The Evolution of Immunocytochemistry in the Dissection of Neural Complexity

After more than 70 years from its initial development, immunocytochemistry ( ICC ) has become a fundamental technique in the study of the nervous system . After a brief excursus along the history of the different techniques that led to substantial amelioration of the original indirect immunofl uorescence protocol, we discuss here the main advantages and disadvantages of the individual techniques for the study of central and peripheral neurons, in parallel with standardization , quantifi cation , and reaction bias . Particular attention is given to immunofl uorescence and its novel developments that allow high- resolution imaging at the light microscope level. The possibility of combining ICC with other fundamental techniques for analysis of neuronal circuitry such as neurotracing , electrophysiology , and molecular biology is also discussed, as well as a series of approaches for correlative light and electron microscopic studies. The emerging picture is that ICC still represents an invaluable tool for histological and cytological analysis of neural complexity.