Locomotor Adaptation Is Associated with Microstructural Properties of the Inferior Cerebellar Peduncle

The Cerebellum - In sensorimotor adaptation paradigms, participants learn to adjust their behavior in response to an external perturbation. Locomotor adaptation and reaching adaptation depend on...     

Integrity of the Inferior Cerebellar Peduncle Correlates with Ambulatory Function after Hemorrhagic Stroke

ObjectivesCerebro-cerebellar connectivity plays a critical role in motor recovery after stroke; however, the underlying mechanism of walking recovery is unclear. The dorsal spinocerebellar pathway has been suggested as a biomarker of poststroke ambulatory function. We aimed to explore the association between ambulatory function and the dorsal spinocerebellar pathway's integrity after intracerebral hemorrhage (ICH).Materials and methodsTwenty-seven patients with ICH who were admitted for inpatient rehabilitation during the subacute phase of stroke and 27 age-matched healthy controls were included retrospectively. Ambulatory function was assessed using the Berg Balance Scale and Mobility score. We measured the fractional anisotropy (FA) values of the corticospinal tract (CST) and inferior cerebellar peduncle (ICP) as the final route of the dorsal spinocerebellar pathway. The FA laterality indices, representing the degree of degeneration, were calculated. A Spearman correlation analysis and multivariate linear regression models were used to determine the associations between the FA laterality indices and ambulatory function.ResultsAn FA reduction was found in both the ipsilesional CST and contralesional ICP of the patients. The ICP FA laterality index exhibited a moderate correlation with ambulatory function (Berg Balance Scale, ρ_BBS=0.589; Mobility score, ρ_MS=0.619). On dividing the patient group into the moderate (mRS 3, 4) and severe disability (mRS 5) groups, a stronger correlation was found (ρ_BBS=0.777, ρ_MS=0.856, moderate disability; ρ_BBS=0.732, ρ_MS=0.797, severe disability). The ICP FA laterality index and age were independently associated with the Mobility score (R²=0.525).ConclusionsICP degeneration occurs after ICH, and its degree is associated with ambulatory function after ICH.     

Abnormalities in Myelination of the Superior Cerebellar Peduncle in Patients with Schizophrenia and Deficits in Movement Sequencing

Deficits in the execution of a sequence of movements are common in schizophrenia. Previous studies reported reduced functional activity in the motor cortex and cerebellum in schizophrenic patients with deficits in movement sequencing. The corticospinal tract (CST) and superior cerebellar peduncle (SCP) are fiber tracts that are involved in movement sequencing. However, the integrity of these tracts has not been evaluated in schizophrenic patients with respect to the performance of movement sequencing yet. Diffusion tensor magnetic resonance images (DT-MRI) were acquired from 24 patients with schizophrenia and 23 matched control subjects. Tractography was applied to reconstruct the CST and SCP and DT-MRI-specific parameters such as fractional anisotropy (FA) and radial diffusivity (RD) were reported. The patient group was further subdivided based on the score of sequencing of complex motor acts subscale of the Neurological Evaluation Scale into those with deficits in sequencing motor acts, the SQ^abn group (n?=?7), and those with normal performance, the SQ^norm group (n?=?17). Schizophrenia patients of the SQ^norm subgroup had significantly reduced FA and increased RD values in the right CST in comparison to the control group; the SQ^abn subgroup did not differ from the controls. However, the SQ^abn subgroup showed impaired integrity of the left SCP, whereas the SQ^norm subgroup did not. Abnormalities in the right CST in the SQ^norm and in the left SCP in SQ^abn groups suggest that the patients with SQ^abn represent subgroups with distinct deficits. Moreover, these results demonstrate the involvement of the SCP in the pathogenesis of movement sequencing in schizophrenia.     

Altered Microstructural Connectivity of the Superior Cerebellar Peduncle is Related to Motor Dysfunction in Children with Autistic Spectrum Disorders

Many studies have reported motor impairments in autistic spectrum disorders (ASD). However, the brain mechanism underlying motor impairment in ASD remains unclear. Recent neuroimaging studies have suggested that underconnectivity between the cerebellum and other brain regions contributes to the features of ASD. In this study, we investigated the microstructural integrity of the cerebellar pathways, including the superior, middle, and inferior cerebellar peduncles, of children with and without ASD by using diffusion tensor imaging (DTI) tractography to determine whether the microstructural integrity of the cerebellar pathways is related to motor function in children with ASD. Thirteen children with ASD and 11 age-, gender-, handedness-, and IQ-matched typically developing (TD) controls were enrolled in this study. DTI outcome measurements, such as fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD), for the cerebellar pathways were calculated. The Movement Assessment Battery for Children 2 (M-ABC 2) was used for assessing motor functions. There were no significant differences between the two groups in RD. However, compared to the TD subjects, patients with ASD had a significantly lower FA in the right superior cerebellar peduncle and lower AD in the left superior cerebellar peduncle, in addition to a significantly lower score in ball skills and the total test score of M-ABC 2. There was a significant positive correlation between the total test score of M-ABC 2 and FA in the right superior cerebellar peduncle in the ASD group. These findings suggest that the altered microstructural integrity of the superior cerebellar peduncle may be related to motor impairment in ASD.     

Brainstem auditory evoked potentials in Chiari-II malformation

Brainstem function in patients with Chiari-II malformation was evaluated by brainstem auditory-evoked potentials (BAEPs). All cases had associated hydrocephalus, some of which were shunted. The effect of the shunting operation on the wave forms was examined as well as the age-wave relationships. Although the shunting operation resulted in shortened brainstem conduction time, the overall postshunt responses were still far from normal. Another significant finding was that whereas there were remarkable abnormalities in recorded wave-forms in cases younger than 8 years, normal or almost normal responses were obtained in all cases older than 8. BAEP abnormalities could not be correlated with the severity of meningomyelocele, nor was the predictive value of response in assessing potential risk of symptomatic Chiari malformation established.This paper was presented at the 15th Annual Meeting of the International Society for Pediatric Neurosurgery, New York, July 12–16, 1987     

Reduced Cerebellar Inhibition in Migraine with Aura: A TMS Study

Subtle clinical cerebellar alterations have been found in migraine. Moreover, abnormalities in visual and motor cortex excitability consistent with a lack of inhibitory efficiency have been described in migraine, and it is known that cerebellum exerts an inhibitory control on cerebral cortex. Here, we investigated if impairment of cerebellar activity on motor cortex, i.e. reduced inhibitory control, can be found in migraine. Ten migraineurs with aura and seven healthy controls underwent a transcranial magnetic stimulation (TMS) protocol to investigate the cerebellar inhibitory drive on motor cortex: a conditioning pulse on right cerebellar cortex was delivered 5, 7, 10, 15 ms before a test stimulus (TS) on contralateral motor cortex. The cerebellar conditioning stimulus inhibits the size of the motor-evoked potential (MEP) produced by the TS alone by approximately 30–50%. Amplitude of MEP to TS alone showed no significant difference between patients and controls. Cerebellar conditioning TMS showed a significant deficit of cerebellar inhibition in migraine patients as compared to controls at all interstimulus intervals (5–15 ms) tested. Cerebellar inhibition is reduced in migraineurs. This could account, at least in part, for the reduced inhibitory efficiency previously showed in cerebral cortex of these patients.     

Evolution of Crossed Cerebellar Diaschisis in Middle Cerebral Artery Infarction

To elucidate the evolution of crossed cerebellar diaschisis, cerebral oxygen metabolism was measured repeatedly by positron emission tomography (PET) in 35 consecutive patients with unilateral cerebral infarction within the territory of middle cerebral artery. The crossed cerebellar diaschisis was defined as significant when the laterality ratio of cerebral oxygen metabolism between the left and right cerebellar hemispheres exceeded the control range (mean ± 2 standard deviations) as derived from 27 age-matched normal volunteers. Significant crossed cerebellar diaschisis was observed in 31 patients (89%) on the initial PET studies. Of these 31 patients, 23 with infarcts involving the frontal sensorimotor cortex persistently had crossed cerebellar diaschisis up to 5 years after onset, whereas the diaschisis disappeared in 8 patients with smaller infarcts mainly in the frontal or parietal lobe without recovery of oxygen metabolism in the infarcted areas. These present results suggest that crossed cerebellar diaschisis can exist persistently even in the late stage in those having a lesion involving the cortical pontine-cerebellar pathways.     

Ruptured Intrameatal Aneurysm of the Anterior Inferior Cerebellar Artery Accompanying an Arteriovenous Malformation: a Case Report

The distal anterior inferior cerebellar artery (AICA) aneurysms located inside the internal auditory canal are rare. The association of the distal AICA aneurysms and an arteriovenous malformation (AVM) on the same arterial trunk is exceptional. Eight reports of a total of ten cases have been published and all of the reported aneurysms were located in the meatal or postmeatal segment of the AICA. Herein, we report a case of ruptured aneurysm in the intrameatal portion of the AICA accompanying an AVM fed by the same artery. A 55-year-old man suffering from subarachnoid hemorrhage due to a ruptured intrameatal aneurysm with a small AVM underwent surgical trapping of the meatal loop, resulting in uneventful recovery. Follow-up angiography demonstrated neither aneurysm nor residual AVM nidus. We propose that trapping of the meatal loop could be a safe and feasible alternative to unroofing followed by neck clipping in selected patients with an intrameatal aneurysm of the AICA. We also review here the relevant literature.     

Chiari畸形并脊髓空洞的治疗与小脑扁桃体下疝分型

目的探讨Chiari畸形并脊髓空洞手术中,下疝的小脑扁桃体下舌分型与切除的标准。方法术中显微镜下观察32例下疝的小脑扁桃体压迫延髓的部位及其关系,结合MRI,提出下疝的小脑扁桃体分型,并根据分型切除小脑扁桃体下舌,切开脊髓中央管开口隔膜或活瓣,恢复第四脑室内脑脊液循环通畅。结果小脑扁桃体分型：①根据压迫部位分为：后方型27例,侧方型4例,侧前方型1例;②根据小脑扁桃体下疝程度分为：单侧压迫型11例,双侧压迫型21例。术后随访28例,MRI检查示下疝的小脑扁桃体均消失,第四脑室内脑脊液循环通畅,脊髓空洞明显缩小和消失;术后病人临床症状大多改善。结论下疝的小脑扁桃体根据其分型并切除,可为手术治疗Chiari畸形并脊髓空洞提供标准及依据。     

Extensive Cerebellar Venous Malformation Associated with a Varix and Cavernous Malformations: a Case Report

Venous malformations are the most common cerebral vascular malformation, frequently associated with cavernous malformation, and rarely accompanied by a varix. We report the case of a 67-year-old woman with tinnitus, whose cranial magnetic resonance images and selective catheter angiograms showed extensive cerebellar venous malformation with cavernous malformations and varix. Injury of vessel walls by increased blood flow in the draining vein of the malformation may have led to the development of cavernous malformations and a varix. To our knowledge, such association with an extensive cerebellar venous malformation has not been reported.     

Anomalous Origin of the Middle Meningeal Artery from the Posterior Inferior Cerebellar Artery

Various anastomosis and aberrant origins of the middle meningeal artery (MMA) have been documented in literature. However, there has been no report of its origin from the posterior inferior cerebellar artery (PICA) or its branches. In this report, we discuss an anomalous origin of the MMA from the PICA. Also, we discuss the embryological and anatomical development of the MMA. Imaging identification of the origin of the MMA is important while planning surgical and endovascular interventions in the region of the skull base.     

Demonstration of Recovery of a Patient with a Cerebellar Peduncle Injury due to Intracerebral Hemorrhage: a Diffusion Tensor Imaging Study.

背景：扩散张量成像可以对小脑脚进行三维显影。 目的：采用扩散张量成像,观察一位由于颅内出血所致小脑脚损伤患者在三个月内的功能恢复。 设计,时间和地点：病例研究,2008年10月至2009年3月期间在岭南大学医学院理疗康复教研室进行。 受试者：一位72岁女性患者,九名对照者,对照者同患者的年龄和性别相符。 方法：采用1.5T敏感性编码头线圈进行扩散张量成像。 主要观察指标：采用DTI-Studio软件评价小脑脚,包括小脑上脚,小脑中脚和小脑下脚。 结果：患者在发病三周后不能平坐,但可以独立行走,发病后4周可以完成大部分日常活动。3周扩散张量成像显示,所有小脑脚被血肿压迫。左小脑脚的后侧缩短,尤其是左小脑中脚在中部阻断。4月扩散张量成像显示,所有被压缩的小脑脚复原。此外,3周扩散张量成像结果还显示,除去右小脑中脚之外,所有小脑脚的各项异性值同正常对照值相比,降低了2个标准差。4月扩散张量成像结果显示,右小脑小脚的各项异性值有所增加,比正常对照值高出2个标准差。尽管如此,其他小脑脚的各项异性值仍保持在正常对照值之下的2个标准差。结果显示,发病后3周时的小脑脚的神经元损伤（所有小脑上脚,左小脑中脚和所有小脑下脚）在发病后4月内康复不明显。 结论：患者的功能性恢复最初是由于被压迫的小脑脚的减压所致,而不是受伤小脑脚的恢复。笔者认为采用扩散张量成像评价小脑脚对小脚损伤的疑似病例有帮助。     

Malformation of the Posterior Cerebellar Vermis Is a Common Neuroanatomical Phenotype of Genetically Engineered Mice on the C57BL/6 Background

C57BL/6 mice exhibit spontaneous cerebellar malformations consisting of heterotopic neurons and glia in the molecular layer of the posterior vermis, indicative of neuronal migration defect during cerebellar development. Recognizing that many genetically engineered (GE) mouse lines are produced from C57BL/6 ES cells or backcrossed to this strain, we performed histological analyses and found that cerebellar heterotopia were a common feature present in the majority of GE lines on this background. Furthermore, we identify GE mouse lines that will be valuable in the study of cerebellar malformations including diverse driver, reporter, and optogenetic lines. Finally, we discuss the implications that these data have on the use of C57BL/6 mice and GE mice on this background in studies of cerebellar development or as models of disease.