The eyes, nose, ears, tongue and skin contain sensory receptors or specialized nerve endings that act as sense detectors. Sensory receptors transfer detected stimuli to regions of the brain that allow people to perceive the sensory information. The auditory cortex, visual cortex and sensory cortex are regions of the brain dedicated to sensory perception.
Auditory Cortex
The auditory cortex is located within the temporal lobe, or the brain region just above the ears. This region receives sensory information pertaining to sound from the sound receptors of the inner ear. Sound initially enters the primary auditory cortex, where pitch and low tones are perceived. Sound then travels to the secondary auditory cortex to discern the sound of words. Just adjacent to the secondary auditory cortex, Wernicke’s area deciphers the meaning of the words heard, according to the University of Utah Health Sciences Library.
Visual Cortex
The visual cortex, located in the occipital lobe at the back of the head, receives visual input from the optic nerves which originate from the retina of the eyes. The optic nerves transmit pieces of visual input, detected by the retina, initially to the primary visual cortex, or area V1. Area V1 then sends the visual input to other areas of the visual cortex, namely areas V2, V3 and V4. Each of these areas further develops the image until a complete visual image is perceived. The visual cortex only perceives an object's shape, color and movement direction; it does not perceive what the object is or where the object is in space--those characteristics are calculated by other regions of the brain, according to the University of Sussex School of Life Sciences.
Sensory Cortex
Stretching across the top of the head, from ear to ear, the primary sensory cortex, or S1, receives sensory information from the receptors in the skin and joints pertaining to touch, vibration, pressure, pain and proprioception, or the sense of balance. The sensory cortex is divided into successive regions, each responsible for specific sensory perception. The sensory cortex also houses the gustatory area which is associated with taste perception, according to the National Center for Biotechnology Information.
Olfactory Area
The olfactory area governs the sense of smell. Located in the orbitofrontal cortex, just above the eye socket, the olfactory area is associated with the limbic system, or areas of the brain that govern emotion. For that reason, specific odors can evoke powerful emotional responses, according to “Neuro 101: Neurophysiology Without Tears.”
References
- “Neuro 101: Neurophysiology Without Tears”; William MacKay; 1999
- University of Utah Health Sciences Library: Hyperbrain, the Auditory System
- University of Sussex School of Life Sciences: The Visual Cortex
- National Center for Biotechnology Information: The Somatic Sensory Cortex:
