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PubMed1977

Nigro-amygdaloid fiber connections in the cat.

Relatively discrete unilateral lesions were made in the lateral portion of the substantia nigra of eight cats and in the medial substantia nigra of two. After a 10-day survival period the animals were killed, brains were stored in buffered 10% formalin, and frozen sections were stained for degenerating axons and terminals, or by Weil and cresyl violet methods. Electordes passed through the midial suprasylvian gyrus, pulvinar and/or posterolateral thalamic nucleus and the medial geniculate body. The stria terminalis and hippocampus were undamaged. Degeneration from the lesion followed two paths. One projected through the reticular nucleus into the internal capsule and then ventrolaterally below the putamen to enter the lateral and central amygdaloid nuclei, with degenerated terminals. The second path ran dorsolaterally in the internal capsule to enter the external capsule where some of the fibers spread into the lateral amygdaloid nucleus. It appears that some of the terminals in the lateral amygdaloid nucleus are from the external capsule. Perhaps these connections link the extrapyramidal system to the amygdaloid body.

Amygdala↗
PubMed1989

[Homolateral ataxic hemiparesis].

20 cases with homolateral ataxic hemiparesis caused by stroke were reported in this article. The main clinical manifestations were: 1. Only mild motor weakness could be found, lower limb was more severe than upper arm for most of the patients; 2. There was a definite cerebellar ataxia which was out of proportion to the mild degree of weakness; 3. The incidence of facial palsy was more frequent than tongue palsy; 4. Most of these patients had heminumbness of the limb. According to the finding of CT, the localization was in the outside of the body of lateral ventricle for 8 cases; in the posterior limb of internal capsule and superior portion of it for 3 cases; in the ventral portion of pons for 1 case and superior portion of anterior limb of internal capsule for 1 case. The main cause of this disease was hypertensive arteriosclerosis, and the prognosis of these patients was benign.

Aged↗
PubMed2006

Axial and radial diffusivity in preterm infants who have diffuse white matter changes on magnetic resonance imaging at term-equivalent age.

OBJECTIVE: Diffuse excessive high signal intensity (DEHSI) is observed in the majority of preterm infants at term-equivalent age on conventional MRI, and diffusion-weighted imaging has shown that apparent diffusion coefficient values are elevated in the white matter (WM) in DEHSI. Our aim was to obtain diffusion tensor imaging on preterm infants at term-equivalent age and term control infants to test the hypothesis that radial diffusivity was significantly different in the WM in preterm infants with DEHSI compared with both preterm infants with normal-appearing WM on conventional MRI and term control infants. METHODS: Diffusion tensor imaging was obtained on 38 preterm infants at term-equivalent age and 8 term control infants. Values for axial (lambda1) and radial [(lambda2 + lambda3)/2] diffusivity were calculated in regions of interest positioned in the central WM at the level of the centrum semiovale, frontal WM, posterior periventricular WM, occipital WM, anterior and posterior portions of the posterior limb of the internal capsule, and the genu and splenium of the corpus callosum. RESULTS: Radial diffusivity was elevated significantly in the posterior portion of the posterior limb of the internal capsule and the splenium of the corpus callosum, and both axial and radial diffusivity were elevated significantly in the WM at the level of the centrum semiovale, the frontal WM, the periventricular WM, and the occipital WM in preterm infants with DEHSI compared with preterm infants with normal-appearing WM and term control infants. There was no significant difference between term control infants and preterm infants with normal-appearing WM in any region studied. CONCLUSIONS: These findings suggest that DEHSI represents an oligodendrocyte and/or axonal abnormality that is widespread throughout the cerebral WM.

Brain↗
PubMed1999

Variability in lesion location after microelectrode-guided pallidotomy for Parkinson's disease: anatomical, physiological, and technical factors that determine lesion distribution.

OBJECT: To understand the factors that determine the distribution of lesions after microelectrode-guided pallidotomy for Parkinson's disease, the authors quantitatively characterized lesion location in a cohort of patients who were prospectively followed to determine the effects of pallidotomy on clinical outcome. METHODS: Thirty-three patients underwent volumetric magnetic resonance (MR) imaging after surgery to allow quantitative lesion localization in relation to conventional intraventricular landmarks and, alternatively, more anatomically relevant landmarks. The validity of the method was verified in a cohort of postpallidotomy patients who underwent concurrent volumetric and stereotactic MR imaging in an external head frame. Lesions were distributed over a considerable distance in the anteroposterior (8.8 mm) and mediolateral (8.7 mm) dimensions in relation to the anterior commissure and wall of the third ventricle, respectively. Less variation was seen in lesion location in the dorsoventral dimension (4.8 mm) in relation to the intercommissural plane. CONCLUSIONS: Lesion distribution was not random: lesion locations in the anteroposterior and mediolateral dimensions were highly correlated, such that lesions were distributed from anteromedial to posterolateral, parallel to the border of the globus pallidus internus with the obliquely oriented internal capsule. The factors that led to variability in lesion location were variation in third ventricle width and the oblique anteromedial-to-posterolateral course of the internal capsule. This demonstration of variability of lesion location in a cohort of patients who experienced excellent clinical benefits and minimal postoperative complications emphasizes the importance of anatomical variations in determining lesion position and the need for physiological corroboration for correct lesion placement.

Adult↗
PubMed1993

Syrinx extending from conus medullaris to basal ganglia: a clinical, radiological, and pathological correlation.

A 41-year-old woman with a history of birth injury to the brachial plexus suffered several delayed episodes of neurological deterioration. Magnetic resonance imaging studies revealed a syrinx extending from the conus medullaris into the brainstem and rostrally into both internal capsules. She died of an acute exacerbation of chronic respiratory failure. Autopsy demonstrated syringomyelia and syringobulbia with cavity extension bilaterally along the corticospinal tracts into the internal capsules. Islands of glial tissue in the subarachnoid space around the medulla caused obstruction of the subarachnoid space at the foramen magnum. These were probably the result of birth injury to the cerebellum. A detailed clinico-pathological correlation is provided to explain her neurological deficits. The pathogenesis of syrinx formation is discussed in terms of a late manifestation of birth trauma.

Adult↗
PubMed1996

[Neuroradiological findings of sporadic olivopontocerebellar atrophy with marked laterality and degenerative changes in the corticopontine tract].

We report a case of sporadic olivopontocerebellar atrophy (OPCA) with marked laterality of cerebellar atrophy and degenerative changes in the corticopontine tract. A 35-year-old man was admitted to our hospital for evaluation of titubation, gait disturbance, dysarthria, and urinary and fecal incontinence. Neurological examination showed a wide based gait, slurred speech, truncal ataxia, slightly saccadic ocular movement, and finger-to-nose incoordination, greater on the right than the left. Deep tendon reflexes were hyperactive and preserved with the right side greater than the left. Bilateral Babinski signs were present, and the patient had neurogenic bladder without orthostatic hypotension. Cranial MRI showed atrophy of the cerebellum with right dominance and of the pons. On T2- and PD-weighted images, high-intensity areas were detected at the left internal capsule, crus cerebri and ventral pons. These findings were compatible with the right dominance of the clinical symptoms. The high intensity area detected at the posterior internal capsule was more extensive than that seen in patients with motor neuron disease. This finding may coincide with the degenerative changes in the corticopontine tract. Moreover, 99mTc-HMPAO-SPECT showed the crossed cerebello-cerebral diaschisis (CCCD) pattern, which indicates the decreased CBF in the right cerebellar hemisphere and the left frontal lobe. These findings may reflect degenerative changes in the corticopontine tract in OPCA.

Adult↗
PubMed1976

Taste pathways to hypothalamus and amygdala.

The projections of a third order gustatory relay in the dorsal pons of rats have been traced using tritiated proline autoradiography and antidromic activation of pontine neurons from electrodes in the thalamus and amygdala. Labelled axons collect in the central tegmental tract and ascend to the thalamic taste area in the medial extension of the ventrobasal complex. The majority of the fibers remain ipsilateral, but a few cross in the rostral pons and midbrain. The largest crossing occurs at the level of the thalamic termination. Many fascicles of fibers continue rostrally by passing beneath the thalamic taste area, piercing the medial lemniscus, and spreading out along the dorsomedial corner of the internal capsule (IC). The terminal field at this level caps IC from the subthalamic nucleus down into the far-lateral hypothalamus. Labelled axons grandually penetrate through the internal capsule, and ramify throughout the underlying substantia innominata. This terminal zone extends laterally into the rostral end of the central nucleus of the amygdala, which is densely labelled to its caudal exremity. At the caudal end of the amygdala labelled fibers are visible in one component of the stria terminalis. These fibers can be followed over the dorsal thalamus into a smaller, but equally dense terminal area in the dorsolateral bed nucleus of the stria terminalis. The electrophysiological data demonstrate that pontine gustatory units can be antidromically activated by electrodes located in or near the central nucleus of the amygdala. Since many of the same units can also be driven from the thalamic taste area, at least some of the axons traced autoradiographically probably convey gustatory information to the hypothalamus and amygdala.

Amygdala↗
PubMed1986

Spinal neuronal inhibition and EEG synchrony by electrical stimulation in subcortical forebrain regions of the cat.

In cats anaesthetized with sodium pentobarbital and 70% N2O, single lumbar dorsal horn neurons were excited by controlled noxious radiant heating of glabrous hindpaw skin. The EEG was recorded from the pericruciate cortex and posterior lateral gyrus. Subcortical forebrain sites where electrical stimulation inhibited dorsal horn neuronal heat-evoked responses contralaterally were identified by mapping the caudate nucleus, internal capsule, septum, nucleus accumbens and basal forebrain regions. Inhibitory sites were mainly located in the ventral forebrain (ventral septum, diagonal band, basal forebrain). The caudate nucleus and internal capsule had a low incidence and effectiveness of inhibitory sites. In the basal forebrain, the incidence and effectiveness of inhibitory sites decreased from caudal to rostral regions. There was a rostral limit of inhibitory sites, both medially and laterally. The magnitude of inhibition increased with graded increases in brain stimulation intensity. The mean incremental increase in inhibition was greater for caudal than for rostral basal forebrain sites. Mean stimulus currents for threshold of inhibition and for inhibition to 50% of control heat responses were lower for caudal than for rostral sites. Responses of the dorsal horn neurons to increasing temperatures of noxious skin heating were monotonic linear functions over the temperature range studied (48-53 degrees C). Stimulation in both rostral and caudal basal forebrain decreased the slope of this stimulus-response function, with a greater decrease for caudal sites. Cortical EEG synchronization was evoked by stimulation in the caudate nucleus and rostral basal forebrain. For both regions, most synchronogenic sites did not produce descending inhibition of dorsal horn neurons. The significance of these findings in relation to descending inhibition from other brain regions and stimulation-produced analgesia is discussed.

Action Potentials↗
PubMed1986

An autoradiographic study of the postnatal development of pericruciate cortical projections to the neostriatum and the claustrum of the cat.

The postnatal development of corticostriatal and corticoclaustral projections was traced by light-microscopic autoradiography following injections of tritiated proline and leucine into the pericruciate cortex of kittens, 2-56 days of age, and adult cats. A medial-lateral topography of the corticostriatal pathways was present at birth, with a smaller and more restricted projection arising from the lateral pericruciate region. During postnatal development, the volume of the ipsilateral caudate nucleus filled by labelled corticostriatal fibers was reduced by 30% and these projections became constricted within the dorsolateral head and body of the caudate nucleus. During the first postnatal week, terminal fields were diffuse but lacked homogeneity since irregular patches of intensely labelled elements clustered near the internal capsule. By the end of the first month, a fenestrated organization became apparent within the caudate nucleus where elongated clusters of intensely labelled fibers radiated from the internal capsule and partially or completely surrounded islands of neuropil virtually devoid of label. Pericruciate inputs were confined to the dorsal parts of the rostral putamen and claustrum and the patchy nature of these terminal fields was limited to small labelled clusters close to the capsular margins. Contralateral terminal fields were labelled less intensely and occupied areas symmetrical to those within the ipsilateral neostriatum and claustrum.

Amino Acids↗
PubMed2003

Neurophysiological criteria for intraoperative prediction of pure motor hemiplegia during aneurysm surgery. Case report.

The value of motor evoked potentials (MEPs) as an intraoperative neurophysiological monitoring tool for detecting selective subcortical ischemia of the motor pathways during intracerebral aneurysm repair is described and the use of such measures to predict postoperative motor status is discussed. The authors present the case of a 64-year-old woman in whom there was an incidental finding of two right middle cerebral artery (MCA) aneurysms. During the aneurysm clipping procedure, an intraoperative MEP loss in the left abductor pollicis brevis and tibial anterior muscles occurred during an attempt at permanent clip placement. There were no concurrent changes in somatosensory evoked potentials. Postoperatively, the patient demonstrated a left hemiplegia with intact sensation. A computerized tomography scan revealed an infarct in the anterior division of the MCA territory, including the posterior limb of the internal capsule. In this patient, intraoperative neurophysiological monitoring with MEPs has been shown to be a sensitive tool for indicating subcortical ischemia affecting selective motor pathways in the internal capsule. Therefore, intraoperative loss of MEPs can be used to predict postoperative motor deficits.

Aneurysm↗
PubMed1992

[Studies on motor neuron disease with cranial magnetic resonance imaging].

The present study was performed to examine the pyramidal tracts of the brain in both 51 normal subjects (21 male and 30 female subjects; mean age of 43.5 +/- 16.1 years) and 12 patients with motor neuron disease (6 male and 6 female patients; mean age of 57.4 +/- 7.9 years), using the magnetic resonance imaging (MRI). The 12 patients with motor neuron disease (MND) comprised 7 suffering from spinal progressive muscular atrophy (SPMA) and 5 from amyotrophic lateral sclerosis (ALS). The MRI used in this study was of both short spin echo and long spin echo sequence. Of the 52 normal subjects, 24 of them (47%) had the T2 prolonged small areas (high signal intensity areas) at the posterior limb of internal capsule. These findings were not found in the normal subjects over fifty years old. No similar finding was detected in the pyramidal tracts except the posterior limb of internal capsule. On the other hand, 8 patients with MND (67%) proved to have the high signal intensity areas in the pyramidal tracts. Moreover, these high intensity areas were extended from the crus cerebri to corona radiata in 7 patients (58%). In all patients with ALS, these areas were extended in whole areas of the pyramidal tracts, and the similar findings were also found in two patients with SPMA. These findings were demonstrated to be more extensive than those in the normal subjects. The results thus obtained warrant us to conclude that cranial MRI is useful to detect the degeneration of the pyramidal tracts of MND patients.

Adolescent↗
PubMedDate not supplied

[Lacunar strokes: clinical conditions vs. localization of lesions in neuroimaging studies].

Clinical records of 89 patients with lacunar stroke were reviewed, to evaluate the occurrence of neurological syndrome and to correlate the frequency of its signs with the localization of ischaemic lesions seen in neuroimaging examinations. "Pure" motor paresis (50%) and sensory-motor paresis (27%) were the most common clinical syndromes. The localization in putamen and corona radiata (37%), or in anterior part of the internal capsule and in the head of the caudate nucleus (35%) were the most frequent sites of localization. In the group of patients with lesions in anterior part of internal capsule or with lesions in putamen and corona radiata "pure" motor paresis was the most common clinical syndrome. Additionally, in the group of patients with lesions in putamen and corona radiata sensory motor paresis was also frequently observed (44%). During one year of follow-up 22 patients died. Dysarthria and disability (Barthel Index < 60) were the independent predictors of one year mortality. Non-neurological complications were the main cause of death.

Aged↗
PubMed1976

Pallidothalamic projections in the rat.

The purpose of this investigation was to examine pallidofugal projections to the thalamus of the rat using a selective silver degeneration method and autoradiography. Degenerating pallidothalamic projections emerging from the anterior part of the pallidum formed two diffuse groups of fibers; one coursed ventromedially directly through the internal capsule without forming a lenticular fasciculus and terminated uniformly in the reticular, VA, VD, VM and the medial part of the VE. The otehr group coursed ventrolaterally in the internal capsule and, without forming an ansa lenticularis, entered the zona incerta, swept medially through and ventral to the medial lemniscus, and terminated in the medial part of the VE and throughout the VD.

Animals↗
PubMed1994

The anterior choroidal artery syndrome. I. Microangiography of the anterior choroidal artery.

The distribution of the anterior choroidal artery (AChA) was analysed on coronal, sagittal and axial microangiograms of cadaver brains. On axial sections, the territory of the AChA was confined to an arcuate zone between the striatum anterolaterally and the thalamus posteromedially. On sagittal sections, fine vessels from the cisternal part of the AChA were seen to extend upwards and somewhat posteriorly into the region of the posterior limb of the internal capsule. On coronal sections, ascending branches of the AChA coursed laterally and then upwards to penetrate the globus pallidus and the inferior portion of the posterior limb of the internal capsule, apparently terminating at the lateral border of the thalamus. Determining the distribution of this artery on multiplanar sections was helpful for interpreting pathological changes, including infarcts, occurring in this region on multiplanar CT and/or MR images.

Cerebral Angiography↗
PubMed1983

Intracranial stimulation for the control of chronic pain.

Long-term stimulation of deep brain structures for pain relief has been efficacious in a significant number of patients who have been total failures at every other means of pain control. Two primary sites are used at this time--the periventricular grey area, which is related to the endogenous opiate system, and the internal capsule system, which is related to the dorsal column projection system. Periventricular sites are more efficacious for externally generated pain, that is, pain with input through the dorsal horn. Internal capsule stimulation is more efficacious for central nervous system-generated pain. While the preoperative preparation and intraoperative testing as well as postoperative testing of these patients requires a great deal of time and tedious attention to detail, our long-term results have been excellent using a combined comprehensive pain unit approach to pain and stress management, plus the stimulation techniques in carefully selected patients. Our results would indicate that initially 80-85% of patients get good pain relief, and then that range decreases to between 50 and 60% over a long period of time. Deep brain stimulation for pain relief is not a technique that should be used on a large number of patients with simple pain problems, but is highly efficacious in a selected group of patients with very specific pain problems that do not respond to usual pain treatment techniques. In patients with pain generated by benign etiologies, it is far superior to destructive procedures and does not have the secondary side effects of sensory loss, postchordotomy dysesthesias, or secondary neurological deficits.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed2004

The addition of computer simulated noise to investigate radiation dose and image quality in images with spatial correlation of statistical noise: an example application to X-ray CT of the brain.

This study validates a method to add spatially correlated statistical noise to an image, applied to transaxial X-ray CT images of the head to simulate exposure reduction by up to 50%. 23 patients undergoing routine head CT had three additional slices acquired for validation purposes, two at the same clinical 420 mAs exposure and one at 300 mAs. Images at the level of the cerebrospinal fluid filled ventricles gave readings of noise from a single image, with subtraction of image pairs to obtain noise readings from non-uniform tissue regions. The spatial correlation of the noise was determined and added to the acquired 420 mAs image to simulate images at 340 mAs, 300 mAs, 260 mAs and 210 mAs. Two radiologists assessed the images, finding little difference between the 300 mAs simulated and acquired images. The presence of periventricular low density lesions (PVLD) was used as an example of the effect of simulated dose reduction on diagnostic accuracy, and visualization of the internal capsule was used as a measure of image quality. Diagnostic accuracy for the diagnosis of PVLD did not fall significantly even down to 210 mAs, though visualization of the internal capsule was poorer at lower exposure. Further work is needed to investigate means of measuring statistical noise without the need for uniform tissue areas, or image pairs. This technique has been shown to allow sufficiently accurate simulation of dose reduction and image quality degradation, even when the statistical noise is spatially correlated.

Aged↗
PubMed2005

White matter density in patients with schizophrenia, bipolar disorder and their unaffected relatives.

BACKGROUND: This study sought to assess white matter density in patients and relatives with histories of bipolar disorder and/or schizophrenia. METHODS: Subjects included those with schizophrenia from families affected by schizophrenia alone, those with bipolar disorder from families affected by bipolar disorder alone and those with bipolar disorder from families affected by both bipolar disorder and schizophrenia. Unaffected relatives of the three patient groups were also recruited. Subjects underwent an MRI brain scan which was analyzed using a white-matter optimized technique. RESULTS: Subjects with schizophrenia and bipolar disorder showed reduced white matter density in the anterior limb of the internal capsule which was not found in unaffected relatives. Reductions were found in frontal subgyral white matter density in affected subjects with a family history of schizophrenia only. CONCLUSIONS: Abnormal anterior internal capsule white matter may provide a structural substrate for both disorders.

Adult↗
PubMed2000

[Normal myelination in childhood brains using MRI--a meta analysis].

PURPOSE: To establish age limits for the assessment of normal myelination of the brain on T1-weighted (T1w) and T2-weighted (T2w) images. METHOD: Comparison of previous publications (Barkovich et al. 1988, Grodd 1993, Hayakawa et al. 1990, Hittmair et al. 1994, Martin et al. 1988/1990/1991, Nakagawa et al. 1998, Staudt et al. 1993/1994, Stricker et al. 1990). RESULTS: Despite technical and methodological differences, these studies principally agreed on the timing of myelination for most regions of the brain. Thus, a common time-table could be established: At 1 month, myelin is visible on both T1w and T2w in the medulla oblongata, tegmentum pontis, cerebellar peduncles and vermis, quadrigeminal plate, decussation of superior cerebellar peduncles, thalamus, posterior limb of internal capsule, optic radiation, corona radiata. Thereafter, the myelin-typical signal in the different regions of the brain should be present at the following ages (M = months): anterior limb of internal capsule (2 M: T1w; 7 M: T2w), splenium of corpus callosum (4 M: T1w; 6 M: T2w), genu of corpus callosum (6 M: T1w; 8 M: T2w), centrum semiovale (2 M: T1w; 7 M: T2w). Branching of myelin into the gyri of the telencephalon (= arborization) appears at the latest at: occipital lobe (5 M: T1w; 12 M: T2w) and frontal lobe (7 M: T1w; 14 M: T2w). CONCLUSION: These extracted age limits can be used for a more reliable assessment of myelination than the time-tables from a single study.

Age Factors↗