Damasio is the head of the Department of Neurology at the University of Iowa College of Medicine.
He's made something of a reputation in philosophical circles for his writings on mind/body issues, starting with Descartes' Error (1994).
The title of that 1994 book suggests the thesis: that any separation of mind from body (and concomitantly, any separation of intellectual judgment from emotional reaction) is erroneous. Damasio hypothesized that rationality requires emotional input.
In part this was a development of the James-Lange theory of the emotions. That theory, you will recall, is this: our body instinctively reacts to a situation (by blushing, for example). The emotion we feel (embarrassment) is not the reason for the blushing. A sensory stimulus of some sort is the reason for the blushing. The emotion is a consequence of the bodily reaction.
Damasio said that James was "well ahead of both his time and ours" in this respect, and that he had "seized upon the mechanism essential to the understanding of emotion and feeling."
Damasio saw emotions as James did, while also inserting them into a broader picture of a feedback loop. If I feel embarrassed as a consequence of a blush, and I blushed because I opened a door when I shouldn't have, then I've learned to keep that door closed in analogous situations in the future. That is a perhaps overly simple example (and I am to blame for that example, neither James nor Damasio highlighted blushing -- I should feel embarrassed to learn it misrepresents either of them). But it is an example of something important to Damasio, something he called the "cognitive guidance role" of emotions, and thus of instinctive bodily responses.
I'll say something more about Damasio tomorrow, when I'll move on to another of his books, The Feeling of What Happens (1999).