Sense: Taste
Taste is one of the most common and fundamental of the senses of animals. It is the direct detection of chemical composition, usually through contact with chemoreceptor cells. Taste is very similar to olfaction (the sense of smell), in which the chemical composition of an organism's ambient medium is detected by chemoreceptors. In a liquid medium, taste is often used to describe this act as well.
In humans, the sense of taste is transduced by taste buds and is conveyed via three of the twelve cranial nerves. The facial nerve (VII) carries taste sensations from the anterior two thirds of the tongue, the glossopharyngeal nerve (IX) carries taste sensations from the posterior one third of the tongue while a branch of the vagus nerve (X) carries some taste sensations from the back of the oral cavity. Information from these cranial nerves is processed by the gustatory system.
As a general rule, taste is a global fuzzy assessment of the interaction of the fundamental taste systems of sweet, sour, bitter, salty, and umami. Location of the stimulus on the tongue is not important, despite the common misperception of a "taste map" of preference for different tastes in specific areas of the tongue [1]. In reality, the separate populations of taste buds sensing each of the basic tastes are distributed across the tongue.
If half of the tongue is blocked from sending information to the brain, people will report that a doubling of psychological perception has occurred for sweet, sour, salty, and bitter.
Source: Wikipedia