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Midbrain

The midbrain or mesencephalon (from the Greek mesos, middle, and enkephalos, brain is a portion of the central nervous system associated with vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation.

The midbrain comprises the tectum (or corpora quadrigemina), tegmentum, the cerebral aqueduct (or ventricular mesocoelia or “iter”), and the cerebral peduncles, as well as several nuclei and fasciculi. Caudally the midbrain adjoins the metencephalon (afterbrain) (pons and cerebellum) while rostrally it adjoins the diencephalon (thalamus, hypothalamus, etc.). The midbrain is located below the cerebral cortex, and above the hindbrain placing it near the center of the brain.

Specifically, the midbrain consists of:

Tectum

Inferior colliculus

Superior colliculus

Cerebral peduncle

Midbrain tegmentum

Crus cerebri

Substantia nigra.


Dopaminergic neurons of the midbrain are the main source of dopamine (DA) in the mammalian central nervous system.

Pathology

Midbrain MRI

In a prospective longitudinal design, Hirad et al. demonstrated there are reductions in midbrain white matter integrity due to a single season of collegiate football, and that the amount of reduction in midbrain white matter integrity is related to the amount of rotational acceleration to which players' brains are exposed. We then replicate the observation of reduced midbrain white matter integrity in a retrospective cohort of individuals with frank concussion, and further show that variance in white matter integrity is correlated with levels of serum-based tau, a marker of blood-brain barrier disruption. These findings mean that noninvasive structural MRI of the midbrain is a succinct index of both clinically silent white matter injury as well as frank concussion 1).

1)
Hirad AA, Bazarian JJ, Merchant-Borna K, Garcea FE, Heilbronner S, Paul D, Hintz EB, van Wijngaarden E, Schifitto G, Wright DW, Espinoza TR, Mahon BZ. A common neural signature of brain injury in concussion and subconcussion. Sci Adv. 2019 Aug 7;5(8):eaau3460. doi: 10.1126/sciadv.aau3460. eCollection 2019 Aug. PubMed PMID: 31457074; PubMed Central PMCID: PMC6685720.
midbrain.txt · Last modified: 2019/08/30 09:23 by administrador