Principles of Sensation
Sensation and perception work together to help you interact with the external world; neither one alone is sufficient to help you make sense of the world around you. Sensation is the bottom-up process of detecting information in the forms of energy (light, sound, heat, pressure, and others), and using a process of transduction to convert these energies into signals passed along the nerves to the brain. The brain then works to interpret these signals through a top-down process, applying previous experiences and expectations to make sense of the billions of bits of data that are constantly being taken in though the senses. Not all sensations are given equal attention. Much of the work of the brain and its process of perception rests in determining which sensations should be ignored, and which should receive the selective attention of consciousness.