You can't will yourself to see the world in shades of gray!

"The patient can quite deliberately and very selectively turn the volume on her medial temporal lobe neurons up and down. But many regions of the brain will be immune from this influence. For instance, you can't will yourself to see the world in shades of gray. This most likely means that you can't consciously downregulate color neurons in your visual cortex. And much as you may sometimes want to, you can't turn off the pain centers in your brain."