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PubMed1985

Longitudinal topography and interdigitation of corticostriatal projections in the rhesus monkey.

Anterograde tracing methods were used to examine the topographic organization and interrelationship of projections to the neostriatum arising from various areas of association cortex. In contrast to the currently accepted topographic schema, all cortical areas examined project to longitudinal territories that occupy restricted medial-lateral domains of the neostriatum. The posterior parietal and superior arcuate cortices project to dorsolateral portions of the neostriatum; the dorsolateral and dorsomedial frontal cortices project centrally; and the orbitofrontal, anterior cingulate, and superior temporal projections are distributed to ventromedial regions of the caudate nucleus and putamen. In coronal section, cortical terminal fields form a diagonal strip, extending from the dorsal, ventricular border of the caudate nucleus, through the fiber bundles of the internal capsule, to the ventral margin of the putamen. Double labeling studies, in which two cortical areas were injected in the same animal, indicated that convergence of input within neostriatal domains is not governed by reciprocity of corticocortical connectivity. Thus, the interrelationship of projections arising from connectionally linked cortical areas ranged from nearly complete segregation of terminal fields (e.g., from dorsolateral prefrontal and orbital cortices) to extensive overlap of terminal domains (e.g., from frontal and temporal cortices). In the latter case, detailed analysis revealed that frontal and temporal terminals actually were interdigitated rather than intermixed within the zone of overlap. The present findings suggest a new conceptualization of corticostriatal topography in the primate which emphasizes the longitudinal arrangement of cortical terminal domains. Additionally, these findings provide a map for functional parcellation of the neostriatum on the basis of its cortical innervation which may prove useful to understanding normal striatal function, as well as the symptomatology associated with neostriatal injury and disease.

Animals↗
PubMed1985

Morphological and functional types of neurons in cat ventral posterior thalamic nucleus.

Neurons in the thalamic ventral posterior (VB) nucleus of the cat were investigated by extracellular and intracellular recording and by anatomical methods involving either the retrograde transport of horseradish peroxidase (HRP) or the intracellular injection of HRP. Two morphological types of neurons could be detected by retrograde labeling from small injections of HRP in the internal capsule adjacent to VB. These two and one other type, judged to be an interneuron, could also be identified by intracellular staining. Type I cells are large, have thick proximal dendrites which branch in a tuft-like manner, and thick, rapidly conducting axons. They possess few or no dendritic appendages. Type II cells are smaller and have slender proximal dendrites which branch dichotomously and thin, slower conducting axons. Those injected intracellularly are covered in fine, hair-like dendritic appendages. Type III cells are small and have thin processes that give rise to many bulbous dilatations and no obvious axon. Type I and type II cells give off slender axon collaterals in the thalamic reticular nucleus but not in VB. Examples of both types of cell could be antidromically activated from the somatic sensory cortex. Type I and type II cells recovered histologically after intracellular recording included examples of most types of receptive field, including several forms of cutaneous and deep fields, as classified by us in a parallel intra- and extracellular study of unit responses. All but one type I cell, however, responded in a transient manner to peripheral stimulation. The remaining type I cell and all members of an admittedly small sample of type II cells responded in a sustained manner. The sample of recovered interneurons and of units that could not be driven antidromically from the cerebral cortex suggested that they, too, included all receptive field types. We conclude that submodality specificity in VB is not represented by morphological specificity in thalamocortical relay cells or interneurons. Some other functional parameter, such as tonic or phasic responsiveness, may be more obviously correlated with relay cell morphology.

Action Potentials↗
PubMed1986

Spindle activity in the waking electroencephalogram: report of a case with hemispheric glioblastoma.

In this paper, we reported a patient with a hemispheric glioblastoma extending into the lateral thalamus and the posterior limb of the internal capsule. The waking electroencephalogram showed spindle activity on the side ipsilateral to the tumor. Based on the topography of the tumor in our patient, we speculate that a disruption of the synaptic pathways within the thalamus-cortex-thalamus circuit was primarily involved in the pathogenesis of abnormal spindling.

Aged↗
PubMed1977

Ascending projections of the locus coeruleus in the rat. II. Autoradiographic study.

The ascending projections of the locus coeruleus were studied using an autoradiographic method. The major projection of locus coeruleus neurons ascends in a dorsal pathway traversing the midbrain tegmentum in a position ventrolateral to the periaqueductal gray. At the caudal diencephalon the locus coeruleus axons descend to enter the medial forebrain bundle at a caudal tuberal hypothalamic level. They are jointed in the medial forebrain bundle by a much smaller locus coeruleus projection which takes a ventral course through the midbrain tegmentum and enters the medial forebrain bundle via the mammillary peduncle and ventral tegmental area. Terminal projections are evident in the midbrain to the periaqueductal gray, tegmentum and raphe nuclei. There are widespread projections to the dorsal thalamus. The heaviest of these are to the intralaminar nuclei, the anteroventral and anteromedial nuclei, the dorsal lateral geniculate and the paraventricular nucleus. In the hypothalamus the largest projections are to the lateral hypothalamic area, periventricular nucleus, supraoptic nucleus and paraventricular nucleus. As the locus coeruleus projection ascends in the medial forebrain bundle, fibers leave it to traverse the lateral hypothalamus and zona incerta and enter the internal capsule, the ventral amygdaloid bundle and ansa peduncularis. These appear to terminate in the amygdaloid complex and, via the external capsule, in the lateral and dorsal neocortex. At the level of the septum 4 projections are evident. One group of fibers enters the stria medullaris to terminate in the paraventricular nucleus and habenular nuclei. A second group joins the stria terminalis to terminate in the anygdaloid complex. The third group turns into the diagonal band and medial septum; some fibers terminate in the septal nuclei and others continue into the fornix to termimate in hippocampus. A large component continues around the corpus callosum into the cingulum to terminate in the cingulate and adjacent neocortex, the subiculum and hippocampus. The remaining fibers continue rostrally in the medial forebrain bundle to terminate in olfactory forebrain and frontal neocortex. Commissural projections arise at 4 locations. The first decussation occurs in the dorsal tegmentum just below the central gray rostral to the locus coeruleus. The crossing fibers enter the contralateral dorsal bundle. A second group of fibers leaves the ipsilateral dorsal pathway, crosses in the posterior commissure and enters the contralateral dorsal pathway at the level. The third commissural projection arises more rostrally and crosses in the dorsal supraoptic commissure to enter the contralateral medial forebrain bundle. The fourth commissural projection is through the anterior commissure. The termination of the contralateral projection appears similar to that of the ipsilateral projection.

Afferent Pathways↗
PubMed1988

Neoplastic angioendotheliomatosis in a dog: an angiotropic lymphoma.

Neoplastic angioendotheliomatosis was diagnosed in a nine-year-old, intact male German Shorthaired Pointer exhibiting progressive neurological signs over a six-month period. At necropsy, there was multifocal asymmetric, hemorrhagic necrosis within the cerebral hemispheres, centrum semiovale, caudate nucleus, and internal capsule. Histologically, there was extensive intravascular proliferation of pleomorphic mononuclear cells within the brain and multiple parenchymatous organs. Transmission electron microscopy demonstrated the absence of intercellular junctions between neoplastic cells. These cells were not attached to the vascular lining endothelium; Weibel-Palade bodies and a basement membrane were lacking. By indirect immunofluorescence, positive cytoplasmic staining of intravascular neoplastic cells for IgG was demonstrated. Peroxidase-antiperoxidase technique for Factor VIII related antigen was negative. As in man, this rare neoplastic disorder appears to be a lymphoma, apparently of the B cell line.

Animals↗
PubMedDate not supplied

MRI of normal brain maturation.

The unprecedented gray/white differentiation obtained with magnetic resonance imaging (MRI) has created a unique opportunity to trace the normal process of myelination. Fifty-nine children referred for evaluation of a nonneurologic problem or a nonspecific neurologic complaint were studied with MRI using spin-echo technique. Children ranged in age from term (40 weeks intrauterine) to 16 years. Scans were reviewed for quantitative and qualitative changes with age. T1 and T2 relaxation times were measured for 13 regions of interest in 37 children. With increasing age a sharp decrease in both T1 and T2 values, most pronounced during the first year of life, was seen. The prolonged relaxation times in the newborn infant correspond to the known high water content of the neonatal brain; the subsequent decline corresponds to the decrease in water content and increase in myelination observed in autopsy studies of infants. Qualitative changes in the MRI appearance of the brain with age using a spin-echo sequence (2 sec repetition time) demonstrated that the process of myelination was most rapid during the first 2-3 years of life. Myelination appeared to occur earliest in the posterior fossa, with the middle cerebellar peduncle identifiable at only 3 months. By the age of 1 year, all major white matter tracts including the corpus callosum, subcortical white matter, and the internal capsule were well defined. However, due to subtle changes in appearance, the refined configuration of the adult brain was not attained until early adolescence.

Adolescent↗
PubMed1986

[Cortical SEP of early and intermediate latency following stimulation of the median and tibial nerves in disseminated encephalomyelitis--relation to findings in cerebral nuclear magnetic resonance tomography].

Cortical somatosensory evoked potentials following median and tibial nerve stimulation were compared with the findings in nuclear magnetic resonance imaging in 23 patients with multiple sclerosis, 11 of whom presented with their first disease manifestation. Pathological SEP's were found in 55 percent of patients presenting with first manifestation and in 83 percent of those with a longer duration of illness. Except for one patient with spinal cord involvement only, in whom no cerebral lesions were seen, all patients showed periventricular lesions in NMR. Between 1 and 16 (4.7 +/- 3.5) non-periventricular isolated lesions were found per patient. Cortical SEP's are affected differently by lesions within the thalamocortical system: Plaques within the internal capsule may result in SEP-changes as seen in other causes of damage to this region. However, lesions in this strategic area may also remain clinically and electrophysiologically silent. Nevertheless, the size of the lesion seen in NMR is not relevant, as observed in one case of an extensive plaque within the centrum semiovale. Correlations between the lesions near the parietal cortex or within the parietal white matter and SEP-component alterations of intermediate latency (N55, N75) remained insignificant.

Adult↗
PubMedDate not supplied

CT of subinsular infarction and ischemia.

A number of CT head scans, covering a 2-year period and showing a variety of distinct curvilinear subinsular lucent lesions, were collected and reviewed. Variations in extent of involvement, tendency toward bilateral symmetry, and clinical background allowed the lesions to be grouped into four general patterns, most of which, to our knowledge, have not been specifically described in the radiologic literature. This project was undertaken first to bring to the attention of those involved in interpretation of cranial CT images several patterns of injury they may not heretofore have been aware of and second to attempt to derive a specific etiology for each of the patterns described. Pattern 1, which appears as a distinct curvilinear lesion (sometimes cystic) apparently limited to the lateral aspect of the putamen, is thought to represent the residua of previous lateral striatal hemorrhage. Pattern 2, occurring in a markedly younger age group appears as relatively symmetrical bilateral subinsular lucencies, which in one case completely resolved. A specific etiology for this pattern remains uncertain. Acute demyelination, either secondary to a variant of anoxic leukoencephalopathy or to a limited form of diffuse encephalomyelitis, is postulated. A third pattern, which extends from generalized deep frontal white-matter lucency across the anterior limb of the internal capsule and tapering posteriorly in the subinsular area is thought to be on the basis of chronic ischemia similar to subcortical arteriosclerotic encephalopathy. The fourth pattern, occurring as a broad band of lucency extending from the frontal horn of the lateral ventricle and also tapering posteriorly is due to relatively proximal occlusion of the lateral lenticulostriate arteries.

Adolescent↗
PubMedDate not supplied

MR imaging of optic pathways in patients with neurofibromatosis.

Twenty-one patients with documented neurofibromatosis had MR examinations to evaluate possible intracranial disease. In five cases the indication was a known or suspected optic glioma. Two patients were examined because of a history of seizures; the rest were examined as part of a baseline evaluation. Eighteen patients showed evidence of signal hyperintensity on T2-weighted images. Lesions involved the optic nerves, optic chiasm, optic tracts, lateral geniculate body, optic radiations, basal ganglia, periventricular white matter, cerebellar white matter, and dentate nucleus of the cerebellum. Comparison between MR and concurrent CT scans showed MR to be superior in demonstrating the posterior extent of optic-pathway gliomas. In addition, MR showed focal areas of hyperintensity in the basal ganglia, internal capsule, cerebellum, and/or white matter that were not detected on CT. Although we found MR to be superior to CT in detecting intracranial tumors in patients with neurofibromatosis, and in evaluating the extensive involvement of known lesions, the full clinical implications of our findings remain to be determined.

Adolescent↗
PubMedDate not supplied

MR imaging of compact white matter pathways.

A prominent decreased signal intensity can be seen in many of the heavily myelinated, compact fiber pathways of the brain on T2-weighted spin-echo MR images (TR = 2500 msec, TE = 80 msec). These areas include the anterior commissure, internal capsule, optic tract and radiations, fornix, mammillothalamic tract, superior frontooccipital fasciculus, cingulum, corpus callosum, uncinate fasciculus, and superior longitudinal fasciculus. All these pathways could be identified in normal subjects 3 years old and older when 1.5-T axial and coronal images of 50 adults and 17 children were reviewed. Correlation of the in vivo and postmortem MR appearance of two human brains with Perls and Luxol fast blue stains indicates that the short T2 reflects heavy myelination and fiber density, not iron deposition. This is in contrast to the short T2 signal seen in the subcortical U fibers and deep nuclei of the brain that result from iron deposition. These pathways also differ from areas of brain iron accumulation in that (1) they may appear as areas of short T1 on partial-saturation or inversion-recovery pulse sequences and (2) they can be seen with regularity in all patients over 3 years of age. It is important to distinguish between the effect of the myelin sheath and the effect of brain iron on the T2 relaxation values seen in the normal brain since both result in shortened T2 relaxation. The importance of the role of these fiber tracts in disease processes and in modifying the spread of vasogenic edema and tumor needs further investigation.

Adolescent↗
PubMed1985

[The anterior choroidal artery syndrome].

The anterior choroidal artery syndrome is extremely rare. When complete, it includes hemiplegia, hemianaesthesia and homonymous lateral hemianopsia. The diagnosis is provided by computerized tomography which shows a low-density area located in the posterior part of the posterior limb of the internal capsule, sparing the thalamus medially but involving the tip of the pallidum externally and corresponding to the territory of the anterior choroidal artery. Incomplete forms of the syndrome have been described. The syndrome may also be associated with neuropsychological disorders, including left neglect syndrome in right-sided lesions and disorders of speech in left-sided lesions. The anatomico-clinical correlations are discussed.

Arteries↗
PubMed1988

A unique membrane protein is expressed on early developing limbic system axons and cortical targets.

The limbic system-associated membrane protein (LAMP) is a 64 kDa protein that, in the adult brain, is present in cortical and subcortical regions comprising the limbic system (Levitt, 1984). The developmental expression of LAMP was studied in fetal rat brains to determine the specific patterns of distribution and the cellular elements that exhibit LAMP immunoreactivity. Light microscopic immunocytochemical analysis revealed that LAMP is expressed on neurons and their growing axons early in fetal development, at a time coincident with pathway formation and differentiation of limbic system nuclei. In the forebrain, where limbic system structures are heavily concentrated, immunoreactivity appears on subpopulations of axons in a temporal sequence that correlates with the time of formation of pathways carrying limbic system axons. Thus, staining is evident first at embryonic day (E) 15 on fibers within the internal capsule coursing from the diencephalon to cortex. LAMP immunoreactivity appears over the next 3 d in the anterior commissure, fornix, and corpus callosum. Ultrastructural immunocytochemical analysis reveals dense surface staining of fascicles of developing axons and growth cones. The axonal staining is transient, disappearing during the second postnatal week of development. In cerebral cortex, cells in presumptive limbic cortical regions such as lateral perirhinal sulcal cortex and prefrontal cortex are LAMP immunoreactive from the inception of the cortical plate. These cortical regions are clearly delineated from surrounding unstained nonlimbic areas as early as E15. Thus, LAMP expression in the cortex may represent one of the earliest markers of specific cytoarchitectonic areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

[Cerebral ischemia (1)--Reversibility of ischemic lesion and CT findings].

Two hundred and twenty-one patients with cerebral cerebral ischemic attack in the middle cerebral artery territory were investigated. Those patients manifested several clinical types, TIA: 31, stroke with full recovery: 50, minor completed stroke: 54 and major completed stroke: 86 cases. CT classification was made 3 weeks after the ischemic attack based on the characteristic arterial topography. We discussed in this paper what kind of ischemic lesion had greater possibility of recovery from ischemic lesion had greater possibility of recovery from ischemia focusing on the retrospective study of clinical symptoms, CT classification and angiographic findings. We also referred to the other factors influencing the reversibility of an ischemia such as lacunae and PVH (periventricular hypodensity). The extent of and LDA on CT scan closely correlated with clinical symptoms, CT classification and angiographic findings. We also referred to the other factors influencing the reversibility of an ischemia such as lacunae and PVH (periventricular hypodensity). The extent of an LDA on CT scan closely correlated with clinical types (Table 2). The reversibility of type I was excellent, however aged patients over 70 with PVH and ventricular dilatation developed permanent neurological impairment associated with dementia. The reversibility of a small infarction in the basal ganglia (type II) depended mainly on the involvement of the internal capsule. Infarction involving a cortex (type IV and type V) invariably resulted in permanent neurological deficits except for the rare cases with involvement of silent areas. CT classification of type III, so called demarcation zone infarction, developed various clinical types, and showed transient functional disturbance of the cortex without an infarction i the cortico-subcortical region.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Leucodystrophy with pigmented glial and scavenger cells (pigmentary type of orthochromatic leucodystrophy).

A 38-year-old man with progressive psychiatric disturbances, dysarthria, myoclonus, rigidity and terminal generalized seizures died 4 years after onset. At post-mortem, severe leucodystrophy of the centrum semi-ovale, corpus callosum and internal capsule was found. In the demyelinated areas, abundant mononuclear phagocytes were found filled with dark yellow or brown pigment granules, staining with PAS and Sudan black, autofluorescent in paraffin sections, and orthochromatic with toluidine blue in paraffin and frozen sections and positive with Fontana's silver method. Iron deposits were present in a few cells. Electron micrographs of a biopsy showed massive storage of lipofuscin and ceroid with fingerprint profiles in macrophages and, to a lesser degree, in astrocytes as well. Oligodendroglia were depleted in demyelinated areas but prominent in the subcortical regions and in small foci in the deep cerebral white matter; they contained intracytoplasmic inclusions with fingerprint profiles. From these morphological findings it is suggested that lipofuscin and ceroids are the lipopigments stored in the pigmentary type of orthochromatic leucodystrophy.

Adult↗
PubMed1987

[An autopsy case of multicentric glioma of multiple histopathology].

An autopsy case is described of an 66-year-old man with multicentric glioma of multiple histopathology, i.e. protoplasmic astrocytoma and glioblastoma. Enhanced CT scan revealed three separate lesions in the right cerebral hemisphere, pons, and cerebellar vermis. Initial diagnosis by CT included metastatic and primary brain tumor, multiple abscess, fungal infection, parasites, tuberculoma, and so on. Biopsy of the right frontal mass revealed astrocytoma grade-2. An autopsy revealed gelatinous, clear marginal mass in the right frontal, parietooccipital and cerebellar vermis; an opaque marginal mass with necrosis in dorsal pons was found. At microscopic examination, the right frontal tumor exhibited continuity with both the paraventricular and the right parietooccipital tumor. The right cerebral hemisphere and cerebellar vermis tumors showed protoplasmic astrocytoma; the dorsal pons tumor showed glioblastoma. CSF examination revealed no tumor cells. Tumor invasion of the internal capsule and the meninges was also not found. Accordingly, we diagnosed as multicentric astrocytoma of multiple histopathology. Only 11 case reports of multicentric glioma were recorded in Japan; only one of which was of multiple histopathology. Worldwide, only 7 case reports of multicentric glioma of multiple histopathology were recorded; this is the first case of protoplasmic astrocytoma and glioblastoma. Seen in terms of pathogenesis of multicentric glioma, this case is thought to be very interesting.

Astrocytoma↗
PubMed1987

[A case of aphasia with speech disorders by infarction of the left caudate nucleus and putamen].

An infarction involving the left putamen, caudate nucleus and the anterior limb of the internal capsule, resulted in aphasia with semantic paraphasias, verbal incoherence and verbal memory impairment. Cerebral blood flow (CBF) studies with 133Xe inhalation at 20 days post onset showed, on one hand, a bilateral lowering of cortical blood flow and on the other hand a left frontal-parietal hypoperfusion area. Spontaneous recovery occurred within 2 months. While the mean CBF became normal at 14 months post onset, a relative hypoperfusion area persisted on the anterior left hemispheric cortex. On the basis of these findings and current CBF and metabolic studies carried out in patients with subcortical lesions, the authors discuss the role of cortical and subcortical structures in subcortical aphasic syndromes. The importance of reciprocal connections between cortex, striatum and thalamus is stressed.

Aphasia↗
PubMed1986

[Hemodynamic and metabolic study using positron emission tomography in a case of right thalamo-capsular ischemic stroke].

The authors report the results of a Positron Emission Tomographic (PET) study of local cerebral blood flow and oxygen consumption in one patient with a right capsulo-thalamic ischemic lesion. That lesion is well demonstrated using X-ray CT Scan. PET study demonstrates a decreased perfusion and metabolism at three levels: first in right thalamus region, second in whole right hemisphere, more marked at orbitofrontal area and third at the level of the left cerebellar hemisphere. The authors point out the usefulness of PET studies which allow a better understanding of clinical signs by demonstrating functional consequences of damage in deeply located structures such as thalamus and internal capsule on cerebral and cerebellar cortices.

Brain↗
PubMed1986

[Hemiataxia and ipsilateral sensory deficit. Infarct in the area of the anterior choroidal artery. Crossed cerebellar diaschisis].

A 58 year old hypertensive man suffered an acute right-sided hemiataxia associated with painful hypoesthesia. CT showed an infarct in the territory of the left anterior choroidal artery. The sensory defect involved all the elementary modes, but predominated on pain sensation. The ataxia suggested a cerebellar type of dysfunction, with hypermetria, intentional tremor, dysdiadochokinesia and a positive rebound phenomenon. There was no hemiparesis, no hemianopia, no neuropsychological dysfunction and no oculomotor abnormality. Hemiataxia with hemisensory defect has not been reported in stroke, and it constitutes a new clinical form of lacunar syndrome. The hemiataxia may be related to the finding on single-photon emission computed tomography (SPECT) using 123 I-amphetamine of a crossed cerebellar diaschisis, which may suggest a transneuronal deactivation. This metabolic depression may have been due to involvement of the temporo-parieto-pontine bundle of Türck in the retro and sub-lenticular portion of the internal capsule. The finding of a normal cortical blood flow may explain why no neuropsychological impairment was present, because of the absence of functional deactivation of the cortex by the underlying deep infarct.

Arteries↗