page_title: Tactile discrimination
section_title: Blindness
hierarchical_section_title: Tactile discrimination / Applications / Blindness
caption_attribution_description: ATM keypad with braille.
context_page_description: Tactile discrimination is the ability to differentiate information through the sense of touch. The somatosensory system is the nervous system pathway that is responsible for this essential survival ability used in adaptation. There are various types of tactile discrimination. One of the most well known and most researched is two-point discrimination, the ability to differentiate between two different tactile stimuli which are relatively close together. Other types of discrimination like graphesthesia and spatial discrimination also exist but are not as extensively researched. Tactile discrimination is something that can be either more or less severe in different people and two major conditions, chronic pain and blindness, can affect it greatly. Blindness increases tactile discrimination abilities which is extremely helpful for tasks like reading braille. In contrast, chronic pain conditions, like arthritis, decrease a person's tactile discrimination. One other major application of tactile discrimination is in new prosthetics and robotics which attempt to mimic the abilities of the human hand.
context_section_description: When a person has become blind, in order to “see” the world, their other senses become heightened. An important sense for the blind is their sense of touch, which becomes more frequently used to help them perceive the world. People that are blind have displayed that their visual cortices become more responsive to auditory and tactile stimulation. Braille allows the blind to be able to use their sense of touch to feel the roughness, and distance of various patterns to be used as a form of language. Within the brain, the activation of the occipital cortex is functionally relevant for tactile braille reading, as well as the somatosensory cortex. These various parts of the brain function in their own way, in which they each contribute to the effectiveness of how braille is read by the blind. People that are blind also rely heavily on Tactile Gnosis, Spatial discrimination, Graphesthesia, and Two-point discrimination. Essentially, the occipital cortex allows one to effectively make judgements on the distance of braille patterns, which is related to spatial discrimination. Meanwhile, the somatosensory cortex allows one to effectively make judgements on the roughness of braille patterns, which is related to two-point discrimination. The various visual areas in the brain are very essential for a blind person to read braille, just as much as it is for a person that has sight. Essentially, whether one is blind or not, the perception of objects that involves tactile discrimination is not impaired if one cannot see. When comparing people that are blind to people that have sight, the amount of activity within their somatosensory and visual areas of the brain do differ. The activity in the somatosensory and visual areas are not as high in tactile gnosis for people that are not blind, and are more-so active for more visual related stimuli that does not involve touch. Nonetheless, there is a difference in these various areas within the brain when comparing the blind to the sighted, which is that shape discrimination causes a difference in brain activity, as well as tactile gnosis. The visual cortices of blind individuals are active during various vision related tasks including tactile discrimination, and the function of the cortices resemble the activity of adults with sight.
caption: Common Keypad with Braille
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