i dont think after some neuro toxins the victim can be awake...i posted above some usefull information that will "probably" explain this.The human body can survive withought the brain but the brain cannot do so and the body dosent need the brain to function..the sol purpose of the brain is to comand the body so if it dies you are turned into a patato (tho spinal reflexes function withought the brains oversight and those can remain intact)
EDIT: As to my knowledge the deffinition of a zombie is nothing more that a mindless monster (human in our case) and the fact that it "eats brains" strongly sustain this...it simply dosent have the capability to think
