system
Given the following post, respond as if you're commenting on Reddit:
human
Why is it when you close your eyes in a dark room, you can still see colours moving or swirling around?
gpt
Your brain is always looking for patterns, so in the absence of any input at all, the complex pattern recognition systems of the visual cortex create "meaning" as they amplify the neural noise always present.

It's between V1 and V2 that there is the strongest feedback, so this means that the visual perception that is spontaneously evoked is mainly morphing "blobs", the only discernable factor being contrast, as is their function.

If you would injest a 5-HT2A agonist like psylocybin, you might see the even more complex interactions of the higher visual complexes, which manifest as alterations in spatial perception and very elaborate geometric patterns.