One of the greats of neuroscience
David H. Hubel moved to Montreal at the age of three where he was raised and eventually graduated from McGill University with degrees in mathematics, physics, and medicine. Dr. Hubel taught and conducted research at Harvard University Medical School where he co-authored a series of ground-breaking papers on his studies of the visual cortex.
His experiments with Dr. Torsten Wiesel showed how certain cells "read" information, which is subsequently processed with greater complexity by other cells. The messages are then sent to the higher centres of the brain where a visual impression is created, and the memory of the image is stored. This research established the concept of "critical periods" and showed that if an animal failed to receive adequate visual experiences, the result was a decline in the performance of the visual system.