiological properties of RBs related to their rostrocaudal location can influence the signals that enter the spinal cord.
Topics: Animals; Electrophysiology; Image Processing, Computer-Assisted; Mechanoreceptors; Spinal Cord; Zebrafish
PubMed: 32935362
DOI: 10.1002/cne.25033 -
NeuroImage. Clinical 2022Rugby players are subject to multiple impacts to their head and neck that could have adverse neurological effects and put them at increased risk of neurodegeneration....
Rugby players are subject to multiple impacts to their head and neck that could have adverse neurological effects and put them at increased risk of neurodegeneration. Previous studies demonstrated altered default mode network and diffusion metrics on brain, as well as more foraminal stenosis, disc protrusion and neck pain among players of contact sports as compared to healthy controls. However, the long-term effects of practice and repetitive impacts on brain and cervical spinal cord (cSC) of the rugby players have never been systematically investigated. In this study, 15 retired professional and amateur rugby players (R) and 15 age-matched healthy controls (HC) (all males; mean age R: 46.8 ± 7.6; and HC: 48.6 ± 9.5) were recruited both to investigate cord impairments and further characterize brain structure damage. Medical questionnaires including modified Japanese Orthopedic Association scale (mJOA) and Neck Disability Index (NDI) were filled by all participants. A 3 T multi-parametric MR protocol including conventional qualitative techniques such as T-, T-, and T*-weighted sequences, as well as state-of-the art quantitative techniques including MP2RAGE T mapping and 3D ihMTRAGE, was used on both brain and cSC. Normalized brain WM and GM volumes, spine Overall Stenosis Score, cord cross-sectional area and regional T and ihMT metrics were derived from these acquisitions. Rugby players showed significantly higher NDI scores, as well as a faster decline of normalized brain GM volume with age as compared to HC. Moreover, higher T values on cSC suggestive of structural degeneration, together with higher T and lower ihMTsat on brain WM suggestive of demyelination, were observed in retired rugby players as compared to age-matched controls, which may suggest cumulative effects of long-term impacts on the tissues. Metrics also suggest early aging and different aging processes on brain tissue in the players. These preliminary observations provide new insights in the domain, which should now be further investigated on larger cohorts and multicentric longitudinal studies, and further correlated to the likelihood of neurodegenerative diseases and risk factors.
Topics: Brain; Cervical Cord; Constriction, Pathologic; Humans; Male; Rugby; Spinal Cord
PubMed: 35905667
DOI: 10.1016/j.nicl.2022.103124 -
Neuroimaging Clinics of North America Feb 2024Primary angiitis of the central nervous system (PACNS) is a rare and potentially severe form of vasculitis that is limited to the brain, spinal cord, and meninges.... (Review)
Review
Primary angiitis of the central nervous system (PACNS) is a rare and potentially severe form of vasculitis that is limited to the brain, spinal cord, and meninges. Despite extensive research, the etiology and underlying immunologic mechanisms of PACNS remain largely unknown. PACNS presents with a variety of clinical, radiological, and pathologic features, but it is generally characterized by inflammation and destruction of the walls of blood vessels in the CNS, which can lead to tissue ischemia and/or hemorrhage. Three main histopathologic patterns have been identified, namely granulomatous, lymphocytic, and necrotizing vasculitis.
Topics: Humans; Vasculitis, Central Nervous System; Brain; Spinal Cord
PubMed: 37951703
DOI: 10.1016/j.nic.2023.06.002 -
International Journal of Molecular... Jan 2021In order for locomotion to occur, a complex pattern of muscle activation is required. For more than a century, it has been known that the timing and pattern of stepping... (Review)
Review
In order for locomotion to occur, a complex pattern of muscle activation is required. For more than a century, it has been known that the timing and pattern of stepping movements in mammals are generated by neural networks known as central pattern generators (CPGs), which comprise multiple interneuron cell types located entirely within the spinal cord. A genetic approach has recently been successful in identifying several populations of spinal neurons that make up this neural network, as well as the specific role they play during stepping. In spite of this progress, the identity of the neurons responsible for generating the locomotor rhythm and the manner in which they are interconnected have yet to be deciphered. In this review, we summarize key features considered to be expressed by locomotor rhythm-generating neurons and describe the different genetically defined classes of interneurons which have been proposed to be involved.
Topics: Animals; Humans; Interneurons; Locomotion; Muscle, Skeletal; Nerve Net; Spinal Cord
PubMed: 33573259
DOI: 10.3390/ijms22031394 -
Multiple Sclerosis and Related Disorders Jan 2022Magnetic resonance imaging (MRI) is a cornerstone in multiple sclerosis (MS) diagnostics and monitoring. Ultra-high field (UHF) MRI is being increasingly used and... (Review)
Review
Magnetic resonance imaging (MRI) is a cornerstone in multiple sclerosis (MS) diagnostics and monitoring. Ultra-high field (UHF) MRI is being increasingly used and becoming more accessible. Due to the small diameter and mobility of the spinal cord, imaging this structure at ultra-high fields poses additional challenges compared to brain imaging. Here we review the potential benefits for the MS field by providing a literature overview of the use UHF spinal cord MRI in MS research and we elaborate on the challenges that are faced. Benefits include increased signal- and contrast-to-noise, enabling for higher spatial resolutions, which can improve MS lesion sensitivity in both the spinal white matter as well as grey matter. Additionally, these benefits can aid imaging of microstructural abnormalities in the spinal cord in MS using advanced MRI techniques like functional imaging, MR spectroscopy and diffusion-based techniques. Technical challenges include increased magnetic field inhomogeneities, distortions from physiological motion and optimalisation of sequences. Approaches including parallel imaging techniques, real time shimming and retrospective compensation of physiological motion are making it increasingly possible to unravel the potential of spinal cord UHF MRI in the context of MS research.
Topics: Gray Matter; Humans; Magnetic Resonance Imaging; Multiple Sclerosis; Retrospective Studies; Spinal Cord
PubMed: 34871855
DOI: 10.1016/j.msard.2021.103436 -
Journal of Neurophysiology Sep 2022In vitro spinal cord preparations have been extensively used to study microcircuits involved in the control of movement. By allowing precise control of experimental...
In vitro spinal cord preparations have been extensively used to study microcircuits involved in the control of movement. By allowing precise control of experimental conditions coupled with state-of-the-art genetics, imaging, and electrophysiological techniques, isolated spinal cords from mice have been an essential tool in detailing the identity, connectivity, and function of spinal networks. The majority of the research has arisen from in vitro spinal cords of neonatal mice, which are still undergoing important postnatal maturation. Studies from adults have been attempted in transverse slices, however, these have been quite challenging due to the poor motoneuron accessibility and viability, as well as the extensive damage to the motoneuron dendritic trees. In this work, we describe two types of coronal spinal cord preparations with either the ventral or the dorsal horn ablated, obtained from mice of different postnatal ages, spanning from preweaned to 1 mo old. These semi-intact preparations allow recordings of sensory-afferent and motor-efferent responses from lumbar motoneurons using whole cell patch-clamp electrophysiology. We provide details of the slicing procedure and discuss the feasibility of whole cell recordings. The in vitro dorsal and ventral horn-ablated spinal cord preparations described here are a useful tool to study spinal motor circuits in young mice that have reached the adult stages of locomotor development. In the past 20 years, most of the research into the mammalian spinal circuitry has been limited to in vitro preparations from embryonic and neonatal mice. We describe two in vitro longitudinal lumbar spinal cord preparations from juvenile mice that allow the study of motoneuron properties and respective afferent or efferent spinal circuits through whole cell patch clamp. These preparations will be useful to those interested in the study of microcircuits at mature stages of motor development.
Topics: Animals; Electrophysiological Phenomena; Lumbosacral Region; Mammals; Mice; Motor Neurons; Patch-Clamp Techniques; Spinal Cord; Spinal Cord Dorsal Horn
PubMed: 35946796
DOI: 10.1152/jn.00184.2022 -
Acta Neurologica Belgica Apr 2022This study aimed to compare the annualized segmental cervical spinal cord atrophy rate (ASCAR) in the early and late stages of relapsing remitting multiple sclerosis...
This study aimed to compare the annualized segmental cervical spinal cord atrophy rate (ASCAR) in the early and late stages of relapsing remitting multiple sclerosis (RRMS), and to investigate the relationship between ASCAR and no evidence of disease activity (NEDA) in RRMS. Participants in this study included early stage MS (EMSg) patients, late stage MS (LMSg) patients, and healthy controls. All of the included participants (n = 175 subjects) were followed up for 14 months, and an MRI was performed on each participant at the beginning and at the end of the study. Cervical spinal cord average segmental area (CSCA) was measured by a semi-automated method, and ASCAR (mm/year) was calculated. Data from the EMSg (n = 81 subjects) and LMSg (n = 94 subjects) patient groups were compared with each other and with the control group (n = 43 subjects). Examination of the initial CSCA values revealed that the baseline CSCA of the control group was larger than that of the EMSg (p < 0.001), and the baseline CSCA of the EMSg was larger than that of the LMSg (p < 0.001). The ASCAR of the control group, LMSg, and EMSg were 0.48, 0.93, and 1.81 mm (p < 0.001), respectively. Regression analysis revealed that disability increase was associated with ASCAR, while MRI activity and relapse presence were unrelated to ASCAR. In both patient groups, ASCAR was slower in those who fulfilled NEDA but this relationship was not significant. Cervical spinal cord atrophy progression over time occurs at a greater rate in the early stages of RRMS disease compared to the late stages. ASCAR was unrelated to MRI activity and relapse, which are clinical markers of acute inflammation.
Topics: Atrophy; Cervical Cord; Disease Progression; Humans; Magnetic Resonance Imaging; Multiple Sclerosis; Multiple Sclerosis, Relapsing-Remitting; Recurrence; Spinal Cord
PubMed: 33475987
DOI: 10.1007/s13760-021-01595-4 -
No Shinkei Geka. Neurological Surgery May 2023Since the beginning of the 21st century, as intraoperative monitoring has been steadily spreading in Japan and globally, the values of motor-evoked potentials,...
Since the beginning of the 21st century, as intraoperative monitoring has been steadily spreading in Japan and globally, the values of motor-evoked potentials, visual-evoked potentials, and cortical-evoked potentials have been described. There are a wide variety of monitoring methods; the diseases handled are not limited to brain lesions, but extend also to spinal cord and spinal lesions; and there are many problems that have not yet been solved. Possible precautions are indicated by means of a video of an actual case site. Considerations are presented regarding the setting of this monitoring method, utilized in relatively frequent diseases and associated intraoperative judgments.
Topics: Humans; Evoked Potentials, Somatosensory; Evoked Potentials, Motor; Spinal Cord; Monitoring, Intraoperative; Japan
PubMed: 37211727
DOI: 10.11477/mf.1436204762 -
The Journal of Veterinary Medical... Sep 2022A 12-year and 3-month spayed female mixed cat was presented with severe lumbar pain. Magnetic resonance imaging and postmortem examination revealed a swollen lesion in...
A 12-year and 3-month spayed female mixed cat was presented with severe lumbar pain. Magnetic resonance imaging and postmortem examination revealed a swollen lesion in the spinal cord at L3 level. Histologic examination identified extensive neoplastic cell proliferation with massive necrosis in the tumor tissue. Two types of neoplastic cells were recognized. One type of neoplastic cells were large cells characterized by round to polygonal shape and abundant eosinophilic cytoplasm (referred to as "large cells"). The other neoplastic cells were small, densely proliferated, and had round to irregular shape and scant eosinophilic cytoplasm (referred to as "small cells"). Both types of cells were positive for oligodendrocyte transcription factor 2 and SRY-box transcription factor 10. Glial fibrillary acidic protein was positive in large cells but negative in most small cells. Digital analysis for Ki-67-stained tumor tissues found that total 21.1% ± 6.5% of tumor cells were positive for Ki-67. Based on these findings, we diagnosed malignant oligoastrocytoma in the spinal cord.
Topics: Animals; Female; Ki-67 Antigen; Magnetic Resonance Imaging; Oligodendroglioma; Spinal Cord; Spinal Cord Neoplasms
PubMed: 35908858
DOI: 10.1292/jvms.22-0144 -
Journal of Neurophysiology Dec 2020The gray matter of the spinal cord is the seat of somata of various types of neurons devoted to the sensory and motor activities of the limbs and trunk as well as a part...
The gray matter of the spinal cord is the seat of somata of various types of neurons devoted to the sensory and motor activities of the limbs and trunk as well as a part of the autonomic nervous system. The volume of the spinal gray matter is an indicator of the local neuronal processing, and this can decrease due to atrophy associated with degenerative diseases and injury. Nevertheless, the absolute volume of the human spinal cord has rarely been reported, if ever. Here, we use high-resolution magnetic resonance imaging, with a cross-sectional resolution of 50 × 50 μm and a voxel size of 0.0005 mm to estimate the total gray and white matter volume of a post mortem human female spinal cord. Segregation of gray and white matter was accomplished using deep learning image segmentation. Furthermore, we include data from a male spinal cord of a previously published study. The gray and white matter volumes were found to be 2.87 and 11.33 mL, respectively, for the female and 3.55 and 19.33 mL, respectively, for the male. The gray and white matter profiles along the vertebral axis were found to be strikingly similar, and the volumes of the cervical, thoracic, and lumbosacral sections were almost equal. Here, we combine high-field MRI (9.4 T) and deep learning for a post mortem reconstruction of the gray and white matter in human spinal cords. We report a minuscule total gray matter volume of 2.87 mL for a female and 3.55 mL for a male. For comparison, these volumes correspond approximately to the distal digit of the little finger.
Topics: Aged, 80 and over; Deep Learning; Female; Gray Matter; Humans; Magnetic Resonance Imaging; Male; Neuroimaging; Spinal Cord; White Matter
PubMed: 33085549
DOI: 10.1152/jn.00413.2020