Science Daily explains the new research like this (which was a little bit easier for me to understand):
"Researchers have pinpointed a mechanism in the brains of mice that could explain why some human mothers become depressed following childbirth.
The discovery could lead to improved treatment for postpartum depression. After giving birth, female mice bred to be deficient in a suspect protein showed depression-like behaviors and neglected their newborn pups.
Giving a drug that restored the protein's function improved maternal behavior and reduced pup mortality.
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