Back and central nervous system
Aida Lai in Essential Concepts in Anatomy and Pathology for Undergraduate Revision, 2018
Midbrain– two cerebral peduncles (ant. part = crus cerebri; post. part = tegmentum; substantia nigra sandwiched between ant. and post. parts)– tectum: sup. + inf. colliculi = corpora quadrigemina– pineal gland between sup. colliculi– colliculi situated posteriorly– superior colliculus = reflex centre associated with visual pathway: receives fibres from lat. geniculate body– inferior colliculus = reflex centre associated with auditory pathway: receives fibres from cochlear nuclei, connects to med. geniculate body on each side– red nucleus receives efferent fibres from cerebellum → sends to thalamus and spinal cord– periaqueductal grey (PAG) around cerebral aqueduct: suppression of pain by producing endorphin– substantia nigra between PAG and red nucleus
Brain Motor Centers and Pathways
Nassir H. Sabah in Neuromuscular Fundamentals, 2020
The tectospinal tract (Figure 11.3), also known as the colliculospinal tract, is an extrapyramidal motor tract that coordinates head, neck, and eye movements. The tract originates in the superior colliculus, which is situated rostrally, just below the thalamus (Figure 12.17). The superior colliculus, together with the inferior colliculus, comprise the tectum, or roof of the midbrain, in humans. The part of the midbrain between the tectum and tegmentum constitutes the midbrain tegmentum. The two colliculi on each side form four prominences referred to as the corpora quadrigemina.
Central nervous system
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha in Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
The midbrain is situated between the cerebrum and the pons. The ventral portion contains two cerebral peduncles that are composed mainly of fibres passing between the forebrain and the hindbrain. The dorsal portion contains four groups of cells, the corpora quadrigemina, which serve as reflex centres for movements of the eye, head and trunk, in response to visual and auditory stimuli. There is a narrow canal within the midbrain, termed the aqueduct of Sylvius, which communicates with the third ventricle above and the fourth ventricle below (Fig. 11.2b).
Cortical epileptogenesis and David Ferrier
Published in Journal of the History of the Neurosciences, 2018
Mervyn Eadie
Until 1870, animal experimentation had provided evidence that was interpreted as showing that convulsive epileptic seizures originated in the brainstem (Flourens, 1824; Marshall Hall, 1836; Kussmaul & Tenner, 1859; Schroeder van der Kolk, 1859; Nothnagel, 1868), and Brown-Séquard (1860) had described his so-called spinal epilepsy. The only experimental evidence that ran contrary to this interpretation was provided by Robert Bentley Todd (1809–1860). Todd (1849) first excluded epileptiform seizures from his consideration and then, based on briefly described experiments in rabbits, proposed that epilepsy depended on an event like a discharge of static electricity that occurred in the cerebral hemispheres. This caused loss of consciousness. If the discharge reached the level of the corpora quadrigemina, bilateral tonic spasm occurred, followed by bilateral clonic jerking if the discharge spread to the medulla oblongata.
Chameleons, red herrings, and false localizing signs in neurocritical care
Published in British Journal of Neurosurgery, 2022
Boyi Li, Tolga Sursal, Christian Bowers, Chad Cole, Chirag Gandhi, Meic Schmidt, Stephan Mayer, Fawaz Al-Mufti
Parinaud’s Syndrome, characterized by paralysis of vertical eye movements, is typically indicative of a lesion in the mesencephalon around the cerebral aqueduct and involving the corpora quadrigemina and posterior commissure.64 However, Parinaud’s syndrome has been reported as a FLS since 1899, with various case reports emerging in the 1960s and 1970s.64 A classic example of Parinaud’s syndrome is as a FLS for Pseudo-Dandy Walker Syndrome.64 Patients may present with headaches and several ocular difficulties including diplopia, difficulty with convergence, alternating fixation, and paralysis of upward eye movement, but normal corneas, visual acuity with correction, and visual fields.64 If CT and angiography are normal and cerebellar tumor excluded, iodo-ventriculography can be useful in looking for a potentially dilated and anteriorly displaced 4th ventricle past which the dye does not progress.64 4th ventricular outflow obstruction, caused by thickening of brain tissue may cause a Pseudo-Dandy Walker syndrome.64 Neurosurgical treatment of the stenosis should resolve the ocular signs.64 Thus, CSF flow is an important consideration in diagnosing cases that present with ocular symptoms such as Parinaud’s syndrome.
The ‘worm’ in our brain. An anatomical, historical, and philological study on the vermis cerebelli
Published in Journal of the History of the Neurosciences, 2023
Klaus F. Steinsiepe
Galen described the relationships between the vermis of the cerebellum, the aqueduct, and the fourth ventricle in detail: Then the duct which comes through from the middle to the posterior ventricle, between the gloutia,4Gloutia, from Greek gloutós, lat. nates, English (little) buttocks. Galen offered two interpretations: “On each side of the canal there are delicate, elongate eminences of the encephalon, called gloutia (little buttocks) [the corpora quadrigemina]. … There are those who liken them to the testicles and prefer to call them didymia (little testicles, or twins) rather than gloutia. Some call didymia the bodies associated with the pineal body [the upper colliculi], and gloutia the bodies that come next after these [the lower colliculi]” (De usu partium, transl. May 1968, 420). Because the pineal gland for Vesalius looked like a penis, he strictly named the superior colliculi testes, and the inferior colliculi gloutia (“On the testes and buttocks of the cerebrum,” Fabrica Book 7, Chap. 9 and Figure 10; see Garrison and Hast 2014, 1291; 1244). Galen, however, seems to be less strict, although in ruminants these superior colliculi of the quadrigeminal plate are much more pronounced than the inferior ones, see Figure 2 (cf. Rocca 2003, 154, note 191). Sissons and Grossman (1975, 1074) wrote, “Of the paired colliculi of the lamina tecti the caudal pair are by far the smaller (Fig. 35–7 and 8).” is covered by its own tunic. … Lying on it is a circumscribed part of the brain, having an outward appearance like the worm which grows in wood. And thence the custom by anatomists to call the body covering all the duct the vermiform outgrowth. [De anatomicis administrationibus IX. (Kühn II 1821, 729f.; transl. Rocca 2003, 153f)