Neural circuitry for precise hand movements

进行了解剖学和生理学实验，以了解控制精确手部运动的大脑机制。研究了脊髓、基底神经节或大脑皮层的神经回路.应用逆行三标记技术分析了支配尺神经、正中神经和桡神经的运动神经元的分布。屈肌和伸肌运动神经元重叠明显.在皮层内微刺激映射后，研究了运动前皮层区到初级运动皮层后肢区域的输入组织。讨论了手和脚在初级运动皮层的表征差异.采用电生理和解剖学相结合的方法研究了与手部运动相关的皮质纹状体和纹状体/黑质投射.从纹状体补丁隔室传出投射后，揭示μ阿片受体表达神经元的银浸渍的目标。结果表明，手区纹状体斑片神经元的轴突主要分布于苍白球、脚内核、黑质的网状部和延髓部.在纹状体-脚内核通路中与前肢运动相关的多突触神经传递在表达P物质受体的纹状体中间神经元消融后使用单单位记录进行分析。纹状体中间神经元在维持基底神经节回路的空间特异性方面发挥重要作用.研制了超声引导下脑深部结构注射系统和荧光数字宏观成像系统。

Anatomical and physiological experiments were carried out to understand the brain mechanism for the control of precise hand movements. The neural circuitry in the the spinal cord, the basal ganglia, or the cerebral cortex was studied as follows.1. Distribution of the motoneurons innervating ulnar, median or radial nerves was analyzed using retrograde triple labeling technique. Overlap of flexor and extesor motoneurons were clearly demonstrated.2. Input organization of premotor cortical areas into the hindlimb region of the primary motor cortex was investigated after intracortical microstimulation mapping. Difference between hand and foot representations in the primary motor cortex was discussed.3. Corticostriatal and striatopallidal/nigral projections related to the hand movements were studied using combined electrophysiological and anatomical examination.4. Efferent projections from the striatal patch compartments were revealed after targeting of mu-opioid receptor expressing neurons followed by silver impregnation. It wa revealed that striatal patch neurons in the hand area send their axons to the globus pallidus, entopeduncular nucleus, and the pars compacta and reticulata of the substantia nigra.5. Polysynaptic neurotransmission in the striato-entopeduncular pathway related to the forelimb movements was analyzed using single-unit recording after ablation of striatal interneurons expressing substance P receptors. The striatal interneurons were shown to play importamt roles to maintain spatial specificity in the basal ganglia circuitry.6. Both injection system for deep brain structures under guidance of ultrasonography, and photographic system for fluorescence digital macrography were developed to carry out these experiments.