“Your brain maintains a complete map of your body’s surface, with patches devoted to each finger, hand, cheek, lip, eyebrow, shoulder, hip, knee, and all the rest. This map is your primary physical window on the world around you, the entry point for all the raw touch information streaming moment by moment into your brain.”
Somatic Sensation: bodily sensations of touch, pain, temperature, vibration, and proprioception. (Blumenfeld, 276) The process by which the nature and meaning of tactile stimuli are recognized and interpreted by the brain, such as realizing the characteristics or name of an object being touched. (MeSH) (Includes) the sensation produced by pressure receptors in the skin. (NCIt)
The somatosensory system tells us what the body is up to and what’s going on in the “environment” by providing information about bodily sensations, such as touch, temperature, pain, position in space, and movement of the joints. Unique among sensory systems. It is not localized in the head as are vision, hearing, taste, and smell, but rather is distributed throughout the entire body. (Kolb, 368) Also referred to as 'sensory system,’ 'somatosensory system,’ and ‘somatosensation.’
Exteroception: replays sensory information about the body's interaction with the external environment. (Patestas, 137) The ability to perceive the world outside the self. (Blakeslee, 212)
Interoception: relays information about the body's internal state. (Patestas, 137) The ability to read and interpret sensations arising from the "viscera" and internal tissues of (the) body. (Blakeslee, 213)
Nociception: somatic sense of pain. (Blakeslee, 8) The stimulus-response process involving the stimulation of peripheral pain-carrying nerve fibers and the transmission of impulses along peripheral nerves of the “central nervous system,” where the stimulus is perceived as pain. (NCIt)
Proprioception: perception of the position and movement of the body, limbs, and head. (Kolb, 371) (The) sense (of) things inside our own bodies, especially the positions of our joints and muscles in space and the tension they are under. Essential for coordinated movement. Relies on (a) set of specialized nerve fibers that innervate the joints and muscles. (Mitchell, 135) Conveys information about position sense from the body and its component parts. (Patestas, 137) Somatic sense of (the) body's position and motion in space. (Blakeslee, 9) Without proprioception, we would be unable to point to an area of our body with our eyes closed or take a step without looking at our feet. (Kandel4, 60) When you learn a new sport, you re-hone this body sense through practice. (Blakeslee, 29)
Somatic Pathways: there are two main pathways for somatic sensation leading from “somatosensory receptors” through the “thalamus,” to the “primary somatosensory cortex.” (Blumenfeld, 276) Two major pathways in the "spinal cord" carry "inputs" from somatosensory receptors to the brain. One, evolutionarily older, carries pain, temperature, itch, tickle, sexual sensation, and 'crude touch' inputs. The evolutionarily newer one carries 'fine touch' information, position and location. (Blakeslee, 8) In a sensory pathway, information is transmitted from the first sensory neuron to specific and specialized neurons in the "spinal cord" or in the brain. (Kandel, 79)
Anterolateral Pathway: conveys pain, temperature sense, and crude touch. (Blumenfeld, 276) Has a 'somatotopic' organization in which the feet are most laterally represented (Blumenfeld, 280)
Posterior Column-Medial Lemniscal Pathway: conveys proprioception, vibration sense, and fine, discriminative touch. (Blumenfeld, 276)
Stereognosis: the ability to recognize the three-dimensional shape of an object by touch alone. (OxfordMed) Perception of (the) shape and form of objects by touch, via tactile stimuli. (MeSH)
Touch: the faculty of perceiving by physical contact with the body. The sensation produced by touching something. (Oxford) Each hair on the human body is very sensitive to touch, allowing us to detect an even very slight displacement. Some hairs are sensitive to displacement in one direction only, whereas others respond to displacement in any direction. When a hair is mechanically displaced, the “dendrite” encircling it is stretched, initiating the opening of a series of stretch-sensitive “channels” in the dendrite’s membrane. When these channels open, (they)… initiate the nerve “impulse.” (Kolb, 136) Also referred to as 'tactile perception.'
Hapsis: the perception of fine touch and pressure. The perception of objects that we grasp and manipulate or that contact the body. (Kolb, 370)
Thermoception: somatic sense for warmth and or cold. Uses "receptor" cells that are located in (the) skin. (Blakeslee, 8)