It is said that the soul is the seat of emotions, intellect, and will, but the brain is involved in each of these functions. What is the difference between the brain and the soul?
First it will be helpful to look at where both soul and brain stand in relation to personhood. It is a mistake to confuse the soul and the person; nor is the soul merely that which is "personal" in us. But the soul is such a fundamental dimension of the person that in Scripture, poetry, and in common life, soul often means the person. Soul in the Bible sometimes—perhaps most of the time—refers to the whole person, precisely because it represents a deep dimension of the person.
The relation of the brain to personhood, too, is frequently misstated. Because scientists tend to take the brain as central to life, people often construe it as identical with life. This is because the scientific community generally assumes, in practice if not in theory, that only that which is physical is knowable. Scientists often believe they can treat the personal side of life only if it is physical.
Clearly there is in human beings a profoundly important connection between the states and events of the brain and those of personal existence. But the person is not identical with the brain (or the DNA or the body as a whole). Why? Because there are thousands upon thousands of truths about the person that are not truths about the body. And there are many kinds of truths about persons that are not the kinds of truths that apply to the body or any part thereof. Inspect the brain in any way you will; you will not find these truths or even know that they exist from what you do find there. Gottfried Wilhelm Leibniz (1646-1716) pointed this out long ago, and no satisfactory way around ...