External stimulation such as light, sound, movement, chemicals. Internally the sensory receptors, that are located within the sense organs-eyes, ears, nose, skin and tongue-will be activated by this energy stimulation and will convert the energy into electrical impulses that will reach the central nervous system. Each sense organ will stimulate different parts of the brain. When considering light, it is an external energy that will enter the eye through the cornea to the retina; there the photoreceptors (cones and rods) will convert the energy into nerve impulses that will travel to the visual cortex. Two important pathways of light are: 1) visual cortex to the cerebral cortex and 2) visual cortex to the limbic system. The cerebral cortex will interpret what color and form means to the individual. It will then lead to higher executive analysis. The limbic system is the home of our primitive emotions. The goal of working with clients with brain injury is to bring the nervous system back into homeostasis. Each case needs careful consideration towards potential psychological and physical duress when designing treatment goals. Sensory stimulation is a powerful tool that needs to be used carefully.