The second system, based on several other neuromodulators, is the biochemical source of the pleasant feeling tones that come from the actual—and anticipated—carrots in life.*When these “pleasure chemicals”—natural opioids (including endorphins), oxytocin, and norepinephrine—surge into your synapses, they strengthen the neural circuits that are active, making them more likely to fire together in the future.Imagine a toddler trying to eat a spoonful of pudding. After many misses, his perceptual-motor neurons finally get it right, leading to waves of pleasure chemicals which help cement the synaptic connections that created the specific movements that slipped the spoon into his mouth.*In essence, this pleasure system highlights whatever triggered it, prompts you to pursue those rewards again, and strengthens the behaviors that make you successful in getting them. It works hand in hand with the dopamine-based system. For example, slaking your thirst feels good both because the discontent of low dopamine leaves, and because the pleasure chemical–based joy of cool water on a hot day arrives.