Two forms of time perception.
But my point was memory is impaired in all forms except the one only measuring tracking estimates. Because you won't have any higher brain function with a cortex removed so they can't evaluate autobiographical memory because it won't exist.
And making short time estimates is done by the brain stem.
Even with no cortex. Likely because circadian rhythm is somewhat controlled from cerebellum.
No cortex makes one essentially brain dead in many ways. No language. No sensory processing. No vision hearing or touch perception. No internal thoughts. Nothing. (Look up "default mode network, and why internal thoughts won't exist without a cortex).
Brain stem mostly regulates things like heart beat and breathing. Cerebellum has its own unique function but does not process higher order cognition.