Biomaterial Database

The projection of the lateral geniculate nucleus to area 17 of the rat cerebral cortex. I. General description. 1976

A Peters, and M L Feldman

Lesions were made in the lateral geniculate nucleus of the rat and the consequent degeneration in area 17 of the cerebral cortex was studied by light and electron microscopy. These lesions produced prominent degeneration of axon terminals in layer IV extending into layer III and a much lesser amount in layers I and VI. The darkened degenerating axon terminals forming asymmetric synaptic junctions and were frequently surrounded by hypertrophied astrocytic processes. These terminals appeared to be disposed randomly, forming no discernible patterns. In layer IV 83% of the synapsing, degenerating terminals formed junctions with dendritic spines, 15% with dendritic shafts, and 2% with neuronal perikarya. The dendritic shafts and neuronal perikarya appeared to belong to spine-free stellate cells. The dendrites giving rise to the spines receiving degenerating axon terminals could not be identified, for most of the spines appeared as isolated profiles that could not be traced back to their dendritic shafts. One example of a degenerating axon terminal synapsing with an axon initial segment was encountered. Small, degenerating myelinated axons were prevalent in layers VI, V and IV, but were only infrequent in the supragranular layers. These results are compared with those obtained in other studies of thalamocortical projections.

UI	MeSH Term	Description	Entries
D008928	Mitochondria	Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Mitochondrial Contraction,Mitochondrion,Contraction, Mitochondrial,Contractions, Mitochondrial,Mitochondrial Contractions
D009410	Nerve Degeneration	Loss of functional activity and trophic degeneration of nerve axons and their terminal arborizations following the destruction of their cells of origin or interruption of their continuity with these cells. The pathology is characteristic of neurodegenerative diseases. Often the process of nerve degeneration is studied in research on neuroanatomical localization and correlation of the neurophysiology of neural pathways.	Neuron Degeneration,Degeneration, Nerve,Degeneration, Neuron,Degenerations, Nerve,Degenerations, Neuron,Nerve Degenerations,Neuron Degenerations
D009413	Nerve Fibers, Myelinated	A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. They are fibers of relatively large and varied diameters. Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers (NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves.	A Fibers,B Fibers,Fiber, Myelinated Nerve,Fibers, Myelinated Nerve,Myelinated Nerve Fiber,Myelinated Nerve Fibers,Nerve Fiber, Myelinated
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D002540	Cerebral Cortex	The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulci. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.	Allocortex,Archipallium,Cortex Cerebri,Cortical Plate,Paleocortex,Periallocortex,Allocortices,Archipalliums,Cerebral Cortices,Cortex Cerebrus,Cortex, Cerebral,Cortical Plates,Paleocortices,Periallocortices,Plate, Cortical
D005829	Geniculate Bodies	Part of the DIENCEPHALON inferior to the caudal end of the dorsal THALAMUS. Includes the lateral geniculate body which relays visual impulses from the OPTIC TRACT to the calcarine cortex, and the medial geniculate body which relays auditory impulses from the lateral lemniscus to the AUDITORY CORTEX.	Lateral Geniculate Body,Medial Geniculate Body,Metathalamus,Corpus Geniculatum Mediale,Geniculate Nucleus,Lateral Geniculate Nucleus,Medial Geniculate Complex,Medial Geniculate Nucleus,Nucleus Geniculatus Lateralis Dorsalis,Nucleus Geniculatus Lateralis Pars Dorsalis,Bodies, Geniculate,Complex, Medial Geniculate,Complices, Medial Geniculate,Corpus Geniculatum Mediales,Geniculate Bodies, Lateral,Geniculate Bodies, Medial,Geniculate Body,Geniculate Body, Lateral,Geniculate Body, Medial,Geniculate Complex, Medial,Geniculate Complices, Medial,Geniculate Nucleus, Lateral,Geniculate Nucleus, Medial,Geniculatum Mediale, Corpus,Geniculatum Mediales, Corpus,Lateral Geniculate Bodies,Medial Geniculate Bodies,Medial Geniculate Complices,Mediale, Corpus Geniculatum,Mediales, Corpus Geniculatum,Nucleus, Geniculate,Nucleus, Lateral Geniculate,Nucleus, Medial Geniculate
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001253	Astrocytes	A class of large neuroglial (macroglial) cells in the central nervous system - the largest and most numerous neuroglial cells in the brain and spinal cord. Astrocytes (from "star" cells) are irregularly shaped with many long processes, including those with "end feet" which form the glial (limiting) membrane and directly and indirectly contribute to the BLOOD-BRAIN BARRIER. They regulate the extracellular ionic and chemical environment, and "reactive astrocytes" (along with MICROGLIA) respond to injury.	Astroglia,Astroglia Cells,Astroglial Cells,Astrocyte,Astroglia Cell,Astroglial Cell,Astroglias,Cell, Astroglia,Cell, Astroglial
D001369	Axons	Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.	Axon
D013569	Synapses	Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.	Synapse