I take brain science / cognitive studies with a grain of salt. (To his credit, he does mention peptides, the heart, and other systems, with a sweep of his hand.) That said, Dr Danny Siegel's work is at the forefront of my attention, and this may be his most accessible for a mass audience. His illustration of the brain as your palm is worth a look, in and of itself. He finds the prefrontal cortex as regulating nine functions, and interesting what they are and how they interconnect; for instance positive "attachment" (as in Attachment Theory) and mindfulness.