PHYSIOLOGICAL ANALYSIS OF VOLUNTARY MOVEMENT

该项目的目标是更多地了解正常人和自愿运动障碍患者的运动控制，如帕金森氏病、小脑性共济失调、中风偏瘫和肌张力障碍。该科的一个主要科学目标是了解并可能影响患有先天性或获得性中枢神经系统损伤的患者的皮质重组。一种多模式方法(PET神经成像和功能磁共振、EEG和经颅磁刺激)正被用来确定个体卒中患者功能性脑电地形图的长期重组模式。对皮质下病变患者的数据分析表明，皮质活动和兴奋性模式的重新定位取决于内囊内病变的位置。脑电的频谱功率和相干分析被用来观察大脑在不同任务期间是如何沟通的。我们研究了EEG-EMG的一致性，以探索肌肉对运动皮质的控制。高频(14-50赫兹)的皮层-肌肉连贯性是由快速皮质脊髓束调节的，而低频(3-13赫兹)的连贯性可能是由皮质下节律发生器产生的。峰值相干值受作用力的影响不大。然而，当收缩强度增加到60%或更多时，伽马频段内的皮质-肌肉一致性出现。在较高的力量水平，这种伽马频段的一致性很可能反映了大脑皮层对运动单位的放电率调制的控制，并解释了肌肉Piper节律的产生，即最大收缩期间40赫兹的肌肉动作电位分组。在单手和双手任务中，大脑两侧感觉运动皮质之间的脑电连贯性相似，但当学习新的双手任务时，脑电一致性会短暂增加。在用fMRI进行的双手协调研究中，我们发现，在反平行运动中表现出明显比平行运动更多激活的区域是右侧SMA、双侧尾侧扣带运动区和右侧运动前皮质。我们还使用正电子发射计算机断层扫描和功能磁共振成像研究了运动学习的不同方面。使用PET，我们证实了先前的EEG发现，局灶性肌张力障碍患者初级感觉皮质的正常人类组织退化，支持感觉异常在肌张力障碍中起致病作用的概念。我们继续用肉毒杆菌毒素治疗局灶性肌张力障碍患者，并证明了A型抗体阳性的患者可以对F型做出反应。我们使用一种新的铁的MRI序列研究了一组F型共济失调患者，发现小脑齿状核中的铁含量增加，这与铁在病理生理学中重要的观点是一致的。-帕金森氏症、中风、肌张力障碍、脑电、正电子发射断层扫描、功能磁共振、共济失调、运动-人类受试者

The goal of this project is to learn more about the control of movement in normal humans and in patients with voluntary movement disorders such as Parkinsons disease, cerebellar ataxia, hemiplegia from stroke and dystonia. One major scientific target of the Branch is to understand and possibly influence cortical reorganization in patients with congenital or acquired lesions of the central nervous system. A multi- modality approach (neuroimaging with PET and functional MRI, EEG, and transcranial magnetic stimulation) is being used to determine patterns of long-term reorganization of functional brain topography in individual stroke patients. Analysis of data from patients with subcortical lesions indicated that the reoganization of the cortical activity and excitability patterns depends on the site of the lesion within the internal capsule. Spectral power and coherence analyses of EEG are being employed to see how the brain communicates during different tasks. We have looked at EEG-EMG coherence to explore the motor cortex control of muscle. The cortico-muscular coherence in the higher frequencies (14-50 Hz) is mediated by the fast corticospinal tract and that coherence in the lower frequencies (3-13 Hz) is probably generated by a subcortical rhythm generator. The peak coherence value was not significantly affected by the produced force. However, a cortical-muscular coherence within the gamma band appeared as the strength of contraction increased up to 60% or more. This gamma band coherence at the higher force level most likely reflects the cortical control of the firing-rate modulation of the motor units and explains the generation of the muscle Piper rhythm, the 40 Hz grouping of muscle action potentials during maximal contraction. EEG coherence between the sensorimotor cortices on the two sides of the brain is similar for unimanual and bimanual tasks, but increases transiently when a new bimanual task is learned. In a study of bimanual coordination using fMRI, we found that areas which showed significantly more activation with antiparallel than parallel movement were the right SMA, the caudal cingulate motor area bilaterally and the right lateral premotor cortex. We have also studied different aspects of motor learning using PET and fMRI. Using PET, we confirmed prior EEG findings that the normal homuncular organization of the primary sensory cortex is degraded in patients with focal dystonia supporting the concept that sensory abnormalities play a pathogenetic role in dystonia. We have continued to treat patients with focal dystonias with botulinum toxin and demonstrate that patients with antibodies to type A can respond to type F. We studied a group of patients with Friedreichs ataxia using a new MRI sequence for iron and demonstrated an increased iron content in the dentate nucleus of the cerebellum consistent with the idea that iron is important in the pathophysiology. - Parkinson's disease, stroke, dystonia, EEG, positron emission tomography, functional MRI, ataxia, movement - Human Subjects