Contribution of changes in the spinal cord and brain to the onset and progression of hand clumsiness symptoms in cervical spondylotic myelopathy.

OBJECTIVE: Cervical spondylotic myelopathy (CSM) stands as the most prevalent form of spinal cord injury, frequently prompting various changes in both the brain and spinal cord. However, the precise nature of these changes within the brains and spinal cords of CSM patients experiencing hand clumsiness (HCL) symptoms has remained elusive. The authors aimed to scrutinize these alterations and explore potential links between these changes and the onset of HCL symptoms. METHODS: Using the modified Japanese Orthopaedic Association (mJOA) scale, the authors classified CSM patients into two groups: those without HCL and those with HCL. The authors performed voxel-wise z-score transformation amplitude of low-frequency fluctuations (zALFF) and resting-state functional connectivity (FC) evaluations in the brain. Additionally, they used the Spinal Cord Toolbox to calculate the fractional anisotropy (FA) of spinal cord tracts. The analysis also encompassed an examination of the correlation of these measures with improvements in mJOA scores. RESULTS: Significant disparities in zALFF values surfaced in the right calcarine, right cuneus, right precuneus, right middle occipital gyrus (MOG), right superior occipital gyrus (SOG), and right superior parietal gyrus (SPG) between healthy controls (HC), patients without HCL, and patients with HCL, primarily within the visual cortex. In the patient group, patients with HCL displayed reduced FC between the right calcarine, right MOG, right SOG, right SPG, right SFG, bilateral MFG, and left median cingulate and paracingulate gyri when compared with patients without HCL. Moreover, significant differences in FA values of the corticospinal tract (CST) and reticulospinal tract (REST) at the C2 level emerged among HC, patients without HCL, and patients with HCL. Notably, zALFF, FC, and FA values in specific brain regions and spinal cord tracts exhibited correlations with mJOA upper-extremity scores. Additionally, FA values of the CST and REST correlated with zALFF values in the right calcarine, right MOG, right SOG, and right SPG. CONCLUSIONS: Alterations within brain regions associated with the visual cortex, the fronto-parietal-occipital attention network, and spinal cord pathways appear to play a substantial role in the emergence and progression of HCL symptoms. Furthermore, the existence of a potential connection between the spinal cord and the brain suggests that this link might be related to the clinical symptoms of CSM.

A rare case of ispilateral hemiparesis in a patient with uncrossed pyramidal tract shown by tractography.

This article presents a unique case of ipsilateral hemiparesis in a 66-year-old individual, contrary to the conventional understanding of supratentorial strokes causing contralateral neurological deficits. The patient exhibited persistent weakness and sensory abnormalities on the left side of the body following a left occipital infarct. Neuroimaging revealed a chronic stroke in the left occipital lobe, with diffusion tensor imaging demonstrating uncrossed pyramidal tracts at the level of the medulla. The discussion encompasses the anatomical basis of corticospinal tract crossing, historical perspectives, and previous documented cases of ipsilateral strokes. The rarity of complete uncrossed corticospinal tracts without underlying congenital abnormalities or genetic disorders is highlighted. The study underscores the importance of considering such atypical presentations in stroke evaluations and the role of advanced imaging techniques in confirming diagnosis and understanding underlying mechanisms.

Evidence for reticulospinal plasticity underlying motor recovery in Brown-Séquard-plus Syndrome: a case report.

Brown-Séquard Syndrome (BSS) is a rare neurological condition caused by a unilateral spinal cord injury (SCI). Upon initial ipsilesional hemiplegia, patients with BSS typically show substantial functional recovery over time. Preclinical studies on experimental BSS demonstrated that spontaneous neuroplasticity in descending motor systems is a key mechanism promoting functional recovery. The reticulospinal (RS) system is one of the main descending motor systems showing a remarkably high ability for neuroplastic adaptations after incomplete SCI. In humans, little is known about the contribution of RS plasticity to functional restoration after SCI. Here, we investigated RS motor drive to different muscles in a subject with Brown-Séquard-plus Syndrome (BSPS) five months post-injury using the StartReact paradigm. RS drive was compared between ipsi- and contralesional muscles, and associated with measures of functional recovery. Additionally, corticospinal (CS) drive was investigated using transcranial magnetic stimulation (TMS) in a subset of muscles. The biceps brachii showed a substantial enhancement of RS drive on the ipsi- vs. contralesional side, whereas no signs of CS plasticity were found ipsilesionally. This finding implies that motor recovery of ipsilesional elbow flexion is primarily driven by the RS system. Results were inversed for the ipsilesional tibialis anterior, where RS drive was not augmented, but motor-evoked potentials recovered over six months post-injury, suggesting that CS plasticity contributed to improvements in ankle dorsiflexion. Our findings indicate that the role of RS and CS plasticity in motor recovery differs between muscles, with CS plasticity being essential for the restoration of distal extremity motor function, and RS plasticity being important for the functional recovery of proximal flexor muscles after SCI in humans.

Ultra-early navigated transcranial magnetic stimulation for perioperative stroke: anatomo-functional report.

Navigated repetitive transmagnetic stimulation is a non-invasive and safe brain activity modulation technique. When combined with the classical rehabilitation process in stroke patients it has the potential to enhance the overall neurologic recovery. We present a case of a peri-operative stroke, treated with ultra-early low frequency navigated repetitive transmagnetic stimulation over the contralesional hemisphere. The patient received low frequency navigated repetitive transmagnetic stimulation within 12 hours of stroke onset for seven consecutive days and a significant improvement in his right sided weakness was noticed and he was discharge with normal power. This was accompanied by an increase in the number of positive responses evoked by navigated repetitive transmagnetic stimulation and a decrease of the resting motor thresholds at a cortical level. Subcortically, a decrease in the radial, axial, and mean diffusivity were recorded in the ipsilateral corticospinal tract and an increase in fractional anisotropy, axial diffusivity, and mean diffusivity was observed in the interhemispheric fibers of the corpus callosum responsible for the interhemispheric connectivity between motor areas. Our case demonstrates clearly that ultra-early low frequency navigated repetitive transmagnetic stimulation applied to the contralateral motor cortex can lead to significant clinical motor improvement in patients with subcortical stroke.

Nurr1 overexpression in the primary motor cortex alleviates motor dysfunction induced by intracerebral hemorrhage in the striatum in mice.

Hemorrhage-induced injury of the corticospinal tract (CST) in the internal capsule (IC) causes severe neurological dysfunction in both human patients and rodent models of intracerebral hemorrhage (ICH). A nuclear receptor Nurr1 (NR4A2) is known to exert anti-inflammatory and neuroprotective effects in several neurological disorders. Previously we showed that Nurr1 ligands prevented CST injury and alleviated neurological deficits after ICH in mice. To prove direct effect of Nurr1 on CST integrity, we examined the effect of Nurr1 overexpression in neurons of the primary motor cortex on pathological consequences of ICH in mice. ICH was induced by intrastriatal injection of collagenase type VII, where hematoma invaded into IC. Neuron-specific overexpression of Nurr1 was induced by microinjection of synapsin I promoter-driven adeno-associated virus (AAV) vector into the primary motor cortex. Nurr1 overexpression significantly alleviated motor dysfunction but showed only modest effect on sensorimotor dysfunction after ICH. Nurr1 overexpression also preserved axonal structures in IC, while having no effect on hematoma-associated inflammatory events, oxidative stress, and neuronal death in the striatum after ICH. Immunostaining revealed that Nurr1 overexpression increased the expression of Ret tyrosine kinase and phosphorylation of Akt and ERK1/2 in neurons in the motor cortex. Moreover, administration of Nurr1 ligands 1,1-bis(3'-indolyl)-1-(p-chlorophenyl)methane or amodiaquine increased phosphorylation levels of Akt and ERK1/2 as well as expression of glial cell line-derived neurotrophic factor and Ret genes in the cerebral cortex. These results suggest that the therapeutic effect of Nurr1 on striatal ICH is attributable to the preservation of CST by acting on cortical neurons.

Structural changes in corticospinal tract profiling via multishell diffusion models and their relation to overall survival in glioblastoma.

PURPOSE: Advanced MR fiber tracking imaging reflects fiber bundle invasion by glioblastoma, particularly of the corticospinal tract (CST), which is more susceptible as the largest downstream fiber tracts. We aimed to investigate whether CST features can predict the overall survival of glioblastoma. METHODS: In this prospective secondary analysis, 40 participants (mean age, 58 years; 16 male) pathologically diagnosed with glioblastoma were enrolled. Diffusion spectrum MRI was used for CST reconstruction. Fifty morphological and diffusion indicators (DTI, DKI, NODDI, MAP and Q-space) were used to characterize the CST. Optimal parameters capturing fiber bundle damage were obtained through various grouping methods. Eventually, the correlation with overall survival was determined by the hazard ratios (HRs) from various Cox proportional hazard model combinations. RESULTS: Only intracellular volume fraction (ICVF) and non-Gaussianity (NG) values on the affected tumor level were significant in all four groups or stratified comparisons (all P < .05). During the median follow-up 698 days, only the ICVF on the affected tumor level was independently associated with overall survival, even after adjusting for all classic prognostic factors (HR [95 % CI]: 0.611 [0.403, 0.927], P = .021). Moreover, stratification by the ICVF on the affected tumor level successfully predicted risk (P < .01) and improved the C-index of the multivariate model (from 0.695 to 0.736). CONCLUSIONS: This study demonstrates a relationship between NODDI-derived CST features, ICVF on the affected tumor level, and overall survival in glioblastoma. Independent of classical prognostic factors for glioblastoma, a lower ICVF on the affected tumor level might predict a lower overall survival.

Selenoprotein I is indispensable for ether lipid homeostasis and proper myelination.

Selenoprotein I (SELENOI) catalyzes the final reaction of the CDP-ethanolamine branch of the Kennedy pathway, generating the phospholipids phosphatidylethanolamine (PE) and plasmenyl-PE. Plasmenyl-PE is a key component of myelin and is characterized by a vinyl ether bond that preferentially reacts with oxidants, thus serves as a sacrificial antioxidant. In humans, multiple loss-of-function mutations in genes affecting plasmenyl-PE metabolism have been implicated in hereditary spastic paraplegia, including SELENOI. Herein, we developed a mouse model of nervous system-restricted SELENOI deficiency that circumvents embryonic lethality caused by constitutive deletion and recapitulates phenotypic features of hereditary spastic paraplegia. Resulting mice exhibited pronounced alterations in brain lipid composition, which coincided with motor deficits and neuropathology including hypomyelination, elevated reactive gliosis, and microcephaly. Further studies revealed increased lipid peroxidation in oligodendrocyte lineage cells and disrupted oligodendrocyte maturation both in vivo and in vitro. Altogether, these findings detail a critical role for SELENOI-derived plasmenyl-PE in myelination that is of paramount importance for neurodevelopment.

Hypothermia protects the integrity of corticospinal tracts and alleviates mitochondria injury after intracerebral hemorrhage in mice.

Disruption of corticospinal tracts (CST) is a leading factor for motor impairments following intracerebral hemorrhage (ICH) in the striatum. Previous studies have shown that therapeutic hypothermia (HT) improves outcomes of ICH patients. However, whether HT has a direct protection effect on the CST integrity and the underlying mechanisms remain largely unknown. In this study, we employed a chemogenetics approach to selectively activate bilateral warm-sensitive neurons in the preoptic areas to induce a hypothermia-like state. We then assessed effects of HT treatment on the integrity of CST and motor functional recovery after ICH. Our results showed that HT treatment significantly alleviated axonal degeneration around the hematoma and the CST axons at remote midbrain region, ultimately promoted skilled motor function recovery. Anterograde and retrograde tracing revealed that HT treatment protected the integrity of the CST over an extended period. Mechanistically, HT treatment prevented mitochondrial swelling in degenerated axons around the hematoma, alleviated mitochondrial impairment by reducing mitochondrial ROS accumulation and improving mitochondrial membrane potential in primarily cultured cortical neurons with oxyhemoglobin treatment. Serving as a proof of principle, our study provided novel insights into the application of HT to improve functional recovery after ICH.

Exploring the Structural Plasticity Mechanism of Corticospinal Tract during Stroke Rehabilitation Based Automated Fiber Quantification Tractography.

BACKGROUND: Corticospinal tract (CST) is the principal motor pathway; we aim to explore the structural plasticity mechanism in CST during stroke rehabilitation. METHODS: A total of 25 patients underwent diffusion tensor imaging before rehabilitation (T1), 1-month post-rehabilitation (T2), 2 months post-rehabilitation (T3), and 1-year post-discharge (T4). The CST was segmented, and fractional anisotropy (FA), axial diffusion (AD), mean diffusivity (MD), and radial diffusivity (RD) were determined using automated fiber quantification tractography. Baseline level of laterality index (LI) and motor function for correlation analysis. RESULTS: The FA values of all segments in the ipsilesional CST (IL-CST) were lower compared with normal CST. Repeated measures analysis of variance showed time-related effects on FA, AD, and MD of the IL-CST, and there were similar dynamic trends in these 3 parameters. At T1, FA, AD, and MD values of the mid-upper segments of IL-CST (around the core lesions) were the lowest; at T2 and T3, values for the mid-lower segments were lower than those at T1, while the values for the mid-upper segments gradually increased; at T4, the values for almost entire IL-CST were higher than before. The highest LI was observed at T2, with a predominance in contralesional CST. The LIs for the FA and AD at T1 were positively correlated with the change rate of motor function. CONCLUSIONS: IL-CST showed aggravation followed by improvement from around the lesion to the distal end. Balance of interhemispheric CST may be closely related to motor function, and LIs for FA and AD may have predictive value for mild-to-moderate stroke rehabilitation. Clinical Trial Registration. URL: http://www.chictr.org.cn; Unique Identifier: ChiCTR1800019474.

Maximal Resection of Gliomas Adjacent to the Corticospinal Tract Using 3-T Intraoperative Magnetic Resonance Imaging.

BACKGROUND: Gliomas adjacent to the corticospinal tract (CST) should be carefully resected to preserve motor function while achieving maximal surgical resection. Modern high-field intraoperative magnetic resonance imaging (iMRI) enables precise visualization of the residual tumor and intraoperative tractography. We prospectively evaluated the extent of resection and distance between the tumor resection cavity and CST using 3-T iMRI combined with motor evoked potentials (MEP) in glioma surgery. METHODS: Participants comprised patients who underwent surgery for solitary supratentorial glioma located within 10 mm of the CST. All cases underwent surgery using neuronavigation with overlaid CST under MEP monitoring. The correlation between distance from CST and transcortical MEP amplitude was calculated using Spearman rank correlation. RESULTS: Among the 63 patients who underwent surgery, 27 patients were enrolled in the study. Gross total resections were achieved in 26 of the 27 cases. Volumetric analysis showed the extent of resection was 98.6%. Motor function was stable or improved in 24 patients (Stable/Improved group) and deteriorated in 3 patients (Deteriorated group). All patients in the Deteriorated group showed motor deficit before surgery. Mean intraoperative minimal distance was significantly longer in the Stable/Improved group (7.3 mm) than in the Deteriorated group (1.1 mm; P < 0.05). MEP amplitude correlated with minimal distance between the resection cavity and CST (R = 0.64). CONCLUSIONS: Resection of gliomas adjacent to CST with a navigation system using 3-T iMRI could result in an ultimate EOR >98%. The combination of intraoperative tractography and MEP contributes to maximal removal of motor-eloquent gliomas.

Repetitive Transcranial Magnetic Stimulation Combined with Sling Exercise Modulates the Motor Cortex in Patients with Chronic Low Back Pain.

The study aims to explore the effects of combining repetitive transcranial magnetic stimulation (rTMS) with sling exercise (SE) intervention in patients with chronic low back pain (CLBP). This approach aims to directly stimulate brain circuits and indirectly activate trunk muscles to influence motor cortex plasticity. However, the impact of this combined intervention on motor cortex organization and clinical symptom improvement is still unclear, as well as whether it is more effective than either intervention alone. To investigate this, patients with CLBP were randomly assigned to three groups: SE/rTMS, rTMS alone, and SE alone. Motor cortical organization, numerical pain rating scale (NPRS), Oswestry Disability Index (ODI), and postural balance stability were measured before and after a 2-week intervention. The results showed statistically significant differences in the representative location of multifidus on the left hemispheres, as well as in NPRS and ODI scores, in the combined SE/rTMS group after the intervention. When compared to the other two groups, the combined SE/rTMS group demonstrated significantly different motor cortical organization, sway area, and path range from the rTMS alone group, but not from the SE alone group. These findings highlight the potential benefits of a combined SE/rTMS intervention in terms of clinical outcomes and neuroadaptive changes compared to rTMS alone. However, there was no significant difference between the combined intervention and SE alone. Therefore, our research does not support the use of rTMS as a standalone treatment for CLBP. Our study contributed to optimizing treatment strategies for individuals suffering from CLBP.

A comparative study of diffusion kurtosis imaging and diffusion tensor imaging in detecting corticospinal tract impairment in diffuse glioma patients.

PURPOSE: This study aimed to investigate the diagnostic performance of diffusion kurtosis imaging (DKI) and diffusion tensor imaging (DTI) in identifying aberrations in the corticospinal tract (CST), whilst elucidating the relationship between abnormalities of CST and patients' motor function. METHODS: Altogether 21 patients with WHO grade II or grade IV glioma were enrolled and divided into Group 1 and Group 2, according to the presence or absence of preoperative paralysis. DKI and DTI metrics were generated and projected onto the CST. Histograms of the CST along x, y, and z axes were developed based on DKI and DTI metrics, and compared subsequently to determine regions of aberrations on the fibers. The receiver operating characteristic curve was performed to investigate the diagnostic efficacy of DKI and DTI metrics. RESULTS: In Group 1, a significantly lower fractional anisotropy, radial kurtosis and mean kurtosis, and a higher mean diffusivity were found in the ipsilateral CST as compared to the contralateral CST. Significantly higher relative axial diffusivity, relative radial diffusivity, and relative mean diffusivity (rMD) were found in Group 1, as compared to Group 2. The relative volume of ipsilateral CST abnormalities higher than the maximum value of mean kurtosis combined with rMD exhibited the best diagnostic performance in distinguishing dysfunction of CST with an AUC of 0.93. CONCLUSION: DKI is sensitive in detecting subtle changes of CST distal from the tumor. The combination of DKI and DTI is feasible for evaluating the impairment of the CST.

Determining intracortical, corticospinal and alpha motoneurone excitability in athletes with patellar tendinopathy compared to asymptomatic controls.

BACKGROUND: Lower capacity to generate knee extension maximal voluntary force (MVF) has been observed in individuals affected with patellar tendinopathy (PT) compared to asymptomatic controls. This MVF deficit is hypothesized to emanate from alterations in corticospinal excitability (CSE). The modulation of CSE is intricately linked to the excitability levels at multiple sites, encompassing neurones within the corticospinal tract (CST), intracortical neurones within the primary motor cortex (M1), and the alpha motoneurone. The aim of this investigation was to examine the excitability of intracortical neurones, CST neurones, and the alpha motoneurone, and compare these between volleyball and basketball athletes with PT and matched asymptomatic controls. METHOD: Nineteen athletes with PT and 18 asymptomatic controls participated in this cross-sectional study. Transcranial magnetic stimulation was utilized to assess CST excitability, corticospinal inhibition (silent period, and short-interval cortical inhibition). Peripheral nerve stimulation was used to evaluate lumbar spine and alpha motoneurone excitability, including the evocation of lumbar-evoked potentials and maximal compound muscle action potential (MMAX ), and CSE with central activation ratio (CAR). Knee extension MVF was also assessed. RESULTS: Athletes with PT exhibited longer silent period duration and greater electrical stimulator output for MMAX , as well as lower MVF, compared to asymptomatic controls (p < 0.05). CONCLUSION: These findings indicate volleyball and basketball athletes with PT exhibit reduced excitability of the alpha motoneurone or the neuromuscular junction, which may be linked to lower MVF. Subtle alterations at specific sites may represent compensatory changes to excitability aiming to maintain efferent drive to the knee extensors.

Effects of noninvasive neuromodulation targeting the spinal cord on early learning of force control by the digits.

AIMS: Control of finger forces underlies our capacity for skilled hand movements acquired during development and reacquired after neurological injury. Learning force control by the digits, therefore, predicates our functional independence. Noninvasive neuromodulation targeting synapses that link corticospinal neurons onto the final common pathway via spike-timing-dependent mechanisms can alter distal limb motor output on a transient basis, yet these effects appear subject to individual differences. Here, we investigated how this form of noninvasive neuromodulation interacts with task repetition to influence early learning of force control during precision grip. METHODS: The unique effects of neuromodulation, task repetition, and neuromodulation coinciding with task repetition were tested in three separate conditions using a within-subject, cross-over design (n = 23). RESULTS: We found that synchronizing depolarization events within milliseconds of stabilizing precision grip accelerated learning but only after accounting for individual differences through inclusion of subjects who showed upregulated corticospinal excitability at 2 of 3 time points following conditioning stimulation (n = 19). CONCLUSIONS: Our findings provide insights into how the state of the corticospinal system can be leveraged to drive early motor skill learning, further emphasizing individual differences in the response to noninvasive neuromodulation. We interpret these findings in the context of biological mechanisms underlying the observed effects and implications for emerging therapeutic applications.

Chronic Adaptations in the Dorsal Horn Following a Cervical Spinal Cord Injury in Primates.

Spinal cord injury (SCI) is devastating, with limited treatment options and variable outcomes. Most in vivo SCI research has focused on the acute and early post-injury periods, and the promotion of axonal growth, so little is understood about the clinically stable chronic state, axonal growth over time, and what plasticity endures. Here, we followed animals into the chronic phase following SCI, to address this gap. Male macaques received targeted deafferentation, affecting three digits of one hand, and were divided into short (4-6 months) or long-term (11-12 months) groups, based on post-injury survival times. Monkeys were assessed behaviorally, where possible, and all exhibited an initial post-injury deficit in manual dexterity, with gradual functional recovery over 2 months. We previously reported extensive sprouting of somatosensory corticospinal (S1 CST) fibers in the dorsal horn in the first five post-injury months. Here, we show that by 1 year, the S1 CST sprouting is pruned, with the terminal territory resembling control animals. This was reflected in the number of putatively "functional" synapses observed, which increased over the first 4-5 months, and then returned to baseline by 1 year. Microglia density also increased in the affected dorsal horn at 4-6 months and then decreased, but did not return to baseline by 1 year, suggesting refinement continues beyond this time. Overall, there is a long period of reorganization and consolidation of adaptive circuitry in the dorsal horn, extending well beyond the initial behavioral recovery. This provides a potential window to target therapeutic opportunities during the chronic phase.

Uptake of surface-functionalized thermo-responsive polymeric nanocarriers in corticospinal tract motor neurons.

Nanocarrier drug delivery systems are attractive options for targeted delivery of survival- and regeneration-enhancing therapeutics to neurons damaged by degenerative or traumatic central nervous system (CNS) lesions. Functional groups on nanocarrier surfaces allow derivatization with molecules to target specific cells but may affect cellular interactions and nanocarrier uptake. We synthesized differently sized -COOH and -NH2 surface functionalized polymeric nanocarriers (SFNCs) by emulsion copolymerization and assessed uptake by different cell types in mixed cortical cultures. Following 60-min incubation with SFNCs, mean intensity measurements of fluorescently labeled SFNCs indicated that corticospinal tract motor neurons (CSMNs) took up more COOH- or NH2- functionalized SFNCs with similar sizes (150 nm), compared to glia. However, larger diameter (750 nm) SFNCs were taken up at higher concentrations compared to smaller COOH-derivatized SFNCs (150 nm). These data suggest that larger SFNCs may provide an advantage for enhanced uptake by targeted neurons.

Assessing Postoperative Motor Risk in Insular Low-Grade Gliomas Patients: The Potential Role of Presurgery MRI Corticospinal Tract Shape Measures.

BACKGROUND: Insular low-grade gliomas (LGGs) are surgically challenging due to their proximity to critical structures like the corticospinal tract (CST). PURPOSE: This study aims to determine if preoperative CST shape metrics correlate with postoperative motor complications in insular LGG patients. STUDY TYPE: Retrospective. POPULATION: 42 patients (mean age 40.26 ± 10.21 years, 25 male) with insular LGGs. FIELD STRENGTH/SEQUENCE: Imaging was performed using 3.0 Tesla MRI, incorporating T1-weighted magnetization-prepared rapid gradient-echo, T2-weighted space dark-fluid with spin echo (SE), and diffusional kurtosis imaging (DKI) with gradient echo sequences, all integrated with echo planar imaging. ASSESSMENT: Shape metrics of the CST, including span, irregularity, radius, and irregularity of end regions (RER and IER, respectively), were compared between the affected and healthy hemispheres. Total end region radius (TRER) was determined as the sum of RER 1 and RER 2. The relationships between shape metrics and postoperative short-term (4 weeks) and long-term (>8 weeks) motor disturbances assessing by British Medical Research Council grading system, was analyzed using multivariable regression models. STATISTICAL TESTING: Paired t-tests compared CST metrics between hemispheres. Logistic regression identified associations between these metrics and motor disturbances. The models were developed using all available data and there was no independent validation dataset. Significance was set at P < 0.05. RESULTS: Short-term motor disturbance risk was significantly related to TRER (OR = 199.57). Long-term risk significantly correlated with IER 1 (OR = 59.84), confirmed as a significant marker with an AUC of 0.78. Furthermore, the CST on the affected side significantly had the greater irregularity, larger TRER and RER 1, and smaller span compared to the healthy side. DATA CONCLUSION: Preoperative evaluation of TRER and IER 1 metrics in the CST may serve as a tool for assessing the risk of postoperative motor complications in insular LGG patients. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.

Single-pulse transcranial magnetic stimulation for assessment of motor development in infants with early brain injury.

INTRODUCTION: Single-pulse transcranial magnetic stimulation (TMS) has many applications for pediatric clinical populations, including infants with perinatal brain injury. As a noninvasive neuromodulation tool, single-pulse TMS has been used safely in infants and children to assess corticospinal integrity and circuitry patterns. TMS may have important applications in early detection of atypical motor development or cerebral palsy. AREAS COVERED: The authors identified and summarized relevant studies incorporating TMS in infants, including findings related to corticospinal development and circuitry, motor cortex localization and mapping, and safety. This special report also describes methodologies and safety considerations related to TMS assessment in infants, and discusses potential applications related to diagnosis of cerebral palsy and early intervention. EXPERT OPINION: Single-pulse TMS has demonstrated safety and feasibility in infants with perinatal brain injury and may provide insight into neuromotor development and potential cerebral palsy diagnosis. Additional research in larger sample sizes will more fully evaluate the utility of TMS biomarkers in early diagnosis and intervention. Methodological challenges to performing TMS in infants and technical/equipment limitations require additional consideration and innovation toward clinical implementation. Future research may explore use of noninvasive neuromodulation techniques as an intervention in younger children with perinatal brain injury to improve motor outcomes.

Single pulse transcranial magnetic stimulation (TMS) is a safe and noninvasive way to study brain activity in infants and children who have experienced brain injuries around the time of birth. Infants who have had an early brain injury may develop cerebral palsy, a developmental disability that affects movement. TMS uses a device that gives single pulses of energy to activate specific areas of the brain. This can be used to study how the brain connects to the muscles in the body through paths or 'tracts.' TMS helps researchers understand the development of the tracts and the potential need for therapy. This article reviews research studies that used TMS in infants and explains how TMS can be used to assess brain development. It also reviews safety considerations and challenges related to using TMS in infants. TMS could be a valuable tool for early diagnosis of cerebral palsy and could also help guide treatments for infants with brain injuries. However, more research is needed, using larger groups of infants, to potentially expand the use of TMS in clinical practice. Future directions include developing infant-specific research tools and using noninvasive brain stimulation to improve recovery for infants with brain injuries.

Corticospinal tract: a new hope for the treatment of post-stroke spasticity.

Stroke is the third leading cause of death and disability worldwide. Post-stroke spasticity (PSS) is the most common complication of stroke but represents only one of the many manifestations of upper motor neuron syndrome. As an upper motor neuron, the corticospinal tract (CST) is the only direct descending motor pathway that innervates the spinal motor neurons and is closely related to the recovery of limb function in patients with PSS. Therefore, promoting axonal remodeling in the CST may help identify new therapeutic strategies for PSS. In this review, we outline the pathological mechanisms of PSS, specifically their relationship with CST, and therapeutic strategies for axonal regeneration of the CST after stroke. We found it to be closely associated with astroglial scarring produced by astrocyte activation and its secretion of neurotrophic factors, mainly after the onset of cerebral ischemia. We hope that this review offers insight into the relationship between CST and PSS and provides a basis for further studies.

Anti-motion Ultrafast T2 Mapping Technique for Quantitative Detection of the Normal-Appearing Corticospinal Tract Changes in Subacute-Chronic Stroke Patients with Distal Lesions.

RATIONALE AND OBJECTIVES: Stroke patients commonly face challenges during magnetic resonance imaging (MRI) examinations due to involuntary movements. This study aims to overcome these challenges by utilizing multiple overlapping-echo detachment (MOLED) quantitative technology. Through this technology, we also seek to detect microstructural changes of the normal-appearing corticospinal tract (NA-CST) in subacute-chronic stroke patients. MATERIALS AND METHODS: 79 patients underwent 3.0 T MRI scans, including routine scans and MOLED technique. A deep learning network was utilized for image reconstruction, and the accuracy, reliability, and resistance to motion of the MOLED technique were validated on phantoms and volunteers. Subsequently, we assessed motor dysfunction severity, ischemic lesion volume, T2 values of the bilateral NA-CST, and the T2 ratio (rT2) between the ipsilesional and contralesional NA-CST in patients. RESULTS: The MOLED technique showed high accuracy (P < 0.001) and excellent repeatability, with a mean coefficient of variation (CoV) of 1.11%. It provided reliable quantitative results even under head movement, with a mean difference (Meandiff)= 0.28% and a standard deviation difference (SDdiff)= 1.34%. Additionally, the T2 value of the ipsilesional NA-CST was significantly higher than contralesional side (P < 0.001), and a positive correlation was observed between rT2 and the severity of motor dysfunction (rs =0.575, P < 0.001). Furthermore, rT2 successfully predicted post-stroke motor impairment, with an area under the curve (AUC) was 0.883. CONCLUSION: The MOLED technique offers significant advantages for quantitatively imaging stroke patients with involuntary movements. Additionally, T2 mapping from MOLED can detect microstructural changes in the NA-CST, potentially aiding in monitoring stroke-induced motor impairment.