Upper motor neuron lesion affected to face (motor)

• General somatic efferent(GSE) supply to the face is by facial nerve.Main motor nucleus that carries GSE fibers to the facial muscles is located at lower pons lateral to the abducent nucleus.GSE path way begins from the primary motor cortex ,fibers from motor cortex connected to its cell in thalamus this is upper motor neuron. upper motor nuron fibers goes to opposite side main motor nucleus ,some fibers goes to same side facial nucleus.lower motor neuron is located in lower pons as facial nucleus. fibers from opposite cortex to the nucleus are supplied to the lower quadrant of the contralateral face(that's means opposite cerebral cortex supplies lower quadrant of the facial muscles)upper quadrant of facial muscles receive impulses from both motor cortex as mentioned above.
• so if there is a upper motor neuron lesion contralateral side of the lower quadrant  facial muscles get weaken.