Fractional anisotropy (FA) and mean diffusivity (MD) were calculated for six fiber tracts (uncinate fasciculus [ UF], arcuate fasciculus [ AF], fornix [ FORX], parahippocampal cingulum [ PHC], inferior fronto-occipital fasciculus [ IFOF], and corticospinal tract [ CST]). 
Diffusion tensor imaging (DTI) and transcranial magnetic stimulation (TMS) could be useful for exploring the state of the corticospinal tract (CST).
A more effective activation of these neurones by not only ipsilateral corticospinal and reticulospinal but also rubrospinal tract neurones may thus contribute to the recovery of motor functions after injuries of the contralateral corticospinal tract neurones.
In a spinal cord dorsal hemisection model, NgR immunization promoted regeneration of lesioned corticospinal tract (CST) axons, anterogradely labeled with biotin dextran amine (BDA), beyond the lesion site.
However, single-pulse BST (single BST) sometimes cannot elicit motor evoked potentials (MEPs) in patients with corticospinal tract involvement. Subjects were 11 healthy volunteers and 12 patients with corticospinal tract involvement in whom single BST evoked no discernible MEP.
This recovery was accompanied by increased numbers of regenerated axons in the corticospinal tract and neurofilament-positive fibers around the lesion site.
The voxel-based comparison between control and patient groups identified abnormalities in the ipsilesional corticospinal tract and contralesional cerebellar peduncles.
Using a tract-based atlasing approach on six-direction diffusion tensor imaging data, we examined FA within the cingulum, corpus callosum, corticospinal tract, fornix, optic radiations, superior longitudinal fasciculus, uncinate fasciculus, and the superior and inferior occipitofrontal fasciculi in an all-male sample of 17 children and adolescents with ADHD and 16 age-matched controls. ADHD patients had significantly lower FA in the corticospinal tract (P=0.02) and the superior longitudinal fasciculus (P=0.017) compared with controls.
OBJECTIVE: For quick and stable identification of the primary motor area (PMA), diffusion tensor imaging (DTI) data were acquired and corticospinal tractography was mathematically visualized. Off-line processing of DTI data was performed to visualize the corticospinal tract, placing a seed area in the cerebral peduncle of the midbrain, where the corticospinal tract is densely concentrated. Somatosensory evoked magnetic fields and intraoperative cortical somatosensory evoked potentials were recorded with electrical stimulation of the median nerve to confirm the results of the corticospinal tractography. Using the appropriate seed area and fractional anisotropy, corticospinal tractography successfully indicated the PMA location in all patients. CONCLUSION: corticospinal tractography enables identification of the PMA and is beneficial, particularly for patients who present with dysfunction of the PMA..
We used magnetic resonance diffusion tensor imaging and diffusion tensor tractography to investigate the effects of benign extracerebral lesions on the corticospinal tract (CST).
The corticospinal tract provides the most direct pathway over which the cerebral cortex controls movement. Based on this phylogenetic trend, humans are believed to have more direct corticomotoneuronal synapses than any other species, consistent with observations that humans suffer more extensive loss of motility from lesions of the corticospinal tract than do other mammals. Animal studies have shown that although the bulk of the corticospinal tract arises from the primary motor cortex, this projection is not the only route via which the brain controls movement. Adjacent areas in the frontal and parietal lobes also contribute axons to the corticospinal tract, as well as having corticocortical connections with the motor cortex.
A non-myelinated component of the corticospinal tract, including axonal varicosities and synaptic contacts, was observed in the dorsal part of the white matter of the lumbar enlargement of the spinal cord..
In this study, we investigate whether rehabilitative training of the forelimb (forced limb use) influences behavioral recovery and plastic events after injury to a defined spinal tract, the corticospinal tract (CST).
sparing the corticospinal tract (CST), or involved both the ASP and the CST (DLF+DF group).
BACKGROUND AND PURPOSE: There are 2 main hypotheses concerning the cause of mirror movements (MM) in Kallmann syndrome (KS): abnormal development of the primary motor system, involving the ipsilateral corticospinal tract; and lack of contralateral motor cortex inhibitory mechanisms, mainly through the corpus callosum. Regarding white matter alterations, no areas of altered volume involving the corpus callosum or the projection of the corticospinal tract were demonstrated.
The clusters were located primarily in bilateral frontal and temporal lobes and were localized within white matter tracts, including portions of the inferior and superior longitudinal fasciculi, anterior thalamic radiation, uncinate fasciculus, inferior fronto-occipital fasciculus, corticospinal tract, and splenium of the corpus callosum.
The corticobulbar tract fibers descend near the corticospinal tract, mostly to the upper medulla, where they decussate and ascend in the dorsolateral medulla to connect with the contralateral facial nucleus.
RESULTS: Simultaneous use of CUSA and DES at the subcortical level in proximity to the corticospinal tract brought about the abolition of previously evident motor responses.
BACKGROUND: The development of the corticospinal tract (CST) in higher vertebrates relies on a series of axon guidance decisions along its long projection pathway.
Cervical spinal cord injury (SCI) can severely impair reaching and grasping ability, and several descending systems, including the rubrospinal tract and corticospinal tract, have been implicated in the control of reach-to-grasp movements. The primary aim of this study was to characterize further the forelimb deficits associated with a cervical dorsolateral funiculotomy, which ablates the rubrospinal tract but spares the dorsal and ventral corticospinal tract in the rat.
Wnt1 and Wnt5a, encoding potent repellents of the descending corticospinal tract (CST) axons, were robustly and acutely induced broadly in the spinal cord gray matter after unilateral hemisection.
There is limited data on the relation of corticospinal tract conductivity to clinical measures in incomplete spinal cord injury. This study examined the relationship of muscle strength to corticospinal tract input assessed by motor evoked potentials (MEPs) during static and dynamic conditions and to gait. In incomplete spinal cord injury patients, the dynamic measure maximal movement velocity might be a useful clinical assessment of corticospinal tract function. Clinical studies on recovery and repair of corticospinal tract function in spinal lesions could substantially benefit from implementing dynamic measures in the clinical assessment protocol..
We investigated whether the integrity of the corticospinal tract classified by diffusion tensor tractography (DTT) can predict the motor outcome in 25 patients with pontine infarct. DTTs were obtained in the early stage of stroke (5-30 days) and were classified into two groups (type A: the integrity of corticospinal tract was preserved around the infarct; type B: corticospinal tract was interrupted).
The aim of this work was to study the diffusion-related signal attenuation curves (signal-vs.-b curves) measured perpendicular and parallel to the neuronal fibers of the corticospinal tract in vivo and to determine whether effects of restricted diffusion could be observed when varying the diffusion time (T(D)).
This may lead to the inability to visualize clinically important tracts such as the lateral projections of the corticospinal tract. By tracing the corticospinal tract and correlating with fMRI-determined motor cortex in both healthy subjects and patients with brain tumors, we demonstrate that two-tensor deterministic streamline tractography can accurately identify fiber bundles consistent with anatomy and previously not detected by conventional single-tensor tractography.
MEASUREMENTS AND RESULTS: Multiple regions of lower FA appeared within white matter in the OSA group, and included fibers of the anterior corpus callosum, anterior and posterior cingulate cortex and cingulum bundle, right column of the fornix, portions of the frontal, ventral prefrontal, parietal and insular cortices, bilateral internal capsule, left cerebral peduncle, middle cerebellar peduncle and corticospinal tract, and deep cerebellar nuclei.
The corticospinal tract and the corpus callosum were studied as 'control' white matter (WM).
Small fusiform and larger lentiform neurons are most abundant in the gracile fasciculus of the cervical and lumbar enlargements and are absent from the cuneate fasciculus and corticospinal tract.
Motor development depends on forming specific connections between the corticospinal tract (CST) and the spinal cord.
We prospectively investigated pathological modifications in the corticospinal tract (CST), by diffusion tensor imaging (DTI) in 14 patients with sporadic amyotrophic lateral sclerosis (ALS) and 12 healthy volunteers.
The patient had sustained direct injury to the corticospinal tract and limbic system during revision of a ventriculoperitoneal shunt at the age of 9 years. RESULTS: Despite persistent evidence of severe disruption of the corticospinal tract on diffusion tensor imaging at age 14 years, the patient had regained complete motor function.
We investigated contralesional corticospinal tract remodeling in the brain and spinal cord in rats after stroke and treatment of bone marrow stromal cells. When intracortical microstimulation was completed, biotinylated dextran amine was injected into the left motor cortex to anterogradely label the corticospinal tract. RESULTS: In normal rats (n=5), the corticospinal tract showed a unilateral innervation pattern. CONCLUSIONS: Our data demonstrated that corticospinal tract fibers originating from the contralesional motor cortex sprout into the denervated spinal cord after stroke and bone marrow stromal cells treatment, which may contribute to functional recovery..
BACKGROUND: Mutations in SPG4 cause the most common form of autosomal dominant hereditary spastic paraplegia, a neurodegenerative disease characterized by weakness and spasticity of the lower limbs due to degeneration of the corticospinal tract.
The Global ALS/MND phenotype can present with initial symptoms in any region and rapidly progresses to involve all segments, with symptoms due to a mixture of combined corticospinal tract and anterior horn cell dysfunction.
Morphological analysis of injured axons in the dorsal corticospinal tract showed an increase in the radius and perimeter of stained axons, which were reduced by FK1706 treatment, suggesting that axonal swelling and retraction balls observed in injured spinal cord were improved by the neurotrophic effect of FK1706.
At interstimulus intervals where MEP facilitation was observed (near 50 ms), spinal H-reflexes and responses evoked from corticospinal tract stimulation at the brainstem were predominantly depressed by the sensory stimulus suggesting that the observed MEP facilitation was cortical in origin.
Studies that have assessed regeneration of corticospinal tract (CST) axons in mice after genetic modifications or other treatments have tacitly assumed that there is little if any regeneration of CST axons in normal mice in the absence of some intervention.
At autopsy both the mother and her daughter had pathologic findings of Alzheimer disease, and histologic evidence of corticospinal tract degeneration.
Average values of myelin water fraction (MWF), fractional anisotropy (FA), longitudinal diffusivity (D(long)), transverse diffusivity (D(trans)), and average diffusivity (D(ave)) were calculated in the fasciculus gracilis, fasciculus cuneatus, and the dorsal corticospinal tract (CST) 5 mm cranial, as well as 5 and 10 mm caudal to injury and correlated with histology.
Fracture-dislocations produced greater axonal degeneration than either contusion or distraction injuries as evidenced by reduced neurofilament immunostaining in ventral tracts, increased beta-amyloid precursor protein accumulation in lateral funiculi, and a longer lesion in the dorsal corticospinal tract.
The grafts were put in the corticospinal tract of the cord randomly, without possibility of choosing the axons coming from different areas of the brain cortex.
This review explores to what extent descending pathways are highly conserved across species and concludes that there are actually rather widespread species differences, for example, in the transmission of information from the corticospinal tract to upper limb motoneurons.
The mutant hyt/hyt mouse, characterized by fetal-onset, life-long hypothyroidism resulting from a point mutation of the thyroid-stimulating hormone receptor of the thyroid gland, displays a variety of abnormalities in motor behavior that are likely associated with dysfunctions of specific brain regions and a defective corticospinal tract (CST).
The diffusion tensor tractography (DTT) allows the corticospinal tract(CST) to be visualized at the subcortical level and functional MRI (fMRI) is capable of precisely identifying activation sites at the cortex. The tract of the affected hemisphere originated from the lateral area of the injured precentral knob and descended along the known corticospinal tract pathway.
One of the most striking examples of stereotyped pruning in the CNS is the pruning of corticospinal tract (CST) axons.
We demonstrated the recovery of a severely damaged corticospinal tract (CST) in a 45-year-old female patient with intracerebral hemorrhage using diffusion tensor tractography and transcranial magnetic stimulation.
Analysis of damaged, immunoreactive axonal profiles revealed significant axonal protection in the PACAP-treated versus vehicle-treated animals in the corticospinal tract, as far as traumatically induced disturbance of axoplasmic transport and cytoskeletal alteration were considered.
The aim of this study is to evaluate the anisotropic changes of cerebral white matter tracks in patients with ischemic stroke using DTI, and investigate the correlation between corticospinal tract damage and muscle strength in such patients during acute ischemia. Fractional anisotropy (FA) was measured and the three-dimensional fibrous band images of bilateral corticospinal tracts were reconstructed. RESULTS: In the control group, there was no significant difference in FA between the bilateral corticospinal tracts, but FA in different white matter structures of the same side was significantly different (t=3.12, p<0.05); while in the patient group, FA of the infarcted sites was significantly lower than the contralateral ones (t=5.570, p<0.01). The ipsilateral corticospinal tract demonstrated continuous interruption and the loss of consistent anatomic structure. The involved severity of corticospinal tract had significant correlation with that of muscle strength of the ipsilateral hand (r=1.30, p<0.01). The damaged severity of corticospinal tracts is correlated with that of muscle strength..
However, because EMG responses to direct activation of the corticospinal tract were significantly less affected than the responses to F5 stimulation, it is unlikely that reduced motoneuronal excitability explained the loss of the evoked responses from F5.
Therefore, the effects of MSA are apparently related to selective loss of the small-sized myelinated fibers in the corticospinal tract..
Transcranial magnetic stimulation allows to study the properties of the human corticospinal tract non-invasively.
We attempted to elucidate the corticospinal tract location at the posterior limb of the internal capsule in the human brain. Probabilistic mapping was performed using the functional MRI activation resulting from a hand motor task as region of interest 1 and the corticospinal tract area of the anterior pons as region of interest 2. The average location of the highest density point of the corticospinal tract was mid-posterior portion with the standard from the most medial point to the most posterior point of the lenticular nucleus. In conclusion, we demonstrated that the corticospinal tract for the hand descended through the posterior portion of the posterior limb at the mid-thalamic level..
In the thoracic spinal cord, degenarated anterior horn cells were seen and macrophage permeation in the corticospinal tract were shown by CD68 immunostaining.
METHODS: Diffusion tensor MRI measurements were obtained from tractography for uncinate, arcuate, inferior longitudinal fasciculi and corticospinal tract in 13 children with left temporal lobe epilepsy and normal conventional MRI, and the data were compared to measurements in 12 age-matched normal volunteers.
The present study shows that an injection of DiI into the motor cortex of the young adult jimpy mutant mice (Plp1(jp)/+) resulted in successful anterograde labeling of corticospinal tract fibers. Furthermore, an injection of Fast Blue into the lumbar spinal cord of the mutant mice resulted in retrograde labeling of layer 5 corticospinal tract neurons within the motor cortex.
Cord lesion number, cross-sectional area, mean diffusivity (MD) and fractional anisotropy (FA), whole brain and left corticospinal tract lesion volume (LV), gray matter (GM) MD, and normal-appearing white matter (NAWM) MD and FA were calculated. Cord average signal change correlated significantly with cord FA and brain left corticospinal tract LV, GM-MD, and NAWM-FA.
This study assessed changes in corticospinal tract (CST) function by measuring motor-evoked potentials (MEPs) and ankle motor control at 1, 3, and 6 months after acute iSCI.
Histological analysis showed axons of the corticospinal tract exhibited significant regeneration past the injury site, when quantified both by number and length.
To our knowledge, this study is the first attempt to demonstrate relationship between MRI abnormalities and MR spectroscopic metabolite changes of the motor cortex, frontal white matter and corticospinal tract in a patient with the diagnosis of ALS with probable upper motor neuron signs (ALS-PUMNS) and FTD. Spectra from the right motor cortex, frontal white matter and corticospinal tract were obtained. MR images were evaluated for sulcus centralis enlargement, corticospinal tract hyperintensity and frontal lobes atrophy. MR images revealed sulcus centralis enlargement, high signal intensity of corticospinal tract and atrophy of both frontal lobes.
The great repertoire of movements in higher order mammals comes courtesy of the corticospinal tract (CST) which is able to initiate precise movement of the entire musculature of the axial and limb muscle groups.
After hemisection, many anterogradely labeled corticospinal tract (CST) axons remained close to CSPG-rich lesion sites, but after contusion, most CST axons retracted by approximately 1 mm rostral from the rostral-most CSPG-rich cyst.
We report a high-voltage electrical injury to the cerebral corticospinal tracts and document evolution on serial MR images..
We provide examples of the use of DTI in the study of the corpus callosum, the anterior white commissure, the corticospinal tract, the limbic system, the long association fibers, the cerebellar peduncles, and the optic tract..
The aims of this study are to investigate whether the integrity of corpus callosum (CC), cingulum, uncinate fasciculus (UF), optic radiation (OR) and corticospinal tract (CST) are damaged in patients with MR, and to determine the correlations between the integrity of these tracts and full scale intelligence quotient (FSIQ) in both patients and controls.
RESULTS: Preterm male subjects demonstrated significantly lower white matter volumes in bilateral cingulum, corpus callosum, corticospinal tract, prefrontal cortex, superior and inferior longitudinal fasciculi compared with term male subjects.
After injury to the corticospinal tract, NgR1 limits axon collateral sprouting but is not important for blocking long-distance regenerative growth in vivo.
We quantified fractional anisotropy (FA) and mean diffusivity (MD) to demonstrate retrograde Wallerian degeneration (WD) of cranial corticospinal tract (CST) in cervical spinal cord injury (SCI).
This paper contrasts responses in the soleus muscle of normal human subjects to two major inputs: the tibial nerve (TN) and the corticospinal tract.
Hemiplegia and supranuclear facial nerve palsy were considered to be caused by the involvement of corticospinal tract and corticobulbar tract that run at the ventromedial area of the pons.
Magnetic resonance imaging showed asymmetric cortical atrophy and unusual corticospinal tract hyperintensity in T2-weighted images. corticospinal tract degeneration is an exceptional finding..
The motor tracts of the affected hemisphere were observed to pass along the same spared peri-infarct corticospinal tract area of the pons on both the first and second diffusion tensor tractography. It seems that the main motor function of these patients is controlled via the spared peri-infarct corticospinal tract..
It can be explained by (1) the lateral lenticulostriate artery (LSA), which supplies the posterolateral striatum vulnerable to ischemic damage due to the lack of collateral vessels, and (2) the posterolateral division of the striatum may be susceptible to progressive motor deficit because of anatomic proximity to the corticospinal tract in the same LSA territory. Further research should include precise anatomical and functional study to determine the relationship between the posterolateral striatum and corticospinal tract in predicting progressive motor deficit..
OBJECTIVE: To utilize diffusion tensor tractography and evaluate the integrity of the corticospinal tract in children with unilateral Sturge-Weber syndrome (SWS). Diffusion tensor imaging (DTI) was obtained and fiber tracking of the corticospinal tract was performed yielding average FA and ADC values along the pathway. RESULTS: corticospinal tract FA values on the side of the affected hemisphere were lower (p=0.008) and ADC values were higher (p=0.011) compared to the normal side. CONCLUSION: MRI with DTI shows abnormalities of the corticospinal tract in children with SWS even before severe motor impairment develops. Thus, DTI can be a clinically useful method to evaluate the integrity of the corticospinal tract in young children who are at risk for progressive motor dysfunction..
Axons in the descending dorsal corticospinal tract were unaffected in all groups, suggesting a specificity of this lesion for spinal primary sensory afferents.
Neuron 33, 219-232), with ectopic crossing points, and some axons projecting caudally toward the corticospinal tract.
OBJECTIVE: To assess corticospinal tract involvement in patients with amyotrophic lateral sclerosis (ALS) by correlating diffusion tensor imaging (DTI) measures with intra- and extracranial central motor conduction time (CMCT) and clinical features of the patients. METHODS: We investigated 31 patients with ALS and 31 normal volunteers by DTI and measured fractional anisotropy (FA) within the corticospinal tracts and in the extramotor white matter. RESULTS: We found a significant decrease of mean FA in all regions of the corticospinal tracts in patients with ALS as compared with controls. We found that FA along the corticospinal tract decreased significantly with higher UMN scores. CONCLUSIONS: Fractional anisotropy reflects functional abnormality of intracranial corticospinal tracts and can be used for objective evaluation of upper motor neuron impairment in amyotrophic lateral sclerosis..
UL1 neurons in Satb2 mutants fail to migrate to superficial layers and do not contribute to the corpus callosum but to the corticospinal tract, which is normally populated by DL axons. Ctip2, a gene required for the formation of the corticospinal tract, is ectopically expressed in all UL1 neurons in the absence of Satb2.
In mutant mice, beta-galactosidase-labeled axons are absent from the corpus callosum and instead descend along the corticospinal tract.
Here we review some of the impairments in motor control, motor learning and higher-order motor control in patients with lesions of the corticospinal tract, the cerebellum, parietal cortex, the basal ganglia, and the medial temporal lobe.
In this study we investigated the influence of the corticospinal tract on this spinal inhibitory reflex.
Furthermore, L-DOPA-induced PAG608 expression on motor neurons in the contralateral side of the ventral horn of the spinal cord and the lateral corticospinal tract without cell loss.
These can be examined with transcranial magnetic stimulation (TMS) using measures of corticospinal tract integrity and intracortical excitability.
Here we have examined whether corticospinal tract activation modulates the size of monosynaptic focal synaptic potentials (FSPs) evoked by group II muscle afferents, and the excitability of intraspinal terminals of group II afferents, both of which are indices used to show presynaptic control. corticospinal tract conditioning stimuli did not consistently enhance or reduce the depression of group II FSPs that was evoked by stimulation of ipsilateral segmental group II or cutaneous afferents; in the large majority of cases there was no effect.
Intrathecal administration of noggin - a soluble BMP antagonist-leads to enhanced locomotor activity and reveals significant regrowth of the corticospinal tract after spinal cord contusion.
The movement disorder is attributed to damage to the corticospinal tract, but there is increasing evidence of additional cortical dysfunction associated with PVL. Aim of the present study was to evaluate the integrity of the corticospinal tract and cortical inhibitory function using transcranial magnetic stimulation. The patients' parameters of corticospinal tract function did not differ significantly from those in the control children.
Supratentorial brain parenchymal involvement, as well as brain stem involvement, correlated anatomically with corticospinal tract distribution.
After an unilateral lesion of the corticospinal tract (CST) at the level of the medulla over-expression of Neurotrophin-3 (NT-3) in lumbar spinal cord motoneurons induced axonal sprouting of the intact CST in the acutely injured but not uninjured or chronically injured spinal cord in rats.
Other measures were growth of axonal diameters in the corticospinal tract, which were estimated by using transcranial magnetic stimulation, weight gain, and length. Axonal diameters in the corticospinal tract, length, and weight were also significantly increased.
Fractional anisotropy (FA) color maps were used to localize the corticospinal tracts within the brainstem. Patients with well-circumscribed lesions and weakness had higher mean diffusivity and lower FA in the contralateral corticospinal tract (P < 0.05). Patients with well-circumscribed tumors and a bad outcome had significantly lower transverse eigenvalue measures in the corticospinal tracts compared with those with a more favorable clinical status (P < 0.05). CONCLUSION: In patients with well-circumscribed primary posterior fossa masses, higher mean diffusivity and lower FA in the brainstem corticospinal tract are associated with contralateral motor deficits; lower transverse eigenvalue may be observed with an unfavorable clinical outcome..
We investigated the association between the degree of lesion overlap with the corticospinal tract and walking performance before and after 4-weeks of partial body weight support (PBWS) treadmill training in 18 individuals (ten male, eight female) with a mean age 59 +/- 13 years (mean +/- SD), range 32-74 years, who were ambulant and 6 months from a subcortical ischaemic stroke. Lesion volumes were manually defined on high resolution T1-weighted 3T-MRI scans and a probabilistic map of the corticospinal tract created using diffusion tensor imaging data collected previously in healthy subjects. The percentage overlap between the lesion and the corticospinal tract was calculated for each patient. The extent of lesion overlap with the corticospinal tract was not strongly associated with either walking performance or response to gait retraining, despite the correlation of these parameters with upper limb recovery..
No regenerative fibers from corticospinal tract can be seen in the caudal segment near the injury site using BDA tracing technique.
Nck-deficient mice also show abnormal projections of corticospinal tract axons and defective development of the posterior tract of the anterior commissure.
DTI showed right-sided decrease of fractional anisotropy in the genu of the internal capsule and bilateral increase of overall water diffusivity in the white matter along the corticobulbar/corticospinal tract in 20 spasmodic dysphonia patients compared to 20 healthy subjects. The specificity of these brain abnormalities is confirmed by their localization, limited only to the corticobulbar/corticospinal tract and its main input/output structures.
Mapping of the corticospinal tract, at the level of the cerebral peduncle as well as mapping of the VII, IX-X and XII cranial nerve motor nuclei on the floor of the fourth ventricle, is of great value to identify "safe entry-zones" into the brainstem.
RESULTS: The human study showed that fractional anisotropy (FA) values estimated by the proposed method (FA = 0.67 for the corpus callosum, 0.65 for the corticospinal tract) were significantly higher than that estimated by the standard single-tensor-based method (FA = 0.35), and the estimated FA value showed good agreement with the FA value in the adjacent fiber bundle.
The final pattern of the origin and termination of the corticospinal tract is shaped during development by the balance between projection and withdrawal of axons.
The clinical application of spinal D wave and muscle MEP recordings is critically reviewed (especially in the field of Neurosurgery) and new developments such as mapping of the dorsal columns and the corticospinal tracts are presented. On the other hand, D wave changes--when recordable--have proven to be the strongest predictors of maintained corticospinal tract integrity (and therefore, of motor function/recovery).
A new experimental model of lacunar infarction in the miniature pig was developed to investigate the pathophysiological changes in the corticospinal tract from the acute to chronic phases. Seven additional miniature pigs underwent transient anterior choroidal artery occlusion to study muscle motor-evoked potentials and evaluate corticospinal tract function during transient anterior choroidal artery occlusion.
We recorded motor-evoked potentials in the biceps brachii and triceps brachii muscles in response to magnetic stimulation of the motor cortex (MEP) and corticospinal tract (cervicomedullary motor-evoked potentials--CMEPs), as well as the Hoffmann reflex (H-reflex) and maximal M-wave (Mmax) elicited by electrical stimulation of the brachial plexus, before, during, and after the fatigue task.
We tried to demonstrate the restoration of corticospinal tract in a patient with intracerebral hemorrhage, using diffusion tensor tractography and functional magnetic resonance imaging, and transcranial magnetic stimulation. Transcranial magnetic stimulation demonstrated the corticospinal tract had been spared since subacute stage. Diffusion tensor tractography and functional magnetic resonance imaging showed that the corticospinal tract that was displaced by a hematoma had been restored. These combined modalities would be helpful in elucidating the state and change of corticospinal tract..
corticospinal tract findings were present in seven participants.
The dorsal funiculus, consisting of ascending sensory fibers and the main component of the corticospinal tract, was transected either at spinal level C2 or at T8.
Tracing of the corticospinal tract and ascending dorsal column pathway revealed no regeneration of the axons beyond the lesion site.
PURPOSE: To prospectively evaluate diffusion indexes of the corticospinal tract (CST), corpus callosum (CC), optic radiation (OR), and cingulum in patients with neuromyelitis optica (NMO) without visible lesions in the brain.
OBJECTIVES: Precision grasping critically relies on the integrity of the corticospinal tract as evidenced in congenital hemiplegia by the correlation found between corticospinal dysgenesis and hand-movement deficits. METHODS: To address this issue, we measured corticospinal tract areas in 12 patients with congenital hemiplegia and 12 matched control subjects by using the diffusion tensor imaging technique. Corticospinal dysgenesis was quantified by computing a symmetry index between the area of the contralateral and ipsilateral corticospinal tracts.
We hypothesized that the extent of infarction overlap with the cerebral hemispheric course of the corticospinal tract (CST) on structural MR imaging predicts the extent of ipsilateral cerebral peduncular atrophy in patients with chronic stroke.
Damage to the corticospinal tract (CST) in stroke patients has been associated with functional reorganization in the ipsilesional and contralesional sensorimotor cortices.
Mutations in the gene encoding the neural recognition molecule L1 result in hypoplasia of the corticospinal tract and path finding errors of corticospinal axons at the pyramidal decussation.
Pathological examination disclosed histological evidence of ALS, including loss of Betz cells and lower motor neurons, corticospinal tract degeneration, and Bunina bodies.
Immunohistological studies showed profound CD68 immunoreactivity in the lesion area and the contralateral lateral corticospinal tract in the spinal cord at all time points, demonstrating that microglia/macrophage remain reactive at the sites of injury and axonal degeneration/survival for at least 12 months.
ADC and FA were measured by means of regions of interest, positioned in the corticospinal tract at the level of the cerebral peduncle and at the level of the pons, in the transverse pontine fibers, in the superior and middle cerebellar peduncle, and in the hemispheric cerebellar white matter. It was significantly lower in SCA2 than in SCA1 in the transverse pontine fibers and in the corticospinal tract at the level of the cerebral peduncle.
Intrathecal administration of a function-blocking antibody to RGMa enhances anatomical synapse formation of the corticospinal tract in the cervical region of rats with thoracic spinal cord hemisection.
This paper reports experimental work in rats in which the radial nerve was cut at its origin from the brachial plexus and connected by means of a nerve graft to the corticospinal tract of the spinal cord at the T3-T4 level.
DTT clearly illustrated spinal projections such as the corticospinal tract and afferent fibers in control animals, and depicted the severed long tracts in the injured animals.
Our aim was to assess the relationship between muscle strength in MS and corticospinal tract (CST) abnormalities detected with multimodality MR imaging of the brain.
Transcranial magnetic stimulation (TMS) was initially used to evaluate the integrity of the corticospinal tract in humans non-invasively.
OBJECTIVES: Diffusion tensor image tractography (DTT) could be useful for exploring the state of the corticospinal tract (CST) at the level of the subcortical white matter.
These include the ipsilateral motor pathway from the unaffected motor cortex to the affected hand, peri-lesional reorganization, the recovery of a damaged lateral corticospinal tract, and contribution of the secondary motor area.
In treated animals the retrograde degeneration that normally follows corticospinal tract injury is absent. Rather, corticospinal tract axons sprout up to and into the lesion centre. In a behavioural test of corticospinal tract function, peptide treatment substantially improved recovery relative to controls.
Conventional MRI reveals hyperintensity along the corticospinal tract, hypointensity in the motor cortex, and atrophy of the precentral gyrus. Recent advances in magnetizing transfer imaging (MTI) provide more sensitive and accurate detection of corticospinal tract abnormality than conventional MRI. It shows reduced diffusion anisotropy in the corticospinal tract with good correlation with physiological index, reflecting UMN pathology.
PURPOSE: To investigate the feasibility of using spatial normalization in combination with diffusion tensor (DT) corticospinal tractography to assess corticospinal tract (CST) involvement in capsular or pericapsular stroke. MATERIALS AND METHODS: corticospinal tractograms were created and segmented out using DT imaging (DTI) data from 10 normal volunteers.
Examination with magnetic resonance diffusion tensor imaging (MRDTI), 6 days post-injury, showed a severe reduction in fractional anisotropy (FA) in the rostral pons containing the corticospinal tract, which correlated to the patient's severe hemiparesis.
We found that activity could be induced in the wrist extensors following stimulation of the filled region with onset delays comparable to undamaged corticospinal tract fibers in 5 out of 7 lesioned, FGF-2 treated rats. Furthermore, in the rats in which EMG activity could be elicited, long descending axons were labeled with projections into the spinal cord comparable to corticospinal tracts from undamaged motor cortex.
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects the corticospinal tract. Despite the correlation observed between ALSFRS scores and degeneration in PC and CI, our results suggest that this subjective scale is not a good parameter for the evaluation of the structural damage in encephalic portions of the corticospinal tract..
The goal of this study was to incrementally incorporate increasing levels of complexity into our computer models of STN DBS and address activation of the corticospinal tract (CST).
CONCLUSIONS: HFS of the STN preferentially activates the corticobulbar tract over the corticospinal tract.
Thereupon, the cortical forelimb area was electrophysiologically examined using micro-stimulation followed by tracing of the lesioned corticospinal tract (CST).
In this study, we investigated whether diffusion tensor MRI (DTI) could detect progressive corticospinal tract degeneration in amyotrophic lateral sclerosis (ALS) and whether changes in diffusion variables reflected clinical deterioration. Changes in fractional anisotropy (FA) and mean diffusivity (MD) were measured along the corticospinal tract using a region of interest approach. Although we confirmed that DTI detects corticospinal tract damage in ALS, there were no significant changes in diffusion measures over time.
We hypothesized that the early postnatal development of the corpus callosum and corticospinal tracts could be studied in unsedated healthy neonates by using novel approaches to diffusion tensor imaging (DTI) and quantitative tractography. DTI and structural images were coregistered and fractional anisotropy (FA), mean diffusivity (MD), and normalized T1-weighted (T1W) and T2-weighted (T2W) signal intensities were determined in central midline and peripheral cortical regions of the white matter tracts of the genu and splenium of the corpus callosum and the central midbrain and peripheral cortical regions of the corticospinal tracts by using quantitative tractography. As expected, MD decreased, FA increased, and T2W signal intensity decreased with increasing age in the genu and corticospinal tract, whereas there was no significant change in T1W signal intensity.
To evaluate corticospinal tract (CST) axon loss in EAE mice, we developed a direct tracing method with a fluorescent neuronal tracer DiI which was injected into the primary motor cortex and sensorimotor cortex to label the pyramidal neurons.
Children with diplegic cerebral palsy (CP) suffer from a bilateral supraspinal lesion of the corticospinal tract that occurs before the maturation of the CNS is complete. Although the rhythmic part of the modulation pattern was present in CP, there was no significant tonic reflex depression with age, thus reflecting a lack of maturation of the corticospinal tract.
The corticospinal tract (CST), superior longitudinal, inferior fronto-occipital and uncinatus fasciculi were reconstructed.
The residual bootstrap q-ball fiber tracking algorithm is capable of following the corticospinal tract and corpus callosum through regions of crossing white matter tracts in the centrum semiovale.
In the CNS, we used anterograde tracing with BDA to study corticospinal tract (CST) axons after spinal cord injury and transganglionic labelling with CT-HRP to trace ascending sensory dorsal column (DC) axons after DC lesions and a conditioning lesion of the sciatic nerve.
Myelin pallor of the lateral corticospinal tract was observed in two of the 10 cases.
RESULTS: In all 6 patients studied, DTI showed that the fibers of the superior cerebellar peduncles did not decussate in the mesencephalon and the corticospinal tract failed to cross in the caudal medulla.
Diffusion tensor tractography (DTT) is useful for exploring the state of the corticospinal tract (CST). The integrity of the corticospinal tract determined by DTT obtained during the early stage of a corona radiata infarct seems to be helpful in predicting the motor outcome of the affected hand..
We hypothesized that the early postnatal development of the corpus callosum and corticospinal tracts could be studied in unsedated healthy neonates by using novel approaches to diffusion tensor imaging (DTI) and quantitative tractography. DTI and structural images were coregistered and fractional anisotropy (FA), mean diffusivity (MD), and normalized T1-weighted (T1W) and T2-weighted (T2W) signal intensities were determined in central midline and peripheral cortical regions of the white matter tracts of the genu and splenium of the corpus callosum and the central midbrain and peripheral cortical regions of the corticospinal tracts by using quantitative tractography. As expected, MD decreased, FA increased, and T2W signal intensity decreased with increasing age in the genu and corticospinal tract, whereas there was no significant change in T1W signal intensity.
The purpose of this project is to study the dynamics of dieback in corticospinal tract (CST) axons after various time intervals post-injury, to find the optimal spatial-temporal window for regenerative treatment.
In two studies, electromyographic (EMG) responses in elbow flexors and extensors to stimulation of the motor cortex (MEPs) and corticospinal tract (CMEPs) were evoked before, during, and after infusion of hypertonic saline into biceps brachii to evoke deep pain.
The aim of this study was to evaluate the anatomical and clinical relationship between lacunar infarction and the corticospinal tract (CST) in patients with acute lacunar infarction and predict clinical outcome.
Here, we describe the quantitative magnetic resonance imaging (MRI) attributes of the major intracerebral motor pathway--the corticospinal tract--in multiple sclerosis. METHODS: In 75 individuals with multiple sclerosis and 29 healthy controls, the corticospinal tracts were reconstructed from diffusion tensor imaging at 3 T.
An anti-epileptic drug treatment with ethosuximide did not change the severity of the disease, and pigs with CPA did not exhibit the corticospinal tract axonal degeneration found in humans suffering from hereditary spastic paraplegia, which is associated with mutations in SPG4.
RESULTS: MRI revealed changes in the upper corticospinal tracts, splenium and, minimally, adjacent to the atria of the lateral ventricles. MRS showed decreased creatine, choline, N-acetylaspartate and glutamate and probably elevated lactate in the upper corticospinal tract but not in the normal-appearing frontal lobe. CONCLUSIONS: These results indicate early involvement of the upper corticospinal tract in adult-onset Krabbe disease.
Histological data and electrophysiological properties allowed reasonable assumptions of wave origin: wave I from extrapyramidal tracts, wave II from the ventral corticospinal tract, and wave III from the dorsal corticospinal tract.
We demonstrated the selective corticospinal tract (CST) and temporal lobe involvement using T1 spin-echo with an additional magnetization transfer contrast pulse on resonance (T1 SE/MTC) and FLAIR MR sequences in our patient, with further clinical and histopathological correlation.
Similar to the hand area, 10 min of stimulation with the anode over the leg area of the motor cortex increased the excitability of corticospinal tract projections to the tibialis anterior (TA) muscle, as reflected by an increase in the amplitude of the motor evoked potentials (MEPs) evoked by transcranial magnetic stimulation.
CONCLUSION: Diffuse tensor imaging is a useful tool for the visualization of white matter tracts, especially the corticospinal tract, which regulates motor function in human beings.
BACKGROUND AND PURPOSE: Our goal was to improve the preoperative assessment of the corticospinal tract (CST) in patients with brain tumors.
The mammalian corticospinal tract is known to contain axons that travel from the cerebral cortex to various levels of the spinal cord and its main function is thought to be the mediation of voluntary movement. The current study describes neuroanatomy related to the corticospinal tract of the giraffe. Our results, at least at the level of organization investigated herein, show that the corticospinal tract of the giraffe resembled that of a typical ungulate..
OBJECTIVES: The purpose of this study is to identity the recovery process of the corticospinal tract with diffuse axonal injury (DAI) using diffusion tensor imaging (DTI). CONCLUSIONS: Recovery in this patient could be attributed to the recovery of the corticospinal tract with diffuse axonal injury..
RESULTS: DTT showed that the origin of the corticospinal tract (CST) had changed from the posterior parietal cortex, primary sensory cortex, and primary motor cortex.
OBJECTIVES: Diffusion tensor image tracography (DTT) could be useful for exploration of the state of the corticospinal tract at the subcortical white matter level. This finding may reflect functional reorganization of the motor pathway following damage to the corticospinal tract..
A speculative explanation is that TMS might activate back muscles contralateral to arm abduction via an uncrossed, ipsilateral corticospinal tract that is slower conducting than the conventional crossed corticospinal tract.
In patients, reduced fractional anisotropy was found in bilateral corticospinal tracts, the left insula/ventrolateral premotor cortex, the right parietal cortex and the thalamus, which correlated with the ALSFRS-R. In ALS patients, our results show that subcortical lesions extend beyond the corticospinal tract and are clinically relevant..
METHODS: We examined 30 patients with first-ever unilateral hemiparetic stroke, 23 with subcortical lesions affecting the corticospinal tract, seven with cortical involvement.
Although axonal degeneration in the corticospinal tract was obvious caudal to the lesion site in both strains of mice after SCI, the number of surviving nerve fibers caudal to the lesion was significantly larger in neuropsin(-/-) mice than WT mice.
BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) was used as a noninvasive method to evaluate the anatomy of the corticospinal tract (CST) and the pattern of its degeneration in amyotrophic lateral sclerosis (ALS).
Quantitative behavioral analysis of forepaw function after cervical spinal cord injury in rats: Relationship to the corticospinal tract.
The functional integrity of the corticospinal tract (CST) is of crucial importance for fine and independent finger movement.
Greater mean diffusivity (MD) in boys was shown in the corticospinal tract and in frontal white matter in the right hemisphere; greater MD in girls was shown in occipito-parietal regions and the most superior aspect of the corticospinal tract in the right hemisphere.
We hypothesized that an increase in the activity in the motor cortex by cortical stimulation would increase its inhibitory influence on spinal excitability through the corticospinal tract and, thus, reduce the hyperactivity of the gamma and alpha neurons, improving spasticity.
MRI, obtained 13 days after the onset, demonstrated the infarct, mainly subcortical, extending throughout fronto-temporo-parietal areas and restricted diffusion in the ipsilateral corticospinal tract.
The purpose of the present study was to evaluate the influence of intracranial AVM on corticospinal tract and optic radiation tractography. RESULTS: In patients without hemorrhage, AI of optic radiation volume (P<.0001), AI of perinidal FA along corticospinal tract (P=.006), and optic radiation (P=.01) differed significantly between groups. In patients associated with hemorrhage, AI of corticospinal tract volume (P=.01), AI of perinidal FA along corticospinal tract (P=.04), and optic radiation (P=.004) differed significantly between groups. CONCLUSIONS: corticospinal tract and optic radiation tractography were visualized in patients with AVM.
RESULTS: When smaller isotropic voxels were used, the FA was greater in areas with crossing fibers, including the superior longitudinal fasciculus, the thalamus, and the red nucleus; the FA was not significantly different in areas without crossing fibers, such as the corpus callosum, the posterior limb of the internal capsule, and the corticospinal tract at the level of the centrum semiovale (P>.05).
We tried to investigate the motor outcome according to diffusion tensor tractography (DTT) findings for the corticospinal tract (CST) in the early stage for hemiparetic patients with intracerebral hemorrhage (ICH).
Previous results using paired-pulse transcranial magnetic stimulation (TMS) have suggested that the excitability of transcallosal (TC) connections between the hand areas of the two motor cortices is modulated by intracortical inhibitory circuits in the same way as corticospinal tract (CTS) projections to spinal motoneurons.
Intensely gamma1 laminin-positive, aggressive-looking reactive astrocytes of the lateral columns of both cervical and thoracic spinal cord surround the lateral ventral horns and roots and extend into the area of the lateral corticospinal tract.
crossed) corticospinal tract (contralateral SMC) and ipsilateral cerebellum. uncrossed) corticospinal tract (ipsilateral SMC) and the contralateral cerebellum are recruited.
OBJECTIVE: Ataxic hemiparesis (AH) is a well recognised lacunar syndrome involving homolateral ataxia with accompanying corticospinal tract impairment.
However, perinatal lesions of the corticospinal tract can lead to abnormal development of spinal reflexes that includes retention and reinforcement of developmental features that do not emerge in adult stroke victims, even though they also suffer from spasticity.
Our results show that the latency of the soleus electromyographic response is shortened by optokinetic stimulation, but the latency of the motor response evoked by the corticospinal tract is unchanged.
The purpose of this study was to use diffusion tensor imaging (DTI) with fiber tractography (FT) to demonstrate focal lesions of the corticospinal tract (CST) in hemiparetic patients with cerebral palsy (CP) who showed no specific focal lesions on conventional brain MRI.
RESULTS: On initial presentation, 17 patients with X-ALD had corticospinal tract lesions without splenium or genu involvement, 24 had symmetric corticospinal tract lesions with additional involvement of the splenium or genu, and 15 did not have corticospinal tract involvement but had other white matter lesions. In 18 of 21 patients with progressive lesions, corticospinal tract involvement preceded or occurred concurrently with progressive inflammatory demyelination. The involvement of the corticospinal tracts is prominent and may at times represent a variant course of progressive inflammatory demyelination..
Distinctive features in FA and T2 were found for the corticospinal tract and callosal fibers.
Mean FA, MD, and TD were recorded for regions of interest placed within the corpus callosum, corticospinal tract, putamen, optic radiation, and ventricular cerebral spinal fluid. With three averages, MDC was lowest within the corticospinal tract and putamen, where MDC was 0.04 for FA, below 30 x 10(-6) and 40 x 10(-6) mm2/s, respectively, for MD, and below 40 x 10(-6) mm2/s for TD.
Spinal cord injury models often involve damage to the corticospinal tract (CST) because of the functional importance of this pathway in humans.
CONCLUSIONS: Phasic contraction of remote muscles potentiates excitatory- and suppresses inhibitory intracortical neuronal pathways converging on corticospinal tract cells innervating the upper limb muscles even when they are active.
METHODS: Transcranial magnetic stimulation (TMS) characterized corticospinal tract development from each hemisphere over the first 2 years in 32 healthy children, 14 children with unilateral stroke, and 25 with bilateral lesions. Magnetic resonance imaging and anatomic studies compared corticospinal tract growth in 13 patients with perinatal stroke with 46 healthy subjects. Magnetic resonance imaging and anatomic studies demonstrated hypertrophy of the corticospinal tract from the noninfarcted hemisphere.
Our purpose is to investigate the plasticity of the corticospinal tract (CST) in early blindness by tract-based quantitative analysis of fractional anisotropy (FA).
Our data show that motor cortex stimulation for five consecutive days over two weeks ameliorates the voiding phase of the micturition cycle, suggesting that enhancing corticospinal tract excitability might be useful to ameliorate detrusor contraction and/or urethral sphincter relaxation in MS patients with bladder dysfunction..
corticospinal tract axons did not regrow beyond the lesion scar but extended distally into closer proximity to the injury site in AAV-L1-treated compared with control mice.
Sympathetic preganglionic neurons and interneurons are closely apposed (presumably synapsed upon) by corticospinal tract (CST) axons.
Using functional MRI and diffusion tensor tractography, we studied the topographical relation of hand and foot fibers of the corticospinal tract within the internal capsule to verify the recent unexpected finding by Holodny et al., who reported that hand fibers are located anterolateral to foot fibers, not anteromedial as is currently believed.
BACKGROUND AND PURPOSE: In amyotrophic lateral sclerosis (ALS), fiber degeneration within the corticospinal tract (CST) can be quantified by diffusion tensor imaging (DTI) as an indirect marker of upper motor neuron involvement. A new method of measuring quantitative DTI parameters using a probabilistic mixture model for fiber tissue and background in the corticospinal tract of patients with ALS is evaluated. CONCLUSION: The new software for fiber integrity quantification is suited to assess FA in the corticospinal tract with high reproducibility.
The corticospinal tract was labeled by injecting the anterograde tracer biotinylated dextran amine into the contralesional motor cortex.
Finally, anterograde tracing of the corticospinal tract of rats subjected to an incomplete SC transection showed no axonal fibers reaching the caudal stump.
We have integrated computational and neurophysiologic models including a 3D volume conduction head model computed using the finite element method, a realistic corticospinal tract (CST) model, and a geometry-specific axon activation model for the CST to predict the sites of activation along the CST as a function of electrode placement and stimulation voltage, which have been verified by epidural recordings.
We investigated whether compensatory reinnervation in the corticospinal tract (CST) and the corticorubral tract (CRT) is enhanced by the administration of bone marrow stromal cells (BMSCs) after experimental stroke.
We focus on two structures of the white matter with different properties and respectively known as the corpus callosum and the corticospinal tract..
In meningioma, DTT illustrated bulk displacement of the corticospinal tract in the affected hemisphere as well as preservation of the deviated axons.
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