KJ has paresis of the left lower face yet is able to close both eyes voluntarily and able to laugh and cry normally. Does she have an upper or motor neuron lesion affecting the facial muscle innervation?

The inability to voluntarily move the lower left face yet close the left eye voluntarily indicates a lesion in the upper motor neuron pathway from the right cerebral cortex because the upper motor neuron input to the facial nerve is contralateral. The upper motor neuron input is bilateral to the facial nerve that innervates the upper face, so an upper motor neuron lesion spares voluntary control of the upper face. A complete lower motor neuron lesion affecting the facial nerve would prevent all neural signals from reaching the muscles on one side of the face, so the person would be unable to close the ipsilateral eye and unable to contract any muscles on the affected side of the face.