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At least 505 records · Page 28Linked to original sources
PubMed2000

Supracapsular bed nucleus of the stria terminalis contains central and medial extended amygdala elements: evidence from anterograde and retrograde tracing experiments in the rat.

Neurons that accompany the stria terminalis as it loops over the internal capsule have been termed collectively the supracapsular bed nucleus of the stria terminalis (BSTS). They form two cell columns, a lateral column and a considerably smaller medial column. The lateral column merges rostrally with the lateral bed nucleus of the stria terminalis and caudally with the central amygdaloid nucleus (central extended amygdala components). The medial column is continuous with the medial bed nucleus of the stria terminalis and the medial amygdaloid nucleus (medial extended amygdala districts). The connections of the BSTS were investigated in the rat by placing injections of Phaseolus vulgaris-leucoagglutinin (PHA-L) or retrograde tracers in different parts of the extended amygdala or in structures related to the extended amygdala. BSTS inputs and outputs were identified, respectively, by the presence of varicose fibers and retrogradely labeled neurons within the stria terminalis. The results suggest that the medial-to-lateral compartmentalization of BSTS neurons reflects their close alliance with the medial and central divisions of the extended amygdala. The medial BSTS contains primarily elements that correspond to the posterodorsal part of the medial amygdaloid nucleus and the medial column of the posterior division of the medial bed nucleus of the stria terminalis, and the lateral BSTS contains elements that correspond to the medial and lateral parts of the central amygdaloid nucleus and lateral bed nucleus of the stria terminalis. These results add strong support to the concept of the extended amygdala as a ring-like macrostructure around the internal capsule, and they are of theoretical interest for the understanding of the organization of the basal forebrain.

Afferent Pathways↗
PubMed1997

Electrophysiologic target localization in posteroventral pallidotomy.

The current interest in stereotactic posteroventral pallidotomy (PVP) for treating Parkinson's disease and the variability of published results have raised questions regarding techniques for target localization. In our technique the probe is guided to the optimum target at the most ventral pallidum and ansa lenticularis by macroelectrode stimulation of the internal capsule and optic tract from within the globus pallidus, with the thresholds providing a relative measure of the electrode proximity to these structures. We have characterized these localizing macroelectrode stimulation parameters in 57 posteroventral pallidotomies with consistent anatomic lesion placement, excellent outcome, and no complications. Using a 1.8 x 2.0 mm radiofrequency electrode for macroelectrode stimulation (RFG-3C, Radionics Inc.), minimum voltages (thresholds) to activate motor (at a frequency of 2 Hz) or visual (at a frequency of 100 Hz) responses as well as impedance measurements were obtained at the final target (Tf) and at distances proximal to Tf along the electrode trajectory. The visual and motor threshold voltages at Tf via our standard approach angles (50 degrees above base plane, 20 degrees from the sagittal plane), had a range of 1.0 to 1.5 V, and 2.0 to 3.5 V respectively. We also found that as the probe approaches Tf there is a significant decrease in voltage thresholds for motor (P < .0001) and visual (P < .0001) responses in an individual patient indicating that the probe is converging on these structures. Increases in impedance between Tf, 2-3 mm, and 4-5 mm proximal to Tf were also statistically significant (P < .0001). Microelectrode recording to electrophysiological neuronal activity at various points along the trajectory towards the target showed distinct firing patterns providing identification of the globus pallidus externus and internus, ansa lenticularis, and optic tract. Macroelectrode electrophysiological stimulation within the target volume, inducing threshold responses in the internal capsule and optic tract, provides for accurate localization of the most effective PVP target in the ansa lenticularis. In unresponsive patients, the utilization of microelectrode recording for the identification of the pallidal borders and the optic tract improves safety.

Adult↗
PubMed1991

Morphology of corticothalamic terminals arising from the auditory cortex of the rat: a Phaseolus vulgaris-leucoagglutinin (PHA-L) tracing study.

Phaseolus vulgaris-leucoagglutinin (PHA-L) injection in the auditory cortex of the rat labeled anterogradely corticothalamic axons whose trajectory, morphology of terminals and their distribution were analyzed in light microscopy. From the primary auditory cortex, corticofugal axons ran in a rostral direction in the white matter (external capsule), and reached the internal capsule by crossing the caudate putamen. Then, they turned caudally, crossed the reticular nucleus (RE) of the thalamus, where some of them were seen to give off collaterals, ramifying in the 'auditory sector' of RE. From RE, the parent corticofugal axons continued in a caudal and medial direction to enter in the medial geniculate body (MGB). Corticofugal axons from the auditory cortex gave rise to 2 distinct types of terminals in the thalamus. First, small boutons (about 1 micron in diameter) were observed in the ventral division of the MGB (v-MGB; the main auditory relay nucleus in the thalamus), in RE, in the lateral part of the posterior thalamic nucleus, in the dorsal division of the MGB (d-MGB), as well as occasionally in the medial division of the MGB. Giant terminals (5-10 microns in diameter) formed the second type of cortical terminals, only present in a restricted zone of the ventral portion of d-MGB. Both types of terminals were observed as boutons 'terminaux' and 'en passant'. The zone of termination in v-MGB and RE varied as a function of the site of cortical injection. The similarity in the morphology and distribution of the terminals of corticothalamic axons arising from the primary auditory cortex with those of the primary somatosensory cortex of the mouse is striking and points to the existence of a basic pattern of connectivity used in corticothalamic processing of sensory information in rodents.

Animals↗
PubMed1988

The effects of mixing capsule geometry on the early compressive strength of dental amalgam.

Three dental amalgams were mixed in a number of different mixing capsules. Compressive strength specimens were prepared using a clinically relevant technique and tested at 1 h and 7 days. The results showed that the early compressive strength of an alloy was influenced by the mixing capsule, and suggested that internal capsule geometry may be an important contributory factor in capsule performance. With one exception, there was a marked difference between the compressive strengths produced under the present method and those reported by manufacturers under test conditions laid down in standards specifications.

Capsules↗
PubMed1999

Cerebral blood flow in pure dysarthria: role of frontal cortical hypoperfusion.

BACKGROUND AND PURPOSE: Isolated dysarthria, termed pure dysarthria, develops rarely after stroke, and its pathophysiology remains unclear. To clarify the underlying mechanism of pure dysarthria, we investigated lesion sites and cerebral blood flow in patients with pure dysarthria. METHODS: We examined 12 patients with pure dysarthria who underwent MRI and cerebral blood flow study. To visualize cortical blood flow, a three-dimensional display was generated from single-photon emission computed tomography (SPECT). Regional cerebral blood flow of the patients was semiquantitatively measured with SPECT and N-isopropyl-p[123I]iodoamphetamine as a tracer and compared with that of 11 control subjects. RESULTS: On MRI, multiple lacunar infarctions were noted bilaterally in 11 patients, all of whom had lesions involving the internal capsule or corona radiata. The other patient had a unilateral internal capsule-corona radiata infarction. Three-dimensional display showed frontal cortical hypoperfusion in 8 patients. Since interhemispheric differences of blood flow were not significant in any region of the 12 patients, the mean of left and right cortical blood flow was analyzed. Compared with the control subjects, cortical perfusion was significantly reduced in the patients' frontal regions, sparing the sensorimotor, temporal, and parietal cortices and the cerebellum. Reductions of perfusion were rather pronounced in the anterior opercular, medial prefrontal and premotor, and anterior cingulate regions. CONCLUSIONS: Pure dysarthria results mainly from multiple lacunar infarctions, which induce frontal cortical hypoperfusion, probably due to interruption of corticosubcortical networks. We conclude that frontal cortical hypoperfusion, particularly in the anterior opercular and medial frontal regions, plays an important role in the development of pure dysarthria.

Aged↗
PubMed2004

Contribution of diffusion tensor imaging to delineation of gliomas and glioblastomas.

PURPOSE: To determine if the diffusion tensor imaging (DTI) parameters fractional anisotropy (FA) and mean diffusivity (MD) can differentiate between accompanying edema and tumor cell infiltration of white matter (WM) beyond the tumor edge as defined from conventional MRI in low- and high-grade gliomas. MATERIALS AND METHODS: We examined 12 patients with high-grade gliomas/glioblastomas and eight patients with low-grade gliomas and compared them to 10 patients with meningiomas, in which no tumor infiltration is expected. The tumor was defined as the enhancing area in glioblastomas and meningiomas and as the area of increased T2-signal in low-grade gliomas. FA and MD were measured in the center of the tumor and in the adjacent WM. The contralateral WM and internal capsule were used as an internal standard. RESULTS: Comparing the WM areas of increased T2-signal adjacent to meningiomas and glioblastomas, we saw a trend (without significance) towards a reduction of FA, but not of MD, in glioblastomas. We found no changes of FA and MD in the WM adjacent to low-grade gliomas (without T2-signal increase) compared to the WM of the contralateral hemisphere. In meningiomas and high-grade gliomas/glioblastomas, a narrow rim of significantly (P < 0.01) increased FA and decreased MD values around the enhancing tumor area was seen, whereas in low-grade gliomas, such a rim could not be defined. There was no contribution of FA or MD to grading of gliomas. CONCLUSION: In glioblastomas, a reduction of FA in the edematous area surrounding the tumor may indicate tumor cell infiltration, but a reliable differentiation between infiltration and vasogenic edema is not yet possible on the basis of DTI. The additional finding of a narrow rim of increased FA and decreased MD at the edge of glioblastomas (as well as in meningiomas) may be caused by com-pressed WM fibers and/or increased vascularity, but does not contribute to exclude peripheral cellular infiltration.

Brain↗
PubMed1998

[Acute poisoning by carbon monoxide affecting the extrapyramidal system].

A case record of a 19-year old women acutely poisoned by carbon monoxide is presented. The state of the patient was very serious with loss of consciousness, cerebral oedema and acute circulatory failure, manifested by pulmonary oedema. The presence of carboxyhemoglobin in concentration of 45% was found in the blood. During the second week after the incident, extrapyramidal symptoms, manifested by hyperkinetic-hypokinetic syndrome with predominant involuntary movement, was observed. The diagnostic examinations of the central nervous system showed necrosis of globus pallidus, external capsule and a part of internal capsule.

Acute Disease↗
PubMed1983

Sonographic differentiation of extra- and intrahepatic masses.

The sonographic features in the evaluation and differentiation of extra- and intrahepatic masses were assessed in two groups of patients. These signs included discontinuity of the liver capsule, internal invagination or external bulging of the liver capsule, formation of a retroperitoneal fat wedge, displacement of the intrahepatic portal vessels or hepatic veins, shift of the inferior vena cava, and displacement of the right kidney. Evaluation of the results in 25 patients in whom the mass was intrahepatic and in 33 with an extrahepatic mass indicates that internal invagination of liver capsule (81.8%), its discontinuity (33.3%), formation of triangular fat wedge (75.7%), shift of the inferior vena cava anteromedially (36.3%), and anterior displacement of right kidney (28.1%) are the signs most frequently observed in extrahepatic masses. The characteristic features of the intrahepatic masses were displacement of hepatic vascular radicles (84%), external bulging of the liver capsule (56%), and posterior shift of the inferior vena cava (32%). The evaluation of masses in the right upper abdomen according to these criteria gives an accurate definition of their anatomic origin. However, masses exceeding 10 cm in diameter may present diagnostic problems.

Adenocarcinoma↗
PubMed2002

A 15-year-old boy with central nervous system vasculopathy presenting with dysarthria-clumsy hand syndrome.

Dysarthria-clumsy hand stroke syndrome has been described frequently in adults but not in children. We report a 15-year-old right-handed boy with sudden onset of dysarthria, dysphagia, right facial weakness, and mild right-hand clumsiness. Computed tomographic scan and magnetic resonance imaging demonstrated infarction in the genu and posterior limb of the left internal capsule. Magnetic resonance angiography and conventional angiography demonstrated stenosis of the supraclinoid portion of the left internal carotid artery and the origin of the left ophthalmic artery. Lacunar infarction in an older adult is not the only mechanism leading to dysarthria-clumsy hand syndrome.

Adolescent↗
PubMed1991

An immunohistological study of macrophages in the human fetal brain.

Brains from human fetuses of 13 to 27 weeks gestation have been examined immunohistologically for the presence of macrophages using the marker alpha-1-anti-chymotrypsin. A preliminary study demonstrated this to be a satisfactory marker of brain macrophages, although macrophages were also weakly positive for the more specific marker MAC-387. Macrophages were widely present within the cerebral hemispheres following their rapid accumulation between 14 and 16 weeks of gestation. They were identified in characteristic locations which, in the earliest gestation brains examined at 13 weeks, included the mid-line of the corpus callosum, around the optic tract and at the junction of the external and internal capsules near the apex of the putamen. Subsequently, macrophages were identified in abundance in the internal and external capsules and, by 22 weeks gestation, in the periventricular tissues. Their consistent presence and distribution indicate that at least the majority of these macrophages are a normal feature of the developing brain possibly related to remodelling processes.

Brain↗
PubMed2001

MR imaging of seven presumed cases of central pontine and extrapontine myelinolysis.

MRI was performed in seven patients with presumed central pontine and extrapontine myelinolysis. The underlying diseases were diabetes, lung cancer, Wilson disease, trauma, alcoholism, renal insufficiency and hemodialysis. CPM was found in four cases (in two of them extrapontine lesions were considered as resulting from Wilson disease), CPM and EPM in three patients. The localization of extrapontine changes included cerebellum, cerebral peduncles, caudate and lentiform nuclei, internal capsules, white matter and cortex of the cerebrum.

Adolescent↗
PubMed2001

Lacunar infarct during pallidotomy: case report.

A symptomatic lacunar infarct is an unusual complication which may develop during stereotactically guided pallidotomy using radiofrequency thermoablation. We describe a 54-year-old man with Parkinson's disease involving predominantly the right side, progressively deteriorating under medical management. He underwent stereotactically guided radiofrequency thermoablation of the posteroventral globus pallidus interna. Despite intraoperative microelectrode recording and stimulation, the patient developed right facial weakness and pronator drift during the procedure. MRI showed a small lacunar infarct in the left internal capsule, in addition to the appropriately placed ablative lesion. We discuss the potential mechanisms for this type of injury.

Brain Infarction↗
PubMed1996

Anterior commissure of the wallaby (Macropus eugenii): adult morphology and development.

In metatheria, all neo- and paleo-cortical commissural connections are made by the anterior commissure. We have examined the adult morphology of this commissure and its development in a diprotodontid metatherian, the wallaby (Macropus eugenii), at both the light and electron microscope level. The total number of axons in the adult anterior commissure was 21.7 million, of which 55-62% were myelinated. The dorsal two thirds of the commissure, containing neocortical commissural axons, showed a higher percentage of larger, myelinated axons than the ventral one third, which contains paleocortical commissural axons. The commissure also showed a topographical gradient, with cells in the dorsal cortex projecting through the dorsal region of the commissure, the fasciculus aberrans. In the rostrocaudal axis, axons from the frontal cortex tended to pass more anteriorly through the commissure and those from the occipital more posteriorly, but there was extensive overlap of projections from different areas. The gestation length of this wallaby is 28.3 days, and all commissural development occurs postnatally. The anterior commissure first appeared at P (postnatal day) 14, at which time commissural fibres were apparently derived from the external capsule exclusively. Commissural fibres passing through the internal capsule, and joining the anterior commissure via the fasciculus aberrans, were first noted at P18. By that age there were 94,000 to 161,000 axons. Peak axon counts of 50 to 63 million occurred between P100 and P150. The number of growth cones in a single midline section peaked at approximately P114 (480,000) and dropped to 0 by P170. The distribution of growth cones was analysed during the early stages of anterior commissure development (P18, P30, P82). At P18, growth cones were concentrated in the dorsal parts of the commissural bundle, suggesting a ventrodorsal sequence of addition of axons. There was no apparent preferential association of growth cones with the periphery of the commissure or glial structures at any of the three ages examined. The results show that axonal overproduction and regression in cortical commissural connections are features of development in diprotodontid metatheria, as in eutheria.

Age Factors↗
PubMed1986

[Evaluation of the hypertensive intracerebral hematoma based on the study on long-term outcome--Part I. Mode of hematoma extension and its clinical significance in putaminal hemorrhage].

A retrospective analysis of our series of 355 cases of putaminal hemorrhage revealed some interesting aspects of its pathogenesis. All the cases were studied in detail with special attention to clinical presentation, diagnostic findings and the long-term clinical outcome. Role of surgery in management of putaminal hemorrhage is still controversial. Inability to form proper useful classification has been one of the reasons responsible for this controversy. A new classification is formulated which divides putaminal hemorrhage into four types. Mild type has hematoma localized to external capsule while moderate type shows hematoma extension to corona radiata from external capsule. In severe type, hematoma extends to internal capsule also while in very severe type it further extends to midbrain. These four types could be very well correlated to long-term clinical outcome. Accessory hematoma is discussed in detail. It is found to be more common in severe and very severe types. Its presence in mild or moderate types results in worse clinical outcome. Hypertension (BP greater than 200 mm of Hg) may play an important role in further extension of hematoma.

Cerebral Hemorrhage↗
PubMed1980

[Difficulties and errors in diagnosing exudative pericarditis].

The peculiar features of the course of atypical variants of pericarditis with effusion are considered on the basis of concrete clinical cases, and the informative value of some symptoms and their reliability in making the diagnosis are discussed. Examples are given of patients with adhesive pericarditis with effusion some of whom developed heart tamponade with fluid in the formation of a non-stretchable external capsule and others had compression by the internal capsule.

Aged↗
PubMed2001

Contraversive eye deviation during deep brain stimulation of the globus pallidus internus.

Clinical signs help determine correct electrode positioning during stereotactic implantation for chronic high-frequency pallidal stimulation in Parkinson's diease (PD). The authors describe a patient who had marked, sustained, contraversive eye deviation caused by stimulation during pallidal surgery. The underlying mechanism is probably an excitation of fibers in the internal capsule by volume-conducted current spread. Such conjugate eye deviation is thus not necessarily an indication of incorrect electrode placement.

Electric Stimulation Therapy↗
PubMedDate not supplied

Diffusion-weighted MR imaging in neonatal nonketotic hyperglycinemia.

To our knowledge, we are the first to report the diffusion-weighted MR imaging findings in a 15-day-old neonate with nonketotic hyperglycinemia. We found bilaterally symmetrical lesions of restricted diffusion in the dorsal brain stem, cerebral peduncles, and posterior limbs of the internal capsule, which were more conspicuous and extensive on diffusion-weighted MR images than on T2-weighted images. These lesions are in the myelinated tracts of the neonate and are compatible with the expected sites of abnormality in vacuolating myelinopathy.

Brain↗