SYNAPTIC ORGANIZATION OF THE SUPERIOR COLLICULUS

上丘被认为是启动的关键结构。 眼睛和头部对视觉、听觉和视觉的定向反应 体感提示。它位于上丘的深层。 这些感官输入汇聚在一起。在深层还存在着 投射到脑干和脊髓区域的传出神经元，以及 从而影响眼睛和头部的方向。这些深层的纹状体 神经元在感觉-运动转换中起着关键作用，并且可以直接进入 去运动神经元池子里定向。他们的反应直接取决于 根据突触输入的数量、类型、分布和位置 他们。 深丘神经元受基底节的影响较大。它 已经确定基底神经节参与了 以及直接影响基底节的疾病 导致眼球和头部运动相关的障碍。基底节，在 特别是黑质，似乎施加了紧张性抑制 对深上丘细胞的影响。 这个项目直接解决了整合的解剖基础 深丘层中大传出细胞的特性 参与控制头部和眼睛的运动。使用组合 放射自显影、辣根过氧化物酶和免疫细胞化学技术 对于光学和电子显微镜，人们希望能准确地显示输入 从黑质到深丘神经元，再到 确定它们的抑制作用是由神经递质介导的 γ氨基丁酸(GABA)。还建议确定其他 大的传出丘神经元的抑制性输入来源 在定向方面。

The superior colliculus is recognized as a key structure in the initiation of orientation responses of the eyes and head to visual, auditory and somatosensory cues. It is in the deep layers of the superior colliculus that these sensory inputs converge. Also present in the deep layers are efferent neurons which project to areas of brainstem and spinal cord, and thus influence orientation of the eyes and head. These deep collicular neurons are pivotal in sensorimotor transformations and have direct access to the motoneuron pool for orienting. Their response is directly dependent upon the number, type, distribution and location of synaptic inputs upon them. Deep collicular neurons are strongly influenced by the basal ganglia. It is well established that the basal ganglia are involved in the initiation of movement, and diseases which directly affect the basal ganglia also cause eye and head movement-related disorders. The basal ganglia, in particular the substantia nigra, appear to exert a tonic inhibitory influence upon cells in the deep superior colliculus. This project directly addresses the anatomical basis for the integrative properties of large efferent cells in the deep collicular layers which are involved in the control of head and eye movements. Using combined autoradiographic, horseradish peroxidase and immunocytochemical techniques for light and electron microscopy, it is hoped to show precisely how inputs from substantia nigra teminate upon deep collicular neurons, and to establish that their inhibitory effect is mediated by the neurotransmitter gamma aminobutyric acid (GABA). It is also proposed to identify other sources of inhibitory input on large efferent collicular neurons involved in orientation.