Somatotopically located motor fibers in corona radiata: evidence from subcortical small infarcts

Using T2-weighted MRI, we measured the relative anteroposterior distance of small corona radiata infarcts in 54 patients who had disproportionate weakness in the bulbar (Group A), arm (Group B), and leg (Group C) muscles. The lesions were differently (p < 0.01) located: Group A, most were located anteriorly; Group B, most were in the middle; and Group C, most were located posteriorly. These results suggest that motor fibers are somatotopically arranged in the human corona radiata.     

Aberrant pyramidal tract in a patient with corona radiata infarct A diffusion tensor tractography study

The aberrant pyramidal tract refers to the collateral pathway of the pyramidal tract through the medial lemniscus in the brainstem.A 63-year-old male patient presented with severe paralysis of the left extremities due to a right corona radiata infarct.He was able to extend the affected fingers against resistance at 2 months after stroke onset.At 6 months after stroke onset,he was able to perform some fine motor activities,as well as to walk with a nearly normal gait.Functional MRI,which was performed at 6 months after onset,showed that the contralateral primary sensorimotor cortex was activated during affected(left) hand movements.Diffusion tensor tractography results showed that at 2 weeks after stroke onset,pyramidal tracts of the affected hemisphere originated from the primary motor cortex and descended along the known pathway of the pyramidal tract with an aberrant pyramidal tract,which was bypassed through the medial lemniscus from the midbrain to the lower pons.However,the pyramidal tract from midbrain to pons in the affected hemisphere could not be depicted by diffusion tensor tractography at 6 months after stroke onset;instead,only the aberrant pyramidal tract existed for the course of the disappeared pyramidal tract.Results from this study indicate that the main motor functions of the affected extremities appeared to be controlled via the aberrant pyramidal tract with degeneration of the pyramidal tract in the brainstem of the affected hemisphere.     

Magnetic resonance imaging of ataxic hemiparesis localized to the corona radiata

A 61-year-old woman developed right hemiparesis with homolateral cerebellar-type ataxia. Computed tomography and magnetic resonance imaging demonstrated left corona radiata lesions, not present on magnetic resonance imaging 1 year earlier. No brainstem lesions were identified, suggesting that ataxic hemiparesis can result from lesions in the corona radiata.     

Thalami and corona radiata in juvenile NCL (CLN3): a voxel-based morphometric study

Juvenile neuronal ceroid lipofuscinosis (CLN3) is characterized by progressive cerebral atrophy. The purpose of this study was to re-evaluate the three-dimensional magnetic resonance (3D-MR) images of patients with CLN3 using voxel-based morphometry (VBM) to achieve a detailed understanding of the affected brain regions. T1-weighted 3D-MR images of 15 patients with CLN3 (age range: 12–25 years, mean age 17.6 years) and 15 age- and sex-matched controls were analyzed using VBM. VBM showed strikingly focal alterations in the brains of CLN3 patients: the gray matter volume was significantly decreased in the dorsomedial part of the thalami of CLN3 patients. In addition, the volume of the white matter was significantly decreased in the corona radiata, containing cortical efferents and afferents in the transition between the internal capsule and the subcortical white matter. These data suggest that the dorsomedial part of the thalamus and the corona radiata may have a central, previously unrecognized role in the pathogenesis of CLN3.     

Assessment of the corona radiata sensory tract using awake surgery and tractography

Anatomical localization of brain function can be achieved by functional changes during awake surgery combined with tractography constructed by diffusion tensor imaging studies. We aimed to use these techniques to characterize the sensory tract in the corona radiata in patients with closely associated brain tumors. Of nine patients who had brain tumors in the primary sensory area (S1) and who underwent awake surgery between October 2004 and July 2007, two patients showed deterioration in deep sensation during and after awake surgery. Both of these patients also developed involuntary movements (for patient 1 this was myoclonus of the left hand, while patient 2 experienced unintentional lifting of the arm). In these two patients, tumors were located just beside the sensory tract in the corona radiata of the right hemisphere. In patient 2, Wallerian degeneration of the sensory tract and concomitant deterioration of superficial and deep sensation were observed at 6 months after awake surgery. These results suggest that damage to a closely associated sensory tract in the corona radiata is critical to the development of sensory deficits and involuntary movements. For patients who undergo surgical resection of S1 brain tumors, pre-operative tractography to detect the sensory tract in the corona radiata may allow protection of the sensory tract during awake surgery, thereby preventing post-operative sensory deficits.     

Ipsilateral hemiparesis caused by a corona radiata infarct after a previous stroke on the opposite side

Ipsilateral hemiparesis after a supratentorial stroke is rare. However, the role of the reorganization of the unaffected hemisphere in recovery after a stroke is poorly understood. Two patients developed ipsilateral hemiparesis after a left corona radiata infarct. Both of these patients had previously experienced contralateral hemiparesis after a right-sided supratentorial stroke. Functional magnetic resonance imaging demonstrated bilateral motor area activation during paretic left hand movement. This finding suggests that the ipsilateral hemiparesis was caused by a new stroke in the ipsilateral motor system that was functionally reorganized after the previous stroke.     

脑囊虫病诊断方法的探讨

为进一步探讨脑囊虫病的诊断方法,对43例具有中枢神经系统症状和体征的病人进行了脑部CT、血清和CSF囊虫抗体检查（ELISA法）,32例CT无典型脑囊虫病改变的患者做了脑MRI检查。结果11例（25．6％）CT表现为多发圆形低密度灶,部分间有点状钙化,为脑囊虫病的典型改变,余32例改变不典型或无异常改变。血清囊虫抗体阳性37例（86．0％）,CSF囊虫抗体阳性32例（74．0％）。27例（84．4％）脑MRI可见典型脑囊虫病改变,5例为非特异性改变。认为脑囊虫病的诊断应结合临床表现、免疫学检查结果和影像学改变综合分析,MRI对脑囊虫病的诊断价值优于CT。     

Clinical characteristics of infarction of the corona radiata adjacent to the body of the lateral ventricle

Fifty-three patients with infarction of the corona radiata adjacent to the body of the lateral ventricle were clinically evaluated in order to determine the clinical characteristics of this infarction and localization of the pyramidal tract in this area, as well as its somatotopy and etiology. Clinical characteristics included the following: (1) this type of infarction was observed in 9.1% of all patients with cerebral infarction; (2) although 81.1% of the patients of this type had clear consciousness and neuropsychological symptoms in some patients; (3) motor paralysis usually occurred in the upper limbs; (4) monoplegia occurred in 13.2% of patients, with monoplegia of upper and lower limbs being associated with infarction of the anterior and posterior portion, respectively, of the corona radiata adjacent to the body of the lateral ventricle; (5) pure motor hemiplegia was observed in 45.3% of patients; (6) facial paralysis and dysarthria were observed in 54.7% and 58.5% of patients, respectively, and the incidence of these symptoms was the highest in the infarction of the anterior portion of the corona radiata; (7) sensory disturbance, which was usually recognized as a mild subjective feeling of abnormality and localized to the limbs, was reported by 47.2% of patients; (8) risk factors included hypertension, diabetes and high hematocrit and triglyceride levels; (9) arteriosclerosis was often noted in areas between the siphon of the internal carotid artery and the main stem of the anterior and middle cerebral arteries; (10) 64.2% of patients were able to conduct independent activities of daily life (ADL) 1 month after the onset of the disease and more marked paralysis remained in the infarction of the middle portion than in the anterior or posterior portion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Medial reorganization of motor function in corona radiata following middle cerebral artery infarction A case report

Peri-lesional reorganization is one of the motor recovery mechanisms following stroke. A 23-year-old female who presented with complete paralysis of the right extremities at the onset of infarct in the left middle cerebral artery territory was included. She slowly recovered some function, and could extend the affected knee with resistance after 9 months. Diffusion tensor tractography, functional MRI, and transcranial magnetic stimulation testing were performed at 7 years after onset. Results showed that diffusion tensor tractography of the affected （left） hemisphere passed through the medial corona radiata at, or around, the wall of the lateral ventricle. The contralateral primary sensorimotor cortex was activated during affected knee movements. The motor-evoked potential, which was obtained from the affected leg, exhibited corticospinal tract characteristics. Results indicated that motor function of the affected leg recovered via the corticospinal tract, which descended through the corona radiata medial to the infarct. The motor function of the affected leg was reorganized to the medial corona radiata following infarct to the middle cerebral artery territory.     

Acute pseudobulbar syndrome. Bilateral infarction of the junction of the internal capsule with the corona radiata

A 33 year-old hypertensive woman presented with a pure, acute, pseudobulbar palsy, two years after a right transient facio-brachial hemiplegia. C.T. scan showed two areas of low density projecting over the junction of the internal capsule with the corona radiata, at the external border of the lateral ventricles. They involved the territories of both posterolateral choroidal arteries, at the junction with those of the external lenticulostriatal arteries. Clinical data, clinico-pathological correlations in pseudobulbar palsies, and new concepts about the corticobulbar tract anatomy are discussed with evidence from this case.     

Localization of orofacial representation in the corona radiata,internal capsule and cerebral peduncle in Macaca mulatta

Subcortical white matter injury is often accompanied by orofacial motor dysfunction, but little is known about the structural substrates accounting for these common neurological deficits. We studied the trajectory of the corticobulbar projection from the orofacial region of the primary (M1), ventrolateral (LPMCv), supplementary (M2), rostral cingulate (M3) and caudal cingulate (M4) motor regions through the corona radiata (CR), internal capsule (IC) and crus cerebri of the cerebral peduncle (ccCP). In the CR each pathway was segregated. Medial motor area fibers (M2/M3/M4) arched over the caudate and lateral motor area fibers (M1/LPMCv) curved over the putamen. At superior IC levels, the pathways were widespread, involving the anterior limb, genu and posterior limb with the M3 projection located anteriorly, followed posteriorly by projections from M2, LPMCv, M4 and M1, respectively. Inferiorly, all pathways maintained this orientation but shifted posteriorly, with adjacent fiber bundles overlapping minimally. In the ccCP, M3 fibers were located medially and M1 fibers centromedially, with M2, LPMCv, and M4 pathways overlapping in between. Finally, at inferior ccCP levels, all pathways overlapped. Following CR and superior IC lesions, the dispersed pathway distribution may correlate with acute orofacial dysfunction with spared pathways contributing to orofacial motor recovery. In contrast, the gradually commixed nature of pathway representation inferiorly may enhance fiber vulnerability and correlate with severe, prolonged deficits following lower subcortical and midbrain injury. Additionally, in humans these findings may assist in interpreting orofacial movements evoked during deep brain stimulation, and neuroimaging tractography efforts to localize descending orofacial motor pathways.     

Clinical study of 227 patients with lacunar infarcts

We describe an analysis of 227 patients with lacunar infarcts; 177 were inpatients and the remaining 50 were outpatients. The group comprised 11% of all inpatients with cerebrovascular pathology and 16% of all consecutive inpatients with brain infarcts studied at the Department of Neurology of the Hospital de la Santa Creu i Sant Pau. The main risk factors identified in these patients were arterial hypertension in 164 (72%), diabetes mellitus in 64 (28%), and heart disease in 58 (26%). The most common clinical syndromes were pure motor hemiparesis in 125 (55%), pure hemisensory stroke in 42 (18%), the sensorimotor deficit syndrome in 34 (15%), ataxic hemiparesis in seven (3%), and the dysarthria-clumsy hand syndrome in four (2%); atypical syndromes were observed in 15 patients (7%). Lacunes were demonstrated by computed tomography in 100 patients (44%) and by magnetic resonance imaging in 35 (78%) of the 45 patients in which it was applied. Magnetic resonance imaging was significantly better (p less than 0.001) than computed tomography for imaging lacunes, especially those located in either the pons (p less than 0.005) or the internal capsule (p less than 0.001). After the acute phase, mild or no neurologic disability was detected in 178 patients (78.4%), moderate disability persisted in 48 patients (21.1%), and severe disability was recorded in one case (0.4%). Lacunar infarcts are a clearly defined entity with characteristic clinical features and an excellent short-term prognosis. Magnetic resonance imaging is the current method of choice for demonstrating these small brain lesions.     

Clinical study of lacunar infarcts in non-hypertensive patients

Lacunar infarcts in non-hypertensive patients have been scantly assessed. The objective of this study was to determine clinical features of lacunar infarct in patients without hypertension (n = 91) in comparison with characteristics of lacunar infarcts occurring in patients with hypertension (n = 283) collected from a prospective hospital-based stroke registry in which 2000 patients with acute stroke are included. Predictors of lacunar infarct in patients without hypertension were assessed by multiple logistic regression analysis. The group of non-hypertensive patients with lacunar infarction showed a significantly higher frequency of male gender, age 85 years or older, history of atrial fibrillation, chronic obstructive pulmonary disease and diabetes mellitus, and a significantly lower frequency of female gender and absence of limitation at hospital discharge than hypertensive patients with lacunar infarct. Differences between hypertensive and non-hypertensive patients in relation to frequency of the different lacunar syndromes were not observed. After multivariate analysis, age 85 years or older (odds ratio 3.13), diabetes (odds ratio 2.57), and male gender (odds ratio 1.99) seemed to be independent factors associated with lacunar infarct in patients without hypertension. Lacunar infarct in non-hypertensive patients showed some differential clinical features compared to the remaining lacunar infarctions because it occurred more frequently in male patients aged 85 years or older. In this group, diabetes was the most important modificable risk factor. These results suggest an ealier effect of arteriopathy caused by hypertension favoring lacunar brain ischemia, whereas in non-hypertensive patients, arteropathy responsible for small vessel disease would take a more prolonged time in causing lacunar infarction.     

侧脑室体旁放射冠区脑梗塞的临床和CT对照分析

报告经头颅CT扫描证实的侧脑室体旁放射冠区脑梗塞84例,其中腔隙性脑梗塞(Lacunae infarction,LI)59例,分水岭梗塞(Watershed infarction,WI)25例。结合文献就两者的病因,临床特征和放射冠区传导束的排列情况进行了讨论,结果发现高血压是二者共同的、主要的病因,放射冠区锥体束的排列顺序与躯体存在定位关系。     

Transcallosal motor pathway from affected motor cortex to affected hand in a patient with corona radiata infarct A diffusion tensor tractography and transcranial magnetic stimulation study

The mechanisms of motor recovery through the transcallosal pathway remain poorly understood.The present study reports on a hemiplegic patient with corona radiata infarct; it attempts to confirm motor recovery through the transcallosal motor pathway, from the affected motor cortex to the affected hand, using diffusion tensor tractography and transcranial magnetic stimulation. A 54-year-old, male patient and eight age-matched, normal subjects were enrolled in the study. The patient's right hand was initially completely paralyzed, but slowly recovered over 6 months. In the control subjects and the unaffected hemisphere (right) of the patient, the corticospinal tracts originated from the motor cortex and descended along the known corticospinal tract pathway.However, the corticospinal tract of the affected hemisphere was disrupted at the upper pons.Following transcranial stimulation of the affected (left) motor cortex, motor evoked potential from the affected (right) abductor pollicis brevis muscle exhibited longer latency than opposite motor evoked potential. Results from the present study suggest that motor function of the affected (right) hand recovered via the transcallosal motor pathway from the affected (left) motor cortex in this patient.