Projecting film onto the ceiling of an indoor tent is a fun summer evening activity. It was also a laboratory setup at Johns Hopkins in the 1960s. What’s more exciting is that this setup led to a body of work that netted the tent-pitchers a Nobel Prize. Their finding in the tent is taught in all introductory neurobiology textbooks - the existence of cells sensitive only to particularly oriented lines. And it was all an accidental discovery that took place under these covers. 

These experiments began with a cafeteria meeting in 1959, where David H. Hubel met Stephen Kuffler and Torsten Wiesel. After confirming their interests in studying visual information processing in a superficial layer of the brain (the cortex), Hubel and Weisel set up their tents in Kuffler’s laboratory. 

Their experiments involved cats looking at the ceiling of this small indoor “circus arena,” where dark or light dots were projected while monitoring the activity of a single neuron. Their goal was simple: to understand what visual pattern activated these neurons. They used dots, drawn on glass slides to make the projection equipment work, since they knew they reliably stimulated retinal cells in the cats' eyes. After weeks of experiments, with various mishaps including accidentally spraying themselves with formalin (similar to formaldehyde), they triggered an avalanche of neuronal activity. 

Next to the projected dots was a shadow line cast from the edge of the glass slide the dots were drawn on. This line, an accidental stimulus rising from imprecise slide placement, revealed the existence of orientation sensitive cells, or cells that respond only to lines in certain angles, also sometimes called “simple cells.” Soon, they also found “complex cells,” neurons that responded to lines moving in a particular direction or having directional selectivity. (Their use of “simple” and “complex” highlight the increase in information processing as information passes through the brain, as simple cells are thought to send information to complex cells.) 

Hubel and Wisel paved the path for studying how the brain processes information. Their names and their work are revered in neurobiology, but their laboratory adventures and beneficial mishaps are less often remembered.