English
Noun
- The ventral portion of the midbrain, divided from the tectum by the cerebral aqueduct and the periaqueductal grey
- Containing the following nuclei: red nucleus, substantia nigra, ventral tegmental area
User Contributed Dictionary
References
Bear et al. Neuroscience, Exploring the Brain Co. 2001, Lippincot Williams and WilkinsExtensive Definition
The tegmentum (from Latin for "floor") is
a general area within the brainstem. It is located
between the ventricular
system and distinctive basal or
ventral structures at
each level. It is a multisynaptic network of neurons that is involved in many
unconscious homeostatic and reflexive pathways.
Development
In embryos the tegmentum is the anterior half of the neural tube. However, for fetuses to adults, tegmentum only refers to the parts of the brain that remains relatively unchanged after development is complete, i.e. at the brain stem and midbrain. Other parts, on the other hand, develop further, through folding and thickening, and have different names. Still, it is considered a continuous central region through all levels of the brainstem.Structures that develop to grow ventral or
lateral outside this primitive tube as add-ons (e.g. the crus cerebri
in the anterior of the midbrain) are not considered part of the
'tegmentum' as they are not part of the primitive neural tube but
grow as projections from the cerebral
cortex. Whereas, parts that were inside the primitive neural
tube and remained an integral part of it after complete development
(e.g. the red nucleus)
are considered part of the tegmentum.
Midbrain tegmentum
The midbrain tegmentum is the part of the midbrain extending from the substantia nigra to the cerebral aqueduct in a horizontal section of the midbrain.Pontine tegmentum
Lateral tegmental field
The lateral tegmental field (LTF) is the source of several neurons of the noradrenaline system of the brainOther
Other pertinent areas of the tegmentum are:References
tegmentum in French: Tegmentum
tegmentum in Russian: Покрышка среднего
мозга