a Stimulation: Stimulation or sensory excitation is the action of various agents or forms of energy (stimuli) on receptors that generate impulses that travel through nerves to the brain (afferents).b Perception: Perception is the mental process or state that is reflected in statements like “I see a uniformly blue wall’, representing awareness or understanding of the real-world cause of the sensory input. The goal of sensation is detection; the goal of perception is to create useful information of the surroundings.