The corticobulbar tract directly innervates the nuclei for cranial nerves V, VII, IX, and XII. The corticobulbar tract also contributes to the motor regions of cranial nerve X in the nucleus ambiguus. See also Upper motor neuron Upper motor neuron lesion References External links http://thebrain.mcgill.ca/flash/i/i_06/i_06_cl/i_06_cl_mou/i_06_cl_mou.html http://pathology.mc.duke.edu/neuropath/nawr/motor-systems.html Central nervous system pathways Motor system Frontal lobe