Stroke can cause Wallerian degeneration in regions outside of the brain,particularly in the corticospinal tract.To investigate the fate of major glial cells and axons within affected areas of the corticospinal tract f...Stroke can cause Wallerian degeneration in regions outside of the brain,particularly in the corticospinal tract.To investigate the fate of major glial cells and axons within affected areas of the corticospinal tract following stroke,we induced photochemical infarction of the sensorimotor cortex leading to Wallerian degeneration along the full extent of the corticospinal tract.We first used a routine,sensitive marker of axonal injury,amyloid precursor protein,to examine Wallerian degeneration of the corticospinal tract.An antibody to amyloid precursor protein mapped exclusively to proximal axonal segments within the ischemic cortex,with no positive signal in distal parts of the corticospinal tract,at all time points.To improve visualization of Wallerian degeneration,we next utilized an orthograde virus that expresses green fluorescent protein to label the corticospinal tract and then quantitatively evaluated green fluorescent protein-expressing axons.Using this approach,we found that axonal degeneration began on day 3 post-stroke and was almost complete by 7 days after stroke.In addition,microglia mobilized and activated early,from day 7 after stroke,but did not maintain a phagocytic state over time.Meanwhile,astrocytes showed relatively delayed mobilization and a moderate response to Wallerian degeneration.Moreover,no anterograde degeneration of spinal anterior horn cells was observed in response to Wallerian degeneration of the corticospinal tract.In conclusion,our data provide evidence for dynamic,pathogenic spatiotemporal changes in major cellular components of the corticospinal tract during Wallerian degeneration.展开更多
Stroke causes long-term disability, and rehabilitative training is commonly used to improve the consecutive functional recovery. Following brain damage, surviving neurons undergo morphological alterations to reconstru...Stroke causes long-term disability, and rehabilitative training is commonly used to improve the consecutive functional recovery. Following brain damage, surviving neurons undergo morphological alterations to reconstruct the remaining neural network. In the motor system, such neural network remodeling is observed as a motor map reorganization. Because of its significant correlation with functional recovery, motor map reorganization has been regarded as a key phenomenon for functional recovery after stroke. Although the mechanism underlying motor map reorganization remains unclear, increasing evidence has shown a critical role for axonal remodeling in the corticospinal tract. In this study, we review previous studies investigating axonal remodeling in the corticospinal tract after stroke and discuss which mechanisms may underlie the stimulatory effect of rehabilitative training. Axonal remodeling in the corticospinal tract can be classified into three types based on the location and the original targets of corticospinal neurons, and it seems that all the surviving corticospinal neurons in both ipsilesional and contralesional hemisphere can participate in axonal remodeling and motor map reorganization. Through axonal remodeling, corticospinal neurons alter their output selectivity from a single to multiple areas to compensate for the lost function. The remodeling of the corticospinal axon is influenced by the extent of tissue destruction and promoted by various therapeutic interventions, including rehabilitative training. Although the precise molecular mechanism underlying rehabilitation-promoted axonal remodeling remains elusive, previous data suggest that rehabilitative training promotes axonal remodeling by upregulating growth-promoting and downregulating growth-inhibiting signals.展开更多
Stroke remains the leading cause of long-term disability.Hemiparesis is one of the most common post-stroke motor deficits and is largely attributed to loss or disruption of the motor signals from the affected motor co...Stroke remains the leading cause of long-term disability.Hemiparesis is one of the most common post-stroke motor deficits and is largely attributed to loss or disruption of the motor signals from the affected motor cortex.As the only direct descending motor pathway,the corticospinal tract(CST)is the primary pathway to innervate spinal motor neurons,and thus,forms the neuroanatomical basis to control the peripheral muscles for voluntary movements.Here,we review evidence from both experimental animals and stroke patients,regarding CST axonal damage,functional contribution of CST axonal integrity and remodeling to neurological recovery,and therapeutic approaches aimed to enhance CST axonal remodeling after stroke.The new insights gleaned from preclinical and clinical studies may encourage the development of more rational therapeutics with a strategy targeted to promote axonal rewiring for corticospinal innervation,which will significantly impact the current clinical needs of subacute and chronic stroke treatment.展开更多
As most spinal cord injuries(SCIs) are incomplete,an important target for promoting neural repair and recovery of lost motor function is to promote the connections of spared descending spinal pathways with spinal moto...As most spinal cord injuries(SCIs) are incomplete,an important target for promoting neural repair and recovery of lost motor function is to promote the connections of spared descending spinal pathways with spinal motor circuits.Among the pathways,the corticospinal tract(CST) is most associated with skilled voluntary functions in humans and many animals.CST loss,whether at its origin in the motor cortex or in the white matter tracts subcortically and in the spinal cord,leads to movement impairments and paralysis.To restore motor function after injury will require repair of the damaged CST.In this review,I discuss how knowledge of activity-dependent development of the CST—which establishes connectional specificity through axon pruning,axon outgrowth,and synaptic competition among CST terminals—informed a novel activity-based therapy for promoting sprouting of spared CST axons after injur in mature animals.This therapy,which comprises motor cortex electrical stimulation with and without concurrent trans-spinal direct current stimulation,leads to an increase in the gray matter axon length of spared CST axons in the rat spinal cord and,after a pyramidal tract lesion,restoration of skilled locomotor movements.I discuss how this approach is now being applied to a C4 contusion rat model.展开更多
BACKGROUND: Diffusion tensor imaging (DTI) is one of the noninvasive methods to study the morphological structure of brain white matter fibrous bands in vivo, and it has been applied primarily in clinic. DTI is acknow...BACKGROUND: Diffusion tensor imaging (DTI) is one of the noninvasive methods to study the morphological structure of brain white matter fibrous bands in vivo, and it has been applied primarily in clinic. DTI is acknowledged as the more effective imaging method to diagnose ultra-acute and/or acute cerebral infarction. OBJECTIVE: To observe the anisotropic characters of cerebral white matter fibrous bands in patients with ischemic stroke by using DTI, and investigate the correlation between the damage of corticospinal tract and muscle strength in patients with ischemic stroke at acute period. DESIGN: A case-control observation. SETTING: Department of Medical Imaging, Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA. PARTICIPANTS: Nine inpatients with injury of motor function induced by acute ischemic stroke (patient group) at 6 hours to 2 weeks after the attack were selected from the Department of Neurology, Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA from September 2005 to March 2006, and they all accorded with the present diagnostic standard for cerebrovascular disease in China. There were 5 males and 4 females, aged 16-87 years. At the same time, nine healthy right-handed physical examinees matched by age and sex with the patients were taken as the control group, and they all had no nervous disease, mental diseases, cerebrovascular abnormalities and injury history, etc. All the subjects were informed with the detected items and agreed to participate in the study. METHODS: All the 9 patients with ischemic stroke at acute period and 9 healthy subjects were examined with MRI, T1 weighted imaging, T2 weighted imaging and DTI. And the data were processed offline with dTV.II software, the images of fractional anisotropy and directional encoded color (DEC) were obtained, and the three-dimensional fibrous band images of bilateral corticospinal tracts were reconstructed. In the control group, the values of fractional anisotropy of main white matter fibrous bands were measured in the region of interest (ROI) of the anterior limb, knee and posterior limb of internal capsule. In the patient group, the values of fractional anisotropy of white matter were measured in the infarcted sites and corresponding contralateral sites of the patients. The ROI was set in bilateral cerebral peduncles to reconstruct three-dimensionally the bilateral corticospinal tracts. The muscle strength of the affected hand was assessed with Brunnstorm standard in the stroke patients. MAIN OUTCOME MEASURES: The characters of DTI and images of the value of fractional anisotropy, and the manifestations of three-dimensional corticospinal tracts were observed in the two groups. RESULTS: All the data from the 9 patients and 9 healthy volunteers were involved in the analysis of results. ① In the control group, the white matter and gray matter could be distinguished clearly in the image of fractional anisotropic values, the fibers of different directions were shown by different colors in DEC picture, which clearly demonstrated the normal anatomic structure and direction of white matter fibers. In the patient group, the infarctions occurred in the gray matter or white matter could be distinguished in the images of fractional anisotropic values, DEC picture could clearly show the direct influence of the infarcted site on the white matter fibers. The fractional anisotropic values in different white matter structure of the same side were significantly different in the control group (t=3.12, P < 0.05), and the reconstructed images fractional anisotropic values and DEC picture could show most of the main white matter fibrous bands. The fractional anisotropic values of the infarcted sites were significantly lower than the contralateral ones in the patient group (t=5.570, P < 0.01). ② The reconstructed bilateral corticospinal tracts showed that the anatomic forms of the contralateral corticospinal tract of the patients were almost identical to those of normal people, it started from precentral gyrus, downward to the nternal capsule, and extended to pontine and medulla oblongata, each fibrous band was continuous, and the form had good consistency. Because of the involvement of infarction of different severity, the ipsilateral corticospinal tract manifested as continuous interruption and the loss of consistent anatomic structural form. The involved severity of corticospinal tract had significant correlation with that of muscle strength of the ipsilateral hand (r=1.30, P < 0.01). CONCLUSION: ① DTI can display the direction and distribution of cerebral white matter fibrous bands. ② DTI images of fractional anisotropic values and DEC can show the directions and anisotropic degree of white matter fibers in the infarcted sites of stroke patients. ③ The three-dimensional images of fibrous bands can show the conditions of pyramidal tracts more directly. ④ The damaged severity of corticospinal tracts is correlated with that of muscle strength.展开更多
BACKGROUND: There are many methods for myelin staining,mordant,or the special reaction of osmic acid with lipoid is used according to different principles.The commonly used methods are classic Well staining ,classic l...BACKGROUND: There are many methods for myelin staining,mordant,or the special reaction of osmic acid with lipoid is used according to different principles.The commonly used methods are classic Well staining ,classic lithium carbonate-haematine staining,fast green staining,silver staining ,etc.Luxol Fast Blue can brightly stain myelin sheath,and has certain specificity .The background can be very clean if there is proper differentiation,whereas Luxol Fast Blue is cheap and convenient to operate,thus it is an ideal staining reagent for routine myelin sheath.OBJECTIVE: To show the coricospinal tract of normal adult rats with Luxol Fast Blue shaining method.DESIGN:A repetitive measurement design.SETTINGS: Institute of Nuerobiology,Nantong University;Department of Rehabilitation Medicine,Affiliated Hospital of Nantong University.MATERIALS: Six healthy adult male SD rats of clean dergree,weighing averagely 300 g.were provided by the experimental animal center of Nantong University.1 g/L Luxol Fast Blue solution was provided by Sigma Company;Leica CM1900 cryostat microtome by Leica Company;Leica DMR microscope by Leica Company.METHODS:The experiment was carried out in the Staff Room of Human Anatomy,Nantong University in May 2005.The rats were given intraperitoneal injection of combined anesthetic(2 mL/kg),then the chest was open for perfusing saline and phosphate buffer containing formamint via heart. Brain and spinal cord were removed after 1 hour then fixed,then changed to phosphate buffer(pH 7.4)containing 300 g/L saccharu at 4 ℃.and stayed overnight,tissue blocks at pyramid,decussation of pyramid and cervical,thoracic,lumbar and sacral segments of spinal cord were removed to prepare continuous horizontal frozen sections(30 μm) after sedimentation,the sections were dried at room temperature.The corticospinal tract of normal adult rats were shown with Luxol Fast Blue staining method,and observed under Leica DMR microscope.MAIN OUTCOME MEASURES:Positive fibers in Luxol Fast Blue staining.RESULTS:After the Luxol Fast Blue staining,the labeled myelinated nerve fibers were bright blue.They located in the pyramid,decussation of pyramid and the ventral part of posterior funiculus in cervical,thoracic,lumbar and sacral segments of spinal cord.CONCLUSION:Luxol Fast Blue staining method may manifest the distribution of corticospinal tract with clear distinct in adult rats.展开更多
Application of continuous repetition of motor imagery can improve the performance of exercise tasks.However,there is a lack of more detailed neurophysiological evidence to support the formulation of clear standards fo...Application of continuous repetition of motor imagery can improve the performance of exercise tasks.However,there is a lack of more detailed neurophysiological evidence to support the formulation of clear standards for interventions using motor imagery.Moreover,identification of motor imagery intervention time is necessary because it exhibits possible central fatigue.Therefore,the purpose of this study was to elucidate the development of fatigue during continuous repetition of motor imagery through objective and subjective evaluation.The study involved two experiments.In experiment 1,14 healthy young volunteers were required to imagine grasping and lifting a 1.5-L plastic bottle using the whole hand.Each participant performed the motor imagery task 100 times under each condition with 48 hours interval between two conditions:500 mL or 1500 mL of water in the bottle during the demonstration phase.Mental fatigue and a decrease in pinch power appeared under the 1500-mL condition.There were changes in concentration ability or corticospinal excitability,as assessed by motor evoked potentials,between each set with continuous repetition of motor imagery also under the 1500-mL condition.Therefore,in experiment 2,12 healthy volunteers were required to perform the motor imagery task 200 times under the 1500-mL condition.Both concentration ability and corticospinal excitability decreased.This is the first study to show that continuous repetition of motor imagery can decrease corticospinal excitability in addition to producing mental fatigue.This study was approved by the Institutional Ethics Committee at the Nagasaki University Graduate School of Biomedical and Health Sciences(approval No.18121302)on January 30,2019.展开更多
The corticospinal tract(CST)is a major neural tract for motor function in the human brain.In addition,CST is mainly concerned with execution of movement of the hand(Jang,2014).However,few studies are reported on the m...The corticospinal tract(CST)is a major neural tract for motor function in the human brain.In addition,CST is mainly concerned with execution of movement of the hand(Jang,2014).However,few studies are reported on the mechanism underlying CST recovery after traumatic brain injury(Seo and Jang,2015).In this study,we report on a case that showed recovery of an injured CST by traumatic展开更多
BACKGROUND: Three-dimensional diffusion tensor tract (DTT) is the newest imaging to describe the structure of white matter fiber in three-dimensions, it has great significance in dividing the concrete anatomic site of...BACKGROUND: Three-dimensional diffusion tensor tract (DTT) is the newest imaging to describe the structure of white matter fiber in three-dimensions, it has great significance in dividing the concrete anatomic site of gray and white matter lesions, displaying the correlation with fibrous band and judging clinical prognosis, which is incomparable by other imagings. OBJECTIVE: To observe the conditions of corticospinal tract (CST) in acute cerebral ischemic stroke patients, and analyze the relationship between motor function and the severity of CST injury. DESIGN: A case-control observation. SETTING: Department of Medical Imaging, Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA. PARTICIPANTS: Fifteen patients with acute cerebral infarction were selected from Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA from February to December in 2005. They all suffered from acute attack and motor disorder of hemiplegic limbs to different extent, and were conformed by CT or MRI. There were 9 males and 6 females, aging 16-87 years old, the median age was 51.7 years, and all were right handed. Fifteen right-handed normal subjects, who were matched by age and sex with the patients in the cerebral infarction group, were selected from the relatives of patients and physicians of the Imaging Department as the control group. All the subjects were informed and agreed with the study. METHODS: The patients with acute cerebral infarction and subjects in the control group received MR diffusion tensor imaging (DTI) with GE 1.5 T nuclear magnetic resonance system, fiber tracking with the software of dTV-Ⅱ. Fractional anisotropy (FA) maps and three-dimensional tractography of bilateral CST of all patients were created. Displacement, continuity and destroy of fibrous bands were observed. At the same time, muscle strength of ipsilateral hand of patients with cerebral infarction was measured with Brunnstrom standard. The correlation between the severity of CST injury and the muscle strength of ipsilateral hand was analyzed with spearman correlation analysis. MAIN OUTCOME MEASURES: ① FA values in the infarcted sites and those in the contralateral corresponding sites of patients with cerebral infarction; ② CST manifestations in the patients with cerebral infarction and the control group. RESULTS: All the 30 testees were involved in the analysis of results. ① The FA values in infarcted sites of white matter were significantly lower than those in the contralateral ones (t =4.570,P < 0.001). ② In the control group, bilateral CST were reconstructed, they originated from precentral gyrus, went downwards to internal capsule, and extended to pontine and medulla oblongata, each fiber had good uniformity in continuous form. In the patients with cerebral infarction, the forms of contralateral CST were consistent with those in the control group with good continuity. Due to the involvement by the infarcted site to different extents, the ipsilateral CST manifested as continuous interruption and loss of uniformity in anatomic structure and form. The CST involvements were divided into three grades: integrated CST for grade 1 (n =2); integrated CST but compressed or displaced for grade 2 (n =5); interrupted CST for grade 3 (n =8). ③ The severity of CST injury was obviously correlated with the muscle strength of the ipsilateral hand (r =0.888, P < 0.05). CONCLUSION: ① CST is injured to different extents in patients with acute cerebral infarction, and the severity of injury is associated with muscle strength. It is indicated that it can be used to judge the prognosis of rehabilitative treatment. ②DTT can directly display the status of pyramidal tract more three-dimensionally.展开更多
Objectives: The aim of the study is to assess volumetric Corticospinal Tract infiltration by Astro-cytoma using Diffusion Tensor Tractography. Material and Methods: Preoperative, anatomic (T1- and T2-weighted) and dif...Objectives: The aim of the study is to assess volumetric Corticospinal Tract infiltration by Astro-cytoma using Diffusion Tensor Tractography. Material and Methods: Preoperative, anatomic (T1- and T2-weighted) and diffusion tensor MRI were performed in 9 patients with supratentorial gliomas (WHO grade II and III). The tumors were manually segmented from the T1- and T2-weighted MRI, and their volume calculated. A three-dimensional tractography was performed in each case. A second segmentation and volume measurement was performed on the tumor regions intersecting adjacent white matter fiber tracts. Results: We identified that white matter tracts were infiltrated by 6 Astrocytoma tumors. The median tumor volume (±standard deviation) in our patient population was 33 ± 26.82 ml. The median tumor volume (±standard deviation) infiltrating white matter fiber tracts was 4.15 ± 9.23 ml. The median fraction of tumor volume infiltrating white matter fiber tracts was 26.3% ± 10.1%. Conclusions: Diffusion tensor MR Tractography is a reliable preoperative assessment tool since it detects extensive white matter infiltration by Astrocytoma irrespective of brain tumors volume. Recommendations: Prospective large population studies are required to clarify how infiltration relates to tumor location.展开更多
To investigate the feasibility and time window of early detection of Wallerian degeneration in the corticospinal tract after middle cerebral artery infarction,23 patients were assessed using magnetic resonance diffusi...To investigate the feasibility and time window of early detection of Wallerian degeneration in the corticospinal tract after middle cerebral artery infarction,23 patients were assessed using magnetic resonance diffusion tensor imaging at 3.0T within 14 days after the infarction.The fractional anisotropy values of the affected corticospinal tract began to decrease at 3 days after onset and decreased in all cases at 7 days.The diffusion coefficient remained unchanged.Experimental findings indicate that diffusion tensor imaging can detect the changes associated with Wallerian degeneration of the corticospinal tract as early as 3 days after cerebral infarction.展开更多
Although neuroimaging is commonly utilized to study Wallerian degeneration,it cannot display Wallerian degeneration early after brain injury.In the present study,we attempted to examine pathologically the process of W...Although neuroimaging is commonly utilized to study Wallerian degeneration,it cannot display Wallerian degeneration early after brain injury.In the present study,we attempted to examine pathologically the process of Wallerian degeneration early after brain injury.Cerebral peduncle demyelination was observed at 3 weeks post brain ischemia,followed by demyelination in the cervical enlargement at 6 weeks.Anterograde tracing of the corticospinal tract with biotinylated dextran amine showed that following serious neurologic deficit,the tracing of the corticospinal tract of the internal capsule,cerebral peduncle,and cervical enlargement indicated serious Wallerian degeneration.展开更多
The corticospinal tract(CST) is one of the most important neural tracts for motor function in the human brain.Little is known about age-related changes of the CST.In this study,we tried to evaluate age-related changes...The corticospinal tract(CST) is one of the most important neural tracts for motor function in the human brain.Little is known about age-related changes of the CST.In this study,we tried to evaluate age-related changes of the CST using diffusion tensor imaging in 60 healthy subjects.The diffusion tensor imaging result revealed that the tract number and fractional anisotropy value were decreased,and the apparent diffusion coefficient(ADC) value was increased with aging.The distribution showed a semilog pattern for tract number,fractional anisotropy and ADC of the CST,and the pattern of each graph was near-linear.When compared with the diffusion tensor imaging parameters of subjects in the 20 s age group,tract number and fractional anisotropy values were significantly decreased in the 50 s-70 s age groups.Likewise,the ADC value was significantly higher in the 50 s-70 s age groups.The CST in the brain of normal subjects degenerated continuously from the 20 s to the 70 s,with a near-linear pattern,and degeneration of the CST began to manifest significantly in the subjects in their 50 s,compared with the subjects in their 20 s.展开更多
The present study investigated the effects of Fujian tablet, a Chinese medicine compound that can nourish liver and kidney, on corticospinal tract plasticity and cervical cord microenvironment in rats with focal cereb...The present study investigated the effects of Fujian tablet, a Chinese medicine compound that can nourish liver and kidney, on corticospinal tract plasticity and cervical cord microenvironment in rats with focal cerebral ischemia. Results showed that motor function of rats with right proximal middle cerebral artery occlusion was significantly improved following treatment with Fujian tablet, 9 g crude drug/kg. Anterograde tracing revealed significantly increased biotinylated dextran amine expression in the denervated (left) side of the cervical cord (C4-6) following Fujian tablet treatment, and significantly decreased Nogo-A mRNA expression was detected in the denervated side of the cervical cord (C4-6) using in situ hybridization. Pearson's correlation analysis showed a negative correlation between biotinylated dextran amine and Nogo-A mRNA expression (r = -0.943, P < 0.01). Results demonstrated that Fujian tablet can promote corticospinal tract plasticity possibly through the inhibitory effect on Nogo-A mRNA expression in the cervical spinal cord, thereby improving motor dysfunction.展开更多
In this study, biotinylated dextran amine (BDA) was microinjected into the left cortical motor area of the canine brain. Fluorescence microscopy results showed that a large amount of BDA-labeled pyramidal cells were v...In this study, biotinylated dextran amine (BDA) was microinjected into the left cortical motor area of the canine brain. Fluorescence microscopy results showed that a large amount of BDA-labeled pyramidal cells were visible in the left cortical motor area after injection. In the left medulla oblongata, the BDA-labeled corticospinal tract was evenly distributed, with green fluorescence that had a clear boundary with the surrounding tissue. The BDA-positive corticospinal tract entered into the right lateral funiculus of the spinal cord and descended into the posterior part of the right lateral funiculus, close to the posterior horn, from cervical to sacral segments. There was a small amount of green fluorescence in the sacral segment. The distribution of BDA labeling in the canine central nervous system was consistent with the course of the corticospinal tract. Fluorescence labeling for BDA gradually diminished with time after injection. Our findings indicate that the BDA anterograde tracing technique can be used to visualize the localization and trajectory of the corticospinal tract in the canine central nervous system.展开更多
Subdural hematoma can cause compression or damage to the neural tracts in the brain; however, very little is known about this injury. We report on a patient with subdural hematoma who was evaluated by diffusion tensor...Subdural hematoma can cause compression or damage to the neural tracts in the brain; however, very little is known about this injury. We report on a patient with subdural hematoma who was evaluated by diffusion tensor imaging prior to and after trephination and drainage of subdural hematoma. A 58-year-old male patient and ten age-matched normal control subjects were evaluated. The patient showed mild hemiparesis for 3 weeks prior to surgery. His hemiparesis recovered to a nearly normal state at 5 weeks post-surgery when the follow up diffusion tensor image was acquired. Two diffusion tensor image parameters, fractional anisotropy and apparent diffusion coefficient, were measured along the corticospinal tract. Pre-operative diffusion tensor image showed that the corticospinal tract of the affected hemisphere seemed to be injured or compressed. However, the follow up diffusion tensor image showed recovery of this corticospinal tract to a normal state. It would appear that diffusion tensor images are a useful tool for evaluation of the effects of subdural hematomas on neural tracts.展开更多
Many studies have attempted to elucidate the motor recovery mechanism of stroke,but the majority of these studies focus on cerebral infarct and relatively little is known about the motor recovery mechanism of intracer...Many studies have attempted to elucidate the motor recovery mechanism of stroke,but the majority of these studies focus on cerebral infarct and relatively little is known about the motor recovery mechanism of intracerebral hemorrhage.In this study,we report on a patient with intracerebral hemorrhage who displayed a change in injured corticospinal tract originating from the premotor cortex to the primary motor cortex on diffusion tensor imaging.An 86-year-old woman presented with complete paralysis of the right extremities following spontaneous intracerebral hemorrhage in the left frontoparietal cortex.The patient showed motor recovery,to the extent of being able to extend affected fingers against gravity and to walk independently on even ground at 5 months after onset.Diffusion tensor imaging showed that the left corticospinal tract originated from the premotor cortex at 1 month after intracerebral hemorrhage and from the left primary motor cortex and premotor cortex at 5 months after intracerebral hemorrhage.The change of injured corticospinal tract originating from the premotor cortex to the primary motor cortex suggests motor recovery of intracerebral hemorrhage.展开更多
Following central nervous system injury, axonal sprouts form distal to the injury site and extend into the denervated area, reconstructing neural circuits through neural plasticity. How to facilitate this plasticity h...Following central nervous system injury, axonal sprouts form distal to the injury site and extend into the denervated area, reconstructing neural circuits through neural plasticity. How to facilitate this plasticity has become the key to the success of central nervous system repair. It remains controversial whether fine motor skill training contributes to the recovery of neurological function after spinal cord injury. Therefore, we established a rat model of unilateral corticospinal tract injury using a pyramidal tract cutting method. Horizontal ladder crawling and food ball grasping training procedures were conducted 2 weeks before injury and 3 days after injury. The neurological function of rat forelimbs was assessed at 1, 2, 3, 4, and 6 weeks after injury. Axon growth was observed with biotinylated dextran amine anterograde tracing in the healthy corticospinal tract of the denervated area at different time periods. Our results demonstrate that compared with untrained rats, functional recovery was better in the forelimbs and forepaws of trained rats. The number of axons and the expression of growth associated protein 43 were increased at the injury site 3 weeks after corticospinal tract injury. These findings confirm that fine motor skill training promotes central nervous system plasticity in spinal cord injury rats.展开更多
Integrity of the corticospinal tract is mandatory for good recovery of impaired motor function in patients who have suffered a stroke. A 67-year-old left hemiparetic female showed an infarct in the right pons. Three m...Integrity of the corticospinal tract is mandatory for good recovery of impaired motor function in patients who have suffered a stroke. A 67-year-old left hemiparetic female showed an infarct in the right pons. Three months after onset, motor function of the affected extremities recovered rapidly to a nearly complete state. Diffusion tensor tractography of both hemispheres showed that the corticospinal tract originated from the primary sensori-motor cortex and descended through the known corticospinal tract pathway. The tract of the affected (right) hemisphere descended through an area within the pontine infarct. The diffusion tensor tractography results suggest that from the onset, the integrity of the corticospinal tract appears to have been spared within the pontine infarct.展开更多
The present study reported a 42-year-old male patient who underwent conservative management for a spontaneous intracerebral hemorrhage in the left corona radiata and the basal ganglia.The patient presented with comple...The present study reported a 42-year-old male patient who underwent conservative management for a spontaneous intracerebral hemorrhage in the left corona radiata and the basal ganglia.The patient presented with complete weakness of the right upper and lower extremities at the onset of intracerebral hemorrhage;however,he showed progressive motor recovery to the level that he was able to extent the affected extremities against some resistance at 5 weeks after onset.The corticospinal tract of the affected (left) hemisphere connected to the left Broca's area at 3 weeks after onset as shown by diffusion tensor tractography.By contrast,this connection had disappeared at 5 weeks after onset as shown by diffusion tensor tractogaphy.Transcranial magnetic stimulation study showed that no motor evoked potential was elicited from the affected (left) hemisphere at 3 weeks after onset,but motor evoked potentials were elicited at 5 weeks after onset.These findings suggest that the connection between the injured corticospinal tract and Broca's area in this patient appears to be a compensation for severe motor weakness;consequently,the connection seems to disappear with motor recovery.展开更多
基金supported by the National Natural Science Foundation of China,Nos.31 730030 (to XL),81941011 (to XL),31 771053 (to HD),82271403 (to XL),82272171 (to ZY),31971279 (to ZY)82201542 (to FH)+1 种基金the Natural Science Foundation of Beijing,No.7222004 (to HD)the Science and Technology Program of Beijing,No.Z181100001818007(to ZY)
文摘Stroke can cause Wallerian degeneration in regions outside of the brain,particularly in the corticospinal tract.To investigate the fate of major glial cells and axons within affected areas of the corticospinal tract following stroke,we induced photochemical infarction of the sensorimotor cortex leading to Wallerian degeneration along the full extent of the corticospinal tract.We first used a routine,sensitive marker of axonal injury,amyloid precursor protein,to examine Wallerian degeneration of the corticospinal tract.An antibody to amyloid precursor protein mapped exclusively to proximal axonal segments within the ischemic cortex,with no positive signal in distal parts of the corticospinal tract,at all time points.To improve visualization of Wallerian degeneration,we next utilized an orthograde virus that expresses green fluorescent protein to label the corticospinal tract and then quantitatively evaluated green fluorescent protein-expressing axons.Using this approach,we found that axonal degeneration began on day 3 post-stroke and was almost complete by 7 days after stroke.In addition,microglia mobilized and activated early,from day 7 after stroke,but did not maintain a phagocytic state over time.Meanwhile,astrocytes showed relatively delayed mobilization and a moderate response to Wallerian degeneration.Moreover,no anterograde degeneration of spinal anterior horn cells was observed in response to Wallerian degeneration of the corticospinal tract.In conclusion,our data provide evidence for dynamic,pathogenic spatiotemporal changes in major cellular components of the corticospinal tract during Wallerian degeneration.
基金supported by the JSPSKAKENHI Grant-in-Aid for Scientific Research(B),Grant Numbers24700572 and 30614276
文摘Stroke causes long-term disability, and rehabilitative training is commonly used to improve the consecutive functional recovery. Following brain damage, surviving neurons undergo morphological alterations to reconstruct the remaining neural network. In the motor system, such neural network remodeling is observed as a motor map reorganization. Because of its significant correlation with functional recovery, motor map reorganization has been regarded as a key phenomenon for functional recovery after stroke. Although the mechanism underlying motor map reorganization remains unclear, increasing evidence has shown a critical role for axonal remodeling in the corticospinal tract. In this study, we review previous studies investigating axonal remodeling in the corticospinal tract after stroke and discuss which mechanisms may underlie the stimulatory effect of rehabilitative training. Axonal remodeling in the corticospinal tract can be classified into three types based on the location and the original targets of corticospinal neurons, and it seems that all the surviving corticospinal neurons in both ipsilesional and contralesional hemisphere can participate in axonal remodeling and motor map reorganization. Through axonal remodeling, corticospinal neurons alter their output selectivity from a single to multiple areas to compensate for the lost function. The remodeling of the corticospinal axon is influenced by the extent of tissue destruction and promoted by various therapeutic interventions, including rehabilitative training. Although the precise molecular mechanism underlying rehabilitation-promoted axonal remodeling remains elusive, previous data suggest that rehabilitative training promotes axonal remodeling by upregulating growth-promoting and downregulating growth-inhibiting signals.
文摘Stroke remains the leading cause of long-term disability.Hemiparesis is one of the most common post-stroke motor deficits and is largely attributed to loss or disruption of the motor signals from the affected motor cortex.As the only direct descending motor pathway,the corticospinal tract(CST)is the primary pathway to innervate spinal motor neurons,and thus,forms the neuroanatomical basis to control the peripheral muscles for voluntary movements.Here,we review evidence from both experimental animals and stroke patients,regarding CST axonal damage,functional contribution of CST axonal integrity and remodeling to neurological recovery,and therapeutic approaches aimed to enhance CST axonal remodeling after stroke.The new insights gleaned from preclinical and clinical studies may encourage the development of more rational therapeutics with a strategy targeted to promote axonal rewiring for corticospinal innervation,which will significantly impact the current clinical needs of subacute and chronic stroke treatment.
基金Support provided by grants from the National Institutes of Health R01NS064004the New York State Department of Health Spinal Cord Injury Board C30606GG,C30835GG
文摘As most spinal cord injuries(SCIs) are incomplete,an important target for promoting neural repair and recovery of lost motor function is to promote the connections of spared descending spinal pathways with spinal motor circuits.Among the pathways,the corticospinal tract(CST) is most associated with skilled voluntary functions in humans and many animals.CST loss,whether at its origin in the motor cortex or in the white matter tracts subcortically and in the spinal cord,leads to movement impairments and paralysis.To restore motor function after injury will require repair of the damaged CST.In this review,I discuss how knowledge of activity-dependent development of the CST—which establishes connectional specificity through axon pruning,axon outgrowth,and synaptic competition among CST terminals—informed a novel activity-based therapy for promoting sprouting of spared CST axons after injur in mature animals.This therapy,which comprises motor cortex electrical stimulation with and without concurrent trans-spinal direct current stimulation,leads to an increase in the gray matter axon length of spared CST axons in the rat spinal cord and,after a pyramidal tract lesion,restoration of skilled locomotor movements.I discuss how this approach is now being applied to a C4 contusion rat model.
文摘BACKGROUND: Diffusion tensor imaging (DTI) is one of the noninvasive methods to study the morphological structure of brain white matter fibrous bands in vivo, and it has been applied primarily in clinic. DTI is acknowledged as the more effective imaging method to diagnose ultra-acute and/or acute cerebral infarction. OBJECTIVE: To observe the anisotropic characters of cerebral white matter fibrous bands in patients with ischemic stroke by using DTI, and investigate the correlation between the damage of corticospinal tract and muscle strength in patients with ischemic stroke at acute period. DESIGN: A case-control observation. SETTING: Department of Medical Imaging, Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA. PARTICIPANTS: Nine inpatients with injury of motor function induced by acute ischemic stroke (patient group) at 6 hours to 2 weeks after the attack were selected from the Department of Neurology, Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA from September 2005 to March 2006, and they all accorded with the present diagnostic standard for cerebrovascular disease in China. There were 5 males and 4 females, aged 16-87 years. At the same time, nine healthy right-handed physical examinees matched by age and sex with the patients were taken as the control group, and they all had no nervous disease, mental diseases, cerebrovascular abnormalities and injury history, etc. All the subjects were informed with the detected items and agreed to participate in the study. METHODS: All the 9 patients with ischemic stroke at acute period and 9 healthy subjects were examined with MRI, T1 weighted imaging, T2 weighted imaging and DTI. And the data were processed offline with dTV.II software, the images of fractional anisotropy and directional encoded color (DEC) were obtained, and the three-dimensional fibrous band images of bilateral corticospinal tracts were reconstructed. In the control group, the values of fractional anisotropy of main white matter fibrous bands were measured in the region of interest (ROI) of the anterior limb, knee and posterior limb of internal capsule. In the patient group, the values of fractional anisotropy of white matter were measured in the infarcted sites and corresponding contralateral sites of the patients. The ROI was set in bilateral cerebral peduncles to reconstruct three-dimensionally the bilateral corticospinal tracts. The muscle strength of the affected hand was assessed with Brunnstorm standard in the stroke patients. MAIN OUTCOME MEASURES: The characters of DTI and images of the value of fractional anisotropy, and the manifestations of three-dimensional corticospinal tracts were observed in the two groups. RESULTS: All the data from the 9 patients and 9 healthy volunteers were involved in the analysis of results. ① In the control group, the white matter and gray matter could be distinguished clearly in the image of fractional anisotropic values, the fibers of different directions were shown by different colors in DEC picture, which clearly demonstrated the normal anatomic structure and direction of white matter fibers. In the patient group, the infarctions occurred in the gray matter or white matter could be distinguished in the images of fractional anisotropic values, DEC picture could clearly show the direct influence of the infarcted site on the white matter fibers. The fractional anisotropic values in different white matter structure of the same side were significantly different in the control group (t=3.12, P < 0.05), and the reconstructed images fractional anisotropic values and DEC picture could show most of the main white matter fibrous bands. The fractional anisotropic values of the infarcted sites were significantly lower than the contralateral ones in the patient group (t=5.570, P < 0.01). ② The reconstructed bilateral corticospinal tracts showed that the anatomic forms of the contralateral corticospinal tract of the patients were almost identical to those of normal people, it started from precentral gyrus, downward to the nternal capsule, and extended to pontine and medulla oblongata, each fibrous band was continuous, and the form had good consistency. Because of the involvement of infarction of different severity, the ipsilateral corticospinal tract manifested as continuous interruption and the loss of consistent anatomic structural form. The involved severity of corticospinal tract had significant correlation with that of muscle strength of the ipsilateral hand (r=1.30, P < 0.01). CONCLUSION: ① DTI can display the direction and distribution of cerebral white matter fibrous bands. ② DTI images of fractional anisotropic values and DEC can show the directions and anisotropic degree of white matter fibers in the infarcted sites of stroke patients. ③ The three-dimensional images of fibrous bands can show the conditions of pyramidal tracts more directly. ④ The damaged severity of corticospinal tracts is correlated with that of muscle strength.
基金the National Natural Science Foundation of China, No. 90307013the Natural Science Foundation for Universities in Jiangsu Province, No. 05KJB180105a grant from Social Development Fund of Nantong City, No. S40052
文摘BACKGROUND: There are many methods for myelin staining,mordant,or the special reaction of osmic acid with lipoid is used according to different principles.The commonly used methods are classic Well staining ,classic lithium carbonate-haematine staining,fast green staining,silver staining ,etc.Luxol Fast Blue can brightly stain myelin sheath,and has certain specificity .The background can be very clean if there is proper differentiation,whereas Luxol Fast Blue is cheap and convenient to operate,thus it is an ideal staining reagent for routine myelin sheath.OBJECTIVE: To show the coricospinal tract of normal adult rats with Luxol Fast Blue shaining method.DESIGN:A repetitive measurement design.SETTINGS: Institute of Nuerobiology,Nantong University;Department of Rehabilitation Medicine,Affiliated Hospital of Nantong University.MATERIALS: Six healthy adult male SD rats of clean dergree,weighing averagely 300 g.were provided by the experimental animal center of Nantong University.1 g/L Luxol Fast Blue solution was provided by Sigma Company;Leica CM1900 cryostat microtome by Leica Company;Leica DMR microscope by Leica Company.METHODS:The experiment was carried out in the Staff Room of Human Anatomy,Nantong University in May 2005.The rats were given intraperitoneal injection of combined anesthetic(2 mL/kg),then the chest was open for perfusing saline and phosphate buffer containing formamint via heart. Brain and spinal cord were removed after 1 hour then fixed,then changed to phosphate buffer(pH 7.4)containing 300 g/L saccharu at 4 ℃.and stayed overnight,tissue blocks at pyramid,decussation of pyramid and cervical,thoracic,lumbar and sacral segments of spinal cord were removed to prepare continuous horizontal frozen sections(30 μm) after sedimentation,the sections were dried at room temperature.The corticospinal tract of normal adult rats were shown with Luxol Fast Blue staining method,and observed under Leica DMR microscope.MAIN OUTCOME MEASURES:Positive fibers in Luxol Fast Blue staining.RESULTS:After the Luxol Fast Blue staining,the labeled myelinated nerve fibers were bright blue.They located in the pyramid,decussation of pyramid and the ventral part of posterior funiculus in cervical,thoracic,lumbar and sacral segments of spinal cord.CONCLUSION:Luxol Fast Blue staining method may manifest the distribution of corticospinal tract with clear distinct in adult rats.
文摘Application of continuous repetition of motor imagery can improve the performance of exercise tasks.However,there is a lack of more detailed neurophysiological evidence to support the formulation of clear standards for interventions using motor imagery.Moreover,identification of motor imagery intervention time is necessary because it exhibits possible central fatigue.Therefore,the purpose of this study was to elucidate the development of fatigue during continuous repetition of motor imagery through objective and subjective evaluation.The study involved two experiments.In experiment 1,14 healthy young volunteers were required to imagine grasping and lifting a 1.5-L plastic bottle using the whole hand.Each participant performed the motor imagery task 100 times under each condition with 48 hours interval between two conditions:500 mL or 1500 mL of water in the bottle during the demonstration phase.Mental fatigue and a decrease in pinch power appeared under the 1500-mL condition.There were changes in concentration ability or corticospinal excitability,as assessed by motor evoked potentials,between each set with continuous repetition of motor imagery also under the 1500-mL condition.Therefore,in experiment 2,12 healthy volunteers were required to perform the motor imagery task 200 times under the 1500-mL condition.Both concentration ability and corticospinal excitability decreased.This is the first study to show that continuous repetition of motor imagery can decrease corticospinal excitability in addition to producing mental fatigue.This study was approved by the Institutional Ethics Committee at the Nagasaki University Graduate School of Biomedical and Health Sciences(approval No.18121302)on January 30,2019.
基金supported by the National Research Foundation(NRF) of Korea Grant funded by the Korean Government(MSIP)(No.2015R1A2A2A01004073)
文摘The corticospinal tract(CST)is a major neural tract for motor function in the human brain.In addition,CST is mainly concerned with execution of movement of the hand(Jang,2014).However,few studies are reported on the mechanism underlying CST recovery after traumatic brain injury(Seo and Jang,2015).In this study,we report on a case that showed recovery of an injured CST by traumatic
文摘BACKGROUND: Three-dimensional diffusion tensor tract (DTT) is the newest imaging to describe the structure of white matter fiber in three-dimensions, it has great significance in dividing the concrete anatomic site of gray and white matter lesions, displaying the correlation with fibrous band and judging clinical prognosis, which is incomparable by other imagings. OBJECTIVE: To observe the conditions of corticospinal tract (CST) in acute cerebral ischemic stroke patients, and analyze the relationship between motor function and the severity of CST injury. DESIGN: A case-control observation. SETTING: Department of Medical Imaging, Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA. PARTICIPANTS: Fifteen patients with acute cerebral infarction were selected from Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA from February to December in 2005. They all suffered from acute attack and motor disorder of hemiplegic limbs to different extent, and were conformed by CT or MRI. There were 9 males and 6 females, aging 16-87 years old, the median age was 51.7 years, and all were right handed. Fifteen right-handed normal subjects, who were matched by age and sex with the patients in the cerebral infarction group, were selected from the relatives of patients and physicians of the Imaging Department as the control group. All the subjects were informed and agreed with the study. METHODS: The patients with acute cerebral infarction and subjects in the control group received MR diffusion tensor imaging (DTI) with GE 1.5 T nuclear magnetic resonance system, fiber tracking with the software of dTV-Ⅱ. Fractional anisotropy (FA) maps and three-dimensional tractography of bilateral CST of all patients were created. Displacement, continuity and destroy of fibrous bands were observed. At the same time, muscle strength of ipsilateral hand of patients with cerebral infarction was measured with Brunnstrom standard. The correlation between the severity of CST injury and the muscle strength of ipsilateral hand was analyzed with spearman correlation analysis. MAIN OUTCOME MEASURES: ① FA values in the infarcted sites and those in the contralateral corresponding sites of patients with cerebral infarction; ② CST manifestations in the patients with cerebral infarction and the control group. RESULTS: All the 30 testees were involved in the analysis of results. ① The FA values in infarcted sites of white matter were significantly lower than those in the contralateral ones (t =4.570,P < 0.001). ② In the control group, bilateral CST were reconstructed, they originated from precentral gyrus, went downwards to internal capsule, and extended to pontine and medulla oblongata, each fiber had good uniformity in continuous form. In the patients with cerebral infarction, the forms of contralateral CST were consistent with those in the control group with good continuity. Due to the involvement by the infarcted site to different extents, the ipsilateral CST manifested as continuous interruption and loss of uniformity in anatomic structure and form. The CST involvements were divided into three grades: integrated CST for grade 1 (n =2); integrated CST but compressed or displaced for grade 2 (n =5); interrupted CST for grade 3 (n =8). ③ The severity of CST injury was obviously correlated with the muscle strength of the ipsilateral hand (r =0.888, P < 0.05). CONCLUSION: ① CST is injured to different extents in patients with acute cerebral infarction, and the severity of injury is associated with muscle strength. It is indicated that it can be used to judge the prognosis of rehabilitative treatment. ②DTT can directly display the status of pyramidal tract more three-dimensionally.
文摘Objectives: The aim of the study is to assess volumetric Corticospinal Tract infiltration by Astro-cytoma using Diffusion Tensor Tractography. Material and Methods: Preoperative, anatomic (T1- and T2-weighted) and diffusion tensor MRI were performed in 9 patients with supratentorial gliomas (WHO grade II and III). The tumors were manually segmented from the T1- and T2-weighted MRI, and their volume calculated. A three-dimensional tractography was performed in each case. A second segmentation and volume measurement was performed on the tumor regions intersecting adjacent white matter fiber tracts. Results: We identified that white matter tracts were infiltrated by 6 Astrocytoma tumors. The median tumor volume (±standard deviation) in our patient population was 33 ± 26.82 ml. The median tumor volume (±standard deviation) infiltrating white matter fiber tracts was 4.15 ± 9.23 ml. The median fraction of tumor volume infiltrating white matter fiber tracts was 26.3% ± 10.1%. Conclusions: Diffusion tensor MR Tractography is a reliable preoperative assessment tool since it detects extensive white matter infiltration by Astrocytoma irrespective of brain tumors volume. Recommendations: Prospective large population studies are required to clarify how infiltration relates to tumor location.
基金supported by the National Stroke Rehabilitation Research Foundation of the Ministry of Health, China,No.01BA703B18bthe Young and Middle-Aged Clinical Scientists Research Foundation of Shanghai Government,No.01YZK
文摘To investigate the feasibility and time window of early detection of Wallerian degeneration in the corticospinal tract after middle cerebral artery infarction,23 patients were assessed using magnetic resonance diffusion tensor imaging at 3.0T within 14 days after the infarction.The fractional anisotropy values of the affected corticospinal tract began to decrease at 3 days after onset and decreased in all cases at 7 days.The diffusion coefficient remained unchanged.Experimental findings indicate that diffusion tensor imaging can detect the changes associated with Wallerian degeneration of the corticospinal tract as early as 3 days after cerebral infarction.
文摘Although neuroimaging is commonly utilized to study Wallerian degeneration,it cannot display Wallerian degeneration early after brain injury.In the present study,we attempted to examine pathologically the process of Wallerian degeneration early after brain injury.Cerebral peduncle demyelination was observed at 3 weeks post brain ischemia,followed by demyelination in the cervical enlargement at 6 weeks.Anterograde tracing of the corticospinal tract with biotinylated dextran amine showed that following serious neurologic deficit,the tracing of the corticospinal tract of the internal capsule,cerebral peduncle,and cervical enlargement indicated serious Wallerian degeneration.
基金supported by the Yeungnam University Research Grants in 2010
文摘The corticospinal tract(CST) is one of the most important neural tracts for motor function in the human brain.Little is known about age-related changes of the CST.In this study,we tried to evaluate age-related changes of the CST using diffusion tensor imaging in 60 healthy subjects.The diffusion tensor imaging result revealed that the tract number and fractional anisotropy value were decreased,and the apparent diffusion coefficient(ADC) value was increased with aging.The distribution showed a semilog pattern for tract number,fractional anisotropy and ADC of the CST,and the pattern of each graph was near-linear.When compared with the diffusion tensor imaging parameters of subjects in the 20 s age group,tract number and fractional anisotropy values were significantly decreased in the 50 s-70 s age groups.Likewise,the ADC value was significantly higher in the 50 s-70 s age groups.The CST in the brain of normal subjects degenerated continuously from the 20 s to the 70 s,with a near-linear pattern,and degeneration of the CST began to manifest significantly in the subjects in their 50 s,compared with the subjects in their 20 s.
基金the National Natural Science Foundation of China, No. 30801470
文摘The present study investigated the effects of Fujian tablet, a Chinese medicine compound that can nourish liver and kidney, on corticospinal tract plasticity and cervical cord microenvironment in rats with focal cerebral ischemia. Results showed that motor function of rats with right proximal middle cerebral artery occlusion was significantly improved following treatment with Fujian tablet, 9 g crude drug/kg. Anterograde tracing revealed significantly increased biotinylated dextran amine expression in the denervated (left) side of the cervical cord (C4-6) following Fujian tablet treatment, and significantly decreased Nogo-A mRNA expression was detected in the denervated side of the cervical cord (C4-6) using in situ hybridization. Pearson's correlation analysis showed a negative correlation between biotinylated dextran amine and Nogo-A mRNA expression (r = -0.943, P < 0.01). Results demonstrated that Fujian tablet can promote corticospinal tract plasticity possibly through the inhibitory effect on Nogo-A mRNA expression in the cervical spinal cord, thereby improving motor dysfunction.
基金Fsupported by the Priority Academic Development Program of Jiangsu Higher Education Institutions
文摘In this study, biotinylated dextran amine (BDA) was microinjected into the left cortical motor area of the canine brain. Fluorescence microscopy results showed that a large amount of BDA-labeled pyramidal cells were visible in the left cortical motor area after injection. In the left medulla oblongata, the BDA-labeled corticospinal tract was evenly distributed, with green fluorescence that had a clear boundary with the surrounding tissue. The BDA-positive corticospinal tract entered into the right lateral funiculus of the spinal cord and descended into the posterior part of the right lateral funiculus, close to the posterior horn, from cervical to sacral segments. There was a small amount of green fluorescence in the sacral segment. The distribution of BDA labeling in the canine central nervous system was consistent with the course of the corticospinal tract. Fluorescence labeling for BDA gradually diminished with time after injection. Our findings indicate that the BDA anterograde tracing technique can be used to visualize the localization and trajectory of the corticospinal tract in the canine central nervous system.
基金the National Research Foundation of Korea Grant funded by the Korean Government, No. KRF-2008-314-E00173
文摘Subdural hematoma can cause compression or damage to the neural tracts in the brain; however, very little is known about this injury. We report on a patient with subdural hematoma who was evaluated by diffusion tensor imaging prior to and after trephination and drainage of subdural hematoma. A 58-year-old male patient and ten age-matched normal control subjects were evaluated. The patient showed mild hemiparesis for 3 weeks prior to surgery. His hemiparesis recovered to a nearly normal state at 5 weeks post-surgery when the follow up diffusion tensor image was acquired. Two diffusion tensor image parameters, fractional anisotropy and apparent diffusion coefficient, were measured along the corticospinal tract. Pre-operative diffusion tensor image showed that the corticospinal tract of the affected hemisphere seemed to be injured or compressed. However, the follow up diffusion tensor image showed recovery of this corticospinal tract to a normal state. It would appear that diffusion tensor images are a useful tool for evaluation of the effects of subdural hematomas on neural tracts.
基金supported by Daegu Innopolis R&BD Project by the Korea Institute for Advancement of Technology
文摘Many studies have attempted to elucidate the motor recovery mechanism of stroke,but the majority of these studies focus on cerebral infarct and relatively little is known about the motor recovery mechanism of intracerebral hemorrhage.In this study,we report on a patient with intracerebral hemorrhage who displayed a change in injured corticospinal tract originating from the premotor cortex to the primary motor cortex on diffusion tensor imaging.An 86-year-old woman presented with complete paralysis of the right extremities following spontaneous intracerebral hemorrhage in the left frontoparietal cortex.The patient showed motor recovery,to the extent of being able to extend affected fingers against gravity and to walk independently on even ground at 5 months after onset.Diffusion tensor imaging showed that the left corticospinal tract originated from the premotor cortex at 1 month after intracerebral hemorrhage and from the left primary motor cortex and premotor cortex at 5 months after intracerebral hemorrhage.The change of injured corticospinal tract originating from the premotor cortex to the primary motor cortex suggests motor recovery of intracerebral hemorrhage.
基金supported by the National Natural Science Foundation of China,No.30972153
文摘Following central nervous system injury, axonal sprouts form distal to the injury site and extend into the denervated area, reconstructing neural circuits through neural plasticity. How to facilitate this plasticity has become the key to the success of central nervous system repair. It remains controversial whether fine motor skill training contributes to the recovery of neurological function after spinal cord injury. Therefore, we established a rat model of unilateral corticospinal tract injury using a pyramidal tract cutting method. Horizontal ladder crawling and food ball grasping training procedures were conducted 2 weeks before injury and 3 days after injury. The neurological function of rat forelimbs was assessed at 1, 2, 3, 4, and 6 weeks after injury. Axon growth was observed with biotinylated dextran amine anterograde tracing in the healthy corticospinal tract of the denervated area at different time periods. Our results demonstrate that compared with untrained rats, functional recovery was better in the forelimbs and forepaws of trained rats. The number of axons and the expression of growth associated protein 43 were increased at the injury site 3 weeks after corticospinal tract injury. These findings confirm that fine motor skill training promotes central nervous system plasticity in spinal cord injury rats.
基金the National Research Foundation of Korea Grant Funded by the Korean Government, No. KRF-2008-314-E00173
文摘Integrity of the corticospinal tract is mandatory for good recovery of impaired motor function in patients who have suffered a stroke. A 67-year-old left hemiparetic female showed an infarct in the right pons. Three months after onset, motor function of the affected extremities recovered rapidly to a nearly complete state. Diffusion tensor tractography of both hemispheres showed that the corticospinal tract originated from the primary sensori-motor cortex and descended through the known corticospinal tract pathway. The tract of the affected (right) hemisphere descended through an area within the pontine infarct. The diffusion tensor tractography results suggest that from the onset, the integrity of the corticospinal tract appears to have been spared within the pontine infarct.
基金a grant from Daegu Metropolitan City R&D Project
文摘The present study reported a 42-year-old male patient who underwent conservative management for a spontaneous intracerebral hemorrhage in the left corona radiata and the basal ganglia.The patient presented with complete weakness of the right upper and lower extremities at the onset of intracerebral hemorrhage;however,he showed progressive motor recovery to the level that he was able to extent the affected extremities against some resistance at 5 weeks after onset.The corticospinal tract of the affected (left) hemisphere connected to the left Broca's area at 3 weeks after onset as shown by diffusion tensor tractography.By contrast,this connection had disappeared at 5 weeks after onset as shown by diffusion tensor tractogaphy.Transcranial magnetic stimulation study showed that no motor evoked potential was elicited from the affected (left) hemisphere at 3 weeks after onset,but motor evoked potentials were elicited at 5 weeks after onset.These findings suggest that the connection between the injured corticospinal tract and Broca's area in this patient appears to be a compensation for severe motor weakness;consequently,the connection seems to disappear with motor recovery.
