David Hubel was a distinguished Canadian scientist. He is well-known for his studies on the primary visual cortex which helped pave the way for the field of systems neuroscience. 

Santiago Ramon y Cajal is arguably one of the founding fathers of neuroscience. His birthday is May 1st, 1852 and would have been 165 this year. He was awarded the Nobel Prize in Physiology or Medicine for his early discoveries on the structure of the brain. Fun fact about Cajal – he remains extremely well known in the Spanish community, so much so that his life has become a TV miniseries.