Neuroanatomical Tract-Tracing Methods

Times of dramatic progress in brain research have often been correlated with the development of new and powerful techniques that have changed the kinds of questions one can ask. An historical example may illustrate the point. More than 50 years ago, Nissl studies (Ferraro, 1928) showed that extensive forebrain lesions resulted in chromatolysis and cell loss in the sub- stantia nigra; thus, it was suggested that the substantia nigra gave rise to projections into the basal forebrain. In the late 1950s, another clue emerged, this time linking observations from the field of neuropathology with a dis- covery in experimental neuropharmacology (Carlsson, 1959a,b; Ehringer and Hornykiewicz, 1960). It had long been recognized that patients with Par- kinson's disease suffered neuronal loss in the substantia nigra and that their symptoms were somehow related to striatal dysfunction. Thus, when flu- orescent catecholamine assays were developed and combined with pharma- cological and neuropathological studies of Parkinson's disease, the dopamin- ergic nature of the illness was shown. A bit later, Falck and Hillarp (Falck et at. , 1962) developed a fluorescent histochemical method to visualize mono- amine-containing cells in the brain; this technique was soon applied to show that the rich dopaminergic terminal field in the striatum derived from neu- rons in the substantia nigra (Anden et at. , 1964). In the following decade, refinements in the histofluorescent method and the development of sensitive silver impregnation methods permitted a detailed light microscopic explo- ration of the dopaminergic nigrostriatal system.

Table of Contents:
1 Experimental Neuroanatomy: General Approaches and Laboratory Procedures.- I. Introduction.- II. Tract-Tracing Methods.- III. Practical Problems.- IV. Analysis.- V. The Neuroanatomical Laboratory.- VI. Appendix.- 2 Methods for Selective, Restricted Lesion Placement in the Central Nervous System.- I. Introduction.- II. Stereotaxic Technique.- III. Nonselective Lesion Techniques.- IV. Evaluation of the Electrolytic Lesion.- V. Selective Lesion Techniques.- VI. The Interpretation of Lesion Effects.- VII. Appendix: Stereotaxic Atlases.- 3 Methods for Delivering Tracers.- I. Introduction.- II. Pressure Injection.- III. Iontophoretic Injection.- IV. Appendix.- 4 Silver Methods for the Impregnation of Degenerating Axoplasm.- I. Introduction.- II. Theoretical Considerations.- III. Practical Aspects.- IV. General Characteristics of the Silver Methods.- V. Interpretation of Degenerating Fibers and Terminal Degeneration.- VI. Other Degenerative Neuronal Phenomena.- VII. Sources of Error.- VIII. Summary of Advantages and Limitations.- IX. Prospects for the Future.- X. Appendix.- 5 The Autoradiographic Tracing of Axonal Connections in the Central Nervous System.- I. Introduction.- II. The Principles of the Method.- III. Methodology.- IV. Analysis of the Data.- V. Electron Microscopic Autoradiography.- VI. Summary of Advantages and Limitations.- VII. Appendix.- 6 Horseradish Peroxidase: The Basic Procedure.- I. Introduction.- II. Basic Applications.- III. Incorporation and Transport of HRP.- IV. Methodology.- V. General Characteristics of the Different HRP Methods.- VI. Results and Interpretations.- VII. Summary of Advantages and Limitations.- VIII. Appendix.- 7 Horseradish Peroxidase: Intracellular Staining of Neurons.- I. Introduction.- II. Methods.- III. Application of the Technique.- IV. Summary of Advantages and Limitations.- V. Appendix.- 8 Horseradish Peroxidase and Fluorescent Substances and Their Combination with Other Techniques.- I. Introduction.- II. The Tracing of Collateral Projections.- III. HRP and Anterograde Tracing Methods.- IV. HRP and Transmitter-Related Histochemical Procedures.- V. HRP and 2-Deoxyglucose Procedures.- VI. Prospects for the Future.- VII. Appendix.- 9 The Golgi Methods.- I. Introduction.- II. The Rapid Golgi Method.- III. Analysis of the Data.- IV. Presentation of the Data.- V. Variations of the Golgi Method.- VI. Summary of Advantages and Limitations.- VII. Appendix.- 10 Electron Microscopy: Preparation of Neural Tissues for Electron Microscopy.- I. Introduction.- II Basic Procedures for Fixation and Embedding.- III. Variations.- IV. Evaluation of Results with the Light Microscope.- V. Cutting and Staining Ultrathin Sections.- VI. Synthesis.- VIII. Appendix.- 11 Electron Microscopy: Identification and Study of Normal and Degenerating Neural Elements by Electron Microscopy.- I. Introduction.- II. Bridging the Gap between Light and Electron Microscopy.- III. Practical Guidelines for Electron Microscopy.- IV. Identification of Neuronal Elements.- V. Ultrastructure of Degenerating Nerve Fibers.- VI. Morphometry.- 12 Tract Tracing by Electron Microscopy of Golgi Preparations.- I. Introduction.- II. General Description of Techniques.- III. Summary of Advantages and Limitations.- IV. Concluding Comments and Troubleshooting.- V. Appendix.- 13 Fluorescence Histochemical Methods: Neurotransmitter Histochemistry.- I. Introduction.- II Chemical Basis of the Fluorescence Histochemical Methods.- III. Equipment.- IV. Methods Using Formaldehyde or Glyoxylic Acid Condensation.- V. The Selection of Fluorescence Histochemical Methods.- VI. Advantages and Limitations of the Fluorescence Histochemical Method.- VII. Appendix.- 14 Immunocytochemical Methods.- I. Introduction.- II. Types of Immunocytochemical Techniques.- III. The Peroxidase-Antiperoxidase (PAP) Technique.- IV. Variations in PAP Technique.- V. Specificity of the PAP Technique.- VI. Use of the PAP Technique in the Demonstration of Catecholaminergic Neurons.- VII. Use of the PAP Technique in the Localization of Neuropeptides.- VIII Summary of Advantages and Limitations of the PAP Technique.- IX. Conclusions.- 15 The 2-Deoxyglucose Method.- I. Introduction.- II. Basic Principles of the Method.- III. General Applications of the Method.- IV. Methodology for [14C]-2DG.- V. Methodology for [3H]-2DG.- VI. Data Analysis.- VII. Advantages and Limitations.- VIII Appendix.- Epilogue: Some General Advice to the Young Investigator.- Author Index.