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At least 37 records · Page 2Linked to original sources
PubMed1999

Axonal injury in the internal capsule correlates with motor impairment after stroke.

Background and Purpose--Magnetic resonance spectroscopy (MRS) in ischemic stroke has shown a correlation between N-acetylaspartate (NAA) loss from the infarcted region and disability. We tested the hypothesis that NAA loss in the descending motor pathways, measured at the level of the posterior limb of the internal capsule, would determine motor deficit after a cortical, subcortical, or striatocapsular stroke. Methods--Eighteen patients with first ischemic stroke causing a motor deficit were examined between 1 month and 5 years after stroke. T2-weighted imaging of the brain and localized proton (voxel, 1.5x2x2 cm3) MRS from the posterior limb of each internal capsule were performed and correlated to a motor deficit score. Results--Mean internal capsule NAA was significantly lower in the patient group as a whole compared with the control group (P<0.001). Reductions in internal capsule NAA on the side of the lesion were seen in cases of cortical stroke in which there was no extension of the stroke into the voxel as well as in cases of striatocapsular stroke involving the voxel region. There was a strong relationship between reduction in capsule NAA and contralateral motor deficit (log curve, r2=0.9, P<0.001). Conclusions--Axonal injury in the descending motor pathways at the level of the internal capsule correlated with motor deficit in patients after stroke. This was the case for strokes directly involving the internal capsule and for strokes in the motor cortex and subcortex in which there was presumed anterograde axonal injury.

Activities of Daily Living↗
PubMed1997

[Motor paresis with cheiro-oral topography due to small infarct in the internal capsule or the corona radiata].

We reported five patients having presented only with clumsy hand and dysarthria which resulted from motor paresis confined to one side of the fingers and the ipsilateral face and tongue. All of them were right-handed, and their manifestation was transient. They had no abnormalities of muscle tonus and sensation, and no ataxia. The features of these cases differed from those of the dysarthria-clumsy hand syndrome because of absence of ataxia, and could be distinguished from pure motor hemiplegia by a motor paresis with cheiro-oral topography. MRI examinations showed a localized lesion at the border between internal capsule and corona radiata (two cases), or in the corona radiata just over this region (three cases). In the former cases in which the internal capsule was involved, we confirmed the lesion in the genu and anterior half of the posterior limb of the internal capsule. The lesion was on the left side in all five patients. It has been known that the pyramidal tract consists of the large and small fibers. The large ones are localized in the posterior part of the posterior limb of the internal capsule, and the damage of them produces sustained and serious motor paralysis. The small ones are widely distributed in the genu and the posterior limb of the internal capsule. The findings of our study suggest that the small fibers have adjacent somatotopy for the hand and mouth in the region of the genu and the anterior part of the posterior limb of the internal capsule, and that the damage of them may lead to mild, transient motor paresis without spasticity.

Adult↗
PubMed2006

Internal capsule size in good-outcome and poor-outcome schizophrenia.

Converging lines of research suggest that white matter abnormalities may be central to the pathophysiology of schizophrenia. The purpose of this study was to examine regional white matter in the anterior limb of the internal capsules in patients with schizophrenia. The authors obtained high-resolution magnetic resonance imaging in 106 patients with schizophrenia and 42 age and sex-matched healthy comparison subjects. The area of the anterior limb of the internal capsule was measured at five proportionately spaced dorsal-to-ventral levels. Schizophrenia patients were divided into good-outcome and poor-outcome groups, based on longitudinal analysis of self-care deficits. Patients with poor-outcome had significantly smaller dorsal areas than healthy comparison subjects, but good-outcome patients did not differ from healthy comparison subjects. Larger relative volumes of the caudate, putamen, and thalamus tended to be associated with relatively larger volumes of the internal capsule in healthy comparison subjects and good-outcome patients, consistent with the known frontal-striatal-thalamic pathways. Larger ventricles were associated with smaller internal capsules, particularly in healthy comparison subjects. The findings suggest disruption of internal capsule fibers in poor-outcome patients with schizophrenia. These abnormalities may be independent of other structural changes in schizophrenia.

Adult↗
PubMed2001

Diffusion anisotropy of the internal capsule and the corona radiata in association with stroke and tumors as measured by diffusion-weighted MR imaging.

BACKGROUND AND PURPOSE: Diffusion-weighted MR images have enabled measurement of directionality of diffusion (anisotropy) in white matter. To investigate differences in the anisotropy for various types of pathologic findings and the association between the anisotropy of tracts and neurologic dysfunction, we compared the anisotropy of the posterior limb of the internal capsule and the corona radiata between patients with stroke and those with tumors and between patients with and without hemiparesis. METHODS: Thirty-three patients consisting of 11 with tumors and 22 with ischemic disease (16 acute infarction, four old infarction, and two transient ischemic attack) and nine control patients were studied with a 1.5-T MR imager. Diffusion-weighted images were obtained with diffusion gradients applied in three orthogonal directions. The diffusion anisotropy measurements were obtained from regions of interests defined within the internal capsule and the corona radiata. RESULTS: The diffusion anisotropy was significantly reduced in all internal capsules and coronae radiata involved by infarcts, tumors, and peritumoral edema compared with that of the control patients (P <.0001). This reduction was most prominent in the tracts involved by tumors (P <.05). The anisotropy of the internal capsules and coronae radiata was significantly decreased in cases with moderate-to-severe hemiparesis as compared with those with no or mild hemiparesis (P <.0001). Diffusion anisotropy tended to be also reduced in normal-appearing internal capsules and coronae radiata that were remote from the involved segment of the corticospinal tract. CONCLUSION: The degree of impaired diffusion anisotropy may vary in different pathologic conditions and correlate with neurologic dysfunction. The measurement of diffusion anisotropy may provide additional information relating to neurologic function and transneuronal effects.

Adolescent↗
PubMed1999

Asymmetrical myelination of the posterior limb of the internal capsule in infants with periventricular haemorrhagic infarction: an early predictor of hemiplegia.

AIM: To prospectively assess the predictive value of asymmetrical myelination on MRI of the posterior limb of the internal capsule (PLIC) in newborn infants with an intraventricular haemorrhage (IVH) associated with unilateral haemorrhagic parenchymal involvement (PI), for subsequent development of a hemiplegia. METHODS: 12 preterm infants (GA 25-36 wks) and 4 full-term infants were studied. Using cranial ultrasound (US), the pre-term infants were diagnosed to have an IVH with unilateral PI. The term infants presented with a porencephalic cyst (PC) on the first postnatal US, following an antenatal IVH with PI. MRI was performed at 40 wks postmenstrual age in the pre-term infants and during the first 2 weeks of life in the full-term infants, using a 1.5T magnet. Using an inversion recovery sequence, the myelination of the internal capsule was recorded as normal, abnormal or equivocal. Neurological assessment > or = 12 months disclosed the presence of a hemiplegia or asymmetry in tone pattern. RESULTS: All 4 cases with a normal internal capsule had a normal outcome in spite of the development of a PC. All 9 cases with an abnormal PLIC developed a hemiplegia, while 1 of the 3 cases with an equivocal PLIC is normal on neurological assessment, one developed a mild asymmetry in tone and 1 a mild hemiplegia. CONCLUSION: While a symmetrical signal intensity within the internal capsule on MRI, performed at 40 weeks PMA, in infants with an IVH and unilateral PI appears to be strongly related to a normal outcome, an asymmetrical PLIC is an early predictor of future hemiplegia.

Cerebral Infarction↗
PubMed1983

[Electrical stimulation of the posterior limb of the internal capsule for treatment of thalamic pain].

Electrical stimulation of the posterior limb of the internal capsule was performed in six patients with central pain due to vascular lesions of the thalamus. Three patients suffered from thalamic hemorrhage and the other three from ischemic insult. These patients developed dysesthesia, hyperpathia and spontaneous burning pain several months after cerebral vascular diseases. These severe pain were not relieved by any trials of anticonvulsants, psychopharmacological and analgesic drugs. Stimulating electrode system manufactured by Medtronic, Co. was implanted stereo-taxically in the posterior limb of the internal capsule which was 25 mm lateral to the posterior commissure. Ramped bipolar stimulation with a square pulse 2-3 V, 0.2 msec, 50 Hz elicited sensory response such as warm or comfortable sensation. Satisfactory relief of pain was obtained in most cases by 30-minutes-long stimulation twice or three times a day for various period of time ranging from 10 to 14 days. Long-term follow-up ranging from three months to two years showed that three patients had a good result (incomplete pain relief by stimulator with no medication required), two had a fair (incomplete pain relief by stimulator with decreased doses of medication) and another one had a poor result in which the pain had not been relieved with the stimulation in one month. No remarkable side effects were seen. These results indicate that the internal capsule stimulation is more effective and lasts longer than the various ablative methods to relieve central pain.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Hemorrhage↗
PubMed2000

Axonal injury or loss in the internal capsule and motor impairment in multiple sclerosis.

OBJECTIVE: To test the hypothesis that axonal damage extending into primarily normal-appearing white matter is clinically important by comparing the concentrations of N-acetylaspartate (NAA) bilaterally within the internal capsule with lateralization of motor impairment in patients with multiple sclerosis (MS) and persistent asymmetrical motor deficit. DESIGN: We performed magnetic resonance spectroscopy and T2-weighted imaging of the internal capsule, calculated central motor conduction times, and related these results to measures of motor function asymmetry in 12 patients with MS. RESULTS: Levels of NAA from normal-appearing white matter of the internal capsule in patients with MS were significantly lower than those in control subjects (P = .05). Side-to-side differences in NAA levels were also significantly greater in patients with MS than in controls (P = .01). There was a correlation between asymmetry in motor function for the left and right limbs and asymmetry of internal capsule NAA concentrations (r = 0.60; P = .04). This correlation seemed slightly stronger when tests specifically of arm and hand motor asymmetry were considered alone. Central motor conduction times were abnormal in most patients with MS and showed a side-to-side difference that also correlated with asymmetry in motor function. CONCLUSION: Our demonstration of a graded association between NAA concentrations within primarily normal-appearing white matter of a specific tract and functional impairments referable to that tract suggests that axonal pathology distant from macroscopic lesions might be an important determinant of disability in MS.

Adult↗
PubMedDate not supplied

Internal capsule: normal anatomy and ischemic changes demonstrated by computed tomography.

The purpose of this study was two-fold: (1) to attempt to localize the different parts of the internal capsule on computed tomography (CT) axial sections and (2) to correlate clinical data and CT appearance of 25 cases of ischemic capsular lesions. Twenty-three of the ischemic lesions produced a pure motor hemiplegia. The internal capsule was studied on routine CT axial sections parallel to the canthomeatal line with 8 mm collimation before and after intravenous contrast medium injection. Absorption values of the white matter at the level of the anterior limb of the internal capsule were found to be a little higher (mean, 32 Hounsfield units [H]) when compared with the posterior limb (mean, 28 H). Lesions were classified according to the topography of the internal capsule: anterior limb (three), genu (one), posterior limb (seven), and putaminocapsulocaudate (14). CT appears to be the most sensitive and reliable method to investigate small deep cerebral infarcts since isotope scans were positive in only two of 13 cases, while angiography was positive in eight of 17 cases.

Adolescent↗
PubMed1989

Focal signal-intensity variations in the posterior internal capsule: normal MR findings and distinction from pathologic findings.

Cranial magnetic resonance (MR) imaging studies in 117 control patients were reviewed to evaluate for focal signal-intensity variations in the posterior internal capsule. Rounded foci of increased signal intensity were found near the junction of the posterior limb and retrolenticular portion of the internal capsule on axial T2-weighted images in 56% of patients imaged at 1.5 T and in 50% imaged at 0.5 T. Corresponding hypointense foci were found on T1-weighted images in 64% of control patients imaged at 1.5 T and in 69% imaged at 0.5 T. With all sequences, the foci were homogeneous and well defined, without mass effect, and bilaterally symmetric. Comparison was made with MR imaging studies in 32 patients with pathologic involvement of the posterior internal capsule region. Symmetric morphology and signal intensity, sharply defined margins, confinement to a characteristic location, signal intensity approximating that of cortical gray matter on T2-weighted images, and isointensity or hypointensity on spin-density-weighted images appear to characterize normal posterior capsular foci and distinguish them from foci of pathologic lesions. A region that stained less intensely than the surrounding internal capsule was noted in tissue blocks from two normal brain specimens, corresponding in morphology and position to the signal-intensity changes seen on MR images. The properties of this focus suggest that it may represent fibers of the parietopontine tract.

Adolescent↗
PubMed1997

[Localization of the pyramidal tract in the internal capsule: relationship between CT classification of thalamic hemorrhage and motor weakness].

To better understand the pyramidal tract of the internal capsule, we evaluated the relationship between the localization of thalamic hemorrhage and motor weakness. On an axial CT scan at the level of the pineal body, two lines were drawn as follows: line-a between the lateral edge of the anterior horn and the lateral edge of the trigone, line-b vertical to the sagittal line and passing the midpoint of the third ventricle. The location of the hematoma was classified into three types according to localization of the center of the hematoma and lateral extension beyond line-a as follows: type A (anterior), type P (posterior) and type PL (postero-lateral). Discrepancy of motor weakness between upper extremities and lower extremities was higher in patients with hematoma of type P and type PL (p < 0.05) than in those with hematoma of type A. Improvement of motor weakness on discharge was higher in patients with type P (p < 0.01) than in those with type A. We concluded that most of the pyramidal tract fibers were located in the third quarter of the posterior limb of the internal capsule but a small number of pyramidal tract fibers were located in the anterior two-thirds of it. A greater number of cortico-spinal fibers to the upper extremities than to the lower extremities occupy the third quarter of the posterior limb of the internal capsule.

Adult↗
PubMed1986

[Pharmacological studies on Y-8894. (III). Its effect on the abnormal electrocorticogram induced by destruction of the internal capsule].

The effect of Y-8894 on the abnormal electrocorticogram (ECoG) of alcuronium-immobilized rats, induced by destruction of the internal capsule with heat, was compared with that produced by imipramine, amantadine and Ca-hopantenate. ECoG power in the delta + theta (1-7 Hz), alpha (7.5-12.5 Hz) and beta (13-30 Hz) bands was used as an index. Delta + theta power increased following destruction of the internal capsule with heat. The increased delta + theta power (abnormal ECoG) lasted for 60 min following the injection of saline at 60 degrees C for 3 min. Y-8894 (0.1-1 mg/kg, i.v.) apparently improved the abnormal ECoG dose-dependently by significantly reducing the increased delta + theta power. Similar results were obtained with amantadine (10 mg/kg, i.v.), but its potency was weaker than that of Y-8894. Imipramine (1 mg/kg, i.v.) and Ca-hopantenate (30 mg/kg, i.v.), however, both failed to modify the abnormal ECoG. All drugs, except Ca-hopantenate, decreased the magnitudes of the alpha and beta bands. The above results suggest that Y-8894 may be effective in ameliorating cerebral dysfunction induced experimentally by the lesion of the internal capsule.

Amantadine↗
PubMed1996

Transient neuronal population of the internal capsule in the developing human cerebrum.

The present study reveals the presence of a distinct group of cells, resembling reticular thalamic neurones, in the internal capsule during fetal development. This cell population rapidly decreases in size during early infancy and few cells are apparent in the 1-year-old infant. Internal capsule cells are well differentiated, multipolar or polymorphous, AChE (acetylcholinesterase)-reactive neurones. The following specific molecular markers were demonstrated in the neurones of the internal capsule: MAP2 (microtubule-associated protein 2), somatostatin, calbindin-D28K and p75 low-affinity NGF (nerve growth factor) receptor. A group of neurones described here corresponds to the perireticular thalamic nucleus found in certain mammalian species, hitherto unidentified in the primate brain, which may play an important role during development.

Acetylcholinesterase↗
PubMed1988

Contraversive circling elicited from the internal capsule and substantia nigra: evidence for a continuous axon bundle mediating circling.

Electrical stimulation of many brain sites (e.g., anteromedial cortex, internal capsule, substantia nigra, superior colliculus, rostro-medial tegmentum, and medial pons) evokes circling. The collision method of Shizgal et al. (J. Comp. Physiol. Psychol., 94 (1980) 227-237) was used to determine whether these sites are functionally connected for the production of circling in rats. If connectivity was evidenced, then refractory period and conduction velocity distributions were determined for axons passing through the connected stimulation sites. Collision of up to 90% was found between electrodes placed in internal capsule and substantia nigra, suggesting that these sites are connected by continuous axons that mediate circling. The refractory periods of these axons ranged from 0.5 to 4.5 ms, and the conduction velocities of these axons ranged from 0.9 to 4.4 ms. These velocities are similar to those of striatonigral axons. No collision was found between anteromedial cortex and any other sites tested, nor between pontine sites and internal capsule or substantia nigra.

Animals↗
PubMed2000

Intraoperative direct subcortical stimulation for identification of the internal capsule, combined with an image-guided stereotactic system during surgery for basal ganglia lesions.

BACKGROUND: The two main problems of surgery for basal ganglia lesions are: first, the difficulty of accurately localizing the lesion in this deep location; and second, the proximity to the internal capsule, with the risk of permanent postoperative sequelae. The author describes the use of intraoperative direct electrical subcortical stimulation in the identification and preservation of the internal capsule, combined with an image-guided stereotactic system for the selection of the best surgical approach in a case of deep cavernoma. CASE DESCRIPTION: A 33-year-old man was admitted to our institution with a history of three episodes of transitory left hemiparesia in the last 12 years. Neurological examination revealed a mild left weakness. Magnetic resonance imaging (MRI) showed typical features of a right posterior capsular-lentiform cavernoma. To prevent another hemorrhagic event, surgery was performed via a right transdistal sylvian approach, using a computer-assisted stereotactic method that allowed us to reach the lesion directly and direct stimulations to detect the subcortical pyramidal pathways. The patient had a transitory worsening with complete recovery in 10 days. Control MRI showed total resection. CONCLUSION: As described at the cortical level, the intraoperative direct subcortical stimulations seem also to represent an easy, safe, accurate, and reliable method of real-time functional identification of the internal capsule during surgery for basal ganglia lesions. The combination with an image-guided stereotactic system to accurately localize the lesion minimizes the risk of postoperative sequelae, and seems to warrant an increase of the surgical indications in this location.

Adult↗
PubMed1982

The site of motor corticospinal fibres in the internal capsule of man. A computerised tomographic study of restricted lesions.

The distribution of the motor impairment was correlated to the site and extension of the lesion of 18 patients with restricted lesions of the internal capsule, detectable with computerised tomography (CT). In three cases the lesion was located in the anterior limb of the internal capsule and the patients did not suffer any motor defect. Among the 15 patients with lesions in the posterior limb, 13 presented a distribution of the motor weakness consistent with a location of the corticobulbar fibres in the genu and corticospinal fibres in the anterior half of the posterior limb. Our CT study confirms the classical view on the location of the pyramidal tract in the internal capsule of man, but also evidences the possibility of individual variations.

Adult↗
PubMedDate not supplied

[Thalamic dementia due to infarct of the left thalamus and genum of the right internal capsule].

INTRODUCTION AND OBJECTIVES: Thalamic dementia is the clinical consequence of a disorder of both thalami. It is generally secondary to bilateral paramedial thalamic infarcts due to disorders of small blood vessels or cardioembolism. We report a case of dementia of acute onset involving the left thalamus and the genum of the right internal capsule. CLINICAL CASE: A 33 year old man, HIV positive, category B2, admitted to hospital for tuberculous meningitis presented with the acute onset of somnolence, followed by marked bradypsychism, personality changes, marked disorder of executive explicit memory without associated praxic, gnosic or language disorders. Ocular motility remained normal. There was left central facial paralysis with inverse emotive voluntary dissociation. The other cranial nerves were normal. There was left hemiparesia with extensor plantar reflex. No other alterations. Cerebral MR imaging was compatible with paramedial infarcts of the left thalamus and genum of the right internal capsule. CONCLUSIONS: Thalamic dementia generally occurs in bilateral paramedian thalamic disorders. There are cases of disorders of executive memory secondary to infarcts of the genum of the internal capsule due to interruption of the thalamotemporal pathways and a contralateral paramedial thalamic lesion.

Adult↗
PubMed1975

Location of human pyramidal tract in the internal capsule: anatomic evidence.

A patient with a small infarct located posteriorly in the internal capsule had 9 years of weakness of the contralateral face, arm, and leg. At necropsy, it was found that degeneration of the corticospinal tract was almost complete in the midbrain and medullary pyramid. This case supports the increasing evidence that the human pyramidal tract is located in the third quarter of the posterior limb of the internal capsule.

Brain Mapping↗
PubMed1992

[A case of chronic toluene intoxication with abnormal MRI findings: abnormal intensity areas in cerebral white matter, basal ganglia, internal capsule, brain stem and middle cerebellar peduncle].

We reported a case of 21 years old man of chronic toluene intoxication with abnormal intensity areas on MRI in cerebral white matter, basal ganglia, internal capsule (especially posterior limb), brain stem and middle cerebellar peduncle. The patient developed various neurological abnormalities such as blurred vision, ataxic speech, gaze evoked horizontal nystagmus, bilateral pyramidal tract sign and limb ataxia after 8 years sniffing of thinner (mainly toluene). MRI examination revealed diffuse high intensity areas in cerebral white matter on T1 weighted image. On T2 weighted image, high intensity areas of deep cerebral white matter, internal capsule (especially posterior limb), cerebral peduncle, ventral pons and middle cerebellar peduncle were noted. Basal ganglia (caudate nucleus, lenticular nucleus and thalamus) were displayed as low intensity area on T2 weighted image. These high intensity areas of internal capsule, brain stem and middle cerebellar peduncle on T2 weighted image would be significant for understanding pyramidal tract sign and cerebellar sign of this case. On the basis of neuropathological descriptions of chronic toluene intoxication, these high intensity areas of T2 weighted image were presumed to be demyelinating lesions of the central nervous system.

Adult↗