Figure 1. Schematic horizontal section through the brainstem. The lateral tegmental field is indicated in red. BC, brachium conjunctivum; BP, brachium pontis; CN, cochlear nuclei; nV, trigeminal nerve; Vm, motor trigeminal nucleus; Vpr, principle trigeminal nucleus; Vsp, spinal trigeminal nucleus; VII, facial nucleus; XII, hypoglossal nucleus.

Figure 2. Schematic overview of the brainstem in which the different systems are indicated by different colours. Aq, aqueduct; BaN, Barrington nucleus; BC, brachium conjunctivum; BIC, brachium of the inferior colliculus; BP, brachium pontis; CGLd, lateral geniculate body, dorsal part; CGM, medial geniculate body; CGMd, medial geniculate body, dorsal part; CGMp, medial geniculate body, principal part; CN, cochlear nuclei; CR, corpus restiforme; CS, superior colliculus; CSN, nucleus raphe centralis superior; CU, nucleus cuneatus; D, nucleus of Darkschewitsch; DGNA, dorsal group of the nucleus ambiguus; ECU, external cuneate nucleus; G, nucleus gracilis; IC, inferior colliculus; IN, interpeduncular nucleus; INC, interstitial nucleus of Cajal; IO, inferior olive; IVN, inferior vestibular nucleus; KF, nucleus Kölliker–Fuse; LL, lateral lemniscus; LRN, lateral reticular nucleus; LVN, lateral vestibular nucleus; MesV, mesencephalic trigeminal tract; ML, medial lemniscus; MLF, medial longitudinal fasciculus; motV, motor trigeminal nucleus; MTN, medial terminal nucleus; MVN, medial vestibular nucleus; NLL, nucleus of the lateral lemniscus; NOT, nucleus of the optic tract; NOTL, lateral nucleus of the optic tract; NOTM, medial nucleus of the optic tract; NPC, nucleus of the posterior commissure; NRA, nucleus retroambiguus; NRP, nucleus raphe pallidus; NRTP, nucleus reticularis tegmenti pontis; NTB, nucleus of the trapezoid body; NTS, nucleus tractus solitarius; nV, trigeminal nerve; nVII, facial nerve; OL, pretectal olivary nucleus; P, pyramidal tract; PAG, periaqueductal grey; PB, parabigeminal nucleus; PC, pedunculus cerebri; PON, pontine nuclei; PP, posterior pretectal nucleus; PTA, anterior pretectal nucleus; PTM, medial pretectal nucleus; Pul, pulvinar nucleus of the thalamus; RB, restiform body; RN, red nucleus; RP, nucleus raphe pallidus; RST, rubrospinal tract; S, solitary complex; SC, superior colliculus; SN, substantia nigra; SO, superior olivary complex; SVN, superior vestibular nucleus; Vsp, spinal trigeminal nucleus; Vsp tract, spinal trigeminal tract; Vspin caud, spinal trigeminal complex pars caudalis; VTN, ventral tegmental nucleus; III, oculomotor nucleus; IV, trochlear nucleus; VI, abducens nucleus; VII, facial nucleus; Xd, dorsal vagal nucleus; XII, hypoglossal nucleus.

Figure 3. Schematic transverse section through the C8 segment of the human spinal cord indicating the location of the various motor neuron cell groups.

Figure 4. Scheme of the motor system consisting of two components, the voluntary and the emotional motor system.

Figure 5. Schematic overview of the periaqueductal grey efferents and their possible functions.