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In 1898, Camillo Golgi, an eminent Italian physician and pathologist, published a landmark paper on the structure of “nervous cells.” In addition to the organelle that still bears his name, the Golgi apparatus, he described “a delicate covering” surrounding neurons’ cell bodies and extending along their dendrites. That same year, another Italian researcher, Arturo Donaggio, observed that these coverings, now known as perineuronal nets (PNNs), had openings in them, through which, he correctly surmised, axon terminals from neighboring neurons make synapses.
Since then, however, PNNs have been largely neglected by the scientific community—especially after Santiago Ramón y Cajal, a fierce rival of Golgi (who would later share the Nobel Prize with him), dismissed them as a histological artifact. It wasn’t until the 1970s, thanks to ...
