What Is the Medial Geniculate Nucleus?

Medial geniculate body: medial geniculate body is the small mound behind the thalamic occipital, belongs to the posterior thalamus, is connected to the hypothalamus through the hypothalamus, and its deep cell group is the relay nucleus of the lateral thalamic auditory fibers . The fiber emitted by the nucleus constitutes the auditory radiation. The hind foot reaches the auditory region of the brain (temporal transverse gyrus) through the inner capsule, and the medial knee is the last change of the auditory conduction pathway.

Medial geniculate body: medial geniculate body is the small mound behind the thalamic occipital, belongs to the posterior thalamus, is connected to the hypothalamus through the hypothalamus, and its deep cell group is the relay nucleus of the lateral thalamic auditory fibers . The fiber emitted by the nucleus constitutes the auditory radiation. The hind foot reaches the auditory region of the brain (temporal transverse gyrus) through the inner capsule, and the medial knee is the last change of the auditory conduction pathway.

A component in the thalamus of the medial geniculate system. It is located in the posterior thalamus, under the thalamus occipital, and the hypocortical auditory center. The medial geniculate body is connected to the hypothalamus by the lower arm of the quadruplex.

Chinese name

Medial geniculate body

Foreign name

medial geniculate body, MGB

Nature

A medical term

Location

Under thalamus

Overview of the medial geniculate body :

1. Medial geniculate body:

The medial geniculate body is the humus behind the thalamus occipital, belonging to the posterior thalamus, connected to the hypothalamus through the hypothalamus, and its deep cell group is the relay nucleus of the lateral thalamus auditory fibers. The fiber emitted by the nucleus constitutes the auditory radiation. The hind foot reaches the auditory region of the brain (temporal transverse gyrus) through the inner capsule, and the medial knee is the last change of the auditory conduction pathway.

2. Lateral geniculate body:

The lateral geniculate body is located on the mesencephalon and is a component of the thalamus of the lateral geniculate system. The lateral geniculate body is located in the posterior thalamus, just below the thalamus pillow, and is the visual subcortical center. The lateral geniculate body is connected by the upper arms of the quadrilateral body and the superior colliculus. The outer side is connected to the optic tract, the inner side is connected to the superior thigh arm, and the deep cell cluster is the third-level neuron of the visual conduction pathway. Its somatic cells emit fibers to form visual radiation, and the foot stops in the visual area above and below the talus groove after passing through the inner capsule.

3. Lateral mound system:

The cuboid fiber runs to the anterior and lateral sides of the covered part and folds upwards on the outer side of the upper olive nucleus, which is called the lateral mound system. The lateral thalamus is part of the auditory pathway. Later it goes up the outer edge of the covered part, passes through the midbrain, and stops at the medial geniculate body of the thalamus.

The lateral mound system is a rising auditory fiber bundle. It emanates from the anterior and posterior nucleus of the cochlear nerve at the upper end of the medulla. It intersects between the base of the pontine and the covered part. After crossing the midline to form a cuboid, it folds upward and rises along the outer edge of the medial thalamus, ending in the hypothalamus Medial geniculate body. It is the second fiber in the auditory pathway.

4, thalamus:

The thalamus is the "dorsal thalamus". It is located at the bottom of the brain. It is an oval-shaped gray matter mass, which is adjacent to the third ventricle and outer to the inner capsule. In the human thalamus, it is an important relay station of sensory and motor impulses under the cerebral cortex, and it is also a subcortical high-level integration center for various nerve impulses.

Anatomy of the medial geniculate body :

1. Medial geniculate body:

The medial geniculate body is located below the thalamus occipital, one on each side, showing protrusions. The gray nucleus is called the medial geniculate nucleus, which is the auditory subcortical center. It is borrowed from the hypothalamus and the lower quadrant of the midbrain. The mounds are connected.

The medial geniculate body is the terminating nucleus of the lateral thalamus. The fibers emitted by the nucleus form the auditory radiation and reach the auditory center of the cerebral cortex. It is the last relay nucleus in the auditory conduction pathway.

2, thalamus:

The thalamus is an oval-shaped gray mass on the medial part of the dorsal mesencephalon, with a sagittal diameter of about 3 cm and a lateral and longitudinal diameter of 1.5 cm each. The outer side is the hind limb of the inner capsule; the inner side is the upper part of the lateral wall of the third ventricle; the back is the bottom wall of the lateral ventricle, and the outer end is separated from the caudal nucleus by the terminal striae; the ventral surface is the hypothalamus and the hypothalamus. The thalamus is a neuron-changing place for various sensations of the internal and external environment into the nervous system, including general sensation, proprioception, and special sensations (except smell). It forms the specific projection system of the thalamus, so it is called the highest sensory center under the cortex. The thalamus accounts for 4/5 of the mesencephalon. The inner pulp plate composed of afferent fibers and connecting fibers runs longitudinally back and forth in the "Y" shape in the thalamus, and divides the thalamus into anterior nucleus group, medial nucleus group, and lateral nucleus group. There are also a midline nucleus group located between the medial nucleus group and the third ventricle lateral wall, and a nucleus group located between the nerve fibers of the inner pulp plate. The cortical and thalamic fibers of the thalamus form a thin layer of white matter on the outside of the thalamus before they enter or leave the thalamus, that is, the outer pulp plate. There is a thin layer of nerve cells between the outer pulp plate and the inner capsule, the reticular nucleus of the thalamus. Patients with thalamic damage may experience various sensory symptoms, memory disorders, and language dysfunction.

Medial geniculate body and medial geniculate body:

The medial geniculate body and lateral geniculate body are relay stations of the auditory and visual pathways in the mesencephalon, respectively. The medial geniculate body receives fibers from the lateral thalamus, and the outgoing fibers form auditory radiation to the temporal lobe auditory cortex. The lateral geniculate body is below the pillow and includes 6 layers of cells. The cells on the ventral side are large and the cells on the back side are small. The fibers that cross in the optic bundle stop at layers 1, 4, and 6 of the lateral geniculate body, and those that do not cross stop at layers 2, 3, and 5. The fiber emitted from this point is emitted into the visual cortex of the occipital lobe.

Diseases related to the medial geniculate body:

Tumor of thalamus:

Overview:

Tumors of the thalamus are mainly gliomas, with astrocytomas the most, followed by polar glioblastomas and pleomorphic glioblastomas. Other such as sarcoma, tuberculoma occasionally. Younger and middle-aged people are more affected, and men are slightly more than women. The thalamus is deep and functional. The clinical manifestations of thalamic tumors vary. The main ones are the thalamic (Dejerine-Roussy) syndrome, including: sensory disorders on the contralateral side of the lesion, especially deep sensory disorders; paresis on the contralateral side of the lesion; spontaneous pain on the contralateral side of the lesion; Ataxia; Dance-like or finger movements on the limbs of the affected side. This syndrome is caused by thalamic occlusion of the thalamus and affecting the function of the posterior lower part of the lateral nucleus of the thalamus, the hind limb of the inner capsule, the medial side of the lateral geniculate body, and the lateral function of the medial geniculate body. It is rarely seen in patients with true thalamus tumors. Thalamic tumors usually develop insidious attacks, with an average duration of six months to one year. The first symptom is usually headache, and gradually increased intracranial pressure. Because the tumor only separates or compresses the surrounding tissues in the early stage, the focal signs can not appear for a considerable time. Later, as the tumor continues to grow, it invades the surrounding tissues, and it invades the brain stem along the ventricle wall, or passes through the middle. The mass spreads to the contralateral thalamus, which constitutes clinically different symptoms.

(1) Signs of increased intracranial pressure:

Occupation of the tumor in the skull or (and) compression of the interventricular foramen, third ventricle or aqueduct caused the cerebrospinal fluid pathway is blocked.

(2) The performance of limited damage is:

When the tumor develops into the anterior medial thalamus, mental disorders are more obvious, such as emotional changes, mental sluggishness, euphoria, drowsiness, incoherent speech, and even paranoia and depression. To the lower thalamus, there may be endocrine symptoms, such as obesity, drowsiness, diabetes insipidus and so on. Sensory disorders: The shallow sensation on the opposite limb of the lesion is only slightly diminished, and the distal parts of the upper and lower limbs have decreased tactile and pain sensations; deep sensory disorders are mostly manifested as ataxia and cortical sensory defects, namely: physical sensation, two points Decreased perception, unable to judge the location of the stimulus, etc. In some cases, limb apraxia can also be manifested, and the patient does not feel the affected limb at all, and he does not know that hemiplegia exists. When the development of thalamic tumors laterally affects the inner capsule, there may be "two deviations" (hemiplegic, hemiplegia). In addition to "triple deviation" (with isotropic blindness), sometimes the symptoms of extrapyramidal involvement are occasionally seen. In addition to the development of tumors to the thalamus pillow, in addition to the ipsilateral hemianopia of the lesions, the performance of the quadruplex can also affect the pupils of the pupils, visual disability in the eyes, tinnitus, and hearing impairment. Others: When the patient cries and laughs, the lower half of the opposite side of the lesion does not move, showing a mask-like shape, but when used as a free movement, the facial muscles can naturally contract "the disappearance of the psychomotor reflex"; affecting the cerebellum-red nucleus -Ataxia occurs in the thalamus pathway; seizures occur in some patients. Summarizing the above, for patients with increased intracranial pressure, if there is "two biases" or "triple biases", mental disorders, basal symptoms, etc., the possibility of thalamic tumors should be considered.