Current Topics in Neurobiology

1. Cell Lineage in the Development of the Leech Nervous System.- 1. Introduction.- 1.1. Developmental Cell Lineages.- 1.2. The Leech Nervous System.- 2. Leech Embryogenesis.- 2.1. Two Experimentally Favorable Leech Species.- 2.2. A Developmental Staging System.- 3. A Novel Cell Lineage Tracing Method.- 3.1. Horseradish Peroxidase Tracer.- 3.2. Fluorescent Tracer.- 4. Development of Germinal Bands.- 4.1. Ectodermal Stem Cell Bandlets.- 4.2. Mesodermal Stem Cell Bandlets.- 5. Origin of the Segmental Ganglia.- 5.1. Ectoteloblast Contribution.- 5.2. Distribution Pattern of Four Neuronal Kinship Groups.- 5.3. Number of Ganglion Founder Cells.- 5.4. Mesoteloblast Contribution.- 5.5. Origin of the Supraesophageal Ganglion.- 6. Cell-Specific Ablation.- 6.1. Role of Mesoderm in Ectodermal Development.- 6.2. Role of Ectoderm in Mesodermal Development.- 6.3. Morphogenetic Interactions within the Ectoderm.- 7. Conclusion.- 7.1. Governance of Cell Fate by Cell Lineage.- 7.2. Neuronal Kinship Groups.- 7.3. Segmentation.- 8. References.- 2. Origins of the Nervous System in Amphibians.- 1. Introduction.- 2. The Theory of Compartmentation.- 3. Predictions Made from the Theory and Their Experimental Verification.- 3.1. Deployment of Labeled Clones after HRP Injection into Ancestral Cells at Various Stages.- 3.2. Origins of Compartment-Specific Properties.- 3.3. Relation of Compartment Founder Cell Groups to Differentiated Cell Types.- 4. Critique of the Theory of the Organizer.- 4.1. Preliminary Considerations.- 4.2. Early Experimental Tests.- 4.3. Recent Experimental Tests with HRP Label.- 5. Compartment vs. Organizer Theories.- 5.1. The Case for the Compartment Theory.- 5.2. Difficulties with the Organizer Theory.- 6. References.- 3. Monoclonal Antibodies to Embryonic Neurons: Cell-Specific Markers for Chick Ciliary Ganglion.- 1. Introduction.- 1.1. Formation of Complex Connections in the Nervous System.- 1.2. Antibodies as Cytochemical Markers of Neuronal Cells.- 1.3. The Ciliary Ganglion, a Model of Neuronal Development in Vertebrates.- 2. Materials and Methods.- 2.1. Dissociated Cell Cultures.- 2.2. Immunological Procedures.- 2.3. Reagents.- 3. Results.- 3.1. Initial Selection and Cloning of Antibody-Producing Hybrids.- 3.2. Monoclonal Antibodies Specific for CG Neurons.- 3.3. Staining of Cranial Neural Crest Cells in Vitro.- 3.4. Cytotoxicity of CG-1.- 3.5. Other Monoclonal Antibodies.- 3.6. Blocking Studies.- 4. Discussion.- 4.1. The Specificity of These Monoclonal Antibodies.- 4.2. Possible Identification of CG Neuron Precursors.- 4.3. Independence and Identity of the Antigenic Determinants.- 4.4. Potential Heterogeneity of CG Neurons.- 5. References.- 4. Genetic Manipulation of Sensory Pathways in Drosophila.- 1. Introduction.- 1.1. Levels of Analysis.- 1.2. Advantages of Different Organisms.- 1.3. What Understanding Can We Gain from Genetic Manipulation?.- 2. The Experimental Material.- 2.1. Mutants.- 2.2. Mosaics.- 3. A Theoretical Framework.- 3.1. Binary Decisions.- 3.2. The Bithorax Complex.- 3.3. The Antennapedia Complex.- 3.4. Compartments.- 3.5. Evaluation.- 3.6. Working Hypotheses and Questions for Neurobiologists.- 4. Compartments Boundaries and Peripheral Nerves.- 4.1. General Neuroanatomy of Drosophila.- 4.2. Neuroanatomy of the Wing.- 4.3. The Behavior of Axons at the A-P Compartment Border.- 4.4. Evidence That the Compartment Border Is Intact.- 4.5. The Next Hypothesis-Pupal Nerves Guide Adult Axons.- 4.6. Evaluation.- 5. Central Projections in Mutants of the Antennapedia Complex.- 5.1. Antennapedia.- 5.2. Proboscipedia.- 5.3. Interpretation.- 6. Central Projections in Mutants of the Bithorax Complex.- 6.1. Different Classes of Receptors Form Different Projections.- 6.2. The Projection of Single Axons Is Not Always Precisely Specified.- 6.3. Axons from the Normal Wings of Mutant Flies Branch More.- 6.4. Some Axons from Homeotic Wings Follow Normal Wing Tracts.- 6.5. Some Axons from Homeotic Wings Follow Haltere Tracts.- 6.6. Some Axons from Homeotic Wings Find an Adequate Home in the Metathorax.- 6.7. Is The CNS Directly Affected by BX-C Mutations?.- 7. Analysis.- 7.1. Transplantation by Mutation.- 7.2. Special Contributions of Genetic Studies.- 7.3. The Strengths and Limitations of Mosaic Studies.- 7.4. The Role of Compartments.- 7.5. Evaluation and Prognosis.- 8. References.- 5. Embryonic Development of Identified Neurons in the Grasshopper.- 1. Introduction.- 2. The Grasshopper Nervous System.- 3. Grasshopper Embryology.- 4. Neuronal Precursor Cells.- 5. Early Axonal Pathways.- 6. Cell Lineage of the Median Neuroblast.- 7. Cell Lineage of Midline Precursor 3.- 8. Properties of the Progeny of a Single Precursor.- 8.1. Biochemistry.- 8.2. Physiology.- 8.3. Morphology.- 9. Morphological Differentiation.- 9.1. DUM 5.- 9.2. The H Cell.- 10. Physiological Differentiation.- 10.1. Chemosensitivity.- 10.2. Electrical Excitability.- 10.3. Electrical and Dye Coupling.- 11. Biochemical Differentiation.- 12. Temporal Sequence of Development.- 13. Segment-Specific Cell Death.- 14. Segment-Specific Differentiation.- 15. Limb Bud Removal Experiments.- 16. Conclusions and Questions.- 17. References.- 6. Nerve Fiber Growth and Its Regulation by Extrinsic Factors.- 1. Introduction.- 2. Behavior of the Growing Nerve Fiber Tip.- 2.1. Protrusion and Regression.- 2.2. Contacts of the Nerve Fiber Tip.- 2.3. Cell-Substratum Adhesion and Neurite Growth.- 3. Structure of the Growing Nerve Fiber.- 3.1. The Neurite.- 3.2. The Nerve Fiber Tip.- 4. Mechanism of Nerve Fiber Growth.- 4.1. Expansion of the Neurite Membrane.- 4.2. Growth of the Cytoskeleton.- 4.3. Protrusion, Adhesion, and Actomyosin Action.- 4.4. Force Exertion in the Growth Cone Margin; How the Neurite Grows.- 5. Regulation of Nerve Fiber Growth by Environmental Factors.- 5.1. Regulation by Cell-Substratum Adhesion.- 5.2. Regulation by Spatial Variations in Adhesivity.- 6. Regulation of Nerve Fiber Growth by Chemotaxis.- 6.1. NGF as a Chemoattractant.- 6.2. Behavioral Responses of Growth Cones That Indicate a Chemotactic Response to NGF.- 6.3. Mechanisms of Chemotactic Response to NGF.- 6.4. NGF Receptors and Electrical Currents.- 7. Future Prospects.- 7.1. Regulation of Actin Structure and Function.- 7.2. Intrinsic Regulation of Neuronal Morphogenesis.- 7.3. Interactions of Neurites with Other Cells and in Vivo Surfaces.- 8. Conclusions.- 9. References.- 7. Pioneer Fibers: The Case for Guidance in the Embryonic Nervous System of the Cricket.- 1. Introduction.- 2. First Connections between Periphery and Center: How and When?.- 2.1. Sensory Embryogenesis in the House Cricket Acheta domesticus.- 2.2. Technical Approaches to the Ablation of Pioneer Cell Bodies.- 2.3. Results of Laser Ablation of Embryonic Cerci.- 3. The Events of Sensory Embryogenesis: A Hypothetical Program.- 4. A Matter of Scale.- 5. Periphery and Center.- 6. References.- 8. Mechanisms for the Formation of Synaptic Connections in the Isogenic Nervous System of Daphnia Magna.- 1. Introduction.- 2. The Adult Visual System.- 3. Development of the Visual System.- 3.1. General Aspects.- 3.2. The Compound Eye.- 3.3. Development of the Eye-Lamina Projections.- 3.4. Recruitment of the Laminar Cells into Cartridges.- 3.5. Birthdates of Laminar Neurons.- 4. Experimental Perturbations of Development.- 4.1. Deletion of Photoreceptors.- 4.2. Delay of Photoreceptor Differentiation.- 5. Mechanisms for the Formation of the Eye-Lamina Projection.- 5.1. The Topographic Ordering of the Eye-Lamina Projection.- 5.2. The Equivalence of Target Cells.- 5.3. The Nature of the Interaction between Optic Axons and Laminar Cells.- 6. References.- 9. Cell Death in Neuronal Development: Regulation by Trophic Factors.- 1. Introduction.- 2. Neuronal Cell Death.- 3. Nerve Growth Factor.- 4. Parasympathetic Neurons.- 4.1. Neurite Extension.- 4.2. Neuronal Survival.- 4.3. Regulation of Long-Term Development.- 5. Other Ganglionic Neurons.- 6. CNS Neurons.- 6.1. Spinal Cord Neurons.- 6.2. Identified Populations.- 7. Conclusions.- 8. References.- 10. Neuromuscular Synapse Elimination: Structural, Functional, and Mechanistic Aspects.- 1. Introduction.- 2. General Features of Polyneuronal Innervation and Synapse Elimination.- 2.1. Dual Basis of Multicomponent End-Plate Potentials.- 2.2. Time Course of Synapse Elimination.- 2.3. Numbers of Motor Neurons, Muscle Fibers, and Synapses.- 2.4. A "Critical Period" for Neuromuscular Synapse Elimination?.- 3. Mechanisms Underlying Synapse Elimination.- 3.1. Morphological Changes.- 3.2. Dynamic State of Synapses.- 3.3. Cellular Interactions Related to Synapse Elimination.- 3.4. Competitive Synapse Elimination and the Rules Governing It.- 4. Models and Possible Molecular Mechanisms.- 4.1. Positive vs. Negative Feedback.- 4.2. A Model for Synapse Formation, Polyneuronal Innervation, and Synapse Elimination.- 5. Overview and Conclusion.- 5.1. Synapse Elimination Elsewhere in the Nervous System.- 5.2. Concluding Remarks.- 6. References.- 11. Regeneration and Regulation in the Developing Central Nervous System with Special Reference to the Reconstitution of the Optic Tectum of the Chick Following Removal of the Mesencephalic Alar Plate.- 1. Introduction.- 2. Review of Previous Studies of Regeneration in the Developing Central Nervous System.- 3. Recent Observations on the Regeneration of the Chick Optic Tectum.- 3.1. The Normal Morphology of the Chick Optic Tectum.- 3.2. The Normal Development of the Chick Optic Tectum.- 3.3. A Reexamination of Tectal Regeneration in the Chick.- 3.4. Experiments on the Organization and Plasticity of the Retinal Projection upon the Regenerated Optic Tectum.- 4. References.