So I thought up this alien parasite that enters through the mouth (usually of a predator) where it attaches to the throat and simultaneously takes control of the brain and replaces the esophagus of the victim. It basically sends the unfortunate host into a feeding frenzy, eating as much as possible, with the alien worm-like parasite taking in all the food. Obviously the host will eventually die from starvation and the parasite then lays her eggs in the carcass, her many offspring feeding off of both the carcass and the meat stored in the mother from the feeding frenzy.
The two problems I face are obviously the infection of the parasite and the structure used to control the brain. This question focuses on the latter.
The parasite doesn't control everything, it only forces the creature into a frenzy. If the creature was sentient, it would be too overcome by said frenzy to be able to speak, however most other cognitive functions, reflexes and instinct as well as use of tools are active. The host is not a fumbling zombie, if the parasite infected a tiger it would be just as lethal, maybe even more so, than an uninfected tiger. The host is basically still in control, but under an extreme influence, their mind is given a single drive and they do everything it takes to follow it.
The question I'm asking is, what kind of structure or process would facilitate this kind of 'control' over the host?
Please, if you don't understand my question tell me what I'm missing so that I can edit it to suit.