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Brain anatomy – forebrain, midbrain, hindbrain. The cerebral peduncles each form a lobe ventrally of the tegmentum, on either side of the midline. Beyond the midbrain, between the lobes, is the interpeduncular fossa, which is a cistern filled with cerebrospinal fluid [citation needed]. The majority of each lobe constitutes the cerebral crus.
Ten of the twelve pairs of cranial nerves either target or are sourced from the brainstem nuclei. [14]: 725 The nuclei of the oculomotor nerve (III) and trochlear nerve (IV) are located in the midbrain. The nuclei of the trigeminal nerve (V), abducens nerve (VI), facial nerve (VII) and vestibulocochlear nerve (VIII) are located in the pons.
The cuneate and gracile nuclei reside at the closed (lower) medulla, so the medial lemniscus is not formed at this level. Fibres from these nuclei will pass to the contralateral side of the brainstem, as the internal arcuate fibres. In the midbrain, it is situated dorsal to the substantia nigra, and medial to either red nucleus. [4]
Pontine nuclei; Pontine cranial nerve nuclei. Chief or pontine nucleus of the trigeminal nerve sensory nucleus (V) Motor nucleus for the trigeminal nerve (V) Abducens nucleus (VI) Facial nerve nucleus (VII) Vestibulocochlear nuclei (vestibular nuclei and cochlear nuclei) (VIII) Superior salivatory nucleus; Pontine tegmentum
Descending fibers arise from the superior colliculus in the rostral midbrain (for visual reflexes), the accessory oculomotor nuclei in the rostral midbrain for visual tracking, and the pontine reticular formation, which facilitates extensor muscle tone.
In neuroanatomy, the pretectal area, or pretectum, is a midbrain structure composed of seven nuclei and comprises part of the subcortical visual system.Through reciprocal bilateral projections from the retina, it is involved primarily in mediating behavioral responses to acute changes in ambient light such as the pupillary light reflex, the optokinetic reflex, and temporary changes to the ...
The brainstem, resembling a stalk, attaches to and leaves the cerebrum at the start of the midbrain area. The brainstem includes the midbrain, the pons, and the medulla oblongata. Behind the brainstem is the cerebellum (Latin: little brain). [7] The cerebrum, brainstem, cerebellum, and spinal cord are covered by three membranes called meninges.
The nucleus of the oculomotor nerve does not consist of a continuous column of cells, but is broken up into a number of smaller nuclei, which are arranged in two groups, anterior and posterior. Those of the posterior group are six in number, five of which are symmetrical on the two sides of the middle line, while the sixth is centrally placed ...