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50-399: Touching may refer to: Touch , a sensation processed by the somatosensory system Physical intimacy , sensuous proximity or touching Music [ edit ] Touching (Paul Bley album) , 1965 Touching (Eric Alexander album) , 2012 Other [ edit ] T,O,U,C,H,I,N,G , Paul Sharits film, 1968 Topics referred to by

100-456: A peripheral neuropathy involving peripheral nerves of the somatosensory system. This may present as numbness or paresthesia . Haptic technology can provide touch sensation in virtual and real environments. In the field of speech therapy , tactile feedback can be used to treat speech disorders . Affectionate touch is present in everyday life and can take multiple forms. These actions, however, seem to carry specific functions even though

150-559: A constant or static stimulus, and the pulses will subside to a normal rate. Receptors that adapt quickly (i.e., quickly return to a normal pulse rate) are referred to as "phasic". Those receptors that are slow to return to their normal firing rate are called tonic . Phasic mechanoreceptors are useful in sensing such things as texture or vibrations, whereas tonic receptors are useful for temperature and proprioception among others. Cutaneous mechanoreceptors with small, accurate receptive fields are found in areas needing accurate taction (e.g.

200-428: A generator potential in the sensory neuron arising within it. This is a graded response: the greater the deformation, the greater the generator potential. If the generator potential reaches threshold, a volley of action potentials (nerve impulses) are triggered at the first node of Ranvier of the sensory neuron. Once threshold is reached, the magnitude of the stimulus is encoded in the frequency of impulses generated in

250-486: A small receptive field (extremely detailed information), they are used in areas like fingertips the most; they are not covered (shelled) and thus respond to pressures over long periods. Tactile corpuscles react to moderate vibration (10–50 Hz) and light touch. They are located in the dermal papillae ; due to their reactivity, they are primarily located in fingertips and lips. They respond in quick action potentials , unlike Merkel nerve endings. They are responsible for

300-430: Is a type of sensory information that elicits an emotional reaction and is usually social in nature, such as a physical human touch. This type of information is actually coded differently than other sensory information. Intensity of affective touch is still encoded in the primary somatosensory cortex and is processed in a similar way to emotions invoked by sight and sound, as exemplified by the increase of adrenaline caused by

350-453: Is better among adults with smaller index fingertips; this effect of finger size has been shown to underlie the better passive tactile spatial acuity of women, on average, compared to men. The density of tactile corpuscles , a type of mechanoreceptor that detects low-frequency vibrations, is greater in smaller fingers; the same may hold for Merkel cells , which detect the static indentations important for fine spatial acuity. Among children of

400-426: Is different from Wikidata All article disambiguation pages All disambiguation pages Touch Mechanosensory information includes that of light touch, vibration, pressure and tension in the skin. Much of this information belongs to the sense of touch which is a general somatic sense in contrast to the special senses of sight , smell , taste , hearing and balance . Nociceptory information

450-411: Is excited by stretch of the blood vessel. There are also juxtacapillary (J) receptors , which respond to events such as pulmonary edema , pulmonary emboli , pneumonia , and barotrauma . The knee jerk is the popularly known stretch reflex (involuntary kick of the lower leg) induced by tapping the knee with a rubber-headed hammer. The hammer strikes a tendon that inserts an extensor muscle in

500-472: Is important amongst some animals. Usually, tactile contact between two animals occurs through stroking, licking, or grooming. These behaviours are essential for the individual's social healthcare, as in the hypothalamus they induce the release of oxytocin, a hormone that decreases stress and anxiety and increases social bonding between animals. More precisely, the consistency of oxytocin neuron activation in rats stroked by humans has been observed, especially in

550-577: Is in the parietal lobe and its cortex is the primary somatosensory cortex ( Brodmann areas 3, 2 and 1 ) collectively referred to as S1. BA3 receives the densest projections from the thalamus . BA3a is involved with the sense of relative position of neighboring body parts and amount of effort being used during movement. BA3b is responsible for distributing somatosensory information, it projects texture information to BA1 and shape and size information to BA2. Region S2 ( secondary somatosensory cortex ) divides into Area S2 and parietal ventral area. Area S2

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600-494: Is involved in numerous functions. The somatosensory system is spread through all major parts of the vertebrate body. It consists both of sensory receptors and sensory neurons in the periphery (skin, muscle and organs for example), to deeper neurons within the central nervous system . All afferent touch/vibration information ascends the spinal cord via the dorsal column-medial lemniscus pathway via gracilis (T7 and below) or cuneatus (T6 and above). Cuneatus sends signals to

650-508: Is involved with specific touch perception and is thus integrally linked with the amygdala and hippocampus to encode and reinforce memories. Parietal ventral area is the somatosensory relay to the premotor cortex and somatosensory memory hub, BA5. BA5 is the topographically organized somato memory field and association area. BA1 processes texture info while BA2 processes size and shape information. Area S2 processes light touch, pain, visceral sensation, and tactile attention. S1 processes

700-538: Is that received from pain and temperature that is deemed as harmful (noxious). Thermoreceptors relay temperature information in normal circumstances. Nociceptors are specialised receptors for signals of pain. The sense of touch in perceiving the environment uses special sensory receptors in the skin called cutaneous receptors . They include mechanoreceptors such as tactile corpuscles that relay information about pressure and vibration; nociceptors, and thermoreceptors for temperature perception. Stimulation of

750-409: Is the pathway responsible for the sending of fine touch information to the cerebral cortex of the brain. Crude touch (non-discriminating) is a sensory modality that allows the subject to sense that something has touched them, without being able to localize where they were touched (contrasting "fine touch"). Its fibres are carried in the spinothalamic tract , unlike the fine touch, which is carried in

800-443: The central nervous system . Cutaneous mechanoreceptors respond to mechanical stimuli that result from physical interaction, including pressure and vibration. They are located in the skin, like other cutaneous receptors . They are all innervated by Aβ fibers , except the mechanorecepting free nerve endings , which are innervated by Aδ fibers . Cutaneous mechanoreceptors can be categorized by what kind of sensation they perceive, by

850-432: The central nervous system . Type II and Type III mechanoreceptors in particular are believed to be linked to one's sense of proprioception . Other mechanoreceptors than cutaneous ones include the hair cells , which are sensory receptors in the vestibular system of the inner ear , where they contribute to the auditory system and equilibrioception . Baroreceptors are a type of mechanoreceptor sensory neuron that

900-447: The ability of touch to have an unconscious influence on such higher-order thoughts may provide a novel tool for marketing and communication strategies. Mechanoreceptor A mechanoreceptor , also called mechanoceptor , is a sensory receptor that responds to mechanical pressure or distortion. Mechanoreceptors are innervated by sensory neurons that convert mechanical pressure into electrical signals that, in animals, are sent to

950-509: The ability to read Braille and feel gentle stimuli. Pacinian corpuscles determine gross touch and distinguish rough and soft substances. They react in quick action potentials, especially to vibrations around 250 Hz (even up to centimeters away). They are the most sensitive to vibrations and have large receptor fields. Pacinian corpuscles react only to sudden stimuli so pressures like clothes that are always compressing their shape are quickly ignored. They have also been implicated in detecting

1000-408: The caudal paraventricular nucleus. It was found that this affiliative relationship induced by tactile contact is common no matter the relationship between the two individuals (mother-infant, male-female, human-animal). It has also been discovered that the level of oxytocin release through this behaviour correlates with the time course of social interaction as longer stroking induced a greater release of

1050-551: The cochlear nucleus indirectly via spinal grey matter, this info is used in determining if a perceived sound is just villi noise/irritation. All fibers cross (left becomes right) in the medulla. A somatosensory pathway will typically have three neurons: first-order, second-order, and third-order. Photoreceptors, similar to those found in the retina of the eye , detect potentially damaging ultraviolet radiation ( ultraviolet A specifically), inducing increased production of melanin by melanocytes . Thus tanning potentially offers

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1100-420: The dorsal column. As fine touch normally works in parallel to crude touch, a person will be able to localize touch until fibres carrying fine touch (in the dorsal column–medial lemniscus pathway) have been disrupted. Then the subject will feel the touch, but be unable to identify where they were touched. The somatosensory cortex encodes incoming sensory information from receptors all over the body. Affective touch

1150-476: The evaluation of risks that occur during conducting such behaviours in the wild life, and further research is required to unveil the connection between tactile caring and fitness level. Studies show a correlation between touching a soft or hard object and how a person thinks or even makes decisions. Further, between the firmness of a touch and the evoking of gender stereotyping. Tactile memories as part of haptic memory , are organized somatotopically , following

1200-468: The evolutionary benefit from such a wide range of behaviours is not entirely understood. Researchers investigated the expression patterns and characteristics of 8 different affectionate touch actions - embracing, holding, kissing, leaning, petting, squeezing, stroking, and tickling - in a self-report study. It was found that the affectionate touch has distinct target areas on the body, different associated affect, comfort-value, and expression frequency based on

1250-579: The fingertips). In the fingertips and lips, innervation density of slowly adapting type I and rapidly adapting type I mechanoreceptors are greatly increased. These two types of mechanoreceptors have small discrete receptive fields and are thought to underlie most low-threshold use of the fingers in assessing texture, surface slip, and flutter. Mechanoreceptors found in areas of the body with less tactile acuity tend to have larger receptive fields . Lamellar corpuscles , or Pacinian corpuscles or Vater-Pacini corpuscle, are deformation or pressure receptors located in

1300-438: The front of the thigh into the lower leg. Tapping the tendon stretches the thigh muscle, which activates stretch receptors within the muscle called muscle spindles . Each muscle spindle consists of sensory nerve endings wrapped around special muscle fibers called intrafusal muscle fibers . Stretching an intrafusal fiber initiates a volley of impulses in the sensory neuron (a I-a neuron) attached to it. The impulses travel along

1350-402: The hormone. The importance of somatosensory stimulation in social animals such as primates has also been observed. Grooming is part of the social interaction primates exert on their conspecifics. This interaction is required between individuals to maintain the affiliative relationship within the group, avoid internal conflict and increase group bonding. However, such social interaction requires

1400-428: The location of objects which are sensed by the visual system (which provides confirmation of the place of those objects relative to the body), as input to the mechanical reflexes of the body. Fine touch (or discriminative touch) is a sensory modality that allows a subject to sense and localize touch. The form of touch where localization is not possible is known as crude touch. The dorsal column–medial lemniscus pathway

1450-509: The location of touch sensations on handheld tools. Bulbous corpuscles react slowly and respond to sustained skin stretch. They are responsible for the feeling of object slippage and play a major role in the kinesthetic sense and control of finger position and movement. Merkel and bulbous cells - slow-response - are myelinated ; the rest - fast-response - are not. All of these receptors are activated upon pressures that distort their shape causing an action potential. The postcentral gyrus

1500-466: The most rigorous being the grating orientation task. In this task subjects identify the orientation of a grooved surface presented in two different orientations, which can be applied manually or with automated equipment. Many studies have shown a decline in passive tactile spatial acuity with age; the reasons for this decline are unknown, but may include loss of tactile receptors during normal aging. Remarkably, index finger passive tactile spatial acuity

1550-527: The neuron. So the more massive or rapid the deformation of a single corpuscle, the higher the frequency of nerve impulses generated in its neuron. The optimal sensitivity of a lamellar corpuscle is 250 Hz, the frequency range generated upon finger tips by textures made of features smaller than 200  micrometres . There are four types of mechanoreceptors embedded in ligaments . As all these types of mechanoreceptors are myelinated , they can rapidly transmit sensory information regarding joint positions to

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1600-416: The organization of the somatosensory cortex. A variety of studies have measured and investigated the causes for differences between individuals in the sense of fine touch. One well-studied area is passive tactile spatial acuity, the ability to resolve the fine spatial details of an object pressed against the stationary skin. A variety of methods have been used to measure passive tactile spatial acuity, perhaps

1650-418: The physical sensation to its related conceptual processing. Indeed, it was found that different physical properties - weight, texture, and hardness - of a touched object can influence social judgement and decision-making. For example, participants described a passage of a social interaction to be harsher when they touched a hard wooden block instead of a soft blanket prior to the task. Building on these findings,

1700-580: The physical stimulus is preserved. In this way, neighboring neurons in the somatosensory cortex represent nearby locations on the skin or in the body, creating a map or sensory homunculus . Tactile signing is a common means of communication used by people with deafblindness . It is based on a sign language or another system of manual communication. Humans can communicate specific emotions through touch alone including anger, fear, disgust, love, gratitude, and sympathy via touch at much-better-than-chance levels. The two different types of mechanoreceptor in

1750-509: The prefrontal cortex is highly correlated with pleasantness scores of an affective touch. Inhibitory transcranial magnetic stimulation (TMS) of the primary somatosensory cortex inhibits the perception of affective touch intensity, but not affective touch pleasantness. Therefore, the S1 is not directly involved in processing socially affective touch pleasantness, but still plays a role in discriminating touch location and intensity. Tactile interaction

1800-420: The proprioceptors in the skin, muscles, and joints. The receptor for the sense of balance resides in the vestibular system in the ear (for the three-dimensional orientation of the head, and by inference, the rest of the body). Balance is also mediated by the kinesthetic reflex fed by proprioception (which senses the relative location of the rest of the body to the head). In addition, proprioception estimates

1850-413: The rate of adaptation, and by morphology. Furthermore, each has a different receptive field . Cutaneous mechanoreceptors can also be separated into categories based on their rates of adaptation. When a mechanoreceptor receives a stimulus, it begins to fire impulses or action potentials at an elevated frequency (the stronger the stimulus, the higher the frequency). The cell, however, will soon "adapt" to

1900-414: The receptors activate peripheral sensory neurons that convey signals to the spinal cord that may drive a responsive reflex , and may also be conveyed to the brain for conscious perception. Somatosensory information from the face and head enter the brain via cranial nerves such as the trigeminal nerve . The neural pathways that go to the brain are structured such that information about the location of

1950-505: The recognition of every member in the group. As such, it has been observed that the size of the neocortex is positively correlated with the size of the group, reflecting a limit to the number of recognizable members amongst which grooming can occur. Furthermore, the time course of grooming is related to vulnerability due to predation to which animals are exposed to whilst performing such social interaction. The relationship between tactile interaction, stress reduction and social bonding depends on

2000-411: The remaining info (crude touch, pain, temperature). BA7 integrates visual and proprioceptive info to locate objects in space. The insular cortex (insula) plays a role in the sense of bodily-ownership, bodily self-awareness, and perception. Insula also plays a role in conveying info about sensual touch, pain, temperature, itch, and local oxygen status. Insula is a highly connected relay and thus

2050-484: The role of the cutaneous mechanoreceptors for feedback in fine motor control . Single action potentials from Meissner's corpuscle , Pacinian corpuscle and Ruffini ending afferents are directly linked to muscle activation, whereas Merkel cell-neurite complex activation does not trigger muscle activity. Insect and arthropod mechanoreceptors include: Mechanoreceptors are also present in plant cells where they play an important role in normal growth, development and

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2100-531: The same age, those with smaller fingers also tend to have better tactile acuity. Many studies have shown that passive tactile spatial acuity is enhanced among blind individuals compared to sighted individuals of the same age, possibly because of cross modal plasticity in the cerebral cortex of blind individuals. Perhaps also due to cortical plasticity, individuals who have been blind since birth reportedly consolidate tactile information more rapidly than sighted people. A somatosensory deficiency may be caused by

2150-413: The same term [REDACTED] This disambiguation page lists articles associated with the title Touching . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Touching&oldid=1188960700 " Category : Disambiguation pages Hidden categories: Short description

2200-522: The sensing of their environment. Mechanoreceptors aid the Venus flytrap ( Dionaea muscipula Ellis) in capturing large prey. Mechanoreceptor proteins are ion channels whose ion flow is induced by touch. Early research showed that touch transduction in the nematode Caenorhabditis elegans was found to require a two transmembrane, amiloride -sensitive ion channel protein related to epithelial sodium channels (ENaCs). This protein, called MEC-4, forms

2250-448: The sensory axon to the spinal cord where they form several kinds of synapses : In somatosensory transduction , the afferent neurons transmit messages through synapses in the dorsal column nuclei , where second-order neurons send the signal to the thalamus and synapse with third-order neurons in the ventrobasal complex . The third-order neurons then send the signal to the somatosensory cortex . More recent work has expanded

2300-416: The skin and also in various internal organs. Each is connected to a sensory neuron. Because of its relatively large size, a single lamellar corpuscle can be isolated and its properties studied. Mechanical pressure of varying strength and frequency can be applied to the corpuscle by stylus, and the resulting electrical activity detected by electrodes attached to the preparation. Deforming the corpuscle creates

2350-504: The skin are termed low-threshold mechanoreceptors , and high threshold mechanoreceptors . The four mechanoreceptors in glabrous skin are low-threshold that respond to harmless stimuli. They are innervated by four different afferent fibers. High-threshold mechanoreceptors, respond to harmful stimuli . Merkel cell nerve endings are found in the basal epidermis and hair follicles ; they react to low vibrations (5–15  Hz ) and deep static touch such as shapes and edges. Due to having

2400-409: The skin rapid protection from DNA damage and sunburn caused by ultraviolet radiation (DNA damage caused by ultraviolet B ). However, whether this offers protection is debatable, because the amount of melanin released by this process is modest in comparison to the amounts released in response to DNA damage caused by ultraviolet B radiation. The tactile feedback from proprioception is derived from

2450-419: The social touch of a loved one, as opposed to the physical inability to touch someone you do not love. Meanwhile, the feeling of pleasantness associated with affective touch activates the anterior cingulate cortex more than the primary somatosensory cortex. Functional magnetic resonance imaging (fMRI) data shows that increased blood-oxygen-level contrast (BOLD) signal in the anterior cingulate cortex as well as

2500-466: The type of touch action that is performed. Besides the rather obvious sensory consequences of touch, it can also affect higher-level aspects of cognition such as social judgements and decision-making. This effect might arise due to a physical-to-mental scaffolding process in early development, whereby sensorimotor experiences are linked to the emergence of conceptual knowledge. Such links might be maintained throughout life, and so touching an object may cue

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