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Human and Biomimetic Sensors
Published in Patrick F. Dunn, Fundamentals of Sensors for Engineering and Science, 2019
The sensors for touch, including pressure and vibration, are primary afferent nerve endings. These include Meissner corpuscles, Merkel receptors, Pacinian corpuscles, and Ruffini corpuscles (see Figure 3.13). Meissner corpuscles and Merkel receptors are located near the surface of the skin. The Meissner corpuscle, which is composed of dendrites contained within connective tissue, senses changes in texture and slow vibrations. The Merkel receptor, which has expanded dendrites, senses touch and sustained pressure. Pacinian corpuscles and Ruffini corpuscles are located in deeper layers of the skin. The Pacinian corpuscle, which consists of a single nerve ending contained within connective tissue, senses deep pressure and fast vibration. The Ruffini corpuscle, which has expansive nerve endings in a capsule of tissue, senses sustained pressure. Each sensor has a different sensory area, with the Meissner corpuscle having the smallest.
Whole Body Vibration, Cognition, and the Brain
Published in Redha Taiar, Christiano Bittencourt Machado, Xavier Chiementin, Mario Bernardo-Filho, Whole Body Vibrations, 2019
Eddy A. van der Zee, Marelle Heesterbeek, Oliver Tucha, Anselm B. M. Fuermaier, Marieke J. G. van Heuvelen
The skin contains many specialized mechanoreceptors that subserve “touch” sensations contributing to proprioception and motor control. Mechanoreceptors located in various layers of the skin are excited by indentation of the skin by their preferred stimulus (for example vibrations, stretching of the skin or brushing). This is followed by transferring the information to the brain via the spinal cord reaching the thalamus. From there, the information is conveyed to the sensory areas of the neocortex and other areas in the basal forebrain, cerebellum and brainstem. The four types present in the glabrous skin are the Meissner and Pacinian corpuscles, Merkel cell-neurite complexes and Ruffini endings. Most likely all these types of cutaneous mechanoreceptors respond to WBV in their own way. Meissner and Pacinian corpuscles are fast-adapting types, mainly responding at the start and the end of the skin indentation. Both respond strongly to vibratory stimuli, but the Pacinian corpuscles respond predominantly to vibration frequencies exceeding 400 Hz (but also detect vibrations starting from 150 Hz). In contrast, Meissner corpuscles are sensitive to much lower frequencies, especially those of 20–40 Hz (Roudat et al., 2012 and references therein). The Merkel cell-neurite complexes and Ruffini endings are slow-adapting types, responding for a longer duration to a continuous skin indentation. These mechanoreceptors mainly respond to stretching of the skin or brushing.
How we sense objects and energy
Published in Karl H.E. Kroemer, Fitting the Human, 2017
The most common type of tactile sensors is a free nerve ending, a proliferation of a nerve that dwindles in size and then disappears. Thousands of such tiny fibers extend through the layers of the skin. They respond particularly to mechanical displacements and are most sensitive near hair follicles. In smooth and hairless skin, encapsulated receptors are also common and are shown in Figure 7.2. Among these are the Meissner and the similar Merkel corpuscles; both respond to pressure. They are especially numerous in the ridges of the fingertips. The Pacinian corpuscle is an encapsulated nerve ending of a single, dedicated nerve fiber. These highly responsive tactile receptors are densely located in the palmar sides of the hand and the fingers and in distal joints. They are also prevalent near blood vessels, at lymph nodes, and in joint capsules. Krause end bulbs are particularly sensitive to cold but probably respond to other stimuli as well.
Tactile perception of skin: research on late positive component of event-related potentials evoked by friction
Published in The Journal of The Textile Institute, 2020
Wei Tang, Xiangyong Lu, Si Chen, Shirong Ge, Xianghong Jing, Xiaoyu Wang, Rui Liu, Hua Zhu
Tactile perception is a complex process that depends on surface properties (Hollins, Bensmaïa, & Washburn, 2001; Hollins & Risner, 2000). Friction plays an important role in tactile perception and is mediated by skin vibrations generated from tangential forces between the skin and surface (Chen, Ge, Tang, Zhang, & Chen, 2015). When a finger scans the surface of fabrics, the deformations and vibrations produced by friction forces stimulate sensory receptors in the skin. The Pacinian corpuscle is the main receptor that senses and transforms the skin vibrations to nerve action potentials, which have a frequency of 20–700 Hz (Bensmaïa & Hollins, 2005; Loewenstein, 1971; Mountcastle, LaMotte, & Carli, 1972).
Vibrotactile sensitivity testing for occupational and disease-induce peripheral neuropathies
Published in Journal of Toxicology and Environmental Health, Part B, 2021
The VPT test assesses the responses of specific sensory receptors using the vibration of different frequencies and amplitudes. The primary cutaneous receptors that respond to vibration include the Pacinian and Meissner corpuscles (Hendry, Hsiao, and Bushnell 1999; Johansson and Valbo 1983; Morioka and Griffin 2002). However, other receptors including Ruffini endings and Merkle disks, which respond to the sensation of roughness and light touch, also contribute to the detection of vibration (Brammer et al. 2010). In healthy individuals, the Pacinian corpuscles respond to vibrating stimuli with a dominant frequency that is between 60 and 300 Hz but tend to be most responsive to stimuli in the 100–300 Hz range. In addition, the amplitude of the stimulus that results in an action potential decreases as the frequency used to stimulate the receptors approaches the frequency range in which the receptors demonstrate the greatest sensitivity (Gescheider et al. 2002). In contrast, the Meissner corpuscles respond to light touch or vibration in the lower frequency range (less than 40 Hz). The Meissner corpuscles, which respond to vibration frequencies below 40 Hz seem to play a less prominent role in sensing vibration. However, there are data indicating that because the responses of the Meissner corpuscles do not appear to be affected by temperature, assessing the responses of these receptors, may provide important information on the manner in which vibrotactile stimuli are affected by various exposures (Harazin and Harazin-Lechowska 2007). For example, because the VPT at 125 Hz is sensitive to both environmental temperature and body temperature, the receptors activated at this frequency may not only provide information regarding sensory function but also vascular function, while the Meissner corpuscles are only affected by sensory input. This should be taken into account when testing subjects or patients that also exhibit peripheral vascular disorders.