I'm almost positive that the brainstem is responsible for all those other senses. It's the oldest and simplest part of our brains. I believe it's often referred to as the reptilian portion of brain because it was the first part of the brain to actually evolve and has been around since the time the dinosaurs arose. All those senses are hard wired into that, and that's why every animal has them. Isn't the cerebral cortex the outer most wrinkly looking stuff on our brains? I thought that was for the majority of the brain processing required to give humans things like speech, cognitive thought, and incredible memory? A lot of lower species lack that entirely and still have the five main senses which are arguably stronger and more effective in them than they are in humans.
I could be completely wrong, but a few years ago I became really interested in the brain and read a lot about it. Maybe my memory just sucks.
The mesencephalon (upper part of the brain stem) is associated with hearing and vision, but every sense still has its own sub-cortex. However, given that the brain stem primarily deals with the nervous system, it's possible that the senses would still register, but without a cortex to process it, there would no recognition of that sensation or ability to assign cognitive thought to it. Combined with the instinctual urges governed by the brain stem, a zombie would simply regard any smell, sight, etc. as food (or not food.)
Of course, the zombies should also have a heartbeat, the ability to feel pain, and a regular sleep cycle, since the brain stem controls all of that stuff as well. I suppose the best explanation for this is the very fact that we've been conveniently overlooking the entire time - the brain stem is processing nerve signals from necrotic tissue, so the virus would need to reactivate the entire central nervous system for any of this to fly, and since dead tissue has no need for nutrients, sleep, and is unaffected by pain, those aspects of the CNS simply atrophy along with the flesh.
As for the evolutionary stuff, I would argue that the brain stem's functions are even more elementary than the senses. Before the dinosaurs there were bacteria, and all life has instinctual urges; organisms evolved senses as a way to better meet those instinctual needs for survival, so I would say that the order of sophistication in brain function (and consequently, size of the cerebral cortex) goes in the following order: Instincts --> Sensory Perception --> Cognitive Reasoning
Note: I only have a very basic knowledge of cerebral anatomy and have just been speculating this entire time.
Topic: The Walking Dead, Season 3 (Read 59854 times)
