corticonuclear / corticobulbar systems - nuclei input descritions

oculomotor nucleus

bilateral, indirect
CN III, eye movement, midbrain
frontal eye fields — posterior portion of anterior limb of internal capsule —> synapse —> oculomotor nucleus —> LMN (CN III)

trochlear nucleus

bilateral, indirect
CN IV, eye movement, midbrain

FEF — posterior portion of anterior limb —> synapse —> trochlear nucleus —> LMN (CN IV)

trigeminal motor nucleus

bilateral, direct and indirect
CN V, biting and chewing (BE), pons
inferior precentral gyrus (face) — genu of IC —> (synapse) —> trigeminal motor nucleus —> LMN (CN V)

abducens nucleus

bilateral, indirect
CN VI, eye movement, pons / medulla junction
Precentral gyrus —genu of internal capsule —> synapse (paramedian pontine reticular formation) —> abducens nucleus —> LMN (CN VI)

facial nucleus

temporal facial muscles (upper): bilateral, direct and indirect
inferior facial miscles (lower): contralateral, direct and indirect
CN VII, facial expressions (BE), pons/medulla junction
facial areas of motor cortex — genu of IC —> (synapse) —> facial nucleus —> LMN (CN VII)

nucleus ambiguous

contralateral, indirect
CN IX, X, speech/swallowing (BE), medulla
cortex — genu, cross —> reticular formation (synapse) —> nucleus ambiguous —> LMN —> uvula skeletal muscle (pulls ipsilateral)

hypoglossal nucleus

contralateral, direct and indirect
CN XII, tongue movement, medulla
cortex — genu (cross) —> (synapse) —> hypoglossal nucleus —> LMN —> tongue skeletal muscle (pushes contralateral)

accessory nucleus

ipsilateral, direct and indirect
CN XI, head turning (BE), cervical spinal cord to medulla
cortex — genu of IC —> (synapse) —> accessory nucleus