LLMs are nothing like the way the brain works. Since I don't think prolepsis isn't necessarily how the brain actually functions, I'm sharing a couple videos explaining the brain as prediction machine. The mind doesn't break reality into tokens and assign values to then assign probabilities. The brain works with past experience and sensory input.
For y'all's consideration...
That said, I don't even think LLMs are analogous to ancient Epicurean prolepseis. As I understand, the prolepseis engrave channels in our psykhē to make it easier for similar eidola to find their channel, making our psykhē recognize the pattern and assign meaning.
The LLM video (Thanks. Kalosyni!) did a good job of breaking down the process. I don't see ancient Epicurean prolepseis nor modern brain as prediction machine working like that at all.