The role of the brain in perception is to process signals from various sense organs and give them meaning. Senses are sometimes categorized as either special senses or general senses. The special senses include visual and auditory perception. Other special senses are the sense of smell, taste and touch; perceptions of touch, pressure and temperature may be categorized as general senses.
Sight is an important special sense. Visual perception occurs when light waves enter the eye and stimulate visual receptors. These nerve impulses travel along the optic nerves; signals are sent to the visual cortex of the occipital lobe, which is used by the brain in perception visual sensory data.
Another key special sense is hearing or auditory perception, which is triggered by sound waves. Sound waves pass through sensory receptors in the ear and through the auditory nerve system. The waves are interpreted in the cerebrum’s temporal lobes, in the sections of the brain known as the auditory cortices.
Each nasal cavity in the nose has olfactory organs, which have receptors that are stimulated by odorant molecules. Odors seem to fade because the special sense of smell quickly adapts when exposed to the same odorant molecule for any length of time. Smells are interpreted in the olfactory cortex of the temporal lobes of the brain.
The special sense of taste is closely related to the sense of smell. Taste buds, which are sensory organs on the tongue, can detect a wide range of flavors ranging from sweet to salty. Bitter, sour and savory flavors can all be detected by taste buds. Chemicals in food and beverages stimulate the taste receptors while foods considered hot, such as spicy peppers, can also stimulate pain and heat receptors. The gustatory cortex of the cerebrum’s parietal lobes are used by the brain in perception of taste.
Some senses are categorized as general senses, including touch and pressure, which are stimulated when tissue has somehow shifted. Temperature is detected through heat and cold sensors. A body has widely distributed free nerve endings to sense pain while the cerebral cortex of the brain interprets the source and intensity of the pain, and how to respond to it.
Extrasensory perception (ESP) is way of knowing that is not explained through the known senses. Examples of ESP may include reading people’s minds or accurately predicting the future. Although many people believe that ESP exists, it has been difficult to prove using scientific methods, and the areas of the brain in perception of ESP stimulus have not be identified.