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PubMed1988

[Central motor conduction time in multiple sclerosis: an comparison of visual and somatosensory evoked potentials in relation to the type of disease course].

The central motor conduction time (CMCT) was measured by electrical transcranial and spinal stimulation in 70 consecutively admitted patients with definite multiple sclerosis and 26 normal volunteers. The results of the patientgroup were compared with visual and somatosensory (median and tibial nerve) evoked potentials. The mean CMCT of the volunteers was 5.4 ms versus 11.1 ms in the patient group. In 55 of the 70 patients (79%) the CMCT was delayed (p less than 0.0001). VEP showed pathologic results in 67%, SEP of tibial nerve in 51%, SEP of median nerve in 41% of the patients. In 10 of the 70 cases (15%) only CMCT was pathologic. Especially in the first attack of the disease the CMCT (79% pathologic results) was superior in comparison to the evoked potentials (VEP and SEP together 43% pathologic findings). In our cases without clinical evidence of a pyramidal tract lesion a subclinical affection of this pathway could be determined in 69% by a pathologic CMCT. We regard this method therefore as a valuable tool in the early diagnosis of multiple sclerosis.

Adult↗
PubMed1997

MR of childhood metachromatic leukodystrophy.

PURPOSE: To investigate the MR findings of childhood metachromatic leukodystrophy (MLD). METHODS: Nine MR imaging studies in seven children (five girls and two boys, 10 to 32 months old) with MLD were evaluated retrospectively for the extent and progression of white matter abnormalities and the presence of contrast enhancement. RESULTS: All seven cases showed symmetric, confluent high signal intensity on T2-weighted images in the periventricular white matter and centrum semiovale. A posterior predominance of white matter abnormalities was noted in all cases. Although initially spared from demyelination in all cases, in one case, the subcortical U fibers were later involved in demyelination of follow-up MR studies. Other sites of involvement were the genu (n = 5) and splenium (n = 6) of the corpus callosum, the posterior limbs of the internal capsule (n = 5), the descending pyramidal tracts (n = 4), the claustrum (n = 4), and the cerebral white matter (n = 2); diffuse brain atrophy was seen in two cases. No enhancement of the lesion was seen on any of the five postcontrast examinations. A "tigroid" pattern, previously described in cases of Pelizaeus-Merzbacher disease, was noted in the centrum semiovale in six cases. CONCLUSION: In late-infantile MLD, demyelination is more prominent in the occipital region. In addition to demyelination of the periventricular white matter, common manifestations include a "tigroid" pattern and involvement of the corpus callosum, the internal capsule, and the corticospinal tract.

Brain↗
PubMed1975

Outline of the arcuate nucleus in the human medulla oblongata.

The outline of the arcuate nucleus in the human medulla oblongata was studied in a series of serial sections of brain stems of newborn and young children. The nucleus lies on the ventral aspect of the pyramid. At higher levels the nucleus lies on the ventral and medial aspect of the pyramid. In the upper regions of the medulla the two nuclei fuse together, giving rise to a median dorsal extension, which in the uppermost part of the medulla extends to the floor of the fourth ventricle. The nucleus sends numerous branches to the corticospinal portion of the pyramidal tract, while the dorsal extension of the arcuate nucleus sends numerous transverse rays on either side which consist of nerve fibres and cells. These rays extend in the areas of the medulla occupied by the medial lemniscus, tectospinal portion, and medial longitudinal bundle. The significance of the findings is discussed.

Age Factors↗
PubMed2005

Contribution of the motor cortex to the structure and the timing of hindlimb locomotion in the cat: a microstimulation study.

We used microstimulation to examine the contribution of the motor cortex to the structure and timing of the hindlimb step cycle during locomotion in the intact cat. Stimulation was applied to the hindlimb representation of the motor cortex in 34 sites in three cats using either standard glass-insulated microelectrodes (16 sites in 1 cat) or chronically implanted microwire electrodes (18 sites in 2 cats). Stimulation at just suprathreshold intensities with the cat at rest produced multi-joint movements at a majority of sites (21/34, 62%) but evoked responses restricted to a single joint, normally the ankle, at the other 13/34 (38%) sites. Stimulation during locomotion generally evoked larger responses than the same stimulation at rest and frequently activated additional muscles. Stimulation at all 34 sites evoked phase-dependent responses in which stimulation in swing produced transient increases in activity in flexor muscles while stimulation during stance produced transient decreases in activity in extensors. Stimulation with long (200 ms) trains of stimuli in swing produced an increased level of activity and duration of flexor muscles without producing changes in cycle duration. In contrast, stimulation during stance decreased the duration of the extensor muscle activity and initiated a new and premature period of swing, resetting the step cycle. Stimulation of the pyramidal tract in two of these three cats as well as in two additional ones produced similar effects. The results show that the motor cortex is capable of influencing hindlimb activity during locomotion in a similar manner to that seen for the forelimb.

Animals↗
PubMed2004

Anti-Hu associated paraneoplastic sensory neuronopathy with upper motor neurone involvement.

Paraneoplastic neurological syndrome is characterised by neuronal degeneration with lymphocytic infiltration in various regions of the central and peripheral nervous systems. Motor neurone symptoms may occur as a remote effect of malignancy, and have been considered because of the involvement of lower motor neurones. A case is reported of an 80 year old woman suffering from paraneoplastic sensory neuronopathy with anti-Hu antibody. Postmortem examination showed adenocarcinoma of the gall bladder and small cell carcinoma of the duodenum. Neuronal loss with lymphocytic infiltration was found in the dorsal root ganglia, brain stem, and cerebellum. Despite the absence of upper motor neurone signs, there was severe loss of Betz cells and degeneration of the bilateral pyramidal tracts. To our knowledge, this is the first demonstration of upper motor neurone involvement in anti-Hu associated paraneoplatic syndrome.

Adenocarcinoma↗
PubMed1975

Cortical motor representation in view of recent experiments on cortico-spinal relations.

The results of recent experiments using either intracortical stimulation or stimulation of the surface of the motor cortex were reviewed from the point of view of "muscle" and "movement" cortical representation. It has been concluded that there is no satisfactory evidence for location of the pyramidal tract (PT) cells which project directly (monosynaptically) to motoneurones of one muscle in primates within small and separate cortical areas; such evidence is even weaker for PT cells which exert their effects via polysynaptic pathways in other species. The available evidence shows in contrast a very pronounced overlap of cortical areas of projection to different motor nuclei.

Animals↗
PubMed1997

Persistence of layer IV in the primary motor cortex (area 4) of children with cerebral palsy.

The normal development of the human primary motor cortex is characterized by a cytoarchitectonic transformation from the fetal, six-layered cortex to the adult, five-layered agranular cortex. The present study examines whether this transformation also occurs in children with cerebral palsy. Nissl-stained, serial sections through the left precentral gyrus of 14 children (age: 3-13 years) with cerebral palsy and from a control group without any clinically manifested disturbances of the motor system were analyzed. The widths of cortical layers, the laminar distributions of area 1 fractions occupied by cell bodies and neuropil, and the numerical densities and mean sizes of cell bodies were measured. In 5 cases of cerebral palsy, an inner granular layer (IV) persisted up to ages between 3 and 9 years. Layer IV was absent in other cases and in the controls. The persistence of layer IV was closely related to severe impairments of posture: all children with persistent layer IV were unable to maintain an upright posture. Cytoarchitectonic differences to controls were also found in other layers. Layer V, the major source of the pyramidal tract, was more narrow in children with cerebral palsy. The ratio between average cell body size for layers III and V was changed in the group of cerebral palsy. Thus, severe impairment of posture can be associated with disturbed cytoarchitectonic development of the motor cortex.

Adolescent↗
PubMed2006

Between session reproducibility and between subject variability of diffusion MR and tractography measures.

As diffusion tractography is increasingly used to generate quantitative measures to address clinical questions, it is important to characterise the inter-session reproducibility and inter-subject variability of these measures. Here, we assess the reproducibility and variability of diffusion tractography measures using diffusion data from 8 subjects scanned 3 times. We used probabilistic tractography to define the cingulum bundle, pyramidal tracts, optic radiations and genu of the corpus callosum in each individual data set using three different methods of seed definition. Measures of mean fractional anisotropy (FA) and mean diffusivity (MD) along the tracts were more reproducible than measures of tract volume. Further, tracts defined using a two region of interest (ROI) approach were more reproducible than those defined using manually placed seed masks alone. For mean FA taken from tracts defined using the two ROI approach, inter-session coefficients of variation (CV) were all below 5% and inter-subject CVs were below 10%; for mean MD inter-session, CVs were all below 3% and inter-subject CVs were below 8%. We use the variability measures found here to calculate the sample sizes required to detect changes in FA, MD or tract volume of a given size, either between groups of subjects or within subjects over time. Finally, we compare tractography results using 60 diffusion encoding directions to those found using a subset of 12 directions; the number of diffusion directions did not have a significant effect on reproducibility, but tracts derived using fewer directions were consistently smaller than those derived using 60 direction data. We suggest that 12 direction data are sufficient for reproducibly defining the core of large bundles but may be less sensitive to smaller pathways.

Adult↗
PubMed1978

Intracellular recordings from the motor cortex during EEG arousal in unanaesthetized brain preparations of the cat.

1. Intracellular recordings were made from 92 neurones in the precruciate cortex of encéphale isolé and midpontine pretrigeminal preparations of the cat. 2. All but only one of these cells showed appreciable changes in the membrane potential during the transition from the cortical slow wave phase to the EEG arousal occurring spontaneously or induced by stimulating the midbrain reticular formation. Thus, 38 cells were depolarized (D-type cells), 48 cells hyperpolarized (H-type cells) and 5 cells showed an early hyperpolarization and a later depolarization (mixed type). 3. The latency of intracellular responses to reticular stimulation was shorter in the D-type cells than the H-type or mixed-type cells, and shorter for each of the D- and H-types in the cells of the superficial layers than those of the deep layers. 4. The D-type cells were distributed widely through laminae I to V, but the majority was sampled in lamina II. The H-type cells were located in laminae III-VI with the mode at the upper half of lamina III. The mixed-type cells were mostly located in laminge V and VI. 5. Antidromically identified slow pyramidal tract (PT) cells n=9) all belonged to the D-type, and fast PT cells either to the H- (n=11) or the mixed type (n=4). 6. These results suggest that the EEG arousal is a state composed of both excitatory and inhibitory responses of cortical cells which are processed from the superficial to the deep layers.

Animals↗
PubMed1999

Generation of rhythmical ingestive activities of the trigeminal, facial, and hypoglossal motoneurons in in vitro CNS preparations isolated from rats and mice.

The central pattern generator (CPG) for masticatory movements has been located in the medial bulbar reticular formation, by using cortically induced rhythmical jaw and tongue movements as a model. To analyze how stationary input from the cortex is transformed into rhythmical output in the neuronal population comprising the CPG, rhythmical neural activities representing rhythmical food ingestive movements were experimentally induced in vitro. Bath-application of N-methyl-D-aspartate (NMDA) induced rhythmical activities in the trigeminal (V), facial (VII) and hypoglossal (XII) nerves of in vitro brainstem-spinal cord preparations isolated from newborn rats and mice. This paper will review evidence for the notion that (1) the rhythmical XII nerve activity represents rhythmical sucking movements; (2) the population of neurons critically involved in the rhythm generation of the XII nerve is localized in the ventromedial medulla oblongata on both sides, and can induce rhythmical XII nerve activity on the same side independently of each other; (3) the rhythmical activities in the V, VII, and XII motoneurons are induced by separate CPGs, which are located segmentally at the respective level of the V motor, VII, and XII nuclei. In addition, rhythmical masticatory-like EMG activity of jaw muscles can be induced by repetitive stimulation of the pyramidal tract in the in vitro brainstem isolated from adult mice together with the oral-facial structures. We propose that the in vitro brainstem preparation is a useful tool for longitudinal analysis of postnatal development of the central pattern generation of food ingestive movements, including conversion from sucking to mastication.

Age Factors↗
PubMed1995

[Neurological involvements with transient gait disturbance in subacute phase of Kawasaki disease; a case report].

A 1-year-and-9-months old boy with gait disturbance during the 3rd week of Kawasaki disease (KD) was described. He had been previously healthy, and developed high fever and rash. The diagnosis of KD was based on 5 of 6 major criteria on the 3rd clinical day. He was initially treated with intravenous gamma-globulin 400 mg/kg/day for five days. On the 17th clinical day, the patient developed gait disturbance after most clinical signs disappeared. His gait was wide- based and unstable. Generalized hypotonia with poor traction response was also seen. Pyramidal tract signs including exaggerated patellar and Achilles tendon reflexes and positive bilateral Mendel-Bechterew reflex were presented. Cerebrospinal fluid was normal. Brain CT, MRI, and 123I-IMP SPECT images were normal without broad hemorrhage or infarction of the cerebral parenchyma. Gait disturbance recovered spontaneously within one month without any sequelae.

Central Nervous System Diseases↗
PubMed1976

Anticipatory activity of motor cortex neurons in relation to direction of an intended movement.

1. Monkeys were trained to 1) hold a handle in a central zone midway between "push" and "pull" while awaiting 2) an instruction telling them how to respond to a subsequent 3) perturbation, which triggered the instructed movement and was followed by 4) a reward if the movement was correct. 2. There were two sorts of instructions: push and pull. When the pull instruction had preceded the perturbation, the monkey responded to the perturbation by pulling, whereas after a push instruction, the monkey responded to the perturbation by pushing. 3. Recordings in pre- and postcentral sensorimotor cortex revealed instruction-induced changes of neuronal activity during the period intervening between the instruction and the perturbation-triggered movement. Effects of the instruction were differential depending on which of the two instructions was given, such differential responses to the instruction being detected in 61% of precentral pyramidal tract neurons (PTNs), 44% of precentral non-PTNs, and 11% of postcentral neurons. 4. Since motor cortex PTN axons end on alpha and gamma motoneurons and on interneurons of the spinal cord, changes of PTN activity with "intention" or "motor set" provide a mechanism for suprasegmental control and presetting of spinal cord reflex excitability specific to the nature of an impending movement.

Animals↗
PubMed1992

MRI and SPECT findings in amyotrophic lateral sclerosis. Demonstration of upper motor neurone involvement by clinical neuroimaging.

MRI was performed in 21 patients and single photon emission computed tomography (SPECT) with N-isopropyl-p-123I iodoamphetamine in 16 patients, to visualize upper motor neurone lesions in amyotrophic lateral sclerosis. T2-weighted MRI revealed high signal along the course of the pyramidal tract in the internal capsule and cerebral peduncle in 4 of 21 patients. SPECT images were normal in 4 patients, but uptake was reduced in the cerebral cortex that includes the motor area in 11.

Adult↗
PubMed1991

Organization of the mouse motor cortex studied by retrograde tracing and intracortical microstimulation (ICMS) mapping.

The motor representation of the body musculature was studied in 11 adult mice by using ICMS. The motor responses elicited from both granular and agranular cortical fields showed that the mouse motor cortex is topographically organized; however, within the representation of individual body-parts the movements are multiply represented. In addition, several sites were encountered where more than one movement was elicited at the same stimulus threshold. The locations of pyramidal cells contributing axons to the pyramidal tract were examined by means of retrograde tracing with HRP injected into the cervical enlargement. This procedure labeled neurons only in lamina V in granular and agranular cortical fields. The similarities between the organization of motor cortex demonstrated in this study and the organization in the rat suggest that the rat and mouse share a common plan of rodent motor cortical organization.

Animals↗
PubMed2001

Cotton wool plaques in non-familial late-onset Alzheimer disease.

Cotton wool plaques (CWP) are large, ball-like plaques lacking dense amyloid cores that displace adjacent structures. They were first described in a Finnish kindred with early-onset Alzheimer disease (AD) with spastic paraparesis due to a presenilin-1 delta9 mutation. We describe a case of sporadic late-onset AD with numerous neocortical CWP as well as severe amyloid angiopathy and marked leukoencephalopathy, compared with 16 cases of late-onset AD with similar degrees of amyloid angiopathy and leukoencephalopathy. The cases were studied with histologic methods and with single and double immunostaining for beta-amyloid (Abeta), paired helical filaments-tau (PHF-tau), neurofilament (NF), glial fibrillary acidic protein (GFAP), HLA-DR, and amyloid precursor protein (APP). We found that CWP were well-circumscribed amyloid deposits infiltrated by ramified microglia and surrounded by dystrophic neurites that were immunopositive for APP, but only weakly for NF and PHF-tau. Abeta1-12 was diffuse throughout the CWP, while Abeta37-42 was peripherally located and Abeta20-40 more centrally located. Two of the 16 late-onset AD cases also had CWP, but they were also admixed with diffuse plaques and plaques with dense amyloid cores. Pyramidal tract degeneration was not a consistent finding or a prominent feature in any case. The results suggest that CWP are not specific for early-onset familial AD with spastic paraparesis.

Age of Onset↗
PubMed1990

IgG reactivity in the spinal cord and motor cortex in amyotrophic lateral sclerosis.

The spinal cord and motor cortex of patients with amyotrophic lateral sclerosis (ALS) were examined with immunohistochemical methods for the presence of IgG. In 13 of 15 spinal cords, a population of motoneurons stained positively for IgG in a granular pattern, characteristic of binding to the rough endoplasmic reticulum. In 6 of 11 motor cortices, a proportion of pyramidal cells also stained positively for IgG. No such reactivity was noted in motoneurons of control human tissues, although positive IgG staining was present in astrocytes of ALS and control specimens. Reactive microglia and/or macrophages were detected in the territory of degenerating pyramidal tracts and ventral horns. The surface of most of these cells stained positively for IgG, and 50% stained positively for HLA-DR. The accumulation of IgG in motoneurons and the presence of immunologically active macrophages provide additional evidence for the participation of immunologic factors in the pathogenesis of ALS.

Adult↗
PubMed2002

Distribution and course of cortico-respiratory projections for voluntary activation in man. A transcranial magnetic stimulation study in healthy subjects and patients with cerebral ischemia.

The function and course of the cortico-respiratory projections in man are not yet well established. In 30 normal volunteers respiratory muscles were activated by magnetic stimulation of the motor cortex and the cervical and thoracic spinal roots with bilateral recordings from the respiratory muscles. Following cortical stimulation contralateral responses were obtained in all subjects during voluntary inspiration showing a mean latency and amplitude of 13.4+/-1.4ms/1.6+/-1.2 mV (stimulation of the left hemisphere) and 13.2+/-1.3ms/2.5+/-2.5 mV (stimulation of the right hemisphere). Ipsilateral responses were obtained in only 18 (right side) and 21 (left side) subjects and had a significantly (p < 0.001) longer mean latency and lower mean amplitude than the contralateral responses. In 31 patients with impairment of the cortico-respiratory projections due to cerebral infarction demonstrated by magnetic resonance imaging studies, the responsible lesion topography was analysed. We found that, 1. the voluntary activation of respiratory muscles is mediated predominantly by the contralateral motor cortex, 2. the descending cortico-respiratory projections are located within the pyramidal tract, and 3. the cortico-respiratory projections to the respiratory muscles are frequently affected in patients with hemiparesis due to acute stroke. These findings might explain the increased incidence of pneumonia at the hemiparetic side in patients with cerebral ischemia as shown in previous studies.

Adult↗