10. Drawing of perineuronal astrocytes in cerebral cortex from Ramon y Cajal. This drawing is from Cajal's late work focused on glia. Astrocytes are the most abundant cells in the human brain and play very important roles in brain function, such as removing the excess glutamate near the synapse, regulation of extracellular ion homeostasis and controlling of synaptogenesis and synaptic maintenance. Beside science, this is really like an Asian ink wash painting.
(Image Credit: Constantino Sotelo/Nature Reviews Neuroscience)

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Sotelo, Constantino. "Viewing the brain through the master hand of Ramon y Cajal." Nature Reviews Neuroscience 4, no. 1 (2003): 71-77.