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PubMed2006

White matter injury correlates with hypertonia in an animal model of cerebral palsy.

Hypertonia and postural deficits are observed in cerebral palsy and similar abnormalities are observed in postnatal rabbits after antenatal hypoxia-ischemia. To explain why some kits become hypertonic, we hypothesized that white matter injury was responsible for the hypertonia. We compared newborn kits at postnatal day 1 (P1) with and without hypertonia after in vivo global fetal hypoxia-ischemia in pregnant rabbits at 70% gestation. The aim was to examine white matter injury by diffusion tensor magnetic resonance imaging indices, including fractional anisotropy (FA). At P1, FA and area of white matter were significantly lower in corpus callosum, internal capsule, and corona radiata of the hypertonic kits (n=32) than that of controls (n=19) while nonhypertonic kits (n=20) were not different from controls. The decrease in FA correlated with decrease in area only in hypertonia. A threshold of FA combined with area identified only hypertonic kits. A reduction in volume and loss of phosphorylated neurofilaments in corpus callosum and internal capsule were observed on immunostaining. Concomitant hypertonia with ventriculomegaly resulted in a further decrease of FA from P1 to P5 while those without ventriculomegaly had a similar increase of FA as controls. Thus, hypertonia is associated with white matter injury, and a population of hypertonia can be identified by magnetic resonance imaging variables. The white matter injury manifests as a decrease in the number and density of fiber tracts causing the decrease in FA and volume. Furthermore, the dynamic response of FA may be a good indicator of the plasticity and repair of the postnatal developing brain.

Animals↗
PubMedDate not supplied

Pure motor hemiplegia: CT study of 30 cases.

Pure motor hemiplegia (PMH) is a well defined syndrome usually caused by ischemic lesions of lacunar type located either in the internal capsule or in the pons. Angiography and isotope scanning are usually normal. CT scan reveals small deep infarcts and appears to be the most reliable investigative method. The CT scan findings are described of thirty patients with PMH of rapid onset (less than 36 hours). In 29 of the 30 cases a lesion was found which could explain the PMH. Small hemorrhages (2 cm in diameter) in the posterior limb of the internal capsule were noted in two cases. Ischemic lesions were found in 27 patients, 22 patients had a single lesion (20 capsular and 2 pontine), while 5 patients had 2 lesions (2 bi-capsular, 3 capsular and pontine). Three varieties of ischemic capsular lesions were observed. We found in 15 cases a capsulo-putamine-caudate infarct (type I); in 8 cases a capsulo-pallidal infarct (type II); and in 2 cases an anterior capsulo-caudate infarct (type III). Type I corresponded to the area of the lateral lenticulostriate branches of the middle cerebral artery. Type II involved the territory of the perforating branches of the anterior choroidal artery. We suggest that type III involves the territory of the internal lenticulostriate branches of the anterior cerebral artery. Lacunes are generally linked to arterial systemic hypertension. However, only 16 of 30 patients in this series were chronically hypertensive.

Adolescent↗
PubMed1980

New phenotypic variant of adrenoleukodystrophy. Pathologic, ultrastructural, and biochemical study in two brothers.

Adrenoleukodystrophy is not usually considered in the differential diagnosis of the infantile onset of failure to thrive with motor and intellectual retardation. Rather, symptoms have started in childhood and have progressed over some years; not all patients have had overt adrenocortical insufficiency. The two brothers reported here developed symptoms in the neonatal period. In each the nature of the primary cerebral disorder was not recognized, because other etiologic factors clouded the diagnostic studies. In the younger brother, Case 1, a high titer (1:256) for cytomegalovirus (CMV) led to the suspicion that CMV infection accounted for the neurologic and ophthalmologic findings. Progressive neurologic deterioration at the age of 6 years prompted brain biopsy to confirm the diagnosis of progressive CMV encephalitis. In the older brother, Case 2, hemogenic hydrocephalus due to traumatic birth injury was held responsible for the psychomotor retardation and cerebral palsy. At necropsy, the adrenal glands in both cases were severly atrophic. In Case 1, a markedly inflammatory leukodystrophic process affected chiefly the frontal centra semiovalia and internal capsules, with relative sparing of parieto-occipital white matter and subcortical U-fibers. Heavy lymphocyte and monocyte cuffs surrounded many blood vessels in the white matter, and oil-red-O and PAS-positive macrophages were scattered in the zones of myelin disintegration and loss. Focally, the leukodystrophic process was so intense that cavitation necrosis was present, especially in the internal capsules. Further, PAS-positive, striated macrophages were aggregated in large clusters in liver, spleen, and lymph nodes. At the ultrastructural level, linear and gently arced, parallel, coapted or widely separated leaflets measuring 3-4 nm in width were identified in macrophages of the brain biopsy and in autopsy liver and lymph node. Biochemical analysis of fresh, frozen autopsy brain demonstrated cholesterol esters with long-chain fatty acids by thin-layer and gas-liquid chromatography. In Case 2, the leukodystrophic process could be readily identified in the brainstem and cerebellum but was masked in the cerebral hemispheres by the extensive hydrocephalus. The adrenal glands were atrophic and at light microscopy revealed adenomatoid nodules, many ballooned coritcal cells and very rare cells with striated cytoplasm. Masses of PAS-positive macrophages were encountered in liver and lymph nodes. In both cases, only old Wallerian degeneration of the corticospinal tracts was found in the spinal cord.

Adrenal Cortex↗
PubMed2003

Choreography of early thalamocortical development.

Thalamic axons, which carry most of the information from the sensory environment, are amongst the first projections to reach the cerebral cortex during embryonic development. It has been proposed that the scaffold of early generated cells in the ventral thalamus, internal capsule and preplate play a pivotal role in their deployment through sharp gene expression boundaries. These ideas were recently evaluated in various strains of mutant mice. In Tbr1, Gbx2, Pax6 KO both thalamic and corticofugal projections fail to traverse the striatocortical junction. In both Emx2 and Pax6 KO brains, the misrouted thalamic afferents are accompanied by displacements of the pioneering projections from the internal capsule. Regardless of their altered route, thalamic afferents in the reeler and L1 KO mice seem to be able to redistribute themselves on the cortical sheet and establish normal periphery-related representation in the somatosensory cortex. Early neural activity delivered through the thalamic projections is thought to be involved in the realignment process of thalamic axons at the time of their accumulation in the subplate layer. However, axonal growth and the early topographic arrangement of thalamocortical fiber pathways appear normal in the Snap25 KO, where action potential mediated synaptic vesicle release is disrupted. We therefore suggest that intercellular communication mediated by constitutive secretion of transmitters or growth factors might play a dominant role during early thalamocortical development.

Animals↗
PubMed1997

The side-effects and complications of posteroventral pallidotomy.

The side-effects and complications of posteroventral pallidotomy are analysed in 138 consecutive patients who underwent 152 pallidotomies. Transient side-effects, lasting less than three months, appeared in 18% of the patients, that is, 16.5% of the surgical procedures. Long term complications, lasting more than 6 months, were noted in 10% of the patients, that is, 9.2% of the surgical procedures. Sixteen complications occurred alone or in various combinations in 14 patients and included fatigue and sleepiness (2), worsening of memory (4), depression (1), aphonia (1), dysarthria (3), scotoma (1), slight facial and leg paresis (2) and delayed stroke (2). Complications such as dysarthria and paresis could be attributed to MR- or CT-verified pallidal lesions lying too medially and encroaching on the internal capsule. Two of the patients with deterioration in memory had some memory impairment before surgery, and the aphonic patient had dysphonia preoperatively. The study suggests that stereotactic MRI and careful impedance monitoring and macro-stimulation of the posteroventral pallidum area should be sufficient for minimizing the risk of complications; the stereotactic lesion should be centered within the posterior ventral pallidum without involvement of internal capsule. It is concluded that pallidotomy is a safe procedure if performed on cognitively alert patients, and it seems that both the incidence and especially the severity of complications are lower for posteroventral pallidotomy than for thalamotomy.

Adult↗
PubMed2001

Hypothalamic lesions in multiple sclerosis.

Demyelinating lesions of fiber bundles in and adjacent to the hypothalamus (i.e. the fornix. anterior commissure, internal capsule, and optic system) may be the basis for autonomic and endocrine alterations in multiple sclerosis (MS) patients. Therefore we investigated the presence and immunological activity of lesions in hypothalamic fiber bundles of 17 MS patients and 14 controls. In the MS group, 16 of 17 patients showed demyelinated lesions. The incidence of active lesions was high (60%) and outnumbered chronic inactive lesions in the internal capsule (p = 0.005). In 4 of 17 MS patients, axonal damage was observed and in 3 of 17 MS patients grey matter lesions were apparent. Duration of MS was inversely related to the active hypothalamic MS lesion score (r = -0.72, p = 0.001). Since comparison of hypothalamic lesions with MS lesions in other areas of the brain in the same patients (n = 7) showed a great similarity both as stage and appearance was concerned, this negative relation in all likelihood reflects the clinical consequences of high disease activity throughout the whole brain. In controls no demyelinating lesions were seen but in 11 control cases HLA expression was observed that was lower than that present in MS patients (p = 0.02). In the median eminence region that lacks a blood-brain barrier, all controls showed a strong HLA expression around the blood vessels. We conclude that systematic pathological investigation of the hypothalamus in MS patients reveals an unexpected high incidence of active lesions that may impact on hypothalamic functioning.

Adult↗
PubMed1993

[Angiotropic lymphoma presenting with subacute dementia: treatment with combination chemotherapy (CHOP) based on antemortem diagnosis--a case report].

We report a 64-year-old male with angiotropic lymphoma. He developed subacute dementia with right hemiparesis. Laboratory abnormalities included elevated serum lactic dehydrogenase (LDH) (715 U/l) erythrocyte sedimentation rate (38 mm/hr) and CSF protein (90 mg/dl). Precontrast MR imaging of the brain demonstrated lesions involving the left internal capsule, subcortical white matter in the right frontal lobe and splenium within the atrophic corpus callosum. A brain biopsy revealed intravascular lymphoid cells, strongly suggestive of angiotropic lymphoma. By combination chemotherapy (CHOP), serum LDH and CSF protein normalized through the patient remained demented. He died of bronchopneumonia about 2 years and 5 months after the onset. Coronal sections of the brain showed infarct in the left internal capsule as well as markedly thin corpus callosum with necrotic lesions involving both the genu and splenium. Microscopic examination showed many small vessels occluded by lymphoma cells (B-lymphocyte) predominantly in the corpus callosum, cerebral white matter, thalamus, midbrain, medulla oblongata, thoracic and lumbar segments of the spinal cord. By combination chemotherapy, our patient survived longer than most of previous patients with angiotropic lymphoma. An early diagnosis and subsequent combination chemotherapy may improve neurological manifestations, and make possible longer survival in angiotropic lymphoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

The origin, course, and termination of the hippocampothalamic projections in the macaque.

The projections from the hippocampal formation to the thalamus were investigated with both anterograde and retrograde tracers. Horseradish peroxidase was injected into medial and midline thalamic sites in six cases, and tritiated amino acids were injected into the hippocampal formation in nine others, five of which had prior transections of the fornix. Only the subicular and entorhinal cortices were found to project to the thalamus. From the subicular cortex, dense bilateral projections were traced through the fornix to the anterior nuclei, while lighter fornical projections terminated in other rostral midline sites, including the nuclei reuniens, centralis latocellularis, and paraventricularis. These projections arose predominantly from the polymorphic cells which are located in the deepest cellular layers of the subiculum and prosubiculum. In addition, the subicular cortex was found to project to the nucleus lateralis dorsalis. The latter projection, which showed evidence of a crude topographic organization, ran either through the fornix or, unlike the other subicular efferents, through the sublenticular limb of the internal capsule to form part of the temporopulvinar bundle of Arnold. The nonfornical projection to the nucleus lateralis dorsalis passed through the medial pulvinar, where there was some additional termination. Few, if any, projections from the entorhinal cortex to the thalamus travelled in the fornix. Rather, the entorhinal efferents were carried in the inferior thalamic peduncle to the magnocellular portion of the nucleus medialis dorsalis, and in the internal capsule and bundle of Arnold to the medial pulvinar and the nucleus lateralis dorsalis.

Afferent Pathways↗
PubMed1997

Maturation of neuronal form and function in a mouse thalamo-cortical circuit.

Postnatal development of physiological properties underlying slow intrathalamic oscillations was studied by whole-cell recording from synaptically coupled neurons of the reticular nucleus (RTN) and ventral posterior nucleus (VPN) of mouse brain slices in vitro and compared with the morphological development of dye-injected cells. Between postnatal days 3 and 11 (P3-P11), progressive changes in RTN and VPN neurons included shortening of the membrane time constant, decreasing input resistance, and lowering of the resting membrane potential (RMP). Low-threshold Ca2+ spikes (LTS) were present from P3, but their capacity to sustain multispike bursts was limited before P11. Synaptic responses were evoked in RTN and VPN neurons by electrical stimulation of the internal capsule from P3. Younger RTN neurons responded with a single spike, but their capacity to fire bursts gradually improved as the RMP reached levels below the LTS activation potential. Concomitantly, as the reversal potential of the inhibitory postsynaptic potential in VPN neurons became more negative, its capacity to deinactivate the LTS increased, and rebound bursts that could maintain oscillations were produced; sustained oscillations became the typical response to internal capsule stimulation at P12. The functional maturation of the intrathalamic circuitry, particularly between P10 and P14, occurs in parallel with the morphological maturation (size, dendritic growth, and dendritic field structure) of individual RTN and VPN neurons, as studied by confocal microscopy. Maturation of RTN cells led that of VPN cells by 2-3 d. The appearance of intrathalamic oscillations is probably correlated with the appearance of slow-wave sleep in postnatal animals.

Aging↗
PubMed1989

Detection of lacunar infarction in brain CT-scans: no evidence of bias from accompanying patient information.

Interobserver agreement in assessing brain CT-scans is, in general, high. The extent, however, to which such agreement is caused by bias through knowledge of other clinical details remains uncertain. The hypothesis that observers are somehow prejudiced before assessing ambiguous CT-scans in this particular situation was tested. Sixteen neurologists and 16 radiologists volunteered to interpret two ambiguous brain CT-scans, with regard to the presence or absence of a lacunar infarct in the region of the internal capsule. The scans were accompanied by "patient" information that was or was not suggestive of a stroke. These scans were camouflaged by a variety of other scans, to be assessed in the same way, to mask the purpose of the study. It was assumed that the observers, in their assessments of the scans, would somehow let their ratings of the likelihood of a lacunar infarction in or near the internal capsule be subject to the accompanying information. Results showed lower ratings produced by neurologists (i.e., less likelihood of an infarction) than by radiologists in the majority of all assessments, but no bias by the accompanying information.

Cerebral Infarction↗
PubMed1997

Complexities in the thalamocortical and corticothalamic pathways.

It is now a century since Kölliker (Handbuch der Gewebelehre des Menschen. Nervensystemen des Menschen und der Thiere, Vol. 2, 6th edn. Engelmann, Leipzig, 1896) described the thalamic reticular nucleus as the 'Gitterkern' or lattice nucleus on the basis of the fibrous latticework that is the characteristic feature of this part of the ventral thalamus and adjacent parts of the internal capsule. We suggest that the fibre reorganization produced in this lattice is a fundamental requirement for linking orderly maps in the thalamus to corresponding cortical maps by two-way thalamocortical and corticothalamic connections; these connections involve divergence, convergence and mirror reversals, which all have to occur between the thalamus and the cortex. Apart from the thalamic reticular nucleus, two transient groups of cells, the perireticular nucleus (located in the internal capsule lateral to the reticular nucleus) and the cells of the cortical subplate, are prominent along the course of axons linking the cortex and thalamus early in development. The functions of these two cell groups are not known. However, since early in development complex patterns of reorganization, defasciculation and crossings occur in the regions of these cells, it is likely that they play a role in creating the latticework of the adult. The latticework that characterizes the thalamic reticular nucleus of mammals can also be identified in the ventral thalamus of non-mammalian brains, formed along the course of the fibres that join the dorsal thalamus to the telencephalon. We suggest that the ubiquitous presence of such a zone of fibre reorganization is integral to the functioning of the thalamocortical pathways, and that the complexity of thalamic connections produced in the lattice has been central to the evolutionary success of the thalamotelencephalic system.

Animals↗
PubMed1998

Gradient of microglial activation in the brain of SIV infected macaques.

Brains of macaques inoculated with macrophage-tropic, neurovirulent virus 7F, with lymphocyte-tropic SIV mac239, or with dual-tropic SIVmac239/1yE, were examined for microglial activation, astrocyte activation, apoptosis and neuron loss. The brain one animal inoculated with neurovirulent virus 7f showed massive microglial activation as assessed by expression of the major histo-compatibility complex class II (MHC-II). In this animal very numerous, large microglial nodules expressing MHC-II were concentrated in the basal pons and internal capsule. These microglial nodules contained cells undergoing apoptosis detected by in situ end labeling of fragmented DNA. In this animal, neuron loss was apparent near the microglial nodules. In the animals inoculated with SIVmac239 or SIVmac239/17E, pathologic changes such as perivascular cuffing and formation of microglial nodules were absent. However, increased expression of MHC-11 by microglial cells was also concentrated in white matter of the basal pons, midbrain and internal capsule. These results indicate the microglial activation in SIV-infected macaques follows a ventral to dorsal gradient regardless of viral tropism. These results also show that the type and severity of neuropathological changes in SIV-infected macaques is highly dependent on the tropism of the inoculated virus.

Animals↗
PubMed1997

Topography of fibre organisation in the corticofugal pathways of rats.

The organisation of the long descending corticofugal pathways is poorly understood. We have examined these pathways to determine the fibre relationships along the extent of their course through the internal capsule, cerebral peduncle, longitudinal pontine fasciculus, pyramid, pyramidal decussation, and dorsal column of the spinal cord. Different cytoarchitectonic regions (e.g., lateral agranular and granular) of the rat's neocortex were injected with the axonal tracer biotinylated dextran. In other experiments, each animal had different-coloured fluorescent tracers (Fluoro Ruby and dextran-fluorescein) injected into separate cortical areas. Our results show that in the anterior and posterior limbs of the internal capsule, axons arising from spatially separate sites in rat neocortex occupy distinct regions of the cross-sectional area of the pathway. More caudally, within the cerebral peduncle and the longitudinal pontine fasciculus, axons from more distant cortical areas remain largely separate, but those from adjacent cortical areas begin to overlap. By the medullary pyramid, the pyramidal decussation, and the dorsal column of the spinal cord, the representations of all the cortical regions injected overlap completely; in these structures, the axons arising from each cortical area are widely intermingled. Thus, along the rostral-to-caudal course of the corticofugal pathways, there is a change in the organisation of axons. At rostral levels, the order corresponds roughly to the spatial distribution of the cells of origin, but more caudally, this changes to an arrangement of axons that has no readily apparent order. A similar change has been observed along the course of the retinofugal pathway, where a decrease of spatial order in the fibre distribution has been associated with a reordering of axons according to their temporal sequence of outgrowth.

Animals↗
PubMed1994

The somatotopic localisation of the descending cortical tract in the cerebral peduncle: a study using MRI of changes following Wallerian degeneration in the cerebral peduncle after a supratentorial vascular lesion.

We studied the effects of Wallerian degeneration in the cerebral peduncle shown by magnetic resonance imaging (MRI) following a supratentorial vascular lesion, to identify the somatotopic localisation of the descending cortical tracts. Patients with a lesion involving a large area of a cerebral hemisphere had an area of abnormal signal intensity in the whole cerebral peduncle, suggesting Wallerian degeneration of all the whole descending cortical tracts. With a small lesion confined to the precentral gyrus, corona radiata, or posterior limb of the internal capsule there was an abnormal signal at the centre of the peduncle, suggesting degeneration of the precentrospinal tract. Those with a small lesion confined to the paracentral gyrus had an abnormal area slightly lateral to the centre of the peduncle, suggesting degeneration of the parietospinal tract. Patients with a lesion of the parietal or temporal lobes, not including the paracentral or precentral gyri, corona radiata, or the posterior limb of the internal capsule, had an abnormal area laterally in the peduncle, suggesting degeneration of the parietopontine or temporopontine tract.

Adult↗
PubMed2000

[A patient with choreoathetosis of the left upper extremity due to acute cerebral infarction].

A 71-year-old woman was admitted to our hospital because of involuntary movement of the left upper extremity. MR image of the brain 15 days after the onset revealed the low intensity in right posterior limb of internal capsule. The lesion was surrounded by thalamus, subthalamic nucleus, and globus pallidus with enhancement by Gd-DTPA. Surface EMG revealed irregular grouped discharge in short duration and grouped discharge in long duration in the left upper extremity. Those features are compatible with one of choreoathetosis. Choreoathetosis due to cerebral infarction in acute phase is rare. We discussed pathophysiology of this involuntary movement due to lacunar infarction of posterior limb of internal capsule in acute phase.

Aged↗
PubMedDate not supplied

[Volumetric relationships of the rat striatum and its traversing corticofugal and corticopetal pathways].

On histological slices, studies have been made on the striatal area and total area of the internal capsule bundles passing through the striatum. The predominant diameter of fiber bundles which pass via the striatum and form direct contacts with the callosal body is equal to 10-60 micrometers, their total number being equal approximately to 1,320. Average area occupied by the bundles at all levels of the striatum on frontal slices amounts of 30.7%. It means that about 1/3 of the striatal volume is formed by the internal capsule bundles, whereas 2/3 of its bulk are occupied by neurones.

Afferent Pathways↗
PubMed1994

[Somatosensory evoked potentials in vascular damage to central sensory pathways].

Somatosensory evoked potentials from median nerve (SEP-M) were examined bilaterally in 43 patients with a well delimited vascular foci in central somatosensory pathways. Scalp, far field, cervical, Erb potentials and conduction times were recorded in each patients. Five subgroups based on localization of foci (parietal cortex, corona radiata, internal capsule, thalamus and extensive subcortical--cortical hemispheric focus) were distinguished. The results from the unimpaired (n-38) and impaired (n-48) sides, focus subgroups and control healthy group were statistically compared. The attempt to establish a specific relationship between the SEP-M picture and site of the lesion gave a negative result. SEP-M changes were more pronounced in cases of very extensive axons run in a compact bundle (internal capsule). The SEP-M examination indicates only the degree of the central sensory system damage. Correlations between intensity SEP-M pathology and clinical sensory disturbances were found. SEP-M parameters on the unimpaired side differed significantly from those of the control group. Therefore the impaired side should not be used as a reference for evaluation of impaired side pathology. The diagnostic validity of far field potentials recordings in such investigations is stressed.

Adult↗
PubMed1991

[Quantification of wallerian degeneration of the pyramidal tract in the capsular region by magnetic resonance imaging].

Using magnetic resonance imaging, we studied 23 patients with motor deficit associated with cerebrovascular disease of the internal capsule. According to the severity of the motor deficits, 23 patients were divided into three groups (severe group...9, moderately severe group...8, mild group...6). A coronal T2-weighted image was obtained along a straight line between the front edge of the medulla and the deepest point of the interpeduncular cistern in a midsagittal T1-weighted image. It was revealed that wallerian degeneration extended continuously from part of the internal capsule down to the pons or medulla or the decussation in all patients. The area of wallerian degeneration in the pons and the area of half the pons were calculated from the coronal T2-weighted image. Moreover, the wallerian index was calculated as: (area of wallerian degeneration in pons divided by area of half the pons) X 100. Values of the wallerian index +/- SD were 26.4 +/- 5.1 in the severe group, 19.2 +/- 5.6 in the moderately severe group, and 10.0 +/- 5.4 in the mild group. There were significant differences among the three groups. We concluded that the area of wallerian degeneration was related to the severity of motor deficits.

Adult↗