It's similar to the brain possessed by the hardy reptiles that preceded mammals, roughly 200 million years ago. It's 'preverbal', but controls life functions such as autonomic brain, breathing, heart rate and the fight or flight mechanism. Lacking language, its impulses are instinctual and ritualistic. It's concerned with fundamental needs such as survival, physical maintenance, hoarding, dominance, preening and mating. It is also found in lower life forms such as lizards, crocodiles and birds. It is at the base of your skull emerging from your spinal column.
VM how thoughtful to post pictures of your cranial x-rays, so exciting, especially the diatribe you attached explaining your x-ray. I am deeply touched...
"We Are All Travellers, From The Sweet Grass To The Packing House, From Birth To Death, We Wander Between The Two Eternities". An Old Cowboy.