Reality flows in. Imagination flows out.
According to the latest scientific research, reality and imagination flow in opposite directions in the brain. Reality starts with low-level processing then moves to high-level cognition, while fantasy starts deep in the brain and flows out to low-level processing areas. It's an enormously satisfying visual representation of how I always thought imagination worked.
When writing, every scene starts with a spare idea. A bar fight, for example. This grain of thought accretes layers of detail as I work on it. Who is fighting, where, why. Then what they look like, the smell of the bar, the motion of a swinging fist, the sound of bone on flesh. All the tiny sensory elements that make a scene vivid come last. The flow from the high tower of ideas to the earthy reality of a fist to the face.
This past year, I had the worst case of writer's block I've ever had. I was going through a bad time personally and was very shut-down and depressed. Cored by grief. And my writing showed it. I couldn't get from idea to detail. It was like the flow stopped before it reached the sensory stage. I couldn't get to that place where I picture the scene as if I'm living it in my brain and transcribing an eyewitness account. My writing was all ideas, no substance. I recognized the problem, but couldn't fix it. Which made the block even more painful.
As I healed, the writer's block eased up. I started seeing the drama again, not just knowing intellectually how it should play out. I could write with my senses again. And now science confirms what I felt all along about how writing moves through my mind.
Writer's block is a terrible thing to suffer through. Losing your means to cope with pain and stress when you're at your most pained and stressed is a cruel joke. I hope this study means that someday it will be curable.