The medial longitudinal fasciculus (MLF) is a prominent bundle of nerve fibres which pass within the ventral/anterior portion of periaqueductal gray of the mesencephalon (midbrain). It contains the interstitial nucleus of Cajal, responsible for oculomotor control, head posture, and vertical eye movement.
The trapezoid body or ventral acoustic stria is a structure in the pontine tegmentum formed by the crossing-over (decussation) of a portion of the efferent second-order fibers of the ventral cochlear nucleus. After decussating, some of these fibres proceed to ascend in the contralateral lateral lemniscus to reach and terminate in the dorsal nucleus of lateral lemniscus, and inferior colliculus.
The rubrospinal tract is one of the descending tracts of the spinal cord. It is a motor control pathway that originates in the red nucleus. It is a part of the lateral indirect extrapyramidal tract.
The globose nucleus is one of the deep cerebellar nuclei. It is located medial to the emboliform nucleus, and lateral to the fastigial nucleus. The globose nucleus and emboliform nucleus are known collectively as the interposed nuclei.
The accessory cuneate nucleus is a nucleus situated in the caudal medulla oblongata just lateral to the cuneate nucleus. It relays unconscious proprioceptive sensory information from the upper limb and upper trunk to the cerebellum via the cuneocerebellar fibers.
The dorsal longitudinal fasciculus (DLF) is a nerve fiber tract extending from the hypothalamus rostrally to the spinal cord caudally. It containins both descending and ascending fibers. Its fibers form a distinct bundle in the midbrain.
The gigantocellular reticular nucleus is the (efferent/motor) medial zone of the reticular formation of the caudal pons and rostral medulla oblongata. It consists of a substantial number of giant neurons, but also contains small and medium sized neurons.
The vestibulocerebellar tract fibers are second-order fibers from the vestibular nuclei, and first-order fibers from the vestibular ganglion/nerve. They pass through the juxtarestiform body of the inferior cerebellar peduncle to reach the cerebellum, They terminate in the vestibulocerebellum, and part of the vermis as well as the dentate nucleus, and fastigial nucleus in each hemisphere They are involved in maintaining balance.
The spinoreticular tract is a partially decussating (crossed-over) four-neuron sensory pathway of the central nervous system. The tract transmits slow nociceptive/pain information from the spinal cord to reticular formation which in turn relays the information to the thalamus via reticulothalamic fibers as well as to other parts of the brain. Most (85%) second-order axons arising from sensory C first-order fibers ascend in the spinoreticular tract - it is consequently responsible for transmitting "slow", dull, poorly-localised pain. By projecting to the reticular activating system (RAS), the tract also mediates arousal/alertness in response to noxious (harmful) stimuli. The tract is phylogenetically older than the spinothalamic ("neospinothalamic") tract.
The anterior and posterior radicular arteries are 32 pairs of small/ variously sized arteries that enter an intervertebral foramen, bifurcating within it to form an anterior and a posterior radicular artery which accompany the anterior root and posterior root of a spinal nerve, respectively. They supply the corresponding spinal cord segment as well as the anterior and posterior root of the spinal nerve and its sensory ganglion.
The pontocerebellar fibers are the second-order neuron fibers of the corticopontocerebellar tracts that cross to the other side of the pons and run within the middle cerebellar peduncles, from the pons to the contralateral cerebellum. They arise from the pontine nuclei as the second part of the corticopontocerebellar tract, and decussate (cross-over) in the pons before passing through the middle cerebellar peduncles to reach and terminate in the contralateral posterior lobe of the cerebellum (neocerebellum). It is part of a pathway involved in the coordination of voluntary movements.
The dorsal trigeminal tract are uncrossed second-order sensory fibers conveying fine (discriminative) touch and pressure information from the dorsomedial division of principal sensory nucleus of trigeminal nerve to the ipsilateral ventral posteromedial nucleus of thalamus. Second-order fibers from the ventrolateral division of the principal sensory nucleus meanwhile cross-over to ascend contralaterally in the ventral trigeminal tract along with those fibers arising from the spinal trigeminal nucleus.
The central tegmental tract is a tract that carries ascending and descending fibers, situated in the midbrain tegmentum, and the pontine tegmentum. The tract is situated in the central portion of the reticular formation.
The epidural venous plexus is a venous plexus embedded within the epidural fat of the vertebral canal. It is situated within the anterior epidural space. The plexus extends from the skull base to the sacrum. It is surrounded by sparse fat. It drains into the cavernous sinus of the cranial cavity; it also communicates with the radicular veins.
The hypothalamospinal tract is an unmyelinated non-decussated descending nerve tract that arises in the hypothalamus and projects to the brainstem and spinal cord to synapse with pre-ganglionic autonomic neurons.
Radicular veins are segmental veins providing venous drainage of the spinal cord and canal. They communicate with anterior and posterior spinal veins as well as epidural venous plexus. They exit the spinal canal through the intervertebral foramina, accompanying the corresponding of radicular arteries.
The interstitial nucleus of Cajal is a collection of neurons in the mesencephalon (midbrain) which are involved in integrating eye position-velocity information in order to coordinate head-eye movements - especially those related to vertical and torsional conjugate eye movements (gaze). It also mediates vertical gaze holding.
The spinohypothalamic tract or spinohypothalamic fibers is a sensory fiber tract projecting from the spinal cord to the hypothalamus directly to mediate reflex autonomic and endocrine responses to painful stimuli (the hypothalamus receives additional indirect nociceptive projections from the reticular formation, and periaqueductal gray. The fibers of this tract synapse with hypothalamic neurons which in turn give rise to the hypothalamospinal tract that mediates the response of the autonomic nervous system to pain.
The dorsolateral pontine reticular formation contains noradrenergic pain-inhibiting neurons which project to inhibitory interneurons of the substantia gelatinosa of the posterior grey column in the spinal cord. It thus complements the classical serotonergic-opioid peptide descending pain-inhibiting system: whereas the serotonergic-opioid peptide pathway ultimately pre-synaptically inhibits first-order nociceptive group C neurons, the DLPRF inhibits - by way of presumably GABAergic inhibitory interneurons - the second-order neurons of the ascending pain pathway. The DLPRF pathway is not affected by opioid agonists or antagonists.
The spinomesencephalic pathway, spinomesencephalic tract or spino-quadrigeminal system of Mott, includes a number of ascending tracts in the spinal cord, including the spinotectal tract. The spinomesencephalic tract is one of the ascending tracts in the anterolateral system of the spinal cord that projects to various parts of the midbrain. It is involved in the processing of pain and visceral sensations.
