Week 11 july 24 th , 2015. Touch: mechanical displacements and other physical impacts on the skin. Somatosensation: a collective term for sensory signals from the body. Cutaneous rabbit: two separate locations stimulated multiple times in quick succession feels like a rabbit, hopping across the skin between the two locations: investigated with fmri. Middle location equally activated as stimulated locations. Touch receptors: embedded in outer layer (epidermis) and underlying layer (dermis): multiple types of touch receptors, touch receptors (and other somatosensory receptors) have three attributes: Tactile receptors (four): mechanoreceptors: respond to mechanical stimulation or pressure. Ruffini endings: response characteristics of the mechanoreceptors: Fa i - meissner: skin slip; low-frequency vibration (3-40 hz). Fa ii pacinian: first contact with objects: high frequency vibration (50-700 hz). Sa i - merkel: fine spatial details, textures, patterns, braille; sustained pressure, spatial deformations (<5 hz). Sa ii - ruffini: lateral stretch (e. g. , grasping), hand shape; low sensitivity to vibration.