Tools of the brain trade, past & present

Jennifer Ouellette reports from a month-long program on the anatomy, development and evolution of the brain, at the Kavli Institute for Theoretical Physics, with a fantastic post called Tools of the brain trade.

Inspired by a talk given by Winifred Denk, about reconstructing brain circuitry using serial electron microscopy, Jennifer's post covers the discovery by Camillo Golgi of the silver chromate method for impregnating samples of brain tissue, and the refinement of the technique by Santiago Ramon y Cajal. It concludes with a brief mention of modern imaging techniques, such as two-photon microscopy.

As I discussed in Discovery of the neuron, Golgi and Cajal differed in their views of the fine structure of the nervous system. Whereas Golgi believed it to consist of a continuous network of tissue, Cajal argued that the brain is instead composed of discrete functional elements.

This argument continued for the best part of the nineteenth century. Eventually, the latter view prevailed, and we now know those discrete elements as neurons. This was largely down to Cajal, who, ironically, used Golgi's staining method to elucidate individual nerve cells. (The image above shows Cajal's diagram of the hippocampus, stained using the Golgi method.)

Jennifer says that it's "Brainiac week" at her Cocktail Party Physics blog, so I'm already looking forward to more coverage of the KITP program from her. The organizers of the program have uploaded podcasts and QuickTime movies of the talks given so far. There's a lot of interesting stuff there, and I'll definitely be taking a closer look when I have more time on my hands.