The Common Vein Copyright 2010
Definition
Medial Geniculate Body Medial Geniculate Nucleus
The medial geniculate nucleus is associated with the thalamus. It functions in directing and maintaining attention. The medial geniculate nucleus is divided into three divisions; ventral, dorsal and medial. The ventral division detects frequency and intensity of auditory afferents. The medial and dorsal divisions have more difficult to discern function but are likely involved in processing auditory input as well.
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Whole Mount of the Midbrain in Axial Projection |
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The mounted and stained midbrain in transverse plane illustrates the component structures. The anterior border of the midbrain incorporates the cerebral peduncles (CP), and the substantia nigra (SN). Between the substantia nigra and the aqueduct (teal arrow) is an area of the midbrain called the tegmentum (floor of the midbrain) Within the tegmentum other structures include red nuclii (RNu), oculomotor nucleus (Nu3), periaquaductal gray (PAG), and the aqueduct of Sylvius which is border forming between the tegmentum anteriorly and the tectum (roof) posteriorly. The posterior end of the midbrain is bordered by the colliculi in the tectum. Note also the paired mamillary bodies anteriorly (MB) and the medial geniculate body (MG) posterolaterally Courtesy Department of Anatomy and Neurobiology at Boston University School of Medicine Dr. Jennifer Luebke , and Dr. Douglas Rosene 98483L.8 |
Lateral Geniculate Body Lateral Geniculate Nucleus
The lateral geniculate nucleus is located within the thalamus and is responsible for processing visual information. It receives information from the optic radiation and reticular activating substance (RAS) and sends effernts to the primary visual cortex in the calacarine fissure in the occipital lobe.
 Anatomic Coronal Section
Medial And Lateral Geniculate Bodies |
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The splenium of the corpus callosum places the cut relatively anterior through the frontal region. Parts of the midbrain that are visible include the red nucleus (RNu) substantia nigra (SN), and the erebral peduncle. Lateral to the midbrain are the medial geniculate nucleus (MG) and the lateral geniculate nucleus (LG). The pulvinar of the thalamaus lies superior to the LG and MG, and the distal part of the caudate (cau) lies in the floor of the lateral ventricle. Lastly on the inferior aspect and lateral to the midbrain the hippocampus (Hip) and optic radiation (OR) are noted. Courtesy Department of Anatomy and Neurobiology at Boston University School of Medicine Dr. Jennifer Luebke , and Dr. Douglas Rosene 97351.C12.9L01b |