Diencephalon
Division of the forebrain around the third ventricle
From Wikipedia, the free encyclopedia
In the human brain, the diencephalon (or interbrain[1]) is a division of the forebrain (embryonic prosencephalon). It is situated between the telencephalon and the midbrain (embryonic mesencephalon). The diencephalon has also been known as the tweenbrain in older literature.[2] It consists of structures that are on either side of the third ventricle, including the thalamus, the hypothalamus, the epithalamus and the subthalamus.
| Diencephalon | |
|---|---|
The hypothalamus and the right and left halves of the thalamus are labeled. The cerebellum is not part of the diencephalon. | |
| Details | |
| Precursor | Prosencephalon, derived from the neural tube |
| Part of | Human brain |
| Parts | Thalamus, the hypothalamus, the epithalamus and the subthalamus |
| Identifiers | |
| Latin | diencephalon |
| MeSH | D004027 |
| NeuroLex ID | birnlex_1503 |
| TA98 | A14.1.03.007 A14.1.08.001 |
| TA2 | 5661 |
| TH | H3.11.03.5.00001 |
| FMA | 62001 |
| Anatomical terms of neuroanatomy | |
The diencephalon is one of the main vesicles of the brain formed during embryonic development. During the third week of development a neural tube is created from the ectoderm, one of the three primary germ layers, and forms three main vesicles: the prosencephalon, the mesencephalon and the rhombencephalon. The prosencephalon gradually divides into the telencephalon (the cerebrum) and the diencephalon.
Structure
The diencephalon consists of the following structures:[citation needed]
- Thalamus
- Hypothalamus including the posterior pituitary
- Epithalamus which consists of:
- Anterior and posterior paraventricular nuclei
- Medial and lateral habenular nuclei
- Stria medullaris thalami
- Posterior commissure
- Pineal body
- Subthalamus
Attachments
The optic nerve (CNII) attaches to the diencephalon. The optic nerve is a sensory (afferent) nerve responsible for vision and sight; it runs from the eye through the optic canal in the skull and attaches to the diencephalon. The retina itself is derived from the optic cup, a part of the embryonic diencephalon.[citation needed]
Function
The diencephalon is the region of the embryonic vertebrate neural tube that gives rise to anterior forebrain structures including the thalamus,[3] hypothalamus,[3] posterior portion of the pituitary gland,[4] and the pineal gland.[4] The diencephalon encloses a cavity called the third ventricle.[3] The thalamus serves as a relay centre for sensory and motor impulses to and from the cerebrum, relaying sensory information from all senses besides smell.[5] The hypothalamus is located in the floor of the third ventricle, and has multiple functions including managing hormones in the endocrine system.[6]
Additional images
Diagram depicting the main subdivisions of the embryonic vertebrate brain. These regions will later differentiate into forebrain, midbrain and hindbrain structures.
Reconstruction of peripheral nerves of a human embryo of 10.2 mm. (Label for Diencephalon is at left.)
