Collective Unconscious Help

[casket case]

Okay, I don't understand this at all, and no amount of googling or walkthroughs has ANY mention of it.

When you're in the Collective Unconscious, there are 4 'picture frames' surrounding each door. One is for emotional baggage, one is for vaults, one is for mental cobwebs, and the last one looks like a bunny. I've already played through the game, I know the significance of the bunny, but that doesn't really apply until much later. I know that if the 'picture frame' is lit up, that means you've completed or collected whatever the thing is (sorted all baggage, collected all cobwebs, etc)

But I can't figure out for the life of me what the bunny is supposed to represent or how to get that frame to light up. Currently, I have access to the Experiment, Basic Braining, Sasha's mind, and Milla's mind. I've completed the experiment and cleared Sasha's and Milla's minds, but the bunny only shows up for Sasha and Milla, not for the brain tumbler experiment. I'm going to clear Basic Braining and see what happens, but does anyone know what the bunny is or what it means? How do I get that frame to light up?

[anonymous_cat]

The last frame is for figments, so it'll light up if you gathered all the figments in a world. If it hasn't lit up for the Experiment, that means that you must've missed some figments somewhere.