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Neurology India 2021Hirayama disease (HD) is a motor neuron disease and occasionally is associated with lower limb hyper-reflexia. Corticospinal tract dysfunction can be evaluated by...
BACKGROUND
Hirayama disease (HD) is a motor neuron disease and occasionally is associated with lower limb hyper-reflexia. Corticospinal tract dysfunction can be evaluated by diffusion tensor imaging (DTI), but there is paucity of study in HD.
OBJECTIVE
We report corticospinal tract functions using DTI in the patients with HD and correlate with clinical findings.
MATERIALS AND METHODS
The patients with HD diagnosed on the basis of clinical and electromyography findings were included. Their age, duration of illness, side of initial involvement, and progression were noted. Presence of lower limb hyper-reflexia, and cervical spine magnetic resonance imaging (MRI) findings were noted. Cranial MRI was done and DTI findings at internal capsule, cerebral peduncle, pons, and pyramid were noted.
RESULTS
In total, 10 patients with HD and 5 matched controls were evaluated. The apparent diffusion coefficient (7.03 ± 0.27 vs 6.83 ± 0.36), fractional anisotropy (0.79 ± 0.04 vs 0.82 ± 0.05), axial diffusivity (5.08 ± 0.08 vs 5.04 ± 0.07), and radial diffusivity (3.79 ± 0.05 vs 3.76 ± 0.05) between HD patients and controls were not different in internal capsule. These values were also not significantly different in cerebral peduncle, pons, and pyramid. These values were also not significantly different between the severe and less severely affected sides. The fractional anisotropy did not correlate with lower limb hyper-reflexia (P = 1.00) and spinal cord atrophy (P = 0.60).
CONCLUSION
DTI study in HD patients did not reveal corticospinal tract involvement in brain.
Topics: Anisotropy; Diffusion Tensor Imaging; Humans; Pyramidal Tracts; Spinal Muscular Atrophies of Childhood
PubMed: 34507407
DOI: 10.4103/0028-3886.325338 -
Medicine Apr 2023We investigated the correlation between spasticity and the states of the corticospinal tract (CST) and corticoreticular tract (CRT) in stroke patients after early stage....
We investigated the correlation between spasticity and the states of the corticospinal tract (CST) and corticoreticular tract (CRT) in stroke patients after early stage. Thirty-eight stroke patients and 26 healthy control subjects were recruited. The modified Ashworth scale (MAS) scale after the early stage (more than 1 month after onset) was used to determine the spasticity state of the stroke patients. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), fiber number (FN), and ipsilesional/contra-lesional ratios for diffusion tensor tractography (DTT) parameters of the CST and CRT after the early stage were measured in both ipsi- and contra-lesional hemispheres. This study was conducted retrospectively. The FA and FN CST-ratios in the patient group were significantly lower than those of the control group (P < .05), except for the ADC CST-ratio (P > .05). Regarding the DTT parameters of the CRT-ratio, the patient group FN value was significantly lower than that of the control group (P < .05), whereas the FA and ADC CRT-ratios did not show significant differences between the patient and control groups (P > .05). MAS scores showed a strong positive correlation with the ADC CRT-ratio (P < .05) and a moderate negative correlation with the FN CRT-ratio (P < .05). We observed that the injury severities of the CST and CRT were related to spasticity severity in chronic stroke patients; moreover, compared to the CST, CRT status was more closely related to spasticity severity.
Topics: Humans; Retrospective Studies; Pyramidal Tracts; Stroke; Diffusion Tensor Imaging; Diffusion Magnetic Resonance Imaging; Anisotropy
PubMed: 37115067
DOI: 10.1097/MD.0000000000033604 -
The Journal of Neuroscience : the... Nov 1989The neuron-specific phosphoprotein B-50/GAP43 has been implicated in axonal outgrowth, since high levels of B-50/GAP43 are found in growth cones and during development...
The neuron-specific phosphoprotein B-50/GAP43 has been implicated in axonal outgrowth, since high levels of B-50/GAP43 are found in growth cones and during development of the nervous system. In adult brain, the B-50 levels are decreased. B-50 is primarily found in axons and presynaptic terminals. It is phosphorylated by protein kinase C, and this process has been implicated in the modulation of membrane signal transduction. During the outgrowth of the pyramidal tract, high levels of B-50 have been reported, whereas a low amount of B-50 persists into the adult stage. By immunoelectron microscopy, using immunogold labeling on cryosections and pre-embedding peroxidase labeling, we examined the distribution of B-50 in the pyramidal tract at the third cervical segment in developing 2-d-old and adult 90-d-old rats. B-50 immunoreactivity was found in axons and growth cones of the outgrowing tract. In the adult pyramidal tract, both unmyelinated and myelinated axons contained B-50 immunoreactivity. The immunogold label was predominantly located at the plasma membrane. Since the peroxidase reaction product was observed exclusively intracellularly, we conclude that the B-50 immunoreactivity is predominantly located at the cytoplasmic side of the plasma membrane of axons and growth cones. The high immunoreactivity in growth cones and axons of the outgrowing pyramidal tract further supports the hypothesis that B-50 plays a role in neurite outgrowth. The presence of B-50 in the adult pyramidal tract cannot merely be attributed to transport to the synapse. Therefore, it is suggested that B-50 plays, in addition, a local, growth-associated role in the adult tract.
Topics: Aging; Animals; Cell Membrane; GAP-43 Protein; Immunoenzyme Techniques; Membrane Proteins; Microscopy, Electron; Nerve Tissue Proteins; Phosphoproteins; Pyramidal Tracts; Rats; Rats, Inbred Strains; Synaptic Membranes
PubMed: 2531216
DOI: 10.1523/JNEUROSCI.09-11-03861.1989 -
AJNR. American Journal of Neuroradiology Jun 2008Diffusion tensor imaging (DTI) was introduced as a good technique to evaluate structural abnormalities in the white matter. In this study, we used DTI to examine...
BACKGROUND AND PURPOSE
Diffusion tensor imaging (DTI) was introduced as a good technique to evaluate structural abnormalities in the white matter. In this study, we used DTI to examine anisotropic changes of the pyramidal tracts displaced by chronic subdural hematoma (CSDH).
MATERIALS AND METHODS
Twenty-six patients with unilateral CSDH underwent DTI before and after surgery. We measured fractional anisotropy (FA) values in pyramidal tracts of bilateral cerebral peduncles and calculated the ratio of the FA value on the lesion side to that on the contralateral side (FA ratio) and compared the ratios with motor weakness. Moreover, the relationships between FA ratios and clinical factors such as age, sex, midline shift, interval from trauma, and hematoma attenuation on CT were evaluated.
RESULTS
FA values of pyramidal tracts on the lesion side were significantly lower than those on the contralateral side (0.66 +/- 0.07 versus 0.74 +/- 0.05, P < .0001). The FA ratio was correlated to the severity of motor weakness (r(2) = 0.32, P = .002). FA ratios after surgery improved significantly compared with those before surgery (0.96 +/- 0.08 versus 0.89 +/- 0.07, P = .0004). Intervals from trauma and the midline shift were significantly associated with decreased FA ratios (P = .0008 and P = .037).
CONCLUSIONS
In patients with CSDH, a reversible decrease of FA in the affected pyramidal tract on DTI was correlated to motor weakness. These anisotropic changes were considered to be caused by a reversible distortion of neuron fibers and vasogenic edema due to the hematoma.
Topics: Adult; Aged; Aged, 80 and over; Anisotropy; Diffusion Magnetic Resonance Imaging; Female; Hematoma, Subdural, Chronic; Humans; Image Interpretation, Computer-Assisted; Male; Middle Aged; Pyramidal Tracts; Reproducibility of Results; Sensitivity and Specificity; Statistics as Topic
PubMed: 18356470
DOI: 10.3174/ajnr.A1001 -
Medical Science Monitor : International... Mar 2021BACKGROUND The combined effects of bilateral corticospinal tract (CST) reorganization and interhemispheric functional connectivity (FC) reorganization on motor recovery...
BACKGROUND The combined effects of bilateral corticospinal tract (CST) reorganization and interhemispheric functional connectivity (FC) reorganization on motor recovery of upper and lower limbs after stroke remain unknown. MATERIAL AND METHODS A total of 34 patients underwent magnetic resonance imaging (MRI) examination at weeks 1, 4, and 12 after stroke, with a control group of 34 healthy subjects receiving 1 MRI examination. Interhemispheric FC in the somatomotor network (SMN) was calculated using the resting-state functional MRI (rs-fMRI). Fractional anisotropy (FA) of bilateral CST was recorded as a measure of reorganization obtained from diffusion tensor imaging (DTI). After intergroup comparisons, multiple linear regression analysis was used to explore the effects of altered FA and interhemispheric FC on motor recovery. RESULTS Interhemispheric FC restoration mostly occurred within 4 weeks after stroke, and FA in ipsilesional remained CST consistently elevated within 12 weeks. Multivariate linear regression analysis showed that the increase in both interhemispheric FC and ipsilesional CST-FA were significantly correlated with greater motor recovery from week 1 to week 4 following stroke. Moreover, only increased FA of ipsilesional CST was significantly correlated with greater motor recovery during weeks 4 to 12 after stroke compared to interhemispheric FC. CONCLUSIONS Our results show dynamic structural and functional reorganizations following motor stroke, and structure reorganization may be more related to motor recovery at the late subacute phase. These results may play a role in guiding neurological rehabilitation.
Topics: Aged; Anisotropy; China; Diffusion Tensor Imaging; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Pyramidal Tracts; Recovery of Function; Stroke
PubMed: 33707406
DOI: 10.12659/MSM.929092 -
AJNR. American Journal of Neuroradiology Mar 2007The underlying changes in the neuronal connectivity adjacent to brain tumors cannot always be depicted by conventional MR imaging. The hypothesis of this study was that...
Changes in fiber integrity, diffusivity, and metabolism of the pyramidal tract adjacent to gliomas: a quantitative diffusion tensor fiber tracking and MR spectroscopic imaging study.
BACKGROUND AND PURPOSE
The underlying changes in the neuronal connectivity adjacent to brain tumors cannot always be depicted by conventional MR imaging. The hypothesis of this study was that preoperative sensorimotor deficits are associated with impairment in pyramidal fiber bundles. Hence, we investigated the potential of combined quantitative diffusion tensor (DT) fiber tracking and MR spectroscopic imaging (MRSI) to determine changes in the pyramidal tract adjacent to gliomas.
MATERIALS AND METHODS
Quantitative DT fiber tracking and proton MRSI were performed in 20 patients with gliomas with WHO grades II-IV. Eight patients experienced preoperative sensorimotor deficits. Mean diffusivity (MD), fractional anisotropy (FA), and number of fibers per voxel (FpV) were calculated for the pyramidal tract of the ipsilateral and contralateral hemisphere. Metabolite concentrations for choline-containing compounds (Cho), creatine (Cr), and N-acetylaspartate (NAA) were computed, using LCModel, for all voxels located at the pyramidal tracts.
RESULTS
For the whole pyramidal tract, quantitative DT fiber tracking resulted in significantly lower FpV and FA values (P < .001), but not MD values, for the ipsilateral hemisphere. For the section of the fiber bundle closest to the lesion, we found significantly decreased FpV and FA (P < .001) and increased MD (P = .002). MRSI showed, for the same volumes of interest, significantly decreased NAA (P = .001), increased Cho (P = .034) and Cho/NAA (P = .001) for the ipsilateral pyramidal tract. In patients suffering sensorimotor deficits, we found significantly lower FA (P = .022) and higher MD values (P = .026) and a strongly negative correlation between FA and MD (R = -0.710, P = .024) but no correlation in patients without deficits (R = 0.078, ns).
CONCLUSION
Quantitative DTI was able to show significant differences in diffusivity of the pyramidal tract in patients with sensorimotor deficits in relation to patients without them. The additional use of proton MRSI may be helpful to discern whether these diffusivity changes in fiber tracts are caused by tumor infiltration or peritumoral edema.
Topics: Adult; Aged; Aspartic Acid; Astrocytoma; Brain Neoplasms; Creatine; Diffusion Magnetic Resonance Imaging; Female; Humans; Hypesthesia; Image Processing, Computer-Assisted; Magnetic Resonance Spectroscopy; Male; Middle Aged; Nerve Fibers; Oligodendroglioma; Paresis; Paresthesia; Protons; Pyramidal Tracts
PubMed: 17353313
DOI: No ID Found -
Neuron Jun 2021The ability to adjust one's behavioral strategy in complex environments is at the core of cognition. Doing so efficiently requires monitoring the reliability of the...
The ability to adjust one's behavioral strategy in complex environments is at the core of cognition. Doing so efficiently requires monitoring the reliability of the ongoing strategy and, when appropriate, switching away from it to evaluate alternatives. Studies in humans and non-human primates have uncovered signals in the anterior cingulate cortex (ACC) that reflect the pressure to switch away from the ongoing strategy, whereas other ACC signals relate to the pursuit of alternatives. However, whether these signals underlie computations that actually underpin strategy switching or merely reflect tracking of related variables remains unclear. Here we provide causal evidence that the rodent ACC actively arbitrates between persisting with the ongoing behavioral strategy and temporarily switching away to re-evaluate alternatives. Furthermore, by individually perturbing distinct output pathways, we establish that the two associated computations-determining whether to switch strategy and committing to the pursuit of a specific alternative-are segregated in the ACC microcircuitry.
Topics: Animals; Decision Making; Exploratory Behavior; Feeding Behavior; Gyrus Cinguli; Male; Pyramidal Tracts; Rats; Rats, Long-Evans
PubMed: 33852896
DOI: 10.1016/j.neuron.2021.03.028 -
The Journal of Neuroscience : the... Sep 2015The corticospinal and rubrospinal systems function in skilled movement control. A key question is how do these systems develop the capacity to coordinate their motor...
The corticospinal and rubrospinal systems function in skilled movement control. A key question is how do these systems develop the capacity to coordinate their motor functions and, in turn, if the red nucleus/rubrospinal tract (RN/RST) compensates for developmental corticospinal injury? We used the cat to investigate whether the developing rubrospinal system is shaped by activity-dependent interactions with the developing corticospinal system. We unilaterally inactivated M1 by muscimol microinfusion between postnatal weeks 5 and 7 to examine activity-dependent interactions and whether the RN/RST compensates for corticospinal tract (CST) developmental motor impairments and CST misprojections after M1 inactivation. We examined the RN motor map and RST cervical projections at 7 weeks of age, while the corticospinal system was inactivated, and at 14 weeks, after activity returned. During M1 inactivation, the RN on the same side showed normal RST projections and reduced motor thresholds, suggestive of precocious development. By contrast, the RN on the untreated/active M1 side showed sparse RST projections and an immature motor map. After M1 activity returned later in adolescent cat development, RN on the active M1/CST side continued to show a substantial loss of spinal terminations and an impaired motor map. RN/RST on the inactivated side regressed to a smaller map and fewer axons. Our findings suggest that the developing rubrospinal system is under activity-dependent regulation by the corticospinal system for establishing mature RST connections and RN motor map. The lack of RS compensation on the non-inactivated side can be explained by development of ipsilateral misprojections from the active M1 that outcompete the RST. Significance statement: Skilled movements reflect the activity of multiple descending motor systems and their interactions with spinal motor circuits. Currently, there is little insight into whether motor systems interact during development to coordinate their emerging functions and, if so, the mechanisms underlying this process. This study examined activity-dependent interactions between the developing corticospinal and rubrospinal systems, two key systems for skilled limb movements. We show that the developing rubrospinal system competes with the corticospinal system in establishing the red nucleus motor map and rubrospinal tract connections. This is the first demonstration of one motor system steering development, and ultimately function, of another. Knowledge of activity-dependent competition between these two systems helps predict the response of the rubrospinal system following corticospinal system developmental injury.
Topics: Animals; Axons; Brain Mapping; Cats; Electric Stimulation; GABA Agonists; Motor Cortex; Motor Skills; Muscimol; Pyramidal Tracts; Red Nucleus; Spinal Cord
PubMed: 26424884
DOI: 10.1523/JNEUROSCI.1719-15.2015 -
Brain Research Bulletin Sep 2018Pigs and minipigs are increasingly used as non-primate large animal models for preclinical research on nervous system disorders resulting in motor dysfunction. Knowledge...
BACKGROUND
Pigs and minipigs are increasingly used as non-primate large animal models for preclinical research on nervous system disorders resulting in motor dysfunction. Knowledge of the minipig pyramidal tract is therefore essential to support such models.
AIM AND METHODS
This study used 5 female Göttingen minipigs aging 11-15 months. The Göttingen minipig corticospinal tract was investigated, in the same animals, with in vivo neuronal tracing and with postmortem diffusion weighted MRI tractography to provide a thorough insight in the encephalic distribution of this primary motor pathway and its decussation at the craniocervical junction.
RESULTS
The two methods similarly outlined the course of the pyramidal tract from its origin in the motor cortex down through the internal capsule to the craniocervical junction, where both methods displayed an axonal crossover at the pyramid decussation. The degree of crossover was quantified with unbiased stereology, where 81-93% of the traced corticospinal fibers crossed to the contralateral spinal cord. Accordingly, in the upper cervical spinal cord the corticospinal tract is primarily distributed in the contralateral lateral funiculus and in close relation to the gray matter, wherein some direct terminations on large ventral column gray matter neurons could be identified.
DISCUSSION
The combination of neuronal tracing and tractography exploited the strengths of the respective methods to gain a better understanding of the encephalic distribution and craniocervical decussation of the Göttingen minipig corticospinal tract. Moreover, a quantification of the crossing fibers was obtained from the tracing data, which was not possible with tractography. Our data indicate that the porcine corticospinal system is quite lateralized down to the investigated upper cervical levels. However, further elucidation of this point will require a full examination of the corticospinal tracing pattern into the caudal spinal cord combined with an analysis of the direct versus indirect termination pattern on the lower motor neurons.
Topics: Animals; Female; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Motor Cortex; Neuroanatomical Tract-Tracing Techniques; Neurons; Pyramidal Tracts; Swine; Swine, Miniature
PubMed: 30086351
DOI: 10.1016/j.brainresbull.2018.08.004 -
The Journal of Neuroscience : the... Apr 2022The control of contraction strength is a key part of movement control. In primates, both corticospinal and reticulospinal cells provide input to motoneurons....
The control of contraction strength is a key part of movement control. In primates, both corticospinal and reticulospinal cells provide input to motoneurons. Corticospinal discharge is known to correlate with force, but there are no previous reports of how reticular formation (RF) activity modulates with different contractions. Here we trained two female macaque monkeys (body weight, 5.9-6.9 kg) to pull a handle that could be loaded with 0.5-6 kg weights and recorded from identified pyramidal tract neurons (PTNs) in primary motor cortex and RF cells during task performance. Population-averaged firing rate increased monotonically with higher force for the RF, but showed a complex profile with little net modulation for PTNs. This reflected a more heterogeneous profile of rate modulation across the PTN population, leading to cancellation in the average. Linear discriminant analysis classified the force based on the time course of rate modulation equally well for PTNs and RF cells. Peak firing rate had significant linear correlation with force for 43 of 92 PTNs (46.7%) and 21 of 46 RF cells (43.5%). For almost all RF cells (20 of 21), the correlation coefficient was positive; similar numbers of PTNs (22 vs 21) had positive versus negative coefficients. Considering the timing of force representation, similar fractions (PTNs: 61.2%; RF cells: 55.5%) commenced coding before the onset of muscle activity. We conclude that both corticospinal and reticulospinal tracts contribute to the control of contraction force; the reticulospinal tract seems to specify an overall signal simply related to force, whereas corticospinal cell activity would be better suited for fine-scale adjustments. For the first time, we compare the coding of force for corticospinal and reticular formation cells in awake behaving monkeys, over a wide range of contraction strengths likely to come close to maximum voluntary contraction. Both cortical and brainstem systems coded similarly well for force, but whereas reticular formation cells carried a simple uniform signal, corticospinal neurons were more heterogeneous. This may reflect a role in the gross specification of a coordinated movement, versus more fine-grained adjustments around individual joints.
Topics: Animals; Female; Macaca; Motor Cortex; Motor Neurons; Muscle Contraction; Pyramidal Tracts; Reticular Formation
PubMed: 35241490
DOI: 10.1523/JNEUROSCI.0627-21.2022