Structural Organization of the Superior Colliculus

超出提供的空间。神经生物学的最大挑战之一是了解感觉和运动系统是如何整合在一起产生行为的。具有感觉和运动特性的细胞并列，使上丘成为研究这一过程的一个富有成效的模型。通过将新的方法应用于上丘的研究，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，并用逆行运输的示踪剂预先标记细胞，它们的生理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浅丘层向更深层次的运动前细胞发送兴奋信号，后者产生视觉引导的凝视方向转移的命令。运动前层还接受密集的胆碱能输入，这种输入来自相同的脑干细胞，这些细胞调节感觉信息流，通过丘脑的视觉部分到达皮质。我们的第一个具体目标是测试这样一种想法，即这种胆碱能输入与向视觉刺激定向运动的启动协调了传递到大脑皮层的感觉信号的增强。我们的第二个具体目标是测试这样一种想法，即通过长时间的抑制-在右侧和左侧丘脑之间以及在头端固定和尾部凝视移动神经元之间-允许激活控制头部和眼睛朝着一个方向的视觉刺激移动的运动前细胞，同时减弱将命令朝着其他方向的竞争运动的运动前细胞的活动。这些实验将有助于我们理解正常和疾病大脑中的感觉运动功能。表演网站========================================Section End===========================================

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===========================================