A-alpha fibers are the thickest and transmit proprioceptive signals from skeletal muscle. A-beta fibers are thick and transmit touch and proprioceptive signals from deeper skin. A-delta fibers are medium-sized and transmit sharp, stabbing pain and signals about cold temperature. Unmyelinated C fibers are the thinnest and transmit signals about burning pain, aching pain, itch, and warm temperature sensations from the deepest layers of skin.