SENSORY AND MOTOR INTEGRATION IN THE SPINAL CORD

描述（由申请人提供）：脊髓中的神经元网络，称为中枢模式发生器（CPGs），具有相当大的运动能力，可以通过皮肤刺激激活脊髓完全横断的脊椎动物。CPGs在脊椎动物模型系统中产生协调的运动输出与神经肌肉阻滞固定。固定化脊龟产生混合协同吻侧划痕、常规协同口袋划痕和常规协同屈曲反射的运动模式。在吻侧划伤中，单关节膝关节伸肌在髋屈肌活动中活跃；在口袋划伤中，单关节膝关节伸肌在髋关节伸肌活动时活跃；在屈曲反射中，膝关节屈肌在髋屈肌活动时活跃。我们在这些运动模式中记录了单个下降本体脊髓中间神经元的活动。我们测试了Grillner的CPG组织单元爆发发生器假说的预测，其中每个自由度的每个方向都由特定模块控制，例如髋屈肌、髋伸肌、膝关节屈肌、膝关节伸肌等。我们研究了在每个自由度的激动剂和拮抗剂运动输出之间有节奏交替的正常吻侧划伤过程中，作为每个模块候选成员的中间神经元；拮抗剂活性发生在激动剂静止期间。我们测试预测神经元间的活动或安静在3运动模式变化的吻侧划痕，称为删除。在拮抗剂缺失期间，连续的激动剂爆发之间没有静止，也没有拮抗剂运动活性。我们研究与臀部和膝盖相关的缺失。我们测试了当口袋划痕与吻侧划痕比较时神经元间相恒定或移动的预测，以及在弯曲反射期间神经间激活或静止的预测。我们的实验揭示了海龟CPGs的关键特征。包括人类在内的所有脊椎动物的脊髓组织都有相当大的相似性。我们对CPG组织的发现将对那些开发脊髓损伤人类新疗法的人感兴趣。

DESCRIPTION (provided by applicant): Neuronal networks in the spinal cord, termed central pattern generators (CPGs), have considerable motor capacity and can be activated by cutaneous stimulation in a spinal vertebrate with complete spinal cord transection. CPGs produce coordinated motor output in model systems of spinal vertebrates immobilized with neuromuscular blockade. The immobilized spinal turtle produces the motor patterns of mixed-synergy rostral scratch, conventional-synergy pocket scratch, and conventional-synergy flexion reflex. In rostral scratch, monoarticular knee extensors are active during hip-flexor activity; in pocket scratch, monoarticuiar knee extensors are active during hip-extensor activity; in flexion reflex, knee flexors are active during hip-flexor activity. We record single-unit descending propriospinal interneuron activity during these moter patterns. We test predictions of Grillner's unit-burst-generator hypothesis of CPG organization in which each direction of each degree of freedom is controlled by a specific module, e.g., hip flexor, hip extensor, knee flexor, knee extensor, etc. We study interneurons that are candidate members of each module during normal rostral scratch with rhythmic alternation between agonist and antagonist motor output at each degree of freedom; antagonist activity occurs during agonist quiescence. We test predictions of interneuronal activity or quiescence during 3 motor-pattern variations of rostral scratch, termed deletions. During an antagonist deletion, there is no quiescence between successive agonist bursts and no antagonist motor activity. We study hip-related and knee-related deletions. We test predictions of interneuronal phase constancy or shifting when pocket scratch is compared with rostral scratch and predictions of interneuroral activation or quiescence during flexion reflex. Our experiments reveal critical characteristics of turtle CPGs. There is considerable similarity in the organization of spinal cord in all vertebrates, including humans. Our findings of CPG organization will be of interest to those developing new therapies for spinal-injured humans.