some years ago in the department of anatomy in the little sleepy German town of Tübingen, i learnt about the history of tagging brain cells and looking at them under the microscope… it was pretty amazing to think that what one could see can lead to powerful inference about how the network of cells within the whole brain might be communicating. two pioneers, Golgi and Cajal both had differing ideas of how that communication might exist, based on what they saw. Golgi saw cells or neurons in a cloud-like mesh and thought of them as a composite entity while Cajal found each neuron to be a single entity and postulated that communication between them might occur in the space between them; the junction we now call a synapse. their differences were not resolved even when both were jointly awarded the 1906 Nobel Prize recognizing both their achievements.

since then, we have come to appreciate Cajal’s foresighted inference with better viewing tools. and many other scientists have sought to tag cells and other sub-cellular structures to better understand their form and function. this year’s Nobel prize in Chemistry is shared by three of them who used a green glowing fluorescent protein (GFP) found in a deep ocean octopus! it sounded crazy to me when i first learnt about that in class. but when i saw how fluorescent proteins worked when tagging the peripheral nerve cells i have stained in one of my lab rotations, i felt just as Cajal probably did when he first saw the Golgi stained cells. dumbfounded. the microtubulins and actin filaments and dying cells glowed green, red and blue, respectively, under the microscope. i marveled at how minuscule those red-stained filaments looked and how so vital they are in the many wondrous things every cell in each of us does.

here’s a picture of modern day tagging at its artistic best… brain cells of a lab mouse glowing in multicolour protein tagging

(picture courtesy of NYTIMES © AP Photo/Harvard University, Livett- Weissman-Sanes-Lichtman)

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