What Is Consciousness and Where Does It Come From?

When i began, when i was interested in neurology and nervo surgery as a medical student, annd subsequently in my career, i initially thought that i would gain a very deep insight into into the soul by studying the brain. And i've come to realize that there's much about us that doesn't show up in the brain. But one of the things that i challenge my students on is where does consciousness actually come from? I think saint thomas has had the explanation that best fits what i've seen in 35 years.