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the sensation produced through the action of mechanical stimuli on the surface of the skin. Tactile sensation, a form of the sense of touch, varies according to the type of stimulus: touch, pressure, or vibration.
Tactile stimuli are perceived by free nerve endings and by nerve plexuses around the hair follicles, as well as by Pacini’s, Meissner’s, and Merkel’s corpuscles. Several Merkel’s or Meissner’s corpuscles may be innervated by the same nerve fiber, constituting a unique tactile formation. Such encapsulated receptors as Pacini’s and Meissner’s corpuscles determine the threshold of tactile sensation; these receptors become stimulated by touch and vibration, and adapt rapidly. The sensation of pressure is produced by the stimulation of such slowly adapting receptors as free nerve endings.
In comparison with other skin sensations, tactile sensation decreases rapidly with prolonged stimulation, since, on the whole, the processes of adaptation in the tactile receptors are very rapid. The most highly differentiated tactile sensations are produced by stimulating the lips, the tip of the tongue, and the tips of the fingers, areas richly supplied with a variety of mechanical receptors. The cortical part of the tactile analyzer is represented in the postcentral and precentral gyri.
REFERENCESIl’inskii, O. B. “Fiziologiia kozhnoi chuvstvitel’nosti.” In Fiziologiia sensornykh sistem, part 2. (Rukovodstvopo fiziologii.) Leningrad, 1972.
Esakov, A. I., and T. M. Dmitrieva. Neirofiziologicheskie osnovy taktil’nogo vospriiatiia. Moscow, 1971.
O. B. IL’INSKII