Functional Organization of Motoneuron Pool and its Inputs

摘要: The sections in this article are: 1 Morphological Considerations 1.1 Columnar Arrangement of Motoneuron Pool 1.2 Dimensions α-Motoneurons and Distribution Cell Size 1.3 Scaling Motoneurons 1.4 Initial Segment α-Motor Axons 1.5 Axon Collaterals α-Motoneurons 1.6 Recurrent Inhibitory Feedback from Motoneurons 1.7 Direct Synaptic Interconnections Between Spinal Motoneurons 1.8 Species Motoneurons 1.9 Terminals Motoneurons Muscle 1.10 Morphology Neuromuscular Junctions 1.11 Matching the Properties Muscle Fibers They Supply 1.12 Concluding Comments 2 Firing Patterns Individual Motor Units 2.1 Functional Significance Size Motoneurons 2.2 Measurement Total Output Pools 2.3 Critical Firing Levels Motoneurons 2.4 Relation Critical Level to Axon Diameter Size 2.5 Effects Inputs on Rank Order During Repetitive Firing 2.6 Recruitment Units Humans 2.7 Evidence Regarding Alternative Recruitment 2.8 Evidence Voluntary Selective Control Units 2.9 Size Principle Other Species 2.10 Modulation Rate 3 Organization Input Pools 3.1 Anatomical Studies 3.2 Techniques Used Study EPSPs Elicited by Impulses Single Afferent Fibers 3.3 Amplitudes Fibers 3.4 Boutons Ia-Fibers Motoneurons 3.5 Physiology Ia-Terminals 3.6 Distribution Ia Excitation Pools 3.7 Comparison Projections Homonymous Heteronymous Motoneurons 3.8 Correlations Morphology Function 3.9 Latency EPSPs 3.10 Other Examples Divergence Motoneurons 3.11 Ia-Projections Controlling Parts Body 3.12 Group II From Secondary Endings Spindles 3.13 Inhibitory Motoneurons 3.14 Group Ib Golgi Tendon Organs 3.15 Monosynaptic Descending Pathways 3.16 Topographic Factors Governing Development Connections Motoneurons 3.17 Concluding Comments 4 Nonuniformity Motoneurons 4.1 Early Classification Tonic Phasic Types Motoneurons 4.2 Significance Nonuniformity Fibers 4.3 Motoneuron Independent Size 4.4 Differential Responses Injected Currents 4.5 Influence Developing Mature Motoneurons 4.6 Evidence Human Disease 4.7 Concluding Comments 5 How Determines their Susceptibility Discharge 5.1 Properties That Influence Discharge 5.2 Role Determining Discharge 6 Some Principles Underlying Organization Pools 6.1 How Sensitivity Gradation Tension is Achieved 6.2 Basis for Relation Force Its Unit Develops 6.3 Actual Grading Muscular Tension 6.4 Mathematical Derivation a “Principle Maximum Sensitivity” 6.5 Recruitment Minimum Energy Principle 6.6 Collective Action Pool: Role Input 6.7 The Group Sensory Fibers 6.8 How Does Central Nervous System Use Pool?