Ibn al-Haytham (circa 1027, published in 1083). From Book of Optics. Courtesy of the Süleymaniye Library, IstanbulA human brain is remarkably heavy when you hold it in your hands. I had the chance to do just that when I attended my friend Wendy Suzuki’s first neurobiology class of the semester at NYU last month.
Wendy told her students that she became a scientist because of an experience in a class just like this one, which she took during her freshman year at UC Berkeley. She was hooked when her teacher, the renowned neuroscientist Marion C. Diamond, opened up a hatbox and pulled out a human brain, saying “This is the most complex structure known to us – it’s the only structure that can think about itself.”
Wendy had invited me to her class because she talked about a chapter in Spark during her lecture, using the painter Chuck Close’s experiences with severe learning disabilities to explore why neurobiology is central to our lives. She also spoke about Portraits of the Mind, by Carl Schoonover, which has extraordinary images of how we’ve tried to imagine and capture what happens in the brain. The oldest known image in the book is almost a thousand years old, a startlingly accurate drawing of the optical system by Ibn al-Haytham of Cairo.
Wendy also projected this drawing of a dog's olfactory bulb by Camillo Golgi, from 1875. 
Camillo Golgi (1875). Courtesy of Dr. Paolo Mazzarello, University of Pavia
Golgi's draftsmanship is so beautiful that his drawing could hang in a gallery as a work of art, but he was a groundbreaking scientist who invented a way of staining tissue so it can be studied. The Golgi Stain is still in use today.
Thomas Deerinck and Mark Ellisman (2004)Portraits of the Mind offers athought-provoking journey through how we've tried to make sense of the brain, from Ibn al-Haytham's schematic drawing to contemporary technicolor images of the hippocampus. These pictures were much more vivid than the preserved human brain Wendy placed into my hands, a wrinkled, tannish double handful. She described how the elaborate folds in the brain allow it to have maximum surface area in a minimum amount of space, so that babies' heads can fit through the birth canal. The mass of wrinkled matter wasn’t visually inspiring, but I found myself in awe, holding in my hands a mind that had once thought, moved, lived.