Internal arcuate fibers are the axons of second-order neurons contained within the gracile and cuneate nuclei of the medulla oblongata. These fibers cross from one side of the medulla to the other to form the medial lemniscus. Part of the dorsal column-medial lemniscus system (second neuron), the internal arcuate fibers are important for relaying the sensation of fine touch and proprioception to the thalamus and ultimately to the cerebral cortex. [ http://en.wikipedia.org/wiki/Internal_arcuate_fibers ]