Biomaterial Database

Morphology of basal optic tract terminals in the turtle, Pseudemys scripta elegans. 1998

J Martin, and N Kogo, and M Ariel

Department of Anatomy and Neurobiology, Saint Louis University, Missouri 63104, USA.

The morphologies of axon terminals of retinal ganglion cells projecting to the basal optic nucleus (BON) via the basal optic tract (BOT) were studied in the red-eared turtle. The BOT was visualized on the ventral surface of the brainstem in vitro, and either biotinylated dextran amine was injected extracellularly or neurobiotin was injected into physiologically identified axons during intracellular recordings. Up to 16 hours after tracer injection, the brains were fixed, sectioned parasagittally, and stained for biotin and Nissl substance. The diameters and depths of extracellularly filled axons were measured at three BON sites. Fourteen axons were reconstructed from serial sections with the aid of appropriate computer software. Analysis of extracellularly filled retinal axons revealed that about three times more axons were present just inside the rostral border of the BON compared with its caudal border. Thick (2-4 microm) axons were located within 100 microm from the ventral border, whereas thin (<2 microm) axons were found throughout the nucleus. Only the thinnest axons (<1 microm) extended caudally from the nucleus, indicating that some extracellularly labelled fibers passed through the BON. The intracellularly filled axons were more similar to the thick axons filled extracellularly and arborized entirely within the BON. All of the intracellularly filled axons had thick ventral trunks from which many thin branches extended dorsally and obliquely within the BON. The thin branches bifurcated repeatedly to form bead-like varicosities or boutons that often formed clusters within regions of 150 microm3 or less. These clusters may reflect areas of focused synaptic contact on BON cells with specific direction preferences.

UI	MeSH Term	Description	Entries
D007276	Injections, Intraventricular	Injections into the cerebral ventricles.	Intraventricular Injections,Injection, Intraventricular,Intraventricular Injection
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D009899	Optic Lobe, Nonmammalian	In invertebrate zoology, a lateral lobe of the FOREBRAIN in certain ARTHROPODS. In vertebrate zoology, either of the corpora bigemina of non-mammalian VERTEBRATES. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1329)	Corpora Bigemina,Optic Lobe, Non-Mammalian,Bigemina, Corpora,Non-Mammalian Optic Lobe,Non-Mammalian Optic Lobes,Nonmammalian Optic Lobe,Nonmammalian Optic Lobes,Optic Lobe, Non Mammalian,Optic Lobes, Non-Mammalian,Optic Lobes, Nonmammalian
D001931	Brain Mapping	Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.	Brain Electrical Activity Mapping,Functional Cerebral Localization,Topographic Brain Mapping,Brain Mapping, Topographic,Functional Cerebral Localizations,Mapping, Brain,Mapping, Topographic Brain
D001933	Brain Stem	The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.	Brainstem,Truncus Cerebri,Brain Stems,Brainstems,Cerebri, Truncus,Cerebrus, Truncus,Truncus Cerebrus
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
D001710	Biotin	A water-soluble, enzyme co-factor present in minute amounts in every living cell. It occurs mainly bound to proteins or polypeptides and is abundant in liver, kidney, pancreas, yeast, and milk.	Vitamin H,Biodermatin,Biokur,Biotin Gelfert,Biotin Hermes,Biotin-Ratiopharm,Biotine Roche,Deacura,Gabunat,Medebiotin,Medobiotin,Rombellin,Biotin Ratiopharm,Gelfert, Biotin,Hermes, Biotin,Roche, Biotine
D012165	Retinal Ganglion Cells	Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.	Cell, Retinal Ganglion,Cells, Retinal Ganglion,Ganglion Cell, Retinal,Ganglion Cells, Retinal,Retinal Ganglion Cell
D014426	Turtles	Any reptile including tortoises, fresh water, and marine species of the order Testudines with a body encased in a bony or cartilaginous shell consisting of a top (carapace) and a bottom (plastron) derived from the ribs.	Sea Turtles,Terrapins,Tortoises,Sea Turtle,Terrapin,Tortoise,Turtle,Turtle, Sea,Turtles, Sea
D014795	Visual Pathways	Set of cell bodies and nerve fibers conducting impulses from the eyes to the cerebral cortex. It includes the RETINA; OPTIC NERVE; optic tract; and geniculocalcarine tract.	Pathway, Visual,Pathways, Visual,Visual Pathway