Prayer is ultimately about relationship. It's so much more than asking things of God, or even saying things to God. It's a participation in the relationship shared by the Trinity and the relationship shared between the Trinity and humanity. It is, in two words, about becoming whole. Neuroscience offers us some marvelous insights into the power of relationships to make us whole (they can also wreck us). And interpersonal neurobiology, a branch of contemporary psychology, teaches us about the power of safe, secure attachments to literally remake the brain.
Here's a recommended book exploring all this. I've been researching this area for the past year and exploring the implications for spirituality. I've just started this book, but a perusal suggests it's just the right book to bring the primary sources (Allan Schore, Dan Siegal, and so many others...see the Norton Series for source materials) into conversation with Christian spirituality.
Dr. Thompson's book is short, well-written, and deeply immersed in the wellspring of Christian spirituality.
See also Thompson's useful website for more.