The prepped Gina brain is a quest item in Fallout 76, introduced in the Wastelanders update.
Gameplay
It is the brain of Gina Bailey, preserved in a jar and chemically prepared for installation into a robobrain.
Locations
It can be obtained by successfully preparing Gina's brain at the RobCo Research Center during the quest Duty Calls. Doing so will remove Doctor Dias's brain and Greg's brain if they are present in the player character's inventory.