In the human brain , the diencephalon (or interbrain ) 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. It consists of structures that are on either side of the third ventricle , including the thalamus , the hypothalamus , the epithalamus and the subthalamus .
6-399: The diencephalon is one of the main vesicles of the brain formed during embryogenesis . During the third week of development a neural tube is created from the ectoderm , one of the three primary germ layers . The tube forms three main vesicles during the third week of development: the prosencephalon , the mesencephalon and the rhombencephalon . The prosencephalon gradually divides into
12-415: A part of the embryonic diencephalon. The diencephalon is the region of the embryonic vertebrate neural tube that gives rise to anterior forebrain structures including the thalamus , hypothalamus , posterior portion of the pituitary gland , and the pineal gland . The diencephalon encloses a cavity called the third ventricle. The thalamus serves as a relay centre for sensory and motor impulses between
18-650: The bulge-like enlargements of the early development of the neural tube in vertebrates , which eventually give rise to the brain . Vesicle formation begins shortly after the rostral closure of the neural tube, at about embryonic day 9.0 in mice , or the fourth and fifth gestational week in humans . In zebrafish and chicken embryos, brain vesicles form by about 24 hours and 48 hours post-conception, respectively. Initially there are three primary brain vesicles : prosencephalon (i.e. forebrain ), mesencephalon (i.e. midbrain ) and rhombencephalon (i.e. hindbrain ). These develop into five secondary brain vesicles –
24-445: The prosencephalon is subdivided into the telencephalon and diencephalon , and the rhombencephalon into the metencephalon and myelencephalon . During these early vesicle stages, the walls of the neural tube contain neural stem cells in a region called the neuroepithelium or ventricular zone . These neural stem cells divide rapidly, driving growth of the early brain, but later, these stem cells begin to generate neurons through
30-449: The spinal cord and medulla oblongata, and the cerebrum. It recognizes sensory impulses of heat, cold, pain, pressure etc. The floor of the third ventricle is called the hypothalamus. It has control centres for control of eye movement and hearing responses. [REDACTED] This article incorporates text in the public domain from page 807 of the 20th edition of Gray's Anatomy (1918) Brain vesicle Brain vesicles are
36-404: The telencephalon (the cerebrum ) and the diencephalon. The diencephalon consists of the following structures: 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 ,
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