<prompt> The fibre which is the thickest in human nerve isTouchPainTemperatureProprioception  <response>: Proprioception is carried by the thickest fibre A alpha 12-20 micrometer. Touch by A beta 5-12 umPain, temperature by A delta 2-5 um. Ref: Ganong;s Review of medical physiology;25th edition; pg: 94; table 4-1. 