The brain tissue located above the midbrain and between the two cerebral hemispheres.The brain between the telencephalon and the midbrain is one on the left and one on the right, and the ventricle between them is the third ventricle.This room is connected to the midbrain aqueduct downwards and the lateral ventricle of the telencephalon via the interventricular foramen upwards.
Chinese name
Diencephalon
Foreign name
diencephalon
At
Above the brainstem, medial to the caudate nucleus and internal capsule
The structure is complex, including the hypothalamus, dorsal thalamus, posterior thalamus, subthalamic and hypothalamus.
(1)SuprathalamusThe main structure is the pineal gland, which is an endocrine gland.
(2) The dorsal thalamus consists of two oval gray matter masses, one on the left and one on the right.Each oval gray matter mass is further divided into the anterior thalamic nucleus, the medial thalamic nucleus and the lateral thalamic nucleus.The anterior nucleus of thalamus has functions related to visceral activities. The medial nucleus of thalamus may be the integration center of somatic and visceral sensory impulses. The lateral nucleus of thalamus is the last relay station of somatic sensory pathway, which transmits skin sensation and proprioception impulses to the central posterior gyrus of cerebral cortex.
(3) The posterior thalamus includes the medial geniculate body and the lateral geniculate body.The medial geniculate body has the medial geniculate body nucleus, which is the last relay station in the auditory conduction path. It receives the input of auditory fibers and sends them to the auditory center of the cerebral cortex.The lateral geniculate body has the lateral geniculate body nucleus, which is the last relay station in the visual conduction path. It receives the input of visual fibers, and sends fibers to the visual center of the cerebral cortex.
(4) The hypothalamus is the transitional area between the midbrain and diencephalon.
(5) The hypothalamus is the subcortical center of autonomic nerves, which is related to the secretion of certain hormones, emotional response, regulation of certain metabolism (such as water, salt, sugar, fat, etc.), regulation of body temperature, cardiovascular movement, respiratory movement, and regulation of appetite, sleep, awakening, biological clock (or circadian rhythm).Many physiological and psychological studies involve the diencephalon, especially the hypothalamus.
Both diencephalon and telencephalon are derived from the forebrain wing plate at the early embryonic stage. The diencephalon is located in the rear center of the forebrain, and the telencephalon develops into the left and right cerebral hemispheres.Due to the high expansion of the telencephalon, except for the ventral part of the diencephalon, which belongs to the hypothalamus, which is exposed on the surface of the brain, the rest of the diencephalon is surrounded by the left and right cerebral hemispheres.On the midsagittal section of the brain, the line from the posterior commissure to the posterior edge of the papillary body represents the junction between the diencephalon and the midbrain, and the line from the interventricular foramen to the chiasma represents the junction between the diencephalon and the telencephalon.The ventricles of the diencephalon are called the third ventricle.
The medial surface of the bilateral diencephalon forms the side wall of the third ventricle.At the junction of the medial surface and the dorsal surface, there is a prominent fiber bundle - thalamic stria medullaris, on which the choroid tissue of the third ventricle is attached.The medullary stria of the thalamus connects the habenular trigone backward. There is a habenular commissure between the left and right habenular trigones, and there is a pineal gland behind this commissure.At about the center of the third ventricular wall, there is an interthalamic adhesion (or central mass) connecting the left and right ventricular walls.It has a hypothalamic sulcus on its ventral side, which runs from the midbrain aqueduct to the interventricular foramen.The hypothalamic structure surrounds the bottom of the third ventricle, and there are optic chiasma, funnels, gray nodules and papillary bodies connecting the end plate from front to back.On the back of the diencephalon, both sides of the third ventricle are held by oval gray matter masses belonging to the dorsal thalamus, with protuberant anterior thalamic nodules in the front and enlarged occipital in the rear.On the lateral side of the back is the caudate nucleus belonging to the telencephalon, and between it and the diencephalon is the stria terminalis.There are medial geniculate body and lateral geniculate body at the lower outer side of the pillow.The outer side of diencephalon fused with the inner capsule of telencephalon.The ventral surface of the diencephalon is the part exposed on the brain surface. There are optic chiasma and optic tracts in front of it. The funnel, pituitary gland and gray nodule are in the middle. The papillary bodies are paired and located behind the gray nodule.
Diencephalon damage
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Each part of the diencephalon has its special function, but the main function is to accept and preliminarily integrate the somatic and visceral sensory (except smell) impulses, and relay them to specific sensory areas of the cerebral cortex;It is also the regulation center of autonomic nerve and endocrine under the cerebral cortex.Therefore, when the diencephalon is damaged, there will be sensory disturbance and spontaneous hypersensitivity, especially obvious pain allergy, as well as vegetative nerve and endocrine disorders, such as temperature, water metabolism, sleep, mood and other abnormal phenomena.
