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NeuroImage Dec 2021Most of our knowledge about the human spinal ascending (sensory) and descending (motor) pathways comes from non-invasive electrophysiological investigations. However,... (Review)
Review
Most of our knowledge about the human spinal ascending (sensory) and descending (motor) pathways comes from non-invasive electrophysiological investigations. However, recent methodological advances in acquisition and analyses of functional magnetic resonance imaging (fMRI) data from the spinal cord, either alone or in combination with the brain, have allowed us to gain further insights into the organization of this structure. In the current review, we conducted a systematic search to produced somatotopic maps of the spinal fMRI activity observed through different somatosensory, motor and resting-state paradigms. By cross-referencing these human neuroimaging findings with knowledge acquired through neurophysiological recordings, our review demonstrates that spinal fMRI is a powerful tool for exploring, in vivo, the human spinal cord pathways. We report strong cross-validation between task-related and resting-state fMRI in accordance with well-known hemicord, postero-anterior and rostro-caudal organization of these pathways. We also highlight the specific advantages of using spinal fMRI in clinical settings to characterize better spinal-related impairments, predict disease progression, and guide the implementation of therapeutic interventions.
Topics: Humans; Magnetic Resonance Imaging; Spinal Cord
PubMed: 34732324
DOI: 10.1016/j.neuroimage.2021.118684 -
Sensors (Basel, Switzerland) Oct 2022The ability to execute limb motions derives from composite command signals (or efferent signals) that stem from the central nervous system through the highway of the...
The ability to execute limb motions derives from composite command signals (or efferent signals) that stem from the central nervous system through the highway of the spinal cord and peripheral nerves to the muscles that drive the joints [...].
Topics: Electromyography; Spinal Cord; Muscles; Peripheral Nerves
PubMed: 36298317
DOI: 10.3390/s22207966 -
Magnetic Resonance in Medicine Feb 2021To present the results of the first human spinal cord in vivo MRI scans at 9.4T.
PURPOSE
To present the results of the first human spinal cord in vivo MRI scans at 9.4T.
METHODS
A human brain coil was used to image the human spinal cord at 9.4T. All anatomical images were acquired with a T *-weighted gradient-echo sequence. A comparison of the influence of four different B shimming routines on the image quality was performed. Intrinsic signal-to-noise-ratio maps were determined using a pseudo-multiple replica approach. Measurements with different echo times were compared and processed to one multiecho data image combination image. Based on the multiecho acquisitions, T *-relaxation time maps were calculated. Algorithmic spinal cord detection and gray matter/white matter segmentation were tested.
RESULTS
An echo time between 9 and 13.8 ms compromised best between gray matter/white matter contrast and image quality. A maximum in-plane resolution of 0.15 × 0.15 mm was achieved for anatomical images. These images offered excellent image quality and made small structures of the spinal cord visible. The scanner vendor implemented B shimming routine performed best during this work. Intrinsic signal-to-noise-ratio values of between 6600 and 8060 at the upper cervical spinal cord were achieved. Detection and segmentation worked reliably. An average T *-time of 24.88 ms ± 6.68 ms for gray matter and 19.37 ms ± 8.66 ms for white matter was calculated.
CONCLUSION
The proposed human brain coil can be used to image the spinal cord. The maximum in-plane resolution in this work was higher compared with the 7T results from the literature. The 9.4T acquisitions made the small structures of the spinal cord clearly visible.
Topics: Brain; Gray Matter; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Spinal Cord; White Matter
PubMed: 32789980
DOI: 10.1002/mrm.28455 -
No Shinkei Geka. Neurological Surgery Nov 2021The spinal cord comprises a crucial neural network, which is connected to the brain. Due to the fragility of the spinal cord, it is surrounded by the spine for...
The spinal cord comprises a crucial neural network, which is connected to the brain. Due to the fragility of the spinal cord, it is surrounded by the spine for protection. It is vital in clinical diagnosis to understand the role of the spinal tracts(lateral corticospinal tract, lateral spinothalamic tract, and posterior column)and the local circuit(anterior and posterior horns).
Topics: Animals; Humans; Pyramidal Tracts; Spinal Cord
PubMed: 34879335
DOI: 10.11477/mf.1436204502 -
Ultrasound in Obstetrics & Gynecology :... Aug 2023Diffusion tensor imaging (DTI) of the fetal brain is a relatively new technique that allows evaluation of white matter tracts of the central nervous system throughout...
OBJECTIVES
Diffusion tensor imaging (DTI) of the fetal brain is a relatively new technique that allows evaluation of white matter tracts of the central nervous system throughout pregnancy, as well as in certain pathological conditions. The objectives of this study were to evaluate the feasibility of DTI of the spinal cord in utero and to examine gestational-age (GA)-related changes in DTI parameters during pregnancy.
METHODS
This was a prospective study conducted between December 2021 and June 2022 in the LUMIERE Platform, Necker-Enfants Malades Hospital, Paris, France, as part of the LUMIERE SUR LE FETUS trial. Women with a pregnancy between 18 and 36 weeks of gestation without fetal or maternal abnormality were eligible for inclusion. Sagittal diffusion-weighted scans of the fetal spine were acquired, without sedation, using a 1.5-Tesla magnetic resonance imaging scanner. The imaging parameters were as follows: 15 non-collinear direction diffusion-weighted magnetic-pulsed gradients with a b-value 700 s/mm and one B0 image without diffusion-weighting; slice thickness, 3 mm; field of view (FOV), 36 mm; phase FOV, 1.00; voxel size, 4.5 × 2.8 × 3 mm ; number of slices, 7-10; repetition time, 2800 ms; echo time, minimum; and total acquisition time, 2.3 min. DTI parameters, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC), were extracted at the cervical, upper thoracic, lower thoracic and lumbar levels of the spinal cord. Cases with motion degradation and those with aberrant reconstruction of the spinal cord on tractography were excluded. Pearson's correlation analysis was performed to evaluate GA-related changes of DTI parameters during pregnancy.
RESULTS
During the study period, 42 pregnant women were included at a median GA of 29.3 (range, 22.0-35.7) weeks. Five (11.9%) patients were not included in the analysis because of fetal movement. Two (4.8%) patients with aberrant tractography reconstruction were also excluded from analysis. Acquisition of DTI parameters was feasible in all remaining cases (35/35). Increasing GA correlated with increasing FA averaged over the entire fetal spinal cord (r, 0.37; P < 0.01), as well as at the individual cervical (r, 0.519; P < 0.01), upper thoracic (r, 0.468; P < 0.01), lower thoracic (r, 0.425; P = 0.02) and lumbar (r, 0.427; P = 0.02) levels. There was no correlation between GA and ADC averaged over the entire spinal cord (r, 0.01; P = 0.99) or at the individual cervical (r, -0.109; P = 0.56), upper thoracic (r, -0.226; P = 0.22), lower thoracic (r, -0.052; P = 0.78) or lumbar (r, -0.11; P = 0.95) levels.
CONCLUSIONS
This study shows that DTI of the spinal cord is feasible in normal fetuses in typical clinical practice and allows extraction of DTI parameters of the spinal cord. There is a significant GA-related change in FA in the fetal spinal cord during pregnancy, which may result from decreasing water content as observed during myelination of fiber tracts occurring in utero. This study may serve as a basis for further investigation of DTI in the fetus, including research into its potential in pathological conditions that impact spinal cord development. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.
Topics: Humans; Female; Pregnancy; Diffusion Tensor Imaging; Prospective Studies; Feasibility Studies; Spinal Cord; White Matter
PubMed: 36971038
DOI: 10.1002/uog.26208 -
Sheng Li Xue Bao : [Acta Physiologica... Jun 2021Spinal cord magnetic resonance imaging (MRI) is an advanced imaging technique (mainly in the cervical cord) and has been gradually used in basic scientific research such... (Review)
Review
Spinal cord magnetic resonance imaging (MRI) is an advanced imaging technique (mainly in the cervical cord) and has been gradually used in basic scientific research such as human sensation and motor function, and clinical applications such as spinal cord injury, myelitis, and chronic pain, etc. The development of spinal cord MRI is still at the early stage compared with brain MRI and limited by the current MRI technology and data analysis methods. This review focuses on the methods and applications of spinal cord MRI technology in the basic research fields of cognitive neuroscience and clinical application. Firstly, we will introduce the imaging principle, methods, measurement standards, and applications of most commonly used multimodal spinal cord MRI techniques, including quantitative spinal cord MRI (such as structural, diffusion, spectroscopy, myelin water, magnetization transfer, and chemical exchange saturation transfer imaging, etc.) and spinal functional MRI (fMRI). Secondly, we will discuss the technical challenges and possible solutions of spinal cord MRI data processing from the three dimensions of denoising, data processing pipeline optimization, and repeatability and reliability. Finally, we will discuss the application status and development prospects of spinal cord MRI.
Topics: Humans; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Reproducibility of Results; Spinal Cord; Spinal Cord Injuries
PubMed: 34230941
DOI: No ID Found -
Cell Death & Disease Nov 2019The vascular system of the spinal cord is particularly complex and vulnerable. Damage to the main vessels or alterations to the regulation of blood flow will result in a... (Review)
Review
The vascular system of the spinal cord is particularly complex and vulnerable. Damage to the main vessels or alterations to the regulation of blood flow will result in a reduction or temporary cessation of blood supply. The resulting tissue hypoxia may be brief: acute, or long lasting: chronic. Damage to the vascular system of the spinal cord will develop after a traumatic event or as a result of pathology. Traumatic events such as road traffic accidents, serious falls and surgical procedures, including aortic cross-clamping, will lead to an immediate cessation of perfusion, the result of which may not be evident for several days, but may have long-term consequences including neurodegeneration. Pathological events such as arterial sclerosis, venous occlusion and spinal cord compression will result in a progressive reduction of blood flow, leading to chronic hypoxia. While in some situations the initial pathology is exclusively vascular, recent research in neurodegenerative disease has drawn attention to concomitant vascular anomalies in disorders, including amyotrophic lateral sclerosis, spinal muscular atrophy and muscular sclerosis. Understanding the role of, and tissue response to, chronic hypoxia is particularly important in these cases, where inherent neural damage exacerbates the vulnerability of the nervous system to stressors including hypoxia.
Topics: Humans; Hypoxia; Neurodegenerative Diseases; Regional Blood Flow; Spinal Cord; Spinal Cord Injuries
PubMed: 31723121
DOI: 10.1038/s41419-019-2104-1 -
Glia Jul 2021Astrocytes are indispensable for proper neuronal functioning. Given the diverse needs of neuronal circuits and the variety of tasks astrocytes perform, the perceived...
Astrocytes are indispensable for proper neuronal functioning. Given the diverse needs of neuronal circuits and the variety of tasks astrocytes perform, the perceived homogeneous nature of astrocytes has been questioned. In the spinal dorsal horn, complex neuronal circuitries regulate the integration of sensory information of different modalities. The dorsal horn is organized in a distinct laminar manner based on termination patterns of high- and low-threshold afferent fibers and neuronal properties. Neurons in laminae I (L1) and II (L2) integrate potentially painful, nociceptive information, whereas neurons in lamina III (L3) and deeper laminae integrate innocuous, tactile information from the periphery. Sensory information is also integrated by an uncharacterized network of astrocytes. How these lamina-specific characteristics of neuronal circuits of the dorsal horn are of functional importance for properties of astrocytes is currently unknown. We addressed if astrocytes in L1, L2, and L3 of the upper dorsal horn of mice are differentially equipped for the needs of neuronal circuits that process sensory information of different modalities. We found that astrocytes in L1 and L2 were characterized by a higher density, higher expression of GFAP, Cx43, and GLAST and a faster coupling speed than astrocytes located in L3. L1 astrocytes were more responsive to Kir4.1 blockade and had higher levels of AQP4 compared to L3 astrocytes. In contrast, basic membrane properties, network formation, and somatic intracellular calcium signaling were similar in L1-L3 astrocytes. Our data indicate that the properties of spinal astrocytes are fine-tuned for the integration of nociceptive versus tactile information.
Topics: Animals; Astrocytes; Mice; Neurons; Posterior Horn Cells; Spinal Cord; Spinal Cord Dorsal Horn
PubMed: 33694249
DOI: 10.1002/glia.23990 -
Magnetic Resonance Imaging Oct 2023Multi-parametric MRI (mpMRI) technology enables non-invasive and quantitative assessments of the structural, molecular, and functional characteristics of various... (Review)
Review
Multi-parametric MRI (mpMRI) technology enables non-invasive and quantitative assessments of the structural, molecular, and functional characteristics of various neurological diseases. Despite the recognized importance of studying spinal cord pathology, mpMRI applications in spinal cord research have been somewhat limited, partly due to technical challenges associated with spine imaging. However, advances in imaging techniques and improved image quality now allow longitudinal investigations of a comprehensive range of spinal cord pathological features by exploiting different endogenous MRI contrasts. This review summarizes the use of mpMRI techniques including blood oxygenation level-dependent (BOLD) functional MRI (fMRI), diffusion tensor imaging (DTI), quantitative magnetization transfer (qMT), and chemical exchange saturation transfer (CEST) MRI in monitoring different aspects of spinal cord pathology. These aspects include cyst formation and axonal disruption, demyelination and remyelination, changes in the excitability of spinal grey matter and the integrity of intrinsic functional circuits, and non-specific molecular changes associated with secondary injury and neuroinflammation. These approaches are illustrated with reference to a nonhuman primate (NHP) model of traumatic cervical spinal cord injuries (SCI). We highlight the benefits of using NHP SCI models to guide future studies of human spinal cord pathology, and demonstrate how mpMRI can capture distinctive features of spinal cord pathology that were previously inaccessible. Furthermore, the development of mechanism-based MRI biomarkers from mpMRI studies can provide clinically useful imaging indices for understanding the mechanisms by which injured spinal cords progress and repair. These biomarkers can assist in the diagnosis, prognosis, and evaluation of therapies for SCI patients, potentially leading to improved outcomes.
Topics: Animals; Humans; Diffusion Tensor Imaging; Multiparametric Magnetic Resonance Imaging; Spinal Cord Injuries; Magnetic Resonance Imaging; Spinal Cord; Models, Animal
PubMed: 37343904
DOI: 10.1016/j.mri.2023.06.007 -
NeuroImage Oct 2021Spontaneous fluctuations of Blood Oxygenation-Level Dependent (BOLD) MRI signal in a resting state have previously been detected and analyzed to describe intrinsic...
Spontaneous fluctuations of Blood Oxygenation-Level Dependent (BOLD) MRI signal in a resting state have previously been detected and analyzed to describe intrinsic functional networks in the spinal cord of rodents, non-human primates and human subjects. In this study we combined high resolution imaging at high field with data-driven Independent Component Analysis (ICA) to i) delineate fine-scale functional networks within and between segments of the cervical spinal cord of monkeys, and also to ii) characterize the longitudinal effects of a unilateral dorsal column injury on these networks. Seven distinct functional hubs were revealed within each spinal segment, with new hubs detected at bilateral intermediate and gray commissure regions in addition to the bilateral dorsal and ventral horns previously reported. Pair-wise correlations revealed significantly stronger connections between hubs on the dominant hand side. Unilateral dorsal-column injuries disrupted predominantly inter-segmental rather than intra-segmental functional connectivities as revealed by correlation strengths and graph-theory based community structures. The effects of injury on inter-segmental connectivity were evident along the length of the cord both below and above the lesion region. Connectivity strengths recovered over time and there was revival of inter-segmental communities as animals recovered function. BOLD signals of frequency 0.01-0.033 Hz were found to be most affected by injury. The results in this study provide new insights into the intrinsic functional architecture of spinal cord and underscore the potential of functional connectivity measures to characterize changes in networks after an injury and during recovery.
Topics: Animals; Connectome; Spinal Cord; Spinal Cord Injuries
PubMed: 34271158
DOI: 10.1016/j.neuroimage.2021.118391