Pío del Río Hortega

Pío del Río Hortega (1882 – 1945) was a Spanish neuroscientist who first distinguished microglia from the other brain cell types. Río Hortega was the first to distinguish microglia, which are the immune cells of the brain, from astrocytes and oligdodendrocytes. He also introduced the term microglia.

He identified microglia as separate from other glial cells by staining tissue with ammonium silver carbonate. He published the work on oligodendroglia in 1921, which both he and Penfield are now credited with.

As with many early neuroanatomical findings, his discoveries were subject to controversy, including a scientific and personal conflict with Ramón y Cajal. The bombing of Britain by Germany in World War II drove him on to Argentina in August 1940. His move was funded by the Spanish Cultural Institute, who continued to support him as he created his own laboratory in 1942. In Buenos Aires he developed a fruitful scientific school with former disciples who worked with him in Europe (Moisés Polak, Washington Buño ) and new ones, including chronologically the last one, Amanda Pellegrino de Iraldi. Río Hortega died in Buenos Aires on 1 June 1945 from a malignant neoplasm.