The typical pain signal follows a well-worn path from the brain stem through the midbrain and into the cortex, where conscious feelings of pain arise.
When you are stuck in traffic or overwhelmed at work or worn down by the kids, the hypothalamus--a structure buried deep in the midbrain--tells your adrenal gland to pump out a .
As all those complex processes were unfolding, your midbrain filed away a simple, primal, unconscious idea: Cupcakes are good.