Neural Control of a Complex Oculomotor Plant

复杂动眼植物的神经控制

• 批准号: 7104952
• 负责人: Joel M Miller
• 金额: $ 47.68万
• 依托单位: SMITH-KETTLEWELL EYE RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-10 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7104952
• 关键词: Macaca mulatta; biomechanics; connective tissue; electrostimulus; eye movements; magnetic resonance imaging; motor neurons; muscle; muscle contraction; neuroregulation; oculomotor nerve; oculomotor nuclei

DESCRIPTION (provided by applicant): Significance: Almost 40 years of oculomotor physiology have been based on the powerful simplifying notion that the oculomotor nuclei, their cranial nerves, and the extraocular muscles (EOMs) constitute a simple, homogeneous Final Common Path (FCP), in which supernuclear signals controlling the several types of eye movement combine anonymously. It was, therefore, surprising when studies of vergence eye movement using direct muscle force measurements and magnetic resonance imaging (MRI) failed to confirm predictions that would follow from earlier, well-replicated motoneuron (MN) studies, if the FCP hypothesis were correct. This hypothesis now appears untenable, and the oculomotor plant ripe for exploration of its long-neglected functional richness. Supernuclear disorders are mostly inaccessible to treatment, whereas functions localized to the oculomotor periphery may be readily subject to pharmacologic, surgical and genetic manipulations. An understanding of related motoneuron and muscle fiber specializations would make it possible to effect subtle changes, compared to the gross manipulations of muscle action currently available to treat strabismus and related disorders. Studies: Our first overall aim is to delineate failures of the FCP hypothesis: (1) We will strongly verify the "missing lateral rectus (LR) force paradox" by recording identified abducens MNs and simultaneously measuring LR forces in vergence, continuing (2) to distinguish changes in slopes and Y-intercepts of MN rate-position curves, and to study the variation of LR and medial rectus (MR) convergence forces across the horizontal gaze plane. (3) We will replicate in monkeys, an MRI study in humans that found no globe retraction in convergence, and will extend it using "gold bead fiducials" (GBFs) to visualize orbital contents. (4) Using our muscle force transducers (MFTs) we will determine if LR and MR forces are consistent with globe translation, muscle paths and connective tissue movements observed with GBFs. Our second overall aim is to characterize complex articulations of the oculomotor plant. (5) We will determine if decreases in LR path length offset the convergence-related increase in contractile force predicted by the MN studies. (6) We will microstimulate MNs and use GBFs to visualize globe, pulley and other tissue movements, (7) determine if MN recruitment order varies with vergence state, and (8) if muscle forces vary with fixation accuracy. (9) We will study EOM unit summation in-vivo using multi-electrode stimulation and MFTs.

DESCRIPTION (provided by applicant): Significance: Almost 40 years of oculomotor physiology have been based on the powerful simplifying notion that the oculomotor nuclei, their cranial nerves, and the extraocular muscles (EOMs) constitute a simple, homogeneous Final Common Path (FCP), in which supernuclear signals controlling the several types of eye movement combine anonymously. 因此，当使用直接肌肉力量测量和磁共振成像（MRI）对GRGENCE眼运动进行研究时，如果FCP假设正确，则无法确认将从早期的，良好复式的Motoneuron（MN）研究进行的预测。 现在，该假设似乎是站不住脚的，并且动眼植物成熟，以探索其长期被忽略的功能丰富性。 超核疾病大多是无法治疗的，而本地局部到动眼处外部的功能可能很容易受到药理，外科手术和遗传操作的约束。 与目前可用于治疗斜视和相关疾病的肌肉作用的严重操纵相比，对相关运动神经元和肌肉纤维专业的理解将有可能实现微妙的变化。 研究：我们的第一个总体目的是描述FCP假设的失败：（1）我们将通过记录鉴定出的裸露的MN并同时测量Vergence中的LR力量，以区分（2）区分MMN的变化，并确定速度的变化，并确定依次的变化，并测量速度的变化。直肌（MR）跨水平凝视平面的收敛力。 （3）我们将在猴子中复制，这是一项在人类中的MRI研究，该研究没有发现收敛的地球缩回，并将使用“金珠信托”（GBF）（GBFS）将其扩展，以可视化轨道含量。 （4）使用我们的肌肉力传感器（MFT），我们将确定LR和MR力是否与GBF观察到的球形翻译，肌肉路径和结缔组织运动一致。 我们的第二个总体目的是表征动眼植物的复杂发音。 （5）我们将确定LR路径长度的减小是否抵消了MN研究预测的收缩力的收缩力增加。 （6）我们将微刺激MN，并使用GBF可视化地球，皮带轮和其他组织运动，（7）确定MN募集顺序是否随Gergence状态而变化，并且（8）如果肌肉力量随固定精度而变化。 （9）我们将使用多电极刺激和MFT研究EOM单位求和。