system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What happens to the brain after a tumor is removed? Does the brain regenerate the lost space/damaged functions?
gpt
No there is an empty hole where the brain matter was. Sometimes new paths can be formed but alot of times function and ability can be lost. 

Source: ex wife had a brain tumor that was removed and had to go for countless followup mris.