[Intervention of exclusion of the pyramidal pathways in the modifications of vascular tonus following experimental brain lesions].
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Brain↗
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Results for “Pyramidal Tracts”
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Pyramid irritation syndrome; test for hierarchical classification of clinical signs making it possible to search for it.
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Humans↗
[A clinicopathological study of familial amyotrophic lateral sclerosis with special reference to the mode of motoneuron loss in the spinal ventral horn].
The authors analyzed clinicopathologically eight patients with familial amyotrophic lateral sclerosis (F-ALS). We performed the morphometric analysis on size and topographical distribution of the fourth lumbar spinal ventral horn cells, and correlated thus obtained results with the clinical, genetic and neuropathological features of these cases. The patients were consisted of six men and two women with age ranged between 40 and 58 years old. Six cases among them were involved predominantly in the lower-legs with generalized hyporeflexia and no Babinski's sign, which were compatible with the "pseudopolyneuritic" as a clinical form. Two other cases were involved in the upper limbs as the initial symptom and were considered to be "common form". Pathologically, five cases showed multiple system degenerations including the middle root zone of the posterior columns, Clarke's nuclei and posterior spinocerebellar tracts as well as the ventral horns and pyramidal tracts, which were designated as the form of "multiple system degeneration". In addition, three in these five cases were also associated with an extensive neuron loss and marked gliosis in the Onuf's nuclei, subthalamic, red and cerebellar dentate nuclei, suggesting that the involvement in certain F-ALS cases with a form of multiple system degeneration is more extensive in topography than ever believed. In other three cases, the neuronal degenerations were considerably restricted in the somatic motor efferent system, which were consistent with the classical pathology of the sporadic ALS, and were designated as "classical form". Five of seven cases showed a severe motoneuron loss in both the large and small neurons in the ventral horn. These five cases were heterogeneous in the pathological forms "multiple system degeneration" or "classical", but all were "pseudopolyneuritic" in clinical form. Moreover, these extensive motor neuron loss including small ones in the spinal ventral horn was similarly observed in the sporadic pseudopolyneuritic form of ALS cases. In two cases of F-ALS with "common" in clinical form, large motoneurons were fairly well preserved as are in the common form of sporadic ALS cases. Our tentative conclusion is that mode of motoneuron loss in the spinal ventral horn of F-ALS is more correlated to the clinical manifestations rather than the pathological or genetic background.
Adult↗
Axon ramification following unilateral cortical ablation in neonatal rats.
We confirmed the formation of an aberrant ipsilateral corticospinal tract after unilateral cerebral cortical ablation during the neonatal period in rat. This tract was studied using anterograde horseradish peroxidase (HRP) tracing. Ramifications of the axons in the pyramidal tract were found to contribute to the ipsilateral tract at the level of the pyramidal decussation, suggesting that ramification of immature axons play an important role in the formation of the ipsilateral corticospinal tract.
Animals↗
The Duke experience with the nucleus caudalis DREZ operation.
The nucleus caudalis DREZ operation has been performed in three phases at Duke. Between 1982 and 1988 radiofrequency (RF) lesions were made in the trigeminal nucleus extending from the C2 root to the obex using a straight electrode. Complications include ipsilateral arm ataxia due to spinocerebellar tract injury and ipsilateral lower limb weakness from the pyramidal tract. The former occurred at least transiently in 90% of cases. The electrode employed from 1988 to 1989 had proximal insulation protecting the spinocerebellar tract. Since 1989 a ninety degree bend has been added to the electrode to allow better placement. Two electrodes are used to accommodate the shape of the caudalis nucleus. A total of 101 procedures have been performed. The newest electrodes were used in 46 procedures. Ataxia is recognized in 39%. Overall pain relief was excellent in 34% and good in 40%. In post herpetic neuralgia 71% enjoyed excellent or good relief. Indications include post herpetic neuralgia, deafferentation pain (anaesthesia dolorosa, post-tic dysesthesia, stroke, MS, gasserian tumour, Gamma Knife radiation injury), facial trauma/surgery, atypical facial pain, and migraine/cluster headache. A study to compare this operation to deep brain stimulation prospectively for the above indications has been initiated.
Afferent Pathways↗
Nitric oxide signalling system in rat brain stem: immunocytochemical studies.
Nitric oxide is a free radical, which is produced in several tissues of the body and is thought to be the first of a new class of neural messenger molecules and a retrograde modulator of synaptic transmission in the brain. Nitric oxide synthase (NOS) is the enzyme that produces nitric oxide from the substrate l-arginine. The pattern of the distribution of neuronal isoform of NOS was investigated in neurones and fibres in the brain stem using standard immunocytochemistry. In our results, NOS positive neurones and processes were seen in the spinal trigeminal nucleus, gracile nucleus, nucleus of the solitary tract, nucleus ambiguus, reticular nuclei and lateral to the pyramidal tract of the medulla. In the pons, heavily labelled NOS containing neurones were seen in the pedunuclopontine tegmental nucleus, ventral tegmental nucleus and in the laterodorsal tegmental nucleus. The localization of neuronal NOS expressing neurones suggests a widespread neuromodulatory role for the nitric oxide in the central nervous system of rat.
Animals↗
Progressive ponto-bulbar palsy with deafness. A clinico-pathological study.
Progressive ponto-bulbar palsy with deafness is a rare disease. It seems to be an abiotrophic process with autosomal recessive inheritance in most instances. Only one autopsy case had been briefly described (Lelong et al., 1941). The clinical features and the pathological findings of a new case are reported. The structures primarily involved are the grey matter of the brain stem and the spinal cord, including to some extent the optic tracts and most of the fiber tracts in the brain stem with exception of the pyramidal tracts.
Adolescent↗
The neuropathology of cerebrotendinous xanthomatosis revisited: a case report and review of the literature.
Cerebrotendinous xanthomatosis (CTX), a rare autosomal-recessive lipid storage disease, has been well characterized clinically and biochemically, and recently also from the molecular biological aspect. However, only a very few publications deal with its neuropathology, and views on its pathogenesis vary. Based on a recently examined case, we propose that central-peripheral distal axonopathy is the major pathogenetic mechanism of nervous system injury in CTX. The latter is characterized by white matter pathology, typically in form of long tract involvement with the more distal parts of the tract more severely affected. Most severely affected are the cerebellar white matter, the optic pathways and the long tracts of the brain stem and spinal cord, particularly the pyramidal tracts, although there is hardly a CNS region which does not display some form of pathology. Lesions are characterized by loss of myelinated fibers and accumulation of lipid products in form of foamy macrophages, clear oil-red-O-positive spaces and crystalline clefts, accompanied by gliosis, occasional axonal spheroids, and in the cerebellum--the most severely affected structure--also by multi-nucleated foreign body giant cells. Demyelination is not seen, and ultrastructurally myelin sheaths are normally structured. Signs of axonal degeneration are also present in the spinal roots. We hypothesize that the basic enzymatic defect in CTX leads to accumulation of metabolites in the brain which may be neurotoxic and may impair the metabolic apparatus of neurons with resultant axonopathy and subsequent nonspecific lipid deposition in the injured tracts.
Adult↗
Spontaneous firing patterns and axonal projections of single corticostriatal neurons in the rat medial agranular cortex.
1. Spontaneous fluctuations of membrane potential, patterns of spontaneous firing, dendritic branching patterns, and intracortical and striatal axonal arborizations were compared for two types of corticostriatal neurons in the medial agranular cortex of urethan-anesthetized rats: 1) pyramidal tract (PT) cells identified by antidromic activation from the medullary pyramid and 2) crossed corticostriatal (CST) neurons identified by antidromic activation from the contralateral neostriatum. The ipsilateral corticostriatal projections of intracellularly stained PT neurons as well as contralateral corticostriatal neurons were confirmed after labeling by intracellular injection of biocytin. 2. All well-stained PT neurons had intracortical and intrastriatal collaterals. The more common type (6 of 8) was a large, deep layer V neuron that had an extensive intracortical axon arborization but a limited axon arborization in the neostriatum. The less common type of PT neuron (2 of 8) was a medium-sized, superficial layer V neuron that had a limited intracortical axon arborization but a larger and more dense intrastriatal axonal arborization. Both subclasses of PT neurons had anatomic and physiological properties associated with slow PT cells in cats and monkeys and conduction velocities < 10 m/s. All of the PT cells but one were regular spiking cells. The exception cell fired intrinsic bursts. 3. Intracellularly stained CST neurons were located in the superficial half of layer V and the deep part of layer III. Their layer I apical dendrites were few and sparsely branched. Their axons gave rise to an extensive arbor of local axon collaterals that distributed in the region of the parent neuron, frequently extending throughout the more superficial layers, including layer I. Axon collaterals were also traced to the corpus callosum, as expected from their contralateral projections, and they contributed axon collaterals to the ipsilateral neostriatum. In the neostriatum, these axons formed extended arborizations sparsely occupying a large volume of striatal tissue. All CST neurons were regular spiking cells. 4. Both types of cells displayed spontaneous membrane fluctuations consisting of a polarized state (-60 to -90 mV) that was interrupted by 0.1- to 3.0-s periods of depolarization (-55 to -45 mV) accompanied by action potentials. The membrane potential was relatively constant in each state, and transitions between the depolarized and hyperpolarized states were sometimes periodic with a frequency of 0.3-1.5 Hz. A much faster (30-45 Hz) subthreshold oscillation of the membrane potential was observed only in the depolarized state and triggered action potentials that locked to the depolarizing peaks of this rhythm.(ABSTRACT TRUNCATED AT 400 WORDS)
Action Potentials↗
Mapping of fiber orientation in human internal capsule by means of polarized light and confocal scanning laser microscopy.
The nervous fibers in the human internal capsule were mapped according to their three-dimensional orientation. Four human cadaver brains were cut into comparable and standardized sections parallel to the ACPC-plane, stained with DiI, and analyzed using a combination of confocal and polarized light microscopy at the same time. This combination provides information about the structure and orientation of the fibers in great detail with confocal microscopy, and information about the localization and orientation of long myelinated fiber tracts with polarization microscopy. The internal capsule was parcellated in the areas CI 1 to CI 4 containing fibers of distinct orientation and structure, which enriches the macroscopically definable parcellation in the anterior and posterior limb. Fibers of the anterior thalamic peduncle intermingle with frontopontine tract fibers. Single fibers connect the caudate and the lentiform nucleus. The pyramidal tract is located in the anterior half of the posterior limb intermingled with fibers of the superior thalamic peduncle. Parietooccipitopontine fibers are located in the posterior part of the posterior limb. The slopes of the different systems of fibers change continuously in the anterior posterior direction of the internal capsule. Using the 3D orientation of fibers as a criterion for parcellation, as well as the description of bundles as a collection of fibers belonging to particular tracts leads to a more function-related description of the anatomy of the internal capsule. The method can be used for interindividual, sex- or age-related comparisons of particular systems of fibers.
Cadaver↗
Diffusion tensor imaging in presymptomatic and early Huntington's disease: Selective white matter pathology and its relationship to clinical measures.
Atrophy of cortical and subcortical gray matter is apparent in Huntington's disease (HD) before symptoms manifest. We hypothesized that the white matter (WM) connecting cortical and subcortical regions must also be affected early and that select clinical symptoms were related to systems degeneration. We used diffusion tensor magnetic resonance imaging (DTI) to examine the regional nature of WM abnormalities in early HD, including the preclinical period, and to determine whether regional changes correlated with clinical features. We studied individuals in early stages (HD), presymptomatic individuals known to carry the genetic mutation that causes HD (Pre-HD), and matched healthy controls. DTI indices of tissue integrity were obtained from several regions of interest, including the corpus callosum (CC), internal capsule (IC), and basal ganglia, were compared across groups by t tests, and were correlated to cognitive and clinical measures. WM alterations were found throughout the CC, in the anterior and posterior limbs of the IC, and in frontal subcortical WM in HD subjects, supporting the selective involvement of the pyramidal tracts in HD; a similar distribution of changes was seen in Pre-HD subjects, supporting presymptomatic alterations. There was a significant relationship between select DTI measures and cognitive performance. Alterations in diffusion indices were also seen in the striatum that were independent of atrophy. Our findings support that WM alterations occur very early in HD. The distribution of the changes suggests that these changes contribute to the disruption of pyramidal and extrapyramidal circuits and also support a role of compromised cortical circuitry in early cognitive and subtle motor impairment during the preclinical stages of HD.
Adult↗
The Babinski sign: the first hundred years.
The year 1996 marks the centenary of Babinski's description of the toe responses (normal and pathological) after stimulation of the sole of the foot. The upgoing toe response is normal in the 1st year of life and forms part of the flexion synergy of the leg, which had been known before 1896. Babinski also recognized the relation between the toe phenomenon (phénomène des orteils) in older children and adults and dysfunction of the pyramidal system. Neurologists became so fascinated by toe responses alone that many competing signs were proposed; most of these consisted of stimuli at other parts of the leg and were actually part of the same-but temporarily forgotten-flexion synergy. From 1910 to 1915 Marie and Foix and also Walshe re-emphasized this relationship and pointed out the analogy with the flexion reflex of the dog that had been extensively studied by Sherrington; the toe "extensors" shorten the leg and therefore they are flexors in a physiological sense. The normal (downward) toe response of the toes does not belong to a more complex movement, although Babinski originally believed this; it is a monosegmental skin reflex, akin to abdominal reflexes. Babinski correctly predicted that dysfunction of the pyramidal tract is not synonymous with a lesion, and that this dysfunction of the pyramidal system is necessary but not sufficient to produce a phénomène des orteils.
Eponyms↗
GAP-43 expression in the medulla of macaque monkeys: changes during postnatal development and the effects of early median nerve repair.
Expression of GAP-43, a neuronal specific growth associated phosphoprotein, has been highly correlated with the growth and remodeling of the nervous system during development and regeneration. As part of an effort to understand mechanisms of developmental plasticity in the somatosensory system, we determined how the expression of GAP-43 is affected by prenatal and early postnatal nerve cut and repair in macaque monkeys. We also observed normal developmental changes in the expression of GAP-43 during early postnatal life in macaque monkeys. The normal cuneate nucleus, as well as other nuclei of the ascending somatosensory pathways, had low levels of GAP-43 at birth that increased by 3 months and declined thereafter to reach adult levels between 8 and 15 months of age. Fiber tracts expressed low levels of GAP-43 at all postnatal ages, except the pyramidal tract which demonstrated high levels a birth that decreased over the first year. These observations suggest a gradual but differential synaptic maturation in lower brain stem nuclei as macaque monkeys mature. Greatly increased levels of GAP-43 were observed at the time of birth in the cuneate nucleus of two macaque monkeys with prenatal (E94 and El 14) nerve repair. Such an increase was not found after prenatal nerve repair with a postnatal survival time of 15 months, or after early postnatal nerve repair with short (80 days) or long (20 months) survivals. The results suggest that reorganization mechanisms at central terminals of peripheral nerves are very different following prenatal than postnatal nerve damage.
Animals↗
Carcinomatous encephalomyelopathy in conjunction with encephalomyeloradiculitis.
A man, aged 63, had an illness which lasted 11 months from onset with pain under the left costal margin which radiated to the epigastrium, until his death from cardiac failure. His symptoms consisted principally of parasthesias and proximal weakness of both upper and lower extremities with atrophy of the shoulder and pelvic girdles. He developed pyramidal tract signs, became euphoric, emotionally unstable and mentally retarded. There was no clinical evidence of cerebellar dysfunction. Bronchogenic carcinoma was suspected from a tomograph of the thorax, but, in spite of extensive clinical and laboratory studies, the diagnosis was verified only postmortem. The CSF cell count was high at first but diminished as the disease progressed. Muscle biopsies revealed chronic generalized denervation without signs of myopathy. Neuropathologically, encephalomyeloradiculoneuritis concentrated on the spinal cord was combined with severe rarefaction of the ganglion cells of the anterior horns and with bilateral degeneration of the lateral pyramidal spinocerebellar and posterior tracts. A more diffuse process was obvious in the anterolateral tracts of the lumbar region. Polyneuropathy concentrated in the distal region was accompanied by slight inflammatory reaction in the sciatic nerve. Cerebellocortical degeneration which exceeded physiological age-related rarefaction was also present. The findings are discussed in relation to the literature.
Carcinoma, Bronchogenic↗
MR imaging artifacts of the axial internal anatomy of the cervical spinal cord.
Transverse scans of the spinal cord routinely demonstrate signal variations related to the internal anatomy of the cord that do not accurately conform to histologic cross sections. This study evaluates the MR appearance of the axial anatomy of the spinal cord and provides correlation to histologic sections as a means to understand this discordance so that disease can be recognized more readily. Short TR/TE spin-echo studies, cardiac-gated multiecho spin-echo studies, and gradient-refocused-echo studies of normal excised human spinal cords, a normal volunteer, and gelatin phantoms were obtained by using the same imaging parameters at 1.5 T. Imaging artifacts were further investigated by using both a 128 x 256 and 256 x 256 matrix with a varying phase-encoded axis. Histologic sections of the excised cords, which were stained for myelin, iron, and cell bodies (Nissl), were used for correlation to the images. We found that significant Fourier truncation and partial-volume imaging artifacts modulated the MR display of the cord. On short TR/TE images a ring of high signal at the periphery of the cord was due to a truncation artifact. The appearance of the central portions of the gray and white matter was affected variably by partial-volume averaging depending on the matrix size. White-matter tracts of the cord were always lower in signal than was the gray matter on all pulse sequences. This finding was not due to iron deposition or CSF motion artifacts. We suspect that this probably was related to dense, longitudinal organization of spinal tracts and resultant anisotropy of water molecule motion similar to that seen in the pyramidal tracts, tendons, and ligaments. We recommend the use of a 128 x 256 matrix with two averages (four excitations) when obtaining axial scans of the spinal cord in living subjects. Although truncation artifacts diminish image quality, the quality is superior to that of images obtained with a 256 x 256 matrix, in which longer scanning times result in motion artifacts and reduced signal to noise.
Humans↗
Evoked potentials from direct cerebellar stimulation for monitoring of the rodent spinal cord.
Although the assessment of spinal cord function by electrophysiological techniques has become important in both clinical and research environments, current monitoring methods do not completely evaluate all tracts in the spinal cord. Somatosensory and motor evoked potentials primarily reflect dorsal column and pyramidal tract integrity, respectively, but do not directly assess the status of the ventral funiculus. The present study was undertaken to evaluate the use of evoked potentials, elicited by direct cerebellar stimulation, in monitoring the ventral component of the rodent spinal cord. Twenty-nine rats underwent epidural anodal stimulation directly over the cerebellar cortex, with recording of evoked responses from the lower thoracic spinal cord, both sciatic nerves, and/or both gastrocnemius muscles. Stimulation parameters were varied to establish normative characteristics. The pathways conducting these "posterior fossa evoked potentials" were determined after creation of various lesions of the cervical spinal cord. The evoked potential recorded from the thoracic spinal cord consisted of five positive (P1 to P5) and five negative (N1 to N5) peaks. The average conduction velocity (+/- standard deviation) of the earliest wave (P1) was 53 +/- 4 m/sec, with a latency of 1.24 +/- 0.10 msec. The other components followed within 4 msec from stimulus onset. Unilateral cerebellar stimulation resulted in bilateral sciatic nerve and gastrocnemius muscle responses; there were no significant differences (p greater than 0.05) in the thresholds, amplitudes, or latencies of these responses elicited by right- versus left-sided stimulation. Recordings performed following creation of selective lesions of the cervical cord indicated that the thoracic response was carried primarily in the ventral funiculus while the sciatic and gastrocnemius responses were mediated through the dorsal half of the spinal cord. It is concluded that the posterior fossa evoked potential has research value as a method of monitoring pathways within the ventral spinal cord of the rat, and should be useful in the study of spinal cord injury.
Animals↗
Long term post-traumatic retrograde corticospinal degeneration in man.
The spinal cord and brain of a man who died 18 years after a crush injury of lumbar segments contained some unusual lesions. There was a reduced number of myelinated axons in the corticospinal tracts as high as the fifth cervical segment. Such retrograde degeneration has been described in human pyramidal tracts only a few times. The results of reported studies of experimental retrograde degeneration have been inconsistent. The course of the fasciculus gracilis, as delineated by gliosis, was atypical, and an unusual glial nodule, possibly neoplastic, was present in the dorsal columns at C8.
Accidents, Traffic↗
The correspondence between Bernard Brouwer and John Fulton (1930-1940).
In 1933, Bernard Brouwer (1881-1949), first professor of neurology in Amsterdam (1923), made his second lecture tour in the USA. He met John Fulton (1899-1960) who had recently assumed the position of Sterling professor of physiology (1930). Next to clinical neurology, Brouwer had become well-known by his clinical-anatomical, experimental neuroanatomical, and comparative neuroanatomical work at the Central Institute for Brain Research in Amsterdam. At the time, John Fulton, pupil of Sherrington and Cushing, was particularly interested in research of the primate central nervous system. The correspondence between Brouwer and Fulton (1930-1940), preserved at the Manuscripts and Archives Division of Yale Library, provides an opportunity to study international exchange of neuroscientific knowledge in the first half of the 20th century. Brouwer and Fulton first met during the first International Congress of Neurology at Berne in 1931, where they discussed the anatomy of optic tracts. Next to this subject, the correspondence in that year dealt with the crossed and uncrossed pyramidal tracts. Brouwer's visit at Yale (1933) was well appreciated as appears from their correspondence as well as from Fulton's diary. Fulton sent several students to Amsterdam, including Margaret Kennard (1899-1976) who visited Amsterdam in order to "receive further neuroanatomical and clinical training of the type that only you can give". On the other hand, Brouwer sent several Amsterdam pupils and Dutch colleagues to New Haven. From the correspondence, we learn that there was a vivid exchange of neuroscientific knowledge by books, letters, reprints and pupils. The correspondence demonstrates the changing dynamics of scientific exchange between Europe and America.
Correspondence as Topic↗