Is it ensure, insure, or assure?
supranuclear su·pra·nu·cle·ar (sōō'prə-nōō'klē-ər, -nyōō'-)
Located above the level of the motor neurons of the spinal or cranial nerves. Used to indicate disorders of movement caused by destruction or functional impairment of brain structures, such as the motor cortex, pyramidal tract, or corpus striatum.
Of or relating to the part of a cell between the nucleus and the distal border.