system
Given the following post, respond as if you're commenting on Reddit:
human
Does the brain undergo physiological changes while depressed? If so what kind of changes specifically?
gpt
Depression can shrink various parts of the brain, specifically the hippocampus (responsible for emotional management, learning, and memory) and prefrontal cortex (complex thought and planning). There's speculation that the amygdala (the fear center and further emotional management, largely "negative" emotion) is altered physically as well, though it's not known whether or not depression shrinks or increases that area's mass over time.

There are other areas of the brain that are debatably affected by long-term depression, but a lot of that is speculation and hasn't been studied enough.