Structural Organization of the Superior Colliculus

超出所提供的空间。神经生物学面临的最大挑战之一是了解感觉和运动系统如何整合以产生行为。具有感觉和运动特性的细胞并置使得上级丘成为研究这一过程的富有成效的模型。通过应用上级丘研究的新方法，包括体外全细胞膜片钳记录和光刺激，我们首次在细胞水平上分析了连接其感觉和运动功能的内在电路。通过在记录过程中用神经元示踪剂填充细胞，并通过用逆行转运的示踪剂预先标记它们，它们的生理学与它们的形态和连接相关。=使用这种方法，我们证明了编码视觉刺激位置的表面丘层向更深层的前运动细胞发送兴奋信号，该前运动细胞产生视觉引导的注视方向转移的命令。前运动层也接受密集的胆碱能输入，这种输入来自同一个脑干细胞，脑干细胞调节感觉信息通过丘脑的视觉部分流向皮层。我们的第一个具体目标是测试的想法，这种胆碱能输入协调的感觉信号传输到皮层的启动定向运动朝向视觉刺激的增强。我们的第二个具体目标是测试的想法，即通过长距离抑制调制的前运动活动-之间的右和左丘和之间的吻固定和尾凝视转移神经元-允许激活的前运动细胞，命令头部和眼睛运动朝向视觉刺激在一个方向，而衰减的前运动细胞的活动，将命令竞争运动朝向其他方向的刺激。这些实验将有助于我们了解正常和患病大脑的感觉运动功能。性能现场=

EXCEED THE SPACE PROVIDED. One of the great challenges in neurobiology is to understand how sensory and motor systems are integrated to produce behavior. The juxtaposition of cells with sensory and motor properties has made the superior colliculus a fruitful model for studying this process. By applying methods new to the study of the superior colliculus, including in vitro whole-cell patch-clamp recording and photostimulation, we are analyzing for the first time at the cellular level the intrinsic circuitry that links its sensory and motor functions. By filling the cells during recording with neuronal tracers and by pre-labeling them with retrogradely transported tracers, their physiology is correlated with their morphology and connections. =Using this approach, we demonstrated that the superficial collicular layer, which encodes the location of visual stimuli, sends excitatory signals to a deeper layer of premotor cells, which generates commands for visually guided shifts in the direction of gaze. The premotor layer also receives a dense cholinergic input that arises from the same brainstem cells that modulate the flow of sensory information through the visual part of the thalamus to the cortex. Our first Specific Aim is to test the idea that this cholinergic input coordinates the enhancement of sensory signals transmitted to the cortex with the initiation of orienting movements toward visual stimuli. Our second Specific Aim is to test the idea that modulation of premotor activity by long-range inhibition - between the right and left colliculi and between rostral fixation and caudal gaze shifting neurons - permits the activation of premotor cells that command head and eye movements toward visual stimuli in one direction while attenuating the activity of premotor cells that would command competing movements toward stimuli in other directions. These experiments will contribute to our understanding of sensorimotor functions in the normal and diseased brain. PERFORMANCE SITE ========================================Section End===========================================