One hundred years of Golgi's "perineuronal net": history of a denied structure

Perineuronal nets are reticular structures enwrapping cell bodies and the l argest dendrites of several neuronal populations. Discovered by Camillo Gol gi, who described them in detail in 1898, they were intensely studied by th e most famous contemporary neurohistologists for about twenty years. The op inion of Ramon y Cajal that perineuronal nets were a fixation artifact ende d the first period of studies. Only a few researchers, among whom the Itali an neurologists Besta and Belloni, went on with their studies up to the 193 0s documenting the morphology of perineuronal nets of different mammals and of man both in normal and in pathological conditions. Only after about fif ty years, the advances in the field of cytochemistry allowed the elucidatio n of not only the actual existence of perineuronal nets, but also their che mical nature, showing conclusively that they are complex organisations of e xtracellular matrix molecules, namely glycoproteins and proteoglycans. The research on perineuronal nets today involves several groups engaged to eluc idate their biological properties and functional role.