I've recently seen this great video: How your brain tells you where you are. The video discusses how certain cells within the brain fire based on proximity to objects. There are great examples of experiments with brain cells and location.
I'm wondering if there's similar insight about how the brain processes light. I'm particularly interested in how light is processed in dreams, when no light stimulus is coming from the eyes.
It is possible to have dreams that are dark or light, but changing the level of ambient light is generally difficult in dreams. In fact, a common test for dreaming involves flipping a light switch. If the effect is unexpected, the person may be dreaming.
How do our brains actually process light?